1．Purpose and Outline of the Study

１．Purpose and Outline of the Study １．Purpose and Outline of the Study

This study has been achieved for 39 months from October, 1999 to December, 2002 by Dowa Engineering Co. Ltd. and Mitsui Mineral Development Engineering Co. Ltd. based on the "Scope of work (S/w)" signed on June 4th, 1999, between Japan International Cooperation Agency (JICA) and Empresa Nacional de Minería (ENAMI) for the study on "Environmentally-Friendly Operation of Mineral Processing Plant Using Biotechnology in the Republic of Chile" (hereinafter referred to as the Study). The Republic of Chile (hereinafter referred to as Chile) is the world’s largest producer of copper producing 4.6 million tons of the metal per year, but the other hand, there is increasing nationwide concern on environmental pollution in these days through rising consciousness and severer regulations than ever before. The main object of the Study is to introduce environmentally friendly operation using iron-oxidizing bacteria for waste water (solution) treatment, which has already been applied successfully in Japan, into mineral industry in Chile. For this purpose a model plant, with about 100m3 per day of capacity to purify the waste solution, was installed at the site of the existing Ovalle leaching plant for demonstration test run as well as for technology transfer on this subject. A series of test results, are summarized in the Chapter 4 of this report. For a large amount of investment to protect surrounding environment, it is inevitable to stabilize existing process and to improve operation results. In the present situation of Ovalle, ENAMI, some technical and environmental problems are found out to be solved, and also some unavoidable factors resulted from ENAMI’s standpoint. To clarify these matters first, outline of ENAMI’s position and its roles in the Chilean copper industry are generally described in the Chap. 2. Then, the results of Ovalle plant examination in the viewpoints of technical and environmental aspects are summarized in the Chap. 3 including economical consideration. This Report itself should be a warning and an important recommendation to be positioned in the environmental aspect. The above-mentioned model plant was installed for test operation only and incapable of industrial scale operation. Thus, so-called “Full scale treatment plant”, of which capacity meets the total volume of waste solution from the preceding leaching section, was designed for a future program. The total volume of the solution corresponds to the maximum capacity of the leaching section, 14,000 tons per month. Specifications and constructing costs of this full scale treatment plant are described in the Chap. 5. In the Chap. 6, economical and financial analyses are broadly made to discuss the feasibility on the overall Ovalle plant including the waste solution treatment. As the main target of this Study was aimed at countermeasures against pollution, improvement of monthly profit is hardly expected directly from this investment. Accordingly in this Report, effects of environmental impact on outside community, meadow and farmland, were analyzed quantitatively for justification of the waste solution treatment plant. Construction of the full scale plant is inevitably accompanied a large amount of investment.

1-1 Judging from the current situation of copper industry as well as ENAMI’s itself, it would be unlikely to realize the investment at once. In this Report, the full scale plant is strongly proposed for future program, when copper industry returned to another prosperity, on the other hand, more practicable countermeasure without causing pollution problems is studied as long as the current low level of operation is continued. This is described concretely in the Chap. 7. Treatment of the waste solution with use of bacteria was technically proved through the Model plant operation. One purpose of this Study was application of this technology to other industrial sites in Chile. This is discussed in the Chap. 8, however, any mines or plants, which can introduce this technology as easily as Ovalle plant, are not found out inside Chile because copper precipitation process after leaching has been declining in recent years and even among the ENAMI plants, no promising future can not be seen to develop this operation. Thus, in the Chap. 8, general technical discussion is made on some industrial sites for any possibility of the application of this bio-technology. Now that this technology was satisfactorily transferred, it is expected to be developed by the hand of Chilean counterparts. In the Chap. 9, discussions are summarized for conclusion of the Study. Through the realization of these proposals, Ovalle plant is expected to be a model plant inside Chile both in the technically and environmental standpoints.

1-2

２．Mining Situation in Chile ２．Mining Situation in Chile

2.1 Outline of Mining Industry Chile has a leading role in the mining industry in the world, operating many metal mines especially in theⅡ andⅢ region, the northern part of the country as shown in Figure 2-1. Export of mining products (US$ 8.34billion in 2000), mainly represented by copper(Cu), gold(Au), silver(Ag), molybdenum(Mo) etc., records as many as 47% of the total amount. Especially export of Cu reached US$ 7.34billion in 2000 accounting for 41.5% of the total. Production of Cu has been increased year by year recording 4.6 million tons in 2000, 35% of the world production, which now reaches 13.2 million tons a year. Chile has been the leading producer since 1982, when exceeded U.S. in Cu production (Refer to Figure 2-2.).

NOTE ○ Copper Mine (Porphyry copper deposit) □ Copper Mine (Mantle type deposit) ◇ Gold mine △ Other Mine (・Mine under production) Main copper smelting and refinery ■ State capital

Figure 2-1 Major Mine Location in Chile

2-1 Copper production of Chile World share (%) 5,000,000 50

4,500,000 45

4,000,000 40

3,500,000 35 ）

t/y 3,000,000 30 （ 2,500,000 25

2,000,000 20

1,500,000 15 World share (%) Production Production

1,000,000 10

500,000 5

0 0 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 Period (year)

Figure 2-2 Recent Copper Production

Forms of Cu products are illustrated in Figure 2-3. Around 1990, 60% of Cu was produced as electrolytic Cu, while in these days nearly 40% are shipped as Cu concentrate for further smelting abroad, followed by SX-EW cathode and electrolytic Cu by about 30% for each.

1990 2000

Amount of production：1,588,400t Amount of production：4,603,300t

SX-EW cathode copper Blister copper SX-EW cathode Others 8% Blister copper 4% copper

9% 30% Copper Cathode copper concentrate 28% 16%

Copper Cathode copper concentrate 60% 38% Figure 2-3 Forms of Cu Products

As illustrated in Figure 2-4, Japan is the largest destination from Chile, accounting for 17.4% of the total export, followed by the People’s Republic of China and the Republic of Korea. Cu export for the Southeast Asia from Chile accounts for 42.5% if Taiwan is included.

2-2

Argentine 1% Others Japan Sp ain 20% 17% 2% U.K. China 3% 12%

Taiwan 5% Kerea France 8% Brasil U.S.A Italy 5% 6% 8% 8% Germany 5%

FigureFig. 2-4 2-5 Destination Destination of Copperof copper Export export (2000) (2000)

2-3 2.2 Environmental Related Organization and Regulations in Chile Environmental regulations date back to 1916 with “Regulations on neutralization and purification of industrial wastes”. Since then, others have been arranged under international movement, that is, “Sulfur dioxide from smelters”, “Standards of floating dust” and “Regulations on water pollution” in 1991 as well as “ Environmental basic regulations” established in 1994.

1916 ・Regulations on neutralization and purification of industrial wastes 1970 ・Regulations on construction and control of waste tailing dams 1991 ・Regulation on plant operation discharging sulfur dioxide, dust and arsenic 1992 ・Regulations on neutralization and purification of industrial wastes (enforcement) 1994 ・Fundamental law on the natural environment ・Regulations on national and regional environmental advisory committee 1995 ・Regulations on promulgation of environmental and discharge standards ・Regulations for procedure of pollution control program 1997 ・Regulations for environmental assessment ・Discharge standards of pollutants accompanied with industrial waste water 1998 ・Standards of arsenic discharged into atmosphere ・Standards of polluting elements contained in liquid wastes discharged into the sea or 2000 surface water

Other regulations than listed above, “Discharge standards into underground water”, “Discharge standards into the sea”, “Environmental standards for protection of surface water” and “Law on mine closing measures” are now being prepared for establishment. Among the environment related regulations, “Fundamental law on the natural environment” is the core, in which the followings are provided. Environmental education and research Environmental assessment Participation of local society in environmental assessment process Environmental standards Discharge standards Environmental and pollution control program Liability for environmental damages CONAMA

The above listed CONAMA plays the important part in the environmental control of Chile. Its major duties are described below. Environmental policy of the Government to be submitted to the President Recognition of practical situation of the environmental regulations currently in force

2-4 Consultation, analysis, transmission and adjustment of environmental affairs Control on environmental assessment system (SEIA) and adjustment for making up environmental standards Environmental education and promotion programs

When any environmental project is started, it is inevitable through SEIA, above-mentioned, to submit a study report or declaration on its impact to COREMAS (local environmental committee, subordinate to CONAMA) for final approval. As for this Ovalle project, the declaration was already submitted to COREMAS and approved. The organization of CONAMA and related institutions is illustrated in the following diagram.

President of the republic Secretary-general of the presidency

Directive Council (Chairman) Secretary-general of the presidency Executive address Committee of CONAMA’s counselors （Committee） CONAMA Head secretary of the presidency Executive director Ministry of 2 Scientist Foreign Affairs, Defense 2 Rep. of NGO Economic, Development plan 2 Rep. of Academic Education, Public works 2 Rep. of Enterprise Healthy, House 2 Rep. of workers Agricultural, Mining 2 Rep. of the presidency Transport, Financial

CONAMA

Service Publishes Commission regional Committee of local counselors of the environment (COREMAS) （Committee） Regional address (Chairman) 2 Scientist CONAMA Head of local government 2 Rep. of NGO Regional director （Committee） 2 Rep. of Enterprise State governors 2 Rep. of workers SEREMI's of integral ministries 2 Rep. of Local public office of the adviser

4 Local counselors

Technological committee Relate： of COREMAS (Chairman) Hierarchical Local director of CONAMA （Committee） Functional Local director of public organization Consultation which relates to environment

Figure 2-5 Organization Chart of CONAMA and Related Institutions

2-5 2.3 Outline of ENAMI The National Mining Company, ENAMI (Empresa Nacional de Mineria), was created in 1960 from the merger of the Fund for the Promotion and Funding of Mining (Caja de Credito y Fomento Minero) and its subsidiary, the National Smelting Company (Empresa Nacional de Fundiciones). Compared with another national mining company, CODELCO (Corporacion Nacional de Cobre de Chile), which is a giant profit-making enterprise operating world famous copper mines like Chuquicamata, El Teniente and others, ENAMI devotes itself to promote the development of small and medium-scale mining. Thus, without operating its own mines, ENAMI provides small or medium scale miners with partially subsidized services at purchase of ores to boost productivity, especially when copper price is unfavorable to the industry. Finally, ENAMI achieves its roll by processing these crude or intermediate materials through its plants and smelters to widely marketable products, like electric copper, gold, silver and the like. In other words, ENAMI acts processing as well as marketing service on behalf of small or medium miners to promote this important sector of the nation. Its concrete measures are summarized as follows. ① Support mine development by financing Development of mines is usually accompanied with financial risks because market price of copper often fluctuates. ENAMI provides the miners with long or short term loans, guarantee against risks and other benefits to promote the development. ② Ore processing ENAMI processes crude ores from small or medium scale miners at the following plants through flotation or leaching process up to copper concentrate or precipitate respectively. Treatment capacity of each plant is listed below. At purchasing crude ores, ENAMI provides these miners with incentive payment to encourage them. Concretely when copper price goes down below 75¢ /lb, ENAMI pays them the difference, which shall be paid back when the price rebounds.

Table 2-1 ENAMI’s Processing Plants Capacity（t-crude ore / month） Name State Product Oxide ore Sulphide ore Total Copper precipitate / Copper Taltal Ⅱ 12,000 15,000 27,000 concentrate Matta Ⅲ － 110,000 110,000 Copper concentrate Copper precipitate / Copper Vallenar Ⅲ 12,000 20,000 32,000 concentrate El Salado Ⅲ 18,000 － 18,000 Copper precipitate Copper precipitate / Copper Ovalle Ⅳ 14,000 11,000 25,000 concentrate Total 56,000 156,000 212,000

Thus, copper precipitate is recovered from oxide copper ores through leaching and

2-6 precipitation method, while copper concentrate is recovered from sulfide ores through flotation process. Both are delivered to ENAMI’s smelters for final treatment. Besides, some gold bearing crude ores are treated separately at the plants to concentrate this metal by flotation. As a new processing for oxide copper ores, modern solvent extraction called SX-EW process has been adopted widely replacing traditional leaching- precipitation. Currently, this is a leading process for oxide copper treatment especially for large scale mining operation. ENAMI is also studying this technology and has started plant installation at El Salado. As stated above, all of ENAMI plants depend upon outside suppliers for crude materials. Thus, it is difficult to keep feed amount constant due to fluctuation of ore material. At almost all plants, monthly throughput of ores is far below the installed capacity due to shortage of raw materials. Storage and blending of crude ores are also unpractical because they have to be evaluated quickly and separately to report the suppliers. Actual results of Ovalle plant are described in the Chap. 3. ③ Custom smelting At Ventanas and Paipote smelter, ENAMI treats copper concentrates and precipitates delivered from the above processing plants and also from the third parties. Ventanas smelter has an assembly line from smelting to electrolytic refining and produces electrolytic copper, gold, silver and selenium as well as sulfuric acid. On the other hand, Paipote produces anode copper through smelting, which is refined at Ventanas. As ENAMI gives the third party incentive payment, difficulty often remains to make sufficient profit under current situation of copper price. Decrease in operation costs is urgent but now total costs have been higher due to additional payment for protection of environment.

Table 2-2 Actual Results of ENAMI Smelting and Refining Operation (2000) Ventanas Paipote Electrolytic copper 319,105 t － Blister copper － 77,639 t Electrolytic gold 5,937 kg － Electrolytic silver 105,401 kg － Sulphuric acid 328,542 t 245,707 t

④ Engineering and others ENAMI develops research programs like operation improvement, unique technology, environmental countermeasures etc., by itself or jointly with other party. As recent

achievements, introduction of Teniente Converter, increase in SO2 recovery from discharged gas and study on SX-EW process replacing traditional copper precipitation

2-7 method are mentioned. ENAMI’s business and services in the mining industry are reviewed above. Compared to CODELCO again, CODELCO produces 1.5 million tons of copper annually, ENAMI’s output production from its smelters is only about 320 thousand tons, one fifth of the former. But ENAMI’s role inside Chilean copper industry is so great for small and medium scale miners that they can compete with larger mines technically and commercially assuring employment by themselves. Figure 2-6 shows the organization chart of the Ministry of Mines, which controls mining related institutions in Chile. Further, Figure 2-7 is the organization inside ENAMI.

Legislative power Administrative power Jurisdiction

President of the republic

Regional Office of Ministries Mining ministry Ministry

Mining public Mining geological Nuclear energy corporation features bureau committee (ENAMI) (SERNAGEOMIN)

Copper public Chile copper Oil public corporation corporation committee (ENAP) (CODELCO) (COCHILCO)

Figure 2-6 Organization Chart of the Ministry of Mines

2-8

Mining public corporation (ENAMI) The president law adviser Public relations department Board of directors

Executive Office

Vice president Management strategy department

Quality control department

Development Commercial Administration and Human affairs Mining part department department financial department department

Plant administrate Hernán Videla Lira Las Ventanas Matta plant department Refinery Refinery

Taltal plant Salado plant Vallenar plant Ovalle plant

Figure 2-7 Organization Chart of ENAMI

Source：Annual report ENAMI, 2000 Compendio de la Minera Chilena, 2000

2-9

３．Examination of Ovalle Production Plants ３. Examination of Ovalle Production Plants

3.1 Outline of Ovalle Plants

3.1.1 Location (1) Location and transport This plant is situated at latitude 30.30’ south and 71.06’ west, 8km north from Ovalle city in Limari area, which is located at about 70km south from La Serena city (*1), capital of the Ⅳ region of the Republic of Chile. The plant is 444m above the sea level and faces Route No. 43, which connects La Serena and Ovalle. From La Serena it takes about one and half hours by car. *1 : 475km north from Santiago and 50 minutes by plane (2) Landform This area is called Cerro negro mountain area forming a coast mountain range. The plant is situated on a open slope of plateau facing a river, constructed after leveling the ground. (3) Water basin Underneath the plant flows the river Ingenio, a branch stream of the Limari, from NE to SW with about 1～8m3/min. of water volume. The water springs at a riverbed about 6km upper stream from the plant, forming the Ingenio wet marsh zone and joins the river Limari at about 12km downstream from the plant. Another water stream taken from Recoleta irrigation reservoir, called Talhuen, runs through the plant and further drinkable water is springing at eastern bank of the Ingenio, a little above the plant. (4) Climate During the dry season (Oct. through March), rainfall is scarce in this mountain zone. It is clear all day though foggy in the morning at the sea side. During the rainy season, on the contrary, it is cloudy and sometimes heavily rains. The maximum rainfall recorded 110mm/day in May, 1957 and in 1997 a flood was caused by heavy rain. Annual rainfall varies between 1～340mm/year but after 1993 it is less than 10mm/year except 1997. 3.1.2 History ・1959 Compañia Minera de Panulcillo S.A. was founded. Started production of copper (Cu) precipitate through percolation leaching and Cu precipitation. ・1967 Ore purchase and mine renting system were introduced because ore was exhausted. ・1971 Operation was taken over by ENAMI and COMINA (Compañia Minera Nacional). Flotation plant with capacity of 150ton/day was installed. Four years later increased up to 300ton/day. ・1979 Operation was taken over by the mining association and mining co-op of Ovalle city. ・1981 Operation stopped due to economic difficulty ・1982 Operation was taken over by ENAMI and COMINA. Maquila contract was signed with ENAMI.

3-1

・1987 Heap leaching (13,000ton/month) was introduced. Production of Cu precipitate was started. ・1995 Infrastructure renewed. Process optimized. Management considering environmental situation. Automatic agglomeration installed. Cu precipitation process exchanging for iron scrap was started. Waste disposal dam constructed. Dynamic heap leaching was introduced replacing agitation and percolation leaching. Capacity of agglomeration and Cu precipitation was increased up to 100ton/h and 240ton/month respectively. ・1999 Started as present Ovalle plant under direct control of ENAMI.

3.1.3 Production (1) Situation of plant operation Oxide and sulfide Cu ores are being processed. After 1998, when Cu price fell below 80¢ /lb, operation has been inactive due to decrease in ore supply and consequently lower utilization of installed plant capacity. Table 3-1 shows the outline of plant operation. Table 3-1 Production Situation of Ovalle Plant, ENAMI Oxide copper ore Sulfide copper ore

Chalcopyrite: CuFeS2,

1.Processing Chrysocolla: CuSiO3･nH2O, Bornite: Cu5FeS4,

minerals Malachite: CuCO3･Cu(OH)2, etc. Covelline/Covellite: CuS,

Chalcocite: Cu2S, etc. Precipitation process (Cementation process):Crushing + Agglomeration Flotation process: Crushing+ 2.Treatment + Leaching + Precipitation ⇒ Grinding + Flotation ⇒ Product: process Product: Copper precipitate Copper concentrate with recovery (Cement copper) with recovery of of Cu, Au, Ag, etc. only Cu. 84,000t/year[until summer, 2002]- 3.Capacity 168,000t/year 132,000t/year[after summer, 2002] Purchase from neighboring many middle, small and micro scale mines 4.Purchase of with incentives, because ENAMI has not any own mines according to the crude ore law of establishment of ENAMI to subsidize the mines. : Ore transportation distances are 3 to 120km. (bulk: 20～50km) 5.Quantity of Crude ore: 42,365t/year [Grade Cu Crude ore: 47,418t/year [Grade Cu treatment 2.3%] : RCU (Rate of capacity 1.7%, Au 0.3g/t and Ag 3.5g/t] in 2000 utilization) 25.2% : RCU (same as in the left) 56.4%

3-2

Oxide copper ore Sulfide copper ore Copper concentrate 3,068t/year Copper precipitate (Cement copper) [Grade Cu 22.3%, Au 2.0g/t, Ag 6.Quantity of 894t/year [Grade Cu 82.9%], 88.3g/t], [Recovery Cu 84.3%, Au production [Recovery Cu 77.3%], [Quantity of 42.1%, Ag ---%], [Quantity of in 2000 metal Cu 741t/year] metal Cu 684t/year, Au 6.3kg/year, Ag 270.9kg/year] 7.Disposal of To Ventanas copper smelter of ENAMI products Note: Ovalle plant treats a very slight quantity of gold ore too in addition to copper ore.

(2) Position of output production Table 3-2 shows how Ovalle plant is ranked in Chilean Cu producing industry. In 2000, the plant produced 1,425 tons of Cu, which accounts for only 0.03% of total domestic production, that is, 4,614.1×103 ton/year. But it should be noticed that ENAMI does not always stick production rank but aims at the promotion of the small and medium size miners.

Table 3-2 Position of Ovalle Plant in Chilean Cu Production(*2) (in 2000) Quantity of copper production(*2) Number of Cu Share mines (and ×103t/year % concentrators) 1. (Ovalle plant, ENAMI) (1.4)(*6) (0.03) (0.01) (1) 2. Governmental: ENAMI 11.4 0.3 0.1 4(*7) 3. Governmental: CODELCO(*3, 4) 1,612.4 34.9 12.2 6(*8) 4. Private(*5) 2,990.3 64.8 22.6 27(*8) Total of Chile: 2.+3.+4. 4,614.1 100.0 34.9 36(*9) Total of the world 13,230.0 100.0 *2 : Production based on processing plants not on smelters. In Chile, only 7.4×103 ton/year of Cu out of ENAMI’s production and other minor portion are derived from Cu precipitate. Others are from sulfide Cu concentrate or cathode Cu through oxide Cu processing. *3 : Corporacion Nacional del Cobre de Chile *4 : Including CODELCO’s quota (49%) in El Abra operation

3-3

*5 : Excluding CODELCO’s quota (49%) in El Abra operation In Cu production, Escondida mine holds the first place treating 175×103 ton/day of sulfide crude ores (Cu 2.1%) and 70×103 ton/day of oxide (Cu 0.68%) and produces 916.6 ×103 ton/year of Cu metal (Cu concentrate : 2,021.5×103 ton/year, Cu grade 38.4%, from sulfide ores as well as cathode Cu : 140.2×103 ton/year, Cu grade 99.99% from oxide ores). This production accounts for 19.9% of total Chile and as many as 6.9% of world production. *6 : Production of individual ENAMI plant is listed in Table 3-3. *7 : Out of five plants one has suspended operation in 2000. *8 : Including El Abra mine *9 : El Abra is not counted more than once. 3.1.4 Environment Along the upper stream of the river Ingenio from Ovalle plant, no natural contamination is observed. On the contrary, the downstream from the plant is extensively contaminated by

yellow green color of ferrous sulfate, FeSO4, and red brown sediment of ferric hydro-oxide, Fe

(OH)3. Supposedly, these are caused by ferrous ions penetrated into the soil from the evaporation ponds(*10), which accumulate untreated waste solution from the leaching process. *10: Formerly, the bank of the pond once collapsed when hit by earthquake. This river water is partly used for irrigation but its iron content is above the standards for the use. Accordingly, Ovalle plant paid the agricultural bureau US$ 4,500 of fine in the past. The new effluent standards applied to Ovalle plant were notified in the official gazette of March, 2001 with five year’s grace period. Thus, the plant is strongly requested by CONAMA (National environmental committee) to take necessary measures by then. On the other hand, flotation tailings from sulfide ore processing are piled up into the stock dam, of which overflow water is all circulated for reuse. No pollution is seen from this section.

3.1.5 Location of Ovalle plant and related facilities Figure 3-1 illustrates correlated location of the plant and related facilities as well as surrounding water streams.

3-4

Table 3-3 Result of Operation of ENAMI Mineral Processing Plants in 2000 Source: MEMORIA ANUAL 2000, ENAMI Item Taltal El Salado Vallenar Ovalle *9 Subtotal M. A. Matta 1. Installed Capacity: by calculation 1) Oxide copper ore (crude ore) dry t/year 144,000 148,000 144,000 168,000 604,000 2) Sulfide copper ore (crude ore) dry t/year 180,000 240,000 84,000 504,000 1,320,000 1)＋2) amount of Installed Capacity dry t/year 324,000 148,000 384,000 252,000 1,108,000 1,320,000 2. Reception: supply from mines 1) Oxide copper ore (crude ore) dry t/year 55,754 116,710 32,424 61,530 266,418 Closed by ore 2) Sulfide copper ore (crude ore) dry t/year 121,009 11,721 47,570 180,300 shortage 3. Mineral Processing 1) Oxide copper ore (crude ore) *1, *2 dry t/year 71,155 116,710 35,397 53,173 276,435 : Rate of capacity utilization %4979253261 *8 2) Sulfide copper ore (crude ore) *1, *3 dry t/year 114,709 9,895 47,418 172,022 : Rate of capacity utilization % 64 4 56 35 1) + 2) mineral processing ore tonnage dry t/year 185,864 116,710 45,292 100,591 448,457 3) Gravel (waste ore at primary leaching) *4 dry t/year 24,000 71,383 0 62,504 157,887 4. Product 1) Copper precipitate *5〈from oxide Cu ore〉 tonnage dry t/year 3,082 3,452 1,067 1,390 8,991 Copper grade % 79.66 84.03 81.51 81.95 81.91 3-5 Copper tonnage dry t/year 2,455 2,901 870 1,139 7,365 Copper recovery % 77.80 77.66 80.97 75.87 77.81 2) Copper concentrate 〈from sulfide Cu ore〉 tonnage dry t/year 10,168 1,054 3,072 14,294 Copper grade % 30.76 23.87 22.52 28.43 Copper tonnage dry t/year 3,128 252 684 4,064 Copper recovery % 93.20 100.37 84.40 91.96 5. Cost: operation 1) Purchase of oxide/sulfide copper ore (crude ore) US$/t 2.42 5.33 7.07 4.10 4.00 2) Crushing US$/t 1.62 1.91 9.30 1.94 2.54 3) Flotation *6 US$/t 8.92 6.16 10.73 9.38 4) Leaching *7 US$/t 21.9 22.30 11.36 17.27 19.81 5) Processing of oxide ore : 1) +2) +4) US$/t 25.94 29.54 27.73 23.31 26.35 ¢ /Cu-lb 34.1 53.9 51.2 49.4 44.9 6) Processing of sulfide ore : 1) +2) +3) US$/t 12.96 22.53 16.77 15.92 ¢ /Cu-lb 21.6 40.1 52.7 30.6 Note *1: Different from reception ore tonnage because of stock pile between reception and processing, *2: Crushing →Agglomeration→Leaching→Precipitation→Filtering, *3: Crushing→Grinding→Flotation→Filtering, *4: It is assumed that the waste ore at primary leaching should be releached, but relation to other columns is not clear., *5: cement copper, *6: [Assumption] Grinding+Flotation+Filtering, *7: [Assumption] Agglomeration+Leaching+Precipitation+Filtering, *8: 46% in case of by calculation. *9: Values of Ovalle plant calculated by ENAMI headquarter are different from them by Ovalle site. Q-2

H-1

Q-1

H-2

A~L, R, S ：Treatment plants and facilities related N ：Waste rock piling site, tailing ponds and waste water evaporation ponds P ：Canal for drainage of waste water infiltrated from evaporation ponds. Q-1 ：River Q-2 ：Irrigation canal Note) Refer to the next page for details.

Figure 3-1 Location of Facilities of Ovalle Plant

3-6 Details of legend for Figure 3-1 Ａ：Main front gate of Ovalle plant Ｂ：Materials warehouse Ｃ：Main office Ｄ：Plant cultivation house for mine pollution prevention vegetation Ｅ：Acceptance ore stock yard: for oxide ores and sulfide ores Ｆ：Crushing section for oxide ores and sulfide ores Ｇ：Agglomeration section for oxide ores Ｈ：Leaching section for oxide ores Ｈ-1 Primary leaching section (heap leaching) with leaching solution ponds Ｈ-2 Secondary leaching section (dump leaching) with leaching solution ponds Ｉ：Precipitation (iron substitution and copper precipitation) section for oxide ores Ｊ：Copper precipitation sun dryness section for oxide ores Ｋ：Grinding and flotation section for sulfide ores Ｌ：Copper concentrate sunlight drying section for sulfide ores Ｎ：Waste ore stock pile and evaporation ponds for oxide ores, and tailing ponds for sulfide ores Ｎ-1 Sulfide copper ores: tailing pond 1 for old operation Ｎ-2 Sulfide gold ores: tailing pond 1 for old operation Ｎ-3 Sulfide copper ores: tailing pond 2 for present operation Ｎ-4 Sulfide gold ores: tailing pond 2 for old operation Ｎ-5 Oxide copper ores: percolation leaching waste ore for old operation Ｎ-6 Oxide copper ores: agitation leaching waste solution evaporation pond for old operation Ｎ-7 Oxide copper ores: leaching waste ore 1 for old operation Ｎ-8 Oxide copper ores: leaching waste ore 2 for old operation Ｎ-9 Oxide copper ores: leaching waste ore 3 for present operation Ｎ-10 Oxide copper ores: leaching waste ore 4 for present operation Ｎ-11 Oxide copper ores: leaching waste solution evaporation pond 1 Not operation after the model plant was Ｎ-12 Oxide copper ores: leaching waste solution evaporation pond 2 started to operate in Sep., 2001. Ｎ-13 Oxide copper ores: leaching waste solution evaporation pond 3 with HDPE seat lining (plan) Ｎ-14 Oxide copper ores: leaching waste solution evaporation pond 4 with HDPE seat lining (plan) Ｎ-15 Oxide copper ores: leaching waste solution evaporation pond 5 for outflow waste solution for old operation : There has been a collapse of the river side bank because of earthquake. Ｎ-16 〃 6 for outflow waste solution for old operation Ｎ-17 〃 7 for outflow waste solution for old operation Ｎ-18 〃 8 for outflow waste solution for old operation Ｎ-19 〃 9 for outflow waste solution for old operation Ｎ-20 〃 10 for outflow waste solution for old operation Ｎ-21 〃 11 for outflow waste solution for old operation Ｎ-22 Sulfide gold ores: tailing pond 3 for old operation Ｎ-23 Sulfide gold ores: tailing pond 4 for old operation Ｎ-24 Sulfide gold ores: tailing pond 5 for old operation Ｎ-25 Oxide copper ores: leaching waste solution evaporation pond 12 for outflow waste solution for old operation Ｐ：Discharge canals for waste solution outflowed from evaporation ponds Ｐ-1 Discharge canal 1 for waste solution outflowed from evaporation pond Ｐ-2 Discharge canal 2 for waste solution outflowed from evaporation pond Ｐ-3 Discharge canal 3 for waste solution outflowed from evaporation pond Ｑ：River and irrigation canal Ｑ-1 Ingenio river Ｑ-2 Talhuen irrigation canal for water supply Ｒ：Model plant to treat waste solution from the leaching section Ｓ：Test pilot plant to produce copper sulfate from pregnant leaching solution

3-7 3.2 Examination of Plant Operation For stabilization of management performance and also for new investment of environmental countermeasures and others, it is inevitable to improve productivity and profits. In this section, profit increase and cost reduction at Ovalle production plants are generally discussed.

3.2.1 Comparison of various processing methods for Cu ores. At Ovalle, oxide copper ores are processed through leaching-precipitation method to produce Cu precipitate, while sulfide ores are by flotation to produce Cu concentrate. For general information, usual processing methods for two types(*1) of Cu ores are summarized in Table 3-4, considering the key factors like component minerals, production flow, possibility of by-product recovery, operating costs, operation scale and others. *1 : Oxide copper ores (leaching-precipitation or solvent extraction/electro-winning method) Sulfide ores (flotation-smelting-electrolytic refining) 3.2.2 Oxide ores (1) Process at Ovalle Oxide ores are processed by usual precipitation method, that is, crushing → agglomeration → leaching → precipitation (exchanging for iron scrap), to produce Cu precipitate. Outline of flow diagram and material balance are shown in Figure 3-2 and the flow diagram with related facilities are in Figure 3-3 respectively. (2) Operation results After 1998, when market price of copper fell below 80¢ /lb, production has been inactive due to lower level of ore supply from outside. The actual operation results since 1994 are shown in Table 3-5～3-11, unit cost of treatment (2000) is shown at the bottom line of Table 3-3 (section 3.1), and unit consumption of major materials are in Table 3-12 respectively.

Table 3-12 Unit Consumption of Major Materials (Oxide Cu ores) Electricity Sulfuric acid Scrap iron Unit consumption 5.57kwh/crude ore t 7.11kg/productive Cu-kg 1.22kg/productive Cu-kg Unit price 0.052US$/kwh 38.00US$/t 65.00US$/t Unit processing 0.29US$/crude ore t 4.73US$/crude ore t 1.39US$/crude ore t Cost 0.8¢ /productive Cu-lb 12.3¢ /productive Cu-lb 3.6¢ /productive Cu-lb Note) Tonnage of crude ore and Cu precipitate are based on the actual results in 2000

(3) Discussion on profit increase Total profit treating oxide copper ores is expressed as a functional formula as below.

Profit = ∑[{Cap.×A/100×B/100×(100-C)/100×D/100×E/100}(100-F)/100×G] : Sum of each lot

3-8 Here, Cap. : Installed treatment capacity (ton/month or ton/year) A : Rate of cap. utilization (%) B : Soluble Cu (%) in crude ore C : Rate of handling losses (%) D : Recovery rate of Cu (%) in leaching step E : Rate of Cu precipitation (reduction) (%) F : Rate of waste time (%) G : Income received from ENAMI 1) Cap. : Installed capacity for oxide copper ores (ton/month or ton/year) ① Problem 1 : Increase of production scale or installed capacity greatly contributes to reduction in unit cost. ② Study 1 : Possibility of mass production, that is, increase in throughput ③ Result 1 : After 1998, when copper price is below 80¢ /lb, ore supply from outside has been at lower level. Increase is unlikely. ④ Measures 1 : Little expectation to increase in ore supply. Would be difficult even if ENAMI sets about mining operation by itself. ⑤ Target 1 : Increase of plant capacity is unlikely. 2) A : Rate of capacity utilization ① Problem 2 : The most important is maintaining higher level of capacity use. ② Study 2 : Increase of capacity use, that is, reliable ore supply. ③ Results 2 : As stated above, increase of ore supply is difficult. Ore suppliers are all small or medium size and out of ENAMI’s control. Their production strongly correlates with Cu price, which has been lower since 1998. The rate of capacity use in Ovalle has been as low as around 40%. Relation of actual treatment of oxide ores after 1994 and the market price of Cu is illustrated in the following Tables and a Figure. ・ Table 3-13 : Rate of Capacity Use and Corresponding Cu price (1994～2000) ・ Table 3-14 : Market Price of Cu : LME grade A spot sale (1994～ 2001) ・ Figure 3-4 : Rate of capacity use and corresponding Cu price (1994 ～2000) These correlation is summarized in Table 3-15.

Table 3-15 Summary of Correlation between Capacity Use and Copper Price Cu metal price(*2)¢ /lb RCU (Rate of capacity utilization)(*3) % Period Price Range Ave. < 50 50～80 80～100 100 < Ave. 94.01～ Total 82～ 10 months 18 months 18 months 1 month 70.6 High 111.9 97.11 47 months 140 [21 %] [38 %] [38 %] [2 %] [100 %] 97.12～ Total 63～ 27 months 9 months 1 month 0 month 40.2 Low 76.3 00.12 37 months 89 [73 %] [24 %] [3 %] [0 %] [100 %] Note *2 : LME Grade A Settlement *3 : Percentages in [ ] are shown to be proportion of number of months during the period.

3-9 As seen from these data, strong link can be observed between the rate of capacity utilization and Cu price. During the period of higher Cu price (from Jan., 1994 to Nov., 1996 : over 82¢ /lb, averaged about 112¢ /lb), the rate of capacity use recorded 70%, usual lower limit, though under 50% sometimes appeared. On the other hand, during the lower price period (from Dec.,1996 to Dec., 2000 : below 89¢ /lb, averaged about 76¢ /lb), the rate went down to averaged 40.2%. Over 80% of capacity use are counted as few as 3% of total. Many cases are less than 50%, thus even half utilization of capacity were hardly realized. Especially throughout the year 2000, the rate was as low as 25.2%. Oxide ores are generally more difficult to purchase than sulfide. When the price is over 80～90¢ /lb, ores can be obtained comparatively easily, while hardly obtained if the price falls below this range. In the year 2000, however, waste rocks from the primary leaching stage were fed to the secondary stage for more treatment. If these were included, the rate might have been over 50% level. Additionally, it is supposed that the maximum rate seems 57% (max. throughput 8,000ton/month) and the average 43% (throughput 6,000ton/month) as of Jan., 2002, ④ Measure 2 : Increase in the rate of capacity use and succeeding decrease in unit cost as well as stable increase of profit should be aimed. Secondary leaching of the waste rocks is to be discussed for stabilizing operation. Also some premium or incentive system between purchase price of ENAMI and operation costs born by the suppliers is to be discussed along with expansion of loan, technical support for cost saving and others. Any change in the Articles of Association should be needed to allow ENAMI itself to perform exploration and mining activity. Incentives in ore purchase are now partly put into practice for increase of crude ores. ⑤ Target 2 : The rate of capacity use should be stably increased up to 90% (14,000 × 90%=12,600ton/month) from 25.2 %in 2000 (1994～2000, 25.2～85.0%, averaged 57.2%). For this target, stable copper price range of 80～90¢ /lb and further incentives, if possible, as well as the secondary leaching operation are inevitable. 3) B (Soluble Cu grade in crude ores) ① Problem 3 : If the unit operation cost can be reduced at Ovalle plant, it is possible to lower cut-off point for the supplying mines and to increase their reserves allowing more flexible mining as well as increase of monthly output. ② Study 3 : By reducing the unit cost, Cu cut-off grade may be lowered. ③ Results 3 : Recent Cu grade ranges 1.9~2.3% (1994~2000). At present, reduction

3-10 in unit cost and cut-off grade are being proceeded. ④ Measures 3 : Further decrease in cut-off grade is needed. In case of oxide ores, only soluble Cu contributes to the recovery. So attention should be paid to keep primary sulfide Cu, especially chalcopyrite, from mixing into crude ores. It should also be noticed that secondary copper ores can be leached with help of bacteria or strong oxidizing reagents as stated in 5)-4. ⑤ Target 3 : To decrease Cu grade in crude ores down to around 1% by cost reduction. Monthly lowest grade in 2000 reported 2.1% (1.4~2.8%, 1994~2000 ). 4) C (Rate of handling losses) As shown in Loss 1, indicated in Table 3-5~11, handling losses in crushing, agglomeration and leaching sections are totally counted around 1% of total Cu content. Likewise, as shown in Loss 2 in the Table, loss in precipitation section is about 0.05% of total Cu. 4)-1 Dust losses : loss 1 ① Problem 4 : Dust is rising at many points around the crushers, stockpiles before agglomeration, conveyor shoots, loading sites and the like. Accordingly, prevention of these dusts may lead to the improvement of Cu recovery. If fine particles in the ore can be separated ahead of the crushing circuit and treated effectively, that will contribute not only to reduce Cu losses but to prevent channeling in heap leaching process. Naturally it also contributes to keep clean atmosphere. ② Study 4 : To decrease dust rising ③ Results 4 : At present, dust rises much less than before because of water showering. ④ Measure 4 : Further reduction in dust rising and separation and wet treatment of fine particles(*4) are to be studied in future. In that case, assessment of crude ore by lot sampling is to be discussed separately. *4 : primary slime ore at reception and secondary from the crusher ⑤ Target 4 : To reduce those losses down to 0.5% from recent 1.0% in 2000. 4)-2 Leached (pregnant) solution etc. ① Problem 5 : Solution loss at leaching site ② Study 5 : Prevention of solution penetration into the soil ③ Results 5 : Penetration is now completely prevented with HDPE (high density polyethylene) sheets at the bottom and the sides. Very little loss adhered to waste rocks can not be prevented. ④ Measure 5 : Continuous works of HDPE lining at the bottom ⑤ Target 5 : To keep the loss as little as possible 4)-3 Cu precipitate ① Problem 6 : Losses from precipitation, sunlight drying and loading site ② Study 6 : Prevention of losses from precipitation, drying and loading

3-11 ③ Results 6 : Losses are now very little by means of complete washing, windbreak at the drying site etc. ④ Measure 6 : Continuous works of washing etc. ⑤ Target 6 : Cu losses 2 should be kept as low as 0.05% of total quantity. 4)-4 Waste solution from leaching step ① Problem 7 : Until now, waste solution has been accumulated in the pond for evaporation and thus contained Cu was lost as operation loss. ② Study 7 : Recovery of Cu from the solution ③ Results 7 : Cu has not been recovered until now. ④ Measure 7 : Waste solution shall be returned to the leaching step after treated at the model plant. Untreated (excess) solution shall also be returned. Recovery of Cu is expected to rise. This has been done since last autumn (2000) for trial. But in a long term, attention should be paid in accumulation of heavy metals and balance of solution volume. ⑤ Target 7 : Increase in Cu recovery by 3.1% (until now 0%). Cu distribution in the waste solution was accounted for 4.1% in 2000 (2.9 ～4.1%, 1994～2000, averaged 3.8%). 5) D (Cu recovery in leaching step) 5)-1 Composing minerals : Targets to be leached are oxide minerals.

① Copper minerals Chrysocolla CuSiO3・nH2O

Malachite CuCO3・Cu(OH)2 (Chalcopyrite is no target) ② Gangue minerals Limonite, mainly Goethite（α-FeO(OH)）

Magnetite FeO・Fe2O3

Hematite Fe2 O 3

Calcite CaCO3

Quartz SiO2

Gypsum CaSO4・2H2O 3+ Epidote Ca2(Al,Fe )3[OH|O|SiO4|Si2O7] 5)-2 Recovery of Au, Ag ① Problem 8 : Not recovered by acid leaching method. ② Study 8 : Possibility of Au, Ag recovery contained in oxide Cu ores Possible process as follows. a) Leaching with cyanide : Acid leached waste is further ground as fine as necessary then leached with cyanide. b) Segregation method : Oxides are heated up to about 740℃ with NaCl. Cu is volatilized with chlorine gas to form chloride Cu and then reduced with carbon to metallic. Finally, recovered by flotation. c) Flotation : In case of chrysocolla, Cu (Au, Ag) is recovered by

flotation with help of sulphurizing reagents, like Na2S or NaHS.

3-12 Otherwise, Au and Ag are recovered by Aero Promoter 400 series collector along with copper minerals. ③ Results 8 : When Au is over 0.3g/t in crude ore, it is now treated separately as gold ore to recover Au. ④ Measure 8 : Necessary to know how much Au and Ag are contained in crude ores. ⑤ Target 8 : Recovery of Au, Ag in oxide ores is to be studied. 5)-3 Cu recovery rate in leaching process ① Problem 9 : Improvement of operation in leaching step ② Study 9 : Study on leaching rate for each Cu mineral ③ Results 9 : Basic leaching rates are already known by column tests on major mines. ④ Measure 9 : Since composing minerals of each crude ore might vary in the long term, it is necessary to know native leaching rate of each mineral through basic laboratory tests(*5) . *5 : Basic leaching tests Factor ・ 3 types at least : oxides (chrysocolla, malachite etc.), primary sulfides (chalcopyrite etc.), secondary sulfides (chalcocite, covellite etc.) ・ Size : 3 levels, coarse (column type), medium (column), and fine (mechanical agitation) ・ Bacteria (Thiobacillus ferroxidans etc.) : 2 levels, with or without bacteria ・ Leaching time : several levels [coarse size (up to one- half month), medium (up to one-half month) and fine (up to 72 hours)] Results : Leaching curves of each Cu mineral group showing the relation between leached rate vs. leaching hours. Advantage : Possible to know leaching rate of each purchased lot by weighted average of component Cu minerals. This contributes to improvement of leaching results and operation control. ⑤ Target 9 : Improvement of total leaching recovery up to 86.3% from 82.2% in 2000 (60.3～82.2%, from 1994 to 2000, averaged 76.7%). Increase in recovery by 3.1% through item 4)-4 and additional 1.0% through 5)-3 and 5)-4. 5)-4 Leaching recovery rate for sulfide ores ① Problem 10 : If primary or secondary sulfide Cu minerals are contained in crude ore, recovery by acid leaching is decreased in proportion to content of these minerals. Primary sulfide minerals are hardly leached with acid even with help of bacteria activity. Secondary minerals can be leached to a certain extent with bacteria. Sulfide minerals shall be tested with use of

3-13 remained bacteria and Fe3+ (*6) *6 : After treated at the model plant, iron is oxidized to Fe3+that is effective for leaching of Cu sulfide minerals. For example : 0 CuFeS2 + 2Fe2(SO4 )3 [aq] = CuSO4[aq] +5FeSO4[aq] + 2S ② Study 10 : For primary Cu minerals ・ Previous elimination at mine site ・ Effective utilization of strong oxidizing agents like Fe3+ For secondary Cu minerals ・ Previous elimination at mine site ・ Effective utilization of iron-oxidizing bacteria, Fe3+ ③ Results 10 : Currently, bacteria is not positively applied at Ovalle. ④ Measure 10 : Effective use of bacteria should be tried to sulfide ores observing the content of sulfide Cu minerals in each ore lot. At this moment, partial utilization of iron oxidizing bacteria, which have been cultured and used at the model plant, is strongly recommended. ⑤ Target 10 : Improvement of leaching recovery by around 1%. 5)-5 Calcite content ① Problem 11 : When calcite is contained in crude ore, acid consumption is wastefully increased in proportion of the content. Addition of acid, if not controlled carefully, could be below the requisite level for Cu leaching. ② Study 11 : Previous elimination at mine site and control of acid addition. ③ Results 11 : Automatic control of acid addition has been put into practice. ④ Measure 11 : Further elimination and acid control shall be carried out. ⑤ Target 11 : Prevention of decrease in leaching recovery, while keeping acid consumption minimum. 5)-6 Particle size control ① Problem 12 : Suitable particle size for leaching operation ② Study 12 : Crushing conditions (crusher setting, discharge screen opening etc.)and product size. Separate treatment of fine particles.

③ Results 12 : At present, the most suitable size (P80 = -3/8 inch.) is adopted. separate treatment of fines had been suspended for long due to dissatisfactory results. ・ Agitation leaching has been suspended since 1996 ・ Percolation leaching has also been suspended since 1998. ④ Measure 12 : Utilization of leaching curves on each particle size fraction. Review of separate leaching of fines. ⑤ Target 12 : Further study on leaching rate of each size fraction 5)-7 Uniformity of heaped ore ① Problem 13 : If ores are heaped more homogeneously, leaching conditions can be constant and more stabilized results are obtained.

3-14 ② Study 13 : Blending of crude ore before or after crushing. ③ Results 13 : Blending is not practiced before crushing due to difficulty of evaluation (quantity and quality). ④ Measure 13 : Study on blending after crushing. ⑤ Target 13 : Continuous study of blending effect on leaching results. 5)-8 Agglomeration and acid curing ① Problem 14 : Most suitable agglomeration and curing ② Study 14 : Most suitable conditions of acid, water addition, addition method, temperature and others. ③ Results 14 : Currently, operation is well underway. In heap leaching process, it is necessary to keep total surface area per unit weight as large as possible. Generally, ores are crushed minus 3/8 or 1/4 inches but on the other hand, a large quantity of fines may be produced, which cause much problems in later step like channeling and others. To avoid this problem, agglomeration is usually carried out. Also agglomerated particles wear some permeability, which improves dissolution of copper and keeps fines from flowing away. ④ Measure 14 : Further study towards the most suitable operation. ⑤ Target 14 : Improvement of leaching through agglomeration and curing. 5)-9 Heap leaching ① Problem 15 : Most suitable operation ② Study 15 : Most suitable procedures for heaping, working cycle, primary and secondary leaching, sprinkling method of solvent solution, leaching flow, utilization of bacteria, prevention of channeling, influence of rainfall and comparison with other methods etc. ③ Results 15 : Currently, the operation is well under way. ④ Measure 15 : Secondary leaching is to be discussed on the waste rocks from primary circuit to stabilize the operation. Refer to item 2). Positive utilization of bacteria or strong oxidizing agents. Refer to 5)-4. Study on other methods than heap leaching, that is, in-situ, rubble, dump, percolation, agitation leaching and others. ⑤ Target 15 : Continuous study for improvement of Cu recovery. 6) E (Cu precipitation rate exchanging for Fe) 6)-1 Cu precipitation rate ① Problem 16 : Most suitable operation ② Study 16 : Most suitable conditions of iron quantity, reaction time, and others (solvent pH, agitation, temperature, Cu concentration, iron quality etc.) ③ Results 16 : Precipitation rate is as high as 95%, however, distribution of copper in waste solution has been 2.9～4.1%, averaged 3.8% (1994 –2000), which is not good enough.

3-15 ④ Measure 16 : More suitable conditions are to be studied. ⑤ Target 16 : Up to 95% of Cu precipitation rate from 94.9% in 2000. 6)-2 Cu grade in precipitate ① Problem 17 : Most suitable Cu grade ② Study 17 : Most suitable operation balancing Cu grade and recovery. ③ Results 17 : At present the operation is well under way. ④ Measure 17 : Further suitable conditions are to be searched. Dewatering of the precipitate should be done as soon as possible to avoid grade decrease due to oxidation. Removal of Fe is to be studied with help of magnetic separation. ⑤ Target 17 : To keep 83% of Cu grade up from 82.9% in 2000 (75.3～82.9%, averaged 78.3%, 1994～2000). 7) F (Rate of waste time) ① Problem 18 : Decrease of waste time ② Study 18 : Prevention of break due to shortage of crude ores ・ Prevention of mechanical troubles ・ Prevention of human accident ・ Prevention of labor dispute ③ Results 18 : Ore shortage is now a serious problem resulting in decrease in capacity utilization rate. This has been caused either by lower Cu price or long term vacation for suppliers or both. : Refer to item 2). Other items have been satisfactory. ④ Measure 18 : Further decrease in waste time should be achieved. ⑤ Target 18 : Improvement of capacity utilization rate by preventing ore shortage. Refer to item 2). 8) G (Income received from ENAMI management) ① Problem 19 : Improvement in profits (income – expenditure) by increase of income. Income from oxide ore processing is expressed as follows. Net income at Ovalle plant = commissions (ore procurement + crushing + agglomeration, leaching, precipitation) + profit from Cu precipitate valuation +other items. Thus, income of Ovalle plant is composed of above commissions, Cu precipitate valuation, which is difference between actual valuation and predetermined standards of the precipitate (refer to

Chap. 6 in details) and other income items (new product like CuSO4).

At this discussion, production of CuSO4 is not considered as it is still in pilot stage. ② Study 19 : Increase in throughput amount ・ Improvement of Cu recovery rate and Cu grade of precipitate ③ Results 19 : Income from oxide ore processing is estimated as follows. ・ Based on the actual production in 2000

3-16 Y = US$ 654,485 /year ・ Target (to be set) throughout a year Total throughput = installed capacity (168,000tons/year)× operating rate (90%) = 151,200 tons/year X1 = US$ 2,611,519/ year ・ Based upon the maximum level achieved under current situation Total throughput = installed capacity (168,000tons/year)× recent operation rate (57%) = 96,000tons/ year X2 = US$ 1,657,461/ year ④ Measure 19 : Further increase of ore throughput, improvement in Cu recovery and grade. ⑤ Target 19 : Continuous study including current and future production program (4) Cost Saving Total operation cost should be decreased. Currently, reduction of unit cost (US$/ton of crude ore or ¢ /Cu-lb produced) is important. As an over-all target, 5% of reduction should be achieved. US$ 22.14/ton of crude ore , down from US$23.31/ton in 2000 (from MEMORIA ANNUAL 2000 : ENAMI) or 55.6¢ /Cu-lb, down from 60.4¢ /Cu-lb in 2000. 1) Manpower saving ① Problem 20 : Optimization of organization as well as personnel ② Study 20 : Reconsideration along with current and future operation program ③ Results 20 : Reduction plan is now under way with the program. Number of persons : 147(1997), 77 (1998) and 69 (1999) ④ Measure 20 : Further discussion ⑤ Target 20 : Continuous study 2) Energy saving ① Problem 21 : Optimization of operation efficiency : reduction of energy consumption like electric power, fuels etc. ② Study 21 : Full utilization of installed capacity reviewing current process. ③ Results 21 : Full use of capacity or intensive (increase of throughput per hour) operation to reduce energy is now under way. ④ Measure 21 : Continuation of intensive operation for reduction of energy. ⑤ Target 21 : Continuous study 3) Material saving ① Problem 22 : Optimum operation efficiency to minimize consumption of acid, scrap iron, liners and others. ② Study 22 : Full use of installed capacity, process review and adoption of anti-abrasion materials etc. ③ Results 22 : Intensive operation, above-mentioned 2), for reduction of material consumption and adoption of anti-abrasion are now under way.

3-17 ④ Measure 22 : Intensive operation shall be continued. Adoption of anti-abrasion materials may result in reduction of manpower and time as well as material saving. ⑤ Target 22 : Continuous discussion (5) Other discussion 1) Processing methods for oxide Cu ores ① Problem 23 : Most profitable method ② Study 23 : Study of “Solvent extraction (SX-EW) method producing cathode Cu comparing to traditional Cu precipitation. ③ Results 23 : As can be seen in Table 3-4, comparison of direct cost(*7), in item 3.2.1, operation cost by precipitation method is much higher than SX-EW and disadvantageous. However, in case of medium scale operation like Ovalle plant, Cu precipitation method is still advantageous because of severe depreciation cost for SX-EW method, which accompanies a large amount of investment. *7 : Comparison of total direct cost (standard) Oxide Copper Cementation : Underground mining 70～90¢ /lb

SX-EW : Surface mining 30～50¢ /lb

Sulphide Copper Smelting : Underground mining 40～60¢ /lb

: Surface mining 50～70¢ /lb ④ Measure 23 : In future, SX-EW process should also be discussed if oxide ores are fully supplied and large scale operation is realized. ⑤ Target 23 : Study to be continued. 2) Processing of leached (pregnant) solution ① Problem 24 : Cu precipitation method is not fully profitable and is inevitably accompanied with pollution problem brought by waste solution. ② Study 24 : Discussion of other process than precipitation or SX-EW.

③ Results 24 : Currently, production of CuSO4・5H2O is being carried out at a new pilot plant.

④ Measure 24 : Long term market research should be done on demand of CuSO4 followed by feasibility study. Also sales of the pregnant solution should be studied to other mines or plants employing SX-EW process. ⑤ Target 24 : Study to be continued. 3) Treatment of waste solution from leaching step ① Problem 25 : Prevention of pollution is inevitable. ② Study 25 : Discussion of alternative process other than solution treatment. ③ Results 25 : Prevention of pollution is now achieved partly on the waste solution (around 100m3/day) through the Model Plant installed during this Study.

3-18 Through this treatment, industrial water can be saved because the treated solution is returned to the leaching step for reuse. As for the excess solution, discussion shall be needed (Refer to Chap. 7 in this Report). ④ Measure 25 : Excess (untreated) solution, 200～300m3/day, shall be returned to the leaching step along with the treated solution from the Model Plant.

Also possible utilization of hematite (Fe2O3), ferrite (FeO・Fe2O3), ferrous or ferric sulfate from the solution shall be studied. ⑤ Target 25 : Study to be continued. (6) Summary Table 3-16 summarizes the above-mentioned results or targets for oxide Cu ore processing. ・ Improvement 1 : Increase of income ① Increase in capacity use rate : Up from 25.2% [Y] in 2000 to 90.0%, an annual target

Actual result was maximum 57.1% [X2] (Measure) Further increase of incentives for ore suppliers Mine management by ENAMI itself. Decrease in Cu cut-off grade of crude ores. Constant operation of secondary leaching of primary waste rocks. Expectation of Cu price hike over 80～90 ¢ /lb etc.

② Increase of total Cu recovery : Up from 77.3% [Y] in 2000 to 81.5%[X1], as a target.

Actual result was maximum 81.5%[X2]. (Measure) Decrease of Cu losses (Prevention of dust rising, wet treatment of fine particles etc.) Increase of Cu recovery in leaching step (optimization of particle size, reuse of waste and treated solution, utilization of bacteria etc.) Increase of Cu precipitation rate (by further control).

③ Grade of Cu precipitate : Up from 82.9% [Y] in 2000 to 83.0% as annual target[X1].

Actual result was maximum 83.0% [X2] so far. (Measure) Further control needed. ・ Improvement 2 : Cost saving : Down from US$ 23.31/ton [Y] in 2000 to

US$ 22.14/ton [X1] as an annual target. The best result was

US$22.14/ ton [X2] so far. (Measure) Cut down by 5% in every item. With all these improvement, possible increase in operation profit was estimated in three

cases, that is, annual target [X1] (ore throughput = installed capacity (168,000t/year)×

utilization rate 90% = 151,200t/year), the maximum of actual results [X2] (throughput = 168,000t/year × utilization rate 57% =96,000t/year) and average result throughout 2000 [Y] (throughput = 42,365t/year). The increase of the profit should be the difference of each

case , [X1-Y] and [X2-Y] respectively. In the estimate, production of CuSO4・5H2O and waste solution treatment are excluded. Regard to the gross profit, even if the increase in the rate of capacity use was achieved up to about 90% with realization of above mentioned improvements, Ovalle operation still stays

3-19 in the red. As described in the Table, US$ 735,949/year of deficit (A-B in the Table) in the case of

annual target [X1] and also US$ 467,979/year in the case of the actual maximum [X2] are respectively expected. Numerical values in the parentheses show the results without technical improvements. This concludes that US$ 452,676/year of increase in gross profit in the case of annual target

[X1] and US$ 286,704/year in the case of the actual maximum [X2] are expected by achieving the above improvements.

Summary of the Discussion on Gross Profit for Oxide Cu Processing (US$/year) Annual Target Actual Max. Year 2000 Difference Difference

[X1] [X2] [Y] [X1-Y] [X2－Y] Processing ore 151,200 96,000 42,365 (t/year) Sales amount 2,611,519 1,657,461 654,485 +1,957,034 +1,002,976 [A] (2,335,846) (1,483,077) (+1,681,361) (+828,592)

Production 3,347,568 2,125,440 987,528 +2,360,040 +1,137,912 cost [B] (3,524,471) (2,237,760) (+2,536,943) (+1,250,232)

-735,949 -467,979 -333,043 -402,906 -134,936 Profit [A－B] (-1,188,625) (-754,683) (-855,582) (-421,640) <+286,704> improvement>

3-20 Run-of-mine ore: Oxide copper ore 42,365 dry t (Ore distribution 100.0%) 2.26 soluble Cu-% 959.4 Cu-t (Cu distribution 100.0) Crushing *1, *2

H2SO4 Agglomeration *2

H2SO4 solution Leaching *2

Solution Waste ore 40,161 dry t (Ore distribution 94.8%) 0.41 Cu-% 169.0 Cu-t (Cu distribution 17.6%)

Scrap iron Precipitation Cu precipitation rate 94.9% *3

Precipitate Waste solution 39.0 Cu-t Filtering (Cu distribution 4.1%)

Copper Precipitate Evaporation pond Waste solution treatment : Cement Copper [old] now stopped [new] now operated 894 dry t (Ore distribution 2.1%) 82.9 Cu-% Sludge Treated 741.5 Cu-t (Cu distribution 77.3%) solution Cu recovery 77.3% Final disposal : deposition

Figure 3-2 Block Diagram(outline) with Material Balance for Oxide Copper Ore in 2000 Ovalle Plant, ENAMI Note *1: Every lot for reception ore should be weighed, sampled and analyzed at reception and crushing sections to decide commercial condition to buy ore. *2: Loss in Crushing, Agglomeration and Leaching sections 424 dry t (Ore distribution 1.0%) 2.24 Cu-% 9.5 Cu-t (Cu distribution 1.0%) *3: Loss in Precipitation section 0.5 Cu-t (Cu distribution 0.1%)

3-21 Run-of-mine ore: Oxide copper ore

1.Truck scale

2.Crude ore stockyard

3.Crude ore bin

4.Classifying

Coarse(+) Fine(-)

5.Primary crushing

6.Classifying

Coarse(+) Fine(-)

（ 7.Secondary crushing ）

（ 8.Classifying ）

Coarse(+) Fine(-)

9.Tertiary crushing

10.Sampling

11.Crushed ore stockyard

H2SO4 12.Agglomeration

H2SO4 solution 13.Primary leaching: Heap leaching

[Test production] Leaching solution: pregnant solution Waste ore Scrap iron No treated waste solution 14.Primary precipitation 21.Socondary leaching: Dump leaching 22.Copper sulfate production 15.Solid/liquid separation Intermediate solution Waste ore Copper sulfate Sludge Water

16.Solid/liquid separation: Filtering

Cake Filtrate Scrap iron 17.Drying 18.Secondary precipitation and solid/liquid separation

Copper precipitate Sludge Waste solution : Cement copper 19.[Old] Evaporation pond 19.[New] Waste solution treatment : now stopped : now operated after Sep., 2001

Sludge Treated solution

20.Final disposal : deposition

Figure 3-3 Block Diagram for Oxide Copper Ore: Ovalle Plant, ENAMI

3-22

（Figure 3-3） Equipment for Oxide Ore: Ovalle plant, ENAMI No. Process Equipment and specification Remarks 1 Weighing Truck scale Every lot of crude ore Crude ore particle size 2 Crude ore stockyard : -7” 3 Coarse ore bin Every lot of crude ore 4 Classifying Fixed screen, Grizzly (opening 2･1/2”), 1unit Gyratory crusher：Trylor, TY-1398F type, 3’φ, 50t/h, 5 Primary crushing 1 unit (spare circuit：Single Toggle Crusher, 1 unit) 6 Classifying Vibrating screen (opening 3/4”), 1 unit 7 Secondary crushing Cone crusher：Symons, SH type, 3’φ, 50t/h, 1 unit Abbreviated 8 Classifying Vibrating screen (opening 1/4”), 1 unit according to case 9 Tertiary crushing Cone crusher：Symons, SH type, 3’φ, 50t/h, 1 unit 10 Sampling Automatic sampling → analysis Every lot of crude ore 11 Crushed ore stockyard Rotary agglomerator：7mφ×5.4mL, Rubber lining, Acid cure, leaching 12 Agglomeration 1unit particle size: -3/8” Primary leaching Heap leaching pad：40mW×90mL×2～2.2mH, 1unit 13 20～25days/cycle : Heap leaching ＋40mW×40mL×2～2.2mH, 1unit Rotary precipitator：Drum type, 120”φ×130”L, 1unit 14 Primary precipitation ＋84”φ×96”L, 3units 15 Solid/liquid separation Precipitation decantor, 1unit Solid/liquid separation 16 Pan filter：Vacuum type, 1mW×1.5mL, 2units : Filtering 17 Drying Sunlight drying Secondary precipitation 18 Precipitation box, 1unit (6 boxes) and solid/liquid separation [New] Waste solution Model plant for waste solution treatment [Old] 19 treatment ：100m3/day, 1unit Evaporation pond 20 Final disposal: deposition Secondary leaching Dump leaching pad：110mW×60mL×Max.35mH, 21 : Dump leaching 1unit Test plant for production of copper sulfate 22 Copper sulfate production ：40t/month, 1unit

3-23

/lb) ( price metal Cu ¢

160 140 120 100 80 60 40 20 0

/lb) 0

¢ u J

Cu metal price( n a

l Time

RCU(%)

Cu metal price:LME Grade A Settlement u J

RCU:Rate of capacity utilization

u J

for Oxide Copper Ore and Cu Metal Price 5

RCU - n

0 n Figure 3-4 Relation between RCU(Rate of Capacity Utilization) a

80 60 40 20 J

160 140 120 100

copper ore copper RCU (%) for oxide for (%) RCU

3-24 Table 3-4 Comparison among Processing Methods for Copper Ores Oxide Copper Ore Sulfide Copper Ore Chrysocolla CuSiO ･nH O、 Chalcopyrite CuFeS 、 1. Object Copper Ore 3 2 2 Malachite CuCO ･Cu(OH) , etc. Chalcocite Cu S、 : Major Minerals 3 2 2 Note: It could be possible to leach secondary sulfide minerals- Covelline/Covellite CuS, etc. namely, Chalcocite, Covelline/Covellite, etc., too, with bacteria. Precipitation (Cementation)- SX-EW(Solvent extraction and Mineral processing-Smelting 2. Method of Production Smelting process Electro-winning) process process Mining Mining Mining

Run-of-mine ore (Crude ore) Run-of-mine ore (Crude ore) Run-of-mine ore (Crude ore)

Crushing Crushing Crushing Agglomeration Agglomeration Grinding Mineral Leaching Leaching Flotation processing Precipitation Solvent extraction Hydro- copper) Electro-winning metallurgy Copper concentrate 3. Production Flow Copper precipitate (Cement Cu= about 25～40% Cu= about 75～85% Electrolytic Copper Smelting Pyro- Smelting Pyro- : Cathode Copper Conversion metallurgy Conversion metallurgy Cu≧ about 99.97% Electro-refining Electro-refining Electrolytic Copper Electrolytic Copper : Cathode Copper : Cathode Copper Cu≧ about 99.97% Cu≧ about 99.97% 4. Possibility of Au, Ag Recovery × × ○ 5. Direct Cost (*1) 5-1 Mining ･Open pit (A) ¢ /lb 9～45, Ave. about 24 ○ $/t 0.5～1.9, Ave. about 1 ･Underground (B) ¢ /lb 11～97, Ave.about 38 ○ $/t 2～30, Ave.about 12 5-2 Mineral Processing ･Ore of (A) ¢ /lb ○：Crush., Agglo., Leach. 5～67, Ave. about 24 $/t 1.5～5.5, Ave. about 3 ･Ore of (B) ¢ /lb ○: Crushing, Agglomeration, 6～27, Ave.about 14 $/t Leaching, Precipitation 2～15, Ave.about 5 5-3 Transportation ¢ /lb ○: Cu precipitate 0.5～8, Ave.about 3: Cu conc. 5-4 Smelting, etc. ･Pyrometallurgy ¢ /lb ○ 8～32, Ave.about 19 ･Hydrometallurgy ¢ /lb ○ 5-5 By-product ¢ /lb -1～-130, Ave.about –22 (Au, Ag, Mo) Direct Cost Total (certain degree) ･Ore of (A) ¢ /lb about 30～50 about 40～60 ･Ore of (B) ¢ /lb about 70～90 about 50～70 6. Applied Scale Small (to middle) Big (*2) Small to big Note *1: Total cost is composed of the direct cost, interest, depreciation, etc.., *2: In case of smaller scale, it goes to be impossible to conduct depreciation for solvent extraction and electro-winning facilities according to a smaller quantity of run-of-mine ore.

3-25 Table 3-5 Result of processing for oxide copper ore in 1994 at Ovalle plant, ENAMI *1: RCU Rate of capacity utilization(Cap.: 14,000t/month: 168,000t/year) Year Process Product Month Ore Tonnage Cu t distribut.% RCU*1 % grade % t distribut.% leach rate % preci.rate % 1994 Crushing, Run-of-mine ore A → January 10,017 100.0 71.6 2.1 207.5 100.0 Agglomeration B, C, D February 12,593 100.0 90.0 2.0 256.4 100.0 March 13,145 100.0 93.9 2.1 278.3 100.0 April 15,425 100.0 110.2 2.1 329.9 100.0 May 12,346 100.0 88.2 2.1 262.4 100.0 June 12,094 100.0 86.4 2.1 253.5 100.0 July 11,867 100.0 84.8 2.1 249.9 100.0 August 10,191 100.0 72.8 2.1 215.9 100.0 September 12,478 100.0 89.1 2.1 262.4 100.0 October 10,615 100.0 75.8 2.2 230.0 100.0 November 11,766 100.0 84.0 2.1 248.9 100.0 December 10,294 100.0 73.5 2.3 237.5 100.0 Total 142,831 100.0 85.0 2.1 3,033 100.0 Crushing, Loss 1 B January 100 1.0 2.2 2.2 1.1 Agglomeration, : Ore distribution February 126 1.0 1.6 2.1 0.8 Leaching ＝ 1.0% March 131 1.0 1.9 2.5 0.9 April 154 1.0 2.0 3.1 0.9 May 123 1.0 1.7 2.1 0.8 June 121 1.0 1.7 2.1 0.8 July 119 1.0 1.7 2.0 0.8 August 102 1.0 2.0 2.1 1.0 September 125 1.0 2.4 3.0 1.1 October 106 1.0 1.9 2.0 0.9 November 118 1.0 1.7 2.0 0.8 December 103 1.0 2.0 2.0 0.9 Total 1,428 1.0 1.9 27 0.9 Leaching Solution C → January 0.0 116.8 56.3 56.9 E, F, G February 0.0 104.7 40.8 41.2 March 0.0 126.6 45.5 45.9 April 0.0 173.4 52.6 53.1 May 0.0 251.3 95.8 96.5 June 0.0 59.5 23.5 23.7 July 0.0 191.8 76.7 77.4 August 0.0 144.4 66.9 67.5 September 0.0 138.0 52.6 53.2 October 0.0 178.4 77.6 78.2 November 0.0 158.9 63.8 64.4 December 0.0 169.0 71.2 71.8 Total 0.0 1,813 59.8 60.3 Waste ore D January 9,800 97.8 0.9 88.5 42.6 February 12,362 98.2 1.2 149.6 58.4 March 12,887 98.0 1.2 149.3 53.6 April 15,097 97.9 1.0 153.4 46.5 May 11,972 97.0 0.1 9.0 3.4 June 11,913 98.5 1.6 191.9 75.7 July 11,557 97.4 0.5 56.1 22.4 August 9,944 97.6 0.7 69.4 32.2 September 12,215 97.9 1.0 121.5 46.3 October 10,330 97.3 0.5 49.6 21.6 November 11,489 97.6 0.8 88.0 35.4 December 10,022 97.4 0.7 66.4 28.0 Total 139,589 97.7 0.9 1,193 39.3 Precipitation Loss 2 E January 0.0 0.1 0.0 : Cu distribution February 0.0 0.1 0.0 ＝0.05% March 0.0 0.1 0.0 April 0.0 0.2 0.0 May 0.0 0.1 0.0 June 0.0 0.1 0.0 July 0.0 0.1 0.0 August 0.0 0.1 0.0 September 0.0 0.1 0.0 October 0.0 0.1 0.0 November 0.0 0.1 0.0 December 0.0 0.1 0.0 Total 0.0 2 0.0 Precipitate Cu F January 150 1.5 74.0 111.0 53.5 95.0 : Cement copper February 163 1.3 61.1 99.5 38.8 95.0 March 165 1.3 72.9 120.3 43.2 95.0 April 216 1.4 76.4 164.7 49.9 95.0 May 315 2.6 75.7 238.7 91.0 95.0 June 71 0.6 79.2 56.6 22.3 95.0 July 239 2.0 76.2 182.2 72.9 95.0 August 181 1.8 76.0 137.2 63.5 95.0 September 163 1.3 80.4 131.1 49.9 95.0 October 224 2.1 75.5 169.5 73.7 95.0 November 183 1.6 82.7 151.0 60.6 95.0 December 208 2.0 77.0 160.5 67.6 95.0 Total 2,278 1.6 75.6 1,722 56.8 95.0 Waste water G January 0.0 5.7 2.8 February 0.0 5.1 2.0 March 0.0 6.2 2.2 April 0.0 8.5 2.6 May 0.0 12.4 4.7 June 0.0 2.9 1.1 July 0.0 9.5 3.8 August 0.0 7.1 3.3 September 0.0 6.8 2.6 October 0.0 8.8 3.8 November 0.0 7.8 3.1 December 0.0 8.3 3.5 Total 0.0 89 2.9 3-26 Table 3-6 Result of processing for oxide copper ore in 1995 at Ovalle plant, ENAMI *1: RCU Rate of capacity utilization(Cap.: 14,000t/month: 168,000t/year) Year Process Product Month Ore Tonnage Cu t distribut.% RCU*1 % grade % t distribut.% leach rate % preci.rate % 1995 Crushing, Run-of-mine ore A → January 9,764 100.0 69.7 2.3 225.5 100.0 Agglomeration B, C, D February 9,592 100.0 68.5 2.2 208.0 100.0 March 11,165 100.0 79.7 2.2 249.6 100.0 April 10,598 100.0 75.7 2.2 228.4 100.0 May 10,823 100.0 77.3 2.2 237.1 100.0 June 10,420 100.0 74.4 2.2 230.2 100.0 July 10,928 100.0 78.1 2.2 240.2 100.0 August 10,686 100.0 76.3 2.2 239.7 100.0 September 9,925 100.0 70.9 2.3 223.1 100.0 October 10,278 100.0 73.4 2.3 234.7 100.0 November 10,579 100.0 75.6 2.3 240.4 100.0 December 11,598 100.0 82.8 2.2 256.8 100.0 Total 126,356 100.0 75.2 2.2 2,814 100.0 Crushing, Loss 1 B January 98 1.0 2.2 2.2 1.0 Agglomeration, : Ore distribution February 96 1.0 2.0 1.9 0.9 Leaching ＝ 1.0% March 112 1.0 1.8 2.0 0.8 April 106 1.0 1.7 1.8 0.8 May 108 1.0 2.3 2.5 1.0 June 104 1.0 2.2 2.2 1.0 July 109 1.0 2.0 2.2 0.9 August 107 1.0 2.5 2.7 1.1 September 99 1.0 2.1 2.1 0.9 October 103 1.0 2.6 2.7 1.2 November 106 1.0 2.5 2.6 1.1 December 116 1.0 2.6 3.0 1.2 Total 1,264 1.0 2.2 28 1.0 Leaching Solution C → January 0.0 201.2 89.3 90.1 E, F, G February 0.0 180.3 86.7 87.5 March 0.0 215.1 86.2 86.9 April 0.0 188.5 82.5 83.2 May 0.0 205.1 86.5 87.4 June 0.0 160.1 69.6 70.2 July 0.0 190.7 79.4 80.1 August 0.0 177.8 74.2 75.0 September 0.0 150.5 67.4 68.1 October 0.0 204.8 87.2 88.3 November 0.0 183.2 76.2 77.1 December 0.0 214.1 83.4 84.4 Total 0.0 2,271 80.7 81.5 Waste ore D January 9,465 96.9 0.2 22.1 9.8 February 9,316 97.1 0.3 25.8 12.4 March 10,838 97.1 0.3 32.5 13.0 April 10,303 97.2 0.4 38.1 16.7 May 10,510 97.1 0.3 29.6 12.5 June 10,155 97.5 0.7 67.8 29.5 July 10,628 97.3 0.5 47.3 19.7 August 10,401 97.3 0.6 59.2 24.7 September 9,675 97.5 0.7 70.6 31.6 October 9,970 97.0 0.3 27.2 11.6 November 10,290 97.3 0.5 54.5 22.7 December 11,268 97.2 0.4 39.7 15.5 Total 122,821 97.2 0.4 515 18.3 Precipitation Loss 2 E January 0.0 0.1 0.0 : Cu distribution February 0.0 0.1 0.0 ＝0.05% March 0.0 0.1 0.0 April 0.0 0.1 0.0 May 0.0 0.1 0.0 June 0.0 0.1 0.0 July 0.0 0.1 0.0 August 0.0 0.1 0.0 September 0.0 0.1 0.0 October 0.0 0.1 0.0 November 0.0 0.1 0.0 December 0.0 0.1 0.0 Total 0.0 1 0.0 Precipitate Cu F January 262 2.7 73.0 191.2 84.8 95.0 : Cement copper February 225 2.3 76.0 171.2 82.3 94.9 March 277 2.5 73.6 204.3 81.8 94.9 April 242 2.3 74.1 178.9 78.3 94.9 May 258 2.4 75.5 194.7 82.1 94.9 June 190 1.8 80.1 152.0 66.0 94.9 July 214 2.0 84.8 181.0 75.4 94.9 August 243 2.3 69.4 168.8 70.4 94.9 September 177 1.8 80.8 142.9 64.0 94.9 October 272 2.6 71.5 194.4 82.8 94.9 November 229 2.2 76.0 173.9 72.4 94.9 December 275 2.4 73.8 203.2 79.1 94.9 Total 2,863 2.3 75.3 2,156 76.6 94.9 Waste water G January 0.0 9.9 4.4 February 0.0 9.0 4.3 March 0.0 10.8 4.3 April 0.0 9.4 4.1 May 0.0 10.2 4.3 June 0.0 8.0 3.5 July 0.0 9.5 4.0 August 0.0 8.9 3.7 September 0.0 7.5 3.4 October 0.0 10.2 4.4 November 0.0 9.2 3.8 December 0.0 10.7 4.2 Total 0.0 113 4.0 3-27 Table 3-7 Result of processing for oxide copper ore in 1996 at Ovalle plant, ENAMI *1: RCU Rate of capacity utilization(Cap.: 14,000t/month: 168,000t/year) Year Process Product Month Ore Tonnage Cu t distribut.% RCU*1 % grade % t distribut.% leach rate % preci.rate % 1996 Crushing, Run-of-mine ore A → January 12,843 100.0 91.7 2.2 281.5 100.0 Agglomeration B, C, D February 13,644 100.0 97.5 2.3 314.1 100.0 March 12,436 100.0 88.8 2.3 285.6 100.0 April 12,517 100.0 89.4 2.3 292.7 100.0 May 11,322 100.0 80.9 2.2 251.1 100.0 June 12,626 100.0 90.2 2.2 273.8 100.0 July 12,568 100.0 89.8 2.1 265.6 100.0 August 11,662 100.0 83.3 2.3 262.0 100.0 September 11,596 100.0 82.8 2.2 253.3 100.0 October 12,164 100.0 86.9 2.2 261.6 100.0 November 8,232 100.0 58.8 2.2 181.8 100.0 December 6,837 100.0 48.8 2.0 134.4 100.0 Total 138,449 100.0 82.4 2.2 3,058 100.0 Crushing, Loss 1 B January 128 1.0 2.4 3.0 1.1 Agglomeration, : Ore distribution February 136 1.0 2.5 3.4 1.1 Leaching ＝ 1.0% March 124 1.0 2.0 2.5 0.9 April 125 1.0 2.2 2.7 0.9 May 113 1.0 2.0 2.3 0.9 June 126 1.0 2.0 2.6 0.9 July 126 1.0 2.4 3.0 1.1 August 117 1.0 1.9 2.2 0.9 September 116 1.0 2.6 3.0 1.2 October 122 1.0 2.2 2.7 1.0 November 82 1.0 2.1 1.7 0.9 December 68 1.0 1.6 1.1 0.8 Total 1,384 1.0 2.2 30 1.0 Leaching Solution C → January 0.0 223.0 79.2 80.1 E, F, G February 0.0 242.0 77.1 77.9 March 0.0 238.3 83.4 84.1 April 0.0 221.4 75.6 76.4 May 0.0 179.7 71.6 72.2 June 0.0 217.7 79.5 80.3 July 0.0 203.7 76.7 77.6 August 0.0 205.0 78.2 78.9 September 0.0 197.3 77.9 78.9 October 0.0 205.2 78.4 79.3 November 0.0 140.0 77.0 77.8 December 0.0 108.0 80.4 81.0 Total 0.0 2,381 77.9 78.7 Waste ore D January 12,492 97.3 0.4 55.5 19.7 February 13,266 97.2 0.5 68.7 21.9 March 12,073 97.1 0.4 44.9 15.7 April 12,171 97.2 0.6 68.5 23.4 May 11,029 97.4 0.6 69.1 27.5 June 12,282 97.3 0.4 53.5 19.5 July 12,239 97.4 0.5 58.8 22.1 August 11,341 97.2 0.5 54.8 20.9 September 11,283 97.3 0.5 52.9 20.9 October 11,838 97.3 0.5 53.7 20.5 November 8,009 97.3 0.5 40.0 22.0 December 6,661 97.4 0.4 25.3 18.8 Total 134,683 97.3 0.5 646 21.1 Precipitation Loss 2 E January 0.0 0.1 0.0 : Cu distribution February 0.0 0.2 0.0 ＝0.05% March 0.0 0.1 0.0 April 0.0 0.1 0.0 May 0.0 0.1 0.0 June 0.0 0.1 0.0 July 0.0 0.1 0.0 August 0.0 0.1 0.0 September 0.0 0.1 0.0 October 0.0 0.1 0.0 November 0.0 0.0 0.0 December 0.0 0.1 0.0 Total 0.0 1 0.0 Precipitate Cu F January 265 2.1 80.0 211.8 75.2 95.0 : Cement copper February 294 2.2 78.1 229.8 73.2 94.9 March 286 2.3 79.0 226.2 79.2 94.9 April 272 2.2 77.2 210.2 71.8 94.9 May 227 2.0 75.0 170.6 67.9 94.9 June 254 2.0 81.3 206.7 75.5 94.9 July 257 2.0 75.3 193.4 72.8 94.9 August 249 2.1 78.2 194.6 74.3 94.9 September 256 2.2 73.1 187.4 74.0 94.9 October 257 2.1 75.7 194.8 74.5 94.9 November 169 2.1 78.8 133.0 73.2 95.0 December 119 1.7 86.1 102.6 76.3 94.9 Total 2,907 2.1 77.8 2,261 74.0 94.9 Waste water G January 0.0 11.0 3.9 February 0.0 12.1 3.9 March 0.0 11.9 4.2 April 0.0 11.1 3.8 May 0.0 9.0 3.6 June 0.0 10.9 4.0 July 0.0 10.2 3.8 August 0.0 10.2 3.9 September 0.0 9.9 3.9 October 0.0 10.3 3.9 November 0.0 7.0 3.9 December 0.0 5.4 4.0 Total 0.0 119 3.9 3-28 Table 3-8 Result of processing for oxide copper ore in 1997 at Ovalle plant, ENAMI *1: RCU Rate of capacity utilization(Cap.: 14,000t/month: 168,000t/year) Year Process Product Month Ore Tonnage Cu t distribut.% RCU*1 % grade % t distribut.% leach rate % preci.rate % 1997 Crushing, Run-of-mine ore A → January 6,808 100.0 48.6 1.9 128.6 100.0 Agglomeration B, C, D February 4,584 100.0 32.7 2.1 96.5 100.0 March 8,512 100.0 60.8 1.9 160.2 100.0 April 9,888 100.0 70.6 1.4 141.6 100.0 May 5,251 100.0 37.5 2.1 110.6 100.0 June 2,170 100.0 15.5 2.5 53.2 100.0 July 3,585 100.0 25.6 2.2 78.8 100.0 August 4,819 100.0 34.4 2.3 109.4 100.0 September 3,220 100.0 23.0 2.2 72.1 100.0 October 3,669 100.0 26.2 2.1 78.5 100.0 November 4,170 100.0 29.8 2.2 90.3 100.0 December 4,793 100.0 34.2 2.1 100.1 100.0 Total 61,468 100.0 36.6 2.0 1,220 100.0 Crushing, Loss 1 B January 68 1.0 1.8 1.2 1.0 Agglomeration, : Ore distribution February 46 1.0 2.6 1.2 1.2 Leaching ＝ 1.0% March 85 1.0 2.0 1.7 1.1 April 99 1.0 1.7 1.6 1.2 May 53 1.0 1.8 0.9 0.8 June 22 1.0 2.6 0.6 1.1 July 36 1.0 2.1 0.7 0.9 August 48 1.0 2.2 1.1 1.0 September 32 1.0 2.1 0.7 0.9 October 37 1.0 2.0 0.7 0.9 November 42 1.0 1.8 0.8 0.8 December 48 1.0 1.9 0.9 0.9 Total 615 1.0 2.0 12 1.0 Leaching Solution C → January 0.0 99.5 77.4 78.1 E, F, G February 0.0 75.7 78.4 79.4 March 0.0 126.4 78.9 79.8 April 0.0 111.8 79.0 79.9 May 0.0 87.3 78.9 79.6 June 0.0 42.0 78.9 79.8 July 0.0 62.1 78.8 79.5 August 0.0 85.8 78.4 79.2 September 0.0 58.8 81.6 82.4 October 0.0 61.6 78.5 79.3 November 0.0 71.0 78.6 79.3 December 0.0 78.5 78.4 79.1 Total 0.0 960 78.7 79.5 Waste ore D January 6,640 97.5 0.4 27.9 21.7 February 4,462 97.3 0.4 19.6 20.3 March 8,301 97.5 0.4 32.0 20.0 April 9,677 97.9 0.3 28.2 19.9 May 5,111 97.3 0.4 22.4 20.2 June 2,106 97.1 0.5 10.6 20.0 July 3,487 97.3 0.5 16.0 20.3 August 4,685 97.2 0.5 22.6 20.6 September 3,129 97.2 0.4 12.6 17.5 October 3,571 97.3 0.5 16.1 20.5 November 4,057 97.3 0.5 18.6 20.5 December 4,667 97.4 0.4 20.7 20.7 Total 59,893 97.4 0.4 247 20.3 Precipitation Loss 2 E January 0.0 0.1 0.0 : Cu distribution February 0.0 0.0 0.0 ＝0.05% March 0.0 0.1 0.0 April 0.0 0.1 0.0 May 0.0 0.1 0.0 June 0.0 0.0 0.0 July 0.0 0.0 0.0 August 0.0 0.1 0.0 September 0.0 0.0 0.0 October 0.0 0.0 0.0 November 0.0 0.0 0.0 December 0.0 0.1 0.0 Total 0.0 1 0.0 Precipitate Cu F January 126 1.8 75.2 94.5 73.5 95.0 : Cement copper February 86 1.9 83.4 71.9 74.5 94.9 March 156 1.8 76.9 120.0 74.9 94.9 April 138 1.4 76.7 106.2 75.0 94.9 May 108 2.1 77.0 82.9 74.9 94.9 June 51 2.4 77.6 39.9 74.9 94.9 July 77 2.1 77.0 58.9 74.8 94.9 August 105 2.2 77.7 81.4 74.4 94.9 September 71 2.2 78.4 55.8 77.5 94.9 October 74 2.0 79.0 58.5 74.6 94.9 November 80 1.9 83.9 67.4 74.6 94.9 December 94 2.0 79.6 74.5 74.5 94.9 Total 1,166 1.9 78.2 912 74.8 94.9 Waste water G January 0.0 4.9 3.8 February 0.0 3.8 3.9 March 0.0 6.3 3.9 April 0.0 5.6 3.9 May 0.0 4.4 3.9 June 0.0 2.1 3.9 July 0.0 3.1 3.9 August 0.0 4.3 3.9 September 0.0 2.9 4.1 October 0.0 3.1 3.9 November 0.0 3.5 3.9 December 0.0 3.9 3.9 Total 0.0 48 3.9 3-29 Table 3-9 Result of processing for oxide copper ore in 1998 at Ovalle plant, ENAMI *1: RCU Rate of capacity utilization(Cap.: 14,000t/month: 168,000t/year) Year Process Product Month Ore Tonnage Cu t distribut.% RCU*1 % grade % t distribut.% leach rate % preci.rate % 1998 Crushing, Run-of-mine ore A → January 4,425 100.0 31.6 2.0 88.1 100.0 Agglomeration B, C, D February 4,580 100.0 32.7 1.7 79.7 100.0 March 4,927 100.0 35.2 2.0 100.2 100.0 April 3,812 100.0 27.2 1.9 71.0 100.0 May 4,555 100.0 32.5 1.8 80.7 100.0 June 6,495 100.0 46.4 1.7 109.7 100.0 July 5,062 100.0 36.2 2.1 105.6 100.0 August 6,306 100.0 45.0 2.0 124.8 100.0 September 6,525 100.0 46.6 1.9 124.5 100.0 October 7,011 100.0 50.1 1.7 122.3 100.0 November 7,550 100.0 53.9 1.9 145.2 100.0 December 8,216 100.0 58.7 2.1 175.2 100.0 Total 69,465 100.0 41.3 1.9 1,327 100.0 Crushing, Loss 1 B January 44 1.0 2.1 0.9 1.0 Agglomeration, : Ore distribution February 46 1.0 1.7 0.8 1.0 Leaching ＝ 1.0% March 49 1.0 2.5 1.2 1.2 April 38 1.0 2.1 0.8 1.1 May 46 1.0 2.0 0.9 1.1 June 65 1.0 1.6 1.1 1.0 July 51 1.0 1.8 0.9 0.8 August 63 1.0 1.9 1.2 0.9 September 65 1.0 1.8 1.1 0.9 October 70 1.0 2.1 1.5 1.2 November 75 1.0 2.3 1.7 1.2 December 82 1.0 2.4 2.0 1.1 Total 695 1.0 2.0 14 1.1 Leaching Solution C → January 0.0 73.7 83.7 84.5 E, F, G February 0.0 65.2 81.8 82.6 March 0.0 80.7 80.6 81.6 April 0.0 62.7 88.3 89.3 May 0.0 66.1 81.8 82.8 June 0.0 88.5 80.6 81.4 July 0.0 91.2 86.3 87.0 August 0.0 102.3 82.0 82.8 September 0.0 79.8 64.1 64.7 October 0.0 61.7 50.5 51.1 November 0.0 82.0 56.4 57.1 December 0.0 124.8 71.2 72.1 Total 0.0 979 73.7 74.5 Waste ore D January 4,307 97.3 0.3 13.5 15.3 February 4,469 97.6 0.3 13.7 17.2 March 4,797 97.4 0.4 18.3 18.2 April 3,711 97.4 0.2 7.5 10.6 May 4,443 97.5 0.3 13.8 17.0 June 6,342 97.6 0.3 20.2 18.4 July 4,921 97.2 0.3 13.6 12.9 August 6,141 97.4 0.4 21.3 17.1 September 6,380 97.8 0.7 43.6 35.0 October 6,879 98.1 0.9 59.1 48.3 November 7,392 97.9 0.8 61.6 42.4 December 8,009 97.5 0.6 48.4 27.6 Total 67,791 97.6 0.5 334 25.2 Precipitation Loss 2 E January 0.0 0.0 0.0 : Cu distribution February 0.0 0.0 0.0 ＝0.05% March 0.0 0.1 0.0 April 0.0 0.0 0.0 May 0.0 0.0 0.0 June 0.0 0.1 0.0 July 0.0 0.1 0.0 August 0.0 0.1 0.0 September 0.0 0.1 0.0 October 0.0 0.1 0.0 November 0.0 0.1 0.0 December 0.0 0.1 0.0 Total 0.0 1 0.0 Precipitate Cu F January 90 2.0 77.8 70.0 79.5 95.0 : Cement copper February 75 1.6 82.4 61.9 77.7 95.0 March 97 2.0 78.8 76.7 76.5 95.0 April 73 1.9 81.3 59.6 83.9 95.0 May 77 1.7 81.2 62.8 77.8 95.0 June 115 1.8 72.8 84.0 76.6 95.0 July 110 2.2 78.6 86.6 82.0 95.0 August 125 2.0 78.0 97.2 77.9 95.0 September 106 1.6 71.3 75.8 60.9 95.0 October 76 1.1 77.3 58.6 47.9 95.0 November 101 1.3 77.0 77.9 53.6 95.0 December 156 1.9 76.0 118.6 67.7 95.0 Total 1,203 1.7 77.3 930 70.1 95.0 Waste water G January 0.0 3.6 4.1 February 0.0 3.2 4.0 March 0.0 4.0 4.0 April 0.0 3.1 4.4 May 0.0 3.3 4.0 June 0.0 4.4 4.0 July 0.0 4.5 4.3 August 0.0 5.1 4.1 September 0.0 3.9 3.2 October 0.0 3.0 2.5 November 0.0 4.0 2.8 December 0.0 6.2 3.5 Total 0.0 48 3.6 3-30 Table 3-10 Result of processing for oxide copper ore in 1999 at Ovalle plant, ENAMI *1: RCU Rate of capacity utilization(Cap.: 14,000t/month: 168,000t/year) Year Process Product Month Ore Tonnage Cu t distribut.% RCU*1 % grade % t distribut.% leach rate % preci.rate % 1999 Crushing, Run-of-mine ore A → January 10,508 100.0 75.1 2.0 212.8 100.0 Agglomeration B, C, D February 12,400 100.0 88.6 2.0 243.3 100.0 March 10,907 100.0 77.9 2.1 227.6 100.0 April 4,804 100.0 34.3 2.2 106.3 100.0 May 5,777 100.0 41.3 2.0 117.3 100.0 June 6,438 100.0 46.0 2.0 127.2 100.0 July 4,006 100.0 28.6 2.8 110.7 100.0 August 5,115 100.0 36.5 2.4 124.4 100.0 September 8,439 100.0 60.3 1.9 160.6 100.0 October 7,208 100.0 51.5 2.1 149.5 100.0 November 8,179 100.0 58.4 1.8 150.5 100.0 December 7,758 100.0 55.4 2.0 150.9 100.0 Total 91,539 100.0 54.5 2.1 1,881 100.0 Crushing, Loss 1 B January 105 1.0 1.6 1.6 0.8 Agglomeration, : Ore distribution February 124 1.0 2.2 2.7 1.1 Leaching ＝ 1.0% March 109 1.0 1.8 2.0 0.9 April 48 1.0 2.6 1.2 1.2 May 58 1.0 2.0 1.2 1.0 June 64 1.0 1.6 1.0 0.8 July 40 1.0 3.0 1.2 1.1 August 51 1.0 2.6 1.3 1.1 September 84 1.0 2.2 1.9 1.2 October 72 1.0 2.5 1.8 1.2 November 82 1.0 1.9 1.5 1.0 December 78 1.0 1.5 1.2 0.8 Total 915 1.0 2.0 19 1.0 Leaching Solution C → January 0.0 161.3 75.8 76.4 E, F, G February 0.0 192.6 79.2 80.1 March 0.0 174.5 76.6 77.3 April 0.0 79.3 74.6 75.5 May 0.0 88.3 75.3 76.1 June 0.0 106.9 84.0 84.7 July 0.0 90.6 81.8 82.7 August 0.0 101.8 81.8 82.7 September 0.0 130.9 81.5 82.4 October 0.0 122.0 81.6 82.6 November 0.0 122.0 81.0 81.9 December 0.0 122.8 81.3 82.0 Total 0.0 1,493 79.4 80.1 Waste ore D January 10,242 97.5 0.5 49.9 23.4 February 12,083 97.4 0.4 48.0 19.7 March 10,623 97.4 0.5 51.2 22.5 April 4,676 97.3 0.6 25.8 24.3 May 5,631 97.5 0.5 27.8 23.7 June 6,267 97.3 0.3 19.3 15.2 July 3,876 96.7 0.5 18.9 17.1 August 4,962 97.0 0.4 21.3 17.1 September 8,224 97.4 0.3 27.9 17.4 October 7,014 97.3 0.4 25.7 17.2 November 7,976 97.5 0.3 27.0 17.9 December 7,558 97.4 0.4 27.0 17.9 Total 89,131 97.4 0.4 370 19.7 Precipitation Loss 2 E January 0.0 0.1 0.0 : Cu distribution February 0.0 0.1 0.0 ＝0.05% March 0.0 0.1 0.0 April 0.0 0.1 0.0 May 0.0 0.1 0.0 June 0.0 0.1 0.0 July 0.0 0.1 0.0 August 0.0 0.1 0.0 September 0.0 0.1 0.0 October 0.0 0.1 0.0 November 0.0 0.1 0.0 December 0.0 0.1 0.0 Total 0.0 1 0.0 Precipitate Cu F January 188 1.8 81.7 153.2 72.0 95.0 : Cement copper February 235 1.9 77.9 182.9 75.2 94.9 March 194 1.8 85.3 165.6 72.8 94.9 April 95 2.0 78.9 75.3 70.8 94.9 May 115 2.0 72.8 83.8 71.5 94.9 June 125 1.9 81.0 101.5 79.8 94.9 July 103 2.6 83.7 86.0 77.7 94.9 August 124 2.4 78.1 96.6 77.7 94.9 September 144 1.7 86.5 124.2 77.4 94.9 October 141 2.0 82.3 115.8 77.4 94.9 November 139 1.7 83.5 115.8 76.9 94.9 December 143 1.8 81.5 116.6 77.2 94.9 Total 1,745 1.9 81.2 1,417 75.3 94.9 Waste water G January 0.0 8.0 3.7 February 0.0 9.6 4.0 March 0.0 8.7 3.8 April 0.0 4.0 3.7 May 0.0 4.4 3.8 June 0.0 5.3 4.2 July 0.0 4.5 4.1 August 0.0 5.1 4.1 September 0.0 6.5 4.1 October 0.0 6.1 4.1 November 0.0 6.1 4.0 December 0.0 6.1 4.1 Total 0.0 74 4.0 3-31 Table 3-11 Result of processing for oxide copper ore in 2000 at Ovalle plant, ENAMI *1: RCU Rate of capacity utilization(Cap.: 14,000t/month: 168,000t/year) Year Process Product Month Ore Tonnage Cu t distribut.% RCU*1 % grade % t distribut.% leach rate % preci.rate % 2000 Crushing, Run-of-mine ore A → January 3,258 100.0 23.3 2.1 69.3 100.0 Agglomeration B, C, D February 0 0.0 0.0 0.0 0.0 0.0 March 4,441 100.0 31.7 2.7 117.7 100.0 April 0 0.0 0.0 0.0 0.0 0.0 May 5,152 100.0 36.8 2.3 120.6 100.0 June 2,299 100.0 16.4 2.4 54.0 100.0 July 3,491 100.0 24.9 2.3 81.0 100.0 August 5,380 100.0 38.4 2.3 123.7 100.0 September 4,930 100.0 35.2 2.2 105.9 100.0 October 5,000 100.0 35.7 2.1 102.7 100.0 November 4,409 100.0 31.5 2.2 96.0 100.0 December 4,006 100.0 28.6 2.2 88.5 100.0 Total 42,365 100.0 25.2 2.3 959 100.0 Crushing, Loss 1 B January 33 1.0 1.9 0.6 0.9 Agglomeration, : Ore distribution February 0 0.0 0.0 0.0 0.0 Leaching ＝ 1.0% March 44 1.0 2.7 1.2 1.0 April 0 0.0 0.0 0.0 0.0 May 52 1.0 2.3 1.2 1.0 June 23 1.0 2.4 0.5 1.0 July 35 1.0 2.3 0.8 1.0 August 54 1.0 2.3 1.2 1.0 September 49 1.0 1.9 1.0 0.9 October 50 1.0 2.5 1.2 1.2 November 44 1.0 1.8 0.8 0.8 December 40 1.0 2.2 0.9 1.0 Total 424 1.0 2.2 9 1.0 Leaching Solution C → January 0.0 56.8 82.0 82.7 E, F, G February 0.0 0.0 0.0 0.0 March 0.0 96.3 81.8 82.6 April 0.0 0.0 0.0 0.0 May 0.0 98.6 81.8 82.6 June 0.0 44.2 81.8 82.6 July 0.0 66.3 81.8 82.6 August 0.0 101.2 81.8 82.6 September 0.0 82.4 77.8 78.5 October 0.0 84.0 81.8 82.8 November 0.0 78.6 82.0 82.6 December 0.0 72.4 81.8 82.6 Total 0.0 781 81.4 82.2 Waste ore D January 3,169 97.3 0.4 11.9 17.1 February 0 0.0 0.0 0.0 0.0 March 4,301 96.8 0.5 20.2 17.2 April 0 0.0 0.0 0.0 0.0 May 5,002 97.1 0.4 20.7 17.2 June 2,231 97.1 0.4 9.3 17.2 July 2,390 68.5 0.4 13.9 17.2 August 5,225 97.1 0.4 21.3 17.2 September 4,799 97.3 0.5 22.6 21.3 October 4,866 97.3 0.4 17.4 17.0 November 4,287 97.2 0.4 16.5 17.2 December 3,893 97.2 0.4 15.2 17.2 Total 40,161 94.8 0.4 169 17.6 Precipitation Loss 2 E January 0.0 0.0 0.0 : Cu distribution February 0.0 0.0 0.0 ＝0.05% March 0.0 0.1 0.0 April 0.0 0.0 0.0 May 0.0 0.1 0.0 June 0.0 0.0 0.0 July 0.0 0.0 0.0 August 0.0 0.1 0.0 September 0.0 0.1 0.0 October 0.0 0.1 0.0 November 0.0 0.0 0.1 December 0.0 0.0 0.0 Total 0.0 0 0.0 Precipitate Cu F January 65 2.0 83.4 54.0 77.9 95.0 : Cement copper February 0 0.0 0.0 0.0 0.0 0.0 March 113 2.5 80.8 91.4 77.7 94.9 April 0 0.0 0.0 0.0 0.0 0.0 May 113 2.2 82.5 93.6 77.7 94.9 June 50 2.2 84.0 42.0 77.7 94.9 July 78 2.2 80.4 62.9 77.7 94.9 August 113 2.1 84.8 96.1 77.7 94.9 September 95 1.9 82.4 78.2 73.9 94.9 October 97 1.9 82.6 79.8 77.7 94.9 November 91 2.1 82.3 74.7 77.8 94.9 December 79 2.0 87.3 68.8 77.7 94.9 Total 894 2.1 82.9 741 77.3 94.9 Waste water G January 0.0 2.8 4.1 February 0.0 0.0 0.0 March 0.0 4.8 4.1 April 0.0 0.0 0.0 May 0.0 4.9 4.1 June 0.0 2.2 4.1 July 0.0 3.3 4.1 August 0.0 5.1 4.1 September 0.0 4.1 3.9 October 0.0 4.2 4.1 November 0.0 3.9 4.1 December 0.0 3.6 4.1 Total 0.0 39 4.1 3-32 Table 3-13 Result of RCU for processing of oxide copper ore at Ovalle plant, ENAMI Note RCU: Rate of capacity utilization (Cap.: 14,000t/month: 168,000t/year) Cu Metal Price: LME Grade A Settlement (Original: ～93.6: £ /MT, 93.7～: $/MT) Ore Tonnage Cu Cu Metal Year Product Month t RCU % grade % t LME ¢ /lb 1994 Run-of-mine ore January 10,017 71.6 2.1 207.5 81.89 February 12,593 90.0 2.0 256.4 84.12 March 13,145 93.9 2.1 278.3 86.86 April 15,425 110.2 2.1 329.9 85.36 May 12,346 88.2 2.1 262.4 97.55 June 12,094 86.4 2.1 253.5 107.24 July 11,867 84.8 2.1 249.9 111.50 August 10,191 72.8 2.1 215.9 109.15 September 12,478 89.1 2.1 262.4 113.67 October 10,615 75.8 2.2 230.0 115.52 November 11,766 84.0 2.1 248.9 127.03 December 10,294 73.5 2.3 237.5 135.35 Total 142,831 85.0 2.1 3,033 104.60 1995 Run-of-mine ore January 9,764 69.7 2.3 225.5 136.48 February 9,592 68.5 2.2 208.0 130.53 March 11,165 79.7 2.2 249.6 132.63 April 10,598 75.7 2.2 228.4 131.70 May 10,823 77.3 2.2 237.1 125.80 June 10,420 74.4 2.2 230.2 135.84 July 10,928 78.1 2.2 240.2 139.51 August 10,686 76.3 2.2 239.7 137.75 September 9,925 70.9 2.3 223.1 132.25 October 10,278 73.4 2.3 234.7 127.62 November 10,579 75.6 2.3 240.4 135.05 December 11,598 82.8 2.2 256.8 132.73 Total 126,356 75.2 2.2 2,814 133.16 1996 Run-of-mine ore January 12,843 91.7 2.2 281.5 118.68 February 13,644 97.5 2.3 314.1 115.11 March 12,436 88.8 2.3 285.6 116.17 April 12,517 89.4 2.3 292.7 117.74 May 11,322 80.9 2.2 251.1 120.58 June 12,626 90.2 2.2 273.8 90.27 July 12,568 89.8 2.1 265.6 90.06 August 11,662 83.3 2.3 262.0 91.11 September 11,596 82.8 2.2 253.3 88.06 October 12,164 86.9 2.2 261.6 88.96 November 8,232 58.8 2.2 181.8 101.19 December 6,837 48.8 2.0 134.4 102.88 Total 138,449 82.4 2.2 3,058 104.09 1997 Run-of-mine ore January 6,808 48.6 1.9 128.6 110.45 February 4,584 32.7 2.1 96.5 109.13 March 8,512 60.8 1.9 160.2 109.83 April 9,888 70.6 1.4 141.6 108.46 May 5,251 37.5 2.1 110.6 114.05 June 2,170 15.5 2.5 53.2 118.51 July 3,585 25.6 2.2 78.8 111.15 August 4,819 34.4 2.3 109.4 102.11 September 3,220 23.0 2.2 72.1 95.59 October 3,669 26.2 2.1 78.5 93.09 November 4,170 29.8 2.2 90.3 86.97 December 4,793 34.2 2.1 100.1 79.94 Total 61,468 36.6 2.0 1,220 103.27

3-33 1998 Run-of-mine ore January 4,425 31.6 2.0 88.1 76.59 February 4,580 32.7 1.7 79.7 75.51 March 4,927 35.2 2.0 100.2 79.29 April 3,812 27.2 1.9 71.0 81.69 May 4,555 32.5 1.8 80.7 78.58 June 6,495 46.4 1.7 109.7 75.32 July 5,062 36.2 2.1 105.6 74.89 August 6,306 45.0 2.0 124.8 73.52 September 6,525 46.6 1.9 124.5 74.74 October 7,011 50.1 1.7 122.3 71.96 November 7,550 53.9 1.9 145.2 71.39 December 8,216 58.7 2.1 175.2 66.84 Total 69,465 41.3 1.9 1,327 75.05 1999 Run-of-mine ore January 10,508 75.1 2.0 212.8 64.92 February 12,400 88.6 2.0 243.3 63.99 March 10,907 77.9 2.1 227.6 62.52 April 4,804 34.3 2.2 106.3 66.50 May 5,777 41.3 2.0 117.3 68.55 June 6,438 46.0 2.0 127.2 64.52 July 4,006 28.6 2.8 110.7 74.39 August 5,115 36.5 2.4 124.4 74.74 September 8,439 60.3 1.9 160.6 79.39 October 7,208 51.5 2.1 149.5 78.21 November 8,179 58.4 1.8 150.5 78.36 December 7,758 55.4 2.0 150.9 80.05 Total 91,539 54.5 2.1 1,881 71.34 2000 Run-of-mine ore January 3,258 23.3 2.1 69.3 83.64 February 0 0.0 0.0 0.0 81.69 March 4,441 31.7 2.7 117.7 78.90 April 0 0.0 0.0 0.0 76.15 May 5,152 36.8 2.3 120.6 80.99 June 2,299 16.4 2.4 54.0 79.52 July 3,491 24.9 2.3 81.0 81.62 August 5,380 38.4 2.3 123.7 84.18 September 4,930 35.2 2.2 105.9 88.92 October 5,000 35.7 2.1 102.7 86.12 November 4,409 31.5 2.2 96.0 81.43 December 4,006 28.6 2.2 88.5 83.94 Total 42,365 25.2 2.3 959 82.26

3-34 Table 3-14 Copper Metal Price ¢ /lb Note LME: Grade A Settlement ¢ /lb [Original: ～93.6: £ /MT, 93.7～: $/MT]、COMEX: First Position ¢ /lb[～89.12: S.G.Price, 90.1～: H.G.Price] 1994 1995 1996 1997 1998 1999 2000 2001 2002 LME COMEX LME COMEX LME COMEX LME COMEX LME COMEX LME COMEX LME COMEX LME COMEX LME COMEX Jan. 81.89 83.84 136.48 139.91 118.68 118.09 110.45 108.29 76.59 76.88 64.92 65.12 83.64 84.84 81.08 83.70 68.22 69.79 Feb. 84.12 87.13 130.53 133.77 115.11 116.25 109.13 110.23 75.51 75.52 63.99 63.94 81.69 82.41 80.09 82.01 70.85 72.23 Mar. 86.86 89.76 132.63 139.04 116.17 118.20 109.83 114.80 79.29 79.69 62.52 62.50 78.90 79.63 78.87 80.07 72.80 74.53 Apr. 85.36 87.87 131.70 134.00 117.74 119.29 108.46 109.70 81.69 81.58 66.50 67.01 76.15 77.36 75.49 76.26 72.14 73.11 3-35 May 97.55 100.30 125.80 127.93 120.58 123.33 114.05 115.25 78.58 78.02 68.55 69.06 80.99 82.80 73.30 76.85 72.38 73.22 June 107.24 108.58 135.84 137.76 90.27 105.70 118.51 117.57 75.32 74.90 64.52 65.23 79.52 80.74 72.96 72.58 74.73 76.23 July 111.50 111.68 139.51 138.16 90.06 90.57 111.15 109.94 74.89 75.37 74.39 76.02 81.62 83.93 69.18 69.44 Aug. 109.15 109.38 137.75 137.77 91.11 92.14 102.11 102.11 73.52 73.30 74.74 75.88 84.18 86.67 66.43 67.34 Sep. 113.67 120.05 132.25 132.14 88.06 90.51 95.59 95.14 74.74 75.62 79.39 80.89 88.92 91.49 64.70 65.43 Oct. 115.52 118.90 127.62 128.00 88.96 93.53 93.09 93.08 71.96 72.25 78.21 79.30 86.12 87.63 62.47 63.20 Nov. 127.03 129.97 135.05 136.50 101.19 100.80 86.97 87.55 71.39 71.48 78.36 79.10 81.43 83.25 64.76 66.09 Dec. 135.35 136.86 132.73 131.78 102.88 102.78 79.94 79.29 66.84 66.21 80.05 81.35 83.94 86.92 66.76 67.83

Ave. 104.60 107.03 133.16 134.73 104.09 105.87 103.27 103.58 75.03 75.08 71.34 72.11 82.26 83.97 71.59 72.57 Table 3-16 Target of Processing for Oxide Copper Ore：Ovalle Plant, ENAMI

For the year Actual situat. In 2000 In 1994～2000 Measures Diff.：Ｘ1－Ｙ Diff.：Ｘ2－Ｙ Target：Ｘ1 Max.：Ｘ2 Result：Ｙ Results or expected outside circumference (◇) 1. Rate of capacity utilization: RCU % 90.0 57.1 25.2 25.2～85.0: Ave.57.2 +64.8 +31.9 1) Incentive for custom ore by ENAMI t/year 151,200 96,000 42,365 42,365～142,831: Ave.96,096 +108835 +53,635 2) Management of mine by ENAMI (1) Ore tonnage (grade of Cu) (Cu-%) (same as right)(same as right) (2.3) (1.9～2.3: Ave.2.1) (±0) (±0) 3) Decrease of cut-off grade of custom ore 4) Steady secondary leaching for primary leaching waste (2) Capacity t/year 168,000168,000 168,000168,000 ±0 ±0 5) Copper metal price >80～90¢ /lb(◇)

2. Total Cu recovery rate % 81.5 (same as left) 77.3 56.8～77.3: Ave.72.1 +4.2 +4.2 （Formula）Total Cu recovery rate ＝{100－(Cu loss 1)}×(Cu leaching rate)/100 ×(Cu precipitation rate)/100 －Cu loss 2 (1) Cu loss 1 distrib.: crush., agglom., leach. % 0.5 (same as left) 1.0 0.9～1.1: Ave.1.0 -0.5 -0.5 1) Prevention of dust, 2) Wet treatment for fines (2) Cu leaching rate: (Cu distrib. recovered by % 86.3 (same as left) 82.2 60.3～82.2: Ave.76.7 +4.1 +4.1 1) Optimizing particle size, etc.

3-36 return of waste/treated solution to leaching (3.1) (same as left) (0.0) (0.0) (+3.1) (+3.1) 2) Return of waste/treated solution to leaching section % section) [Ref.: Cu distrib. in waste solution] [1.0] (same as left) [4.1] [2.9～4.1: Ave.3.8] [-3.1] [-3.1] : utilization of bacteria, Fe3+, etc. (3) Cu precipitation rate % 95.0 (same as left) 94.9 94.9～95.0: Ave.94.9 +0.1 +0.1 1) More management for stabilization (4) Cu loss 2 distrib.：precipitation % 0.05 (same as left) 0.05 0.05 ±0 ±0 1) ditto

3. Product: copper precipitate (cement copper) (1) Quantity of copper precipitate 1) Quant. t/year Cal. 3,415 Cal. 2,168 894 894～2,907: Ave.1,865 +2,521 +1,274 and grade of Cu of the one 2) Grade % 83.0 (same as left) 82.9 75.3～82.9: Ave.78.3 +0.1 +0.1 1) More management for stabilization (2) Quantity of Cu 1) Quant. t/year Cal. 2,834 Cal.1,799 741 741～2,261: Ave.1,448 +2,093 +1,058

4. Income [Ａ]：estimation US$/year 2,611,519 1,657,461 654,485 +1,957,034 +1,002,976

5. Production cost [Ｂ] US$/year 3,347,568 2,125,440 987,528 +2,360,040 +1,137,912 US$/crude ore t 22.14 (same as left) 23.31 -1.17 -1.17 (1) Production unit cost 1) Reduction of cost of 5% for every item (¢ /prod.Cu-lb) (Cal. 53.6) (Cal. 53.6) (Cal. 60.5) (-4.8) (-4.8)

6. Production gross profit [Ａ－Ｂ] US$/year -735,949 -467,979 -333,043 -402,906 -134,936 ＜Improved money for operation＞ US$/year <+452,676> <+286,704> 3.2.3 Sulfide Cu Ore Processing (1) Processing method From sulfide Cu ores, Cu concentrate is produced through crushing, grinding and flotation steps. Outline of flow diagram and material balance sheet (actual results in 2000) are shown in Figure 3-5 and the flow diagram with plant facilities are in Figure 3-6 as well. (2) Metallurgical results After 1998, when Cu price is below 80¢ /lb, production has stayed at lower level due to difficulty of crude ore supply. Actual results of sulfide Cu ore processing after 1994 are shown in Table 3-17～24, unit operation cost (in 2000) is at the bottom of Table 3-3 of section 3.1 and unit consumption of major materials (in 2000) are in Table 3-25 respectively.

Table 3-25 Unit Consumption of Major Materials (in 2000) Grinding Flotation

Ball Slaked lime Flotation reagents Unit consumption 0.63 kg/crude ore t 2.21 kg/crude ore t 0.20 kg/crude ore t (3) Discussion on profit increase Total income of plant operation is expressed as a functional formula as below.

Income =∑[{Cap.×Ａ/100×Ｂ/100×(100-Ｃ)/100×Ｄ/100}(100-Ｅ)/100×Ｆ] : Sum of each lot

Here, Cap. : Installed capacity (t/month or t/year) A : Rate of capacity utilization (%) B : Cu grade (%) in crude ore C : Rate of handling losses (%) D : Cu recovery rate (%) E : Rate of waste time (%) F : Income received from ENAMI management 1) Cap. : Installed capacity ① Problem 1 : Increase in throughput greatly contributes to unit cost down. ② Study 1 : Possibility of mass production, increase in throughput ③ Results 1 : Since 1998, Cu price is too low (below 80¢ /lb) to increase ore throughput at Ovalle, but after 2001 the situation turned favorable to allow the increase with some crude ore storage. ④ Measure 1 : To encourage the surrounding miners through incentive payment for the crude ore supply. ENAMI’s own mining operation would be make that easier. ⑤ Target 1 : Increase in crude ore supply with increased plant capacity. Ovalle plant

3-37 capacity was increased in summer, 2002, from 7,000 to 11,000 ton/month by installation of mill, flotation machine, filter etc. 2) A : Rate of capacity utilization (hereinafter : RCU) ① Problem 2 : First priority is to keep RCU at higher level constantly. ② Study 2 : Reliable ore supply is indispensable to keep higher level of RCU. ③ Results 2 : RCU has been staying at low level as above mentioned, not as low as oxide Cu ores, though. This was caused by that ore suppliers are out of ENAMI’s control and also small or medium sized miners. Especially after 1998, when Cu price has stayed as low as 63～89¢ /lb, RCU at Ovalle was around 54%. Relation between actual RCU (1994～2000) and Cu price is shown in the following Tables and Figures.

Table 3-27 The Relation between RCU at Ovalle vs. Cu Price Cu metal price(*8)¢ /lb RCU (Rate of capacity utilization)(*9) % Period Price Range Ave. < 50 50～80 80～100 100 < Ave. 94.01～ Total 82～ 1 months 15 months 22 months 9 months 82.5 High 111.9 97.11 47 months 140 [2 %] [32 %] [47 %] [19 %] [100 %] 97.12～ Total 63～ 17 months 20 months 4 months 1 month 53.8 Low 76.5 01.05 42 months 89 [40 %] [48 %] [10 %] [2 %] [100 %] Note *8: LME Grade A Settlement *9: Percentages in [ ] are shown to be proportion of number of months during the period. As can be seen from these data, RCU and Cu price are strongly correlated. During the period of higher Cu price (over 82¢ /lb, averaged 112¢ /lb), RCU more than 80% was counted 66% of all cases (of total number of months), averaging 82.5%. Throughout that period, RCU recorded over 50%, which is better than oxide Cu ores. On the other hand, during the period of lower Cu price (below 89¢ /lb, averaged 76.5¢ /lb), RCU more than 80% was counted only 12%. RCU under 50% was as high as 40%, averaging 53.8%. Throughout the year 2000, RCU recorded 56.4%, unsatisfactorily. When Cu price is over 80 ～ 90 ¢ /lb, crude ores can be supplied comparatively easily, while hardly obtained if the price falls below this range. Sulfide Cu ores are generally less difficult to purchase than oxide Cu, though. In the year 2001, supply of sulfide ores is better than the previous year and RCU is now increasing favorably. ④ Measure 2 : Increase in RCU should be aimed for reduction of unit cost and for increase in operation profit. Further, discussions should be made on price incentive at ore purchasing, extension of loans for exploration works, technical instruction to decrease mining costs on supplier side (integration of mining and transportation etc.) and also modification of the Articles of Association to allow ENAMI

3-38 itself to perform mining operation. Currently, price incentive is being given for increase of ore supply. ⑤ Target 2 : Increase of RCU up to 90% (=7,000t/month [84,000t/year]×90% =6,300t/month [75,600t/year]) from 56.4% in 2000 (42.3 ～ 95.5%, averaged 69.2%). For this purpose, stable price over 80～90¢ /lb and price incentive are necessary. 3) B (Cu [Au,Ag] grade in crude ore) ① Problem 3 : If unit operation cost can be reduced at Ovalle, it is possible to lower cut-off grade for the supplying mines and to increase monthly output constantly. This also encourages small mines to increase their reserves and to allow more flexible mining operation. ② Study 3 : By reducing unit cost, Cu cut-off grade may be lowered. ③ Results 3 : Recent Cu grade ranges 1.7 ～ 2.9% (1994 ～ 2000, averaged 2.2%). Currently, reduction in cost as well as cut-off grade are being proceeded to stabilize ore supply. ④ Measure 3 : Further decrease in cut-off point is needed. In case of sulfide ores, only sulfide minerals contribute to Cu recovery rate. So attention should be paid to keep oxide ores from mixing into crude ores. By- product metals like Au and Ag, as well as penalizing elements at point of sales should be carefully controlled. ⑤ Target 3 : To decrease Cu cut-off grade down to 1% by unit cost reduction Monthly lowest grade reported in 2000 was 1.5% (1.3～4.5%, 1994～ 2000) 4) C (Rate of handling losses) At present, no losses are regularly counted. 4)-1 Dust losses ① Problem 4 : At storage and transportation of crushed ores, dusts containing higher content of Cu, may be rising. This results in Cu loss in recovery rate. If this losses are decreased, Cu recovery rate will be up. ② Study 4 : To decrease dust rising ③ Results 4 : Currently, dust rises much less than before because of water showering effect. ④ Measure 4 : Further reduction by decreasing ore movement. In future, separation of fine particles(*10) as well as wet treatment are to be studied. In the latter case, assessment of crude ores by lot sampling should be discussed separately. *10 : primary slime at ore reception and secondary from the crushing step ⑤ Target 4 : Continuous decrease in dust rising 4)-2 Pulp losses (leak, spill etc.) in grinding, flotation and filtering sections ① Problem 5 : Increase of Cu recovery by decreasing pulp losses

3-39 ② Study 5 : Prevention of pulp leak, spill etc. ③ Results 5 : These losses are now little owing to installed pits for reservoir of leaked pulp. ④ Measure 5 : Continuation of present situation. ⑤ Target 5 : Prevention of losses. 4)-3 Losses from Cu concentrate ① Problem 6 : To keep Cu recovery up by decreasing losses at filtering, drying, loading sites etc. ② Study 6 : Prevention of Cu losses by dust rising ③ Results 6 : Losses are little owing to windshield by the yard. ④ Measure 6 : Continuation of present situation. Prevention of losses at loading and transportation sites by laying sheets or covers. ⑤ Target 6 : Prevention of losses 5) D Cu (Au, Ag) recovery rate 5)-1 Component minerals

① Cu minerals Primary Cu minerals Chalcopyrite CuFeS2

Bornite Cu5FeS4 Secondary Cu minerals Covellite CuS

Chalcocite Cu2S ② Gangue minerals Limonite Goethite

Pyrite Fe2S

Hematite Fe2O3 Galena PbS

Quartz SiO2 and others 5)-2 Necessary basic studies ① Studies on minerals The following studies are needed on crude ore, concentrate and flotation tailing. a) Component minerals and their ratio b) Form analysis of sulfide Cu minerals (idiomorphic or allotriomorphic) Content of middling particles in concentrate and tailing c) Liberation size of target minerals ② Studies on processing First, analysis of basic factors shall be carried out through the “Design of experiment” Method. a) Factor 1 : minerals to be recovered b) Factor 2 : size distribution of grinding product (flotation feed), → degree of liberation c) Factor 3 : flotation conditions → conditioning method (shape of conditioning tank(s), agitation (number and rotating direction of impeller, with or without pumps), type of flotation reagents(*11), addition method, order, number of stage,

3-40 point of addition, pulp temperature etc. *11 : pH regulator, activator, depressant, sulphurizer, dispersant, collector, frother etc. d) Factor 4 : flotation time → pulp density, volume of flotation cell e) Factor 5 : flotation process → single, straight differential, bulk differential etc. f) Factor 6 : flotation machine → box type (mechanical agitation), column, pneumatic and others. g) Factor 7 : control system → automatic, manual, process control (feed back, feed- forward, fuzzy, expert system etc.) h) Factor 8 : frequency of stop → especially in grinding and flotation i) Factor 9 : removal of slime, separate treatment → with or without j) Factor 10 : degree of surface oxidation of sulfide minerals → exposure time after grinding to atmosphere. Next, improvement of recovery shall be studied. a) Target of flotation recovery → required flotation time : amount of Cu to be floated, “recovery vs. flotation time” b) Measures against shortage of flotation time ・inappropriate : increase of flotation cells → more machines needed per unit area, cost will be up ・appropriate 1 : higher pulp density, decrease of flushing water in float troughs → fewer machines per unit area, cost down ・appropriate 2 : increase in liberation degree by effective grinding system, decrease in required flotation time → fewer machines per unit area, cost down Further, increase in concentrate grade shall be studied. a) Target of concentrate grade → required number of cleaning stage : cleaning stage vs. concentrate grade curve b) Measures when cleaning stage is insufficient ・Introduction of column type machine → it is possible to make froth layer thick, five to ten times as thick as box type and to stabilize operation ・Thickening or filtering of rougher concentrate → removal of excess reagents ・Others → quantitative and qualitative optimization of reagents etc. 5)-3 Cu recovery rate ① Problem 7 : Cu recovery under the most suitable grinding and flotation conditions ② Study 7 : The most suitable grinding and flotation conditions ③ Results 7 : To be improved further. Current size distribution of grinding product (flotation feed) : 76～80%, -200mesh ④ Measure 7 a) Studies on minerals : Identification of component minerals, form analysis of Cu sulfide minerals, degree of liberation etc. b) Studies on processing 1 : Necessary and sufficient liberation

3-41 (Ordinarily) All particles are ground for complete liberation of target minerals, however, secondary slimes produced may influence resulting in lower recovery and higher cost.

(Measure) Grinding time is reduced to produce coarser product and only insufficient particles are ground again avoiding excessive cost. Thus, effective grinding performance and cost saving are achieved. ・ Regrinding 1 : As froth product from rougher section is well liberated and easily floatable, it is sent directly to cleaning section. On the other hand, scavenger froth is not well liberated and less floatable. It is now returned to rougher section but is better to be ground again as shown in Figure 3-8. ・ Regrinding 2 : Sink product from the cleaning section is to be ground in a small mill. c) Studies on processing 2 : Optimization of grinding process ・ Ball mill : one stage ・ Ball mill : two stages, series or parallel ・ Rod mill- ball mill : two stages, series ・ Semi autogenous mill- ball mill : two stages, series ・ Others d) Studies on processing 3 : Analysis of various flotation factors e) Studies on processing 4 : Increase in flotation recovery (program) flotation curve → required recovery → necessary flotation time [ordinary] Increase in flotation cell volume : higher cost and more space

[measure] The most effective measure is increase in flotation time. This is effectively achieved by increase of pulp density. Slope of froth trough should be increased to reduce flushing water. This increases pulp density and also flotation time. If necessary, a pump is installed. In grinding section, water should be reduced. At present, pulp density (PD) at flotation is around 20% (feed : 26.11, tailing : 14.88%). If this is increased, flotation time is up as below. When PD is up to 25% (+5%) : flotation time is up by 30% 30% (+10%) : 65% 35% (+15%) 95% f) Studies on processing 5 : Improvement of (Cu) concentrate grade (program) cleaning curve → required grade → necessary cleaning stages ⑤ Target 7 : Improvement of Cu recovery up to 91% constantly from 84.3% in 2000 ( 84.3～93.5%, averaged 89.9%, 1994～2000).

3-42 5)-4 Recovery rate of Au, Ag and others ① Problem 8 : Higher recovery rate ② Study 8 : Most suitable flotation conditions ③ Results 8 : Only Au and Ag are counted. Molybdenum is not found. Au and Ag are controlled together with Cu involuntarily. ④ Measure 8 : Continuation of current operation. Mineralogical studies are needed. ⑤ Target 8 : Recovery of Au and Ag are to be increased along with Cu. 5)-5 Cu concentrate grade ① Problem 9 : Most suitable Cu grade balancing with recovery rate ② Study 9 : Suitable grinding and flotation ③ Results 9 : Recovery rate is now more focused than concentrate grade. Concentrate grade is variable depending upon proportion of primary/secondary Cu minerals. However, concentrate grade should be improved because major Cu mineral is chalcopyrite, of which Cu content is 34.6%. ④ Measure 9 : Review of cleaning flow. At present, froth product of the first rougher cell is directly sent to the final concentrate. But this should be cleaned through further step for grade up because middling or mixed particles are often contained. ・ Employment of column type machine is to be studied. ・ Re-grinding step is to be studied. ⑤ Target 9 : Concentrate grade up to 30%, average of large scale Cu mines, from 22.3% in 2000 (22.0～29.1%, 1994～2000). 5)-6 Impurity elements in Cu concentrate ① Problem 10 : Prevention of harmful elements to smelting operation (Pb, Zn, As, Sb, Bi, Ni, F, Cl etc.). ② Study 10 : Chemical analysis of crude ores, stop ore purchase if necessary. ③ Results 10 : Currently no special attention is paid. ④ Measure 10 : Discussion to be made, if necessary. ⑤ Target 10 : These elements shall be controlled in future. 6) E (Rate of waste time) ① Problem 11 : Decrease of waste time ② Study 11 : Prevention of waste time due to ore shortage ・ Prevention of mechanical troubles ・ Prevention of human accidents ・ Prevention of labor disputes ③ Results 11 : Ore shortage is now a big problem resulting in serious decrease of operation rate. This has been caused either by lower Cu price or long term vacation for suppliers or both. Refer to 2). Other items have been well controlled.

3-43 ④ Measure 11 : Further decrease in waste time ⑤ Target 11 : Increase in operation rate through prevention of ore shortage. Refer to 2). 7) F (Income received from ENAMI management) ① Problem 12 : Increase in profit (income – expenditure) Income from sulfide ore processing is expressed as below. Net income at Ovalle plant = Commissions for (ore procurement + crushing + grinding, flotation) + valuation of Cu concentrate Thus, income at the plant is composed of various commissions and evaluation value of Cu concentrate, which is the difference between actual evaluation and the predetermined standards of the concentrate. ② Study 12 : Increase in ore throughput ・ Increase in Cu recovery and concentrate grade ③ Results 12 : Income from sulfide Cu ore processing is estimated as follows. ・ Actual performance in 2000 Total amount of actual treatment = Installed capacity (84,000ton/year) ×cap. use 56.4 % = 47,418ton/year Total income Y = US$ 493,362 /year ・ Annual target (estimated) Total amount to be treated annually = Installed capacity ×90% = 75,600ton/year Total income should be X = US$ 1,015,368～951,003/year ④ Measure 12 : Further increase in ore throughput, Cu recovery and concentrate grade. ⑤ Target 12 : Studies to be continued. Scale of operation (present and future) is also to be discussed. (4) Discussion on cost saving Total costs should be decreased finally, however at this moment, reduction in unit cost (US$/ton of crude ore or ¢ /lb-cu) is important as an operation index. As a whole, reduction by 5% should be achieved. That is, down to US$ 15.93/ton from US$ 16.77/ton in 2000 (from MEMORIA ANNUAL 2000, ENAMI). 1) Manpower saving ① Problem 13 : Optimization of organization as well as personnel ② Study 13 : Review along current and future operation ③ Results 13 : Reduction is now underway along the present situation ④ Measure 13 : Further review ⑤ Target 13 : Discussion to be continued 2) Energy saving ① Problem 14 : Optimization of operation efficiency : Reduction in energy like electric power, fuels etc. ② Study 14 : Full utilization of installed capacity as well as process review

3-44 ③ Results 14 : Full utilization of hourly capacity is now underway to achieve energy reduction. ④ Measure 14 : Intense operation (full use of hourly capacity) shall be continued for further energy reduction. ⑤ Target 14 : Discussion to be continued. 3) Material saving ① Problem 15 : Optimization of operation efficiency : Minimum consumption of liners and others. ② Study 15 : Full utilization of installed capacity as well as operation review. Study on anti-abrasive materials. ③ Results 15 : Full utilization of hourly capacity is now carried out for material saving. ④ Measure 15 : Employment of anti-abrasive liners in crushing step. This contributes to maintenance time and material saving. ⑤ Target 15 : Continuous study (5) Summary Improvements of present operation are summarized in Table 3-28 as a target of the sulfide ore processing. ・Improvement 1 : Increase of income ① Increase in capacity utilization rate : Up to 90% as an annual target [X] from actual result 56.4% [Y] in 2000. (Measure) Further increase of incentives for ore suppliers. Mine management by ENAMI itself. Decrease in cut-off grade of crude ores. Expectation of Cu price hike over 80～90¢ /lb etc. ② Increase of total Cu recovery : Up to 91.0% [X] as an annual target from 84.3%[Y] in 2000. (Measure) Most suitable grinding circuit. Increase in flotation pulp density. ③ Increase of Cu concentrate grade : Up to 30.0% [X] as an annual target from 22.3%[Y] in 2000. (Measure) Improvement of cleaning circuit. Employment of re-grinding. Study on column type machine in cleaning circuit. ・Improvement 2 : Cost saving Cost down from US$ 16.77/ton [Y] of crude ore in 2000 to US$ 15.93/ton [X] as an annual target. (Measure) Cost down by 5% on all items. Based upon the improvement above described, annual gain in the gross profit is estimated as the difference between the annual target (Total throughput = installed capacity 84,000ton/year× utilization rate 90% = 75,600ton/year) and the actual result (47,418ton/year) in 2000, the recent year. As the results, even if the rate of capacity utilization (operation rate) is increased up to 90% and also the above considerable improvements are realized, the operation inevitably stays in the

3-45 red. Thus, in the case of the annual target [X], US$ 188,940～253,305 of deficit is expected annually. This estimate is summarized in the following Table. Inside the parenthesis show the results without any improvement of operation. In other words, (in the Table below) of annual profit increase is expected with the improvement of the operation.

Summary of the Discussion on Gross Profit for Sulphide Cu Processing (US$/year) Year 2000 Difference Annual Target [X] [Y] [X-Y] Processing ore 75,600 47,418 +28,182 (t/year) Sales amount 1,015,368～951,003 493,362 +522,006～+457,641 [A] (798,546～736,585)

Production cost 1,204,308 795,200 +409,108 [B] (1,267,812) -188,940～-253,305 -301,838 +112,898～+48,533 Profit [A－B] (-469,266～-531,227) improvement>

3-46

Run-of-mine ore: Sulfide copper ore 47,418 dry t (Ore distribution 100.0%) Crushing *1, *2 1.71 Cu-%：811 Cu-t (Cu dis. 100.0%) 0.31 Au-g/t：14.9 Au-kg (Au dis. 100.0%) Grinding *2 3.5 Ag-g/t：167 Ag-kg (Ag dis. 100.0%)

Flotation *2

Flotation conc. Flotation tailing

Thickening *2 Tailing 44,350 dry t (Ore distribution 93.5%) 0.29 Cu-%：127 Cu-t (Cu dis. 15.7%) Over flow(-) Under flow(+) 0.19 Au-g/t：8.6 Au-kg (Au dis. 57.9%) (Clarified water) -2.3 Ag-g/t：-104 Ag-kg (Ag dis. –62.1%) *3 Filtering *2 Recycle water 1 Classifying 〈Tailing pond〉

Filtrate(-) Cake(+) Under flow(+) Over flow(-) Coarse size Recycle water 2 Banking Putting into pond

Particles(+) Clarified water(-)

Sedimentation Recycle water 3 Copper concentrate 3,068 dry t (Ore distribution 6.5%) 22.3 Cu-%：684 Cu-t (Cu dis. 84.3%)：Cu recovery 84.3% 2.05 Au-g/t：6.3 Au-kg (Au dis. 42.1%)：Au recovery 42.1% 88.3 Ag-g/t：271 Ag-kg (Ag dis. 162.1%)：Ag recovery 162.1% *3

Figure 3-5 Block Diagram(outline) with Material Balance for Sulfide Copper Ore in 2000 Ovalle Plant, ENAMI Note *1：Every lot for reception ore should be weighed, sampled and analyzed at reception and crushing sections to decide condition to buy ore. *2：Loss of all sections should be none. *3：Not clear.

3-47 Run-of-mine ore: Sulfide copper ore

1.Weighing

2.Crude ore stockyard

3.Coarse ore bin

4.Classifying

Coarse(+) Fine(-)

5.Primary crushing

6.Classifying

Coarse(+) Fine(-)

（ 7.Secondary crushing ）

（ 8.Classifying ）

Coarse(+) Fine(-)

9.Tertiary crushing

10.Sampling

11.Fine ore bin

12.Grinding

13.Classifying

Coarse(+) Fine(-)

14.Conditioning

15.Roughing 1

Froth Sink

19.Roughing 2

Ａ Froth Sink Ｂ 16.Solid/liquid sepa. 22.Scavenging 1

Over-flow(-) Under-flow(+) Froth Sink

17.Solid/liquid sepa. 20.Cleaning 1 23～27.Scavenging 2～6 : Filtering Filtrate Cake Froth Sink Froth Sink ＡＢ 18.Drying 21.Cleaning 2 Tailing

Recycle water Copper concentrate Froth Sink 28.Tailing pond Note Clarified water is to be recycled. .

Figure 3-6 Block Diagram for Sulfide Copper Ore: Ovalle Plant, ENAMI

3-48 （Figure 3-6）Equipment for Sulfide Ore: Ovalle Plant, ENAMI No. Process Equipment and specification Remarks 1 Weighing Truck Scale Every lot of crude ore Crude ore particle size 2 Crude ore stockyard ：-7” 3 Coarse ore bin Every lot of crude ore 4 Classifying Fixed Screen, Grizzly(opening 2･1/2”), 1unit Gyratory Crusher：Trylor, TY-1398F type, 3’φ, 5 Primary crushing 50t/h, 1 unit (spare circuit：Single Toggle Crusher, 1 unit) 6 Classifying Vibrating Screen(opening 3/4”), 1 unit 7 Secondary crushing Cone Crusher：Symons, SH type, 3’φ, 50t/h, 1 unit Abbreviated 8 Classifying Vibrating Screen(opening 1/4”), 1 unit according to case 9 Tertiary crushing Cone Crusher：Symons, SH type, 3’φ, 50t/h, 1 unit 10 Sampling Automatic sampling → analysis Every lot of crude ore 11 Fine ore bin Ball Mill：Head Wrightson, 7’×7’, 160t/d, 1 unit＋ Grinding feed particle 12 Grinding Traylor, 7’×6’, 140t/d, 1 unit size：-1/4”(-6.35mm) Hydro-cyclone：Vulco D-10B, 1 unit /ball mill(spare 13 Classifying 1 unit /ball mill) 14 Conditioning Flotation Conditioner, 1unit Flotation feed particle size ： -200mesh Flotation Machine：Krupp, NR159(≒Denver 21), 15 Roughing 1 (-0.074 mm) 76 ～ 1.5m3 /cell, 2cells, Free flow type：1R 80% Thickener：Dor Oliver, Drive Head type A, 140m3, 16 Solid/liquid separation 5’φ, 1 unit Solid/liquid separation Vacuum Filter：Dor Oliver, American Disk type 17 : Filtering 39216 –2R, 75’, 3disks 18 Drying Sunlight drying Flotation Machine ： Krupp, NR159, 1.5m3/cell, 19 Roughing 2 2cells, Free flow type：2R Flotation Machine：Denver, 18SP, 0.6 m3/cell, 2cells, 20 Cleaning 1 Cell to cell type：1C Flotation Machine：Denver, 18SP, 0.6 m3/cell, 2cells, 21 Cleaning 2 Cell to cell type：2C Flotation Machine ： Krupp, NR159, 1.5m3/cell, 22 Scavenging 1 4cells, Free flow type：1S Flotation Machine：Krupp, NR159, 1.5m3/cell, (4+4) cells, Free flow type：2,3S＋Denver, 24SD, 1.4 23～ Scavenging 2～6 m3/cell, (3+3)cells, Cell to cell type：4,5S＋ 27 Forrester, Supper charge(Air charge), Free flow type, 7mL, 約 10m3, 1cell：6S Hydro-cyclone, 1 unit：putting Over-flow(-) into 28 Tailing pond pond, and using Under -flow (+) for bank

3-49

/lb) ( price metal Cu ¢

160 140 120 100 80 60 40 20 0

/lb) -

¢ J

u J

Cu metal price(

RCU(%) - l Time

Cu metal price:LME Grade A Settlement 6

J RCU:Rate of capacity utilization

for Sulfide Copper Ore and Cu Metal Price n

RCU -

0 - n

80 60 40 20 a Figure 3-7 Relation between RCU(Rate of Capacity Utilization)

160 140 120 100 J

copper ore copper RCU ( %) for sulfide for %) ( RCU

3-50

Crushing product 〈In general〉

Grinding with closed circuit All ore particles are to be liberated.

Rougher [Flotation]

froth sink

Cleaning Scavenger

Concentrate froth sink

Tailing

Crushing product 〈Measures〉

Grinding with closed circuit A little coarser: partially, not liberated.

Rougher [Flotation]

froth sink

Cleaner * Scavenger

Concentrate froth sink

(much middling) Tailing

*: Small type regrinding mill is installed in this section.

Figure 3-8 Optimum Efficiency and Reduction of Cost in Grinding Section to Obtain Necessary and Sufficient Liberation Particle Size

3-51 Table 3-17 Result of Processing for Sulfide Copper Ore in 1994 at Ovalle plant, ENAMI *1: RCU Rate of capacity utilization(Cap.: 7,000t/month: 84,000t/year) Ore Tonnage Cu Au Ag Year Product Month t distribut. % RCU*1 % grade % t distribut. % grade g/t kg distribut. % grade g/t kg distribut. % 1994 Run-of-mine ore January 5,191 100.0 74.2 3.1 158.1 100.0 2.2 11.3 100.0 11.6 60.0 100.0 February 6,092 100.0 87.0 2.9 176.1 100.0 0.3 2.1 100.0 12.2 74.4 100.0 March 6,503 100.0 92.9 2.4 153.2 100.0 1.3 8.3 100.0 10.9 71.1 100.0 April 6,414 100.0 91.6 3.3 209.9 100.0 1.2 7.6 100.0 17.1 109.4 100.0 May 6,796 100.0 97.1 2.2 152.0 100.0 1.0 6.6 100.0 11.8 80.0 100.0 June 6,192 100.0 88.5 2.0 122.6 100.0 1.3 8.2 100.0 12.0 74.3 100.0 July 7,070 100.0 101.0 2.3 159.5 100.0 1.3 9.2 100.0 13.4 95.0 100.0 August 6,830 100.0 97.6 2.2 150.7 100.0 1.3 9.1 100.0 11.5 78.5 100.0 September 7,555 100.0 107.9 2.0 148.2 100.0 1.2 9.3 100.0 10.4 78.3 100.0 October 7,883 100.0 112.6 2.1 168.3 100.0 1.1 8.8 100.0 15.2 120.2 100.0 November 7,368 100.0 105.3 2.0 149.3 100.0 1.0 7.5 100.0 12.6 92.9 100.0 December 6,302 100.0 90.0 1.5 93.8 100.0 1.8 11.2 100.0 7.3 45.7 100.0 Total 80,196 100.0 95.5 2.3 1,842 100.0 1.2 99.0 100.0 12.2 979.9 100.0 Cu concentrate January 475 9.2 29.3 139.2 88.0 20.3 9.6 85.4 115.9 55.1 91.7 February 548 9.0 29.3 160.6 91.2 2.9 1.6 75.9 120.4 66.0 88.7 March 536 8.2 25.6 137.1 89.5 13.3 7.1 86.6 117.0 62.7 88.3 April 626 9.8 30.7 192.5 91.7 10.3 6.5 84.7 156.0 97.7 89.3 3-52 May 551 8.1 25.3 139.0 91.5 10.4 5.7 86.3 119.5 65.8 82.3 June 396 6.4 27.7 109.7 89.5 17.2 6.8 83.4 158.9 62.9 84.6 July 367 5.2 38.8 142.3 89.2 21.1 7.8 84.7 227.7 83.5 87.9 August 513 7.5 26.5 136.0 90.2 15.7 8.1 88.7 138.8 71.3 90.8 September 422 5.6 31.5 132.8 89.6 15.5 6.6 70.6 164.6 69.4 88.7 October 434 5.5 34.7 150.4 89.4 15.8 6.8 77.9 231.1 100.2 83.4 November 470 6.4 28.4 133.5 89.4 12.7 6.0 80.2 167.3 78.7 84.7 December 360 5.7 23.7 85.2 90.7 26.1 9.4 83.6 111.2 40.0 87.5 Total 5,698 7.1 29.1 1,658 90.0 14.4 81.9 82.7 149.8 853.4 87.1 Tailing January 4,716 90.8 0.4 18.9 12.0 0.4 1.7 14.6 1.1 5.0 8.3 February 5,544 91.0 0.3 15.5 8.8 0.1 0.5 24.1 1.5 8.4 11.3 March 5,967 91.8 0.3 16.1 10.5 0.2 1.1 13.4 1.4 8.3 11.7 April 5,787 90.2 0.3 17.4 8.3 0.2 1.2 15.3 2.0 11.7 10.7 May 6,245 91.9 0.2 12.9 8.5 0.2 0.9 13.7 2.3 14.2 17.7 June 5,796 93.6 0.2 12.9 10.5 0.2 1.4 16.6 2.0 11.4 15.4 July 6,703 94.8 0.3 17.2 10.8 0.2 1.4 15.3 1.7 11.5 12.1 August 6,316 92.5 0.2 14.8 9.8 0.2 1.0 11.3 1.1 7.2 9.2 September 7,133 94.4 0.2 15.4 10.4 0.4 2.7 29.4 1.2 8.9 11.3 October 7,450 94.5 0.2 17.9 10.6 0.3 1.9 22.1 2.7 20.0 16.6 November 6,897 93.6 0.2 15.8 10.6 0.2 1.5 19.8 2.1 14.2 15.3 December 5,942 94.3 0.2 8.7 9.3 0.3 1.8 16.4 1.0 5.7 12.5 Total 74,498 92.9 0.2 184 10.0 0.2 17.1 17.3 1.7 126.6 12.9 Table 3-18 Result of Processing for Sulfide Copper Ore in 1995 at Ovalle plant, ENAMI *1: RCU Rate of capacity utilization(Cap.: 7,000t/month: 84,000t/year) Ore Tonnage Cu Au Ag Year Product Month t distribut. % RCU*1 % grade % t distribut. % grade g/t kg distribut. % grade g/t kg distribut. % 1995 Run-of-mine ore January 6,172 100.0 88.2 1.7 105.4 100.0 2.2 13.3 100.0 9.4 58.0 100.0 February 5,271 100.0 75.3 2.2 115.3 100.0 1.1 6.0 100.0 9.8 51.5 100.0 March 7,517 100.0 107.4 2.6 192.6 100.0 0.8 6.0 100.0 12.6 94.9 100.0 April 6,674 100.0 95.3 2.3 151.1 100.0 0.6 4.3 100.0 14.9 99.6 100.0 May 5,810 100.0 83.0 2.2 127.0 100.0 1.5 8.8 100.0 23.0 133.7 100.0 June 4,005 100.0 57.2 2.8 113.2 100.0 1.4 5.5 100.0 21.1 84.5 100.0 July 6,514 100.0 93.1 1.9 120.6 100.0 0.7 4.7 100.0 15.0 97.6 100.0 August 6,110 100.0 87.3 1.7 106.0 100.0 1.3 8.2 100.0 12.3 75.3 100.0 September 4,441 100.0 63.4 1.6 68.8 100.0 1.6 7.3 100.0 13.9 61.6 100.0 October 6,670 100.0 95.3 2.0 130.7 100.0 1.3 8.5 100.0 18.8 125.2 100.0 November 5,976 100.0 85.4 2.2 129.5 100.0 1.6 9.5 100.0 19.0 113.6 100.0 December 5,090 100.0 72.7 2.2 109.4 100.0 1.8 9.0 100.0 19.0 96.6 100.0 Total 70,252 100.0 83.6 2.1 1,470 100.0 1.3 91.0 100.0 15.5 1,092.0 100.0 Cu concentrate January 390 6.3 25.2 98.4 93.4 22.0 8.6 64.3 121.6 47.5 81.9 February 292 5.5 31.8 92.8 80.5 18.8 5.5 92.1 165.4 48.3 93.9 March 512 6.8 29.6 151.2 78.5 7.8 4.0 66.1 169.7 86.8 91.4 April 509 7.6 26.4 134.5 89.0 5.5 2.8 65.0 193.6 98.6 99.0 3-53 May 483 8.3 25.7 124.0 97.7 13.5 6.5 74.3 238.2 115.1 86.1 June 363 9.1 26.5 96.3 85.0 11.7 4.3 77.4 217.7 79.1 93.6 July 429 6.6 26.6 114.1 94.6 8.7 3.7 80.3 221.8 95.1 97.5 August 420 6.9 23.5 98.8 93.2 14.2 6.0 73.0 174.0 73.0 97.0 September 260 5.9 23.5 61.3 89.0 18.4 4.8 66.1 209.0 54.4 88.4 October 416 6.2 26.8 111.4 85.3 19.5 8.1 95.0 255.9 106.4 85.0 November 448 7.5 27.8 124.6 96.2 18.2 8.2 85.7 195.4 87.6 77.1 December 440 8.6 24.3 106.6 97.4 17.4 7.6 84.5 209.0 91.9 95.1 Total 4,962 7.1 26.5 1,314 89.4 14.1 70.0 76.9 198.3 983.8 90.1 Tailing January 5,782 93.7 0.1 7.0 6.6 0.8 4.8 35.7 1.8 10.5 18.1 February 4,979 94.5 0.5 22.5 19.5 0.1 0.5 7.9 0.6 3.1 6.1 March 7,006 93.2 0.6 41.4 21.5 0.3 2.0 33.9 1.2 8.1 8.6 April 6,165 92.4 0.3 16.6 11.0 0.2 1.5 35.0 0.2 1.0 1.0 May 5,327 91.7 0.1 2.9 2.3 0.4 2.3 25.7 3.5 18.6 13.9 June 3,642 90.9 0.5 17.0 15.0 0.3 1.2 22.6 1.5 5.4 6.4 July 6,085 93.4 0.1 6.6 5.4 0.2 0.9 19.7 0.4 2.5 2.5 August 5,690 93.1 0.1 7.3 6.8 0.4 2.2 27.0 0.4 2.2 3.0 September 4,181 94.1 0.2 7.6 11.0 0.6 2.5 33.9 1.7 7.2 11.6 October 6,254 93.8 0.3 19.3 14.7 0.1 0.4 5.0 3.0 18.8 15.0 November 5,528 92.5 0.1 4.9 3.8 0.3 1.4 14.3 4.7 26.1 22.9 December 4,651 91.4 0.1 2.8 2.6 0.3 1.4 15.5 1.0 4.7 4.9 Total 65,290 92.9 0.2 156 10.6 0.3 21.0 23.1 1.7 108.2 9.9 Table 3-19 Result of Processing for Sulfide Copper Ore in 1996 at Ovalle plant, ENAMI *1: RCU Rate of capacity utilization(Cap.: 7,000t/month: 84,000t/year) Ore Tonnage Cu Au Ag Year Product Month t distribut. % RCU*1 % grade % t distribut. % grade g/t kg distribut. % grade g/t kg distribut. % 1996 Run-of-mine ore January 3,576 100.0 51.1 2.5 89.0 100.0 1.4 4.9 100.0 24.9 89.2 100.0 February 4,197 100.0 60.0 2.1 89.4 100.0 0.9 3.9 100.0 15.9 66.9 100.0 March 3,677 100.0 52.5 2.3 85.7 100.0 1.2 4.3 100.0 20.9 76.7 100.0 April 4,926 100.0 70.4 2.2 108.9 100.0 0.9 4.5 100.0 18.2 89.4 100.0 May 3,557 100.0 50.8 2.6 90.8 100.0 0.8 2.9 100.0 20.8 74.1 100.0 June 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 July 5,650 100.0 80.7 2.0 113.7 100.0 0.6 3.4 100.0 9.0 50.9 100.0 August 7,451 100.0 106.4 2.6 194.5 100.0 0.6 4.4 100.0 15.5 115.1 100.0 September 7,073 100.0 101.0 2.8 194.5 100.0 1.2 8.7 100.0 15.2 107.7 100.0 October 7,132 100.0 101.9 2.1 150.0 100.0 0.8 5.9 100.0 9.3 66.4 100.0 November 5,678 100.0 81.1 1.9 108.1 100.0 0.7 4.2 100.0 8.3 47.1 100.0 December 7,580 100.0 108.3 2.0 148.7 100.0 0.4 3.1 100.0 8.2 62.0 100.0 Total 60,498 100.0 72.0 2.3 1,373 100.0 0.8 50.2 100.0 14.0 845.4 100.0 Cu concentrate January 295 8.2 27.5 80.9 90.9 16.4 4.8 97.7 235.1 69.2 77.6 February 348 8.3 24.9 86.5 96.7 9.8 3.4 87.2 175.8 61.1 91.4 March 308 8.4 27.7 85.2 99.4 3.7 1.1 26.1 150.3 46.2 60.3 April 398 8.1 26.7 106.1 97.4 8.2 3.2 71.4 184.8 73.6 82.3 3-54 May 294 8.3 27.3 80.2 88.3 7.6 2.2 76.1 174.9 51.4 69.4 June 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 July 361 6.4 27.2 98.2 86.4 9.6 3.5 101.1 163.4 59.1 116.0 August 671 9.0 24.2 162.6 83.6 4.3 2.9 66.2 162.7 109.3 95.0 September 685 9.7 28.1 192.4 98.9 7.3 5.0 57.4 147.4 101.0 93.7 October 584 8.2 25.4 148.4 99.0 11.9 7.0 119.1 127.2 74.3 111.8 November 390 6.9 26.4 103.0 95.3 10.8 4.2 100.0 146.8 57.3 121.6 December 562 7.4 25.0 140.5 94.5 7.3 4.1 133.5 131.3 73.8 119.0 Total 4,896 8.1 26.2 1,284 93.5 8.5 41.5 82.5 158.5 776.2 91.8 Tailing January 3,282 91.8 0.3 8.1 9.1 0.0 0.1 2.3 6.1 20.0 22.4 February 3,849 91.7 0.1 3.0 3.3 0.1 0.5 12.8 1.5 5.7 8.6 March 3,369 91.6 0.0 0.5 0.6 1.0 3.2 73.9 9.0 30.4 39.7 April 4,528 91.9 0.1 2.8 2.6 0.3 1.3 28.6 3.5 15.8 17.7 May 3,263 91.7 0.3 10.6 11.7 0.2 0.7 23.9 7.0 22.7 30.6 June 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 July 5,289 93.6 0.3 15.5 13.6 0.0 -0.0 -1.1 -1.5 -8.2 -16.0 August 6,779 91.0 0.5 31.9 16.4 0.2 1.5 33.8 0.9 5.8 5.0 September 6,388 90.3 0.0 2.2 1.1 0.6 3.7 42.6 1.1 6.7 6.3 October 6,549 91.8 0.0 1.5 1.0 -0.2 -1.1 -19.1 -1.2 -7.9 -11.8 November 5,287 93.1 0.1 5.1 4.7 0.0 -0.0 0.0 -1.9 -10.2 -21.6 December 7,018 92.6 0.1 8.2 5.5 -0.2 -1.0 -33.5 -1.7 -11.8 -19.0 Total 55,602 91.9 0.2 89 6.5 0.2 8.8 17.5 1.2 69.2 8.2 Table 3-20 Result of Processing for Sulfide Copper Ore in 1997 at Ovalle plant, ENAMI *1: RCU Rate of capacity utilization(Cap.: 7,000t/month: 84,000t/year) Ore Tonnage Cu Au Ag Year Product Month t distribut. % RCU*1 % grade % t distribut. % grade g/t kg distribut. % grade g/t kg distribut. % 1997 Run-of-mine ore January 6,470 100.0 92.4 2.1 135.9 100.0 0.5 3.1 100.0 10.0 64.5 100.0 February 6,063 100.0 86.6 2.3 140.6 100.0 0.4 2.6 100.0 10.5 63.9 100.0 March 6,236 100.0 89.1 2.3 141.0 100.0 0.7 4.4 100.0 12.8 79.6 100.0 April 6,205 100.0 88.6 1.9 120.2 100.0 0.3 2.1 100.0 7.6 47.0 100.0 May 6,168 100.0 88.1 2.3 141.9 100.0 0.3 1.8 100.0 6.0 37.1 100.0 June 4,749 100.0 67.8 2.8 133.2 100.0 1.1 5.1 100.0 16.7 79.1 100.0 July 5,104 100.0 72.9 2.5 128.7 100.0 0.8 4.1 100.0 13.8 70.6 100.0 August 6,017 100.0 86.0 2.0 118.8 100.0 0.7 4.5 100.0 9.5 57.1 100.0 September 5,299 100.0 75.7 2.4 127.6 100.0 0.7 3.5 100.0 13.2 70.1 100.0 October 4,376 100.0 62.5 2.6 113.5 100.0 0.7 3.1 100.0 16.0 69.8 100.0 November 3,844 100.0 54.9 2.1 81.9 100.0 0.6 2.2 100.0 13.3 51.0 100.0 December 4,617 100.0 66.0 2.0 91.6 100.0 0.5 2.1 100.0 10.1 46.8 100.0 Total 65,148 100.0 77.6 2.3 1,475 100.0 0.6 38.5 100.0 11.3 736.6 100.0 Cu concentrate January 455 7.0 27.5 125.1 92.0 4.4 2.0 65.7 110.5 50.3 78.0 February 456 7.5 28.3 129.2 91.9 3.8 1.7 66.4 111.3 50.8 79.5 March 441 7.1 29.4 129.7 92.0 7.3 3.2 73.5 148.9 65.7 82.6 April 444 7.1 24.9 110.6 92.0 3.4 1.5 70.6 91.5 40.6 86.3 3-55 May 430 7.0 32.3 139.0 97.9 2.7 1.2 65.3 73.6 31.7 85.4 June 413 8.7 27.7 114.5 86.0 7.0 2.9 56.6 167.3 69.1 87.3 July 462 9.1 25.7 118.6 92.2 7.6 3.5 86.0 131.5 60.8 86.1 August 392 6.5 28.0 109.6 92.2 6.3 2.5 55.0 124.0 48.6 85.0 September 430 8.1 27.7 118.8 93.1 6.3 2.7 78.1 143.1 61.5 87.7 October 373 8.5 28.2 105.2 92.8 5.9 2.2 69.3 156.9 58.5 83.8 November 267 7.0 28.2 75.3 92.0 5.8 1.6 70.0 160.1 42.8 84.0 December 304 6.6 26.0 79.2 86.5 8.1 2.5 119.2 209.8 63.8 136.2 Total 4,868 7.5 27.8 1,355 91.9 5.6 27.4 71.1 132.3 644.1 87.4 Tailing January 6,015 93.0 0.2 10.9 8.0 0.2 1.0 34.3 2.4 14.2 22.0 February 5,607 92.5 0.2 11.4 8.1 0.2 0.9 33.6 2.3 13.1 20.5 March 5,795 92.9 0.2 11.2 8.0 0.2 1.2 26.5 2.4 13.9 17.4 April 5,761 92.9 0.2 9.6 8.0 0.1 0.6 29.4 1.1 6.4 13.7 May 5,737 93.0 0.1 2.9 2.1 0.1 0.6 34.7 0.9 5.4 14.6 June 4,336 91.3 0.4 18.7 14.0 0.5 2.2 43.4 2.3 10.1 12.7 July 4,642 90.9 0.2 10.1 7.8 0.1 0.6 14.0 2.1 9.8 13.9 August 5,625 93.5 0.2 9.3 7.8 0.4 2.0 45.0 1.5 8.6 15.0 September 4,869 91.9 0.2 8.8 6.9 0.2 0.8 21.9 1.8 8.6 12.3 October 4,003 91.5 0.2 8.2 7.2 0.2 1.0 30.7 2.8 11.3 16.2 November 3,577 93.0 0.2 6.6 8.0 0.2 0.7 30.0 2.3 8.2 16.0 December 4,313 93.4 0.3 12.4 13.5 -0.1 -0.4 -19.2 -3.9 -17.0 -36.2 Total 60,281 92.5 0.2 120 8.1 0.2 11.1 28.9 1.5 92.6 12.6 Table 3-21 Result of Processing for Sulfide Copper Ore in 1998 at Ovalle plant, ENAMI *1: RCU Rate of capacity utilization(Cap.: 7,000t/month: 84,000t/year) Ore Tonnage Cu Au Ag Year Product Month t distribut. % RCU*1 % grade % t distribut. % grade g/t kg distribut. % grade g/t kg distribut. % 1998 Run-of-mine ore January 3,493 100.0 49.9 1.9 65.9 100.0 0.8 2.9 100.0 10.3 36.1 100.0 February 1,777 100.0 25.4 2.1 37.8 100.0 0.4 0.7 100.0 7.4 13.1 100.0 March 2,210 100.0 31.6 1.5 33.0 100.0 0.6 1.3 100.0 3.3 7.3 100.0 April 2,554 100.0 36.5 1.3 34.3 100.0 0.4 1.0 100.0 3.9 9.8 100.0 May 3,158 100.0 45.1 1.5 47.4 100.0 0.3 0.9 100.0 4.7 14.8 100.0 June 2,213 100.0 31.6 3.3 73.8 100.0 0.8 1.8 100.0 25.4 56.2 100.0 July 5,489 100.0 78.4 3.6 197.8 100.0 0.7 3.9 100.0 20.9 114.6 100.0 August 5,171 100.0 73.9 2.6 136.3 100.0 1.0 5.2 100.0 7.8 40.6 100.0 September 4,690 100.0 67.0 4.5 209.4 100.0 1.4 6.6 100.0 19.9 93.2 100.0 October 3,725 100.0 53.2 4.4 162.9 100.0 0.5 2.0 100.0 17.2 64.1 100.0 November 7,016 100.0 100.2 2.8 196.4 100.0 0.4 2.4 100.0 6.7 47.1 100.0 December 6,137 100.0 87.7 3.3 201.9 100.0 0.7 4.0 100.0 9.1 55.6 100.0 Total 47,632 100.0 56.7 2.9 1,397 100.0 0.7 32.7 100.0 11.6 552.4 100.0 Cu concentrate January 239 6.8 25.3 60.4 91.7 10.4 2.5 84.6 128.3 30.6 84.9 February 129 7.2 26.4 34.0 89.9 3.7 0.5 70.5 71.0 9.1 69.9 March 130 5.9 24.4 31.7 96.0 6.6 0.9 67.7 110.4 14.4 195.7 April 146 5.7 20.7 30.2 88.2 2.3 0.3 35.6 107.1 15.6 159.0 3-56 May 187 5.9 22.4 41.9 88.2 3.9 0.7 81.4 46.3 8.7 58.6 June 290 13.1 21.1 61.2 83.0 4.1 1.2 66.0 131.9 38.2 68.0 July 629 11.5 26.2 165.0 83.4 4.2 2.6 68.0 146.4 92.1 80.3 August 520 10.0 23.0 119.4 87.6 6.9 3.6 68.0 117.9 61.3 151.1 September 742 15.8 24.9 185.2 88.4 6.0 4.4 66.8 86.1 63.9 68.6 October 312 8.4 45.6 142.4 87.4 16.6 5.2 258.2 283.5 88.5 138.1 November 681 9.7 26.9 183.3 93.3 4.4 3.0 123.8 111.1 75.7 160.5 December 688 11.2 28.7 197.0 97.6 3.7 2.5 62.6 91.3 62.8 112.9 Total 4,692 9.9 26.7 1,252 89.6 5.8 27.4 83.7 119.5 560.8 101.5 Tailing January 3,255 93.2 0.2 5.5 8.3 0.1 0.4 15.4 1.7 5.5 15.1 February 1,649 92.8 0.2 3.8 10.1 0.1 0.2 29.5 2.4 3.9 30.1 March 2,080 94.1 0.1 1.3 4.0 0.2 0.4 32.3 -3.4 -7.0 -95.7 April 2,408 94.3 0.2 4.1 11.8 0.3 0.6 64.4 -2.4 -5.8 -59.0 May 2,971 94.1 0.2 5.6 11.8 0.1 0.2 18.6 2.1 6.1 41.4 June 1,923 86.9 0.7 12.6 17.0 0.3 0.6 34.0 9.4 18.0 32.0 July 4,860 88.5 0.7 32.8 16.6 0.3 1.2 32.0 4.6 22.5 19.7 August 4,651 90.0 0.4 16.9 12.4 0.4 1.7 32.0 -4.5 -20.7 -51.1 September 3,947 84.2 0.6 24.3 11.6 0.6 2.2 33.2 7.4 29.3 31.4 October 3,412 91.6 0.6 20.5 12.6 -0.9 -3.2 -158.2 -7.2 -24.4 -38.1 November 6,335 90.3 0.2 13.2 6.7 -0.1 -0.6 -23.8 -4.5 -28.5 -60.5 December 5,449 88.8 0.1 4.9 2.4 0.3 1.5 37.4 -1.3 -7.2 -12.9 Total 42,940 90.1 0.3 145 10.4 0.1 5.3 16.3 -0.2 -8.4 -1.5 Table 3-22 Result of Processing for Sulfide Copper Ore in 1999 at Ovalle plant, ENAMI *1: RCU Rate of capacity utilization(Cap.: 7,000t/month: 84,000t/year) Ore TonnageCu Au Ag Year Product Month t distribut. % RCU*1 % grade % t distribut. % grade g/t kg distribut. % grade g/t kg distribut. % 1999 Run-of-mine ore January 5,540 100.0 79.1 2.3 127.8 100.0 0.1 0.7 100.0 1.2 6.5 100.0 February 4,334 100.0 61.9 1.7 74.9 100.0 0.3 1.3 100.0 0.0 0.0 0.0 March 5,686 100.0 81.2 1.6 91.4 100.0 0.2 0.9 100.0 1.9 10.9 100.0 April 5,225 100.0 74.6 1.5 80.5 100.0 0.2 0.9 100.0 2.4 12.4 100.0 May 2,168 100.0 31.0 2.1 45.5 100.0 0.0 0.1 100.0 2.4 5.1 100.0 June 3,221 100.0 46.0 2.1 67.6 100.0 0.0 0.0 100.0 2.8 9.0 100.0 July 3,978 100.0 56.8 2.1 84.1 100.0 0.0 0.0 100.0 3.1 12.4 100.0 August 1,978 100.0 28.3 2.0 40.1 100.0 -0.1 -0.1 100.0 3.7 7.3 100.0 September 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 October 3,442 100.0 49.2 1.7 58.9 100.0 0.3 0.9 100.0 3.5 11.9 100.0 November 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 December 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Total 35,572 100.0 42.3 1.9 671 100.0 0.1 4.6 100.0 2.1 75.4 100.0 Cu concentrate January 507 9.2 23.2 117.7 92.1 3.6 1.8 262.6 73.7 37.4 574.3 February 308 7.1 22.3 68.8 91.8 5.5 1.7 129.1 76.0 23.4 ----- March 348 6.1 22.4 78.0 85.3 2.5 0.9 102.9 67.6 23.5 216.2 April 341 6.5 21.4 72.9 90.5 2.7 0.9 105.2 93.0 31.7 256.3 3-57 May 202 9.3 21.2 42.8 94.0 2.5 0.5 752.2 96.0 19.4 378.2 June 305 9.5 21.0 64.1 94.9 2.3 0.7 10200.0 95.6 29.2 323.9 July 334 8.4 21.5 72.0 85.6 2.4 0.8 3631.8 128.8 43.0 346.8 August 164 8.3 22.5 36.8 91.8 1.7 0.3 -218.6 95.6 15.6 215.6 September 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 October 239 7.0 21.9 52.4 89.1 2.4 0.6 66.5 100.4 24.0 202.5 November 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 December 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Total 2,749 7.7 22.0 605 90.3 3.0 8.2 179.8 90.0 247.3 327.8 Tailing January 5,033 90.8 0.2 10.0 7.9 -0.2 -1.1 -162.6 -6.1 -30.9 -474.3 February 4,026 92.9 0.2 6.2 8.2 -0.1 -0.4 -29.1 -5.8 -23.4 ----- March 5,338 93.9 0.3 13.5 14.7 0.0 -0.0 -2.9 -2.4 -12.7 -116.2 April 4,884 93.5 0.2 7.6 9.5 0.0 -0.0 -5.2 -4.0 -19.4 -156.3 May 1,966 90.7 0.1 2.7 6.0 -0.2 -0.4 -652.2 -7.3 -14.3 -278.2 June 2,916 90.5 0.1 3.5 5.1 -0.2 -0.7 -10100.0 -6.9 -20.2 -223.9 July 3,643 91.6 0.3 12.1 14.4 -0.2 -0.8 -3531.8 -8.4 -30.6 -246.8 August 1,814 91.7 0.2 3.3 8.2 -0.2 -0.4 318.6 -4.6 -8.4 -115.6 September 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 October 3,203 93.0 0.2 6.4 10.9 0.1 0.3 33.5 -3.8 -12.2 -102.5 November 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 December 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Total 32,823 92.3 0.2 65 9.7 -0.1 -3.6 -79.8 -5.2 -171.9 -227.8 Table 3-23 Result of Processing for Sulfide Copper Ore in 2000 at Ovalle plant, ENAMI *1: RCU Rate of capacity utilization(Cap.: 7,000t/month: 84,000t/year) Ore Tonnage Cu Au Ag Year Product Month t distribut. % RCU*1 % grade % t distribut. % grade g/t kg distribut. % grade g/t kg distribut. % 2000 Run-of-mine ore January 4,968 100.0 71.0 2.1 106.5 100.0 0.1 0.5 100.0 6.8 33.6 100.0 February 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 March 6,575 100.0 93.9 1.7 110.8 100.0 0.2 1.0 100.0 1.9 12.8 100.0 April 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 May 5,584 100.0 79.8 1.6 89.5 100.0 0.1 0.7 100.0 2.3 12.7 100.0 June 3,135 100.0 44.8 1.9 59.7 100.0 0.1 0.4 100.0 7.3 22.8 100.0 July 3,706 100.0 52.9 1.5 57.1 100.0 0.2 0.9 100.0 1.6 6.1 100.0 August 4,256 100.0 60.8 1.8 75.2 100.0 0.4 1.6 100.0 3.1 13.1 100.0 September 3,614 100.0 51.6 1.7 60.9 100.0 0.3 1.2 100.0 0.4 1.6 100.0 October 5,463 100.0 78.0 1.5 79.1 100.0 1.0 5.4 100.0 2.3 12.3 100.0 November 5,685 100.0 81.2 1.5 87.8 100.0 0.4 2.1 100.0 3.3 18.6 100.0 December 4,433 100.0 63.3 1.9 84.3 100.0 0.3 1.1 100.0 7.6 33.7 100.0 Total 47,418 100.0 56.4 1.7 811 100.0 0.3 14.9 100.0 3.5 167.1 100.0 Cu concentrate January 437 8.8 21.6 94.3 88.5 1.1 0.5 87.5 98.0 42.8 127.3 February 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 March 419 6.4 22.6 94.6 85.4 1.0 0.4 40.3 90.3 37.8 296.0 April 0 0.0 0.0 0.0 0.0 0.0 0.1 ----- 0.0 4.7 ----- 3-58 May 342 6.1 22.5 76.9 85.9 1.3 0.4 60.0 69.3 23.7 187.2 June 233 7.4 22.4 52.3 87.7 0.9 0.2 46.7 84.6 19.8 86.8 July 219 5.9 22.6 49.4 86.5 0.4 0.1 10.1 99.4 21.7 358.0 August 278 6.5 22.5 62.5 83.1 2.2 0.6 38.5 50.5 14.0 107.2 September 225 6.2 21.8 49.1 80.7 0.9 0.2 16.6 110.9 25.0 1578.7 October 283 5.2 22.4 63.3 80.0 8.5 2.4 44.1 86.6 24.5 198.5 November 320 5.6 21.6 69.1 78.7 3.1 1.0 48.1 80.1 25.6 138.0 December 313 7.1 23.0 72.1 85.5 1.4 0.4 38.5 100.3 31.4 93.0 Total 3,068 6.5 22.3 684 84.3 2.0 6.3 42.1 88.3 270.9 162.1 Tailing January 4,531 91.2 0.3 12.2 11.5 0.0 0.1 12.5 -2.0 -9.2 -27.3 February 0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 March 6,156 93.6 0.3 16.2 14.6 0.1 0.6 59.7 -4.1 -25.0 -196.0 April 0 0.0 0.0 0.0 0.0 0.0 -0.1 0.0 0.0 -4.7 0.0 May 5,241 93.9 0.2 12.6 14.1 0.1 0.3 40.0 -2.1 -11.1 -87.2 June 2,902 92.6 0.3 7.4 12.3 0.1 0.2 53.3 1.0 3.0 13.2 July 3,487 94.1 0.2 7.7 13.5 0.2 0.8 89.9 -4.5 -15.7 -258.0 August 3,978 93.5 0.3 12.7 16.9 0.2 1.0 61.5 -0.2 -0.9 -7.2 September 3,389 93.8 0.4 11.8 19.3 0.3 1.0 83.4 -6.9 -23.4 -1478.7 October 5,180 94.8 0.3 15.8 20.0 0.6 3.0 55.9 -2.3 -12.1 -98.5 November 5,365 94.4 0.4 18.7 21.3 0.2 1.1 51.9 -1.3 -7.0 -38.0 December 4,120 92.9 0.3 12.2 14.5 0.2 0.7 61.5 0.6 2.3 7.0 Total 44,350 93.5 0.3 127 15.7 0.2 8.6 57.9 -2.3 -103.7 -62.1 Table 3-24 Result of Processing for Sulfide Copper Ore in 2001 at Ovalle plant, ENAMI *1: RCU Rate of capacity utilization(Cap.: 7,000t/month: 84,000t/year) Ore Tonnage Cu Au Ag Year Product Month t distribut. % RCU*1 % grade % t distribut. % grade g/t kg distribut. % grade g/t kg distribut. % 2001 Run-of-mine ore January 4,410 100.0 63.0 1.8 79.5 100.0 0.3 1.2 100.0 7.1 31.2 100.0 February 3,002 100.0 42.9 1.8 53.1 100.0 0.2 0.7 100.0 5.2 15.5 100.0 March 5,509 100.0 78.7 1.7 92.9 100.0 0.3 1.6 100.0 2.7 15.1 100.0 April 5,593 100.0 79.9 1.7 96.7 100.0 0.3 1.6 100.0 0.8 4.3 100.0 May 4,378 100.0 62.5 2.3 102.2 100.0 0.4 1.7 100.0 0.5 2.1 100.0 June July August September October November December Total 22,892 100.0 65.4 1.9 424 100.0 0.3 6.8 100.0 3.0 68.2 100.0 Cu concentrate January 284 6.4 23.1 65.4 82.3 1.5 0.4 35.9 102.7 29.1 93.2 February 192 6.4 22.6 43.3 81.5 1.0 0.2 25.9 92.3 17.7 114.5 March 363 6.6 21.4 77.8 83.7 1.0 0.4 23.9 91.2 33.1 219.5 April 483 8.6 20.7 100.1 103.6 1.3 0.6 39.6 85.6 41.3 962.8 3-59 May 388 8.9 23.3 90.5 88.5 2.0 0.8 44.2 119.5 46.3 2,158.8 June July August September October November December Total 1,709 7.5 22.1 377 88.9 1.4 2.4 35.1 98.0 167.6 245.6 Tailing January 4,126 93.6 0.3 14.1 17.7 0.2 0.8 64.1 0.5 2.1 6.8 February 2,810 93.6 0.4 9.8 18.5 0.2 0.5 74.1 -0.8 -2.2 -14.5 March 5,145 93.4 0.3 15.1 16.3 0.2 1.2 76.1 -3.5 -18.0 -119.5 April 5,111 91.4 -0.1 -3.4 -3.6 0.2 1.0 60.4 -7.2 -37.0 -862.8 May 3,990 91.1 0.3 11.7 11.5 0.2 1.0 55.8 -11.1 -44.2 -2058.8 June July August September October November December Total 21,182 92.5 0.2 47 11.1 0.2 4.4 64.9 -4.7 -99.3 -145.6 Table 3-26 Result of RCU for Processing of Sulfide Copper Ore at Ovalle plant, ENAMI Note RCU: Rate of capacity utilization (Cap.: 7,000t/month: 84,000t/year) Cu Metal Price: LME Grade A Settlement (Original: ～93.6: £ /MT, 93.7～: $/MT) Ore Tonnage Cu Cu Metal Year Product Month t RCU % grade % t LME ¢ /lb 1994 Run-of-mine ore January 5,191 74.2 3.1 158.1 81.89 February 6,092 87.0 2.9 176.1 84.12 March 6,503 92.9 2.4 153.2 86.86 April 6,414 91.6 3.3 209.9 85.36 May 6,796 97.1 2.2 152.0 97.55 June 6,192 88.5 2.0 122.6 107.24 July 7,070 101.0 2.3 159.5 111.50 August 6,830 97.6 2.2 150.7 109.15 September 7,555 107.9 2.0 148.2 113.67 October 7,883 112.6 2.1 168.3 115.52 November 7,368 105.3 2.0 149.3 127.03 December 6,302 90.0 1.5 93.8 135.35 Total 80,196 95.5 2.3 1,842 104.60 1995 Run-of-mine ore January 6,172 88.2 1.7 105.4 136.48 February 5,271 75.3 2.2 115.3 130.53 March 7,517 107.4 2.6 192.6 132.63 April 6,674 95.3 2.3 151.1 131.70 May 5,810 83.0 2.2 127.0 125.80 June 4,005 57.2 2.8 113.2 135.84 July 6,514 93.1 1.9 120.6 139.51 August 6,110 87.3 1.7 106.0 137.75 September 4,441 63.4 1.6 68.8 132.25 October 6,670 95.3 2.0 130.7 127.62 November 5,976 85.4 2.2 129.5 135.05 December 5,090 72.7 2.2 109.4 132.73 Total 70,252 83.6 2.1 1,470 133.16 1996 Run-of-mine ore January 3,576 51.1 2.5 89.0 118.68 February 4,197 60.0 2.1 89.4 115.11 March 3,677 52.5 2.3 85.7 116.17 April 4,926 70.4 2.2 108.9 117.74 May 3,557 50.8 2.6 90.8 120.58 June 0 0.0 0.0 0.0 90.27 July 5,650 80.7 2.0 113.7 90.06 August 7,451 106.4 2.6 194.5 91.11 September 7,073 101.0 2.8 194.5 88.06 October 7,132 101.9 2.1 150.0 88.96 November 5,678 81.1 1.9 108.1 101.19 December 7,580 108.3 2.0 148.7 102.88 Total 60,498 72.0 2.3 1,373 104.09 1997 Run-of-mine ore January 6,470 92.4 2.1 135.9 110.45 February 6,063 86.6 2.3 140.6 109.13 March 6,236 89.1 2.3 141.0 109.83 April 6,205 88.6 1.9 120.2 108.46 May 6,168 88.1 2.3 141.9 114.05 June 4,749 67.8 2.8 133.2 118.51 July 5,104 72.9 2.5 128.7 111.15 August 6,017 86.0 2.0 118.8 102.11 September 5,299 75.7 2.4 127.6 95.59 October 4,376 62.5 2.6 113.5 93.09 November 3,844 54.9 2.1 81.9 86.97 December 4,617 66.0 2.0 91.6 79.94 Total 65,148 77.6 2.3 1,475 103.27

3-60 1998 Run-of-mine ore January 3,493 49.9 1.9 65.9 76.59 February 1,777 25.4 2.1 37.8 75.51 March 2,210 31.6 1.5 33.0 79.29 April 2,554 36.5 1.3 34.3 81.69 May 3,158 45.1 1.5 47.4 78.58 June 2,213 31.6 3.3 73.8 75.32 July 5,489 78.4 3.6 197.8 74.89 August 5,171 73.9 2.6 136.3 73.52 September 4,690 67.0 4.5 209.4 74.74 October 3,725 53.2 4.4 162.9 71.96 November 7,016 100.2 2.8 196.4 71.39 December 6,137 87.7 3.3 201.9 66.84 Total 47,632 56.7 2.9 1,397 75.05 1999 Run-of-mine ore January 5,540 79.1 2.3 127.8 64.92 February 4,334 61.9 1.7 74.9 63.99 March 5,686 81.2 1.6 91.4 62.52 April 5,225 74.6 1.5 80.5 66.50 May 2,168 31.0 2.1 45.5 68.55 June 3,221 46.0 2.1 67.6 64.52 July 3,978 56.8 2.1 84.1 74.39 August 1,978 28.3 2.0 40.1 74.74 September 0 0.0 0.0 0.0 79.39 October 3,442 49.2 1.7 58.9 78.21 November 0 0.0 0.0 0.0 78.36 December 0 0.0 0.0 0.0 80.05 Total 35,572 42.3 1.9 671 71.34 2000 Run-of-mine ore January 4,968 71.0 2.1 106.5 83.64 February 0 0.0 0.0 0.0 81.69 March 6,575 93.9 1.7 110.8 78.90 April 0 0.0 0.0 0.0 76.15 May 5,584 79.8 1.6 89.5 80.99 June 3,135 44.8 1.9 59.7 79.52 July 3,706 52.9 1.5 57.1 81.62 August 4,256 60.8 1.8 75.2 84.18 September 3,614 51.6 1.7 60.9 88.92 October 5,463 78.0 1.5 79.1 86.12 November 5,685 81.2 1.5 87.8 81.43 December 4,433 63.3 1.9 84.3 83.94 Total 47,418 56.4 1.7 811 82.26 2001 Run-of-mine ore January 4,410 63.0 1.8 79.5 81.08 February 3,002 42.9 1.8 53.1 80.09 March 5,509 78.7 1.7 92.9 78.87 April 5,593 79.9 1.7 96.7 75.49 May 4,378 62.5 2.3 102.2 73.30 Total 22,892 65.4 1.9 424 76.97

3-61 Table 3-28 Target of Processing for Sulfide Copper Ore：Ovalle Plant, ENAMI

For the year In 2000 In 1994～2000 Measures Difference：Ｘ－Ｙ Target：Ｘ Result：Ｙ Results or expected outside circumference(◇) 1. Rate of capacity utilization: RCU % 90.0 56.4 42.3～95.5: Ave.69.2 +33.6 1) Incentive for custom ore by ENAMI t/year 75,600 47,418 35,572～80,196: Ave.58,128 +28,182 2) Management of mine by ENAMI (1) Ore tonnage (grade of Cu) (Cu-%) (same as in the right) (1.7) (1.7～2.9: Ave.2.2) (±0) 3) Decrease of cut-off grade of custom ore (2) Capacity t/year 84,000 84,000 84,000 ±0 4) Copper metal price >80～90¢ /lb (◇)

2. Recovery rate 1) Adoption of optimum circuit of grinding (1) Copper % 91.0 84.384.3～93.5: Ave.89.9 +5.7 2) Reservation of flotation time by pulp density up (2) Gold % --- 42.1 42.1～179.8?: Ave.88.4 --- (ditto) (3) Silver % --- 162.1? 87.1～327.8?: Ave.135.4? --- (ditto)

3-62 3. Product: copper concentrate (1) Quantity of copper concentrate 1) Quant. t/year Calculation 3,898 3,068 2,749～5,698: Ave.4,419 +788 1) Improvement of cleaning flow, and adoption 1) Grade % 30.0 22.3 22.0～29.1: Ave.26.4 +7.7 (2) Grade and quantity of Cu regrinding at cleaning, 2) Adoption column flotation 2) Quant. t/year Calculation 1,170 684 605～1,658: Ave.1,165 +473 machine at cleaning 1) Grade g/t --- 2.0 2.0～14.4: Ave.8.5 --- (3) Grade and quantity of Au (ditto) 2) Quant. kg/year --- 6.3 6.3～81.9: Ave.37.5 --- 1) Grade g/t --- 88.3 88.3～198.3: Ave.140.2 --- (4) Grade and quantity of Ag (ditto) 2) Quant. kg/year --- 270.9 247.3～983.8: Ave.619.5 ---

4. Income [Ａ]：estimation (*1) US$/year 1,015,368～951,003 493,362 +522,006～+457,641 from ENAMI

5. Production cost [Ｂ] US$/year 1,204,308 795,200 +409108 US$/crude ore t 15.93 16.77 -0.84 (1) Production unit cost 1) Reduction of cost of 5% for every item. (¢ /prod.Cu-lb) (Calculation 47.2) (Calculation 52.7) (-5.5)

6. Production gross profit [Ａ－Ｂ] US$/year -188,940～-253,305 -301,838 +112,898～+48,533 ＜Improved money for operation＞ US$/year +280,326～+277,922 Note *1：Proportion (①＋②) of processing ore tonnage: Target [supposition] ① 60～30% in case of purchase with fixed price , ② 40～70% in case of purchase with special contract, Result of Feb. 2000: ① 50%, ② 50% 3.3 Examination on Environmental Situation

3.3.1 Purpose The purpose of this examination is to survey the current environmental situation (water, soil, and air) around the Ovalle plant and to trace the roots of the pollution problems. The following points have been cleared so far, but further studies and compiling of monitoring data shall be carried out to take some countermeasures for the protection of the environment.

3.3.2 Water System and Quality around Ovalle As we have explained in the progress report (September. 2000), water system in this area is illustrated in Figure 3-9 topographical map. One of the major rivers, the Ingenio flows southwest-ward along and joins the river Limari at the lower reaches 40 km from the Ovalle plant. There is spring water near the plant (eastern bank on the upper reaches of Ingenio) that is the only water for drinking in this area. This is mountain area, 600 ～ 1000 m high around the plant. As the annual rainfall is as little as 80 ～ 100 mm, there is a little vegetation. Valleys and swamps are usually dry unless rain falls.

3.3.3 Water Quality･Monitoring Analysis The following 9 sites were selected as monitoring (observation) points around the plant. M-1: The Ingenio river (the upper stream of the plant) M-2: Spring Water for Drinking. M-3: Industrial water (Talhuen water) M-4: Waste solution from precipitation process. M-4A: Infiltrate drainage at downstream of evaporation pond M-4B: Infiltrate drainage at upstream of evaporation pond M-5: The Ingenio River (500 m down stream of the plant) M-6: The Ingenio River ( 2 Km down stream of the plant) M-7: The Ingenio River ( 5 Km down stream of the plant) Water quality at the above points shall be checked and compiled as basic data once a month by Chilean side for environmental assessment. The monthly results from Dec.1999 to Feb.2002 are shown in Table 3-29 through 3-55 respectively. (The analytical work on monitoring point M-4A and M-4B has been started from march.2000.) In M-1, M-2 and M-3, the upper reaches of the plant, water quality is stable through the year. The content of T-Fe at M-1, M-2,M-3 is 0 ～ 0.3 mg/L that is under the standard for Irrigation Water. (Shown in Figure 3-10) and higher content of Cl－at M-2 will be affected by chlorination of drinking water. As to the group of pollution roots (M-4, M-4A and M-4B), water quality of M-4 (waste solution from leaching process) is very instable. The content of T-Fe fluctuates from 9g/L to

3-63

Figure 3-9 Topographic Map

3-64 39g/L that is caused by instable operation in the oxide ore treating process. (Shown in Figure 3-11) The content of T-Fe is a key factor for operating new plant because Fe-ion shall keep the activity of iron oxidizing bacteria. M-4A seems to be penetrated from the evaporating ponds and diluted a little with surrounding water. M-4B is different from M-4A and M-4, seems to be penetrated mainly from the plant. As to M-5, M-6, M-7, the Ingenio River flow increase in April until September, then the water of M-5, M-6 and M-7 are diluted much and the density of the contaminants decrease in these 2- season. But at M-5, M-6, the each content of T-Fe, Cu, Al, Mn and SO4 are very high through the year. Then finally, at M-7, the each content of T-Fe, Cu, Al is decreasing by the effect of natural purification. (Shown in Figure 3-12)

3.3.4 Countermeasures against Water, Soil and Air Pollution (1) Waste Water ／Irrigation Water Standard in Chile Table 3-56 Standard for Industrial Waste Water･Waste Liquid /Irrigation Water (metal mining concerned) Standard for Waste Liquid Contaminant Unit Standard for No.1: No.2: No.3: No.4: No.5: Standard for (Regulatory discharge of Into Into the river Into Within a Without a Irrigation Substance) industrial river considered to lake protected protected Water waste water have a dilute- coastal sea coastal sea into sewer capacity area area pH 5.5－9.0 6.0－ 6.0－8.5 6.0－ 6.0－9.0 5.5－9.0 5.5－9.0 8.5 8.5 Temperature ℃ 35 35 40 30 30 - - Total suspended solid mg/L 300 80 300 80 100 700 - Sedimentary solid ml/L 20 - - 5 5 50 - 1h Al mg/L 10 5 10 1 1 10 5 As mg/L 0.5 0.5 1 0.1 0.2 0.5 0.1 B mg/L 40.75 3- - - 0.75 Cd mg/L 0.5 0.01 0.3 0.02 0.02 0.5 0.01 CN‐ mg/L 10.2 1 0.5 0.5 1 0.2 Cl‐ mg/L -400 2,000 - - - 200 Cu mg/L 3- -- 1 3 0.2 T-Cu mg/L -1 30.1 - - - T-Cr mg/L 10 - - 2.5 2.5 10 0.2 Cr6+ mg/L 0.5 0.05 0.2 0.2 0.2 0.5 - Sn mg/L -- - 0.5 0.5 1 - F mg/L -1.5 5 1 1.5 6 1 Fe mg/L -5 10 2 10 - 5 Mn mg/L 40.3 30.5 2 4 0.2 Hg mg/L 0.02 0.001 0.01 0.005 0.005 0.02 0.001 Mo mg/L -1 2.5 0.07 0.1 0.5 0.01 Ni mg/L 40.2 30.5 2 4 0.2 Pb mg/L 10.05 0.5 0.2 0.2 1 5 Se mg/L -0.01 0.1 0.01 0.01 0.03 0.02 2‐ SO4 mg/L 1,000 1,000 2,000 1,000 - - 250 S2‐ mg/L 51 10 1 1 5 - Zn mg/L 53 20 5 5 5 2

3-65 The new waste water standard of Chile was published on March 2001. "The standard for the river which is considered to have a dilute-capacity" shown in No.2 of above table or "Discharge standards into underground water" enactment schedule in 2003, should be applied to the waste solution from the Ovalle plant. In this new regulation, these new standard will come into effect on existing plants such as Ovalle Plant after 5 years. That means this new standard will act after 2006 in this law. On the other hand, in the case of Irrigation Water Standard applied, the each content of T-Fe, 2- 2- Cu, Al, Mn and SO4 in Ingenio river at M-5, M-6 and the content of Mn and SO4 at M-7 are exceeding Irrigation Water Standard and It seems that Ingenio river (M-5, M-6, M-7) is not good for Irrigation Water.

(2) Countermeasures against Water Pollution The total volume of M-4 penetrating into the Ingenio River is estimated in Table 3-57 below by the flux volume difference of T-Fe between M-1 (the upper stream of the plant) and M-5 (500 m down stream of the plant). (Shown in Fig 3-13) Table 3-57 Calculated Flux Volume of Penetrating Drainage (M-4) T-Fe[mg/s] M-4 (M-5)-(M-1) T-Fe[mg/L] Q [L/s] Dec 39,088 29,550 1.32 Jan. 2000 28,164 17,240 1.63 Feb 44,379 - - Mar 52,784 39,290 1.34 Apr 35,989 37,040 0.97 May 84,746 25,340 3.34 Jun 87,145 24,830 3.51 Jul 34,820 14,570 2.39 Aug 30,741 18,670 1.65 Sep 91,931 15,100 6.09 Oct 56,415 11,140 5.06 Nov 30,871 16,000 1.93 Dec 20,256 19,590 1.03 Jan. 2001 21,970 18,660 1.18 Feb 22,245 28,620 0.78 Mar 24,889 25,600 0.97 Apr 28,220 25,000 1.13 May 81,895 14,390 5.69 Jun 3,130 15,000 0.21 Jul 33,741 23,470 1.44 Aug 10,041 9,800 1.02 Sep 7,772 15,400 0.50 Oct 16,559 17,110 0.97 Nov 33,970 12,150 2.80 Dec 60,910 10,700 5.69 Jan. 2002 56,455 15,000 3.76 Feb 127,686 18,000 7.09

3-66 The total volume of M-4 penetrating into the Ingenio River is affected by the plant operation ratio and seasonal rainfall. As shown in Table 3-57, the penetrating volume of M-4 comes to 3 ～ 7 L/sec. But otherwise it comes around 1 L/sec or less. 2‐ Contaminants in M-4, T-Fe, Cu, Al, Mn, As, Zn, Cd, SO4 , in M-4A, T-Fe, Cu, Al, Mn, Zn, 2‐ 2‐ Cd, SO4 and in M-4B, Cu, Al, Mn, Zn, SO4 are exceeding the Waste Water standard. And it will become harder in the case of Irrigation Water standard applied. T-Fe, Cu, Al, Mn, 2‐ 2‐ As, Zn, Cd, SO4 in M-5 and M-6, Mn, Zn, SO4 in M-7 are exceeding that standard. The route of waste water penetrating from plant into the Ingenio River should be complicated. But the waste water of M-4A and M-4B always flow under the dike of the evaporating ponds. It is sure that M-4A and M-4B flow into the Ingenio River. Analytical result shows that M-4B might be the water coming together from inside of the plant and has less effect on the Ingenio River contamination. But M-4A will be the major pollution source of the Ingenio River contamination. It is penetrating from evaporating pond where M-4 water is fully stored. The following countermeasures should be examined and applied at the Ovalle Plant in order to prevent the water pollution until 2006 when the new regulation comes into effect.

① Lining HDPE(High Density Poly-Ethylene) sheet inside of the evaporating pond ; To prevent the penetration from the evaporating pond, cover the impervious layer such as HDPE sheet inside of the pond. ② Reforming the dike of the evaporating pond ; Reform the broken parts or rainwash of the dike and analyze the stability of the dike ③ Reforming the surroundings of the evaporating pond ; Reform the leaching waste and cover the soil, then vegetate on them ④ Arrangement of the channel ; Set up the open channels around the plant and the pond to shut down the flood of rainfall. ⑤ Study on the stability of the neutralized sediment ; Examine the stability of the neutralized sediment by dissolution test and fluidity test in case of containing much water.

(3) Countermeasures against Soil Pollution The ferric sediments containing some metals, leaching waste, tailing, and accumulated dusts etc in the Ingenio River possibly cause soil pollution around the Ovalle Plant. Especially, a large amount of ferric sediments (hydrated iron) is accumulating widely in the river from the monitoring point M-5 (500 m down stream of the plant) to M-7 (5 Km down stream of the plant). In the future, when the total volume of the waste water (M-4) from the leaching plant is properly treated and these countermeasures mentioned above is completed, soil pollution around the Ovalle Plant would be prevented. And moreover, it will take much time that new fresh sediments coming from upper stream of Ingenio River will cover the old polluted sediments gradually and naturally.

3-67 If all polluted sediments in the Ingenio River would be removed, it must require a huge cost and much time. Otherwise, actual damages to living life of the residents around the Ovalle Plant are not reported at the moment. It is quite reasonable to make use of these natural forces.

(4) Countermeasures against Air Pollution The dusts from the crushing process, acid mist from spraying and the dusts from the residue or the neutralized sediments in the evaporating ponds are all likely to cause air pollution around the Ovalle Plant. There are some vineries around the Ovalle Plant. It is required to prevent the scattering of these dusts as much as possible. The followings are recommended as the countermeasures. ・ Spraying on the crushing, agglomeration and transportation process to prevent the scattering of dusts. ・ Setting windbreak-net etc to prevent acid mist from spraying on leaching pad. ・ Reforming, soil-covering and vegetation should be applied on leaching wastes, tailings, the residue or the neutralized sediments in the evaporating ponds.

For reference： The followings are the Environmental Standard (Maximum Permitted Concentration) for Air Pollution in Chile.

＜The Primary Standard：To Protect Human Health＞ Floating Particles Arithmetic Average 150μg /Nm3 Concentration /Day Sulfurous Acid Gas Arithmetic Average 80μg /Nm3 Concentration /Year Arithmetic Average 365μg /Nm3 Concentration /Day

＜The Second Standard：To Protect Wildlife and Renewable Natural Resources＞ a. The North of Santiago Sulfurous Acid Gas Arithmetic Average 80μg /Nm3 Concentration /Year Arithmetic Average 365μg /Nm3 Concentration /Day Maximum 1,000μg /Nm3 Concentration /Hour

b. The South of Santiago Sulfurous Acid Gas Arithmetic Average 60μg /Nm3 Concentration /Year Arithmetic Average 260μg /Nm3 Concentration /Day Maximum 700μg /Nm3 Concentration /Hour ＊This standard is not applied for Santiago city and industrial towns.

3-68 There is no standard for Floating Particles in this part. But another standard for Floating Particles can be suggested in Ministry of Agriculture.

＜The Standard for Discharge＞ a. Sulfurous Acid Gas and Floating Particles There is no common standard for discharge. But it is regulated separately in each area that the maximum concentration of Sulfurous Acid Gas and Floating Particles must not exceed the Environmental Standard.

b. Arsenic The Regulation for Sulfurous Acid Gas and Floating Particles was settled by mining ministerial ordinance No 185 in 1992 as mentioned above. But the only regulation for Arsenic has been discussed continuously, it was settled by mining ministerial ordinance No 165 in 1998 at last. Sulfurous Acid Gas and Floating Particles is regulated by the concentration of the environmental standard. But Arsenic is regulated by the gross weight of discharge to the air that is maximum permitted volume.

Everywhere in Chile, when arsenic compound is newly discharged at any point, only 5% of additional discharge is allowable in weight to the total content of arsenic. Especially, if the arsenic is derived from some copper compounds, additional discharge must be under 0.024% in weight to the total arsenic. Followings are the maximum permitted discharge of arsenic at several industrial points.

Table 3-58 Maximum Permitted Discharge Volume of Arsenic at Existing Discharge Points Region・Provincce Production Existing Cu refinery Maximum permitted discharge Capacity /gold mine volume of arsenic (t/year ) (over t/year) 2000 2001 2003 ⅡRegion El Loa 1,400,000 Chuquicamata 1,100 800 400 ⅡRegion Antofagasta 350,000 Altonorte 126 126 126 ⅢRegion Copiapo 200,000 Paipote 42 42 42 ⅢRegion Chanaral 500,000 Potrerillios 1,450 800 150 ⅣRegion Elqul 80,000 Elindio 200 200 200 ⅤRegion San Felipe 350,000 Chagres 95 95 95 ⅤRegion Valparaiso 400,000 Ventanas 120 120 120 ⅥRegion Cachapoal 1,100,000 Caletones 1,880 375 375

3-69 T‐Fe mg/L Cl mg/L SO4 mg/L Q [ L/sec]

400 140 M-2 350 120

300 M-1 100 250 80 200 mg/L L/sec M-3 60 150 40 100

50 20

0 0

c r t c r t c c r t c r t c c r t c r t c eb n g eb n g eb eb n g eb n g eb eb n g eb n g eb De F Ap Ju Au Oc De F Ap Ju Au Oc De F De F Ap Ju Au Oc De F Ap Ju Au Oc De F De F Ap Ju Au Oc De F Ap Ju Au Oc De F Figure3-10 M-1, M-2, M-3 Monitoring Point Analysis ('99 Dec～'02 Feb)

*Standards : For Irrigation Water Ingenio river (upper) Drinking water

T‐Fe mg/L Cl mg/L SO4 mg/L Q [ L/sec] T‐Fe mg/L Cl mg/L SO4 mg/L Standards 5.0 200 250 Jan-2001 < 0.1 82 163 Dec 0.05 39 155 13.50 Feb < 0.1 122 180 Jan-2000 0.28 153 10.41 Mar < 0.1 96 228 Feb 0.05 < 10.0 124 17.74 Apr < 0.1 105 176 Mar 0.10 75 120 27.26 May < 0.1 92 150 Apr 0.05 70 94 26.89 Jun < 0.1 85 141 May 0.23 78 115 35.58 Jul < 0.1 88 169 Jun 0.22 74 96 130.87 Aug < 0.1 91 156 Jul 0.34 95 127 53.91 Sep < 0.1 116 171 Aug < 0.1 64 122 47.92 Oct < 0.1 110 176 Sep < 0.1 71 114 57.84 Nov < 0.1 109 137 Oct < 0.1 71 119 13.87 Dec < 0.1 97 119 Nov < 0.1 62 149 7.55 Jan-2002 0.20 115 183 Dec < 0.1 69 132 6.08 Feb 0.20 - 174 Jan-2001 < 0.1 49 161 13.44 Industrial water

Feb < 0.1 57 166 17.76 T‐Fe mg/L Cl mg/L SO4 mg/L Mar < 0.1 58 156 16.05 Standards 5.0 200 250 Apr < 0.1 61 139 16.97 Dec 0.00 44 117 May < 0.1 48 135 22.89 Jan-2000 0.00 180 Jun < 0.1 41 117 37.84 Feb Jul < 0.1 52 146 83.80 Mar 0.00 10 78 Aug < 0.1 44 116 61.63 Apr 0.00 12 71 Sep < 0.1 53 127 25.29 May 0.00 15 92 Oct < 0.1 61 129 14.47 Jun Nov < 0.1 60 101 12.46 Jul Dec < 0.1 68 100 11.71 Aug 0.10 12 84 Jan-2002 < 0.1 65 142 10.40 Sep Feb 0.20 - 133 34.68 Oct < 0.1 12 78 Drinking water Nov < 0.1 11 99

T‐Fe mg/L Cl mg/L SO4 mg/L Dec < 0.1 11 76 Standards 5.0 200 250 Jan-2001 < 0.1 < 10.0 86 Dec 0.00 74 143 Feb < 0.1 < 10.0 96 Jan-2000 0.00 169 Mar Feb 0.00 < 10.0 150 Apr < 0.1 < 10.0 94 Mar 0.00 163 140 May < 0.1 < 10.0 89 Apr 0.00 146 119 Jun 0.20 < 10.0 88 May 0.00 134 100 Jul < 0.1 < 10.0 68 Jun 0.00 103 107 Aug < 0.1 < 10.0 86 Jul 0.00 192 175 Sep < 0.1 12 89 Aug 0.40 133 143 Oct < 0.1 11 96 Sep 0.20 175 158 Nov 0.3 < 10.0 92 Oct < 0.1 155 153 Dec < 0.1 15 82 Nov < 0.1 106 160 Jan-2002 0.20 18 105 Dec 0.10 132 148 Feb 0.10 - 82

3-70 T‐Fe [mg/L] Cu [mg/L] Al [mg/L] Mn [mg/L] T‐Fe [mg/L] Cu [mg/L] Al [mg/L] Cl [mg/L] As [mg/L] Zn [mg/L] Cd [mg/L] Mn [mg/L] Cl [mg/L] As [mg/L] SO4 [mg/L] RUIC (%) Zn [mg/L] Cd [mg/L] SO4 [mg/L] RUIC (%)

180,000 60 80,000 45 M-4A

160,000 70,000 40 50 140,000 35 60,000

120,000 40 30 50,000

100,000 25 3-71 30 40,000 (%) (%) mg/L mg/L 80,000 20 M-4B 30,000 60,000 20 15

20,000 40,000 10 10 20,000 10,000 5

0 0 0 0 l l n u n u ul ul ul ul Jan eb Ju J ep Jan eb Ju J ep Jan eb J ep an J ep an J ep an J ep an Dec F Mar Apr May Aug S Oct Nov Dec F Mar Apr May Aug S Oct Nov Dec F Mar May S Nov J Mar May S Nov J Mar May S Nov J Mar May S Nov J

Figure3-11 M-4, M-4A, M-4B Monitoring Point Analysis ('99 Dec～'02 Feb) M-4, M-4A, M-4B Monitoring Point Analysis （'99 Dec～'02Feb） Waste water (precipitation process) *RUIC: Rate of use of installed capacity (14,000 t/m) T‐Fe [mg/L] Cu [mg/L] Al [mg/L] Mn [mg/L] Cl [mg/L] As [mg/L] Zn [mg/L] Cd [mg/L] SO [mg/L] 4 *RUIC (%) Regulation 10.0 3.0 10.0 3.0 2,000 1.0 20.0 0.30 2,000 Dec 29,550 210 3,200 927 < 10.0 27.00 178 0.33 9,750 55.4 Jan-2000 17,240 110 3,400 493 7.18 80 0.33 62,000 22.3 Feb 0.0 Mar 39,290 230 5,600 707 < 10.0 36.00 279 1.00 104,000 31.7 Apr 37,040 200 5,000 552 < 10.0 42.00 183 0.31 116,000 0.0 May 25,340 130 4,350 473 < 10.0 5.50 124 0.24 91,000 36.8 Jun 24,830 210 2,250 349 < 10.0 20.00 124 0.27 82,000 16.4 Jul 14,570 280 2,050 175 < 10.0 < 10.0 91 0.31 46,000 24.9 Aug 18,670 89 2,040 185 < 10.0 1.40 115 0.29 48,000 38.4 Sep 15,100 86 2,160 133 < 10.0 2.50 98 0.30 43,000 35.2 Oct 11,140 72 1,930 285 < 10.0 0.83 71 0.20 32,000 35.7 Nov 16,000 312 3,070 267 < 10.0 4.80 74 0.30 59,000 31.5 Dec 19,590 273 3,190 625 < 10.0 0.76 137 0.31 56,000 28.6 Jan-2001 18,660 339 3,710 319 20 0.16 136 3.60 69,000 Feb 28,620 277 5,360 371 19 0.76 181 0.29 102,000 Mar 25,600 366 5,900 229 15 33.00 109 1.22 95,000 Apr 25,000 442 3,000 633 18 40.00 194 1.39 89,000 May 14,390 242 3,000 404 < 10.0 1.70 148 1.94 45,000 Jun 15,000 317 3,000 710 17 5.20 243 1.85 56,000 Jul 23,470 184 3,448 358 < 10.0 1.40 165 1.62 50,000 Aug 9,800 99 1,000 171 < 10.0 0.02 72 0.96 45,000 Sep 15,400 267 2,000 116 < 10.0 0.54 201 1.38 139,000 Oct 17,110 295 3,000 638 < 10.0 0.01 229 2.14 56,000 Nov 12,150 200 1,000 482 < 10.0 0.05 241 1.84 36,000 Dec 10,700 154 2,000 568 < 10.0 2.40 195 2.18 36,000 Jan-2002 15,000 73 3,000 544 < 10.0 0.04 207 1.50 43,000 Feb 18,000 212 4,000 516 ----29,000

Infiltrate drainageA (evaporation pond)

T‐Fe [mg/L] Cu [mg/L] Al [mg/L] Mn [mg/L] Cl [mg/L] As [mg/L] Zn [mg/L] Cd [mg/L] SO4 [mg/L] *RUIC (%) Mar-2000 4,820 300 360 268 17.0 0.04 85.0 0.43 16,000 31.7 Apr 4,720 340 305 247 22.0 < 0.03 76.0 0.16 13,000 0.0 May 4,510 270 320 213 23.0 < 0.03 65.0 0.31 9,500 36.8 Jun 4,510 380 305 225 15.0 < 0.03 64.0 0.34 13,140 16.4 Jul 4,410 330 314 144 17.0 < 0.03 79.0 0.16 16,340 24.9 Aug 4,510 196 308 141 20.0 < 0.03 50.0 0.33 13,147 38.4 Sep 15,700 132 2,240 124 < 10.0 < 0.03 109.0 0.32 51,000 35.2 Oct 4,340 217 479 173 13.0 < 0.03 83.0 0.32 12,000 35.7 Nov 4,920 233 457 190 17.0 < 0.03 70.0 0.33 21,000 31.5 Dec 15,390 209 1,930 392 < 10.0 0.08 96.0 0.28 54,000 28.6 Jan-2001 3,380 85 136 159 12.0 0.10 44.0 0.19 13,000 Feb 5,130 272 551 230 12.0 0.08 84.0 0.29 22,000 Mar 3,630 85 170 213 24.0 < 0.03 43.0 0.31 16,000 Apr 6,300 203 345 291 26.0 < 0.03 58.0 0.33 22,000 May 3,500 80 156 179 39.0 < 0.005 41.0 0.12 13,000 Jun 4,200 191 406 276 132.0 < 0.005 55.0 0.31 18,000 Jul 5,310 58 135 182 34.0 < 0.005 39.0 0.89 9,400 Aug 3,800 190 392 258 18.0 < 0.005 59.0 0.22 21,000 Sep 2,090 69 142 59 20.0 < 0.005 37.0 0.19 15,000 Oct 5,740 349 786 420 12.0 0.03 231.0 0.39 22,000 Nov 5,810 253 52 310 < 10.0 < 0.005 88.0 0.37 19,000 Dec 5,140 233 560 371 < 10.0 < 0.005 68.0 0.25 20,000 Jan-2002 5,600 230 26 333 37 < 0.005 90 0.32 20,000 Feb 866198425294----18,000

Infiltrate drainageB (evaporation pond)

T‐Fe [mg/L] Cu [mg/L] Al [mg/L] Mn [mg/L] Cl [mg/L] As [mg/L] Zn [mg/L] Cd [mg/L] SO4 [mg/L] *RUIC (%) Mar-2000 0.00 0.00 < 1.0 9.9 75.0 0.08 0.39 < 0.01 990 31.7 Apr 0.00 0.00 1.0 8.4 67.0 < 0,03 0.47 0.02 938 0.0 May 0.00 0.00 24.0 39.0 66.0 < 0,03 6.30 0.03 2,746 36.8 Jun 0.00 0.00 140.0 69.0 35.0 < 0.03 16.00 0.09 3,964 16.4 Jul 0.00 0.00 120.0 50.0 41.0 < 0.03 13.00 0.02 3,912 24.9 Aug 11.00 49.00 68.0 24.0 57.0 < 0.03 3.40 0.05 1,723 38.4 Sep 5.40 688.00 265.0 100.0 14.0 < 0.03 45.00 0.17 7,159 35.2 Oct 18.00 225.00 87.0 48.0 47.0 < 0.03 10.00 0.03 3,078 35.7 Nov 16.00 121.00 46.0 33.0 52.0 < 0.03 6.90 0.15 4,739 31.5 Dec 3,180.00 110.00 165.0 195.0 24.0 < 0.03 51.00 0.02 12,000 28.6 Jan-2001 Feb 29.00 13.00 9.2 20.0 59.0 < 0.03 1.31 0.01 2,779 Mar 16.00 9.30 9.6 18.0 64.0 < 0.03 0.56 < 0.01 2,270 Apr 18.00 7.70 6.0 12.0 70.0 < 0.03 0.61 < 0.01 3,760 May 12.00 34.00 81.0 18.0 43.0 < 0.005 1.70 0.03 2,375 Jun 14.00 8.90 3.0 17.0 43.0 < 0.005 1.00 0.02 1,950 Jul 130.00 290.00 184.0 102.0 25.0 < 0.005 20.00 0.08 4,275 Aug 25.00 401.00 250.0 144.0 16.0 < 0.005 26.00 0.14 7,050 Sep 7.30 1,200.00 652.0 75.0 < 10.0 < 0.005 68.00 0.41 4,100 Oct 138.00 350.00 151.0 161.0 26.0 < 0.005 94.00 0.10 7,600 Nov 450.00 156.00 66.0 81.0 33.0 < 0.005 7.30 0.10 6,000 Dec 360.00 71.00 46.0 83.0 40.0 < 0.005 6.40 0.02 5,600 Jan-2002 188.0 35.00 24.0 72.0 64.0 < 0.005 4 0.02 5,100 Feb 982.0 0.84 7.0 79.0 ----6,300

3-72 L/sec

250 200 150 100 50 0

M-7 b e

F ）

ct O

Q [ L/sec]

'02Feb ug A

～ un

e F

'99 Dec

ec （

an J

SO4 [mg/L]

ar M

M-6

Mn [mg/L] an

ay M

Al [mg/L] ar

ec D

Cu [mg/L] ct

Figure 3-12 M-5, M-6, M-7 Monitoring Point Analysis A

5 b e F

Fe [mg/L]

M-

‐ ec

T D

ec D 0

7000 6000 5000 4000 3000 2000 1000 mg/L

3-73 M-5, M-6, M-7 Monitoring Point Analysis （'99 Dec～'02Feb） Ingenio river ( 500 m down from the plant) *Standards : For Irrigation Water - T‐Fe [mg/L] Cu [mg/L] Al [mg/L] Mn [mg/L] Cl [mg/L] As [mg/L] Hg [mg/L] Zn [mg/L] Mo [mg/L] Cd [mg/L] SO4 [mg/L] Q [ L/sec] Standards 5.0 0.2 5.0 0.2 200 0.1 0.001 2.0 0.01 0.01 250 Dec 720.0 24.0 35.0 70.0 < 0.03 < 0.001 6.7 < 0.01 0.06 2,309.0 54.29 Jan-2000 510.0 11.0 25.0 < 0.03 < 0.001 4.5 < 0.01 0.02 1,773.0 55.23 Feb 620.0 33.0 29.0 < 10.0 < 0.03 < 0.001 6.7 0.04 0.04 2,116.0 71.58 Mar 620.0 160.0 35.0 28.0 138.0 < 0.03 < 0.001 6.9 < 0.01 0.05 1,872.0 85.14 Apr 410.0 120.0 10.0 15.0 101.0 < 0.03 < 0.001 4.2 < 0.01 0.02 988.0 87.78 May 620.0 80.0 13.0 19.0 101.0 < 0.03 < 0.001 4.7 < 0.01 0.04 1,263.0 136.70 Jun 410.0 80.0 25.0 19.0 109.0 < 0.03 < 0.001 4.1 < 0.01 0.02 1,236.0 212.62 Jul 310.0 100.0 1.7 8.3 105.0 < 0.03 < 0.001 1.8 < 0.01 0.02 619.0 112.38 Aug 310.0 17.0 6.1 13.0 96.0 < 0.03 < 0.001 3.4 < 0.01 0.01 1,031.0 99.18 Sep 720.0 39.0 30.0 22.0 71.0 < 0.03 < 0.001 3.6 < 0.01 < 0.01 2,234.0 127.69 Oct 820.0 38.0 45.0 34.0 78.0 < 0.03 < 0.001 8.2 < 0.01 0.01 2,803.0 68.80 Nov 516.0 46.0 62.0 42.0 73.0 < 0.03 < 0.001 11.0 < 0.01 0.03 3,676.0 59.83 Dec 281.0 53.0 58.0 41.0 78.0 < 0.03 < 0.001 7.9 < 0.01 0.04 2,458.0 72.09 Jan-2001 291.0 35.0 48.0 38.0 49.0 < 0.03 < 0.001 8.8 < 0.01 0.03 3,351.0 75.50 Feb 291.0 45.0 60.0 34.0 65.0 < 0.03 < 0.001 10.0 < 0.01 0.04 3,319.0 76.45 Mar 305.0 40.0 63.0 42.0 62.0 < 0.03 < 0.001 8.8 < 0.01 0.06 3,190.0 81.61 Apr 274.0 35.0 50.0 26.0 60.0 < 0.03 < 0.001 7.9 < 0.01 0.06 3,348.0 103.00 May 770.0 29.0 219.0 25.0 61.0 < 0.005 < 0.001 8.7 < 0.01 0.06 2,775.0 106.36 Jun 33.0 15.0 23.0 17.0 61.0 < 0.005 < 0.001 3.6 < 0.01 0.04 1,400.0 94.96 Jul 240.0 18.0 47.0 24.0 58.0 < 0.005 < 0.001 5.0 < 0.01 0.03 1,250.0 140.62 Aug 78.0 17.0 26.0 22.0 55.0 < 0.005 < 0.001 5.5 < 0.01 < 0.01 1,975.0 128.81 Sep 106.0 22.0 37.0 12.0 67.0 < 0.005 < 0.001 5.2 0.12 < 0.01 2,275.0 73.32 Oct 222.0 31.0 70.0 8.9 65.0 < 0.005 < 0.001 8.9 < 0.01 < 0.01 2,988.0 74.59 Nov 458.0 50.0 78.0 62.0 49.0 < 0.005 < 0.001 12.0 < 0.01 0.06 3,740.0 74.17 Dec 821.0 57.0 98.0 70.0 41.0 < 0.005 < 0.001 13.0 0.12 < 0.01 3,700.0 74.19 Jan-2002 677.0 46.0 82.0 80.0 72.0 < 0.005 < 0.001 12.0 < 0.01 0.05 4,100.0 83.39 Feb 956.0 68.0 104.0 99.0 4,800.0 133.57 Ingenio river ( 2 km down from the plant) - T‐Fe [mg/L] Cu [mg/L] Al [mg/L] Mn [mg/L] Cl [mg/L] As [mg/L] Hg [mg/L] Zn [mg/L] Mo [mg/L] Cd [mg/L] SO4 [mg/L] Standards 5.0 0.2 5.0 0.2 200 0.1 0.001 2.0 0.01 0.01 250 Dec 362.7 24.4 11.0 28.0 66.00 < 0.03 < 0.001 5.60 < 0.01 0.03 1,842.0 Jan-2000 251.3 16.9 29.0 23.0 < 0.03 < 0.001 3.50 < 0.01 0.04 2,094.0 Feb 286.0 19.4 15.0 15.0 < 10.0 < 0.03 < 0.001 4.30 < 0.01 0.02 1,429.0 Mar 292.0 20.6 33.0 24.0 138.00 < 0.03 < 0.001 6.20 < 0.01 0.05 1,723.0 Apr 225.4 15.4 13.0 15.0 103.00 < 0.03 < 0.001 2.40 < 0.01 0.02 1,263.0 May 210.5 13.0 7.5 16.0 119.00 < 0.03 < 0.001 3.80 < 0.01 0.02 1,062.0 Jun 156.1 9.6 < 1.0 11.0 114.00 < 0.03 < 0.001 2.10 < 0.01 < 0.01 713.0 Jul 37.8 0.7 2.5 8.5 100.00 < 0.03 < 0.001 1.80 < 0.01 0.02 681.0 Aug 0.7 2.9 < 1.0 8.3 111.00 < 0.03 < 0.001 0.84 < 0.01 < 0.01 657.0 Sep 11.0 9.1 7.2 12.0 98.00 < 0.03 < 0.001 2.80 < 0.01 < 0.01 924.0 Oct 37.0 8.6 4.8 16.0 111.00 < 0.03 < 0.001 2.70 < 0.01 < 0.01 813.0 Nov 66.0 15.0 17.0 19.0 100.00 < 0.03 < 0.001 4.60 < 0.01 0.01 1,687.0 Dec 70.0 18.0 35.0 14.0 76.00 < 0.03 < 0.001 4.90 < 0.01 0.03 1,605.0 Jan-2001 92.0 17.0 16.0 22.0 65.00 < 0.03 < 0.001 5.10 < 0.01 < 0.01 1,881.0 Feb 106.0 28.0 45.0 25.0 84.00 < 0.03 < 0.001 7.10 < 0.01 0.02 3,147.0 Mar 40.0 17.0 25.0 17.0 73.00 < 0.03 < 0.001 4.00 < 0.01 < 0.01 1,820.0 Apr 24.0 35.0 15.0 8.1 67.00 < 0.03 < 0.001 2.90 < 0.01 0.03 1,353.0 May 19.0 11.0 91.0 8.5 71.00 < 0.005 < 0.001 2.20 < 0.01 0.03 975.0 Jun 0.6 6.9 10.0 9.7 63.00 < 0.005 < 0.001 2.50 < 0.01 0.03 863.0 Jul 107.0 8.0 28.0 10.0 62.00 < 0.005 < 0.001 1.60 < 0.01 0.02 675.0 Aug 0.3 5.8 7.0 6.8 85.00 < 0.005 < 0.001 2.20 < 0.01 < 0.01 875.0 Sep < 0.1 5.8 4.0 7.6 83.00 < 0.005 < 0.001 1.80 < 0.01 < 0.01 788.0 Oct 33.0 15.0 35.0 4.9 73.00 < 0.005 < 0.001 4.90 < 0.01 < 0.01 1,600.0 Nov 31.0 15.0 27.0 16.0 67.00 < 0.005 < 0.001 4.00 < 0.01 0.01 1,488.0 Dec 27.0 12.0 23.0 20.0 57.00 < 0.005 < 0.001 3.60 < 0.01 < 0.01 1,225.0 Jan-2002 136.0 19.0 24.0 37.0 82.00 < 0.005 < 0.001 7.20 < 0.01 < 0.01 2,050.0 Feb 36.0 10.0 12.0 20.0 1,359.0 Ingenio river ( 5 km down from the plant) - T‐Fe [mg/L] Cu [mg/L] Al [mg/L] Mn [mg/L] Cl [mg/L] As [mg/L] Hg [mg/L] Zn [mg/L] Mo [mg/L] Cd [mg/L] SO4 [mg/L] Standards 5.0 0.2 5.0 0.2 200 0.1 0.001 2.0 0.01 0.01 250 Dec 0.05 0.05 1.00 0.50 144.0 < 0.03 < 0.001 < 0.05 < 0.01 < 0.01 793.0 Jan-2000 0.05 0.05 1.00 0.40 < 0.03 < 0.001 0.09 < 0.01 < 0.01 979.0 Feb 0.05 0.05 0.05 0.45 < 10.0 < 0.03 < 0.001 0.35 < 0.01 < 0.01 967.0 Mar 0.05 0.05 0.05 0.71 312.0 < 0.03 < 0.001 0.35 < 0.01 < 0.01 800.0 Apr 0.05 0.05 0.05 2.30 231.0 < 0.03 < 0.001 0.57 < 0.01 < 0.01 788.0 May 0.05 0.05 1.00 2.50 220.0 < 0.03 < 0.001 0.66 < 0.01 < 0.01 663.0 Jun 0.13 0.05 1.00 2.10 190.0 < 0.03 < 0.001 0.23 < 0.01 < 0.01 646.0 Jul 0.11 0.05 1.00 0.55 179.0 < 0.03 < 0.001 0.10 < 0.01 < 0.01 619.0 Aug 0.20 < 0.05 1.00 0.10 189.0 < 0.03 < 0.001 < 0.05 < 0.01 < 0.01 612.0 Sep 0.30 < 0.05 1.00 0.30 179.0 < 0.03 < 0.001 0.06 < 0.01 < 0.01 620.0 Oct < 0.1 < 0.05 1.00 0.20 202.0 < 0.03 < 0.001 < 0.05 < 0.01 < 0.01 609.0 Nov < 0.1 < 0.05 < 1.0 0.10 190.0 < 0.03 < 0.001 < 0.05 < 0.01 < 0.01 747.0 Dec 0.20 < 0.05 1.00 0.10 173.0 < 0.03 < 0.001 0.06 < 0.01 < 0.01 729.0 Jan-2001 0.30 < 0.05 1.00 < 0.05 182.0 < 0.03 < 0.001 0.09 < 0.01 < 0.01 883.0 Feb 0.20 < 0.05 1.00 0.36 181.0 < 0.03 < 0.001 0.36 < 0.01 < 0.01 1,008.0 Mar 0.10 0.11 1.00 1.50 140.0 < 0.03 < 0.001 0.63 < 0.01 < 0.01 1,250.0 Apr 0.10 0.16 1.00 1.70 150.0 < 0.03 < 0.001 0.45 < 0.01 < 0.01 1,012.0 May 0.20 0.17 < 1.0 1.30 143.0 < 0.005 < 0.001 0.81 < 0.01 < 0.01 838.0 Jun 0.20 0.06 < 1.0 3.30 118.0 < 0.005 < 0.001 0.36 < 0.01 < 0.01 725.0 Jul < 0.1 < 0.05 1.00 3.20 127.0 < 0.005 < 0.001 0.16 < 0.01 < 0.01 662.0 Aug 0.30 < 0.05 < 1.0 < 0.05 134.0 < 0.005 < 0.001 0.23 < 0.01 < 0.01 712.0 Sep < 0.1 0.05 < 1.0 0.07 159.0 < 0.005 < 0.001 1.30 < 0.01 < 0.01 838.0 Oct < 0.1 0.05 < 1.0 1.20 150.0 < 0.005 < 0.001 0.48 < 0.01 < 0.01 900.0 Nov 0.10 0.12 < 1.0 1.60 164.0 < 0.005 < 0.001 0.55 < 0.01 < 0.01 800.0 Dec 0.10 0.35 < 1.0 5.40 172.0 < 0.005 < 0.001 1.10 < 0.01 < 0.01 925.0 Jan-2002 0.10 0.38 < 1.0 6.00 200.0 < 0.005 < 0.001 0.98 < 0.01 < 0.01 1,000.0 Feb < 0.1 0.67 < 1.0 7.40 912.0

3-74 T‐Fe [mg/s] Cl [mg/s] SO4 [mg/s] 800,000

700,000 M-5

600,000

500,000

400,000 mg/s

300,000

200,000 M-1 100,000

b b b r y p r y p un un an a a Jul an a a Jul an Dec Fe Apr J Aug Oct Dec Fe Apr J Aug Oct Dec Fe J M M Se Nov J M M Se Nov J

Figure3-13 M-1・M-5 Flux Volume of T-Fe, Cl, SO4 ('99 Dec～'02 Feb)

T‐Fe [mg/s] Cl [mg/s] SO4 [mg/s] T‐Fe [mg/s] Cl [mg/s] SO4 [mg/s] Dec 0.68 527 2,093 Dec 39,089 3,800 125,356 Jan-2000 2.91 1,593 Jan-2000 28,167 97,923 Feb 0.89 2,200 Feb 44,380 151,463 Mar 2.73 2,045 3,271 Mar 52,787 11,749 159,382 Apr 1.34 1,882 2,528 Apr 35,990 8,866 86,727 May 8.18 2,775 4,092 May 84,754 13,807 172,652 Jun 28.79 9,684 12,564 Jun 87,174 23,176 262,798 Jul 18.32 5,121 6,847 Jul 34,838 11,800 69,563 Aug < 4.79 3,067 5,846 Aug 30,746 9,521 102,255 Sep < 5.78 4,107 6,594 Sep 91,937 9,066 285,259 Oct < 1.38 978 1,640 Oct 56,416 5,366 192,846 Nov < 0.75 468 1,125 Nov 30,872 4,368 219,935 Dec < 0.60 419 802 Dec 20,257 5,623 177,197 Jan-2001 < 1.34 658 2,164 Jan-2001 21,971 3,700 253,000 Feb < 1.78 1,012 2,948 Feb 22,247 4,969 253,738 Mar < 1.60 931 2,504 Mar 24,891 5,060 260,336 Apr < 1.70 1,035 2,359 Apr 28,222 6,180 344,844 May < 2.29 1,098 3,090 May 81,897 6,488 295,149 Jun < 3.78 1,551 4,427 Jun 3,134 5,793 132,944 Jul < 8.38 4,358 12,235 Jul 33,749 8,156 175,775 Aug < 6.16 2,712 7,149 Aug 10,047 7,085 254,400 Sep < 2.53 1,340 3,212 Sep 7,772 4,912 166,803 Oct < 1.45 883 1,867 Oct 16,559 4,848 222,875 Nov < 1.25 748 1,258 Nov 33,970 3,634 277,396 Dec < 1.17 796 1,171 Dec 60,910 3,042 274,503 Jan-2001 < 1.04 676 1,477 Jan-2002 56,455 6,004 341,899 Feb 6.94 4,612 Feb 127,693 0 641,136

3-75 Table3-29 Monitoring Point Analysis December '99 ELEMENT M - 1 M - 2 M - 3 M - 4 M - 5 M - 6 M - 7 STANDARD

Q [lts/seg] 13.50 - - - 54.29 54.04 48.96 - pH 6.90 7.00 7.20 3.80 4.54 4.60 6.68 6,0 - 8,5 t° [°C] 21.6 21.6 20.1 25.7 19.0 18.7 16.6 < 40,0 Fe Total [mg/L] 0.05 nd nd 29,550.0 720.0 362.7 0.05 10.0 Fe +2 [mg/L] - - - 29,230.0 620.0 410.0 - - Cu [mg/L] 0.05 nd nd 210.0 nd 24.41 0.05 3.0 Al [mg/L] < 1.0 < 1.0 < 1.0 3,200.00 24.0 11.0 < 1,0 10.0 Mn [mg/L] < 0.05 < 0.05 < 0.05 927.00 35.00 28.00 0.50 3.0 Cl [mg/L] 39.00 74.00 44.00 < 10.0 70.00 66.00 144.00 2,000.0 As [mg/L] < 0.03 < 0.03 < 0.03 27.00 < 0.03 < 0.03 < 0.03 1.00 Hg [mg/L] < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 0.01 Zn [mg/L] < 0.05 < 0.05 < 0.05 178.00 6.70 5.60 < 0.05 20.00 Mo [mg/L] < 0.01 < 0.01 < 0.01 0.05 < 0.01 < 0.01 < 0.01 2.50 Cd [mg/L] < 0.01 < 0.01 < 0.01 0.33 0.06 0.03 < 0.01 0.30 SO4 [mg/L] 155.0 143.0 117.0 9,750.0 2,309.0 1,842.0 793.0 2,000.0 Cond. [µS/cm] 1,610.0 1,590.0 1,220.0 7,620.0 5,420.0 5,230.0 3,400.0 -

Table3-30 Monitoring Point Analysis January '00 ELEMENT M - 1 M - 2 M - 3 M - 4 M - 5 M - 6 M - 7 STANDARD

Q [lts/seg] 10.41 - - - 55.23 60.10 50.28 - pH 6.86 6.75 7.00 3.51 4.58 4.66 6.75 6,0 - 8,5 t° [°C] 17.5 20.8 18.7 27.1 18.8 18.5 16.4 < 40,0 Fe Total [mg/L] 0.28 nd nd 17,240.0 510.0 251.3 0.05 10.0 Fe +2 [mg/L] nd nd nd 17,030.0 360.0 nd nd - Cu [mg/L] 0.05 nd nd 110.0 nd 16.90 0.05 3.0 Al [mg/L] < 1.0 < 1.0 < 1.0 3,400.0 11.0 29.0 < 1.0 10.0 Mn [mg/L] < 0.05 0.06 0.06 493.0 25.0 23.0 0.40 3.0 Cl [mg/L] 2,000.0 As [mg/L] < 0.03 < 0.03 < 0.03 7.18 < 0.03 < 0.03 < 0.03 1.00 Hg [mg/L] < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 0.01 Zn [mg/L] < 0.05 < 0.05 < 0.05 80.0 4.5 3.5 0.09 20.00 Mo [mg/L] < 0.01 < 0.01 0.04 0.37 < 0.01 < 0.01 < 0.01 2.50 Cd [mg/L] < 0.01 < 0.01 < 0.01 0.33 0.02 0.04 < 0.01 0.30 SO4 [mg/L] 153.0 169.0 180.0 62,000.0 1,773.0 2,094.0 979.0 2,000.0 Cond. [µS/cm] 1,410.0 1,670.0 780.0 55,300.0 4,580.0 4,210.0 3,450.0 -

Table3-31 Monitoring Point Analysis February '00 ELEMENT M - 1 M - 2 M - 3 * M - 4 * M - 5 M - 6 M - 7 STANDARD

Q [lts/seg] 17.74 - - - 71.58 85.74 77.15 - pH 6.74 6.62 - - 4.50 4.53 6.60 6,0 - 8,5 t° [°C] 18.2 22.5 - - 19.2 18.8 16.7 < 40,0 Fe Total [mg/L] 0.05 nd - - 620.0 286.0 0.05 10.0 Fe +2 [mg/L] nd nd - - 510.0 nd nd - Cu [mg/L] 0.05 nd - - nd 19.4 0.05 3.0 Al [mg/L] < 1.0 < 1.0 - - 33.0 15.0 < 1.0 10.0 Mn [mg/L] < 0.05 0.05 - - 29.0 15.0 0.45 3.0 Cl [mg/L] < 10.0 < 10.0 - - < 10.0 < 10.0 < 10.0 2,000.0 As [mg/L] < 0.03 < 0.03 - - < 0.03 < 0.03 < 0.03 1.00 Hg [mg/L] < 0.001 < 0.001 - - < 0.001 < 0.001 < 0.001 0.01 Zn [mg/L] < 0.05 0.23 - - 6.7 4.3 0.35 20.00 Mo [mg/L] < 0.01 < 0.01 - - 0.04 < 0.01 < 0.01 2.50 Cd [mg/L] < 0.01 < 0.01 - - 0.04 0.02 < 0.01 0.30 SO4 [mg/L] 124.0 150.0 - - 2,116.0 1,429.0 967.0 2,000.0 Cond. [µS/cm] 1,330.0 1,660.0 - - 5,050.0 4,320.0 3,790.0 -

The Location of Monitoring Point: nd : not determined M-1:The Ingenio river (the upper stream of the plant) M-2: Spring Water for Drinking. M-3: Industrial water(Talhuen water) M-4: Waste water from precipitation process. M-5: The Ingenio River(500 m down stream of the plant) M-6: The Ingenio River ( 2 Km down stream of the plant) M-7: The Ingenio River ( 5 Km down stream of the plant) STANDARD : The reguration for discharge of effluent to subjects which have capacity of natural purification. ( February '00 ) *M-3: Industrial water (Talhuen water) *(cleaning the watertank) *M-4: Waste water from precipitation process *(the operation suspended)

3-76 Table3-32 Monitoring Point Analysis March '00 ELEMENT M - 1 M - 2 M - 3 M - 4 M - 4A M - 4B M - 5 M - 6 M - 7 STANDARD

Q [lts/seg] 27.26 ----- 85.14 115.25 98.85 - pH 7.12 7.19 7.49 3.59 - - 4.84 4.68 6.81 6,0 - 8,5 t° [°C] 17.5 21.3 20.2 29.5 - - 18.5 18.9 16.1 < 40,0 Fe Total [mg/L] 0.10 nd nd 39,290.0 4,820.0 nd 620.0 292.0 0.05 10.0 Fe +2 [mg/L] nd nd nd 38,570.0 4,620.0 nd 510.0 nd nd - Cu [mg/L] 0.05 nd nd 230.0 300.0 nd 160.0 20.6 0.05 3.0 Al [mg/L] < 1.0 < 1.0 < 1.0 5,600.0 360.0 < 1.0 35.0 33.0 < 1.0 10.0 Mn [mg/L] < 0.05 < 0.05 < 0.05 707.0 268.0 9.9 28.0 24.0 0.71 3.0 Cl [mg/L] 75.0 163.0 10.0 < 10.0 17.0 75.0 138.0 138.0 312.0 2,000.0 As [mg/L] 0.10 < 0.03 < 0.03 36.0 0.04 0.08 < 0.03 < 0.03 < 0.03 1.00 Hg [mg/L] < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 0.01 Zn [mg/L] < 0.05 < 0.05 0.08 279.0 85.0 0.39 6.9 6.2 0.35 20.00 Mo [mg/L] < 0.01 < 0.01 < 0.01 2.80 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 2.50 Cd [mg/L] < 0.01 < 0.01 < 0.01 1.00 0.43 < 0.01 0.05 0.05 < 0.01 0.30 SO4 [mg/L] 120.0 140.0 78.0 104,000.0 16,000.0 990.0 1,872.0 1,723.0 800.0 2,000.0 Cond. [µS/cm] 1,330.0 1,710.0 550.0 79,500.0 18,300.0 2,900.0 4,220.0 3,990.0 3,280.0 -

Table3-33 Monitoring Point Analysis April '00 ELEMENT M - 1 M - 2 M - 3 M - 4 M - 4A M - 4B M - 5 M - 6 M - 7 STANDARD

Q [lts/seg] 26.89 ----- 87.78 122.31 156.41 - pH 7.42 7.16 7.65 3.60 3.86 3.49 5.33 4.59 6.56 6,0 - 8,5 t° [°C] 16.7 20.5 18.7 25.0 18.4 15.4 16.4 17.3 15.1 < 40,0 Fe Total [mg/L] 0.05 nd nd 37,040.0 4,720.0 nd 410.0 225.4 0.05 10.0 Fe +2 [mg/L] nd nd nd 36,520.0 4,620.0 nd 310.0 nd nd - Cu [mg/L] 0.05 nd nd 200.0 340.0 nd 120.0 15.4 0.05 3.0 Al [mg/L] < 1.0 < 1.0 < 1.0 5,000.0 305.0 1.0 10.0 13.0 < 1.0 10.0 Mn [mg/L] < 0.05 0.10 < 0.05 552.0 247.0 8.4 15.0 15.0 2.3 3.0 Cl [mg/L] 70.0 146.0 12.0 < 10.0 22.0 67.0 101.0 103.0 231.0 2,000.0 As [mg/L] < 0.03 < 0.03 < 0.03 42.0 < 0.03 < 0.03 < 0.03 < 0.03 < 0.03 1.00 Hg [mg/L] < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 0.01 Zn [mg/L] 0.22 0.14 0.15 183.0 76.0 0.47 4.2 2.4 0.57 20.00 Mo [mg/L] < 0.01 < 0.01 < 0.01 1.10 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 2.50 Cd [mg/L] < 0.01 < 0.01 < 0.01 0.31 0.16 0.02 0.02 0.02 < 0.01 0.30 SO4 [mg/L] 94.0 119.0 71.0 116,000.0 13,000.0 938.0 988.0 1,263.0 788.0 2,000.0 Cond. [µS/cm] 1,030.0 1,440.0 510.0 46,600.0 13,900.0 2,430.0 2,540.0 2,940.0 2,680.0 -

Table3-34 Monitoring Point Analysis May '00 ELEMENT M - 1 M - 2 M - 3 M - 4 M - 4A M - 4B M - 5 M - 6 M - 7 STANDARD

Q [lts/seg] 35.58 -----136.70 123.22 164.98 - pH 7.17 7.18 7.58 3.55 3.79 3.78 5.52 5.36 6.99 6,0 - 8,5 t° [°C] 13.9 17.0 15.2 23.9 17.3 14.8 15.0 14.8 12.5 < 40,0 Fe Total [mg/L] 0.23 nd nd 25,340.0 4,510.0 nd 620.0 210.5 0.05 10.0 Fe +2 [mg/L] nd nd nd 25,130.0 4,310.0 nd 510.0 nd nd - Cu [mg/L] 0.05 nd nd 130.0 270.0 nd 80.0 13.0 0.05 3.0 Al [mg/L] < 1.0 < 1.0 < 1.0 4,350.0 320.0 24.0 13.0 7.5 < 1.0 10.0 Mn [mg/L] < 0.05 < 0.05 0.06 473.0 213.0 39.0 19.0 16.0 2.5 3.0 Cl [mg/L] 78.0 134.0 15.0 < 10.0 23.0 66.0 101.0 119.0 220.00 2,000.0 As [mg/L] < 0.03 < 0.03 < 0.03 5.5 < 0.03 < 0.03 < 0.03 < 0.03 < 0.03 1.00 Hg [mg/L] < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 0.01 Zn [mg/L] 0.40 0.65 0.21 124.0 65.0 6.3 4.7 3.8 0.66 20.00 Mo [mg/L] < 0.01 < 0.01 < 0.01 1.00 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 2.50 Cd [mg/L] < 0.01 < 0.01 < 0.01 0.24 0.31 0.03 0.04 0.02 < 0.01 0.30 SO4 [mg/L] 115.0 100.0 92.0 91,000.0 9,500.0 2,746.0 1,263.0 1,062.0 663.0 2,000.0 Cond. [µS/cm] 906.0 1,152.0 484.0 35,687.0 13,106.0 3,922.0 2,533.0 2,170.0 2,329.0 -

nd : not determined. M-1: The Ingenio river (the upper stream of the plant). M-2: Spring water for drinking. M-3: Industrial water (Talhuen water). M-4: Waste water from precipitation process. M-4A: Infiltrate drainage at downstream of evaporation pond. M-4B: Infiltrate drainage at upstream of evaporation pond. M-5: The Ingenio river (500 m down stream of the plant). M-6: The Ingenio river (2 Km down stream of the plant). M-7:The Ingenio river (5 Km down stream of the plant). STANDARD : The reguration for discharge of effluent to subjects which have capacity of natural purification.

3-77 Table3-35 Monitoring Point Analysis June '00 ELEMENT M - 1 M - 2 M - 3 * M - 4 M - 4A M - 4B M - 5 M - 6 M - 7 STANDARD

Q [lts/seg] 130.87 -----212.62 250.70 608.65 - pH 7.16 7.25 - 3.35 3.92 3.72 5.27 5.54 6.73 6,0 - 8,5 t° [°C] 15.3 15.9 - 24.8 18.4 15.8 16.3 17.1 13.0 < 40,0 Fe Total [mg/L] 0.22 nd - 24,830.0 4,510.0 nd 410.0 156.1 0.13 10.0 Fe +2 [mg/L] nd nd - 24,720.0 4,410.0 nd 310.0 10.0 nd - Cu [mg/L] 0.05 nd - 210.0 380.0 nd 80.0 9.6 0.05 3.0 Al [mg/L] < 1.0 < 1.0 - 2,250.0 305.0 140.0 25.0 < 1.0 < 1.0 10.0 Mn [mg/L] < 0.05 < 0.05 - 349.0 225.0 69.0 19.0 11.0 2.1 3.0 Cl [mg/L] 74.0 103.0 - < 10.0 15.0 35.0 109.0 114.0 190.0 2,000.0 As [mg/L] < 0.03 < 0.03 - 20.00 < 0.03 < 0.03 < 0.03 < 0.03 < 0.03 1.00 Hg [mg/L] < 0.001 < 0.001 - < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 0.01 Zn [mg/L] < 0.05 < 0.05 - 124.00 64.00 16.00 4.10 2.10 0.23 20.00 Mo [mg/L] 0.01 < 0.01 - 1.30 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 2.50 Cd [mg/L] < 0.01 < 0.01 - 0.27 0.34 0.09 0.02 < 0.01 < 0.01 0.30 SO4 [mg/L] 96.0 107.0 - 82,000.0 13,140.0 3,964.0 1,236.0 713.0 646.0 2,000.0 Cond. [µS/cm] 1,020.0 1,160.0 - 57,800.0 14,800.0 5,380.0 2,820.0 1,800.0 2,420.0 -

Table3-36 Monitoring Point Analysis July '00 ELEMENT M - 1 M - 2 M - 3 * M - 4 M - 4A M - 4B M - 5 M - 6 M - 7 STANDARD

Q [lts/seg] 53.91 -----112.38 135.80 156.63 - pH 7.07 6.93 - 2.72 3.94 3.48 5.90 5.87 7.07 6,0 - 8,5 t° [°C] 15.6 16.0 - 20.7 19.4 18.5 16.2 17.8 12.9 < 40,0 Fe Total [mg/L] 0.34 nd - 14,570.0 4,410.0 nd 310.0 37.76 0.11 10.0 Fe +2 [mg/L] nd nd - 14,160.0 4,210.0 nd 100.0 nd nd - Cu [mg/L] 0.05 nd - 280.0 330.0 nd 100.0 0.69 0.05 3.0 Al [mg/L] < 1.0 < 1.0 - 2,050.0 314.0 120.0 1.7 2.5 < 1,0 10.0 Mn [mg/L] < 0.05 < 0.05 - 175.0 144.0 50.0 8.3 8.5 0.55 3.0 Cl [mg/L] 95.0 192.0 - < 10,0 17.0 41.0 105.0 100.0 179.0 2,000.0 As [mg/L] < 0.03 < 0.03 - 1.00 < 0.03 < 0.03 < 0.03 < 0.03 < 0.03 1.00 Hg [mg/L] < 0.001 < 0.001 - < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 0.01 Zn [mg/L] < 0.05 < 0.05 - 91.0 79.0 13.0 1.8 1.8 0.10 20.00 Mo [mg/L] < 0.01 < 0.01 - 0.50 0.09 < 0.01 < 0.01 < 0.01 < 0.01 2.50 Cd [mg/L] < 0.01 < 0.01 - 0.31 0.16 0.02 0.02 0.02 < 0.01 0.30 SO4 [mg/L] 127.0 175.0 - 46,000.0 16,340.0 3,912.0 619.0 681.0 619.0 2,000.0 Cond. [µS/cm] 1,080.0 1,520.0 - 41,200.0 15,700.0 5,580.0 1,840.0 1,800.0 2,320.0 -

Table3-37 Monitoring Point Analysis August '00 ELEMENT M - 1 M - 2 M - 3 M - 4 M - 4A M - 4B M - 5 M - 6 M - 7 STANDARD

Q [lts/seg] 47.92 ----- 99.18 117.83 128.94 - pH 7.61 7.40 7.72 4.03 4.14 3.99 5.44 5.65 7.00 6,0 - 8,5 t° [°C] 16.7 20.5 18.7 25.0 18.4 15.4 16.4 17.3 15.1 < 40,0 Fe Total [mg/L] < 0.1 0.4 0.1 18,670.0 4,510.0 11.0 310.0 0.7 0.2 10.0 Fe +2 [mg/L] nd nd nd 18,570.0 2,560.0 nd 210.0 nd nd - Cu [mg/L] < 0.05 < 0.05 < 0.05 89.0 196.0 49.0 17.0 2.9 < 0.05 3.0 Al [mg/L] < 1.0 < 1.0 < 1.0 2,040.0 308.0 68.0 6.1 < 1.0 < 1.0 10.0 Mn [mg/L] < 0.05 < 0.05 < 0.05 185.0 141.0 24.0 13.0 8.3 0.10 3.0 Cl [mg/L] 64.0 133.0 12.0 < 10.0 20.0 57.0 96.0 111.0 189.0 2,000.0 As [mg/L] < 0.03 < 0.03 < 0.03 1.40 < 0.03 < 0.03 < 0.03 < 0.03 < 0.03 1.00 Hg [mg/L] < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 0.01 Zn [mg/L] < 0.05 < 0.05 0.13 115.0 50.0 3.4 3.4 0.84 < 0.05 20.00 Mo [mg/L] < 0.01 < 0.01 < 0.01 0.45 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 2.50 Cd [mg/L] < 0.01 < 0.01 < 0.01 0.29 0.33 0.05 0.01 < 0.01 < 0.01 0.30 SO4 [mg/L] 122.0 143.0 84.0 48,000.0 13,147.0 1,723.0 1,031.0 657.0 612.0 2,000.0 Cond. [µS/cm] 914.0 1,100.0 430.0 40,100.0 12,400.0 3,170.0 1,980.0 1,470.0 2,110.0 -

nd : not determined. M-1: The Ingenio river (the upper stream of the plant). M-2: Spring water for drinking. M-3: Industrial water (Talhuen water). M-4: Waste water from precipitation process. M-4A: Infiltrate drainage at downstream of evaporation pond. M-4B: Infiltrate drainage at upstream of evaporation pond. M-5: The Ingenio river (500 m down stream of the plant). M-6: The Ingenio river (2 Km down stream of the plant). M-7: The Ingenio river (5 Km down stream of the plant). STANDARD : The reguration for discharge of effluent to subjects which have capacity of natural purification.

3-78 Table3-38 Monitoring Point Analysis September '00 ELEMENT M - 1 M - 2 M - 3 * M - 4 M - 4A M - 4B M - 5 M - 6 M - 7 STANDARD

Q [lts/seg] 57.84 -----127.69 147.51 165.28 - pH 7.54 7.36 - 3.52 2.57 3.40 5.55 5.13 7.02 6,0 - 8,5 t° [°C] 19.9 19.3 - 20.8 20.2 22.7 21.3 25.1 15.7 < 40,0 Fe Total [mg/L] < 0.1 0.20 - 15,100.0 15,700.0 5.4 720.0 11.0 0.3 10.0 Fe +2 [mg/L] nd nd - 14,000.0 14,800.0 nd 620.0 nd nd - Cu [mg/L] < 0.05 < 0.05 - 86.0 132.0 688.0 39.0 9.1 < 0.05 3.0 Al [mg/L] < 1.0 < 1.0 - 2,160.0 2,240.0 265.0 30.0 7.2 < 1.0 10.0 Mn [mg/L] < 0.05 < 0,05 - 133.0 124.0 100.0 22.0 12.0 0.30 3.0 Cl [mg/L] 71.0 175.0 - < 10.0 < 10.0 14.0 71.0 98.0 179.0 2,000.0 As [mg/L] < 0.03 < 0.03 - 2.50 < 0.03 < 0.03 < 0.03 < 0.03 < 0.03 1.00 Hg [mg/L] < 0.001 < 0.001 - < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 0.01 Zn [mg/L] < 0.05 0.07 - 98.00 109.00 45.00 3.60 2.80 0.06 20.00 Mo [mg/L] < 0.01 < 0.01 - 0.29 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 2.50 Cd [mg/L] < 0.01 < 0.01 - 0.30 0.32 0.17 < 0.01 < 0.01 < 0.01 0.30 SO4 [mg/L] 114.0 158.0 - 43,000.0 51,000.0 7,159.0 2,234.0 924.0 620.0 2,000.0 Cond. [µS/cm] 1,050.0 1,690.0 - 39,100.0 42,700.0 7,890.0 3,890.0 2,530.0 2,500.0 -

Table3-39 Monitoring Point Analysis October '00 ELEMENT M - 1 M - 2 M - 3 M - 4 M - 4A M - 4B M - 5 M - 6 M - 7 STANDARD

Q [lts/seg] 13.78 ----- 68.80 47.04 53.90 - pH 7.40 7.40 7.78 3.77 3.87 3.41 4.56 5.20 6.98 6,0 - 8,5 t° [°C] 16.7 16.6 14.4 22.8 17.8 18.4 19.0 19.7 15.2 < 40,0 Fe Total [mg/L] < 0.1 < 0.1 < 0.1 11,140.0 4,340.0 18.0 820.0 37.0 < 0.1 10.0 Fe +2 [mg/L] nd nd nd 10,860.0 4,210.0 nd 720.0 nd nd - Cu [mg/L] < 0.05 < 0.05 < 0.05 72.0 217.0 225.00 38.0 8.6 < 0.05 3.0 Al [mg/L] < 1.0 < 1.0 < 1.0 1,930.00 479.00 87.0 45.0 4.8 < 1.0 10.0 Mn [mg/L] < 0.05 < 0.05 < 0.05 285.00 173.00 48.00 34.00 16.00 0.20 3.0 Cl [mg/L] 71.0 155.0 12.0 < 10,0 13.0 47.0 78.0 111.0 202.0 2,000.0 As [mg/L] < 0.03 < 0.03 < 0.03 0.83 < 0.03 < 0.03 < 0.03 < 0.03 < 0.03 1.00 Hg [mg/L] < 0.001 0.002 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 0.01 Zn [mg/L] < 0.05 0.13 < 0.05 71.00 83.00 10.00 8.20 2.70 < 0.05 20.00 Mo [mg/L] < 0.01 < 0.01 < 0.01 0.03 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 2.50 Cd [mg/L] < 0.01 < 0.01 < 0.01 0.20 0.32 0.03 0.01 < 0.01 < 0.01 0.30 SO4 [mg/L] 119.0 153.0 78.0 32,000.0 12,000.0 3,078.0 2,803.0 813.0 609.0 2,000.0 Cond. [µS/cm] 1,170.0 1,560.0 512.0 36,800.0 16,100.0 5,540.0 4,630.0 2,660.0 2,760.0 -

Table3-40 Monitoring Point Analysis November '00 ELEMENT M - 1 M - 2 M - 3 M - 4 M - 4A M - 4B M - 5 M - 6 M - 7 STANDARD

Q [lts/seg] 7.55 ----- 59.83 43.16 77.16 - pH 7.37 7.05 7.45 3.59 3.38 2.98 4.16 4.55 6.91 6,0 - 8,5 t° [°C] 18.4 18.0 15.5 23.7 20.6 19.9 21.7 23.9 15.8 < 40,0 Fe Total [mg/L] <0.1 <0.1 <0.1 16,000.0 4,920.0 16.0 516.0 66.0 <0.1 10.0 Fe +2 [mg/L] nd nd nd 15,740.0 4,820.0 nd nd nd nd - Cu [mg/L] 0.2 < 0.05 < 0.05 312.0 233.0 121.00 46.00 15.00 < 0.05 3.0 Al [mg/L] < 1.0 < 1.0 < 1.0 3,070.00 457.00 46.00 62.0 17.0 < 1.0 10.0 Mn [mg/L] < 0.05 < 0.05 < 0.05 267.00 190.00 33.00 42.00 19.00 0.10 3.0 Cl [mg/L] 62.0 106.0 11 < 10,0 17.0 52.0 73.0 100.0 190.0 2,000.0 As [mg/L] < 0.03 < 0.03 < 0.03 4.80 < 0.03 < 0.03 < 0.03 < 0.03 < 0.03 1.00 Hg [mg/L] < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 0.01 Zn [mg/L] 0.05 0.09 < 0.05 74.00 70.00 6.90 11.00 4.60 < 0.05 20.00 Mo [mg/L] < 0.01 < 0.01 < 0.01 0.05 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 2.50 Cd [mg/L] < 0.01 < 0.01 < 0.01 0.30 0.33 0.15 0.03 0.01 < 0.01 0.30 SO4 [mg/L] 149.0 160.0 99 59000.0 21000.0 4739.0 3676.0 1687.0 747.0 2,000.0 Cond. [µS/cm] 1,210.0 1,430.0 512 46,600.0 16,600.0 4,910.0 5,450.0 3,500.0 2,790.0 -

nd : not determined. M-1: The Ingenio river (the upper stream of the plant). M-2: Spring water for drinking. M-3: Industrial water (Talhuen water). M-4: Waste water from precipitation process. M-4A: Infiltrate drainage at downstream of evaporation pond. M-4B: Infiltrate drainage at upstream of evaporation pond. M-5: The Ingenio river (500 m down stream of the plant). M-6: The Ingenio river (2 Km down stream of the plant). M-7: The Ingenio river (5 Km down stream of the plant). STANDARD : The reguration for discharge of effluent to subjects which have capacity of natural purification.

3-79 Table3-41 Monitoring Point Analysis December '00 ELEMENT M - 1 M - 2 M - 3 M - 4 M - 4A M - 4B M - 5 M - 6 M - 7 STANDARD

Q [lts/seg] 6.08 ----- 72.09 42.81 42.79 - pH 7.42 7.10 7.41 3.74 .3.70 2.73 4.17 4.50 6.95 6,0 - 8,5 t° [°C] 20.5 20.4 19.2 27.5 29.8 27.7 24.7 28.1 16.1 < 40,0 Fe Total [mg/L] < 0.1 0.1 < 0.1 19,590.0 15,390.0 3,180.0 281.0 70.0 0.2 10.0 Fe +2 [mg/L] nd nd nd 19,390.0 14,980.0 3,080.0 nd nd nd - Cu [mg/L] < 0.05 < 0.05 0.05 273.0 209.0 110.0 53.0 18.0 < 0.05 3.0 Al [mg/L] < 1.0 < 1.0 < 1.0 3,190.00 1,930.00 165.00 58.0 35.0 < 1.0 10.0 Mn [mg/L] < 0.05 < 0.05 < 0.05 625.00 392.00 195.00 41.00 14.00 0.10 3.0 Cl [mg/L] 69.0 132.0 11.0 < 10.0 < 10.0 24.0 78.0 76.0 173.0 2,000.0 As [mg/L] < 0.03 < 0.03 < 0.03 0.76 0.08 < 0.03 < 0.03 < 0.03 < 0.03 1.00 Hg [mg/L] < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 0.01 Zn [mg/L] 0.05 < 0.05 < 0.05 137.00 96.00 51.00 7.90 4.90 0.06 20.00 Mo [mg/L] < 0.01 < 0.01 < 0.01 0.30 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 2.50 Cd [mg/L] < 0.01 < 0.01 < 0.01 0.31 0.28 0.20 0.04 0.03 < 0.01 0.30 SO4 [mg/L] 132.0 148.0 76.0 56,000.0 54,000.0 12,000.0 2,458.0 1,605.0 729.0 2,000.0 Cond. [µS/cm] 1,020.0 1,050.0 456.0 44,900.0 38,700.0 15,500.0 2,450.0 839.0 926.0 -

Table3-42 Monitoring Point Analysis January '01 ELEMENT M - 1 M - 2 M - 3 M - 4 M - 4A M - 4B M - 5 M - 6 M - 7 STANDARD

Q [lts/seg] 13.44 ----- 75.50 45.07 41.45 - pH 7.24 7.08 7.48 3.68 3.82 nd 4.49 4.57 6.52 6,0 - 8,5 t° [°C] 18.8 18.8 16.5 27.9 26.9 nd 19.8 20.4 16.9 < 40,0 Fe Total [mg/L] < 0.1 < 0.1 < 0.1 18,660.0 3,380.0 nd 291.0 92.0 0.30 10.0 Fe +2 [mg/L] nd nd nd 17,640.0 3,280.0 nd nd nd nd - Cu [mg/L] < 0.05 < 0.05 < 0.05 339.0 85.0 nd 35.0 17.0 < 0.05 3.0 Al [mg/L] < 1.0 < 1.0 < 1.0 3,710.0 136.0 nd 48.0 16.0 < 1.0 10.0 Mn [mg/L] < 0.05 < 0.05 0.05 319.0 159.0 nd 38.0 22.0 < 0.05 3.0 Cl [mg/L] 49.0 82.0 < 10.0 20.0 12.0 nd 49.0 65.0 182.0 2,000.0 As [mg/L] < 0.03 < 0.03 < 0.03 0.16 0.10 nd < 0.03 < 0.03 < 0.03 1.00 Hg [mg/L] < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 nd < 0.001 < 0.001 < 0.001 0.01 Zn [mg/L] 0.07 < 0.05 0.10 136.0 44.00 nd 8.8 5.10 0.09 20.0 Mo [mg/L] < 0.01 < 0.01 < 0.01 0.35 < 0.01 nd < 0.01 < 0.01 < 0.01 2.5 Cd [mg/L] < 0.01 < 0.01 < 0.01 3.60 0.19 nd 0.03 < 0.01 < 0.01 0.30 SO4 [mg/L] 161.0 163.0 86.0 69,000.0 13,000.0 nd 3,351.0 1,881.0 883.0 2,000.0 Cond. [µS/cm] 1,000.0 1,150.0 446.0 43,500.0 11,400.0 nd 4,330.0 3,370.0 2,660.0 -

Table3-43 Monitoring Point Analysis February '01 ELEMENT M - 1 M - 2 M - 3 M - 4 M - 4A M - 4B M - 5 M - 6 M - 7 STANDARD

Q [lts/seg] 17.76 ----- 76.45 54.91 55.29 - pH 7.15 7.36 7.46 3.38 3.60 2.91 4.43 4.52 6.62 6,0 - 8,5 t° [°C] 21.2 20.9 19.3 27.9 20.7 22.2 22.8 26.0 18.9 < 40,0 Fe Total [mg/L] < 0.1 < 0.1 < 0.1 28,620.0 5,130.0 29.0 291.0 106.0 0.2 10.0 Fe +2 [mg/L] nd nd nd 28,520.0 4,820.0 nd nd nd nd nd Cu [mg/L] < 0.05 < 0.05 < 0.05 277.0 272.0 13.0 45.0 28.0 < 0.05 3.0 Al [mg/L] < 1.0 < 1.0 < 1.0 5,360.0 551.0 9.19 60.0 45.0 < 1.0 10.0 Mn [mg/L] < 0.05 < 0.05 < 0.05 371.0 230.0 20.0 34.0 25.0 0.31 3.0 Cl [mg/L] 57.0 122.0 < 10.0 19.0 12.0 59.0 65.0 84.0 181.0 2,000.0 As [mg/L] < 0.03 < 0.03 < 0.03 0.76 0.08 < 0.03 < 0.03 < 0.03 < 0.03 1.00 Hg [mg/L] < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 0.01 Zn [mg/L] < 0.05 < 0.05 < 0.05 181.0 84.0 1.31 10.0 7.1 0.36 20.0 Mo [mg/L] < 0.01 < 0.01 < 0.01 1.55 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 2.5 Cd [mg/L] < 0.01 < 0.01 < 0.01 1.56 0.29 0.01 0.04 0.02 < 0.01 0.30 SO4 [mg/L] 166.0 180.0 96.0 102,000.0 22,000.0 2,779.0 3,319.0 3,147.0 1,008.0 2,000.0 Cond. [µS/cm] 533.0 1,170.0 297.0 9,930.0 6,780.0 3,270.0 4,580.0 3,800.0 1,920.0 -

nd : not determined. M-1: The Ingenio river (the upper stream of the plant). M-2: Spring water for drinking. M-3: Industrial water (Talhuen water). M-4: Waste water from precipitation process. M-4A: Infiltrate drainage at downstream of evaporation pond. M-4B: Infiltrate drainage at upstream of evaporation pond. M-5: The Ingenio river (500 m down stream of the plant). M-6: The Ingenio river (2 Km down stream of the plant). M-7: The Ingenio river (5 Km down stream of the plant). STANDARD : The reguration for discharge of effluent to subjects which have capacity of natural purification.

3-80 Table3-44 Monitoring Point Analysis March '01 ELEMENT M - 1 M - 2 M - 3 M - 4 M - 4A M - 4B M - 5 M - 6 M - 7 STANDARD

Q [lts/seg] 16.05 ----- 81.61 78.46 68.14 - pH 7.69 7.70 nd 3.80 3.34 3.43 4.82 5.17 7.22 6,0 - 8,5 t° [°C] 19.5 17.6 nd 29.1 21.1 23.4 27.9 26.3 16.2 < 40,0 Fe Total [mg/L] < 0.1 < 0.1 nd 25,600.0 3,630.0 16.0 305.0 40.0 < 0.1 10.0 Fe +2 [mg/L] nd nd nd 24,630.0 3,520.0 nd nd nd nd - Cu [mg/L] < 0.05 < 0.05 nd 366.0 85.0 9.30 40.0 17.0 0.11 3.0 Al [mg/L] < 1.0 < 1.0 nd 5,900.0 170.0 9.6 63.0 25.0 < 1.0 10.0 Mn [mg/L] < 0.05 < 0.05 nd 229.0 213.0 18.0 42.0 17.0 1.50 3.0 Cl [mg/L] 58.0 96.0 nd 15.0 24.0 64.0 62.0 73.0 140.0 2,000.0 As [mg/L] < 0.03 < 0.03 nd 33.0 < 0.03 < 0.03 < 0.03 < 0.03 < 0.03 1.00 Hg [mg/L] < 0.001 < 0.001 nd < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 0.01 Zn [mg/L] 0.05 0.18 nd 109.0 43.0 0.56 8.8 4.0 0.63 20.0 Mo [mg/L] < 0.01 0.03 nd 0.86 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 2.5 Cd [mg/L] < 0.01 < 0.01 nd 1.22 0.31 < 0.01 0.06 < 0.01 < 0.01 0.30 SO4 [mg/L] 156.0 228.0 nd 95,000.0 16,000.0 2,270.0 3,190.0 1,820.0 1,250.0 2,000.0 Cond. [µS/cm] 885.0 950.0 nd 42,000.0 10,200.0 3,040.0 4,120.0 2,750.0 2,200.0 -

Table3-45 Monitoring Point Analysis April '01 ELEMENT M - 1 M - 2 M - 3 M - 4 M - 4A M - 4B M - 5 M - 6 M - 7 STANDARD

Q [lts/seg] 16.97 -----103.00 66.24 75.92 - pH 7.67 7.99 7.80 3.91 4.11 3.53 4.99 5.41 7.03 6,0 - 8,5 t° [°C] 14.4 7.7 10.1 22.9 14.8 11.6 17.1 18.2 11.1 < 40,0 Fe Total [mg/L] < 0.1 < 0.1 < 0.1 25,000.0 6,300.0 18.0 274.0 24.0 < 0.1 10.0 Fe +2 [mg/L] nd nd nd 24,280.0 5,380.0 nd nd nd nd - Cu [mg/L] < 0.05 < 0.05 < 0.05 442.0 203.0 7.7 35.0 11.0 0.16 3.0 Al [mg/L] < 1.0 < 1.0 < 1.0 3,000.0 345.0 6.0 50.0 15.0 < 1.0 10.0 Mn [mg/L] < 0.05 < 0.05 < 0.05 633.0 291.0 12.0 26.0 8.1 1.70 3.0 Cl [mg/L] 61.0 105.0 < 10.0 18.0 26.0 70.0 60.0 67.0 150.0 2,000.0 As [mg/L] < 0.03 < 0.03 < 0.03 40.0 < 0.03 < 0.03 < 0.03 < 0.03 < 0.03 1.00 Hg [mg/L] < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 0.01 Zn [mg/L] < 0.05 0.26 0.09 194.0 58.0 0.61 7.9 2.9 0.45 20.0 Mo [mg/L] < 0.01 < 0.01 < 0.01 0.78 0.27 < 0.01 < 0.01 < 0.01 < 0.01 2.5 Cd [mg/L] < 0.01 < 0.01 < 0.01 1.39 0.33 < 0.01 0.06 0.03 < 0.01 0.30 SO4 [mg/L] 139.0 176.0 94.0 89,000.0 22,000.0 1,908.0 3,348.0 1,353.0 1,012.0 2,000.0 Cond. [µS/cm] 764.0 1,129.0 417.0 56,500.0 14,450.0 3,760.0 5,170.0 3,050.0 2,760.0 -

Table3-46 Monitoring Point Analysis May '01 ELEMENT M - 1 M - 2 M - 3 M - 4 M - 4A M - 4B M - 5 M - 6 M - 7 STANDARD

Q [lts/seg] 22.89 -----106.36 116.50 112.93 - pH 7.65 7.61 7.00 3.85 3.20 3.41 4.80 5.51 7.13 6,0 - 8,5 t° [°C] 18.0 15.0 14.0 21.0 19.0 18.0 21.0 20.0 16.0 < 40,0 Fe Total [mg/L] < 0.1 < 0.1 < 0.1 14,390.0 3,500.0 12.0 770.0 19.0 0.2 10.0 Fe +2 [mg/L] nd nd nd 13,600.0 2,340.0 nd 560.0 nd nd - Cu [mg/L] < 0.05 < 0.05 < 0.05 242.0 80.0 34.0 29.0 11.0 0.17 3.0 Al [mg/L] < 1.0 < 1.0 < 1.0 3,000.0 156.0 81.0 219.0 91.0 < 1.0 10.0 Mn [mg/L] < 0.05 < 0.05 < 0.05 404.0 179.0 18.0 25.0 8.5 1.3 3.0 Cl [mg/L] 48.0 92.0 < 10.0 < 10.0 39.0 43.0 61.0 71.0 143.0 2,000.0 As [mg/L] < 0.005 < 0.005 < 0.005 1.70 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 1.00 Hg [mg/L] < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 0.01 Zn [mg/L] < 0.05 < 0.05 < 0.05 148.0 41.0 1.7 8.7 2.2 0.81 20.0 Mo [mg/L] < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 2.5 Cd [mg/L] < 0.01 < 0.01 < 0.01 1.94 0.12 0.03 0.06 0.03 < 0.01 0.30 SO4 [mg/L] 135.0 150.0 89.0 45,000.0 13,000.0 2,375.0 2,775.0 975.0 838.0 2,000.0 Cond. [µS/cm] 907.0 1,101.0 453.0 38,700.0 10,970.0 4,140.0 4,840.0 2,790.0 2,500.0 -

nd : not determined. M-1: The Ingenio river (the upper stream of the plant). M-2: Spring water for drinking. M-3: Industrial water (Talhuen water). M-4: Waste water from precipitation process. M-4A: Infiltrate drainage at downstream of evaporation pond. M-4B: Infiltrate drainage at upstream of evaporation pond. M-5: The Ingenio river (500 m down stream of the plant). M-6: The Ingenio river (2 Km down stream of the plant). M-7: The Ingenio river (5 Km down stream of the plant). STANDARD : The reguration for discharge of effluent to subjects which have capacity of natural purification.

3-81 Table3-47 Monitoring Point Analysis June '01 ELEMENT M - 1 M - 2 M - 3 M - 4 M - 4A M - 4B M - 5 M - 6 M - 7 STANDARD

Q [lts/seg] 37.84 ----- 94.96 143.41 120.14 - pH 7.50 7.58 7.93 2.63 3.71 2.89 5.37 5.29 6.96 6,0 - 8,5 t° [°C] 15.1 13.8 14.4 24.4 20.9 13.9 17.5 19.2 11.5 < 40,0 Fe Total [mg/L] 0.1 < 0.1 0.2 15,000.0 4200.0 14.0 33.0 0.6 0.2 10.0 Fe +2 [mg/L] nd nd nd 13,680.0 3,200.0 nd nd nd nd - Cu [mg/L] < 0.05 < 0.05 < 0.05 317.0 191.0 8.9 15.0 6.9 0.06 3.0 Al [mg/L] < 1.0 < 1.0 < 1.0 3,000.0 406.0 3.0 23.0 10.0 < 1.0 10.0 Mn [mg/L] < 0.05 < 0.05 < 0.05 710.0 276.0 17.0 17.0 9.7 3.3 3.0 Cl [mg/L] 41.0 85.00 < 10,0 17.0 132.0 43.0 61.0 63.0 118.0 10.0 As [mg/L] < 0.005 < 0.005 < 0.005 5.20 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 3.0 Hg [mg/L] < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 2,000.0 Zn [mg/L] < 0.05 0.10 < 0.05 243.0 55.0 1.0 3.6 2.5 0.36 1.00 Mo [mg/L] < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 0.01 Cd [mg/L] < 0.01 < 0.01 < 0.01 1.85 0.31 0.02 0.04 0.03 < 0.01 0.30 SO4 [mg/L] 117.0 141.0 88.0 56,000.0 18,000.0 1,950.0 1,400.0 863.0 725.0 2,000.0 Cond. [µS/cm] 960.0 1,318.0 465.0 57,400.0 13,700.0 3,140.0 2,340.0 1,871.0 2,020.0 -

Table3-48 Monitoring Point Analysis July '01 ELEMENT M - 1 M - 2 M - 3 M - 4 M - 4A M - 4B M - 5 M - 6 M - 7 STANDARD

Q [lts/seg] 83.80 -----140.62 178.96 182.49 - pH 7.82 7.34 7.87 3.50 2.90 3.47 5.43 5.89 7.15 6,0 - 8,5 t° [°C] 16.7 14.9 15.9 20.4 17.9 16.8 17.5 19.0 14.2 < 40,0 Fe Total [mg/L] < 0.1 < 0.1 < 0.1 23,470.0 5,310.0 130.0 240.0 107.0 < 0.1 10.0 Fe +2 [mg/L] nd nd nd 15,340.0 2,560.0 nd 230.0 nd nd - Cu [mg/L] < 0.05 < 0.05 < 0.05 184.0 58.0 290.0 18.0 8.0 < 0.05 3.0 Al [mg/L] < 1.0 < 1.0 < 1.0 3,448.0 135.0 184.0 47.0 28.0 1.0 10.0 Mn [mg/L] < 0.05 < 0.05 < 0.05 358.0 182.0 102.0 24.0 10.0 3.2 3.0 Cl [mg/L] 52.0 88.0 < 10,0 < 10,0 34.0 25.0 58.0 62.0 127.0 2,000.0 As [mg/L] < 0.005 < 0.005 < 0.005 1.40 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 1.00 Hg [mg/L] < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 0.01 Zn [mg/L] < 0.05 < 0.05 < 0.05 165.0 39.0 20.0 5.0 1.6 0.16 20.0 Mo [mg/L] < 0.01 0.01 0.01 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 2.5 Cd [mg/L] < 0.01 < 0.01 < 0.01 1.62 0.89 0.08 0.03 0.02 < 0.01 0.30 SO4 [mg/L] 146.0 169.0 68.0 50,000.0 9,400.0 4,275.0 1,250.0 675.0 662.0 2,000.0 Cond. [µS/cm] 944.0 1,346.0 465.0 44,200.0 8,950.0 5,180.0 2,330.0 1,607.0 1,981.0 -

Table3-49 Monitoring Point Analysis August '01 ELEMENT M - 1 M - 2 M - 3 M - 4 M - 4A M - 4B M - 5 M - 6 M - 7 STANDARD

Q [lts/seg] 61.63 -----128.81 165.52 137.71 - pH 7.64 7.49 7.36 3.10 3.95 3.53 5.18 5.45 6.80 6,0 - 8,5 t° [°C] 15.5 14.9 14.0 18.0 16.6 15.5 16.2 16.6 13.6 < 40,0 Fe Total [mg/L] < 0.1 < 0.1 < 0.1 9,800.0 3,800.0 25.0 78.0 0.30 0.30 10.0 Fe +2 [mg/L] nd nd nd nd nd nd - Cu [mg/L] < 0.05 < 0.05 < 0.05 99.0 190.0 401.00 17.0 5.80 < 0.05 3.0 Al [mg/L] < 1.0 < 1.0 < 1.0 1,000.0 392.0 250.0 26.0 7.0 < 1.0 10.0 Mn [mg/L] < 0.05 < 0.05 < 0.05 171.0 258.0 144.0 22.0 6.8 < 0.05 3.0 Cl [mg/L] 44.0 91.0 < 10,0 < 10,0 18.0 16.0 55.0 85.0 134.0 2,000.0 As [mg/L] < 0.005 < 0.005 < 0.005 0.02 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 1.00 Hg [mg/L] < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 0.01 Zn [mg/L] 0.11 0.12 0.09 72.0 59.0 26.0 5.5 2.2 0.23 20.0 Mo [mg/L] < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 2.5 Cd [mg/L] < 0.01 < 0.01 < 0.01 0.96 0.22 0.14 < 0.01 < 0.01 < 0.01 0.30 SO4 [mg/L] 116.0 156.0 86.0 45,000.0 21,000.0 7,050.0 1975.0 875.0 712.0 2,000.0 Cond. [µS/cm] 1,084.0 1,468.0 544.0 37,900.0 23,200.0 11,400.0 4,540.0 2,290.0 2,730.0 -

nd : not determined. M-1: The Ingenio river (the upper stream of the plant). M-2: Spring water for drinking. M-3: Industrial water (Talhuen water). M-4: Waste water from precipitation process. M-4A: Infiltrate drainage at downstream of evaporation pond. M-4B: Infiltrate drainage at upstream of evaporation pond. M-5: The Ingenio river (500 m down stream of the plant). M-6: The Ingenio river (2 Km down stream of the plant). M-7: The Ingenio river (5 Km down stream of the plant). STANDARD : The reguration for discharge of effluent to subjects which have capacity of natural purification.

3-82 Table3-50 Monitoring Point Analysis September '01 ELEMENT M - 1 M - 2 M - 3 M - 4 M - 4A M - 4B M - 5 M - 6 M - 7 STANDARD

Q [lts/seg] 25.29 ----- 73.32 80.83 77.10 - pH 7.98 7.68 7.52 2.97 2.91 3.49 4.99 5.53 7.20 6,0 - 8,5 t° [°C] 19.1 19.8 17.7 25.3 26.3 24.7 20.7 24.6 15.6 < 40,0 Fe Total [mg/L] < 0.1 < 0.1 < 0.1 15,400.0 2,090.0 7.3 106.0 < 0.1 < 0.1 10.0 Fe +2 [mg/L] nd nd nd 14,430.0 1,000.0 nd nd nd nd - Cu [mg/L] < 0.05 < 0.05 < 0.05 267.0 69.0 1200.0 22.0 5.8 0.05 3.0 Al [mg/L] < 1.0 < 1.0 < 1.0 2,000.0 142.0 652.0 37.0 4.0 < 1.0 10.0 Mn [mg/L] < 0.05 < 0.05 < 0.05 116.0 59.0 75.0 12.0 7.6 0.07 3.0 Cl [mg/L] 53.0 116.00 12.0 < 10.0 20.0 < 10.0 67.0 83.0 159.0 2,000.0 As [mg/L] < 0.005 < 0.005 < 0.005 0.54 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 1.00 Hg [mg/L] < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 0.01 Zn [mg/L] < 0.05 < 0.05 0.08 201.0 37.0 68.0 5.2 1.80 1.30 20.0 Mo [mg/L] < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 0.12 < 0.01 < 0.01 2.5 Cd [mg/L] < 0.01 < 0.01 < 0.01 1.38 0.19 0.41 < 0.01 < 0.01 < 0.01 0.30 SO4 [mg/L] 127.0 171.0 89.0 139,000.0 15,000.0 4,100.0 2,275.0 788.0 838.0 2,000.0 Cond. [µS/cm] 839.0 1,114.0 424.0 49,400.0 10,660.0 5,400.0 2,800.0 1,442.0 1,790.0 -

Table3-51 Monitoring Point Analysis October '01 ELEMENT M - 1 M - 2 M - 3 M - 4 M - 4A M - 4B M - 5 M - 6 M - 7 STANDARD

Q [lts/seg] 14.47 ----- 74.59 93.02 77.79 - pH 7.19 7.41 7.60 2.56 3.71 2.82 4.41 4.71 6.64 6,0 - 8,5 t° [°C] 18.5 16.5 15.4 25.4 22.4 23.1 20.8 23.3 17.1 < 40,0 Fe Total [mg/L] < 0.1 < 0.1 < 0.1 17,110.0 5,740.0 138.0 222.0 33.0 < 0.1 10.0 Fe +2 [mg/L] nd nd nd 16,090.0 4,630.0 nd nd nd nd - Cu [mg/L] < 0.05 < 0.05 < 0.05 295.0 349.0 350.0 31.0 15.0 0.05 3.0 Al [mg/L] < 1.0 < 1.0 < 1.0 3,000.0 786.0 151.0 70.0 35.0 < 1.0 10.0 Mn [mg/L] < 0.05 < 0.05 < 0.05 638.0 420.0 161.0 8.9 4.9 1.20 3.0 Cl [mg/L] 61.0 110.0 11.0 < 10.0 12.0 26.0 65.0 73.0 150.0 10.0 As [mg/L] 0.008 0.010 < 0.005 0.008 0.025 < 0.005 < 0.005 < 0.005 < 0.005 3.0 Hg [mg/L] < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 2,000.0 Zn [mg/L] 0.31 < 0.05 0.35 229.00 231.00 94.00 8.90 4.90 0.48 1.00 Mo [mg/L] < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 0.21 < 0.01 < 0.01 < 0.01 0.01 Cd [mg/L] < 0.01 < 0.01 < 0.01 2.14 0.39 0.10 < 0.01 < 0.01 < 0.01 0.30 SO4 [mg/L] 129.0 176.0 96.0 56,000.0 22,000.0 7,600.0 2,988.0 1,600.0 900.0 2,000.0 Cond. [µS/cm] 1,094.0 1,323.0 511.0 49,900.0 26,600.0 10,500.0 5,650.0 3,890.0 2,710.0 -

Table3-52 Monitoring Point Analysis November '01 ELEMENT M - 1 M - 2 M - 3 M - 4 M - 4A M - 4B M - 5 M - 6 M - 7 STANDARD

Q [lts/seg] 12.46 ----- 74.17 69.65 67.76 - pH 7.24 7.48 7.89 3.07 2.67 3.41 4.14 4.47 6.58 6,0 - 8,5 t° [°C] 25.3 33.1 20.1 25.1 27.1 29.7 25.6 28.0 25.0 < 40,0 Fe Total [mg/L] < 0.1 < 0.1 0.3 12,150.0 5,810.0 450.0 458.0 31.0 0.1 10.0 Fe +2 [mg/L] nd nd nd 11,770.0 4,580.0 110.0 nd nd nd - Cu [mg/L] < 0.05 < 0.05 < 0.05 200.0 253.0 156.0 50.0 15.0 0.12 3.0 Al [mg/L] < 1.0 < 1.0 < 1.0 1,000.0 52.0 66.0 78.0 27.0 < 1.0 10.0 Mn [mg/L] < 0.05 < 0.05 < 0.05 482.0 310.0 81.0 62.0 16.0 1.60 3.0 Cl [mg/L] 60.0 109.0 < 10.0 < 10.0 < 10.0 33.0 49.0 67.0 164.0 2,000.0 As [mg/L] < 0.005 < 0.005 < 0.005 0.049 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 1.00 Hg [mg/L] < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 0.01 Zn [mg/L] 0.08 < 0.05 0.08 241.0 88.0 7.3 12.0 4.0 0.55 20.0 Mo [mg/L] < 0.01 < 0.01 < 0.01 < 0.01 0.03 < 0.01 < 0.01 < 0.01 < 0.01 2.5 Cd [mg/L] < 0.01 < 0.01 < 0.01 1.84 0.37 0.10 0.06 0.01 < 0.01 0.30 SO4 [mg/L] 101.0 137.0 92.0 36,000.0 19,000.0 6,000.0 3,740.0 1,488.0 800.0 2,000.0 Cond. [µS/cm] 1,260.0 1,482.0 627.0 47,800.0 32,400.0 11,200.0 8,670.0 4,820.0 3,490.0 -

nd : not determined. M-1: The Ingenio river (the upper stream of the plant). M-2: Spring water for drinking. M-3: Industrial water (Talhuen water). M-4: Waste water from precipitation process. M-4A: Infiltrate drainage at downstream of evaporation pond. M-4B: Infiltrate drainage at upstream of evaporation pond. M-5: The Ingenio river (500 m down stream of the plant). M-6: The Ingenio river (2 Km down stream of the plant). M-7: The Ingenio river (5 Km down stream of the plant). STANDARD : The reguration for discharge of effluent to subjects which have capacity of natural purification.

3-83 Table3-53 Monitoring Point Analysis Diciembre '01 ELEMENT M - 1 M - 2 M - 3 M - 4 M - 4A M - 4B M - 5 M - 6 M - 7 STANDARD

Q [lts/seg] 11.71 ----- 74.19 82.93 65.43 - pH 7.03 7.18 6.75 3.35 3.21 2.48 4.19 4.87 6.37 6,0 - 8,5 t° [°C] 18.7 19.2 16.1 24.2 23.2 22.5 22.5 23.2 20.3 < 40,0 Fe Total [mg/L] < 0.1 < 0.1 < 0.1 10,700.0 5,140.0 360.0 821.0 27.0 0.1 10.0 Fe +2 [mg/L] nd nd nd 10,490.0 4,610.0 60.0 nd nd nd - Cu [mg/L] < 0.05 < 0.05 < 0.05 154.0 233.0 71.0 57.0 12.0 0.35 3.0 Al [mg/L] < 1.0 < 1.0 < 1.0 2,000.0 560.0 46.0 98.0 23.0 < 1.0 10.0 Mn [mg/L] < 0.05 < 0.05 < 0.05 568.0 371.0 83.0 70.0 20.0 5.40 3.0 Cl [mg/L] 68.0 97.00 15.0 < 10.0 < 10.0 40.0 41.0 57.0 172.0 2,000.0 As [mg/L] < 0.005 < 0.005 < 0.005 2.4 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 1.00 Hg [mg/L] < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 0.01 Zn [mg/L] 0.30 0.40 0.32 195.0 68.0 6.4 13.0 3.60 1.10 20.0 Mo [mg/L] < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 0.12 < 0.01 < 0.01 2.5 Cd [mg/L] < 0.01 < 0.01 < 0.01 2.18 0.25 0.02 < 0.01 < 0.01 < 0.01 0.30 SO4 [mg/L] 100.0 119.0 82.0 36,000.0 20,000.0 5,600.0 3,700.0 1,225.0 925.0 2,000.0 Cond. [µS/cm] 1,161.0 1,282.0 535.0 36,800.0 25,200.0 10,400.0 6,480.0 3,400.0 2,940.0 -

Table3-54 Monitoring Point Analysis January '02 ELEMENT M - 1 M - 2 M - 3 M - 4 M - 4A M - 4B M - 5 M - 6 M - 7 STANDARD

Q [lts/seg] 10.4 ----- 83.39 54.13 44.56 - pH 7.21 7.47 7.09 2.96 3.27 2.20 3.22 4.26 6.57 6,0 - 8,5 t° [°C] 19.2 18.2 16.6 25.1 21.3 21.00 22.2 21.3 19.0 < 40,0 Fe Total [mg/L] < 0.1 0.20 0.20 15,000.0 5,600.0 188.00 677.0 136.0 0.1 10.0 Fe +2 [mg/L] nd nd nd nd nd nd nd nd nd - Cu [mg/L] < 0.05 < 0.05 0.06 73.0 230.0 35.0 46.0 19.0 0.38 3.0 Al [mg/L] < 1.0 < 1.0 < 1.0 3,000.0 26.0 24.0 82.0 24.0 < 1.0 10.0 Mn [mg/L] < 0.05 < 0.05 < 0.05 544.0 333.0 72.0 80.0 37.0 6.00 3.0 Cl [mg/L] 65.0 115.0 18.0 < 10.0 37.0 64.0 72.0 82.0 200.0 10.0 As [mg/L] < 0.005 < 0.005 < 0.005 0.044 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 3.0 Hg [mg/L] < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 2,000.0 Zn [mg/L] 0.07 0.20 0.30 207.0 90.0 4.40 12.00 7.20 0.98 1.00 Mo [mg/L] < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 < 0.01 0.01 Cd [mg/L] < 0.01 < 0.01 < 0.01 1.50 0.32 0.02 0.05 < 0.01 < 0.01 0.30 SO4 [mg/L] 142.0 183.0 105.0 43,000.0 20,000.0 5,100.0 4,100.0 2,050.0 1,000.0 2,000.0 Cond. [µS/cm] 8.63 12.2 9.29 29.4 12.1 26.8 6.77 17.0 13.6 -

Table3-55 Monitoring Point Analysis February '02 ELEMENT M - 1 M - 2 M - 3 M - 4 M - 4A M - 4B M - 5 M - 6 M - 7 STANDARD

Q [lts/seg] 34.68 -----133.57 117.69 76.60 - pH 7.12 7.21 7.01 2.96 3.51 5.03 3.53 4.89 6.22 6,0 - 8,5 t° [°C] 18.9 18.9 17.5 25.2 19.3 20.1 19.9 19.8 18.0 < 40,0 Fe Total [mg/L] 0.2 0.2 0.1 18,000.0 866.0 982.0 956.0 36.0 < 0.1 10.0 Fe +2 [mg/L] nd nd nd nd nd nd nd nd nd - Cu [mg/L] < 0.05 < 0.05 < 0.05 212.0 198.0 0.84 68.0 10.0 0.67 3.0 Al [mg/L] < 1.0 < 1.0 < 1.0 4,000.0 425.0 7.0 104.0 12.0 < 1.0 10.0 Mn [mg/L] < 0.05 < 0.05 < 0.05 516.0 294.0 79.0 99.0 20.0 7.4 3.0 Cl [mg/L] ------2,000.0 As [mg/L] ------1.00 Hg [mg/L] ------0.01 Zn [mg/L] ------20.0 Mo [mg/L] ------2.5 Cd [mg/L] ------0.30 SO4 [mg/L] 133.0 174.0 82.0 29,000.0 18,000.0 6,300.0 4,800.0 1,359.0 912.0 2,000.0 Cond. [µS/cm] ------

nd : not determined. M-1: The Ingenio river (the upper stream of the plant). M-2: Spring water for drinking. M-3: Industrial water (Talhuen water). M-4: Waste water from precipitation process. M-4A: Infiltrate drainage at downstream of evaporation pond. M-4B: Infiltrate drainage at upstream of evaporation pond. M-5: The Ingenio river (500 m down stream of the plant). M-6: The Ingenio river (2 Km down stream of the plant). M-7: The Ingenio river (5 Km down stream of the plant). STANDARD : The reguration for discharge of effluent to subjects which have capacity of natural purification.

3-84

４．Technical Transfer of Iron Oxidizing Bacteria Method ４．Technical Transfer of Iron Oxidizing Bacteria Method

4.1 Basic Laboratory Tests Basic laboratory tests were conducted during the first period of Field Survey in Chile (Oct.,1999 through Dec.) and the following works in Japan. At the Field Survey, continuous oxidation tests with help of iron-oxidizing bacteria and also neutralization with local alkaline reagents were carried out for the design of model plant. These oxidation tests were traced in Japan with the bacteria sample taken from the Ovalle and Andacollo plant as well to compare with the results obtained in Chile and to make up a demonstration test program at the model plant. 4.1.1 Basic Laboratory Tests (1) at the First Field Survey The major items are summarized as follows. ・ Survey of iron-oxidizing bacteria ・ Oxidation tests ・ Confirmation of negative factors against bacteria activity ・ Neutralization tests using local reagents ・ Flocculation and settling tests ・ Filtering tests

(1) Survey of Iron-Oxidizing Bacteria 1) Purpose Back in 1998, iron-oxidizing bacteria was already confirmed to exist in an evaporating pond of the Ovalle plant during the preparatory studies. This time another sample was taken from Ovalle waste solution and cultivated to reconfirm the existence. 2) Method ① Samples surveyed Test samples were taken on Nov. 5, 1999 from sediments around the evaporation ponds at the plant. Sediment of the waste solution pipe at the entrance to the first stage evaporation pond (pH: 3～4 by test paper) Sediment at and around the outlet pipe from the second stage pond (pH: 3) Sediment at the bottom of the outlet pipe from the first stage pond (pH: 3～４) ② Cultivation method The above three samples were separately vaccinated and cultivated on 9K medium1) and was observed appearance of colonies on silica gel medium.2) The bacteria that reveal the colonies can be identified as Thiobacillus ferrooxidans3). 3) Results ① Liquid culture Samples taken from the Ovalle plant on Nov. 8th , 1999 were vaccinated on 9K medium and cultivated by shaking at 30℃. Four days later, on Nov. 12th, growth of iron-oxidizing

4-1 bacteria was observed (cultivated solution turned red-brown) on the sample . Eight days later, on Nov. 16, the growth of bacteria was confirmed on all of the samples. By observing with a biological microscope, a large quantity of rod shape bacteria, Ｔhiobacillus ferrooxidans, were clearly found out. ② Plate culture On Nov．16th, 1999, two samples of the above cultivated solution (one is the fastest in bacteria growth and another is cultivated in Japan and brought back) were put on silica gel medium plate and cultivated at 30℃ so that bacteria colonies may break out. On Nov. 22nd , six days later, colonies were observed. These colonies were picked up onto 9K medium for another cultivation. ③ Preservation of Ovalle strain According to the above procedure, it was reconfirmed that iron-oxidizing bacteria live in the evaporating ponds of the Ovalle plant. This Ovalle strain has been preserved at the biochemical laboratory of El Salado plant on Chilean counterpart’s hands.

Table 4-1 Composition of 9K Medium1)

FeSO4･7H2O 44.22g (NH4)2SO4 3.0g K2HPO4 0.5g MgSO4･7H2O 0.5g KCl 0.1g Ca(NO3)2･4H2O 0.01g Distilled water 1000mL

pH adjusted at 2.0～2.5 with H2SO4

Table 4-2 Composition of Silica Gel Medium2)

Colloidal Silica No.30 900mL (Nissan Kagaku Co.,Ltd.)

(NH4)2SO4 2.1g K2HPO4 0.35g MgSO4･7H2O 0.07g KCl 0.35g Ca(NO3)2･4H2O 0.007g Distilled water 70mL pH adjusted at 5.7 with H2SO4

Saturated FeSO4 solution 30mL pH adjusted at 1.4 with H2SO4

4-2 (2) Oxidation Tests 1) Purpose Continuous oxidation tests of ferrous ion (Fe2+) in the Ovalle waste solution were carried out with help of locally habitant bacteria and also their efficiency was carefully observed in case the concentration of ferrous ion fluctuated. 2) Method ① Iron oxidizing bacteria Ovalle strain ② Test apparatus Bench unit (provided by JICA during the previous mini-project) ③ Forming bacteria carrier Here carrier means some substance implanted with bacteria. The carrier of oxidizing bacteria was prepared with use of the neutralization tank of the bench unit. ④ Continuous treatment tests a) Feed solution and test period Continuous tests were conducted as indicated in Table 4-3. Table 4-3 Basic Tests (1) - Feed Solution and Test Period Test period 11/19~11/24 (5 days) 11/24~11/29 (5 days) 11/29~12/3 (4 days) Feed solution Artificial solution Artificial solution Actual Ovalle solution Quality pH=3.5, Fe2+=27g/L pH=3.5, Fe2+=45g/L pH=3.3, Fe2+=26g/L To confirm start-up To confirm an effect of Test purpose To confirm adaptability condition quality fluctuation b) Test conditions Test conditions are shown in Table 4-4. Table 4-4 Basic Tests (1) - Test Conditions Test item Condition Volume of carrier recycled 300ml/min Volume of feed solution 100ml/min (=144L/day) Retention time in oxidation tank about 7.3 hour Volume of airblow 5.5m3/h/4 oxidation tanks Addition of flocculent 5mg/L (Mitsui CYTEC A-95) Addition of nutrient 10mg/L of (NH4)2HPO4 (5mg/L only at the beginning)

3) Test results Continuous oxidation was confirmed both in case of the artificial and actual waste solution. Oxidation rate is around 0.55g/L/h. As Fe2+ concentration in feed solution rises, also rises in the oxidation tank but oxidation rate remains nearly constant.

4-3

0.9 /h) /L 0.8 g (

te 0.7 a

R 0.6 n o i t 0.5 a d i 0.4 x O

s 0.3

u o r 0.2 r

F 0.1 0 0 50 100 150 200 250 300 350 Test Time (h)

Figure 4-1 Basic Tests (1) - Change in Oxidation Rate of Fe2+

) L

/ 40 g

(

n 35 o i 30 at r t 25 cen n 20 o

C 15 s u 10 o r r e 5 F 0 0 50 100 150 200 250 300 350 Test Time (h)

Feed Solution Oxidized Solution

Figure 4-2 Basic Tests (1) - Change in Fe2+ Concentration

4-4 (3) Confirmation Tests of Negative Factors against Bacteria Activity

1) Purpose One purpose is to find out the negative environment, if any, against bacteria activities by repeating cultivation with use of the actual waste solution. Another is to examine the necessity of any nutrient in the demonstration test run at the model plant.

2) Method ① Bacteria strain Ovalle strain is used as iron oxidizing bacteria. ② Addition of nutrient As a nutrient ammonium phosphate is added to the waste solution from Ovalle leaching plant. Table 4-5 Basic Tests (1) - Addition of Nutrient Test No. Nutrient addition (mg/L) 0 0.5 2.5 5 10

3) Results

(NH4)3PO4･3H2O, habitually employed as a nutrient, was not available at that time. So

the first cultivation was done on 9K medium (inorganic salt only) and then (NH4)2HPO4 (reagent) was used as a nutrient from the second one. The first cultivation was carried out with no pH adjustment. In the second cultivation and thereafter pH was adjusted at 2.5. In the first cultivation a large quantity of sediment was formed and seemed to hinder the growth of bacteria. Cultivation was done by dividing each solution of various condition into three test tubes (10mL each) and then by vaccinating 1mL of the previously cultivated solution of the same test number into each test tube. Accordingly, as cultivation was repeated, any influence of 9K medium would be reduced. The results are shown in the following Table, in which cultivation with no nutrient shows poorer bacteria growth as cultivation is repeated. This is understood that the nutrient brought with vaccination helped the growth first but became inefficient after repeating. The results indicate that some nutrient of ammonium phosphate is needed at least at the start-up of the model plant.

4-5 Table 4-6 Basic Tests (1) - Results of Repeated Cultivation

○First culture No. Nutrient 1st day 2nd day 3rd day 4th day 5th day 6th day 7th day 8th day Nothing －－－－－－－－－－－－＋＋＋＋＋＋ (1/20)×9K －－－－－－－－－－－－＋＋＋＋＋＋ (1/4)×9K －－－－－－－－－ ±±± ＋＋＋＋＋＋ (1/2)×9K －－－－－－－－－ ±±± ＋＋＋＋＋＋ (1)×9K －－－－－－－－－ ±±± ＋＋＋＋＋＋

○Second culture No. Nutrient 1st day 2nd day 3rd day 4th day 5th day 6th day 0mg/L －－－－－－－－－－±± ±±＋ 0.5mg/L －－－－－－ ±±± ±＋＋＋＋＋ 2.5mg/L －－－－－－ ±±± ±＋＋ ±＋＋ 5mg/L －－－－－－ ±±± ±＋＋ ±＋＋ 10mg/L －－－－－－ ±±± ±＋＋＋＋＋

○Third culture No. Nutrient 1st day 2nd day 3rd day 4th day 5th day 6th day 0mg/L －－－－－－－－－－－－ 0.5mg/L －－－－－－ ±±± ＋＋＋ 2.5mg/L －－－－－－ ±±± ＋＋＋ 5mg/L －－－－－－ ±±± ＋＋＋ 10mg/L －－－－－－ ±±± ＋＋＋

○Fourth culture No. Nutrient 1st day 2nd day 3rd day 4th day 5th day 6th day 7th day 0mg/L 0.5mg/L －－－－－－－－－ ±±± ＋＋＋ 2.5mg/L －－－－－－－－－ ±±± ＋＋＋ 5mg/L －－－－－－－－－ ±±± ＋＋＋ 10mg/L －－－－－－－－－ ±±± ＋＋＋

Notes －：no colored (no growth) ±：somewhat colored ＋：colored (growth)

4-6 (4) Neutralization, Filtering, Flocculation and Settling Tests 1) Purpose Neutralization, flocculation and settling tests were carried out on the actual Ovalle solution with local reagents, currently employed, for the design of neutralization circuit of the model plant. 2) Test items · Analysis of feed water (waste solution) · Neutralization tests with calcium carbonate · Neutralization tests with slaked lime · Filtering tests of neutralized sediment · Flocculation and settling tests with use of high polymer flocculent 3) Methods and results ① Analysis of the actual Ovalle waste solution a) Analysis of solution quality The analysis of a sample, which was taken on Nov., 5th at Ovalle and transported to the El Salado bio-chemical laboratory, is shown in Table 4-7. The Table also shows a comparative result assayed in Japan on the same sample. Table 4-8 shows an another result on a different sample taken two months ago and preserved at the laboratory. Table 4-7 Chemical Composition of the Actual Ovalle Solution (November 5th, 1999) Fe2+ T-Fe Cu Mn Zn Sn Al Cd Item pH (g/L) (g/L) (g/L) (g/L) (g/L) (mg/L) (g/L) (mg/L) El Salado 3.7 23.40 23.53 0.07 0.974 0.24 N.D. 9.7 0.18 Japan －－ 24.30 0.07 1.110 0.22 N.D. 4.4 0.70

Pb As Ca Mg Cr F- SO 2- Cl- Specific Item 4 (mg/L) (mg/L) (mg/L) (g/L) (mg/L) (mg/L) (g/L) (g/L) gravity El Salado N.D. － 13.5 3.7 25.2 N.D. 75.8 0.22 1.1064 Japan 2.8 38.0 9.4 4.2 16.1 － 77.0 －－

Table 4-8 Chemical Composition of the Actual Ovalle Solution (The another Ovalle sample taken two months ago and preserved at the laboratory) Fe2+ T-Fe Cu Mn Zn Sn Al Cd Item pH (g/L) (g/L) (g/L) (g/L) (g/L) (mg/L) (g/L) (mg/L) El Salado 3.3 25.93 26.95 0.30 －－－－ 0.2

Pb As Ca Mg Cr F- SO 2- Cl- Specific Item 4 (mg/L) (mg/L) (mg/L) (g/L) (mg/L) (mg/L) (g/L) (g/L) Gravity El Salado N.D. － 11.4 4.5 － N.D. 74.95 0.37 －

4-7 b) Alkali consumption for neutralization of actual waste solution Alkali consumption was measured on actual solution with NaOH standard solution. Consumption for non-oxidized and oxidized solution are comparatively shown in Table 4-9 and 4-10. Based on these values, addition of alkaline reagents such as calcium carbonate and slaked lime, were determined Table 4-9 Basic Tests (1) – Alkali Consumption of Non Oxidized Solution (solution as it is) pH 3.7 4.0 5.8 6.0 6.5 7.0 7.5

Alkali consumption 0 0.2 0.42 0.45 0.525 0.675 0.83 (Equivalent)

pH 8.0 8.3 8.5 9.0 10.0 10.5 11.0

Alkali consumption 1.025 1.07 1.1 1.14 1.28 1.4 1.45 (Equivalent)

Table 4-10 Basic Tests (1) – Alkali Consumption of Oxidized Solution pH 1.9 2.0 2.5 3.0 3.3 3.5 4.0 4.5

Alkali consumption 0 0.05 0.38 0.531 0.61 0.67 0.81 0.87 (Equivalent)

pH 5.0 6.0 7.0 8.0 9.0 10.0 10.5 11.0

Alkali consumption 0.91 0.975 1.055 1.17 1.365 1.41 1.445 1.5 (Equivalent)

② Neutralization and filtering tests Neutralization tests were carried out as follows with the bench unit, before-mentioned.

4-8

Feed solution

Oxidizing reagent (H2O2)

Oxidation

Calcium carbonate (pH=3~4)

Neutralization with calcium carbonate (Confirming addition, required time and sediment volume)

Filter

Sediment Filtrate

Slake lime (pH8~10)

Neutralization with slake lime (Confirming addition, required time and sediment volume)

Filter

Sediment Filtrate

Figure 4-3 Basic Tests (1) - Flow of Neutralization Tests

4-9 a) Neutralization with calcium carbonate From the test results, following data were employed in the design of neutralization circuit of the model plant. Table 4-11 Basic Tests (1) – Results of Neutralization Tests with Calcium Carbonate Item Results 3.0 (because of less consumption of calcium pH after neutralization carbonate and possible higher recovery of copper) calcium carbonate addition 32.9g/L neutralization time 120 minutes volume of sediment 100g/L (100v/v%) moisture content in filtered cake 60%

b) Neutralization with slaked lime (after neutralized with carbonate) Further neutralization tests were carried out on the filtrate solution of the above tests with calcium carbonate. ⅰ) Solution quality after (oxidation – neutralization) with calcium carbonate Solution quality after (oxidation – neutralization) with calcium carbonate at pH 3 is shown in Table 4-12. Table 4-12 Basic Tests (1)-Solution Quality after (Oxidation – Neutralization) with Calcium Carbonate T-Fe Cu Al As Cd Mn Pb Zn Item pH (g/L) (mg/L) (g/L) (mg/L) (mg/L) (g/L) (mg/L) (g/L) at El Salado 3.4 1.71 61.6 4.05 - 0.28 0.95 - 0.219 in Japan - 2.28 62.2 3.04 0.51 0.64 1.11 0.8 0.221 ⅱ) Alkali consumption for neutralization of solution after oxidation – neutralization with calcium carbonate Alkali consumption for neutralization of solution after oxidation – neutralization with calcium carbonate is shown in Table 4-13. Table 4-13 Basic Tests (1) - Alkali Consumption for Neutralization of Solution after Oxidation – Neutralization with Calcium Carbonate Filtrate (pH was adjusted at 3.0) pH 3.1 4.0 6.0 7.0 8.0 9.0 10.0 11.0 Alkali consumption 0 0.145 0.345 0.366 0.41 0.61 0.71 0.74 (Equivalent) ⅲ) Results From these test results, the following data were employed in the design of the model plant. Table 4-14 Basic Tests (1) - Results of Neutralization Tests with Slaked Lime Item Results pH after neutralization 9.0 slaked lime addition 35.24g/L neutralization time 60 minutes volume of sediment 82.05g/L moisture content in filtered cake 60%

4-10 ③ Amount of neutralizer in each treatment process To compare the neutralization results after bacteria oxidation with those of non oxidation, the Ovalle waste solution was directly neutralized in a single step. As shown in Table 4-15, it is inevitable to raise pH above 9.0 to remove Fe from the solution. Required addition of slaked lime reached 67.75g/L, which was about 1.61 equivalent of alkali reagent from the neutralization curve of the solution. Table 4-15 Basic Tests (1) - Direct Neutralization Results of Ovalle Solution with Slaked Lime End pH 8.0 9.0 10.0 Slaked lime addition 37.925g/L 42.18g/L 47.36g/L (theoretical) Slaked lime addition 54.9g/L 67.75g/L 76.7g/L (actual) (1.45 equivalent) (1.61 equivalent) (1.62 equivalent) Method of addition powder powder powder Neutralization time 60 minutes 60 minutes 60 minutes End pH (measured) 8.0 9.3 10.1 T-Fe 1.15g/L N.D. N.D. Mn 160mg/L 4.6mg/L N.D. Quality of Zn －－－ neutralized solution Cd －－－ Pb －－－ Al N.D. N.D. N.D. Volume of sediment 100v/v% 100v/v% 100v/v%

From the above test results required amount of neutralizer is compared between oxidation-calcium carbonate-lime neutralization and direct lime neutralization. As can be seen in Table 4-16, neutralization cost is much cheaper in the former, oxidation-calcium carbonate-lime neutralization process.

Table 4-16 Basic Tests (1) - Comparison of Required Neutralizer Required neutralizer Treatment process Calcium Reagent cost Slaked lime carbonate Oxidation-calcium 32.9kg/m3 35.24kg/m3 US$2.27/m3 carbonate-lime neutralization Direct lime neutralization － 67.75kg/m3 US$6.33/m3 Unit prices of neutralizer Calcium carbonate = US$0.0589/kg Slaked lime = US$0.0935/kg

4-11 ④ Flocculation and settling tests In the model plant operation neutralized sediment shall be directly filtered with a filter press. Thus, laboratory flocculating and settling tests were carried out with bacteria carrier only, which necessitates solid-liquid separation. a) Preliminary tests As a flocculent No.9873, No.9602 (both made by NALCO CO.) and A-95 (made by Mitsui CYTEC CO., Japan) were comparatively tested. Each reagent was dissolved to 1g/L of dilution and added to carrier solution with three levels of concentration, 1g/L, 3g/L and 5g/L respectively. Among these, A-95 was the most effective as a flocculent and was decided to use in the continuous oxidation tests with the bench unit. This reagent is not available in Chile at that moment, so its equivalent or alternative (A-100 made by CYTEC CO.) had to be surveyed by the Chilean side before the start-up of the model plant. A-95 also showed the best flocculating condition than the others, followed by No.9873 and then No. 9602. b) Principal tests A-95, No.9873 and Betz Dearborn F-18 (gel) were comparatively tested. The results are shown in Table 4-17. Table 4-17 Basic Tests (1) - Results of Comparative Tests SS concentration (mg/L) in superficial water at settling velocity of 1m/h Type of Flocculent addition flocculent 1mg/L 2mg/L 3mg/L 5mg/L 10mg/L A-95 2.7 2.0 1.7 －－ impossible to impossible to impossible to impossible impossible 9873 measure measure measure to measure to measure F-18 －－ 6.1 4.7 2.3

No.9873 is ineffective to obtain clear superficial water, while A-95 shows better results even at lower concentration. F-18, which was obtained after the preliminary tests, also shows better results. These tests were carried out with the bacteria carrier formed in the laboratory oxidation tests but in the model plant operation it is not yet certain whether similar results would be obtained because higher level of salts are contained in actual Ovalle waste solutiont. At the start-up of the model plant several types of flocculent will be available to find the most suitable one for the operation.

Reference 1) Silverman, M. P. and Lundgren, D. G. : J. Bacteriol., vol.77, p.642-647, (1959) 2) Kawarasaki, T. and Yamaguchi, M. : Report of the Fermentation Research Institute, vol.72, No.9, p.55-59, (1989) 3) Yamanaka Tateo : Biseibutsu no energy taisya，Gakkai syuppan center，(1986)

4-12 4.1.2 Basic Laboratory Tests (2) Basic tests (2) includes continuous oxidation tests with help of bacteria, which were carried out in Japan to trace the basic tests (1).

(1) Purpose Main purpose is to know the change of oxidation rate when various bacteria strains are employed in the course of iron oxidation. In the basic tests (1), the Ovalle strain, adapted itself to the environment, was exclusively used. But the result obtained was 0.55g/L/h, a little lower than expected. On the other hand, an information was obtained from a Chilean counterpart that higher rate was attained formerly at El Salado laboratory with Andacollo strain in continuous oxidation of high concentration of ferrous iron. Accordingly, comparative tests were planned with Ovalle and Andacollo strains under the same test conditions. Based on the results from these tests, bacteria strain was to be selected for use at the model plant start-up.

(2) Method 1) Iron oxidizing bacteria The following three types were employed. ① Ovalle strain The strain tested in the basic tests (1) was cultivated collectively on 9K medium. ② Andacollo strain The strain, preserved in the bio-chemical laboratory of El Salado, was brought to Japan and cultivated on 9K medium. ③ Mixed strain of Ovalle and Andacollo Both strains were mixed and cultured in the bio-chemical laboratory for a long term preservation by repeated cultivation. The mixed strain was brought to Japan and cultured on 9K medium. 2) Test apparatus The apparatus is composed of an oxidation tank (volume 3.6L) and a settling tank (6.4L) in one piece. This apparatus has been used many times for quantitative comparison tests of bacteria. This time three lines of this apparatus were prepared. Working capacity of the oxidation tank was estimated at 90% of actual volume , that is, 3.6L×0.9= 3.24L, because hold-up by air as well as volume of bacteria carrier are assumed to be 10% in total. 3) Test conditions ① Quality of feed solution The following feed solution, similar to the actual Ovalle waste and also similar to the feed solution of the basic tests (1), was prepared with use of sulfate reagents. ② Test conditions Continuous tests were carried out as follows.

4-13 Table 4-18 Basic Tests (2) - Quality of Feed Solution 2+ 2- Item pH Fe T-Fe Cu Mn Zn Al Mg SO4 Quality 3 25g/L 25g/L 70mg/L 1.0g/L 200mg/L 4.0g/L 4.0g/L 80g/L

Table 4-19 Basic Tests (2) - Test Conditions Test item Condition Volume of feed solution 0.9mL/min 1.35mL/min 1.8mL/min Retention time in oxidation 60h 40h 30h tank Volume of airblow 0.45m3/m2(Oxidation tank)/min

Addition of nutrient 5mg/L of (NH4)3PO4･3H2O

(3) Results Oxidation rate of ferrous ion (Fe2+) for each bacteria strain is illustrated in Figure 4-4, and in Figure 4-5, concentration of ferrous ion remained in the solution is shown comparatively for each strain. Feed volume was adjusted to stay 60 hours in the oxidation tank up to 264 hours since start of test run, 40 hours between 288 - 600 hours of test run and 30 hours between 624 - 864 hours respectively. As can be seen from the Figure 4-5, when the retention time in the tank is 30 hours (test period is over 624 hours), ferrous ion remains not oxidized in the solution of each strain tested. Accordingly, oxidation rates are to be properly evaluated under the condition that the retention time is 30 hours in the oxidation tank. Thus, oxidation rate for each strain can be seen as 0.45g/L/h for Ovalle, and 0.65g/L/h for Andacollo and the mixed strain as well. Andacollo strain is confirmed better in oxidation ability than Ovalle. The mixed strain was somewhat worse than Andacollo alone in response, however, the both showed nearly the similar response as time passes. The oxidation in the basic tests (1) was carried out with the bench unit of the biochemical laboratory at El Salado. By these tests the oxidation rate of 0.55g/L/h was obtained. Oxidation of ferrous ions by bacteria is performed in the way that the ions are oxidized by air promoted with bacteria involvement as a sort of catalyst. Thus, the results may depend upon the shape of the apparatus (depth of solution, dispersion of air bubble etc.) used in the tests. From the basic test results (1) and (2), it is assumed that a coefficient of apparatus based upon the difference in test apparatus, is (0.55/0.45) = 1.22. Applying the coefficient to the test results (2), the oxidation rate would be 0.65 × 1.22 = 0.8 g/L/h if Andacollo strains were employed in the bench unit of El Salado. In case of the model plant, growth conditions for the iron oxidizing bacteria would be more favored because of larger oxidation capacity. It is expected that the oxidation rate will come close to the target, 1g/L/h, considering the above coefficient of apparatus. As the result, Andacollo strain was employed as iron oxidizing bacteria at start-up of the model plant.

4-14

1.0

) 0.9 h / L / 0.8 g (

e 0.7 t

a 0.6 on R i

t 0.5 a d i

x 0.4

O 0.3 ous r r 0.2

e F 0.1 0.0 0 100 200 300 400 500 600 700 800 900 Test Time （ｈ）

Ovalle strain Andacollo strain Ovalle+Andacollo strain

Figure 4-4 Change in Oxidation Rate of Fe2+

）

L 25 g/ （ n 20 o i t a r t n 15 e onc

C 10 ous r r e 5 F

0 100 200 300 400 500 600 700 800 900 Test Time （ｈ）

Feed solution Ovalle strain Andacollo strain Ovalle+Andacollo strain Figure 4-5 Change in Fe2+ Concentration

4-15 4.2 Installation and Outline of the Model Plant

4.2.1 Progress of Installation of the Model Plant Based on the S/W, signed in June, 1999 between JICA and ENAMI, the Japanese side had been in charge of plant design, procurement of machinery and equipment, marine transportation and dispatch of supervising members for the installation, while the Chilean side carried out inland transportation, civil and building works and installation of equipment. The plant was completed in early September, 2001 as scheduled and then, demonstration test run was started under the collaboration of the both sides. Outline of the plant is described in the following section. 4.2.2 Outline of the Plant (1) Process Flow During the first Study period, two types of process flow (plan A and B, described in the Progress Report) were discussed between the Japanese Study Team and ENAMI. As the result, plan B that includes pH adjustment step after neutralization was finally adopted to avoid concentrating heavy metals other than Fe. Flow diagram of the plan B is shown below.

Waste water from the Cu precipitation plant

Waste water receiver tank

Oxidation tank Nutrient

Flocculation tank Flocculent

Bacteria collector

Neutralization tank Calcium carbonate

Filter press

Filtrate tank pH adjusting tank Slaked lime

Treated water storage tank

To Leaching plant

Figure 4-6 Process Flow of the Model Plant

4-16 (2) Bases of Design Bases of design are described below. 1) Quality of waste solution from the leaching plant Quality of waste solution that is fed to the model plant was fixed as follows by mutual agreement. Table 4-20 Specification of Waste Solution to be Treated (g/L)

pH Fe2+ T-Fe Cu Mn Zn Al

3.7 30 30 0.26 0.97 0.24 9.7 2) Capacity of the model plant Treatment capacity of the model plant was set at 100m3/day by mutual agreement. 3) Oxidizing rate The plant was designed with 1.0g/L/h of oxidizing rate for Fe2+. The oxidizing rate obtained from the basic laboratory tests was 0.55g/L/h. However, oxidation with help of bacteria is generally forwarded and stabilized with larger tank capacity and under continuous operation run. Accordingly, during the plant scale operation, higher oxidizing rate is expected than 0.55g/L/h obtained from the laboratory. Thus, 1.0g/L/h, generally adopted in Japanese waste water treatment projects, was finally employed for the model plant design. 4) Volume of neutralization sediment In the laboratory tests, volume of sediment produced from the neutralization was 100g/L. In the plant design, volume of 101g/L was employed considering the difference of solution quality. 5) Volume of sediment from pH adjusting step This volume was fixed at 82.05g/L from the laboratory test results. (3) Specification of Equipment Specification of equipment was decided based on the above factors as shown in Table 4-21. (4) Installation Site This model plant was installed close to the existing Cu precipitation plant by mutual agreement. This site is convenient for the reception of waste solution from the plant and has plenty of space to construct a large-scale treatment plant later on. Layout of the model plant is shown in Figure 4-7. (5) Automatic Operation Because this model plant is not started or stopped so frequently, automatic operation systems are limited within an individual step or some interlocked machinery and instruments. Operation is fundamentally controlled inside the control room near the plant but manual handling is also available for individual machinery with use of control panels on site.

4-17 Table 4-21 Specification of Equipment

ITEM No. Equipment NameQ'ty Specification of Equipment Power(kw) Attached instrument Apparatus Type： Vertical cylinder with internal baffle pH sensor T2 3 Capacity： 57.3m3 Oxidation tank Material： FRP Dimension： 3750φ×5900H Type： Thickener 0.75 T4 1Dimension： 3300φ×2500H Bacteria collector Material： FRP Accessories： Rake Type： Roots blower 37 Rotor meter B1 1 Capacity： 14.85m3/min×7000mmAq 0.2 Inverter Oxidation blower Material： FC etc.

Type： Centrifugal pump 1.5 P2Bacterial-sludge return 1Capacity： 50L/min×20mH pump Material： Contact surface with solution FC+R/L Type： Centrifugal pump 22 P3 1Capacity： 1200L/min×40mH Bacterial-sludge feed pump Material： Contact surface with solution FC+R/L Type： Metering pump 0.2 P4 1Capacity： 450mL/min Nutrient addition pump Material： Contact surface with solution PVC,PTFE Type： Metering pump 0.2 P5 1Capacity： 850mL/min Flocculant addition pump Material： Contact surface with solution PVC,PTFE Type： Vertical cylinder with internal baffle pH sensor T11 1 Capacity： 9.5m3 Neutralization tank Material： FRP Dimension： 1650φ×5150H Type： Screw feeder 1.5 Level sensor F1 1Capacity： 825kg/h 0.75 Neutralizer feeder Material： SS Accessories： Air blaster，Bag filter Type： Vertical cylinder with internal baffle Level switch T12 1 Capacity： 0.82m3 Neutralizer re-pulping tank Material： FRP Dimension： 900φ×1600H Accessories： Agitator Type： Centrifugal pump 1.5 P7 1Capacity： 50L/min×20mH Neutralizer pump Material： Contact surface with solution FC+R/L Type： Roots blower 3.7 Flow meter B2 1 Capacity： 1.0m3/min×6000mmAq Inverter Neutralization blower Material： FC etc.

4-18 Table 4-21 Specification of Equipment

ITEM No. Equipment NameQ'ty Specification of Equipment Power(kw) Attached instrument Apparatus Type： Vertical cylinder with internal baffle Level switch T13 1 Capacity： 17.3m3 Slurry storage tank Material： FRP Dimension： 2800φ×3400H Accessories： Agitator Type： Centrifugal pump 22 P8Neutralizing-sludge feed 1Capacity： 1200L/min×40mH pump Material： Contact surface with solution FC+R/L Type： Automatic type 5.5 FP1 1Capacity： Filtration area 203㎡ Filter press Material： Filterplate PP，Bed FC+R/L Dripping pan SUS316 Type： Vertical cylinder Level switch T14 1 Capacity： 8m3 Filtrate tank Material： PE

Type： Centrifugal pump 2.2 P10Transportation pump after 1Capacity： 100L/min×20mH neutralization Material： Contact surface with solution SUS316,SCS14 Type： Vertical cylinder with internal baffle pH sensor T16 1 Capacity： 2.6m3 Level switch pH adjusting tank Material： FRP Dimension： 1500φ×2000H Accessories： Agitator Type： Screw feeder 0.4 Level sensor F2 1Capacity： 176kg/h 0.75 Lime feeder Material： SS Accessories： Air blaster，Bag filter Type： Vertical cylinder with internal baffle Level switch T17 1 Capacity： 0.82m3 Lime re-pulping tank Material： FRP Dimension： 900φ×1600H Accessories： Agitator Type： Centrifugal pump 1.5 P12 1Capacity： 50L/min×20mH Lime pump Material： Contact surface with solution FC+R/L Type： Centrifugal pump 11 P13 1Capacity： 300L/min×40mH Feed pump Material： Contact surface with solution FC+R/L Type： Vertical cylinder Level switch T18 1 Capacity： 6m3 Treated water storage tank Material： PE

Type： Centrifugal pump 2.2 P14 1Capacity： 75L/min×40mH Treated water return pump Material： Contact surface with solution SUS316,SCS14

4-19

4.3 Results of Demonstration Tests

Demonstration test run is still under way at Ovalle model plant. The results obtained for the first seven months since start-up of the plant are analyzed and summarized as follows. Detailed data are individually shown in the attached Tables at the end of this section.

4.3.1 Purpose The comprehensive purpose is to obtain necessary data for performing the feasibility study (F/S) on a large-scale waste solution treatment plant at Ovalle as well as for making the Master Plan to apply this technology to other industrial sites in Chile.

4.3.2 Test Conditions Each test item is modified along the following viewpoints. Table 4-22 Viewpoints for Modifying Test Conditions Test condition Viewpoints ・ Aimed at 100m3/day Volume of feed ・ Volume is gradually increased, as far as favorable bacteria oxidation is solution observed. Volume of bacteria ・ Quarter volume of feed solution. When feed volume is 100m3/day, sludge sludge will be 25m3/day. ・ Addition is gradually reduced (economically) observing favorable Addition of nutrient oxidation result. ・ Addition range : 0～10mg/L ・ Addition is gradually reduced (economically) observing favorable Addition of high oxidation result. molecular flocculent ・ Addition range : 5～10mg/L Neutralization pH ・ Removing Fe, while as much Cu remain dissolved. with calcium ・ Desirable to be returned to Cu leaching step for reuse. carbonate ・ pH range : 3～4 Neutralization pH ・ Removing other metals than Fe. with slaked lime ・ pH range : 8～10

4-21 4.3.3 Test Results (1) Quality of Feed Solution Quality varies considerably as shown in Table 4-23, of which analyses were carried out either in Japan or in Chile. Table 4-23 Analytical Results of Feed Solution (periodical) Fe2+ T-Fe Cu Mn Zn Al Cd Pb As Mg Date pH note (g/L) (g/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) 9/6 3.5 12.31 24.00 81 305 162 1996 - - - 3080 Chile 9/12 3.7 11.75 16.15 56 251 106 2240 0.83 0.80 - 2696 Chile 9/18 - - 15.06 102 837 269 3246 2.71 1.30 30.0 3790 Japan 9/20 3.3 20.42 28.80 253 704 298 3174 2.90 0.96 - 3807 Chile 9/25 - - 14.40 146 408 191 2861 1.45 1.00 16.0 3750 Japan 9/26 2.9 12.87 - 111 377 185 2557 1.69 N.D. - - Chile 10/3 - - 13.50 85 291 122 2160 0.78 1.00 9.0 2590 Japan - 10.62 16.95 28 321 122 1580 1.40 0.22 9.7 - Chile 10/4 - - 13.00 38 270 116 1588 0.78 0.88 7.0 2620 Japan 10/10 3.6 21.82 21.90 152 699 269 3310 1.66 0.90 27.3 - Chile 10/16 3.0 19.58 35.30 81 517 175 4949 1.19 0.43 20.8 - Chile 10/24 3.5 17.70 19.40 77 556 484 3580 1.73 0.79 - - Chile Av. - - - 101 466 208 2770 1.56 0.75 17.1 3190 － Max. - - - 253 837 484 4949 2.90 1.30 30.0 3807 － Min. - - - 28 251 106 1588 0.78 N.D. 7.0 2590 －

Figure 4-8 shows fluctuation of ferrous (Fe2+) and total iron (T-Fe). Fe2+ concentration varies between 8～33g/L but never remained at higher level for several days. As retention time in the oxidation tanks is about 30 hours, solution quality could be averaged fairly well. The average concentration of iron is shown in Table 4-24.

Table 4-24 Quality of Waste Solution (daily analyses, Sept. 6, 2001～March 31, 2002) Fe2+ T-Fe Item pH (g/L) (g/L) Minimum 3.8 7.90 8.29 Maximum 2.6 32.93 40.60 Average 3.3 17.02 20.66

4-22

) L

/ 30

g n ( o i

t 25 a r t n

e 20

onc C e 15 F

0 0 20 40 60 80 100 120 140 160 180 200 220 Test Days

Ferrous Concentration Ferric Concentration

Figure 4-8 Fe2+ and T-Fe Concentration of Feed Solution

(2) Oxidation with Help of Bacteria Change in Fe2+ concentration throughout the oxidation circuit is illustrated in Figure 4-9. As can be seen from the Table, Fe2+ remains at the outlet of the oxidation tank A but is scarcely seen at the outlet of tank B. This means two tanks are enough for oxidation of Fe2+ when treating 100m3 of the solution per day. In other words, with three oxidation tanks 150m3 of the solution can be possibly treated. Because Fe2+ is scarcely seen at the outlet of tank B, oxidation might have completed within the tank. Study is made on Figure 4-10, which shows the oxidation rate of Fe2+ in each tank against time passage. The rate is higher in the tank A, where Fe2+ is enough supplied, while lower in the C, Fe2+ is hardly supplied. Between the tank A and B, tank A shows higher rate and this suggests that the oxidation might be completed within the tank B. The oxidation rate in the tank A is around 1g/L/h, which was the original target in the plant design. Now that it is cleared and recent Fe2+ concentration in the feed is much lower (17g/L) than originally designed (30g/L), it is possible for the current circuit to treat the solution volume as estimated below unless Fe2+ concentration is sharply increased. (30/17)×100m3/day = 176m3/day

4-23

) L 25 / g n ( o i t a 20 r t n e onc 15

C ous r r e

F 10

0 0 20 40 60 80 100 120 140 160 180 200 220 Test Days

Feed Solution Tank A Tank B Tank C Oxidized Solution

Figure 4-9 Fe2+ Concentration of the Oxidation Circuit

2 1.9 1.8 1.7 1.6

) 1.5 h

L 1.4 / g (

1.3 e t a 1.2 1.1 on R i t 1 a d

i 0.9 x 0.8 O 0.7 ous r r 0.6 e

F 0.5 0.4 0.3 0.2 0.1 0 0 20 40 60 80 100 120 140 160 180 200 220 Test Days

Tank A Oxidation Rate Tank B Oxidation Rate Tank C Oxidation Rate

Figure 4-10 The Oxidation Rate of Fe2+ in each Oxidation Tank

4-24 (3) Consumption of Reagents Consumption (required amount) of each reagent is summarized as below. 1) Nutrient Addition was reduced down to 2.5mg/L for economic operation from initial 10mg/L. 2) High molecular flocculent Addition was reduced down to 5mg/L for economic operation from initial 10mg/L. Further, high-priced flocculent could be replaced by a lower one obtaining for similar result. 3) Calcium carbonate Actual consumption is shown in Table 4-25. Unit consumption is about 17g/L. Table 4-25 Actual Consumption of Calcium Carbonate on Demonstration Tests Consumption of Addition of Study Time Treated Volume CaCO3 CaCO3 Sep. 2001 1600m3 28t 17.5g/L Oct. 2001 2390m3 47t 19.7g/L Nov. 2001 2740m3 49t 17.9g/L Dec. 2001 2870m3 42t 14.6g/L Jan. 2002 2820m3 46t 16.3g/L Feb. 2002 2470m3 39t 15.8g/L Mar. 2002 2810m3 Average - - 16.9g/L 4) Slaked lime Actual consumption is shown in Table 4-26. Unit consumption is about 12g/L. Table 4-26 Actual Consumption of Slaked Lime on Demonstration Tests Consumption of Addition of Study Time Treated Volume Ca(OH)2 Ca(OH)2 Sep. 2001 120m3 2500kg 20.8g/L Oct. 2001 196m3 2000kg 10.2g/L Nov. 2001 162m3 1500kg 9.3g/L Dec. 2001 100m3 1000kg 10.0g/L Jan. 2002 116m3 1500kg 12.9g/L Feb. 2002 94m3 1000kg 10.6g/L Mar. 2002 98m3 Average - - 12.1g/L 5) Reagent costs Total reagent costs are estimated as shown in Table 4-27. Table 4-27 Estimated Reagent Cost (Treated Volume 100m3/day) Reagents Addition and Consumption Cost 3 3 CaCO3 17kg/m × 100m /day = 1700kg/day US$0.0589/kg US$100.13/day 3 3 Ca(OH)2 12kg/m × 10m /day = 120kg/day US$0.0935/kg US$11.22/day Nutrient 2.5g/m3 × 100m3/day = 250g/day US$4.61/kg US$1.15/day Flocculent 5g/m3 × (100＋25)m3/day = 625g/day US$4.248/kg US$2.66/day Total (Feed Solution 100m3/day) US$115.16/day

4-25 (4) Volume of Sediment Volume of total sediment (m3/day or t-wet/day), moisture content of filtered cake and volume of sediment from neutralization with calcium carbonate are illustrated below with mutual correlation. When feed solution volume is 100m3/day, 8.5m3 or 12.5t-wet of sediment are produced from entire circuit of the plant as shown in Figure 4-11 and 4-12. Average T-Fe concentration in the oxidized solution, feed to neutralization step, was 11.7g/L throughout the test period. From Figure 4-14, corresponding volume of carbonate sediment is seen as 60.5g-dry/L. Thus, when volume of feed solution is 100m3/day, 6.05t-dry/day of the sediment is produced. Moisture content of filtered cake is seen from Figure 4-13 as 47.5%. Then, wet volume should be 6.05÷(1-0.475) = 11.5t-wet/day. Sediments produced from the model plant are neutralized one with calcium carbonate and slaked lime respectively as well as excess bacteria sludge. When feed solution volume is 100m3/day, total volume of sediments amounts to 12.5t-wet/day, of which neutralized with carbonate is 11.5t-wet/day. That is, the difference of 1.0t-wet/day is produced as sediment with lime and bacteria sludge.

20.0

18.0

16.0

)

y 14.0 a /d 3

m 12.0 ( s t

uc 10.0 od r P t

n 8.0 e m di e

S 6.0 y = 0.0854x

4.0

2.0 0.0 0 102030405060708090100110120 3 Feed Solution (m /day)

Figure 4-11 Total Sediment Volume (m3/day) vs. Feed Solution

4-26

30.0

28.0

26.0 24.0

) 22.0 y a d

t 20.0 e w

- 18.0

t ( s t 16.0 duc

o 14.0 r P 12.0 nt e m 10.0 di e

S 8.0 y = 0.1246x 6.0

4.0

2.0 0.0 0 102030405060708090100110120

Feed Solution (m3/day)

Figure 4-12 Total Sediment Volume (t-dry/day) vs. Feed Solution

) 60 % /w w

( e

k 50 a

C s s e r

P 40 r e t

l i F

t of 30 n e

t n o

e 20 r tu

s i o

M 10

0 0 20 40 60 80 100 120 140 160 180 200 220 Test Days

Figure 4-13 Change of Moisture Content in Filtered Cake

4-27

160

140

) L /

ry 120 y = 5.1726x -d

(g 3

O 100 C

a C

h t

w 80 s

t uc

od r 60 P t

n e m 40 di e S 20

0 0 5 10 15 20 25 Total Fe Concentration in the Oxidized Solution (g/L)

Figure 4-14 Sediment with Calcium Carbonate vs. T-Fe in Oxidized Solution

(5) Grade of Sediment Each sediment was chemically analyzed in a laboratory of Japan. The results are shown in Table 4-28. Table 4-28 Grade of Individual Sediment Sediment with Sediment with Sediment Bacteria Sludge Filtered Cake Carbonate Lime Fe (%) 40.3 16.8 0.25 15.7 Cu (mg/kg) 62.7 271 1320 319 Mn (mg/kg) 143 560 10700 370 Zn (mg/kg) 42.5 146 2140 106 Al (mg/kg) 1060 13900 34100 10600 As (mg/kg) 386 50.5 16.8 43.7 Ca (%) 2.36 15.9 21.2 19.0 SO4 (%) 22.9 44.0 44.0 47.1 The bacteria sludge is mainly composed of basic iron sulfate containing about 2% of Ca and 0.1% of Al. Content of other metals than Fe is lower. Arsenic is contained by around 0.04% and this brings difficulty for effective utilization of the sludge. Neutralization sediment with calcium carbonate is a mixture of gypsum and iron sediment. Sediment with slaked lime is a mixture of oxides of Mn, Al, Cu, Zn etc. and gypsum. For recovery of iron metal, an intermediate sediment between the sludge and sediment with calcium carbonate would be suitable. Any neutralizing condition should be searched, which will not allow arsenic and gypsum to coexist.

4-28 (6) Leaching Tests on Oxide Ore with Use of Treated Solution from the Model Plant Leaching tests were carried out by Chilean counterparts with treated (oxidized) solution from the model plant. 1) Test results with treated solution (effluent) from the model plant Test conditions and results are shown in the Table 4-29 and Figure 4-15 respectively. Leaching with industrial water, usually employed in the operation, was also carried out for comparison of the results. Waste rocks from the primary leaching step in the plant were also examined along with fresh crude ores. The results show no negative effect on Cu leaching recovery if the treated solution was used as solvent. In case of crude ore leaching, the treated solution gave better results than industrial water solvent. Supposedly this was caused by effectiveness of ferric iron and recovery of remaining Cu. Table 4-29 Leaching Test Conditions with Treated Solution Column No. Solute Solvent Waste rocks from primary 1 Industrial water + 30g/L of H SO leaching 2 4 Waste rocks from primary Treated solution from the model plant + 30g/L 2 leaching of H2SO4 3 Fresh crude ores Industrial water + 45g/L of H2SO4 Treated solution from the model plant + 45g/L 4 Fresh crude ores of H2SO4

100 90

(%) 80

e 70 l b u l 60 o 50 of S o i t 40 Ra

ng 30 hi c

a 20 e

L 10 0 0 5 10 15 20 25 30 35 Test Days

2nd Ore+H2SO4=30g/L 2nd Ore+Treated Solution+H2SO4=30g/L Ore+H2SO4=45g/L Ore+Treated Solution+H2SO4=45g/L

Figure 4-15 Test Results with Treated Solution

4-29 2) Test Results with Oxidized Solution from the Model Plant Test conditions and results are shown in Table 4-30 and Figure 4-16 respectively. Ferric ion is effective for oxidation, however, could hinder dissolution of Cu if the concentration is too high in solvent. Suitable level of Fe3+ clearly promoted Cu dissolution. Table 4-30 Leaching Test Conditions with Oxidized Solution Column No. Solute Solvent Waste rocks from primary 1 Industrial water + 10g/L of H SO leaching 2 4 Waste rocks from primary Industrial water + 10g/L of H SO and + 2 2 4 leaching 1.8v/v% oxidized solution from the model plant Waste rocks from primary Industrial water + 10g/L of H SO and + 3 2 4 leaching 36v/v% oxidized solution from the model plant Waste rocks from primary Industrial water + 10g/L of H SO and + 4 2 4 leaching 60v/v% oxidized solution from the model plant Waste rocks from primary Oxidized solution from the model plant + 10g/L 5 leaching of H2SO4

100 90 (%) 80 Cu

e l 70 b u l

o 60 50

of S o i t 40 Ra 30 ng

c 20 a e

L 10 0 12345678910

Test Days

H2SO4=10g/L Oxidized Solution=1.8v/v%+H2SO4=10g/L Oxidized Solution=36v/v%+H2SO4=10g/L Oxidized Solution=60v/v%+H2SO4=10g/L Oxidized Solution=100v/v%+H2SO4=10g/L

Figure 4-16 Test Results with Oxidized Solution

4-30 4.3.4 Summary of the Demonstration Tests (1) Operational Conditions at the Model Plant Table 4-31 shows operational conditions, which led to the expected results. Table 4-31 Operational Conditions at the Model Plant Item Condition, Results ・ Possible to treat 100m3/day or more. Treatment volume ・ The maximum volume is supposed to a 176m3/day Volume of bacteria sludge ・Quarter volume of feed solution Addition of nutrient ・2.5mg/L to the feed solution Addition of high ・5mg/L to the feed solution molecular flocculent ・ Neutralization pH＝3.5-4 Neutralization pH with ・ calcium carbonate Average consumption of calcium carbonate is about 17g/L. Neutralization pH with ・ Neutralization pH=8-9 slaked lime ・ Average consumption of slaked lime is about 12g/L. (2) Operational Results at the Model Plant 1) Reagent cost is estimated at around US$ 115/day when 100m3 of waste solution is treated per day. 2) Leaching tests carried by the Chilean counterparts showed that the treated solution (model plant effluent) could be reused at the leaching step without any harmful effects. It was also suggested the oxidized solution (after oxidation step) would promote leaching of Cu minerals if it is mixed suitably with the original leach solvent. 3) When 100m3 of the waste solution is treated a day at the model plant, about 12.5t-wet (8.5m3) of filtered cake is produced per day. Moisture content of the cake is around 47.5%. (3) Utilization of the Model Plant from now on Following proposals are made for effective and economical utilization of the plant from the standpoint of overall Ovalle operation. However, some modifications of the plant are needed, on which Chap. 5 of this report is referred to. 1) Volume of feed solution shall be increased to the possible maximum level. 2) When 176m3 of the waste solution is treated per day, around 10.7t-dry of neutralization sediment with carbonate is produced a day. Wet volume will be about 20.4t-wet/day as 47.5% of moisture is contained. Thus, around 9.7t of water is eliminated out of the operation. This volume corresponds to more than 5% of feed solution to be daily handled. The reduction of this volume of water would prevent heavy accumulation of bacteria metabolite and other metals than Fe in the circuit. Then, neutralization with slaked lime for one tenth volume of the solution, originally designed, is not always necessary. This neutralization with lime shall be operated if necessary, when some metals like Zn and Mn are concentrated abnormally or bacteria activity is reduced. 3) As the result of leaching tests with use of oxidized solution, suitable amount of ferric sulfate promotes Cu leaching. Thus, it is not always necessary in the neutralization step of the

4-31 model plant to completely neutralize ferric ions. This also saves neutralization cost. However, if complete neutralization is required, pH shall be regulated at 4.0, for example, when clearness of solution is required first or clogging of solution pipes are feared, etc.

4.4 Present and Future of the Model Plant The following data and information were obtained during the 7th (final) field survey period. (1) Present situation Until recently, part of the pregnant (leached) solution was separately treated for recovery of

CuSO4・5H2O as a new product. However, this operation has been suspended due to some difficulty in marketing. Another important change in operation is that the excess waste solution from the Cu precipitation step, which exceeds the model plant capacity, is now sent back to the leaching step for reuse instead of evaporation treatment in the ponds. This could have brought higher concentration of Fe and other metal ions in the waste solution to be fed to the model plant. The recent data of the solution is shown in Figure 4-17. The recent operational data of the model plant are obtained as follows. ・ Total volume of the waste solution from the Cu precipitation : 220m3/day ・ Feed volume to the model plant : 50m3/day ・ Circulating volume to the leaching step : 170m3/day ・ Fe２+ concentration at the inlet of oxidation tanks : 57.3g/L ・ Fe2+ concentration at the outlet of oxidation tanks : 0.9g/L As shown above, oxidation with bacteria is satisfactorily realized, though Fe2+ concentration of the feed solution is nearly the saturation.

(2) Future Current operation cost at the model plant is around US$ 13,000～15,000/month including labor cost. It is urgent to reduce this operation cost. For this purpose, caustic soda is now being introduced as a neutralizer on a trial for calcium carbonate to recover any salable byproduct like ferric sulfate solution, free from gypsum, as an inorganic flocculent, which could be used in waste water treatment. Commercial and economic situation are yet to be studied.

4-32 ) L

/ 45 g 40 on ( i t a r 35 t n e 30 onc 25 on C r

I 20 l a t o 15

nd T 10 a 5 ous r r e 0 F 4 2 6 4 1 22 4/ 18 5/ 23 6/ 20 7/ 18 8/ 16 29 3/ 4/ 5/ 6/ 7/ 8/ 8/ Test Days (2002)

Fe2+ T-Fe

1600 )

L 1400 g/ m 1200 on ( i t a r 1000 t n e 800 onc

C 600 n 400 nd Z 200 Mn a 0 4 2 6 4 1 22 4/ 18 5/ 23 6/ 20 7/ 18 8/ 16 29 3/ 4/ 5/ 6/ 7/ 8/ 8/ Test Days (2002)

Mn Zn

9000 )

L 8000

g/ m 7000 on ( i

t 6000 a r t n 5000 e

onc 4000 3000 nd Mg C 2000 a l

A 1000

4 2 6 4 1 22 4/ 18 5/ 23 6/ 20 7/ 18 8/ 16 29 3/ 4/ 5/ 6/ 7/ 8/ 8/

Test Days (2002)

Al Mg

Figure 4-17 Recent Analytical Data of the Waste Solution

4-33 4.5 Instructing Subjects for Technology Transfer The following technical items were transferred throughout the Study period. (1) Cultivation Method of Iron Oxidizing Bacteria 1) Liquid culture 2) Plate culture 3) Subculture

(2) Counting Method of Iron Oxidizing Bacteria 1) Direct count 2) Culturing count

(3) Continuous Oxidation Tests with Use of Iron Oxidizing Bacteria 1) Mass cultivation of bacteria 2) Forming bacteria carrier 3) Test program, conditions, data collecting and analyses

(4) Neutralization Tests 1) Neutralization curve 2) Required amount of neutralizer and volume of sediment 3) Settling tests 4) Filtering tests

(5) Demonstration Tests at the Model Plant (for waste solution treatment) 1) Test conditions 2) Analytic methods 3) Data collection and analyses

4-34 Appendix 4-1 Quality of Feed and Oxidized Solution

4-35 9/12 50 49.5 10.0 0.33 9K 25.0 54.17 20.0 6.0 3.67 11.75 16.15 56 251 2696 2.66 5538 10.75 124 1974 52.9 0.13 9/13 50 49.5 10.0 0.33 9K 25.0 59.08 21.6 5.0 3.62 10.91 18.60 113 245 2197 2.49 5258 10.75 110 5997 51.8 0.11 9/14 50 59.4 10.0 0.33 9K 12.5 58.96 77.2 5.0 3.54 14.54 14.58 155 360 2486 2.39 2853 9.46 16.5 80.4 0.20 9/15 50 59.4 10.0 0.33 0 12.5 82.4 5.0 3.71 21.26 25.78 2.32 168 7.25 99.2 0.35 9/16 9/17 50 59.4 10.0 0.33 0 12.5 190.00 75.2 5.0 3.78 24.61 23.70 2.40 112 8.95 44.92 99.5 0.41 9/18 50 59.4 10.0 0.33 0 12.5 150.12 68.0 5.0 3.68 20.14 17.30 100 684 6833 2.28 84 11.34 50.78 99.6 0.34 9/19 50 59.4 10.0 0.33 0 12.5 119.68 57.6 5.0 3.37 21.26 34.80 113 775 2.31 84 19.14 122 85.3 99.6 0.36 9/20 60 49.5 5.0 0.33 0 15.0 110.24 60.8 5.0 3.29 20.42 28.80 253 704 3807 2.45 84 19.46 135 95.5 99.6 0.41 9/21 0 9/22 60 51.2 5.0 0.33 0 12.5 58.40 58.0 5.0 2.57 19.02 27.10 138 434 4310 2.40 28 20.90 137 99.9 0.37 9/23 60 51.2 5.0 0.33 0 12.5 94.76 60.0 5.0 3.00 2.20 30665 9/24 60 51.2 5.0 0.33 0 12.5 126.20 64.0 5.0 3.14 15.94 17.30 65 406 6026 2.32 28 14.20 120 2778 99.8 0.31 9/25 70 45.0 5.0 0.33 0 12.5 112.00 70.0 5.0 3.02 16.22 16.60 78 410 3610 2.25 N.D. 13.10 105 16348 100.0 0.36 9/26 70 42.5 5.0 0.33 0 17.5 112.00 72.4 5.0 2.88 12.87 7.90 111 377 2.21 28 8.50 97 1898 99.8 0.30 9/27 70 42.5 5.0 0.33 0 17.5 68.8 5.0 3.01 12.87 13.30 35 396 2.19 28 10.45 119 195 99.8 0.30 9/28 80 37.2 5.0 0.33 0 20.0 139.64 73.0 5.0 2.70 12.87 17.60 2.31 28 11.30 99.8 0.35 9/29 80 37.2 5.0 0.33 0 20.0 154.12 79.6 5.0 3.49 19.02 20.47 2.32 28 11.35 99.9 0.51 9/30 80 37.2 5.0 0.33 0 20.0 72.4 5.0 3.33 2.42 Appendix 4-1 Quality of Feed and Oxidized Solution

4-36 10/15 80 37.2 5.0 0.33 0 20.0 66.50 98.0 5.0 2.97 17.60 17.90 208 465 2.20 170 17.90 89 99.0 0.47 10/16 80 37.2 5.0 0.33 0 20.0 72.00 96.0 5.0 3.02 19.58 35.30 81 517 2.26 28 15.70 115 99.9 0.53 10/17 80 37.2 5.0 0.33 0 20.0 98.20 76.0 5.0 3.04 15.10 18.60 107 423 2.29 28 15.60 149 99.8 0.41 10/18 80 37.2 5.0 0.33 0 20.0 88.10 56.0 5.0 3.55 12.50 22.40 66 416 2.31 28 9.40 104 99.8 0.34 10/19 80 37.2 5.0 0.33 0 20.0 72.50 88.0 5.0 3.57 27.60 30.40 100 769 2.25 28 9.50 92 99.9 0.74 10/20 80 37.2 5.0 0.33 0 20.0 5.0 10/21 80 37.2 5.0 0.33 0 20.0 5.0 10/22 80 37.2 5.0 0.33 0 20.0 119.00 40.0 5.0 3.38 26.50 27.30 95 763 2.21 28 17.50 117 99.9 0.71 10/23 90 33.0 5.0 0.33 0 22.5 100.00 99.2 5.0 3.60 23.71 36.40 112 740 2.15 28 17.20 105 99.9 0.72 10/24 90 33.0 5.0 0.33 0 22.5 68.00 94.4 5.0 3.54 17.70 19.40 77 556 2.27 28 17.50 117 99.8 0.54 10/25 90 33.0 5.0 0.33 0 22.5 76.00 98.4 5.0 3.19 23.74 25.95 70 532 2.23 28 15.60 116 99.9 0.72 10/26 90 33.0 5.0 0.33 0 22.5 58.30 67.2 5.0 3.00 27.05 32.80 56 415 2.29 160 15.60 94 99.4 0.81 10/27 90 33.0 5.0 0.33 0 22.5 5.0 10/28 90 33.0 5.0 0.33 0 22.5 5.0 10/29 90 33.0 5.0 0.33 0 22.5 68.20 98.8 5.0 3.45 26.50 32.20 183 820 2.13 440 18.12 128 98.3 0.79 10/30 90 33.0 5.0 0.33 0 22.5 59.00 5.0 3.13 18.22 27.60 238 592 2.10 170 8.15 73 99.1 0.55 10/31 90 33.0 5.0 0.33 0 22.5 5.0 3.19 16.57 26.70 Appendix 4-1 Quality of Feed and Oxidized Solution

Bacteria Sludge Quality of Feed Solution Quality of Oxidized Solution Feed Ox. Time Nutrient Air H2SO4 Ox. pH Flocculent Ox. Ratio Ox. Rate Ox. Sediment Date Flow Conc. Volume pH Fe2+ T-Fe Cu Mn Mg pH Fe2+ T-Fe Cu SS m3/day h mg/L m3/m2/min g/L m3/day g/L v/v% mg/L g/L g/L mg/L mg/L mg/L mg/L g/L mg/L mg/L % g/L/h kg/day 11/1 11/2 70 42.5 5.0 0.33 9K 17.5 5.0 11/3 70 42.5 5.0 0.33 9K 17.5 5.0 11/4 70 42.5 5.0 0.33 0 17.5 5.0 11/5 70 42.5 5.0 0.33 0 17.5 5.0 11/6 80 37.2 5.0 0.33 0 20.0 48.00 5.0 3.28 24.30 26.50 127 542 2.18 28 13.13 169 99.9 0.65 11/7 80 37.2 5.0 0.33 0 20.0 5.0 3.36 17.67 19.80 114 2.20 28 12.01 126 24162 99.8 0.47 11/8 80 37.2 5.0 0.33 0 20.0 53.00 5.0 3.47 20.43 21.01 96 2.28 28 13.70 149 21770 99.9 0.55 11/9 90 33.0 5.0 0.33 0 22.5 80.70 73.0 5.0 3.26 16.57 17.73 2.08 28 12.91 12558 99.8 0.50 11/10 90 33.0 5.0 0.33 0 22.5 81.00 75.2 5.0 3.30 12.70 13.30 2.23 28 11.64 10802 99.8 0.38 11/11 90 33.0 5.0 0.33 0 22.5 5.0 11/12 90 33.0 5.0 0.33 0 22.5 74.20 62.0 5.0 3.50 24.30 25.80 2.24 110 12.16 5974 99.5 0.73 11/13 100 29.7 5.0 0.33 0 25.0 100.00 5.0 3.51 18.77 29.50 2.18 28 23.33 5269 99.9 0.63 11/14 100 29.7 5.0 0.33 0 25.0 59.80 5.0 3.27 17.67 28.57 2.28 28 22.36 50742 99.8 0.59 4-37 11/15 100 29.7 5.0 0.33 0 25.0 33.70 95.0 5.0 3.19 12.70 17.47 2.23 28 18.80 27754 99.8 0.43 11/16 100 29.7 5.0 0.33 0 25.0 41.40 99.2 5.0 3.53 23.74 27.10 2.26 28 11.20 33751 99.9 0.80 11/17 100 29.7 5.0 0.33 0 25.0 56.8 5.0 11/18 100 29.7 5.0 0.33 0 25.0 52.8 5.0 11/19 100 29.7 5.0 0.33 0 25.0 45.40 52.0 5.0 3.25 25.40 25.80 2.27 28 13.80 15737 99.9 0.85 11/20 100 29.7 5.0 0.33 0 25.0 70.30 74.4 5.0 2.73 24.85 26.72 2.30 28 15.82 8554 99.9 0.84 11/21 100 29.7 5.0 0.33 0 25.0 43.00 5.0 2.65 16.02 18.99 2.33 28 12.66 22772 99.8 0.54 11/22 100 29.7 5.0 0.33 0 25.0 47.00 7.2 5.0 3.11 14.90 16.26 2.26 28 13.00 20532 99.8 0.50 11/23 110 27.0 5.0 0.33 0 27.5 43.00 11.2 5.0 2.90 14.36 22.70 2.26 28 12.88 16600 99.8 0.53 11/24 110 27.0 5.0 0.33 0 27.5 5.0 11/25 110 27.0 5.0 0.33 0 27.5 50.60 36.0 5.0 11/26 110 27.0 5.0 0.33 0 27.5 75.30 58.0 5.0 3.29 12.50 17.90 1.82 28 9.36 1822 99.8 0.46 11/27 110 27.0 5.0 0.33 0 27.5 43.70 64.0 5.0 50 11/28 110 27.0 5.0 0.33 0 27.5 34.50 31.2 5.0 11/29 90 33.0 5.0 0.33 0 22.5 21.30 20.8 5.0 3.29 11.04 16.03 11/30 110 27.0 5.0 0.33 0 27.5 116.70 66.4 5.0 3.01 8.28 15.17 2.10 N.D. 8.82 17 100.0 0.31 Appendix 4-1 Quality of Feed and Oxidized Solution

4-38 12/15 100 29.7 5.0 0.33 0 25.0 36.0 5.0 12/16 100 29.7 5.0 0.33 0 25.0 5.0 12/17 100 29.7 5.0 0.33 0 25.0 43.00 36.0 5.0 3.60 16.57 2.09 N.D. 100.0 0.56 12/18 100 29.7 5.0 0.33 0 25.0 96.80 61.6 5.0 3.65 13.25 13.96 2.11 28 11.05 1186 99.8 0.44 12/19 100 29.7 5.0 0.33 0 25.0 97.30 61.6 5.0 3.62 11.04 12.78 2.05 28 9.50 18472 99.7 0.37 12/20 100 29.7 5.0 0.33 0 25.0 99.80 59.2 5.0 3.61 12.15 12.97 2.02 28 7.38 715 99.8 0.41 12/21 100 29.7 5.0 0.33 0 25.0 132.70 61.6 5.0 3.68 18.22 25.12 2.23 28 7.28 18219 99.8 0.61 12/22 100 29.7 5.0 0.33 0 25.0 5.0 12/23 110 27.0 5.0 0.33 0 27.5 5.0 12/24 110 27.0 5.0 0.33 0 27.5 167.00 84.0 5.0 3.47 13.25 13.26 2.00 28 9.01 99.8 0.49 12/25 110 27.0 5.0 0.33 0 27.5 71.10 73.0 5.0 12/26 5.0 0.33 0 0.0 5.0 12/27 5.0 0.33 0 0.0 71.10 54.0 5.0 12/28 5.0 0.33 0 0.0 34.20 17.0 5.0 12/29 80 37.2 5.0 0.33 0 20.0 48.90 24.0 5.0 12/30 100 29.7 5.0 0.33 0 25.0 5.0 12/31 100 29.7 5.0 0.33 0 25.0 85.60 5.0 3.45 9.40 12.77 2.34 28 9.08 176 99.7 0.32 Appendix 4-1 Quality of Feed and Oxidized Solution

4-39 1/15 100 29.7 2.5 0.33 0 25.0 238.50 48.0 5.0 3.49 23.10 23.44 1.91 28 10.38 981 99.9 0.78 1/16 100 29.7 2.5 0.33 0 25.0 313.10 60.0 5.0 3.51 17.86 24.43 1.98 28 11.42 395 99.8 0.60 1/17 100 37.2 2.5 289.00 66.0 5.0 3.46 13.30 13.96 1.92 28 10.83 503 99.8 0.36 1/18 100 29.7 2.5 0.33 0 25.0 88.90 25.2 5.0 3.49 12.82 13.39 1.95 28 10.42 781 99.8 0.43 1/19 100 29.7 2.5 0.33 0 25.0 5.0 1/20 100 29.7 2.5 0.33 0 25.0 5.0 1/21 100 29.7 2.5 0.33 0 25.0 77.90 64.0 5.0 3.26 16.19 19.82 1.90 N.D. 9.77 836 100.0 0.54 1/22 100 29.7 2.5 0.33 0 25.0 164.00 51.0 5.0 3.30 14.00 16.75 1.92 28 10.99 1004 99.8 0.47 1/23 100 29.7 2.5 0.33 0 25.0 283.00 57.0 5.0 3.23 12.52 12.84 1.90 28 9.56 673 99.8 0.42 1/24 100 29.7 2.5 0.33 0 25.0 295.00 58.0 5.0 3.04 11.72 12.52 1.87 28 8.79 496 99.8 0.39 1/25 100 29.7 2.5 0.33 0 25.0 281.00 56.0 5.0 2.90 12.28 13.06 1.88 28 8.25 884 99.8 0.41 1/26 100 29.7 2.5 0.33 0 25.0 5.0 1/27 100 29.7 2.5 0.33 0 25.0 5.0 1/28 90 33.0 2.5 0.33 0 22.5 230.00 20.0 5.0 3.26 15.07 14.38 1.95 28 10.99 99.8 0.46 1/29 90 33.0 2.5 0.33 0 22.5 190.00 52.0 5.0 3.30 12.28 14.90 1.89 28 8.64 99.8 0.37 1/30 1/31 50 59.4 2.5 0.33 0 12.5 76.60 18.4 5.0 Appendix 4-1 Quality of Feed and Oxidized Solution

Bacteria Sludge Quality of Feed Solution Quality of Oxidized Solution Feed Ox. Time Nutrient Air H2SO4 Ox. pH Flocculent Ox. Ratio Ox. Rate Ox. Sediment Date Flow Conc. Volume pH Fe2+ T-Fe Cu Mn Mg pH Fe2+ T-Fe Cu SS m3/day h mg/L m3/m2/min g/L m3/day g/L v/v% mg/L g/L g/L mg/L mg/L mg/L mg/L g/L mg/L mg/L % g/L/h kg/day 2/1 100 29.7 2.5 0.33 0 25.0 220.00 50.4 5.0 3.24 20.65 30.82 1.77 N.D. 9.18 100.0 0.69 2/2 100 29.7 2.5 0.33 0 25.0 5.0 2/3 100 29.7 2.5 0.33 0 25.0 5.0 2/4 90 33.0 2.5 0.33 0 22.5 132.60 37.6 5.0 3.11 14.51 20.58 1.68 28 10.24 99.8 0.44 2/5 100 29.7 2.5 0.33 0 25.0 244.20 66.0 5.0 3.24 11.16 11.37 1.76 28 10.62 301 99.7 0.37 2/6 100 29.7 2.5 0.33 0 25.0 210.80 62.4 5.0 3.34 13.40 13.89 1.73 N.D. 8.46 280 100.0 0.45 2/7 100 29.7 2.5 0.33 0 25.0 272.00 77.0 5.0 3.34 25.11 26.11 1.73 28 8.08 83 99.9 0.84 2/8 100 29.7 2.5 0.33 0 25.0 221.00 61.6 5.0 3.33 29.18 30.70 1.88 28 11.05 58 99.9 0.98 2/9 100 29.7 2.5 0.33 0 25.0 48.0 5.0 2/10 100 29.7 2.5 0.33 0 25.0 5.0 2/11 100 29.7 2.5 0.33 0 25.0 168.80 51.2 5.0 2.88 25.68 37.58 1.62 28 14.08 1540 99.9 0.86 2/12 100 29.7 2.5 0.33 0 25.0 303.00 72.0 5.0 2.83 18.98 28.60 1.68 28 16.19 339 99.9 0.64 2/13 100 29.7 2.5 0.33 0 25.0 283.00 78.0 5.0 2.99 15.82 16.75 2.17 28 12.30 59875 99.8 0.53 4-40 2/14 100 29.7 2.5 0.33 0 25.0 240.00 44.0 5.0 3.07 16.75 24.63 2.07 28 12.71 8297 99.8 0.56 2/15 100 29.7 2.5 0.33 0 25.0 60.0 5.0 3.16 22.89 23.00 2.07 28 10.80 7231 99.9 0.77 2/16 100 29.7 2.5 0.33 0 25.0 5.0 2/17 100 29.7 2.5 0.33 0 25.0 5.0 2/18 80 37.2 2.5 0.33 0 20.0 226.00 9.6 5.0 3.42 32.93 34.05 2.14 28 14.05 99.9 0.89 2/19 50 59.4 2.5 0.33 0 12.5 5.0 2/20 60 49.5 2.5 0.33 0 15.0 5.0 3.30 16.75 17.08 2.06 28 12.30 99.8 0.34 2/21 70 42.5 2.5 0.33 0 17.5 107.00 5.0 3.38 12.28 13.22 2.03 28 12.06 99.8 0.29 2/22 90 33.0 2.5 0.33 0 22.5 114.00 94.0 5.0 3.45 12.84 14.63 2.08 28 11.69 99.8 0.39 2/23 90 33.0 2.5 0.33 0 22.5 5.0 2/24 90 33.0 2.5 0.33 0 22.5 5.0 2/25 90 33.0 2.5 0.33 0 22.5 70.20 52.0 5.0 3.23 22.33 28.37 2.05 28 8.82 99.9 0.68 2/26 90 33.0 2.5 0.33 0 22.5 48.40 56.0 5.0 3.22 20.09 21.59 2.25 28 8.11 99.9 0.61 2/27 0 2/28 70 42.5 2.5 0.33 0 17.5 32.30 82.0 5.0 3.16 17.30 16.66 Appendix 4-1 Quality of Feed and Oxidized Solution

4-41 3/15 100 29.7 2.5 0.33 0 25.0 68.00 5.0 3.48 24.89 35.18 2.01 28 11.38 10200 99.9 0.84 3/16 100 29.7 2.5 0.33 0 25.0 74.0 5.0 3/17 100 29.7 2.5 0.33 0 25.0 66.0 5.0 3/18 100 29.7 2.5 0.33 0 25.0 31.00 59.0 5.0 3.24 13.28 18.67 1.80 28 12.51 362 99.8 0.45 3/19 100 29.7 2.5 0.33 0 25.0 54.00 76.0 5.0 3.18 11.06 11.98 1.99 28 11.24 99.7 0.37 3/20 110 27.0 2.5 0.33 0 27.5 62.00 76.0 5.0 3.22 11.06 17.93 2.00 28 9.61 13881 99.7 0.41 3/21 110 27.0 2.5 0.33 0 27.5 60.00 80.0 5.0 3.22 9.40 10.20 1.98 28 8.58 362 99.7 0.35 3/22 110 27.0 2.5 0.33 0 27.5 63.00 84.0 5.0 3.21 8.30 9.80 1.76 N.D. 7.49 178 100.0 0.31 3/23 110 27.0 2.5 0.33 0 27.5 5.0 3/24 110 27.0 2.5 0.33 0 27.5 5.0 3/25 70 42.5 2.5 0.33 0 17.5 37.00 11.0 5.0 3.69 12.72 19.66 2.42 28 6.60 258 99.8 0.30 3/26 90 33.0 2.5 0.33 0 22.5 51.00 34.0 5.0 3.52 11.06 13.56 1.88 N.D. 11.76 266 100.0 0.33 3/27 100 29.7 2.5 0.33 0 25.0 96.00 54.0 5.0 3.43 9.40 15.07 1.88 28 7.29 676 99.7 0.32 3/28 110 27.0 2.5 0.33 0 27.5 24.0 5.0 3.44 8.85 11.23 1.95 N.D. 8.13 100.0 0.33 3/29 110 27.0 2.5 0.33 0 27.5 5.0 3/30 110 27.0 2.5 0.33 0 27.5 5.0 3/31 90 33.0 2.5 0.33 0 22.5 5.0 Appendix 4-1 Quality of Feed and Oxidized Solution

Bacteria Sludge Quality of Feed Solution Quality of Oxidized Solution Feed Ox. Time Nutrient Air H2SO4 Ox. pH Flocculent Ox. Ratio Ox. Rate Ox. Sediment Date Flow Conc. Volume pH Fe2+ T-Fe Cu Mn Mg pH Fe2+ T-Fe Cu SS m3/day h mg/L m3/m2/min g/L m3/day g/L v/v% mg/L g/L g/L mg/L mg/L mg/L mg/L g/L mg/L mg/L % g/L/h kg/day 4/1 100 29.7 2.5 0.33 0 25.0 55.90 5.0 3.49 8.30 15.28 1.94 28 4.31 873 99.7 0.28 4/2 100 29.7 2.5 0.33 0 25.0 112.80 51.2 5.0 3.44 9.96 17.29 2.09 28 4.82 784 99.7 0.33 4/3 100 29.7 2.5 0.33 0 25.0 5.20 55.2 5.0 3.41 22.68 32.04 2.02 28 4.98 615 99.9 0.76 4/4 100 29.7 2.5 0.33 0 25.0 55.2 5.0 3.47 24.89 30.05 2.09 111 7.89 99.6 0.83 4/5 80 37.2 2.5 0.33 0 20.0 5.0 4/6 80 37.2 2.5 0.33 0 20.0 5.0 4/7 90 33.0 2.5 0.33 0 22.5 5.0 4/8 90 33.0 2.5 0.33 0 22.5 63.50 28.0 5.0 2.93 12.17 12.50 1.70 55 12.45 2008 99.5 0.37 4/9 90 33.0 2.5 0.33 0 22.5 175.40 58.4 5.0 2.91 10.51 10.97 1.96 55 11.02 811 99.5 0.32 4/10 110 27.0 2.5 0.33 0 27.5 198.50 5.0 2.89 9.96 10.25 2.01 55 9.65 1538 99.4 0.37 4/11 120 24.8 2.5 0.33 0 30.0 146.10 68.0 5.0 3.07 8.30 9.64 1.97 55 8.93 41981 99.3 0.33 4/12 120 24.8 2.5 0.33 0 30.0 138.20 56.0 5.0 3.15 14.38 14.42 1.85 55 7.52 2014 99.6 0.58 4/13 120 24.8 2.5 0.33 0 30.0 5.0 4/14 120 24.8 2.5 0.33 0 30.0 5.0 4-42 4/15 120 24.8 2.5 0.33 0 30.0 36.60 15.0 5.0 2.98 16.04 16.17 1.76 55 9.90 2345 99.7 0.65 4/16 120 24.8 2.5 0.33 0 30.0 74.80 44.8 5.0 3.25 12.72 12.96 2.29 55 9.85 38555 99.6 0.51 4/17 120 24.8 2.5 0.33 0 30.0 80.50 44.0 5.0 3.01 12.72 12.89 1.88 111 10.00 34793 99.1 0.51 4/18 120 24.8 2.5 0.33 0 30.0 86.30 44.0 5.0 3.04 12.17 12.43 1.98 55 8.66 26788 99.5 0.49 4/19 120 24.8 2.5 0.33 0 30.0 65.30 24.0 5.0 2.24 11.62 11.93 1.97 111 8.32 5188 99.0 0.46 4/20 120 24.8 2.5 0.33 0 30.0 20.0 5.0 4/21 120 24.8 2.5 0.33 0 30.0 21.0 5.0 4/22 120 24.8 2.5 0.33 0 30.0 54.60 5.0 3.39 18.81 18.89 2.32 1992 10.72 7389 89.4 0.68 4/23 120 24.8 2.5 0.33 0 30.0 63.70 51.2 5.0 3.43 13.28 13.95 3.38 1604 2.44 49495 87.9 0.47 4/24 120 24.8 2.5 0.33 0 30.0 84.4 5.0 4/25 130 22.9 2.5 0.33 0 32.5 74.20 48.0 5.0 2.62 11.62 11.80 2.40 111 9.30 10761 99.0 0.50 4/26 130 22.9 2.5 0.33 0 32.5 73.40 48.0 5.0 3.16 10.51 10.91 2.47 55 8.69 2111 99.5 0.46 4/27 140 21.2 2.5 0.33 0 35.0 5.0 4/28 140 21.2 2.5 0.33 0 35.0 5.0 4/29 140 21.2 2.5 0.33 0 35.0 50.00 5.0 3.30 9.45 9.55 2.43 333 6.92 6647 96.5 0.43 4/30 140 21.2 2.5 0.33 0 35.0 39.40 5.0 3.13 8.89 9.41 2.01 333 6.15 665 96.3 0.40 Appendix 4-2 Daily Results in Oxidation Circuit

Tank A Tank B Tank C Feed Ox. Time Nutrient Air Date pH Fe2+ T-FeBacteria Sludge Temp. pH Fe2+ T-Fe Bacteria Sludge Temp. pH Fe2+ T-FeBacteria Sludge Temp. m3/day h mg/L m3/m2/min mg/L g/L g/L v/v% ℃ mg/L g/L g/L v/v% ℃ mg/L g/L g/L v/v% ℃ 9/1 9/2 9/3 9/4 9/5 9/6 100 29.7 5.0 0.33 2.36 80 10.40 21.60 9.5 2.34 54 6.00 23.60 10.5 2.36 48 6.10 22.00 10.5 9/7 100 29.7 5.0 0.33 9/8 100 29.7 5.0 0.33 2.51 3500 6.40 24.35 9.5 16.5 2.43 290 3.10 19.53 10.0 2.39 110 2.30 21.34 9.5 9/9 100 29.7 5.0 0.33 2.67 6200 10.30 23.08 9.0 20.8 2.55 2100 5.90 22.82 10.0 20.8 2.48 74 4.40 21.74 11.0 20.8 9/10 100 29.7 5.0 0.33 3.08 12100 13.02 23.78 10.0 19.3 2.82 9400 14.80 23.84 8.8 19.5 2.64 4900 13.80 23.74 9.0 19.5 9/11 60 43.7 8.3 0.33 2.73 9510 13.40 25.00 7.0 19.4 2.67 8764 12.60 23.50 8.0 19.7 2.57 5706 11.50 23.20 7.5 20.0

4-43 9/12 50 49.5 10.0 0.33 2.98 8391 17.45 20.32 8.0 19.4 2.89 7459 12.50 22.20 8.0 19.4 2.77 5762 10.95 23.08 8.6 19.7 9/13 50 49.5 10.0 0.33 2.75 7692 11.00 20.86 8.6 18.7 2.64 6526 10.75 22.34 8.0 19.0 2.50 5035 10.60 23.52 9.0 19.6 9/14 50 59.4 10.0 0.33 2.76 7132 10.90 21.96 8.0 18.5 2.54 4196 10.50 23.30 9.0 18.9 2.44 1622 9.26 26.50 11.0 19.3 9/15 50 59.4 10.0 0.33 2.66 9230 13.00 8.0 18.5 2.41 2797 9.30 10.0 18.7 2.33 112 7.99 11.4 18.6 9/16 9/17 50 59.4 10.0 0.33 2.45 1130 15.25 51.84 56.0 18.7 2.38 280 11.90 46.22 19.0 18.7 2.38 56 9.70 38.32 17.0 18.6 9/18 50 59.4 10.0 0.33 2.37 2126 13.93 45.40 37.0 20.8 2.29 112 12.84 48.84 83.0 20.5 2.28 84 12.09 44.06 31.0 20.1 9/19 50 59.4 10.0 0.33 2.39 2909 28.41 36.90 27.0 21.1 2.31 168 19.73 42.80 36.0 20.8 2.28 84 18.97 41.26 55.0 20.0 9/20 60 49.5 5.0 0.33 2.58 3356 22.51 30.44 25.0 21.6 2.48 168 20.77 34.50 27.0 21.6 2.45 84 20.10 39.14 33.0 21.1 9/21 0 9/22 60 51.2 5.0 0.33 2.36 839 40.90 34.90 - 21.1 2.34 56 21.60 38.68 27.0 20.7 2.32 28 20.30 38.10 31.0 20.3 9/23 60 51.2 5.0 0.33 2.37 24.56 8.0 22.6 2.25 36.16 15.2 22.7 2.20 38.18 28.2 22.3 9/24 60 51.2 5.0 0.33 2.44 1622 13.90 21.70 - 19.9 2.37 28 14.25 26.70 10.5 19.7 2.33 28 14.85 31.78 17.0 19.5 9/25 70 45.0 5.0 0.33 2.35 1343 13.50 22.70 9.0 21.5 2.25 28 13.40 29.00 10.0 21.0 2.25 N.D. 13.00 31.10 12.0 20.8 9/26 70 42.5 5.0 0.33 2.18 1007 11.70 28.10 9.8 19.4 2.14 28 10.70 28.30 10.0 19.6 2.14 28 9.20 26.20 10.2 19.4 9/27 70 42.5 5.0 0.33 2.32 336 16.70 35.00 12.4 19.5 2.27 28 11.35 31.60 11.4 19.3 2.21 28 11.20 28.80 11.0 19.8 9/28 80 37.2 5.0 0.33 2.39 1007 11.80 32.14 9.0 19.8 2.31 28 11.30 34.16 10.0 19.6 2.26 28 12.00 33.06 11.0 19.4 9/29 80 37.2 5.0 0.33 2.47 2349 12.85 32.70 8.0 19.4 2.34 28 11.50 33.30 8.0 19.5 2.32 28 11.24 33.30 9.0 19.3 9/30 80 37.2 5.0 0.33 9.8 10.0 10.2 Appendix 4-2 Daily Results in Oxidation Circuit

Tank A Tank B Tank C Feed Ox. Time Nutrient Air Date pH Fe2+ T-FeBacteria Sludge Temp. pH Fe2+ T-Fe Bacteria Sludge Temp. pH Fe2+ T-FeBacteria Sludge Temp. m3/day h mg/L m3/m2/min mg/L g/L g/L v/v% ℃ mg/L g/L g/L v/v% ℃ mg/L g/L g/L v/v% ℃ 10/1 0 10/2 0 10/3 70 42.5 5.0 0.33 10/4 70 42.5 5.0 0.33 2.25 220 13.00 40.20 13.0 19.1 2.21 28 14.70 46.20 15.0 19.5 2.19 28 13.80 43.20 15.0 19.6 10/5 80 37.2 5.0 0.33 2.43 3240 16.25 43.60 40.0 21.4 2.30 28 13.30 43.90 35.0 20.8 2.24 28 12.05 43.80 13.0 20.4 10/6 80 37.2 5.0 0.33 2.52 3970 11.13 49.50 22.5 2.37 220 10.27 47.60 22.4 2.30 28 9.53 47.60 21.6 10/7 80 37.2 5.0 0.33 10/8 80 37.2 5.0 0.33 2.54 2850 19.40 21.40 21.9 2.36 110 12.71 26.20 5.0 21.9 2.30 28 12.33 8.0 22.0 10/9 80 37.2 5.0 0.33 2.53 8890 19.30 24.6 2.31 340 14.50 7.0 24.8 2.27 28 12.50 17.8 24.0 10/10 80 37.2 5.0 0.33 2.28 1120 23.10 60.00 24.1 2.25 28 14.60 42.30 84.0 23.8 2.21 28 12.60 8.10 53.0 23.1 10/11 80 37.2 5.0 0.33 2.41 4590 17.20 36.00 24.4 2.26 110 14.80 42.00 64.0 24.5 2.22 28 14.10 49.40 24.0 10/12 80 37.2 5.0 0.33 2.28 1620 15.10 38.30 21.8 2.19 28 14.70 39.30 98.0 22.3 2.18 28 14.70 45.00 21.7 10/13 80 37.2 5.0 0.33 10/14 80 37.2 5.0 0.33

4-44 10/15 80 37.2 5.0 0.33 2.61 10180 19.80 23.00 21.4 2.36 3240 18.60 25.00 23.0 2.23 170 16.70 62.00 14.0 23.1 10/16 80 37.2 5.0 0.33 2.51 5150 20.40 39.00 20.7 2.33 220 18.20 68.00 21.8 2.27 28 18.50 21.4 10/17 80 37.2 5.0 0.33 2.47 2740 26.00 31.00 20.0 2.36 60 16.30 31.10 3.0 20.3 2.34 28 15.30 43.00 33.0 19.9 10/18 80 37.2 5.0 0.33 2.55 3690 12.50 30.00 19.8 2.37 60 11.40 23.00 4.0 21.0 2.32 28 11.80 16.70 20.7 10/19 80 37.2 5.0 0.33 2.71 14360 19.90 21.40 21.4 2.35 1170 15.90 27.70 5.0 21.2 2.29 28 11.80 24.70 6.0 20.7 10/20 80 37.2 5.0 0.33 10/21 80 37.2 5.0 0.33 10/22 80 37.2 5.0 0.33 2.59 15180 23.00 33.00 22.8 2.33 7070 22.09 97.80 99.0 24.3 2.21 3400 18.60 72.10 23.9 10/23 90 33.0 5.0 0.33 2.37 7800 22.60 23.1 2.20 50 19.05 44.00 49.0 23.6 2.14 28 21.30 30.00 24.2 10/24 90 33.0 5.0 0.33 2.60 8780 18.06 15.80 21.8 2.41 1440 17.50 29.00 45.5 23.2 2.33 110 18.50 35.20 23.3 10/25 90 33.0 5.0 0.33 2.56 9390 17.70 22.30 22.2 2.33 1380 16.60 21.60 23.1 2.25 50 15.70 28.40 50.0 23.0 10/26 90 33.0 5.0 0.33 2.59 12040 20.68 17.00 20.3 2.43 3420 19.80 22.00 21.0 2.33 220 17.80 25.00 33.0 21.0 10/27 90 33.0 5.0 0.33 10/28 90 33.0 5.0 0.33 10/29 90 33.0 5.0 0.33 2.52 13200 25.08 21.50 25.4 2.28 5470 22.39 27.60 26.0 2.19 280 20.20 39.80 25.3 10/30 90 33.0 5.0 0.33 2.46 9610 19.66 16.80 22.3 2.21 2100 18.60 28.30 24.2 2.11 110 17.70 39.50 24.0 10/31 90 33.0 5.0 0.33 2.32 3040 15.85 23.7 2.21 110 15.50 24.0 2.15 28 16.30 23.9 Appendix 4-2 Daily Results in Oxidation Circuit

Tank A Tank B Tank C Feed Ox. Time Nutrient Air Date pH Fe2+ T-FeBacteria Sludge Temp. pH Fe2+ T-Fe Bacteria Sludge Temp. pH Fe2+ T-FeBacteria Sludge Temp. m3/day h mg/L m3/m2/min mg/L g/L g/L v/v% ℃ mg/L g/L g/L v/v% ℃ mg/L g/L g/L v/v% ℃ 11/1 11/2 70 42.45943 5.0 0.33 11/3 70 42.45943 5.0 0.33 11/4 70 42.45943 5.0 0.33 11/5 70 42.45943 5.0 0.33 11/6 80 37.152 5.0 0.33 2.34 4190 17.77 22.50 22.2 2.23 220 14.65 29.40 21.9 2.17 50 13.48 27.90 21.1 11/7 80 37.152 5.0 0.33 2.50 5630 16.38 20.90 21.3 2.31 280 14.77 26.60 21.7 2.16 28 14.42 31.80 21.0 11/8 80 37.152 5.0 0.33 2.50 3920 15.40 20.90 22.6 2.35 170 14.10 25.60 23.2 2.30 28 13.80 28.40 22.8 11/9 90 33.024 5.0 0.33 2.48 4640 14.70 17.70 20.9 2.30 220 14.37 20.20 21.7 2.23 28 13.57 24.20 21.5 11/10 90 33.024 5.0 0.33 2.53 4140 12.51 26.00 19.4 2.34 280 12.92 23.40 20.4 2.28 28 12.62 24.20 20.3 11/11 90 33.024 5.0 0.33 11/12 90 33.024 5.0 0.33 2.69 14900 23.72 16.50 24.0 2.34 4310 20.30 4.30 24.9 2.24 170 15.38 13.70 24.7 11/13 100 29.7216 5.0 0.33 2.46 8230 25.82 25.60 22.6 2.20 1550 25.60 8.50 23.3 2.16 28 23.88 18.30 22.9 11/14 100 29.7216 5.0 0.33 2.55 6630 22.81 24.50 22.9 2.37 660 23.55 30.30 25.1 2.31 28 23.30 35.70 24.8 4-45 11/15 100 29.7216 5.0 0.33 2.51 6070 24.05 6.56 22.4 2.34 440 20.80 9.77 23.8 2.27 28 18.85 8.76 24.3 11/16 100 29.7216 5.0 0.33 2.54 5670 17.50 14.25 22.4 2.37 330 12.05 21.30 23.2 2.30 28 11.65 24.30 22.8 11/17 100 29.7216 5.0 0.33 11/18 100 29.7216 5.0 0.33 11/19 100 29.7216 5.0 0.33 2.53 8340 18.35 18.10 24.3 2.31 880 17.30 7.70 25.7 2.24 28 15.10 22.50 25.2 11/20 100 29.7216 5.0 0.33 2.57 7010 19.95 25.80 22.3 2.38 500 18.80 12.00 23.5 2.38 28 16.82 20.10 23.5 11/21 100 29.7216 5.0 0.33 2.51 3420 16.68 21.10 20.9 2.40 220 17.99 29.50 22.5 2.36 28 16.84 30.40 22.2 11/22 100 29.7216 5.0 0.33 2.44 3420 14.83 22.20 21.5 2.36 28 14.18 26.00 22.3 2.31 28 15.66 31.30 22.3 11/23 110 27.01964 5.0 0.33 2.43 2650 13.17 22.70 21.9 2.31 28 13.12 24.90 23.1 2.29 28 13.71 27.50 22.6 11/24 110 27.01964 5.0 0.33 11/25 110 27.01964 5.0 0.33 2.38 21.30 46.0 24.4 2.22 22.90 35.0 24.6 2.20 22.30 32.0 24.4 11/26 110 27.01964 5.0 0.33 1.99 3700 11.27 22.62 23.0 23.7 1.87 220 10.39 27.52 32.0 23.6 1.83 28 9.36 29.68 35.0 23.4 11/27 110 27.01964 5.0 0.33 1.99 1100 25.72 25.0 19.1 2.15 110 30.72 30.0 18.8 1.98 50 30.76 29.0 19.1 11/28 110 27.01964 5.0 0.33 2.17 N.D. 46.46 39.0 22.1 2.16 N.D. 33.04 31.0 22.8 2.14 N.D. 31.44 28.0 22.8 11/29 90 33.024 5.0 0.33 2.26 170 10.25 34.28 30.2 23.0 2.24 N.D. 9.50 34.16 30.0 23.2 2.26 N.D. 10.00 32.20 29.4 23.0 11/30 110 27.01964 5.0 0.33 2.26 880 8.37 31.96 23.5 23.0 2.15 28 8.42 31.88 26.0 23.3 2.07 N.D. 9.20 32.52 28.0 22.7 Appendix 4-2 Daily Results in Oxidation Circuit

Tank A Tank B Tank C Feed Ox. Time Nutrient Air Date pH Fe2+ T-FeBacteria Sludge Temp. pH Fe2+ T-Fe Bacteria Sludge Temp. pH Fe2+ T-FeBacteria Sludge Temp. m3/day h mg/L m3/m2/min mg/L g/L g/L v/v% ℃ mg/L g/L g/L v/v% ℃ mg/L g/L g/L v/v% ℃ 12/1 110 27.01964 5.0 0.33 12/2 110 27.01964 5.0 0.33 12/3 110 27.01964 5.0 0.33 2.28 280 10.05 45.88 14.0 20.9 2.26 N.D. 9.65 42.36 13.0 20.8 2.23 N.D. 9.21 38.76 15.0 20.9 12/4 110 27.01964 5.0 0.33 2.39 940 9.26 38.64 15.0 20.8 2.32 28 10.30 45.40 20.0 20.7 2.29 N.D. 9.10 39.12 21.0 20.9 12/5 110 27.01964 5.0 0.33 2.36 770 7.86 34.04 11.0 21.9 2.28 28 8.11 39.40 14.0 22.5 2.23 N.D. 8.00 40.44 16.0 22.6 12/6 110 27.01964 5.0 0.33 2.35 880 11.02 35.84 9.0 23.0 2.25 28 7.46 40.32 10.0 23.6 2.21 N.D. 7.22 38.20 10.0 23.7 12/7 100 29.7216 5.0 0.33 2.33 3200 10.83 38.48 9.0 24.7 2.19 N.D. 8.84 39.08 11.0 24.7 2.15 N.D. 7.30 38.64 10.0 29.2 12/8 100 29.7216 5.0 0.33 27.0 12.0 11.0 12/9 100 29.7216 5.0 0.33 20.0 24.0 22.0 12/10 100 29.7216 5.0 0.33 2.22 48.88 25.0 25.1 2.16 49.80 27.0 25.6 2.14 48.76 26.0 25.7 12/11 100 29.7216 5.0 0.33 2.38 4580 12.38 52.16 16.0 22.7 2.23 N.D. 10.59 49.60 18.0 22.9 2.16 28 9.90 50.20 23.0 23.1 12/12 100 29.7216 5.0 0.33 2.44 5470 13.30 56.48 16.0 24.2 2.29 N.D. 12.02 55.68 24.0 2.22 28 11.43 57.36 15.0 23.9 12/13 100 29.7216 5.0 0.33 2.44 4970 12.02 39.68 9.0 24.3 2.30 N.D. 11.15 45.00 10.0 24.2 2.22 28 11.20 52.16 12.0 23.9 12/14 100 29.7216 5.0 0.33 2.49 4750 11.48 29.90 2.0 21.3 2.29 N.D. 10.24 31.60 2.0 21.8 2.22 28 10.00 37.60 4.0 21.8

4-46 12/15 100 29.7216 5.0 0.33 2.53 2.28 10.0 2.24 11.0 12/16 100 29.7216 5.0 0.33 12/17 100 29.7216 5.0 0.33 2.15 610 62.56 80.0 25.4 2.09 28 58.56 60.0 25.7 2.05 28 49.24 45.0 25.8 12/18 100 29.7216 5.0 0.33 2.20 440 10.65 41.76 35.0 27.0 2.14 28 10.45 50.96 45.0 26.9 2.12 28 10.60 56.64 51.0 27.2 12/19 100 29.7216 5.0 0.33 2.21 940 8.42 40.28 28.0 24.1 2.09 28 8.47 43.68 35.0 24.4 2.04 28 9.50 48.04 42.0 24.3 12/20 100 29.7216 5.0 0.33 2.19 820 7.38 34.04 22.0 24.9 2.08 28 6.83 41.08 25.0 25.1 2.05 28 7.23 41.20 30.0 24.4 12/21 100 29.7216 5.0 0.33 2.50 10160 15.45 32.76 12.5 25.2 2.35 1 10.15 36.36 25.0 25.3 2.31 28 8.17 35.96 26.4 24.6 12/22 100 29.7216 5.0 0.33 12/23 110 27.01964 5.0 0.33 12/24 110 27.01964 5.0 0.33 2.20 3640 10.20 42.64 25.0 25.0 2.07 N.D. 9.16 46.04 33.0 25.9 2.02 28 8.82 49.80 31.0 25.9 12/25 110 27.01964 5.0 0.33 58.64 22.0 45.36 28.0 43.23 29.0 12/26 5.0 0.33 12/27 5.0 0.33 2.12 280 9.60 58.64 27.0 25.0 2.12 N.D. 7.31 45.36 24.0 24.3 2.09 N.D. 6.92 43.28 54.0 24.2 12/28 5.0 0.33 2.00 79.64 32.0 22.7 1.99 65.60 26.0 22.9 1.98 54.88 22.0 23.1 12/29 80 37.152 5.0 0.33 12/30 100 29.7216 5.0 0.33 12/31 100 29.7216 5.0 0.33 2.35 4200 9.37 49.80 20.0 24.1 2.33 N.D. 8.39 50.16 25.0 24.3 2.32 28 8.06 55.72 27.0 24.2 Appendix 4-2 Daily Results in Oxidation Circuit

4-47 1/15 100 29.7216 2.5 0.33 2.15 9490 15.21 80.52 14.0 25.9 1.98 1 12.25 82.20 20.0 26.8 1.91 28 10.89 92.88 18.0 25.4 1/16 100 29.7216 2.5 0.33 2.15 5240 12.69 81.52 15.0 24.4 2.03 N.D. 11.14 85.60 26.0 24.5 1.98 28 12.55 85.08 25.0 24.8 1/17 100 37.152 2.5 0.33 2.04 1950 17.70 84.88 21.0 25.4 1.95 28 10.14 88.96 26.0 25.6 1.93 28 12.12 85.84 25.0 24.9 1/18 100 29.7216 2.5 0.33 2.00 670 9.70 104.04 22.0 24.3 1.97 28 9.44 113.64 21.0 24.6 1.94 28 9.86 88.60 23.0 25.0 1/19 100 29.7216 2.5 0.33 1/20 100 29.7216 2.5 0.33 1/21 100 29.7216 2.5 0.33 2.15 6810 12.40 66.76 12.0 24.2 1.99 N.D. 11.34 69.32 15.0 25.1 1.94 N.D. 10.09 71.76 20.0 24.6 1/22 100 29.7216 2.5 0.33 2.11 5470 11.87 62.00 11.0 25.1 1.97 N.D. 11.08 60.76 13.0 25.4 1.92 28 10.79 63.44 14.0 25.3 1/23 100 29.7216 2.5 0.33 2.16 5250 10.00 65.00 7.0 23.9 1.96 N.D. 9.37 68.00 13.0 25.2 1.91 28 9.27 64.00 14.0 25.2 1/24 100 29.7216 2.5 0.33 2.04 4240 9.56 66.00 11.0 24.3 1.91 N.D. 8.40 71.12 13.0 25.0 1.87 28 8.79 68.40 14.0 24.9 1/25 100 29.7216 2.5 0.33 2.14 3620 9.22 62.24 20.0 23.3 1.93 N.D. 8.74 82.12 28.0 23.1 1.92 28 8.45 75.52 30.0 23.3 1/26 100 29.7216 2.5 0.33 1/27 100 29.7216 2.5 0.33 1/28 90 33.024 2.5 0.33 2.25 6080 11.92 104.68 4.0 25.0 2.01 1 11.28 75.16 9.0 25.8 1.94 28 11.28 76.76 9.0 25.7 1/29 90 33.024 2.5 0.33 2.29 7140 10.10 49.84 10.0 23.2 1.95 N.D. 9.56 67.00 16.0 24.4 1.89 28 9.37 68.00 22.0 24.3 1/30 1.89 N.D. 13.16 70.00 16.0 24.6 1.87 N.D. 9.17 70.00 14.0 24.9 1.86 N.D. 8.83 68.00 19.0 24.9 1/31 50 59.4 2.5 0.33 1.75 N.D. 10.19 78.32 22.4 22.7 1.75 N.D. 8.98 69.68 19.4 23.3 1.74 N.D. 8.30 72.12 19.4 23.3 Appendix 4-2 Daily Results in Oxidation Circuit

Tank A Tank B Tank C Feed Ox. Time Nutrient Air Date pH Fe2+ T-FeBacteria Sludge Temp. pH Fe2+ T-Fe Bacteria Sludge Temp. pH Fe2+ T-FeBacteria Sludge Temp. m3/day h mg/L m3/m2/min mg/L g/L g/L v/v% ℃ mg/L g/L g/L v/v% ℃ mg/L g/L g/L v/v% ℃ 2/1 100 29.7 2.5 0.33 1.90 6810 12.60 51.76 11.0 23.3 1.78 1 9.23 61.80 16.0 23.7 1.75 28 8.75 71.48 18.0 23.6 2/2 100 29.7 2.5 0.33 2/3 100 29.7 2.5 0.33 2/4 90 33.0 2.5 0.33 1.73 28 10.63 99.80 31.4 23.3 1.69 28 9.76 78.80 29.4 24.0 1.67 28 10.00 71.24 25.0 24.2 2/5 100 29.7 2.5 0.33 1.95 2510 9.24 68.00 19.0 23.0 1.85 N.D. 9.53 77.56 24.0 23.4 1.80 28 10.00 80.56 26.0 23.5 2/6 100 29.7 2.5 0.33 1.86 1620 7.54 73.56 20.0 22.9 1.76 28 8.22 77.20 27.0 23.1 1.61 N.D. 8.61 78.56 26.0 23.0 2/7 100 29.7 2.5 0.33 1.91 8010 13.84 77.80 19.0 24.2 1.79 1 9.21 82.32 28.0 24.3 1.69 28 8.08 83.60 27.0 24.0 2/8 100 29.7 2.5 0.33 2.26 17250 23.11 69.32 13.0 23.5 1.94 3 14.93 81.68 22.0 23.9 1.87 N.D. 11.67 80.96 27.0 23.4 2/9 100 29.7 2.5 0.33 15.0 25.0 27.0 2/10 100 29.7 2.5 0.33 2/11 100 29.7 2.5 0.33 1.65 170 13.79 118.70 37.0 24.8 1.62 28 17.25 95.12 30.0 25.0 1.60 28 14.88 85.50 28.0 25.3 2/12 100 29.7 2.5 0.33 1.97 8420 15.53 74.00 21.0 24.1 1.76 1 14.42 94.40 20.0 24.8 1.70 28 14.56 104.20 15.0 24.3 2/13 100 29.7 2.5 0.33 2.41 5470 11.88 79.00 13.0 23.4 2.24 N.D. 14.27 79.00 10.0 24.3 2.18 28 13.19 87.00 17.0 24.3 4-48 2/14 100 29.7 2.5 0.33 2.23 3290 11.64 88.00 18.0 23.5 2.12 N.D. 10.79 90.00 17.0 24.1 2.07 28 11.31 80.00 15.0 24.0 2/15 100 29.7 2.5 0.33 2.43 9820 19.62 13.0 23.2 2.16 1 12.39 15.0 23.7 2.11 28 11.74 16.0 23.0 2/16 100 29.7 2.5 0.33 2/17 100 29.7 2.5 0.33 2/18 80 37.2 2.5 0.33 2.61 15460 25.95 83.00 7.0 22.6 2.22 2 17.70 96.00 7.0 23.9 2.15 28 13.65 94.00 9.0 23.7 2/19 50 59.4 2.5 0.33 2.32 10160 25.85 6.0 22.4 2.11 N.D. 12.20 22.3 2.12 N.D. 11.60 98.0 22.4 2/20 60 49.5 2.5 0.33 2.23 4970 20.84 44.00 23.9 2.10 N.D. 15.79 24.0 2.07 28 13.32 23.5 2/21 70 42.5 2.5 0.33 2.23 2790 14.41 37.00 67.0 22.5 2.08 N.D. 14.00 49.00 97.0 22.9 2.06 28 14.16 48.00 99.0 22.9 2/22 90 33.0 2.5 0.33 2.23 2070 16.32 45.52 80.0 23.4 2.08 28 10.70 51.48 57.0 23.5 2.03 28 12.69 55.00 97.0 23.1 2/23 90 33.0 2.5 0.33 2/24 90 33.0 2.5 0.33 2/25 90 33.0 2.5 0.33 2.57 9990 14.63 21.96 25.0 25.4 2.23 1 10.79 26.76 90.0 25.8 2.11 28 9.41 29.36 36.0 25.1 2/26 90 33.0 2.5 0.33 2.60 8650 15.17 23.92 60.0 24.0 2.36 1 12.63 32.04 59.0 23.9 2.29 28 10.75 37.64 39.0 23.8 2/27 0 2/28 70 42.5 2.5 0.33 2.17 28 18.46 34.40 32.0 22.4 2.14 N.D. 10.37 36.50 31.0 23.4 2.13 28 10.89 30.30 30.0 23.2 Appendix 4-2 Daily Results in Oxidation Circuit

4-49 3/15 100 29.7 2.5 0.33 2.31 8300 14.04 22.00 94.0 23.2 2.10 1 11.43 27.00 99.0 23.5 2.02 28 11.58 33.00 98.0 23.3 3/16 100 29.7 2.5 0.33 87.0 53.0 98.0 3/17 100 29.7 2.5 0.33 96.0 42.0 92.0 3/18 100 29.7 2.5 0.33 1.90 2430 11.77 24.00 40.0 26.2 1.79 28 11.72 27.00 95.0 27.3 1.79 28 18.67 58.00 90.0 26.6 3/19 100 29.7 2.5 0.33 2.25 4200 15.35 16.00 39.0 24.0 2.10 N.D. 10.69 20.00 33.0 24.6 2.00 28 11.19 30.00 79.0 24.7 3/20 110 27.0 2.5 0.33 2.28 4480 9.16 14.00 15.0 23.8 2.13 N.D. 9.35 18.00 18.0 24.1 2.03 28 9.70 21.00 26.0 24.1 3/21 110 27.0 2.5 0.33 2.25 2930 7.75 16.00 19.0 22.9 2.06 N.D. 7.40 17.00 16.0 23.5 2.05 28 9.61 15.00 19.0 23.3 3/22 110 27.0 2.5 0.33 1.93 440 6.75 22.00 16.0 22.9 1.78 28 6.75 20.00 18.0 23.6 1.76 28 7.29 18.00 17.0 23.6 3/23 110 27.0 2.5 0.33 3/24 110 27.0 2.5 0.33 3/25 70 42.5 2.5 0.33 2.51 60 8.03 19.00 19.0 22.4 2.44 28 6.90 25.00 19.0 22.5 2.41 28 6.55 30.00 17.0 22.6 3/26 90 33.0 2.5 0.33 2.00 280 12.00 28.00 18.0 25.7 1.89 28 10.93 29.00 18.0 21.8 1.87 N.D. 11.85 33.00 15.0 21.5 3/27 100 29.7 2.5 0.33 2.03 1000 8.23 28.00 30.0 22.5 1.92 28 7.04 29.00 34.0 22.6 1.87 28 7.14 31.00 34.0 22.6 3/28 110 27.0 2.5 0.33 2.00 60 8.87 20.0 22.5 1.93 N.D. 8.33 20.0 22.5 1.88 N.D. 8.33 18.5 22.8 3/29 110 27.0 2.5 0.33 3/30 110 27.0 2.5 0.33 3/31 90 33.0 2.5 0.33 Appendix 4-2 Daily Results in Oxidation Circuit

Tank A Tank B Tank C Feed Ox. Time Nutrient Air Date pH Fe2+ T-FeBacteria Sludge Temp. pH Fe2+ T-Fe Bacteria Sludge Temp. pH Fe2+ T-FeBacteria Sludge Temp. m3/day h mg/L m3/m2/min mg/L g/L g/L v/v% ℃ mg/L g/L g/L v/v% ℃ mg/L g/L g/L v/v% ℃ 4/1 100 29.7 2.5 0.33 1.91 940 4.57 35.64 21.6 1.89 55 3.81 32.96 21.6 1.96 28 4.11 31.76 21.3 4/2 100 29.7 2.5 0.33 2.21 940 5.98 47.36 18.4 20.6 2.12 55 5.28 51.48 21.0 20.7 2.08 28 5.13 48.40 21.0 20.9 4/3 100 29.7 2.5 0.33 2.30 8851 12.44 42.72 14.0 20.8 2.08 996 7.46 44.68 17.6 20.6 2.03 28 5.47 45.96 19.0 20.4 4/4 100 29.7 2.5 0.33 2.68 16596 18.73 14.0 24.6 2.17 5034 12.99 13.6 24.4 2.08 498 9.46 18.4 24.2 4/5 80 37.2 2.5 0.33 4/6 80 37.2 2.5 0.33 4/7 90 33.0 2.5 0.33 4/8 90 33.0 2.5 0.33 1.75 277 10.49 75.56 30.0 22.2 1.73 55 11.08 76.48 30.0 22.1 1.69 553 11.96 75.36 28.0 22.7 4/9 90 33.0 2.5 0.33 2.11 1881 10.83 55.68 21.0 20.5 2.01 55 10.39 65.88 26.0 20.7 1.88 55 10.97 71.96 27.0 20.6 4/10 110 27.0 2.5 0.33 2.19 2987 9.26 46.20 22.1 2.08 221 9.01 54.16 22.5 2.03 55 9.46 63.00 22.6 4/11 120 24.8 2.5 0.33 2.20 3817 7.82 26.96 12.0 20.3 1.97 553 8.07 33.68 16.0 20.6 1.95 55 8.17 71.48 17.0 20.7 4/12 120 24.8 2.5 0.33 2.17 4592 9.81 52.36 10.0 20.4 2.03 553 8.06 63.72 13.0 20.6 1.86 55 7.67 60.08 14.0 20.2 4/13 120 24.8 2.5 0.33 10.0 10.0 10.0 4/14 120 24.8 2.5 0.33 4-50 4/15 120 24.8 2.5 0.33 1.83 609 11.50 50.24 15.0 22.9 1.72 55 10.68 53.48 25.0 22.9 1.87 55 10.97 54.44 15.0 22.3 4/16 120 24.8 2.5 0.33 2.44 2711 11.21 42.72 27.0 20.8 2.34 277 12.38 47.40 31.0 21.0 2.30 111 10.68 52.12 36.0 20.9 4/17 120 24.8 2.5 0.33 2.13 4536 10.29 32.04 20.0 20.3 1.97 664 9.85 40.68 26.0 20.7 1.90 221 9.31 44.40 27.0 20.9 4/18 120 24.8 2.5 0.33 2.28 4979 10.15 32.48 4.0 20.1 2.08 940 8.86 32.36 10.0 20.6 1.98 166 14.21 38.76 15.0 20.9 4/19 120 24.8 2.5 0.33 2.26 6085 10.05 15.12 1.0 20.2 2.11 2213 9.85 17.60 2.0 21.0 1.98 277 9.21 28.28 6.0 20.9 4/20 120 24.8 2.5 0.33 12.0 16.0 16.0 4/21 120 24.8 2.5 0.33 20.0 22.0 20.0 4/22 120 24.8 2.5 0.33 2.92 14660 16.20 16.76 22.6 2.58 9017 14.09 15.32 21.4 2.40 3043 12.02 15.16 21.8 4/23 120 24.8 2.5 0.33 2.74 8077 13.02 20.12 16.0 19.7 2.59 5809 15.22 21.84 1.0 19.8 2.48 1660 12.00 26.72 25.0 19.8 4/24 120 24.8 2.5 0.33 21.0 26.0 31.0 4/25 130 22.9 2.5 0.33 2.44 3706 9.80 18.60 14.0 19.3 2.40 498 8.80 22.56 17.0 19.9 2.40 111 9.25 24.00 19.0 19.9 4/26 130 22.9 2.5 0.33 2.64 4149 8.59 19.60 10.0 18.9 2.49 609 8.33 16.68 20.0 19.3 2.43 111 8.38 25.80 17.0 19.6 4/27 140 21.2 2.5 0.33 4/28 140 21.2 2.5 0.33 4/29 140 21.2 2.5 0.33 2.84 6335 8.86 9.72 23.0 2.56 3112 7.86 12.96 22.7 2.45 722 6.82 16.80 22.8 4/30 140 21.2 2.5 0.33 2.36 4612 7.95 13.44 19.2 1.99 1556 6.73 13.96 19.8 2.06 222 6.10 16.36 19.7 Appendix 4-3 Daily Results in Neutralization Circuit

Neutralization with Calcium Carbonate Neutralization with Slaked Lime Filter Press Total Cake Addition of Quality of Neutralized Solution Volume of Addition of Quality of Neutralized Solution Volume of Volume Moisture Amount of Neut. pH Date Feed Neut. Time 2+ Feed Neut. Time Times Content Product CaCO3 pH Fe T-Fe Cu SedimentSediment Ca(OH)2 pH T-Fe Mn Mg Sediment Sediment (wet) m3/day g/L h mg/L mg/L mg/L g/L t/day m3/day g/L h mg/L mg/L mg/L g/L t/day Times/day m3/day % t/day 9/1 9/2 9/3 9/4 9/5 9/6 100 3.0 0 9/7 100 3.0 0 9/8 100 3.0 2.1 3.57 40 500 133 10.68 4 1.3 9/9 100 4.5 2.1 5.16 4 500 28.84 8 1.3 4.94 800.0 15.44 1 3.1 45.00 4.6 9/10 100 4.5 2.1 5.01 2300 2300 41 48.16 8 1.3 8.20 1800.0 189.0 3573 2.64 2 6.2 44.67 9.3 9/11 60 4.5 3.4 5.28 1600 2600 3.6 97.70 12 1.3 8.41 0.2 92.0 4079 0.04 3 8.5 41.55 13.1 4-51 9/12 50 3.2 4.1 2.78 5091 10150 117 1.52 10 1.3 4.46 1 3.1 45.04 4.6 9/13 50 3.2 4.1 3.30 5146 5800 116 26.02 16 1.3 8.48 0.2 1.6 2734 48.36 52.86 9/14 50 3.2 4.1 3.12 3186 3793 116 23.54 8 1.3 7.93 0.8 1.3 1570 47.06 1 3.4 45.00 5.1 9/15 50 3.2 4.1 3.19 28 343 28.31 10 1.3 8.50 36.86 1 3.2 44.18 4.8 9/16 0 1 3.2 45.00 4.8 9/17 50 3.2 4.1 3.51 N.D. 56 38.26 0 ---- - 13.245.00 4.8 9/18 50 3.2 4.1 3.79 N.D. 135 67 37.80 0 ---- - 26.145.31 9.1 9/19 50 3.2 4.1 2.65 28 9070 126 30.18 0 ---- - 12.846.70 4.1 9/20 60 3.5 3.4 3.76 N.D. 2293 92 77.40 0 ---- - 310.1 48.27 14.6 9/21 0 0 45.00 9/22 60 3.5 3.4 3.41 N.D. 389 98 44.40 8 1.3 ---- - 13.348.80 4.8 9/23 60 3.5 3.4 3.72 44.40 16 1.3 8.34 3 10.8 48.73 15.6 9/24 60 3.5 3.4 3.67 N.D. 1400 78 63.94 12 1.3 8.43 3.0 18.0 3850 24.96 2 6.8 49.38 9.8 9/25 70 3.5 2.9 3.68 N.D. 1379 78 57.00 10 1.3 8.40 0.4 6.0 810 34.00 2 5.5 50.80 7.8 9/26 70 3.5 2.9 3.22 N.D. 400 84 50.00 6 1 2.5 50.00 3.6 9/27 70 3.5 2.9 3.49 N.D. 332 104 45.20 6 2 6.2 46.80 9.1 9/28 80 3.5 2.6 3.83 N.D. 412 46.44 8 1.1 8.44 2.7 36.14 3 9.5 47.09 13.9 9/29 80 3.5 2.6 4.01 N.D. 149 48.00 4 0.9 8.43 32.24 2 6.8 53.80 9.4 9/30 80 3.5 2.6 3.80 4 0.9 8.58 3 8.6 52.30 12.0 Appendix 4-3 Daily Results in Neutralization Circuit

4-52 10/15 80 3.5 2.6 2.74 60 1050 62 50.00 6 1.0 4 9.8 48.34 14.2 10/16 80 3.5 2.6 3.52 N.D. 830 82 76.00 3 1.0 2 5.3 46.68 7.8 10/17 80 3.5 2.6 3.61 28 4190 108 102.00 6 1.0 7.65 1.4 90.0 27.00 2 5.0 46.01 7.4 10/18 80 3.5 2.6 3.32 N.D. 2100 112 83.50 5 1.0 4 8.9 42.03 13.7 10/19 80 3.5 2.6 3.68 N.D. 940 69 72.50 7 1.0 4 9.1 44.04 13.8 10/20 80 3.5 2.6 6 1.0 3 7.2 43.76 10.8 10/21 80 3.5 2.6 6 1.0 4 10.1 46.76 14.8 10/22 80 3.5 2.6 3.80 220 483 65 121.00 4 1.0 4 9.0 46.91 13.2 10/23 90 3.5 2.3 3.37 N.D. 245 73 123.00 2 1.0 7.79 5.9 187.0 27.00 4 9.3 48.21 13.5 10/24 90 3.5 2.3 3.23 N.D. 398 83 87.00 5 1.0 8.17 0.4 38.0 35.00 3 7.7 50.03 11.0 10/25 90 3.5 2.3 3.49 N.D. 265 86 93.00 0 1.0 3 7.9 46.65 11.6 10/26 90 3.5 2.3 3.41 N.D. 299 75 90.10 3 1.0 4 10.8 45.29 16.1 10/27 90 3.5 2.3 5 1.0 4 11.9 46.82 17.5 10/28 90 3.5 2.3 6 1.0 4 11.8 48.75 17.0 10/29 90 3.5 2.3 3.09 110 609 95 86.30 1 1.0 7.66 1.4 84.0 27.40 6 8.2 50.47 11.7 10/30 90 3.5 2.3 3.45 N.D. 244 89 102.00 1 1.0 9 11.5 54.24 15.9 10/31 90 3.5 2.3 3 1.0 7.62 0.4 3 5.4 53.89 7.4 Appendix 4-3 Daily Results in Neutralization Circuit

Neutralization with Calcium Carbonate Neutralization with Slaked Lime Filter Press Total Cake Addition of Quality of Neutralized Solution Volume of Addition of Quality of Neutralized Solution Volume of Volume Moisture Amount of Neut. pH Date Feed Neut. Time 2+ Feed Neut. Time Times Content Product CaCO3 pH Fe T-Fe Cu SedimentSediment Ca(OH)2 pH T-Fe Mn Mg Sediment Sediment (wet) m3/day g/L h mg/L mg/L mg/L g/L t/day m3/day g/L h mg/L mg/L mg/L g/L t/day Times/day m3/day % t/day 11/1 0 11/2 70 3.5 2.9 0 1.0 1 1.8 53.02 2.5 11/3 70 3.5 2.9 1 1.0 1 2.7 49.40 3.9 11/4 70 3.5 2.9 1 1.0 1 2.6 52.68 3.6 11/5 70 3.5 2.9 3 1.0 2 5.0 51.45 7.1 11/6 80 3.5 2.6 3.76 28 571 113 87.18 2 1.0 4 10.6 52.29 14.9 11/7 80 3.5 2.6 3.64 N.D. 347 94 97.72 4 1.0 3 8.3 50.38 11.8 11/8 80 3.5 2.6 3.45 N.D. 165 111 75.70 2 1.0 4 10.9 45.90 16.1 11/9 90 3.5 2.3 3.70 N.D. 352 72.00 4 1.0 4 10.3 46.03 15.2 11/10 90 3.5 2.3 3.53 N.D. 138 65.30 4 1.0 4 10.2 46.14 15.1 11/11 90 3.5 2.3 3 1.0 2 5.3 46.04 7.8 11/12 90 3.5 2.3 3.36 N.D. 306 66.00 5 1.0 4 9.0 47.36 13.2 11/13 100 3.5 2.1 3.85 N.D. 1348 86.00 4 1.0 6 13.2 47.29 19.3 11/14 100 3.5 2.1 3.47 N.D. 1305 93.50 6 1.0 6 12.5 46.33 18.4 4-53 11/15 100 3.5 2.1 3.48 N.D. 875 39.77 4 1.0 7 13.7 49.28 19.7 11/16 100 3.5 2.1 3.54 N.D. 995 67.26 4 1.0 7.97 0.5 28.04 4 8.8 49.40 12.6 11/17 100 3.5 2.1 5 1.0 5 11.2 47.74 16.3 11/18 100 3.5 2.1 1 1.0 5 12.7 45.00 19.0 11/19 100 3.5 2.1 3.31 535 71.12 3 1.0 8.10 0.2 35.68 4 10.6 44.10 15.9 11/20 100 3.5 2.1 3.60 284 77.98 2 1.0 3 6.6 44.75 9.9 11/21 100 3.5 2.1 3.50 266 93.68 1 1.0 7.82 0.5 35.52 5 11.0 45.01 16.4 11/22 100 3.5 2.1 3.55 N.D. 207 85.82 2 1.0 8.11 N.D. 29.14 5 12.3 44.20 18.5 11/23 110 3.5 1.9 3.42 N.D. 937 82.40 3 1.0 7 17.7 45.23 26.4 11/24 110 3.5 1.9 3 1.0 6 14.4 47.13 21.1 11/25 110 3.5 1.9 4 1.0 4 10.3 47.28 15.1 11/26 110 3.5 1.9 3.58 N.D. 515 66.68 2 1.0 7.36 0.1 8.50 6 14.3 47.50 20.9 11/27 110 3.5 1.9 4 1.0 5 9.2 48.68 13.3 11/28 110 3.5 1.9 0 1.0 11/29 90 3.5 2.3 2 1.0 2 2.8 50.72 4.0 11/30 110 3.5 1.9 4.36 N.D. 69 41.74 2 1.0 7 13.7 48.87 19.8 Appendix 4-3 Daily Results in Neutralization Circuit

4-54 12/15 100 3.5 2.1 0 5 11.8 42.33 18.0 12/16 100 3.5 2.1 0 0 12/17 100 3.5 2.1 3.91 N.D. 57.48 1 4 8.9 47.62 13.0 12/18 100 3.5 2.1 3.66 N.D. 130 84.56 2 4 9.7 47.43 14.2 12/19 100 3.5 2.1 3.68 N.D. 46 77.08 1 7 17.2 48.23 24.9 12/20 100 3.5 2.1 3.67 N.D. 45 55.00 1 N.D. 24.52 5 12.0 46.36 17.7 12/21 100 3.5 2.1 3.81 N.D. 45 58.68 5 0.2 17.68 4 9.6 47.28 14.0 12/22 100 3.5 2.1 3 5 11.7 48.56 16.9 12/23 110 3.5 1.9 1 5 11.3 48.23 16.4 12/24 110 3.5 1.9 3.45 N.D. 148 39.80 2 7.45 0.1 12.24 7 15.0 56.29 20.3 12/25 110 3.5 1.9 2 4 8.8 46.77 12.9 12/26 0 0 0.0 12/27 0 0 0.0 12/28 0 0 0.0 12/29 80 3.5 2.6 0 0 0.0 12/30 100 3.5 2.1 0 3 7.3 47.74 10.6 12/31 100 3.5 2.1 3.48 N.D. 330 0 3 8.1 50.00 11.6 Appendix 4-3 Daily Results in Neutralization Circuit

4-55 1/15 100 3.5 2.1 3.51 N.D. 1376 44.52 2 8.08 3.5 19.72 2 5.4 41.41 8.3 1/16 100 3.5 2.1 3.53 N.D. 137 37.68 3 7.98 1.1 7.80 2 5.6 48.89 8.1 1/17 100 3.5 2.1 4.26 N.D. 304 36.80 0 2 5.4 48.15 7.8 1/18 100 3.5 2.1 3.61 N.D. 88 29.24 1 0 0.0 1/19 100 3.5 2.1 1 1 2.8 44.82 4.2 1/20 100 3.5 2.1 1 3 8.3 49.66 11.9 1/21 100 3.5 2.1 4.19 N.D. 134 29.04 4 3 8.0 47.82 11.6 1/22 100 3.5 2.1 3.65 N.D. 108 34.44 4 3 8.3 47.27 12.1 1/23 100 3.5 2.1 4.28 N.D. 117 29.00 3 3 7.8 48.14 11.3 1/24 100 3.5 2.1 3.78 N.D. 87 30.24 3 3 8.3 49.78 11.9 1/25 100 3.5 2.1 3.39 N.D. 67 41.04 4 3 8.5 48.98 12.2 1/26 100 3.5 2.1 0 3 8.2 50.58 11.7 1/27 100 3.5 2.1 1 3 8.9 45.40 13.2 1/28 90 3.5 2.3 3.52 N.D. 251 22.90 5 3 8.8 46.06 13.0 1/29 90 3.5 2.3 3.50 N.D. 121 3 3 8.1 45.93 12.0 1/30 3.5 0 0 0.0 1/31 50 3.5 4.1 1 0 0.0 Appendix 4-3 Daily Results in Neutralization Circuit

Neutralization with Calcium Carbonate Neutralization with Slaked Lime Filter Press Total Cake Addition of Quality of Neutralized Solution Volume of Addition of Quality of Neutralized Solution Volume of Volume Moisture Amount of Neut. pH Date Feed Neut. Time 2+ Feed Neut. Time Times Content Product CaCO3 pH Fe T-Fe Cu SedimentSediment Ca(OH)2 pH T-Fe Mn Mg Sediment Sediment (wet) m3/day g/L h mg/L mg/L mg/L g/L t/day m3/day g/L h mg/L mg/L mg/L g/L t/day Times/day m3/day % t/day 2/1 100 3.5 2.1 3.17 N.D. 543 40.48 1 7.9 0.4 27.00 2 5.7 45.07 8.5 2/2 100 3.5 2.1 3 2 5.8 41.89 8.9 2/3 100 3.5 2.1 1 1 2.7 32.75 4.5 2/4 90 3.5 2.3 3.09 N.D. 246 53.00 1 1 2.8 44.83 4.2 2/5 100 3.5 2.1 3.97 N.D. 142 55.76 3 7.62 N.D. 2 5.5 46.54 8.1 2/6 100 3.5 2.1 3.40 N.D. 500 31.56 2 7.73 N.D. 12.00 2 5.4 47.34 7.9 2/7 100 3.5 2.1 3.52 N.D. 162 25.08 4 3 8.1 49.70 11.6 2/8 100 3.5 2.1 4.43 N.D. 196 72.48 3 2 5.2 48.94 7.5 2/9 100 3.5 2.1 1 2 5.6 47.18 8.2 2/10 100 3.5 2.1 1 2 5.9 46.00 8.7 2/11 100 3.5 2.1 3.56 N.D. 341 63.04 1 1 3.0 45.62 4.5 2/12 100 3.5 2.1 3.45 N.D. 558 67.20 3 3 8.8 46.13 13.0 2/13 100 3.5 2.1 3.79 N.D. 357 102.00 2 3 9.9 45.94 14.7 4-56 2/14 100 3.5 2.1 3.98 N.D. 243 80.20 1 3 8.1 46.19 12.0 2/15 100 3.5 2.1 3.48 N.D. 352 2 3 8.5 45.38 12.6 2/16 100 3.5 2.1 3 2 5.8 44.53 8.7 2/17 100 3.5 2.1 2 3 9.2 51.32 13.0 2/18 80 3.5 2.6 3.87 N.D. 300 51.00 2 1 2.9 60.89 3.8 2/19 50 3.5 4.1 0 0 0.0 0.0 2/20 60 3.5 3.4 3.74 N.D. 743 75.00 0 7.71 27.00 2 5.9 45.03 8.8 2/21 70 3.5 2.9 3.80 N.D. 114 114.00 0 3 8.8 48.45 12.7 2/22 90 3.5 2.3 4.02 N.D. 527 120.00 2 3 8.4 48.91 12.1 2/23 90 3.5 2.3 3 3 8.9 50.41 12.7 2/24 90 3.5 2.3 3 3 8.5 52.41 11.9 2/25 90 3.5 2.3 4.48 N.D. 59 60.96 1 2 5.9 48.66 8.5 2/26 90 3.5 2.3 3.63 N.D. 114 60.00 1 2 5.8 48.16 8.4 2/27 0 0 0 0.0 0.0 2/28 70 3.5 2.9 1 1 2.5 46.91 3.7 Appendix 4-3 Daily Results in Neutralization Circuit

4-57 3/15 100 3.5 2.1 5 4 11.3 52.35 15.8 3/16 100 3.5 2.1 4 5 14.0 50.25 20.0 3/17 100 3.5 2.1 3 2 5.8 50.09 8.3 3/18 100 3.5 2.1 3.49 N.D. 315 86.00 2 7.08 21.0 28.00 2 5.6 49.53 8.0 3/19 100 3.5 2.1 3.98 N.D. 310 74.00 3 7.38 0.9 25.00 4 11.2 47.23 16.4 3/20 110 3.5 1.9 3.40 N.D. 222 58.00 2 8.42 0.7 23.00 3 8.7 48.73 12.6 3/21 110 3.5 1.9 3.57 N.D. 181 40.00 3 1 2.5 48.76 3.6 3/22 110 3.5 1.9 3.73 N.D. 148 28.00 1 7.54 1.1 22.00 2 5.3 48.28 7.7 3/23 110 3.5 1.9 1 0 0.0 0.0 3/24 110 3.5 1.9 1 0 0.0 0.0 3/25 70 3.5 2.9 3.83 N.D. 108 35.00 2 1 2.7 51.02 3.8 3/26 90 3.5 2.3 3.31 N.D. 722 30.00 1 1 2.8 51.67 3.9 3/27 100 3.5 2.1 3.59 N.D. 517 40.00 1 1 3.0 54.55 4.1 3/28 110 3.5 1.9 4.11 N.D. 261 0 1 2.5 51.83 3.5 3/29 110 3.5 1.9 1 2 5.3 50.09 7.6 3/30 110 3.5 1.9 1 2 5.3 47.63 7.7 3/31 90 3.5 2.3 2 2 5.2 48.95 7.5 Appendix 4-3 Daily Results in Neutralization Circuit

Neutralization with Calcium Carbonate Neutralization with Slaked Lime Filter Press Total Cake Addition of Quality of Neutralized Solution Volume of Addition of Quality of Neutralized Solution Volume of Volume Moisture Amount of Neut. pH Date Feed Neut. Time 2+ Feed Neut. Time Times Content Product CaCO3 pH Fe T-Fe Cu SedimentSediment Ca(OH)2 pH T-Fe Mn Mg Sediment Sediment (wet) m3/day g/L h mg/L mg/L mg/L g/L t/day m3/day g/L h mg/L mg/L mg/L g/L t/day Times/day m3/day % t/day 4/1 100 3.5 2.1 2.59 305 43.08 2 0.5 1 2.5 50.37 3.6 4/2 100 3.5 2.1 3.83 111 22.40 5 0.1 5.44 2 5.9 49.85 8.4 4/3 100 3.5 2.1 4.18 60 25.16 1 2 5.8 48.76 8.4 4/4 100 3.5 2.1 3.95 111 3225 3 0.1 2 5.1 51.67 7.2 4/5 80 3.5 2.6 0 0 0.0 4/6 80 3.5 2.6 1 1 2.6 30.43 4.5 4/7 90 3.5 2.3 1 0 0.0 4/8 90 3.5 2.3 55 83 62.48 1 1 2.8 47.34 4.1 4/9 90 3.5 2.3 55 2816 55.76 4 3 8.6 50.22 12.3 4/10 110 3.5 1.9 4.91 55 59 48.80 2 7.84 0.3 4.12 2 5.6 49.37 8.0 4/11 120 3.5 1.7 3.66 55 96 59.88 2 3 8.2 48.62 11.9 4/12 120 3.5 1.7 4.39 55 58 79.52 2 4 10.7 49.49 15.4 4/13 120 3.5 1.7 3 4 10.7 48.76 15.4 4/14 120 3.5 1.7 0 2 5.4 46.88 7.9 4-58 4/15 120 3.5 1.7 2.84 55 437 32.84 1 1 2.8 47.75 4.1 4/16 120 3.5 1.7 3.25 55 160 78.64 5 6 15.2 47.15 22.3 4/17 120 3.5 1.7 3.45 55 63 55.04 3 4 10.1 45.92 15.0 4/18 120 3.5 1.7 3.40 55 55 75.08 3 4 10.7 46.10 15.8 4/19 120 3.5 1.7 3.24 55 55 31.76 4 4 11.1 47.07 16.3 4/20 120 3.5 1.7 3 2 4.1 51.88 5.8 4/21 120 3.5 1.7 3 4 10.5 50.59 14.9 4/22 120 3.5 1.7 3.97 1660 1712 54.12 2 7.75 3.0 10.12 3 8.0 51.61 11.3 4/23 120 3.5 1.7 2.42 1715 10146 15.44 2 2 5.3 51.50 7.5 4/24 120 3.5 1.7 1 3 8.1 55.95 11.0 4/25 130 3.5 1.6 3.93 111 370 52.68 0 2 5.3 34.66 8.7 4/26 130 3.5 1.6 3.85 55 96 34.36 2 7.51 0.6 1 3.0 41.04 4.6 4/27 140 3.5 1.5 5 4 11.0 49.43 15.8 4/28 140 3.5 1.5 0 3 8.2 48.51 11.9 4/29 140 3.5 1.5 3.75 333 368 21.60 1 2 5.1 48.76 7.4 4/30 140 3.5 1.5 3.66 111 220 30.64 2 3 8.0 51.93 11.2 Appendix 4-4 Periodical Analysis

pH 2+ T-Fe Cu Mn Zn Al Cd Pb As Mg Date Sample Fe g/L g/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L Feed Solution 3.49 12.31 24 81 305 162 1966 3080 Oxidized Solution

'01 Neutralized Solution with CaCO3

9/6 Neutralized Solution with Ca(OH)2 Effluent from the Model Plant Pregnant Solution from Leaching Tests Feed Solution 3.67 11.75 16.15 56 251 106 2240 0.83 0.80 2696 Oxidized Solution 2.66 5.5 10.75 124 302 127 2734 1.08 0.40 2927

'01 Neutralized Solution with CaCO3 2.78 5.1 10.2 117 301 125 2697 1.06 0.17 2909

9/12 Neutralized Solution with Ca(OH)2 Effluent from the Model Plant Pregnant Solution from Leaching Tests Feed Solution 3.29 20.418 28.8 253 704 298 3174 2.90 0.96 3807 Oxidized Solution 2.45 0.084 19.46 135 656 273 2975 3.00 0.10 3824

'01 Neutralized Solution with CaCO3 3.76 N.D. 2.293 92 750 267 1831 2.70 0.02 139800

9/20 Neutralized Solution with Ca(OH)2 Effluent from the Model Plant Pregnant Solution from Leaching Tests Feed Solution 2.88 12.87 7.9 111 377 185 2557 1.69 N.D. Oxidized Solution 2.21 0.028 8.5 97 432 202 2824 2.04 -

'01 Neutralized Solution with CaCO3 3.22 N.D. 0.4 84 480 186 2212 2.20 -

9/26 Neutralized Solution with Ca(OH)2 Effluent from the Model Plant Pregnant Solution from Leaching Tests Feed Solution 10.62 16.95 28 321 122 1580 1.40 0.22 9.7 Oxidized Solution 2.19 0.028 14.92 145 520 337 2706 1.60 0.03 7.7

'01 Neutralized Solution with CaCO3 3.24 N.D. 0.4 122 503 250 2240 1.60 0.04 0.3

10/4 Neutralized Solution with Ca(OH)2 8.65 N.D. 0.001 N.D. 23 1.2 2 0.47 0.06 0.02 Effluent from the Model Plant Pregnant Solution from Leaching Tests Feed Solution 3.61 21.82 21.9 152 699 269 3310 1.66 0.90 27.3 Oxidized Solution 2.25 0.028 12.5 68 507 179 3198 1.68 0.01 15.7

'01 Neutralized Solution with CaCO3 2.55 0.028 4.3 63 463 176 2895 1.68 0.03 10.6

10/10 Neutralized Solution with Ca(OH)2 Effluent from the Model Plant Pregnant Solution from Leaching Tests Feed Solution 3.02 19.58 35.3 81 517 175 4949 1.19 0.43 20.8 Oxidized Solution 2.26 0.028 15.7 115 541 180 4497 1.11 0.02 12.9

'01 Neutralized Solution with CaCO3 3.52 N.D. 0.83 82 572 170 2650 1.71 0.07 0.3

10/16 Neutralized Solution with Ca(OH)2 Effluent from the Model Plant Pregnant Solution from Leaching Tests Feed Solution 3.54 17.7 19.4 77 556 484 3580 1.73 0.79 Oxidized Solution 2.27 0.028 17.5 117 742 471 4169 3.41 0.02

'01 Neutralized Solution with CaCO3 3.23 N.D. 0.398 83 656 361 2723 2.61 0.02

10/24 Neutralized Solution with Ca(OH)2 8.17 N.D. N.D. N.D. 38 3.6 79 1.60 0.04 Effluent from the Model Plant Pregnant Solution from Leaching Tests

4-59 Appendix 4-4 Periodical Analysis

pH 2+ T-Fe Cu Mn Zn Al Cd Pb As Mg Date Sample Fe g/L g/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L Feed Solution 3.29 26.27 32.4 99 1310 291 5600 1.00 1.7 58 5900 Oxidized Solution 1.91 0.001 18.3 161 1050 262 5890 1.10 1.2 36 6150

'02 Neutralized Solution with CaCO3 4.71 N.D. 0.415 4.9 732 121 16 0.80 0.7 N.D. 5250

3/11 Neutralized Solution with Ca(OH)2 8.2 N.D. N.D. N.D. 185 0.2 N.D. 0.09 0.6 N.D. 4050 Effluent from the Model Plant Pregnant Solution from Leaching Tests Feed Solution 3.21 8.3 9.8 71 212 144 1834 1 1.2 7.9 3545 Oxidized Solution 1.76 N.D. 7.49 75 285 157 2110 0.8 <0.1 4.2 4138

'02 Neutralized Solution with CaCO3 3.73 N.D. 0.15 56 359 127 723 0.8 <0.1 0.7 4635

3/22 Neutralized Solution with Ca(OH)2 7.53 N.D. N.D. <1 36 <1 4 <0.1 <0.1 10 1814 Effluent from the Model Plant Pregnant Solution from Leaching Tests Feed Solution 3.44 8.85 11.23 62 314 157 1864 0.6 1.1 4 4547 Oxidized Solution 1.95 N.D. 8.13 83 348 154 2352 1.7 4.8 0.5 4551

'02 Neutralized Solution with CaCO3 4.11 N.D. 0.26 49 404 118 480 1.8 0.1 15.2 3650

3/28 Neutralized Solution with Ca(OH)2 Effluent from the Model Plant Pregnant Solution from Leaching Tests Feed Solution 3.47 24.9 30 129 465 357 4678 0.8 0.4 11 7789 Oxidized Solution 2.09 0.11 7.89 54 342 177 2732 0.7 <0.1 0.7 4686

'02 Neutralized Solution with CaCO3 3.95 0.11 3.22 27 420 138 522 0.7 0.1 0.3 3647

4/4 Neutralized Solution with Ca(OH)2 8.05 N.D. 0.06 <1 123 <1 <1 <0.1 <0.1 0.3 2285 Effluent from the Model Plant Pregnant Solution from Leaching Tests Feed Solution 3.07 8.3 9.64 125 285 132 1858 0.5 <0.1 9.9 3633 Oxidized Solution 1.97 N.D. 8.93 88 335 187 2886 0.7 <0.1 0.7 5065

'02 Neutralized Solution with CaCO3 3.66 N.D. 0.1 53 402 151 943 0.7 <0.1 0.4 5373

4/11 Neutralized Solution with Ca(OH)2 Effluent from the Model Plant Pregnant Solution from Leaching Tests Feed Solution 3.04 12.17 12.38 45 322 190 2243 0.7 <0.1 6.6 5362 Oxidized Solution 1.98 N.D. 8.66 92 459 257 3056 1.2 <0.1 0.8 6221

'02 Neutralized Solution with CaCO3 3.4 N.D. 0.02 80 443 203 2208 1.2 0.1 1.4 5679

4/18 Neutralized Solution with Ca(OH)2 Effluent from the Model Plant Pregnant Solution from Leaching Tests Feed Solution 2.62 11.8 12.72 81 306 188 2318 1.2 <0.1 5.5 4383 Oxidized Solution 2.4 0.11 9.3 119 446 247 2711 1.2 <0.1 0.5 5815

'02 Neutralized Solution with CaCO3 3.93 0.11 0.37 94 500 209 1176 1.2 <0.1 0.2 6266

4/25 Neutralized Solution with Ca(OH)2 8.5 N.D. N.D. <1 18 <1 <1 <0.1 <0.1 <0.1 2075 Effluent from the Model Plant Pregnant Solution from Leaching Tests Feed Solution Oxidized Solution

Neutralized Solution with CaCO3

Neutralized Solution with Ca(OH)2 Effluent from the Model Plant Pregnant Solution from Leaching Tests

4-60

Photo4-1 Flask Culture

Photo4-2 100L Culture

4-61

Photo4-3 10m3 Culture

Photo4-4 Oxidation Tank Culture

4-62

Photo4-5 Making the Bacterial Carrier with Calcium Carbonate

Photo4-6 Demonstration Test – Bacterial Oxidation Tank

4-63

Photo4-7 Demonstration Test - Flocculation Tank and Bacterial Sludge Recovering Tank

Photo4-8 Demonstration Test – Supply of Calcium Carbonate

4-64

Photo4-9 Demonstration Test – Calcium Carbonate Neutralization Tank

Photo4-10 Demonstration Test - Filter Press Cake Discharge

4-65

Photo4-11 Demonstration Test - Filter Press Cake Carryout

Photo4-12 Demonstration Test – 1) Feed Solution, 2) Oxidized Solution Tank A, 3) Tank B, 4) Tank C, 5) Bacterial Sludge Recovering Tank Solution, 6) Neutralized Solution with Calcium Carbonate, 7) Neutralized Solution with Slaked Lime

4-66

Photo4-13 Demonstration Test – 1) Bacterial Oxidized Sediment, 2) Calcium Carbonate Neutralized Sediment, 3) Slaked Lime Neutralized Sediment

Photo4-14 Demonstration Test – Filter Press Cake

4-67

Photo4-15 Demonstration Test - Storage Area of Filter Press Cake

Photo4-16 Demonstration Test – 1) Effluent from the Model Plant, 2) Leaching Plant, 3) Pregnant Solution from Leaching Plant

4-68

Photo4-17 Leaching Tests Using the Treated Solution and Oxidized Solution from the Model Plant

Photo4-18 Leaching Tests Using the Treated Solution and Oxidized Solution from the Model Plant

4-69

５．Design of Full Scale Solution Treatment Plant ５．Design of Full Scale Solution Treatment Plant

5.1 Prerequisites for Design

5.1.1 Size of the Plant Currently, volume of the waste solution from the leaching step of Ovalle plant is around 250m3/day corresponding to about 6,000 t/month of crude ore. As the installed capacity of the plant is now 14,000t/month, which will bring about 600m3/day of the waste solution when fully operated. As a matter of fact, however, crude ore supply for the operation has declined recently due to lower price of Cu as shown in Figure 5-1, 8,000t/month of the ore supply is expected at most for the time being, if some price incentives were given to the suppliers. Considering the recent situation plant design was made in two different levels of monthly throughput, one corresponds to the maximum treatment at the leaching step, 14,000t/month, and another is 8,000t/month, which is practically more realizable. The volume of the waste solution to be treated is estimated as shown in Table 5-1.

Monthly ore treatment (t/month) Cu metal price ¢ /lb

16,000 160

14,000 140

12,000 120 /lb)

10,000 100 ¢

8,000 80

6,000 60

4,000 40 Cu metal price (

Monthly ore treatment (t/month) 2,000 20

0 0 1994 1995 1996 1997 1998 1999 2000 2001 Jan. Jan. Jan. Jan. Jan. Jan. Jan. Jan. Period

Figure 5-1 Cu Metal Price vs. Monthly Ore Treatment

5-1 Table 5-1 Volume of Waste Solution to be Treated Monthly ore tretment Volume of Waste Solution

Current situation 6,000 t/month 250 m3/day

Case 1 8,000 t/month 330 m3/day

Case 2 14,000 t/month 600 m3/day

5.1.2 Specification of the Waste Solution Ferrous ion concentration in the waste solution to be fed to the treatment plant considerably fluctuates from min. 7.9 to max. 32.93g/L, averaged 17.02g/L (refer to Chap. 4). But it is unlikely to last such lower or higher level for a long time and is usually averaged in the oxidizing tanks. Thus, the mean value, 17.02g/L is taken for the design of the treatment plant. As for the other heavy metal ions, the values obtained from the basic test results are employed as shown in Table 5-2.

Table 5-2 Specification of Waste Solution (g/L)

pH Fe2+ T-Fe Cu Mn Zn Al

3.3 17.02 20.66 0.108 0.507 0.208 2.77

5.1.3 Oxidation Velocity As oxidation velocity, 1.0g/L/h is employed as the results of the demonstration tests.

5.1.4 Volume of Sediment From the test results, volume of sediment was 8.54m3/day, or 12.46wet-t/day, when 100m3/day of waste solution was fed to the plant. Average moisture content of the sediment is 47.5%.

5.1.5 Process Flow From the test results, it was confirmed that the process flow in the model plant was completely effective for the waste solution treatment. Further, according to leaching tests with use of the treated or oxidized solution, the best result was obtained when this solution was mixed by 36% in volume with the original leaching solution. This means it would be better to leave ferric ions a little without neutralization for leaching use. Moisture removed with filtered cake is estimated as follows from the tonnage and moisture content of the cake, that is, 12.46 wet-t/day ×0.475= 5.92m3/day. Accordingly, 5.92m3 of water is discharged out of 100m3 of daily feed solution. This supposedly prevents excessive concentration of heavy metals and could lead to elimination of pH

5-2 adjusting step with slaked lime in the design of full scale plant. Outline of the process flow is illustrated in Figure 5-2.

Waste solution (From Leaching plant)

Oxidizing Tank Nutrient

Flocculation tank Flocculants

Bacteria collector

Neutralizing tank Lime stone

A part of the oxidized waste solution is sent back directly Filter press to the leaching plant.

Filtrate tank

Treated soltion (To Leaching plant)

Figure 5-2 Process Flow of Fullscale Plant

5.1.6 Capacity of the Model Plant This model plant was originally designed to treat the solution, of which specification is shown in Table 5-3. Concentration of ferrous ion is down now to around 17g/L, nearly half level of the original.

Table 5-3 Specification of Feed Solution for Model Plant Design (g/L)

pH Fe2+ T-Fe Cu Mn Zn Al

3.7 30 30 0.26 0.97 0.24 9.7

Total volume of the filtered cake is also reduced to 12.46wet-t/day, from about 31.5 wet-t/day, originally designed. This allows more capacity of the major equipment like oxidation tanks and filter press than originally designed, 100m3/day. Thus, the model plant could increase its

5-3 capacity substantially by comparatively simple modification if only the oxidation tanks and filter press are fully operated. Then, the maximum capacity of the existing tanks and filter press are estimated based upon the demonstration test results at the model plant.

(1) Capacity of the oxidizing tanks Total volume of the tanks are 172m3. By deducting hold up volume of air, actual volume is 172/1.1 = 156.4m3. Further, by deducting circulating volume of bacteria sludge, real volume for the solution would be 156.4×4/5 =125m3. With these figures (ferrous concentration and oxidation velocity), treatment capacity of the tanks are estimated as follows. 125÷17.02 / 1＝7.35m3/hr＝176m3/day

(2) Capacity of the filter press The filter press installed in the model plant is now handling slurry pulp from oxidation, neutralization and pH adjustment steps together in two hours. Working cycle is now set as follows. Pressure feeding 60 min Compression 20 min Frame opening and others 40 min Total 120 min

Because of smaller volume of sediment than before, concentration of slurry pulp is lowered and this will result in higher oxidation velocity. On the contrary, as the necessary solution volume for one cycle of filter operation is increased, pressure feeding time shall remain the same 60 min. Compression time could be shortened because this pulp is well filtered but at least 10 min. are required including other blowing throughout the compression step. Frame opening etc. are all mechanical works and remain the same 40 min. Thus, one cycle time is shortened to 110 min. from present 120 min. For prevention of clogging, filter cloth has to be washed once a day. This will take another 40 min. and then, this press can operate 12.7 rounds a day as follows. {(24×60)-40}/110=12.7Batch/day Currently, 8.54m3 of filtered cake is obtained, when 100m3 of waste solution is daily treated. Effective volume of the press is 3.677m3 per one round when thickness of cake is 40mm. Actual thickness will be about 35mm due to compression and the corresponding filter volume is 3.2m3 per batch. This results in 8.54/3.2 = 2.7 rounds a day. Then, capacity of the filter press will be enough, 100/2.7×12＝444m3/day As the result of the above discussion, 176m3 of oxidation capacity will be the maximum for the treatment of the waste solution in this model plant. Regarding the other facilities, discussion was made if each one can meet the above capacity

5-4 level. The results are summarized in Table 5-4. Colored items in the Table are to be replaced for larger capacity.

Table 5-4 Necessary Modification in the Model Plant Model plant Remodeling point ITEM Equipment Name Power No. Specification of Equipment Q'ty Specification of Equipment (kw) Oxidizing process Type : Vertical cylinder There is no change. Waste water There is no problem because there is a dwell T1 Capacity : 5m3 1 receiver tank time of 40min for amount 176m3/day of the Material : PE waste solution. Type : Centrifugal pump Necessary having to change equipment It is assumed the ability to amount 3 Waste solution Capacity : 84L/min×20mH 176m /day of the waste solution. P1 1.5 1 pump Therefore, piping and the change of the flow Contact surface with solution Material : instrument are needed as 123L/min×20mH SUS316,SCS14 ×2.2kw and the pump change. Vertical cylinder with internal Type : baffle Capacity : 57.3 m3 T2 Oxidizing tank 3 There is no change. Material : FRP Dimension : 3750φ×5900H Type : Vertical cylinder There is no change. 3 Capacity : 0.43 m There is no problem because there is a dwell T3 Flocculation tank 1 3 Material : FRP time of 3.5min for amount 176m /day of the waste solution. Dimension : 800φ×1300H Type : Propeller Agitator for M1 Contact surface with solution 0.2 1 There is no change. flocculation tank Material : SUS316 Type : Thickener There is no change. Dimension : 3300φ×2500H The settling velocity becomes 0.86m/H for T4 Bacteria collector 0.75 1 amount 176m3/day of the waste solution. Material : FRP There is no problem though the impurity of Accessories : Rake the supernatant water is forecast. Type : Roots blower There is no change. 30 B1 Oxidizing blower Capacity : 14.85 m3/min×7000mmAq 1 Because the oxidizing air is supplied to the 0.2 sectional area of the oxidation tank. Material : FC etc. Vertical cylinder with internal Type : There is no change. baffle The amount of the repetition of the bacteria Bacterial-sludge Capacity : 1.8 m3 mud becomes 44m3/day=31L/min when T5 1 storage tank assuming amount 176m3/day of the waste Material : FRP solution. Therefore, the dwell time Dimension : 1300φ×1650H becomes 58min, and there is no problem. Agitator for Type : Paddle M2 Bacterial-sludge Contact surface with solution 1.5 1 There is no change. Material : storage tank SUS316 Type : Centrifugal pump Bacterial-sludge P2 Capacity : 50L/min×20mH 1.5 1 There is no change. return pump Contact surface with solution Material : FC+R/L Type : Electric Actuator Slurry feeder for DF1 Stroke : 60mm 0.08 1 There is no change. oxidation tank Material : PVC

5-5 Model plant Remodeling point ITEM Equipment Name Power No. Specification of Equipment Q'ty Specification of Equipment (kw) Type : Centrifugal pump Bacterial-sludge P3 Capacity : 1200L/min×40mH 22 1 There is no change. feed pump Contact surface with solution Material : FC+R/L Type : Vertical cylinder

3 Nutrient dissolving Capacity : 0.5 m There is no change. T6 1 tank Material : FRP Running frequency of once/day is increased. Dimension : 860φ×1150H Type : Propeller Agitator for nutrient M3 Contact surface with solution 0.2 1 There is no change. dissolving tank Material : SUS316 Type : Vertical cylinder

3 Nutrient storage Capacity : 0.75 m T7 1 There is no change. tank Material : FRP Dimension : 980φ×1250H Type : Metering pump There is no change. Because the amount of addition of nutrient Nutrient addition Capacity : 450mL/min becomes about 600mL/min, and becomes P4 0.2 1 pump insufficient the pump ability, the sulfuric Contact surface with solution Material : acid addition pump not used now is used in PVC,PTFE parallel. Type : Vertical cylinder

3 Flocculant Capacity : 0.62 m There is no change. T8 1 dissolving tank Material : FRP Running frequency of once/day is increased. Dimension : 920φ×1200H Agitator for Type : Propeller M4 flocculant Contact surface with solution 0.2 1 There is no change. Material : dissolving tank SUS304 Type : Vertical cylinder

3 Flocculant storage Capacity : 0.93 m T9 1 There is no change. tank Material : FRP Dimension : 1050φ×1350H

Type : Metering pump There is no change. Flocculant addition The amount of addition of coagulant P5 Capacity : 850mL/min 0.2 1 pump becomes 762mL/min, and satisfies the Contact surface with solution Material : ability. PVC,PTFE Type : Vertical cylinder

3 Sulfuric acid Capacity : 0.5 m T10 1 No use storage tank Material : FRP Dimension : 860φ×1150H Type : Propeller Agitator for sulfuric M5 Contact surface with solution 0.2 1 No use acid storage tank Material : SS+R/L Type : Metering pump Sulfuric acid Transfers and diverts to the nourishment P6 Capacity : 500mL/min 0.2 1 addition pump medicine addition pump. Contact surface with solution Material : PVC,PTFE

5-6 Model plant Remodeling point ITEM Equipment Name Power No. Specification of Equipment Q'ty Specification of Equipment (kw) Neutralizing

process Vertical cylinder with internal Type : baffle There is no change. There is no problem because the Capacity : 9.5 m3 T11 Neutralizing tank 1 concentration of the heavy metal have been Material : FRP reduced by half, too though the dwell time is 78min. Dimension : 1650φ×5150H

Type : Screw feeder There is no change. Because it is 3.5t/day even if the maximum, Capacity : 825kg/h 1.5 F1 Neutralizer feeder 1 the amount of use of the calcium carbonate 0.75 Material : SS does not have the problem from demonstration test result. Accessories : Air blaster，Bag filter Vertical cylinder with internal Type : baffle Neutralizer Capacity : 0.82 m3 T12 1 There is no change. re-pulping tank Material : FRP Dimension : 900φ×1600H Agitator for Type : Paddle M6 Neutralizer Contact surface with solution 0.4 1 There is no change. Material : re-pulping tank SUS304 Type : Centrifugal pump

P7 Neutralizer pump Capacity : 50L/min×20mH 3.7 1 There is no change. Contact surface with solution Material : FC+R/L Type : Electric Actuator Slurry feeder for DF2 Stroke : 60mm 0.08 1 There is no change. Neutralizing tank Material : PVC Type : Roots blower There is no change. B2 Neutralizing blower Capacity : 1.0 m3/min×6000mmAq 3.7 1 The neutralizing air is supplied to the sectional area of the neutralizing tank. Material : FC etc. Vertical cylinder with internal There is no change. Type : baffle Running frequency of the filter press for 3 Capacity : 17.3 m3 amount 176m /day of the waste solution becomes about 5 times/day. Therefore, T13 Slurry storage tank 1 Material : FRP there is no problem though the amount of the waste solution of the filter press one Dimension : 2800φ×3400H batch becomes about 35m3, becomes running divided into two times. Type : Paddle Agitator for Slurry There is no change. M7 Contact surface with solution 15 1 storage tank Material : SUS316 Type : Centrifugal pump Neutralizing-sludge There is no change. P8 Capacity : 1200L/min×40mH 22 1 feed pump Contact surface with solution Material : FC+R/L Type : Automatic type

FP1 Filter press Capacity : Filtration area 203 ㎡ 5.5 1 There is no change. Filterplate PP，Bed FC+R/L Material : Dripping pan SUS316 Compressor for Type : Reciprocate CP1 11.0 1 There is no change. blowing out Capacity : 1230L/min

5-7 Model plant Remodeling point ITEM Equipment Name Power No. Specification of Equipment Q'ty Specification of Equipment (kw) Receiver tank for Type : Vertical cylinder There is no change. RT1 blowing air 1

Capacity : 3000L Multiple stage centrifugal Type : pump P9 Washing pump Capacity : 140L/min×200mH 15.0 1 There is no change. Material : SUS304,SCS13 etc. Type : Vertical cylinder T14 Filtrate tank Capacity : 8 m3 1 There is no change. Material : PE Necessary having to change equipment The filtrate amounts become about 32m3 by Type : Centrifugal pump one time, and this pump needs the ability of 1200L/min which corresponds to the press fit pump because Filtrate tank is not Transportation sufficient as the buffer is needed in the P10 pump after Capacity : 100L/min×20mH 2.2 1 above-mentioned filtrate-tank capacity. neutralization Moreover, because the pH adjustment process became unnecessary, this pump sends treated solution back directly to the Contact surface with solution leeching plant. Material : SUS316,SCS14 Therefore, the change in piping is needed as 1200L/min×45mH×22kw pump changes. Type : Vertical cylinder Storage tank after T15 Capacity : 3 m3 1 There is no change. washing Material : PE Type : Centrifugal pump Return pump after P11 Capacity : 15L/min×27mH 1.5 1 There is no change. washing Contact surface with solution Material : SUS316,SCS14 Type : Vertical cylinder T20 Washing water tank Capacity : 3 m3 1 There is no change. Material : PE pH Adjustment The pH adjustment process becomes

process unnecessary in the full scale plant. Incidental

equipment Centrifugal pump with Type : receive tank P15 Water supply unit Capacity : 1.1 m3 0.4 1 There is no change. Material : Tank-FRP、Pump-SUS304

Compressor for Type : Reciprocate CP2 0.4 1 There is no change. instrumentation Capacity : 45L/min×7kg/cm2

5.1.7 Necessary Treatment Capacity for New Facilities According to the above discussion, in 5.1.6, the existing model plant can be modified to treat up to 176m3 of the solution per day with no major change. This means the new facilities to be installed should be sufficient if they were able to treat less volume than listed in table 5-1 by 176m3/day.

5-8 Case 1 : 8,000t-ore/month 154 m3/day (corresponding to the maximum ore supply, currently possible) Case 2 : 14,000t-ore/month 424 m3/day (corresponding to the installed capacity of the leaching plant)

In the following section 5.2, design is outlined in each case.

5-9 5.2 Outline of Full Scale Plant Design

5.2.1 Case 1 (corresponding to the maximum ore supply, currently possible) In this case, required capacity to be newly installed is 154m3/day as stated in 5.1.7. (total solution volume to be treated : 330m3/day). As for a major equipment, filter press, the existing one has already sufficient capacity and can be placed with no difficulty. Accordingly in this case, modification of the existing model plant was mainly studied. The following discussions are on this modification policy.

(1) Study on Major Equipment Required capacity of each machine is studied below. 1) Oxidizing tanks Required volume of the oxidation tanks is estimated with 25% of bacteria sludge circulation and 10% of air hold up. 330/24×17.02×1.25×1.1＝322m3 As tank volume in the model plant is 172m3, 150m3 shall be added.

2) Oxidizing blower Sufficient air blower shall be set for the newly installed tanks.

3) Bacteria collecter Diameter of the existing tank in the model plant is 3.3m. When 330m3/day of the waste solution is treated, clearing speed of the solution is about 1.6m/h. The new recovery tank shall be designed to hold the speed less than 1m/h.

4) Neutralizing tank Volume of the existing tank is 9.5m3. Unless newly installed, retention time will be about 41 minutes, somewhat short. For neutralization with calcium carbonate, at least 60 minutes of retention will be required. Then, necessary volume is estimated with 5% of solution increase and 10% of air hold up. 330/24×1.05×1.1＝15.9 m3 Thus, volume of 6.4m3 shall be added with corresponding capacity of air blower.

5) Filter press As stated in 5.1.6 (2), the existing press holds 444m3/day of treatment capacity and is sufficient. 6) Storage and feeding of calcium carbonate Consumption of calcium carbonate is at most 19.7g/L or 19.7kg/m3. When 330m3 of the waste solution is daily handled, 330×19.7＝6501kg/day＝6.5t/day

5-10 The existing feeding facility of slaked lime in the model plant shall be diverted to calcium carbonate because slaked lime is not employed in the new plant.

Equipment newly installed or modified for the new solution treatment plant is listed in the following Table 5-5. (Equipment to be installed is shown with N after its number.)

Table 5-5 List of Equipment to be Installed or Modified in Case 1 ITEM Power Equipment Name Specification of Equipment Q'ty Remarks No. (kw) Oxidizing process Type : Centrifugal pump The equipment of the model P1 Waste solution pump Capacity : 230L/min×20mH 2.2 1 plant is changed. Contact surface with solution Material : SUS316,SCS14 Type : Vertical cylinder with internal baffle Capacity : 75 m3 T2-N Oxidizing tank 2 Material : FRP Dimension : 4290φ×5900H Type : Thickener Dimension : 2600φ×2500H T4-N Bacteria collector 0.75 1 Material : FRP Accessories : Rake Type : Roots blower 30 B1-N Oxidizing blower Capacity : 12.95 m3/min×7000mmAq 1 0.2 Material : FC etc. Type : Vertical cylinder with internal baffle

3 Bacterial-sludge Capacity : 1.8 m T5-N 1 storage tank Material : FRP Dimension : 1300φ×1650H Agitator for Type : Paddle M2-N Bacterial-sludge Contact surface with solution 1.5 1 Material : storage tank SUS316 Type : Centrifugal pump The press fit pump in the model Bacterial-sludge feed P3-N Capacity : 300L/min×40mH 11 1 plant pH adjustment process is pump Contact surface with solution diverted. Material : FC+R/L Neutralizing process Type : Vertical cylinder with internal baffle Capacity : 6.4 m3 T11-N Neutralizing tank 1 Material : FRP Dimension : 1350φ×5150H Type : Roots blower B2-N Neutralizing blower Capacity : 0.67 m3/min×6000mmAq 3.7 1 Material : FC etc. Type : Centrifugal pump Transportation pump P10 Capacity : 1200L/min×45mH 22 1 after neutralization Contact surface with solution Material : SUS316,SCS14

5-11 (2) Process Flow Process flow including the model plant is illustrated in Figure 5-3.

(3) Layout Layout of equipment including the model plant is shown in Figure 5-4.

5-12

5.2.2 Case 1 (corresponding to the maximum installed capacity) In this case, necessary facilities for 424m3 of solution treatment per day are studied.

(1) Study on main equipment 1) Oxidizing tanks Daily throughput is 424m3. Necessary oxidizing volume should be 424/24×17.02×1.25×1.1＝413m3

2) Oxidizing blower Maximum 0.45m3/m2 of air shall be supplied per minute. When the effective depth of the tank is 5m, it has 82.6m2 of cross section. Then, necessary output is 82.6×0.45＝37.2m3/min

3) Bacteria collector Settling velocity is set below 1.0m/h. Then, necessary diameter is √(424/24/0.7854)＝4.8mφ

4) Neutralizing tank Necessary retention time is set at 60min., increase in solution volume is 5% and hold up volume at 10%. Then, 424/24×1.05×1.1＝20.4m3

5) Filter press Existing press now in use at the model plant has a capacity of 444m3/day as described in 5.1.6. Thus, the same one is sufficient. However, tanks for feeding and filtered solution shall have enough volumes for two rounds for safety operation.

6) Storage and feeding of calcium carbonate Maximum consumption of carbonate is 19.7g/L or 19.7kg/m3. Thus, daily consumption is 19.7×424 = 8353kg/day which nearly equals to 8.4m3/day. This is fed as slurry, 20% of concentration.

The following Table 5-6 shows equipment list to be newly installed in case 2.

5-15 Table 5-6 Equipment List to be Installed in Case 2 ITEM Power Equipment Name Specification of Equipment Q'ty Remarks No. (kw) Oxidizing process Type : Vertical cylinder T1 Waste water receiver Capacity : 10 m3 1 tank Material : PE Type : Centrifugal pump

P1 Waste solution pump Capacity : 294L/min×20mH 3.7 1 Contact surface with solution Material : SUS316,SCS14 Corner tank (internal division into Type : four) T2 Oxidizing tank Capacity : 413m3 1 Material : RC+FRP/L Type : Vertical cylinder T3 Flocculation tank Capacity : 1.0m3 1 Material : FRP Type : Propeller Agitator for M1 Contact surface with solution 0.4 1 flocculation tank Material : SUS316 Type : Thickener Dimension : 4800φ×2500H T4 Bacteria collector 1.5 1 Material : FRP Accessories : Rake Type : Roots blower 75 B1 Oxidizing blower Capacity : 37.2m3/min×7000mmAq 1 0.75 Material : FC etc. Type : Vertical cylinder with internal baffle Bacterial-sludge T5 Capacity : 4m3 1 storage tank Material : FRP Agitator for Type : Paddle M2 Bacterial-sludge Contact surface with solution 3.7 1 Material : storage tank SUS316 Type : Centrifugal pump Bacterial-sludge P2 Capacity : 100L/min×20mH 1.5 1 return pump Contact surface with solution Material : FC+R/L Type : Electric Actuator Slurry feeder for DF1 Stroke : 60mm 0.08 1 oxidation tank Material : PVC Type : Centrifugal pump The press fit pump in the model Bacterial-sludge feed P3 Capacity : 300L/min×40mH 11 1 plant pH adjustment process is pump Contact surface with solution diverted. Material : FC+R/L Type : Vertical cylinder Nutrient dissolving T6 Capacity : 2.1m3 1 tank Material : FRP

5-16 ITEM Power Equipment Name Specification of Equipment Q'ty Remarks No. (kw) Type : Propeller Agitator for nutrient M3 Contact surface with solution 0.75 1 dissolving tank Material : SUS316 Type : Vertical cylinder T7 Nutrient storage tank Capacity : 3.2m3 1 Material : FRP Type : Metering pump Nutrient addition P4 Capacity : 2000mL/min 0.2 1 pump Contact surface with solution Material : PVC,PTFE Type : Vertical cylinder Flocculant dissolving T8 Capacity : 2.72 m3 1 tank Material : FRP Agitator for Type : Propeller M4 flocculant dissolving Contact surface with solution 0.75 1 Material : tank SUS304 Type : Vertical cylinder Flocculant storage T9 Capacity : 4.1m3 1 tank Material : FRP Type : Metering pump Flocculant addition P5 Capacity : 2800mL/min 0.2 1 pump Contact surface with solution Material : PVC,PTFE Neutralizing process Type : Vertical cylinder with internal baffle T11 Neutralizing tank Capacity : 20.4m3 1 Material : FRP Type : Screw feeder

Capacity : 3500kg/h 3.7 F1 Neutralizer feeder 1 Material : SS 0.75 Accessories : Air blaster，Bag filter Type : Vertical cylinder with internal baffle Neutralizer T12 Capacity : 3.5m3 1 re-pulping tank Material : FRP Agitator for Type : Paddle M6 Neutralizer Contact surface with solution 2.2 1 Material : re-pulping tank SUS304 Type : Centrifugal pump

P7 Neutralizer pump Capacity : 200L/min×20mH 3.7 1 Contact surface with solution Material : FC+R/L Type : Electric Actuator Slurry feeder for DF2 Stroke : 60mm 0.08 1 Neutralizing tank Material : PVC Type : Roots blower B2 Neutralizing blower Capacity : 2.2 m3/min×6000mmAq 7.5 1 Material : FC etc.

5-17 ITEM Power Equipment Name Specification of Equipment Q'ty Remarks No. (kw) Type : Vertical cylinder with internal baffle T13 Slurry storage tank Capacity : 75m3 1 Material : FRP Type : Paddle Agitator for Slurry M7 Contact surface with solution 55 1 storage tank Material : SUS316 Type : Centrifugal pump Neutralizing-sludge P8 Capacity : 1200L/min×40mH 22 1 feed pump Contact surface with solution Material : FC+R/L Type : Automatic type Filter press FP1 Capacity : Filtration area 203 ㎡ 5.5 1 Filter press Filterplate PP，Bed FC+R/L Material : Dripping pan SUS316 Compressor for Type : Reciprocate CP1 11.0 1 blowing out Capacity : 1230L/min Receiver tank for Type : Vertical cylinder RT1 blowing air 1 Capacity : 3000L Type : Multiple stage centrifugal pump P9 Washing pump Capacity : 140L/min×200mH 15.0 1 Material : SUS304,SCS13 etc. Type : Vertical cylinder T14 Filtrate tank Capacity : 75 m3 1 Material : PE Type : Centrifugal pump Transportation pump P10 Capacity : 400L/min×45mH 15 1 after neutralization Contact surface with solution Material : SUS316,SCS14 Type : Vertical cylinder Storage tank after T15 Capacity : 3 m3 1 washing Material : PE Type : Centrifugal pump Return pump after P11 Capacity : 15L/min×27mH 1.5 1 washing Contact surface with solution Material : SUS316,SCS14 Type : Vertical cylinder T20 Washing water tank Capacity : 3 m3 1 Material : PE Incidental equipment Type : Centrifugal pump with receive tank

P15 Water supply unit Capacity : 1.1 m3 0.4 1 Material : Tank-FRP、Pump-SUS304

Compressor for Type : Reciprocate CP2 0.4 1 instrumentation Capacity : 45L/min×7kg/cm2

5-18 (2) Process Flow Process flow including the model plant is illustrated in Figure 5-5.

(3) Layout Layout is also illustrated in Figure5-6 including the model plant.

5-19

5.3 Estimate of Installation and Operation Costs From the results of above discussion, installation and operation costs for the full scale plant are estimated below. In case 1, cost for modification of the model plant to treat 330m3/day of the waste solution is shown as installation cost. Also necessary change in the model plant to treat 176m3 a day was estimated for comparison.

5.3.1 Installation Cost Installation cost in each case is estimated respectively as shown in the following Table. （US$） The Maximum Capacity Case1 Case2 of Model plant 330m3/day 600m3/day 176m3/day Mechanical works 35,000 282,000 1,245,000 Electric works 4,000 47,000 354,000 Civil works 0 48,000 416,000 Architectural works 0 22,000 110,000 Amount 39,000 399,000 2,125,000

5.3.2 Operation Cost Operation cost in each case is estimated respectively as shown in the following Table. （US$／year） The Maximum Capacity Case1 Case2 of Model plant 330m3/day 600m3/day 176m3/day Material 67,000 126,000 228,000 Electric 26,000 38,000 83,000 Labor 40,000 40,000 40,000 Maintenance 49,000 58,000 96,000 Amount 182,000 262,000 447,000 * Material cost is based upon the following price. As for consumption, refer to the Chap. 4. Calcium carbonate : US$ 0.0589/kg Nutrient : US$ 4.61/kg Flocculant : US$ 4.428/kg * Electric charge is based on US$ 0.052/KwH. * All labor cost is based on the present cost at the model plant. * Maintenance cost is set at 3% of total installation (electric and mechanical). In case of the model plant, total installation cost was US$ 1,600,000.

5-22

６．Economical and Financial Analysis for Waste Solution Treatment ６． Economical and Financial Analysis for Waste Solution Treatment

6.1 Background and Outline of the Project At Ovalle plant, copper (Cu) precipitate is being produced from oxide Cu ores through leaching and Cu precipitation steps. This process is composed of acid leaching step of oxide Cu ore followed by Cu precipitation for iron scrap from the leached or pregnant solution. Refer to Figure 6-1, which shows the operation before this Study started. From the Cu precipitation step, when Cu is reduced or exchanged for iron scrap, waste solution with high content of iron sulfate is discharged. This solution is led to evaporation ponds, located at downstream from the plant, where moisture is evaporated with sunlight and iron sediment stays at the bottom of the pond. But part of the solution penetrate from the bottom into the soil flowing to nearby the river Ingenio, then contaminate the soil and water system surrounding the plant. To solve the contamination problem, the bottom is usually lined with waterproof materials, however, this might be insufficient at Ovalle, where earthquake or flood is possible to happen. For prevention of water pollution, this Study was aimed at installation of a model (pilot) plant for neutralization of the waste solution with help of bacteria activity. As the results of demonstration tests at the model plant, it was found that iron components contained in the solution were successfully removed as chemically stable sediment and the effluent can be returned to the previous leaching section and reused. Thus, at Ovalle plant, pollution free operation is assured for oxide Cu ore processing. Current flow diagram is illustrated in Figure 6-2, for actual oxide copper ore treatment process at Ovalle plant. On the other hand, production of Cu sulfate was started through a new circuit branched off the main Cu precipitation producing line. In stead of exchanging Cu for iron, it is extracted with

organic solvent to crystallize as CuSO4・5H2O as a saleable by-product. At the same time, the total volume of the waste solution to be treated is correspondingly reduced. In this Chapter, a feasibility study shall be made when the above model plant is scaled up for industrial use to meet the larger volume of waste solution from the leaching section. Discussion is made in the following three cases of different levels of leaching operation. Case 1 : Throughput of the leaching plant is set at 6,000 ton/month. (close to the recent operation and model plant is not scaled up)【without project】 Case 2 : Throughput of the leaching plant is set at 8,000 ton/month (maximum level of the recent operation) Case 3 : Throughput of the leaching plant is set at 14,000 ton/month (The maximum capacity) In the case 2 and 3, of which throughput is over current 6,000 ton/month level, investment is indispensable for increase in volume of waste solution. Based on the above, economical and financial analyses are proceeded utilizing both private and social evaluation process according to the “Norms and Procedures for Project Evaluation” inside ENAMI. The results of the plant examination, separately carried out in this Study, are also taken into account in the evaluation.

6-1

S&M mines

Ore collection

Ore transportation

Ore receipt/storage Ovalle Plant Limits

Ore crushing Ore sampling

Size classification Ore analysis

Coarse ore recycle

Fine ore storage

Water, Agglomeration H2SO4

Transportation

Heap padding

H SO 2 4 Acid leaching solution

Eluent, Iron Precipitation Solvent extraction Solvent makeup

Sol/liq separation Re-extrac./cristaliz.

Liq: evaporation Sol: dewatering Centrifugation

Heat drying Storage/drying

Packing

Precipitate transp.

CuSO4 transport.

Waste water infiltration Cu Refinery Client

Figure 6-1 Oxide Copper Ore Treatment Process at Ovalle Plant (Previous)

6-2 S&M mines

Ore collection

Ore transportation

Ore receipt/storage Ovalle Plant Limits

Ore crushing Ore sampling

Size classification Ore analysis

Coarse ore recycle

Fine ore storage

Water, Agglomeration H2SO4

Transportation

Heap padding

H SO 2 4 Acid leaching solution

Iron Eluent, scrap Precipitation Solvent extraction Solvent makeup

Sol/liq separation Re-extrac./cristaliz.

Sol: dewatering Centrifugation

Remnant waste Bacteria oxid./neut. Heat drying Storage/drying

Filtering Packing

Precipitate transp.

CuSO4 transport. Filtrate recycle

Sludge disposal

Waste water infiltration Cu Refinery Client

Figure 6-2 Oxide Copper Ore Treatment Process at Ovalle Plant (Actual)

6-3 6.2 Procedure for Project Approval Inside ENAMI, every project (including expansion plan of existing facilities) is discussed and planned based upon the above Norms and Procedures for submission to the Board of Directors, where its feasibility is judged technically and economically. Then, for drawing up next year’s budget, discussion is made comprehensively at COCHILCO and MIDEPLAN as illustrated in Figure 6-3. Upon approval by both organizations, it is finally approved through the Congress as national budget. Throughout the discussion, technical feasibility is confirmed by COCHILCO with use of estimated Cu price, while MIDEPLAN justifies the project in the viewpoint of possible development of natural resources evaluating the relationship with coexisting sectors. Accordingly, this model program, upon which this analysis is based, was made up for ENAMI to utilize as study data for realization of the project.

Ovalle Plant Proposal

ENAMI Refusal Board of Directors Reject Evaluation

Acceptance

Refusal COCHILCO MIDEPLAN Refusal Reject Evaluation Evaluation

Acceptance Through Ministry of Acceptance Finance

National Budget Approval at Congress

Figure 6-3 ENAMIs Projects Approval Process

6-4 6.3 Market and Production Process

6.3.1 Demand and Market

Market situation of Cu precipitate as well as Cu sulfate (CuSO4・5H2O), products from Ovalle plant, is summarized as below. (1) Cu precipitate As usual Cu grade of this product is 65～85%, further metallurgical treatment is needed in smelting process. This has higher grade than Cu concentrate but less favorable for exothermic reaction in a roasting process, the first step of usual pyrometallurgical treatment. At ENAMI smelters, Cu precipitate is added into converters (Pierce-Smith type) acting a part of temperature regulator, other than copper recovery itself. Ventanas smelter can handle 5,000 tons of Cu precipitate a year ( 1.25% of total input) , while Paipote smelter 6,000 tons totalling 11,000 tons/year for both smelters. In the year 2000, about 1,200 tons was demanded from outside ENAMI, that means the maximum consumption of this product is about 12,200 metric tons a year inside Chile. As export is unlikely, total amount is for domestic consumption only. On the other hand, Cu precipitate is being supplied by ENAMI’s oxide Cu plants, small and medium producers supported by ENAMI and other independent producers. As indicated in Figure 6-4 and Table 6-1, supply of Cu precipitate has declined as Cu price went down. Thus, the supply will be moving with Cu price in future. Figure 6-5 shows supply ratio for each producer and indicates that in the year 2000, 62% of this product is from ENAMI’s processing plants (El Salado, Taltal, Ovalle and Vallenar) and the rest, 38% is from the third party, outside suppliers. It is assumed that ENAMI plants have 11,800 dmt of production capacity a year in total considering 45% of actual rate of plant capacity utilization in 2000 (out of 11,800 dmt, Ovalle has 3,200 dmt a year). Also ore throughput of each plant is subjected to supplying capacity of surrounding mines. Thus, the rate of capacity use has been decreased at each plant as Cu price declined. On the other hand, El Salado plant is planning to introduce solvent extraction and electro- winning process (SX-EW) to produce electrolytic Cu as a final product instead of Cu precipitate. Test operation of SX-EW has already been completed on a small scale, producing electrolytic Cu (grade 99.99% or more) successfully. Considering the treatment capacity of ENAMI smelters and production cut at El Salado plant, production increase of Cu precipitate at Ovalle is practically realizable if crude ores are sufficiently supplied. In other words, 3,200 dmt of the maximum yearly production from Ovalle can be well handled at the smelters.

6-5 Table 6-1 Copper Precipitate Supply (unit: dmt) & Copper Price

1995 1996 1997 1998 1999 2000

Small scale producer 5,216 3,026 2,488 2,435 3,395 4,525

Medium scale producer 8,733 3,932 0 26 0 0

Independent producer 1,097 354 128 581 599 922

Outsider supply 15,046 7,312 2,616 3,042 3,994 5,447

ENAMIs smelter treatment 29,745 13,658 8,631 2,769 3,659 9,407

Outsider treatment 2,239 1,972 0 8,742 11,611 1,247

Total supply 31,984 15,630 8,631 11,511 15,270 10,654

LME copper cash price annual average US$/fmt 2,936.52 2,290.46 2,275.70 1,652.88 1,573.66 1,814.26 US¢/lb 133.20 103.89 103.22 74.97 71.38 82.29

Sources: 1) Copper precipitate supply: ENAMIs Annual Report, 1996, 1998 & 2000 2) Copper price: LME

40,000 3,000

30,000 2,500

20,000 2,000 dmt US$/mt

10,000 1,500

0 1,000 1995 1996 1997 1998 1999 2000

Outsider supply Total supply LME copper cash price annual average

Figure 6-4 Cement Copper Supply versus Copper Price

6-6 Table 6-2 ENAMIs Copper Oxide Ore Processing Plant Operation Results (Year 2000)

Plant Taltal El Salado Vallenar Ovalle ENAMI Total

Ore purchase dmt 55,754 116,710 32,424 61,530 266,418

Ore treatment dmt 71,155 116,710 35,397 53,173 276,435 Operation rate 49% 79% 25% 32% Installed capacity dmt 150,000 150,000 140,000 170,000 610,000

Cu precipitate supply dmt 3,082 3,452 1,067 1,390 8,991 Cu content fmt 2,455 2,901 870 1,139 7,365 Cu grade 80% 84% 82% 82% 82% Cu recovery rate 78% 78% 81% 76% 78% Calculated production dmt 2,900 2,900 2,800 3,200 11,800 capacity* * Calculations based on 2.5% ore grade, year 2000 result copper recovery rate Source: ENAMI Annual Report 2000

Ovalle Vallenar 10% 7%

El Salado Outsider 24% 38%

Taltal 21%

Figure 6-5 Cement Copper Supply Share (Year 2000)

6-7 (2) Copper sulfate (CuSO4・5H2O) Cu content of this product is 26%. Ovalle plant has 40ton of monthly production capacity and this total amount is now exported through a dealer to Rumania. Ex-work price at the plant

is 98 ¢ /lb of Cu (US$561.73/dmtof CuSO4). On the other hand, production cost is around

US$280/dmtof CuSO4. Currently, 100 tons/month is demanded by the customer. Worldwide demand of this product is supposed to be around 200,000 tons a year, of which three quarters are for agricultural use, pesticide. Number of producers4) worldwide amounts to one hundred or more supposedly. Other uses are various, like electrolyte in copper refining, coating agent in Cu plating, activator in Zn flotation, etching agent of Cu plate, anti-rust paint, glass coloring and others.

6.3.2 Production Capacity of Ovalle Plant Installed capacity of Ovalle is 170,000 dmt per year or about 14,000 dmt per month to produce 3,200 dmt of Cu precipitate a year. However, current rate of capacity utilization is around 43% due to decrease of ore supply, down to around 6,000 dmt of monthly throughput caused by recent lower Cu price. As a middle term program, ENAMI aims at around 8,000 dmt of crude ore supply (rate of capacity use : 57%). Secondary leaching of waste rocks from the primary treatment is also carried out accounting for 48% of crude ore amount.

Production of CuSO4・5H2O is now 40mt per month (Cu grade 26%). This is equivalent to 600mt/month of crude ore, 10% of total feed amount, based upon 92% of Cu recovery in the branched circuit, 82.2% of recovery in the leaching step and 2.3% of averaged Cu grade in crude ores respectively.

6.3.3 Crude Ores and Consumption Materials (1) Crude ores All of crude ores are supplied by surrounding 40～50 small mines. As stated before total amount decreased due to recent lower level of Cu price. In ENAMI Annual Report, 2000, ore reserves of oxide Cu are reported as follows.

Table 6-3 ENAMI Own Mining Rights Ore Reserves (Oxide Copper Mineral) Area Exploration Proven Reserves Cu grade Possible Total Zones (mt) (%) Reserves (mt) (mt) North 67 1,311,208 2.08 510,874 1,822,082 Central 7 423,575 1.85 828,453 1,252,028 Total 74 1,734,783 2.02 1,339,327 3,072,110 Source: ENAMI Annual Report 2000

From this Table, if current input amount, 276,435 dmt/year is kept constantly at Ovalle, possible operation would last 6.3 years based on the proven reserves and 11.1 years if possible reserves are added.

6-8 As ore purchasing costs are paid by the Support Funds for small scale mines of ENAMI, Ovalle plant is not directly affected financially.

(2) Consumption materials For production of Cu precipitate, sulfuric acid and iron scraps are indispensable. Sulfuric acid is supplied by Paipote and Ventanas smelters through ground transportation. Acquisition price at Ovalle is US$ 39.00/mt. Also at Ovalle, iron scraps are US$ 57.00/mt. As iron scraps, industrial wastes like used machines and parts are effectively utilized and that contributes to the system of “Material Circulating Economy”. Table 6-4 shows consumption and unit cost at Ovalle. Table 6-4 Complementary Supply Materials: Oxide Copper Ore Processing Plant Material Item Unit Primary leaching Secondary leaching Sulfuric Acid Consumption US$ 361,880 44,752 Processed ore dmt 69,126 32,860 Unit cost US$/dmt 5.24 1.36 Iron scrap Consumption US$ 69,751 6,750 Processed ore dmt 69,126 32,860 Unit cost US$/dmt 1.01 0.21 Source: Ovalle Plant

On the other hand, for waste solution treatment from the leaching step, neutralization reagents, flocculants and bacteria nutrients are required. Price and consumption at Ovalle are shown in Table 6-5. Table 6-5 Complementary Supply Materials: Waste Water Treatment Plant Reagent Purchase cost Consumption Unit cost （US$/kg）（kg/m3）（US$/ m3） Calcium carbonate 0.0589 17 1.00 Floculant 4.248 0.005 0.0266 Nutrient 4.61 0.0025 0.0115

6.3.4 Supply Materials and Repair Cost Costs of supply materials and repair are listed in Table 6-6 (actual results in 2001).

Table 6-6 Factory Supplies and Maintenance Costs: Oxide Copper Ore Processing Plant Item Unit Fix cost rate Ore reception Crushing Cu Precipitate Plant Sulfate Cu Primary Secondary Plant leaching leaching Safety devices US$ 50% 135 150 Parts US$ 20% 2,436 12,343 25,222 9,346 Expendables US$ 0% 69 356 1,003 209 Maintenance cost US$ 85% 2,847 10,177 47,900 200 12,979 Other fix costs US$ 100% 1,834 72 4,666 337 Other variable costs US$ 0% 452 1,834 1,519 Total fix cost US$ 4,809 11,267 50,425 170 13,238 Total variable cost US$ 2,964 13,666 29,885 30 9,633 Total cost US$ 7,774 24,932 80,310 200 22,871 Processed ore quantity dmt 69,318 69,318 69,125 32,860 193 Fix unit cost US$/dmt 0.07 0.16 0.73 0.0052 68.73 Variable unit cost US$/dmt 0.04 0.20 0.43 0.0009 50.01 Total unit cost US$/dmt 0.11 0.36 1.16 0.0061 118.75 Source: Ovalle Plant *Ore reception and crushing costs calculated proportionally to oxide copper ore processed rate, due to common operation with sulfate copper ore process.

6-9 6.3.5 Utility Costs of utilities are shown in Table 6-7. (actual results in 2001)

Table 6-7 Utilities: Oxide Copper Ore Processing Plant Item Unit Ore receptionCrushing Cu Precipitate Plant Sulfate Cu Primary Secondary Plant leaching leaching Fix utility cost US$ 1,615 Variable utility cost US$ 4,154 262 10,128 3,977 1,237 Total utility cost US$ 4,154 262 11,743 3,977 1,237 Processed ore quantity dmt 69,318 69,318 69,125 32,860 193 Fix unit cost US$/dmt 0.00 0.00 0.02 0.00 0.00 Variable unit cost US$/dmt 0.06 0.004 0.15 0.12 6.42 Total unit cost US$/dmt 0.06 0.004 0.17 0.12 6.42 Source: Ovalle Plant

*Ore reception and crushing costs calculated proportionally to oxide copper ore processed rate, due to common operation with sulfate copper ore process.

6.3.6 Plant Location and Engineering In this Report, these costs should be included in the technology transfer and handled as sunk cost excluded from this financial analyses. 6.3.7 Indirect Administrative Costs In this item, costs of management, travel, information processing, chemical analyses etc. are included. Table 6-8 shows the indirect administrative costs at Ovalle plant (actual results in 2001).

Table 6-8 Administration Overhead Costs: Oxide Copper Ore Processing Plant Item Unit Ore receptionCrushing Cu Precipitate Plant Sulfate Cu Primary Secondary Plant leaching leaching Fix administration costs US$ 90,199 23,945 314,581 304 Variable administration costs US$ 47 13,794 576 Total US$ 90,246 23,945 328,375 576 304 Processed ore quantity dmt 69,318 69,318 69,125 32,860 193 Fix unit cost US$/dmt 1.30 0.35 4.55 0.00 1.58 Variable unit cost US$/dmt 0.0007 0.00 0.20 0.02 0.00 Total unit cost US$/dmt 1.30 0.35 4.75 0.02 1.58 Source: Ovalle Plant

*Ore reception and crushing costs calculated proportionally to oxide copper ore processed rate, due to common operation with sulfate copper ore process.

6.3.8 Labor Costs Labor costs at Ovalle are divided into direct labor and contract labor cost. Table 6-9 shows actual results in 2001. Labor costs are subject to 2% increase a year according to the “Investment Standards” inside ENAMI.

6-10 Table 6-9 Human Resource Costs: Oxide Copper Ore Processing Plant Item Unit Ore Crushing Cu Precipitate Plant Sulfate Cu reception Primary Secondary Plant leaching leaching Fix direct H.R. cost US$ 16,511 10,181 59,582 Variable direct H.R. cost US$ 2,061 1,626 7,861 Fix contracted H.R. cost US$ 6,726 3,937 34,026 11,337 Variable contracted H.R. cost US$ 27,112 28,601 161,342 43,464 17,609 Total US$ 52,410 44,346 262,811 43,464 28,946 Processed ore quantity dmt 69,318 69,318 69,125 32,860 193 Fix unit cost US$/dmt 0.34 0.20 1.35 0.00 58.86 Variable unit cost US$/dmt 0.42 0.44 2.45 1.32 91.43 Total unit cost US$/dmt 0.76 0.64 3.80 1.32 150.29 Source: Ovalle Plant

*Ore reception and crushing costs calculated proportionally to oxide copper ore processed rate, due to common operation with sulfate copper ore process.

6.3.9 Depreciation As actual depreciation in 2001, US$ 4,856 for ore reception step, US$ 30,317 for crushing and US$ 84,246 for Cu precipitation step are counted respectively. As the former two steps are in common with sulfide Cu ores, these amounts should be distributed by multiplying 52%, ratio of oxide Cu ores and then, depreciation for oxide ores amounts to US$ 102,526 in total. This indicates that for maintenance and improvement of oxide plant facilities, this level of annual investment (around US$ 100,000) would be necessary and allowable. On the other hand, depreciation is excluded from this analysis because scrap values have no influences upon the results. Thus, the analyses are performed under the condition that investment on the solution treatment plant (in case of 2 and 3 before-mentioned), major parts of initial investment, shall have no scrap values any more fifteen years after realization. 6.3.10 Waste Solution Treatment Plant Plant investment and operation costs of waste solution treatment, now under consideration, are summed up in Table 6-10 for each level of treatment amount. Estimated volume of circulated solution to the primary leaching is also shown in the Table.

Table 6-10 Waste Water Treatment Plant Performance and Operating Cost Ore Processing Capacity 6,000dmt/month 8,000dmt/month 14,000dmt/month Waste water generation 250m3/day 330m3/day 600m3/day Waste water treatment capacity 176m3/day 330m3/day 600m3/day Treated water recycling capacity 158m3/day 297m3/day 540m3/day Fix assets investment (US$) 39,000 399,000 2,125,000 Operating costs (US$/year) 182,000 262,000 447,000

6.4 Executing Program For the scale up plan of the current waste solution treatment (model) plant, the plant life shall be set at 15 years at this moment. Adding one year for construction period, yearly program shall be made for 16 years in total as a project term. Although the positive ore reserves last no more

6-11 than 11.1 years, as stated in item 1) Crude ores of this section, these are assumed to steadily increase as necessary. On the other hand, plant closure is not taken into consideration because legal regulations are uncertain yet and will not affect the plant scale to be compared. Ovalle processing plant is defined as “Custom beneficiation plant”, which adds some value to the crude ores through treatment, and its income and expenditure are evaluated based upon the internal rules of ENAMI. The evaluation methods for oxide Cu ores are as follows.

6.4.1 Commission for Ore Procurement This is evaluated by ENAMI management for procuring crude ores from surrounding mines and expressed as the following formula. mo IC = CTc * QC = 9,178.67 US$/month

CTc : commission for ore procurement (US$ 1.28/dmt)

QC : ore tonnage procured (7,170.836 dmt)

6.4.2 Commission for Oxide Ore Crushing This is evaluated by ENAMI for crushing works and expressed as follows. mo ICh = CTch * QCh = 13,696.30 US$/month

CTch : commission for ore crushing (1.91 US$/dmt)

QCh : ore tonnage crushed (7,170.836 dmt)

6.4.3 Commission for Oxide Ore Processing This is evaluated for oxide ore processing from crude material to Cu precipitate and expressed as follows. mo Ib = ( CTf + CTv ) * Qb = 67,587.70 US$/month

CTf : fixed commission for processing (8.10 US$/dmt)

CTv : variable commission for processing (4.87 US$/dmt)

CTv = CTb * Lm

CTb : standard of fluctuating commission (1.965)

Lm : soluble Cu grade (2.480 %)

Qb : ore tonnage processed (5,209.794 dmt)

6.4.4 Valuation of Cu Precipitate This is evaluated by defining the standards of metallurgical (operation) results as follows : Cu recovery rate : 77.68%, Cu grade in precipitate : 75.5% and rate of Cu losses : 4%. Other factors, Cu price, smelting and refining charges etc. are subjected to current situation. Expression is as follows. (1) Valuation standards R m VPS = [ fCu-P ( PCu – C Cu ) Fc ( 1 – p Cu / 100 ) – ( Ws-P * Mf ) ] = 117,017.98 US$/month

fCu-P : Cu quantity contained in Cu precipitate (100.365 fmt)

6-12 PCu : Cu (market) price (68.2180 US¢/lb) R C Cu : Cu refining charge (7.62 US¢/lb) R Rb if PCu < 80 US¢/lb → C Cu = C Cu + 0.1 ( PCu – 80) R Rb if PCu [ 80 US¢/lb , 100 US¢/lb ] → C Cu = C Cu R Rb if PCu > 100 US¢/lb → C Cu = C Cu + 0.1 ( PCu – 100) Rb C Cu : standard of Cu refining charge (8.80 US¢/lb)

Fc : conversion factor (22.0462 US$-lb/US¢-mt) m p Cu : rate of Cu loss (4.00 %)

Ws-P : Cu precipitate production (132.934 dmt)

Mf : smelting charge (88.00 US$/dmt) Also Cu recovery rate and Cu grade in precipitate are set as standards.

RCu: Cu recovery rate (77.68 %)

LCu-P: Cu grade in precipitate (75.50 %) (2) Valuation of actual results R m VPR = [ fCu-P ( PCu – C Cu ) Fc ( 1 – p Cu / 100 ) – ( Ws-P * Mf ) ] = 112,400.79 US$/month

fCu-P : Cu quantity contained in Cu precipitate (95.320 fmt)

PCu : Cu (market) price (68.2180 US¢/lb) R C Cu : Cu refining charge (7.62 US¢/lb) R Rb if PCu < 80 US¢/lb → C Cu = C Cu + 0.1 ( PCu – 80) R Rb if PCu [ 80 US¢/lb , 100 US¢/lb ] → C Cu = C Cu R Rb if PCu > 100 US¢/lb → C Cu = C Cu + 0.1 ( PCu – 100) Rb C Cu : standard of Cu refining charge (8.80 US¢/lb)

Fc : conversion factor (22.0462 US$-lb/US¢-mt) m p Cu : rate of Cu loss (4.00 %)

Ws-P : Cu precipitate production (111.878 dmt)

Mf : smelting charge (88.00 US$/dmt) CU recovery and grade, actual results in Feb., 2001 are as follows.

RCu: Cu recovery rate (73.78 %)

LCu-P: Cu grade in precipitate (85.20 %) (3) Difference of both valuations Difference in standards and actual results is net monthly balance at the plant.

VN = VPR – VPS = 112,400.79 US$/month – 117,017.98 US$/month = -4,617.19 US$/month On the other hand, ore purchasing terms between ENAMI and suppliers (for crude ores and Cu precipitates), are described below.

6.4.5 Purchasing Price of Oxide Ores Oxide Cu ores are evaluated and purchased based upon the following conditions. (1) Standard price R m Vb = { [ FC (PCu – C Cu) (Lp / 100) (1 – p Cu / 100) ] – Mf } (R / 100) (Lm / Lp) –

[ Cf + Lm (Ca + Cch) ] = 7.4125 US$/dmt

6-13 FC : conversion factor (22.0462 US$-lb/US¢-mt)

PCu : subsidized Cu price (70.8470 US¢/lb) R C Cu : Cu refining charge (7.8847 US¢/lb) R Rb if PCu < 80 US¢/lb → C Cu = C Cu + 0.1 ( PCu – 80) R Rb if PCu [ 80 US¢/lb , 100 US¢/lb ] → C Cu = C Cu R Rb if PCu > 100 US¢/lb → C Cu = C Cu + 0.1 ( PCu – 100) Rb C Cu : standard of Cu refining charge (8.80 US¢/lb)

Lp : Cu grade in precipitate (75.50 %) m p Cu : rate of Cu loss (4.00 %)

Mf : Cu smelting charge (88.00 US$/dmt) R : Cu recovery rate (77.68 %)

Lm : Cu grade in crude ore (2.50 %)

Cf : standard of general commission (11.29 US$/dmt)

Ca : commission for acid consumption (1.354 US$/1%)

Ca = PH2SO4 ( R / 100 ) ( CH2SO4 / 100 )

PH2SO4 : unit price of acid (35.00 US$/mt)

CH2SO4 : consumption of acid (4.98 kg/kg)

Cch : commission for iron scrap consumption (0.6110 US$/1%)

Cch = Pch ( R / 100 ) ( Cch / 100 )

Pch : unit price of iron scrap (65.00 US$/mt)

Cch : consumption of iron scrap (1.21 kg/kg) (2) Surplus grade commission : This is paid for crude ores, of which Cu grade is above 2.5%. R m Ve = { [ FC (PCu – C Cu) (Lp / 100) (1 – p Cu / 100) ] – Mf } (R / 100) (1 / Lp) –

(Ca + Cch) = 7.4810 US$/%-dmt (3) Deviation in acid consumption : This is ratio of actual acid consumption to standard. b PPH2SO4 = Ca / C a = 0.2719 US$/%-dmt b C a : Standard consumption of acid (4.98 kg/kg) (4) Subsidy for stabilizing price D FE = [ (FC * A 872 * 96.00) (R / 100) ] / 10,000 = 2.3268 US$/%-dmt D A 872 : ENAMI statement No. 872 (14.1530 US¢/lb) S D if P Cu – PCu < 0 → A 872 = 0 S D S if P Cu – PCu ≥ 0 → A 872 = P Cu – PCu S P Cu : stabilized price (85.00 US¢/lb)

6.4.6 Purchasing of Cu Precipitate Cu precipitate procured at ENAMI smelters from the third party is evaluated as follows. (1) Standard price R m Vb = [ FC (PCu – C Cu) (Lp / 100) (1 – p Cu / 100) ] – Mf = 778.1625 US$/dmt

FC : conversion factor (22.0462 US$-lb/US¢-mt)

6-14 PCu : Cu subsidized price (70.8470 US¢/lb) R C Cu : Cu refining charge (7.8847 US¢/lb) R Rb if PCu < 80 US¢/lb → C Cu = C Cu + 0.1 ( PCu – 80) R Rb if PCu [ 80 US¢/lb , 100 US¢/lb ] → C Cu = C Cu R Rb if PCu > 100 US¢/lb → C Cu = C Cu + 0.1 ( PCu – 100) Rb C Cu : standard of Cu refining charge (8.80 US¢/lb)

Lp : Cu grade in precipitate (65.00 %) m p Cu : rate of Cu loss (4.00 %)

Mf : Cu smelting charge (88.00 US$/dmt) (2) Commission for surplus Cu grade : paid for higher grade precipitate (over 65% Cu) R m Ve = FC (PCu – C Cu) (1 / 100) (1 – p Cu / 100) = 13.3256 US$/%-dmt (3) Subsidy for stabilizing price : D FE = [ (FC * A 872 * 96.00) ] / 10,000 = 2.9954 US$/%-dmt D A 872 : ENAMI statement No. 872 (14.1530 US¢/lb) S D if P Cu – PCu < 0 → A 872 = 0 S D S if P Cu – PCu ≥ 0 → A 872 = P Cu – PCu S P Cu : stabilized Cu price (85.00 US¢/lb) Financial and economic analyses on Ovalle plant are made as follows based upon the actual operation results in 2001. These analyses include the achievement derived from Chap. 3. “Examination on Ovalle plants” and also estimation of scale up program by dividing operation costs into fixed and variable items. Further for information, value analyses are carried out on processing crude ore through Cu ingot metal to understand the special situation at Ovalle as a “Custom processing plant”. Thus, value adding process is estimated including before and after Ovalle plant to know the rate of cost assignment born to the plant. Overall operation program for oxide ore processing is illustrated in Figure 6-6, “Oxide ore processing at Ovalle plant (operating program)”.

6-15

S&M mines

Ore collection

Ore transportation

Ore receipt/storage Ovalle Plant Limits

Ore crushing Ore sampling

Size classification Ore analysis

Coarse ore recycle

Fine ore storage

Water, Agglomeration H2SO4

Transportation

Heap padding

H SO 2 4 Acid leaching solution

Iron Eluent, Precipitation scrap Solvent extraction Solvent makeup

Sol/liq separation Re-extrac./cristaliz.

Sol: dewatering Centrifugation

Bacteria oxid./neut. Heat drying Storage/drying

Filtering Packing

Precipitate transp.

CuSO4 transport. Filtrate recycle

Sludge disposal

Cu Refinery Client

Figure 6-6 Oxide Copper Ore Treatment Process at Ovalle Plant (Future)

6-16 6.5 Financial Analysis First, cash flow analyses were carried out on three levels of monthly throughput of crude ore as follows. For detailed data, refer to ANNEX attached to this Report. Case 1 : Monthly throughput 6,000 dmt/month : current level of operation, scale up program of the waste solution treatment is unnecessary.（Without-project） Case 2 : Monthly throughput 8,000 dmt/month Case 3 : Monthly throughput 14,000dmt/month As this analysis is much affected with fluctuation of Cu price, sensibility analysis was taken on three levels of the price, that is, 80, 92 and 102¢ /lb, according to the “Norms and Procedures for Project Evaluation” of ENAMI. Now that taxation system on Ovalle is under national control and profit-loss balance is not carried forward to the following term, this analyses are made within business matter only excluding financial effects of depreciation. Effect of fund management is also excluded.

On the other hand, production of CuSO4・5H2O is fixed at current level of 40mt/month and also treatment of secondary leaching is at current level of 48%(to the primary) to avoid influence by fluctuation. From the results of cash flow, discounted cash flow analysis is carried out with use of 14% of discount rate (designated in the “Norms and Procedures for Project Evaluation”) to estimate “Net Present Value (NPV)” and “Internal Return Rate (IRR)” as well. These results are summarized in Table 6-11.

Table 6-11 Financial Analysis Results

Project case Cu price Initial investment Cash cost* NPV14% IRR (US¢ /lb) (thousand US$) (US¢ /lb) (thousand US$) (%) Without project 68.2180 139 63.03 -3,484 irrational

6,000dmt ore processing 68.2180 139 59.43 -2,998 irrational 6,000dmt ore processing 80.00 139 59.43 -2,913 irrational 6,000dmt ore processing 92.00 139 59.43 -2,818 irrational 6,000dmt ore processing 102.00 139 59.43 -2,740 irrational

8,000dmt ore processing 68.2180 499 52.70 -3,114 irrational 8,000dmt ore processing 80.00 499 52.70 -2,999 irrational 8,000dmt ore processing 92.00 499 52.70 -2,868 irrational 8,000dmt ore processing 102.00 499 52.70 -2,761 irrational

14,000dmt ore processing 68.2180 2,225 43.93 -3,776 irrational 14,000dmt ore processing 80.00 2,225 43.93 -3,567 irrational 14,000dmt ore processing 92.00 2,225 43.93 -3,331 irrational 14,000dmt ore processing 102.00 2,225 43.93 -3,137 irrational

* First year Cash Cost (depreciation cost subtracted operating cost【unit: US¢ /lbCement copper Cu content】)

As can be seen from the Table, all the cases are financially infeasible. By increasing throughput level from 6,000 to 14,000dmt per month, cash cost is reduced by about 26% from US¢ 59.43 to US¢ 43.93/lb enjoying scale-up merit, however, still insufficient to balance profit and loss. Major problem lies in operation costs brought from the treatment plant of waste

6-17 solution. Further, effect of the increase of Cu price is so small under current evaluation process that no direct advantages are available. Thus, if Cu price is up from US¢ 68.2180/lb by about 50% to 102.00¢ /lb, effect on NPV comes out only about 9～17% (9, 11 and 17% in Case 1, 2 and 3 respectively) much less on IRR, meaningless. Refer to the Figures attached in ANNEX. On the other hand, according to Cu purchasing terms by ENAMI, standard price for oxide ores is US ¢ 17.31/lb and smelting and refining charges (standard) are US ¢ 3.18/lb and 8.80 respectively. With use of these prices, the above-mentioned cash costs in Ovalle are summarized as indicated in Table 6-12.

Table 6-12 Metallic Copper Process Value Added Analysis 6,000dmt/month 8,000dmt/month 14,000dmt/month Cu ore basic cost (US¢ /lb) 17.31 Ovalle Plant Cash Cost (US¢ /lb) 59.43 52.70 43.93 Smelting charge (US¢ /lb) 3.18 Refining charge (US¢ /lb) 8.80 Total (US¢ /lb) 88.72 81.99 73.22

Total amount listed in the above Table corresponds to overall cash flow in ENAMI’s Cu production. Although this procedure is different from normal method of financial analysis, it is explained that the financial feasibility throughout ENAMI depends upon the operation scale at Ovalle plant proportionally. In other words, the prerequisite condition to keep Ovalle plant feasible is that Cu price is over US¢ 88.72/lb at 6,000 ton/ month level of operation and over US¢ 73.22/lb at 14,000 ton/month respectively. Another factor to be noticed is difference in smelting charge that is imposed on plant products. Compared to US¢ 1.00/lb-cu (smelting charge×Cu grade in concentrate ×Cu recovery × conversion factor) imposed on Cu concentrate, US¢ 3.18/lb-cu is imposed or charged in case of Cu precipitate despite higher grade of Cu. The difference of US¢ 2.18/lb-cu has not a little influence on production of Cu precipitate. On the other hand, it is clear from this analysis that Cash Cost attributed to Ovalle is as high as 60～67% of all.

6.6 Economic Analysis These analyses are based upon shadow price factor, designated by social analytic evaluation in the “Norms and Procedures for Project Evaluation” of ENAMI, application of social discount rate, outside economic effects brought by environmentally friendly operation at Ovalle and entire quantitative analysis within the community including the ore supplying miners. The shadow price is designated to multiply any income of foreign currency by 1.04 and also to multiply any labor costs for semi-skilled workers by 0.65 as conversion factors respectively.

Thus, sales income by exporting CuSO4・5H2O to Rumania, and labor costs for semi-skilled workers are amended in the following analyses.

6-18 The results of the financial analyses, before mentioned, are estimated with DCF process applying 10% of social discount rate (designated in the Norms and Procedures for Project Evaluation). Further, the external economy are quantitatively estimated with restoration costs of environmental liabilities, improvement effects of water quality in the El Ingenio river resulted from investment on a industrial waste solution treatment plant and also improvement of soil as well. As for the restoration costs of the environment, total investment was estimated at around US$ 1,251,300 as previously stated in the item 4.2-3 of the Interim Report. The details are listed in Table 6-13 below. Among them, investments that have direct relation to the El Ingenio river, are US$ 222,200 of waterproof works inside the evaporation ponds, US$ 168,200 of reclamation works of accumulated iron sediments inside the ponds as well as US$ 70,400 of restoration works against nature destruction. Accordingly, investment that relates to this economic analysis amounts to US$ 460,800 in total.

Table 6-13 Environmental Liability Improvement Works Investment Classification* Investment (US$)** Inside operation area 1,180,900 Pollution prevention measures 1,012,700 ・Acid leaching heap extension works 90,500 ・Acid leaching waste ore disposal 700,000 ・Evaporation pond waterproofing works 222,200 Material recycle measures ・Evaporation pond accumulated ferrous sulfate recovery and disposal 168,200 Environmental damage restoration Contaminated soil restoration, nature deterioration remediation 70,400 Total 1,251,300 *”Environmental Accounting System introduction Guideline (Former Environment Agency Environmental Accounting System Establishment Discussion Group March 2000 compiletion)” suggested classification. ** Source: ENAMI. “Situación Ambiental en Planta Ovalle con Uso de la Capacidad Instalada. Valorización del Plan General de Actividades”. June 2000. (Ovalle Plant environmental situation on installed capacity. General activities plan valorization.)

6.6.1 External Economy by Environmental Improvement The external economy, stated in this section, are economic evaluation of improved situation after the environmentally friendly operation is completed at Ovalle plant. For quantitative evaluation, there are two types of approach methods, objective and subjective one. In this Report, Hedonic approach, one of estimation methods for real estate, a type of subjective approach, is applied. According to SAG (Servicio Agricola y Ganadero), the basin of the river Ingenio, the main stream of the Ovalle, is the second important economic area in the Ⅳ region next to the Elqui basin. In the region of the Ingenio, many kinds of vegetables like avocados, oranges, vines etc, are cultured and meadows are widely extended. The situation is quite similar in the upper stream area from Ovalle plant. It is said that the unit value of land considerably differs between the upper and lower stream area from the plant due to soil and water contamination caused by the plant operation. According to SAG, compared to the land price of upper stream area , around

6-19 CH$ 3,000,000 (Chilean pesos) /Ha, the price of lower stream stays as low as CH$ 800,000/Ha, lower by about 70% than the former. A land value theory explains that if the prices of two neighboring areas differ, it is caused by the difference in productivity per unit area or by some environmental factor apart from price. It also says that current productivity of land should be reflected in the price. Accordingly, the outside economic effects by environmental restoration are estimated with following conditions. • Increase in unit land value : by CH$ 2,200,000/Ha (US$ 4,000/Ha, exchange rate : CH$ 550/US$) • Area, currently contaminated : 200Ha (estimated by survey of affected land from the evaporation pond at Ovalle to the monitoring point, M-7, in this Study [5km lower stream from the plant], refer to Figure 6-7). • Area that will be possibly affected by spread of contamination if no restoration takes place : 400Ha (estimated by survey of land from M-7 point to the junction of the El Ingenio river with the Limari, refer to Figure 6-7). Under these conditions, outside economic effects by restoration amount to US$ 4,000/Ha × 200Ha =US$ 800,000. Outside negative effect in case that no restoration takes place (negative effects by spread of contamination) : US$ 4,000/Ha×(400Ha + 200Ha) = US$ 2,400,000

6-20

El Ingenio River

Recoleta Dam

Ovalle Plant

Monitoring Point M-7 Hurtado River

Grande River

Limarí River Paloma Dam

Legend: N

Actually impacted area estimation Potentially influenced area estimation

Figure 6-7 El Ingenio River Impacted Area Estimation

6-21 6.6.2 External Economy including near-by ore supplying miners This effect is enjoyed by the surrounding miners supported with ENAMI’s promotion program. This corresponds to amount of money paid the miners by ENAMI on ore purchasing terms after deducting total costs born by the miners to deliver their ores to Ovalle. As for the costs born by the miners, SERNAGEOMIN reports that the minimum level inside the Ⅳ region, where Ovalle plant is located, is CH$ 5,600/mt. This value is taken for the following estimation after multiplying the wholesale price index13) and converting with the average currency rate in Dec.,2001. That is, CH$ 5,600/mt×(177.69÷118.82) ÷CH$ 544.63/US$ = US$ 15.38/dmt Under these conditions, outside economic effects including nearby miners are quantitatively estimated as shown in Table 6-14.

Table 6-14 Externalities for Surrounding Small and Medium Mines Cu price Ore purchase quantity Ore purchase quantity Ore purchase quantity (US¢ /lb) 6,000dmt/month 8,000dmt/month 14,000dmt/month (thousand US$/year) (thousand US$/year) (thousand US$/year) 62.2180 0 0 0 80.00 0 0 0 92.00 122 162 284 102.00 411 548 960

6.6.3 External Economy by Water Reuse Introduction of the waste solution treatment results in effective reuse of treated solution as new water resource. Thus, a large amount of water that has been evaporated so far, can be used again by circulating to the leaching step. If water consumption at Ovalle decreased, the plant does not enjoy cost saving directly because of local irrigation right. However, this can also be evaluated as an external economy in the viewpoint of water resource saving. Inside the river basin of the Limari, a branch river of the Ingenio, there exists 50.000Ha of farmland that takes irrigation water from the river as well as from three systems of reservoir dam (total volume of 1,000,000,000m3, Paloma : 750,000,000m3, Cogoti : 150,000,000m3 and Recoleta : 100,000,000m3). Also, 80,000 of Ovalle resident rely upon the river for daily water. In this region the irrigation right can be traded freely and willingness to pay for water is also settled voluntarily. According to the research results by the World Bank, US$ 2.47/m3 per year is expected from the trade of irrigation right on the river Limari. This value was estimated with added value in agricultural use along the river with use of the currency rate of CH$ 403/US$ in June, 1993. If the current rate (Dec., 2001) was employed, it corresponds to US$ 2.95/m3 a year. With use of this value, the outside effect by water saving is estimated as shown in Table 6-15. Table 6-15 Externalities due to Water Recycling Savings Ore processing capacity 6,000dmt/month 8,000dmt/month 14,000dmt/month Waste water generation 250m3/day 330m3/day 600m3/day Treated water recycling capacity 176m3/day 297m3/day 540m3/day Water savings volume 158m3/day 217m3/day 190m3/day Externality (thousand US$/year) 168 230 202

6-22 As can be seen from the Table 6-15, in case that crude ore amount is 6,000dmt/month, total treated solution could be reused and the corresponding volume is saved from new input. In case of 8,000 and 14,000dmt/month, total treated solution should be offset by increased water consumption in the processing plant.

6.6.4 Summary of External Economy (Externalities) Each of the external economy, above mentioned, can be used individually for making summarized “social Cash Flow” analysis because they are not overlapped each other. For the detailed data, refer to the attached program recorded in ANNEX of this Report. • Net present value of the external economy by land restoration, which covers 200Ha of contaminated area along the river El Ingenio (from the pond at Ovalle to the monitoring point M-7, 5km downstream from the plant). • External economy including ore supplying mines brought by trading activity between the plant and miners. • External economy resulted from water saving at Ovalle by circulating reuse. These effects are summarized characteristically in Table 6-16 on yearly base.

Table 6-16 Externalities Resumes Externality Year 0 Years 1 to 15 (thousand US$) (thousand US$/year) Benefits due to environmental improvements 800,000 0 Benefits for surrounding S&M mines* 6,000dmt/month, 92.00US¢ /lb 0 122 6,000dmt/month, 102.00US¢ /lb 0 411 8,000dmt/month, 92.00US¢ /lb 0 162 8,000dmt/month, 102.00US¢ /lb 0 548 14,000dmt/month, 92.00US¢ /lb 0 284 14,000dmt/month, 102.00US¢ /lb 0 960 Benefits due to water recycling savings** 6,000dmt/month 0 168 8,000dmt/month 0 230 14,000dmt/month 0 202 * Benefit value diverges depending on ore process level and copper price. ** Benefit value diverges depending on ore process level.

Table 6-17 Economic Analysis Results

Project case Cu price Initial investment Cash cost* NPV10% IRR (US¢ /lb) (thousand US$) (US¢ /lb) (thousand US$) (%) 6,000dmt ore processing 68.2180 600 54.31 -776 53.68% 6,000dmt ore processing 80.00 600 54.31 -672 47.44% 6,000dmt ore processing 92.00 600 54.31 370 irrational 6,000dmt ore processing 102.00 600 54.31 2,671 irrational

8,000dmt ore processing 68.2180 960 48.13 -92 irrational 8,000dmt ore processing 80.00 960 48.13 51 24.92%

6-23 Project case Cu price Initial investment Cash cost* NPV10% IRR (US¢ /lb) (thousand US$) (US¢ /lb) (thousand US$) (%) 8,000dmt ore processing 92.00 960 48.13 1,445 153.14% 8,000dmt ore processing 102.00 960 48.13 4,516 407.54%

14,000dmt ore processing 68.2180 2,686 39.92 105 11.10% 14,000dmt ore processing 80.00 2,686 39.92 364 13.68% 14,000dmt ore processing 92.00 2,686 39.92 2,814 33.88% 14,000dmt ore processing 102.00 2,686 39.92 8,197 72.64%

* First year Cash Cost (depreciation cost is subtracted from operating cost【unit: US¢ /lbCement copper Cu content】)

In case of 6,000dmt/month of ore throughput, negative values are shown through NPV evaluation when Cu price is below US¢ 80.00/lb resulting in socially infeasible project. If the price rose above US¢ 92.00/lb, NPV value turned positive, while by IRR evaluation method, shown as irrational. This is caused by that investment for large scale of solution treatment is unnecessary and profit-loss exceeds break-even point when Cu price is over US¢ 92.00/lb. In other words, realization of land restoration is the key factor for continuous plant operation in this case. If Cu price rose above US¢ 92.00/lb, the operation exceeds the bottom line turning into socially feasible. In case of 8,000dmt/month, positive value was obtained through NPV evaluation when Cu price is above US¢ 80.00/lb and also extraordinary high value in IRR analysis. This was brought by comparatively large advantage in the earlier period and good profit-loss balance. Thus, if the price is over US¢ 80.00/lb, it is socially feasible. In case of 14,000dmt/month, full scale operation of the current capacity, the operation is far above the bottom line turning into socially feasible by enjoying scale up merit. NPV values are all positive in the range of Cu price between US¢ 68.2180～102.00/lb, and in IRR analysis, values larger than the social discount rate, 10% are given. Of course, as Cu price rose, situation turns still better. Further, through the study of investment recovery period, it will be possible within two years when Cu price is US¢ 102.00/lb and within thirteen years at most with US¢ 68.2180/lb of the price. Refer to the attached Figures in ANNEX of this Report.

6.7 Economic Effects for the Third Party (Cu Precipitate Producers) For the purpose of judging the price evaluation, which is diffused inside ENAMI, estimation was made on added value of Cu precipitate for comparison, when produced by the hand of a private miner or the third party by itself. Prerequisite conditions are as follows. • The added value, above mentioned, is defined as the difference of delivered price to ENAMI between crude material and Cu precipitate product after processing. • In this case, Cu grade of the crude ore is fixed at 2.50% and acid consumption in leaching 4.98kg/kg-ore. These are the standard level ENAMI usually pays for. • Cu recovery rate is fixed at 77.68%. Others are all fixed at the same conditions as employed in the Standard Evaluation designated by ENAMI management.

6-24 Under these conditions, unit price of crude ore (converted to per Cu dmt in precipitate), purchasing terms of the precipitate at ENAMI and the above defined “added value” of the precipitate (Cu 65～85%) are estimated in four levels of Cu price respectively. The results are shown in Table 6-18 and Figure 6-8, “Added value of Cu precipitate in different levels of Cu grade and price”. For comparison of these results to Cash Cost born by Ovalle plant, the latter is shown at the lower part of the Table. These results show that the added values of Cu precipitate stay between US$ 150～720/dmt, lower than Cash Cost born by Ovalle plant, US$ 780～1,240/dmt. In other words, the third party or outside producers of Cu precipitate can not enjoy the added value when produced it by themselves. Nor can they enjoy increase in Cu price due to unbalanced price system between crude ore and Cu precipitate (From the figure, added value line goes down as Cu price up). Accordingly, as long as the price evaluation by ENAMI is valid, it is more favorable for the outside producers to sell oxide ores as they are or before producing Cu precipitate. In other words, added value to precipitate is economically disadvantageous.

6-25 Table 6-18 Outside Copper Precipitate Producer Value Added Calculation Sheet

Cu price (US¢ /lb) 68.218 80 92 102 Oxide copper ore Unit Basic price US$/dmt 7.41 12.07 17.19 21.21 Cu grade premium US$/%-dmt 7.48 9.34 11.39 13.00 Acid savings premium US$/%-dmt 0.27 0.27 0.27 0.27 Cu price subside US$/%-dmt 2.33 0.32 0.00 0.00

Ore unit cost US$/dmtCement Cu 381.69 621.29 885.05 1,092.29

Copper Precipitate Basic price US$/dmt 778.16 933.90 1,105.34 1,240.05 Cu grade premium US$/%-dmt 13.33 15.72 18.36 20.43 Cu price subside US$/%-dmt 3.00 0.41 0.00 0.00

Copper Precipitate Cu grade Cu Precipitate Value Added 65% US$/dmt 396.47 312.61 220.30 147.76 70% US$/dmt 478.08 393.25 312.09 249.92 75% US$/dmt 559.68 473.88 403.89 352.08 80% US$/dmt 641.29 554.52 495.68 454.23 85% US$/dmt 722.89 635.16 587.48 556.39

Ovalle Plant Cash Cost

6000dmt/month US¢ /lbCu-content 59.43 59.43 59.43 59.43

8000dmt/month US¢ /lbCu-content 52.70 52.70 52.70 52.70

14000dmt/month US¢ /lbCu-content 43.93 43.93 43.93 43.93

6000dmt/month US$/dmt 1,579 1,579 1,579 1,579 8000dmt/month US$/dmt 1,400 1,400 1,400 1,400 14000dmt/month US$/dmt 1,167 1,167 1,167 1,167

800.00

700.00

600.00

500.00 68.218 80 400.00 92 US$/dmt 300.00 102

200.00

100.00

0.00 65% 70% 75% 80% 85% Copper Precipitate Cu Grade

Figure 6-8 Copper Precipitate Value Added per Cu Grade

6-26 6.8 Conclusion on Economical and Financial Analysis The results of the financial and economic analyses are summarized for final recommendation as follows.

6.8.1 Increase in Capacity Utilization Rate for Oxide Cu Processing Usual NPV or IRR evaluation resulted in “infeasible” in every case, however, Cash Cost are found to be remarkably reduced by increasing the rate of capacity use. On the other hand, economic analyses including outside effects resulted in feasible operation in the case of 14,000 dmt/month of ore throughput even at lower level of Cu price.

6.8.2 Increase in Stable Supply of Oxide Cu Ores For the improvement of capacity use rate, stable supply of crude ores is inevitable. For this purpose, it is necessary to tie up with any specific ore suppliers or to develop mining program by Ovalle itself, though this involves some change in the business affairs stated in the Articles of Association. On the other hand, it was understood that the cost of ore procurement is now US¢ 17.31/lb-cu, accounting for more than 20% of the total. Switching this fixed cost into variable one is an important problem. This also can be solved by performing own mining operation. Major business target of ENAMI is offering help and assistance to small and medium miners. However, under recent severe situation, in which crude ores are hardly supplied, some transformation should be discussed from its original role, “supporting system”, into new “job creating organization in regional development”. Especially, in local areas, where no economic activity is available other than mining, establishment of job creation policy for business expansion is highly recommended.

6.8.3 Scale up of Waste Solution Treatment Plant As the results of these analytical works, expansion of the waste solution plant is inevitable for treatment of total volume of the waste solution from the leaching step. Further, by circulating the treated solution from the plant to the preceding leaching step, water for industrial use can be saved as a whole. Although this has not a great economical effect on Ovalle plant, but will contribute to the outside community considerably.

6.8.4 Restoration of the Environmental Liability Contaminated soil and water caused by the past environmental carelessness have to be solved by any improvement restoration works. They are to be proceeded along with the expansion of solution treatment plant. It is expected that the inhabitants are able to extremely enjoy the results of the restoration works.

6-27 6.8.5 Increase in CuSO4・5H2O Production This production should be continued or rather increased by surveying the market, since it contributes to diversification of product and decrease in solution volume as well.

6.8.6 Study on Merchandizing of Iron Sediment Considering the specification of the iron sediments (currently final waste), if these were successfully merchandized as some kind of iron material, they could contribute greatly to diversification of the waste solution treatment plant assuring profitable operation.

6.8.7 Review of Price, Evaluation Standards etc. Considering the current situation of income and cost allotment, especially underestimated price for Cu precipitate production, it is necessary to review the predetermined Standards again taking real conditions into consideration.

The following Figure summarizes the above recommendations along with resultant advantages.

6-28

Foreign currency gain and Benefit due to waste water volume reduction

producing sulfate

copper

ENAMI

↓

Benefits due to water Ovalle Plant recycling savings for Benefits due to oxide operating water treatment plant Benefits ore demand for due to cement copper environm-

entally production increment friendly operation

Externalities El Ingenio basin inhabitants: Surrounding S&M mines: area development by their continuity and employment creation agricultural usage, landscape

improvement

Limarí River basin inhabitants: water availability due to water savings

Figure 6-9 Proposal-Benefit Interrelation

6-29 ANNEX

¾ Private : 6,000dmt/month processing / without project : Income data input sheet ¾ Private : 6,000dmt/month processing / without project : Expenditure data input sheet ¾ Private : 6,000dmt/month processing / without project : Cash flow ¾ Private : Improved 6,000dmt/month processing [Analysis Results] ¾ Private : Improved 8,000dmt/month processing [Analysis Results] ¾ Private : Improved 14,000dmt/month processing [Analysis Results] ¾ Social : Improved 6,000dmt/month processing [Analysis Results] ¾ Social : Improved 8,000dmt/month processing [Analysis Results] ¾ Social : Improved 14,000dmt/month processing [Analysis Results]

6-30 Private: 6,000dmt/month processing/without project【68.2180】

Income Data Input Sheet

Ore purchase fee 1.28 US$/dmt Purchased ore quantity 6000 dmt/month

Ore crushing fee 1.91 US$/dmt Crushed ore quantity 6000 dmt/month

Ore process fix fee 8.1 US$/dmt Ore process variable fee 4.87 US$/dmt Basic variable fee 1.965 Soluble Cu grade 2.48 ％ Processed ore quantity 6000 dmt/month for cement Cu production 5340 dmt/month for sulfate Cu production 660 dmt/month

Sulfate Cu ex-works price 98 US¢ /lbCu Sulfate Cu delivery 40 mt/month

Standard Plant statement Ovalle Plant results

Cu price 68.2180 US¢ /lb 68.2180 US¢ /lb Cu recovery rate 77.68% 77.30% Cement-Cu Cu grade 75.50% 82.90%

Cement Cu production 136 dmt/month 123 dmt/month Cement-Cu Cu content 103 fmt/month 102 fmt/month

Cu loss rate 4.00% 4.00%

Smelting charge 88.00 US$/dmt 88.00 US$/dmt Basic refining charge 8.80 US¢ /lb 8.80 US¢ /lb Refining charge 7.62 US¢ /lb 7.62 US¢ /lb

Process valorization 119,943 US$/month 120,421 US$/month

Valorization balance 478 US$/month

Legends: Red colored value: Predetermined conditions Blue colored value: ENAMI defined Standard Plant operation performance Black colored value: Calculated value

6-31 Private: 6,000dmt/month processing/without project【68.2180】

Expenditure Data Input Sheet

Fix assets investment 139,000 US$ Waste water treatment plant Cement Cu process 100,000 US$ Operating cost 182,000 US$ Sulfate Cu process 0 US$ Waste water treatment 39,000 US$

Secondary leaching rate 0.48

Complementary supply materials

H2SO4: primary leaching 5.24 US$/dmt

H2SO4: secondary leaching 1.36 US$/dmt Iron scrap: primary leaching 1.01 US$/dmt Iron scrap: secondary leaching 0.21 US$/dmt

Factory supplies & maint. Fix Variable Ore reception 0.07 US$/dmt 5,040 US$/year 0.04 US$/dmt Crushing 0.16 US$/dmt 11,520 US$/year 0.20 US$/dmt Primary leaching 0.73 US$/dmt 52,560 US$/year 0.43 US$/dmt Secondary leaching 0.01 US$/dmt 720 US$/year 0.0009 US$/dmt

Utilities Fix Variable Ore reception 0.00 US$/dmt 0 US$/year 0.06 US$/dmt Crushing 0.00 US$/dmt 0 US$/year 0.004 US$/dmt Primary leaching 0.02 US$/dmt 1,440 US$/year 0.15 US$/dmt Secondary leaching 0.00 US$/dmt 0 US$/year 0.12 US$/dmt

Administration overhead Fix Variable Ore reception 1.30 US$/dmt 93,600 US$/year 0.0007 US$/dmt Crushing 0.35 US$/dmt 25,200 US$/year 0.00 US$/dmt Primary leaching 4.55 US$/dmt 327,600 US$/year 0.20 US$/dmt Secondary leaching 0.00 US$/dmt 0 US$/year 0.02 US$/dmt

Human resource Fix Variable Ore reception 0.34 US$/dmt 24,480 US$/year 0.42 US$/dmt Crushing 0.20 US$/dmt 14,400 US$/year 0.44 US$/dmt Primary leaching 1.35 US$/dmt 97,200 US$/year 2.45 US$/dmt Secondary leaching 0.00 US$/dmt 0 US$/year 1.32 US$/dmt

CuSO4 production unit cost 280 US$/dmt

CuSO4 production quantity 40 mt/month

Legends: Red colored value: Predetermined conditions Green colored value: Ovalle Plant's year 2001 results Black colored value: Calculated value

6-32 Private: 6,000dmt/month processing/without project Cash Flow【68.2180】(1/4)

Year 0123 Unit: Dec. 2001 fix US$ Fix assets investment 139,000 100,000 100,000 100,000

Oxide ore purchase fee 92,160 92,160 92,160 Oxide ore crushing fee 137,520 137,520 137,520 Oxide ore processing fee 934,070 934,070 934,070 Cement Cu processing balance 5,740 5,740 5,740 Cu sulfate sells 269,634 269,634 269,634 Total income 1,439,124 1,439,124 1,439,124

Waste water treatment plant 182,000 182,000 182,000 Complementary supply materials 504,259 504,259 504,259

H2SO4: primary leaching 377,280 377,280 377,280

H2SO4: secondary leaching 47,002 47,002 47,002 Iron scrap: primary leaching 72,720 72,720 72,720 Iron scrap: secondary leaching 7,258 7,258 7,258 Factory supplies & Maintenance 118,111 118,111 118,111 Ore reception 7,920 7,920 7,920 Crushing 25,920 25,920 25,920 Primary leaching 83,520 83,520 83,520 Secondary leaching 751 751 751 Utilities 20,995 20,995 20,995 Ore reception 4,320 4,320 4,320 Crushing 288 288 288 Primary leaching 12,240 12,240 12,240 Secondary leaching 4,147 4,147 4,147 Administration overhead 461,542 461,542 461,542 Ore reception 93,650 93,650 93,650 Crushing 25,200 25,200 25,200 Primary leaching 342,000 342,000 342,000 Secondary leaching 691 691 691 Human resource 420,019 428,420 436,988 Ore reception 54,720 55,814 56,931 Crushing 46,080 47,002 47,942 Primary leaching 273,600 279,072 284,653 Secondary leaching 45,619 46,532 47,462

CuSO4 plant expenses 134,400 134,400 134,400 Total Expenditure 139,000 1,941,326 1,949,727 1,958,295

Annual balance (nominal) (139,000) (502,202) (510,602) (519,171) Annual balance (discounted) (139,000) (440,528) (392,892) (350,425) Accumulated balance (nominal) (139,000) (641,202) (1,151,804) (1,670,975) Accumulated balance (discounted) (139,000) (579,528) (972,420) (1,322,845)

NPV(14%) -US$3,483,980 IRR #DIV/0! Cash Cost 63.03 US¢ /lb

6-33 Private: 6,000dmt/month processing/without project Cash Flow【68.2180】(2/4)

Year 4567 Unit: Dec. 2001 fix US$ Fix assets investment 100,000 100,000 100,000 100,000

Oxide ore purchase fee 92,160 92,160 92,160 92,160 Oxide ore crushing fee 137,520 137,520 137,520 137,520 Oxide ore processing fee 934,070 934,070 934,070 934,070 Cement Cu processing balance 5,740 5,740 5,740 5,740 Cu sulfate sells 269,634 269,634 269,634 269,634 Total income 1,439,124 1,439,124 1,439,124 1,439,124

Waste water treatment plant 182,000 182,000 182,000 182,000 Complementary supply materials 504,259 504,259 504,259 504,259

H2SO4: primary leaching 377,280 377,280 377,280 377,280

H2SO4: secondary leaching 47,002 47,002 47,002 47,002 Iron scrap: primary leaching 72,720 72,720 72,720 72,720 Iron scrap: secondary leaching 7,258 7,258 7,258 7,258 Factory supplies & Maintenance 118,111 118,111 118,111 118,111 Ore reception 7,920 7,920 7,920 7,920 Crushing 25,920 25,920 25,920 25,920 Primary leaching 83,520 83,520 83,520 83,520 Secondary leaching 751 751 751 751 Utilities 20,995 20,995 20,995 20,995 Ore reception 4,320 4,320 4,320 4,320 Crushing 288 288 288 288 Primary leaching 12,240 12,240 12,240 12,240 Secondary leaching 4,147 4,147 4,147 4,147 Administration overhead 461,542 461,542 461,542 461,542 Ore reception 93,650 93,650 93,650 93,650 Crushing 25,200 25,200 25,200 25,200 Primary leaching 342,000 342,000 342,000 342,000 Secondary leaching 691 691 691 691 Human resource 445,728 454,642 463,735 473,010 Ore reception 58,069 59,231 60,415 61,624 Crushing 48,900 49,878 50,876 51,894 Primary leaching 290,347 296,153 302,077 308,118 Secondary leaching 48,411 49,380 50,367 51,375

CuSO4 plant expenses 134,400 134,400 134,400 134,400 Total Expenditure 1,967,035 1,975,949 1,985,042 1,994,317

Annual balance (nominal) (527,910) (536,825) (545,918) (555,193) Annual balance (discounted) (312,565) (278,810) (248,713) (221,876) Accumulated balance (nominal) (2,198,885) (2,735,710) (3,281,628) (3,836,821) Accumulated balance (discounted) (1,635,411) (1,914,221) (2,162,933) (2,384,809)

6-34 Private: 6,000dmt/month processing/without project Cash Flow【68.2180】(3/4)

Year 8 9 10 11 Unit: Dec. 2001 fix US$ Fix assets investment 100,000 100,000 100,000 100,000

Waste water treatment plant 182,000 182,000 182,000 182,000 Complementary supply materials 504,259 504,259 504,259 504,259

H2SO4: primary leaching 377,280 377,280 377,280 377,280

H2SO4: secondary leaching 47,002 47,002 47,002 47,002 Iron scrap: primary leaching 72,720 72,720 72,720 72,720 Iron scrap: secondary leaching 7,258 7,258 7,258 7,258 Factory supplies & Maintenance 118,111 118,111 118,111 118,111 Ore reception 7,920 7,920 7,920 7,920 Crushing 25,920 25,920 25,920 25,920 Primary leaching 83,520 83,520 83,520 83,520 Secondary leaching 751 751 751 751 Utilities 20,995 20,995 20,995 20,995 Ore reception 4,320 4,320 4,320 4,320 Crushing 288 288 288 288 Primary leaching 12,240 12,240 12,240 12,240 Secondary leaching 4,147 4,147 4,147 4,147 Administration overhead 461,542 461,542 461,542 461,542 Ore reception 93,650 93,650 93,650 93,650 Crushing 25,200 25,200 25,200 25,200 Primary leaching 342,000 342,000 342,000 342,000 Secondary leaching 691 691 691 691 Human resource 482,470 492,119 501,962 512,001 Ore reception 62,856 64,113 65,395 66,703 Crushing 52,931 53,990 55,070 56,171 Primary leaching 314,280 320,566 326,977 333,517 Secondary leaching 52,402 53,450 54,519 55,610

CuSO4 plant expenses 134,400 134,400 134,400 134,400 Total Expenditure 2,003,777 2,013,427 2,023,269 2,033,308

Annual balance (nominal) (564,653) (574,302) (584,145) (594,184) Annual balance (discounted) (197,944) (176,602) (157,569) (140,594) Accumulated balance (nominal) (4,401,473) (4,975,775) (5,559,920) (6,154,104) Accumulated balance (discounted) (2,582,753) (2,759,356) (2,916,925) (3,057,519)

6-35 Private: 6,000dmt/month processing/without project Cash Flow【68.2180】(4/4)

Year 12 13 14 15 Unit: Dec. 2001 fix US$ Fix assets investment 100,000 100,000 100,000 100,000

Waste water treatment plant 182,000 182,000 182,000 182,000 Complementary supply materials 504,259 504,259 504,259 504,259

H2SO4: primary leaching 377,280 377,280 377,280 377,280

H2SO4: secondary leaching 47,002 47,002 47,002 47,002 Iron scrap: primary leaching 72,720 72,720 72,720 72,720 Iron scrap: secondary leaching 7,258 7,258 7,258 7,258 Factory supplies & Maintenance 118,111 118,111 118,111 118,111 Ore reception 7,920 7,920 7,920 7,920 Crushing 25,920 25,920 25,920 25,920 Primary leaching 83,520 83,520 83,520 83,520 Secondary leaching 751 751 751 751 Utilities 20,995 20,995 20,995 20,995 Ore reception 4,320 4,320 4,320 4,320 Crushing 288 288 288 288 Primary leaching 12,240 12,240 12,240 12,240 Secondary leaching 4,147 4,147 4,147 4,147 Administration overhead 461,542 461,542 461,542 461,542 Ore reception 93,650 93,650 93,650 93,650 Crushing 25,200 25,200 25,200 25,200 Primary leaching 342,000 342,000 342,000 342,000 Secondary leaching 691 691 691 691 Human resource 522,241 532,686 543,340 554,206 Ore reception 68,037 69,398 70,786 72,202 Crushing 57,295 58,441 59,609 60,802 Primary leaching 340,187 346,991 353,931 361,009 Secondary leaching 56,722 57,856 59,013 60,194

CuSO4 plant expenses 134,400 134,400 134,400 134,400 Total Expenditure 2,043,548 2,053,993 2,064,647 2,075,514

Annual balance (nominal) (604,424) (614,869) (625,522) (636,389) Annual balance (discounted) (125,454) (111,949) (99,902) (89,156) Accumulated balance (nominal) (6,758,527) (7,373,396) (7,998,918) (8,635,307) Accumulated balance (discounted) (3,182,973) (3,294,922) (3,394,824) (3,483,980)

6-36 Private: Improved 6,000dmt/month processing 【Analysis Results】

Financial Indexes

Cu price (US¢ /lb) 68.22 80.00 92.00 102.00

NPV14% (thousand US$) -2,998 -2,913 -2,818 -2,740 IRR #DIV/0! #DIV/0! #DIV/0! #DIV/0! Initial investment (thousand US$) 139 139 139 139 Cash Cost (US¢ /lb) 59.43 59.43 59.43 59.43

Cu Price Sensitivity Analysis Result

-2,600 100% -2,650 68.22 80.00 92.00 102.00 90% -2,700 80% 70% -2,750 60% -2,800 50% -2,850 40% -2,900 30% -2,950 20% -3,000 10% -3,050 0%

NPV14% (thousand US$) IRR

Accumulated DCF per Copper Price

0 -500,000 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 -1,000,000 68.218 -1,500,000 80

US$ -2,000,000 92 -2,500,000 102 -3,000,000 -3,500,000 Year

6-37 Private: Improved 8,000dmt/month processing 【Analysis Results】

Financial Indexes

Cu price (US¢ /lb) 68.22 80.00 92.00 102.00

NPV14% (thousand US$) -3,114 -2,999 -2,868 -2,761 IRR #DIV/0! #DIV/0! #DIV/0! #DIV/0! Initial investment (thousand US$) 499 499 499 499 Cash Cost (US¢ /lb) 52.70 52.70 52.70 52.70

Cu Price Sensitivity Analysis Result

-2,700 100.00% -2,750 68.22 80.00 92.00 102.00 90.00% -2,800 80.00% 70.00% -2,850 60.00% -2,900 50.00% -2,950 40.00% -3,000 30.00% -3,050 20.00% -3,100 10.00% -3,150 0.00%

NPV14% (thousand US$) IRR

Accumulated DCF per Copper Price

0 -500,000 0123456789101112131415 -1,000,000 68.218 -1,500,000 80

US$ -2,000,000 92 -2,500,000 102 -3,000,000 -3,500,000 Year

6-38 Private: Improved 14,000dmt/month processing 【Analysis Results】

Financial Indexes

Cu price (US¢ /lb) 68.22 80.00 92.00 102.00

NPV14% (thousand US$) -3,776 -3,567 -3,331 -3,137 IRR #DIV/0! #DIV/0! #DIV/0! #DIV/0! Initial investment (thousand US$) 2,225 2,225 2,225 2,225 Cash Cost (US¢ /lb) 43.93 43.93 43.93 43.93

Cu Price Sensitivity Analysis Result

-3,000 100.00% -3,100 68.22 80.00 92.00 102.00 90.00% -3,200 80.00% 70.00% -3,300 60.00% -3,400 50.00% -3,500 40.00% -3,600 30.00% -3,700 20.00% -3,800 10.00% -3,900 0.00%

NPV14% (thousand US$) IRR

Accumulated DCF by Copper Price

-2,000,000 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 -2,500,000 68.218 80 -3,000,000 US$ 92 102 -3,500,000

-4,000,000 Year

6-39 Social: Improved 6,000dmt/month processing 【Analysis Results】

Financial Indexes

Cu price (US¢ /lb) 68.22 80.00 92.00 102.00

NPV10% (thousand US$) -776 -672 370 2,671 IRR 53.68% 47.44% #DIV/0! #DIV/0! Initial investment (thousand US$) 600 600 600 600 Cash Cost (US¢ /lb) 54.31 54.31 54.31 54.31

Cu Price Sensitivity Analysis Result

3,000 60.00%

2,500 50.00% 2,000 40.00% 1,500

1,000 30.00%

500 20.00% 0 68.22 80.00 92.00 102.00 10.00% -500

-1,000 0.00%

NPV10% (thousand US$) IRR

Accumulated DCF by Copper Price

3,000,000 2,500,000 2,000,000 68.218 1,500,000 80 1,000,000 US$ 92 500,000 102 0 -500,000 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 -1,000,000 Year

6-40 Social: Improved 8,000dmt/month processing 【Analysis Results】

Financial Indexes

Cu price (US¢ /lb) 68.22 80.00 92.00 102.00

NPV10% (thousand US$) -92 51 1,445 4,516 IRR #DIV/0! 24.92% 153.14% 407.54% Initial investment (thousand US$) 960 960 960 960 Cash Cost (US¢ /lb) 48.13 48.13 48.13 48.13

Cu Price Sensitivity Analysis Result

5,000 450.00% 400.00% 4,000 350.00% 3,000 300.00% 250.00% 2,000 200.00% 1,000 150.00% 100.00% 0 50.00% 68.22 80.00 92.00 102.00 -1,000 0.00%

NPV10% (thousand US$) IRR

Accumulated DCF by Copper Price

5,000,000 4,000,000 3,000,000 68.218 80 2,000,000 US$ 92 1,000,000 102 0 -1,000,000 02468101214 Year

6-41 Social: Improved 14,000dmt/month processing 【Analysis Results】

Financial Indexes

Cu price (US¢ /lb) 68.22 80.00 92.00 102.00

NPV10% (thousand US$) 105 364 2,814 8,197 IRR 11.10% 13.68% 33.88% 72.64% Initial investment (thousand US$) 2,686 2,686 2,686 2,686 Cash Cost (US¢ /lb) 39.92 39.92 39.92 39.92

Cu Price Sensitivity Analysis Result

9,000 80.00% 8,000 70.00% 7,000 60.00% 6,000 50.00% 5,000 40.00% 4,000 30.00% 3,000 2,000 20.00% 1,000 10.00% 0 0.00% 68.22 80.00 92.00 102.00

NPV10% (thousand US$) IRR

Accumulated DCF by Copper Price

10,000,000 8,000,000

6,000,000 68.218 4,000,000 80

US$ 2,000,000 92 0 102 -2,000,000 0123456789101112131415 -4,000,000 Year

6-42

７．Environmentally Friendly Operation Plan at Ovalle Plant ７. Environmentally Friendly Operation Plan at Ovalle Plant In this Chapter, the most desirable operation system at Ovalle discussed in the preceding Chap. 6, is reviewed first in sec. 7.1, and then, more practicable alternative proposed from ENAMI side is discussed in sec. 7.2 as the second best.

7.1 Most Desirable Operation In the previous Chap.6, the economic and financial analyses were carried out in different levels of monthly throughput of crude ores, that is, recent average of 6,000ton, recent maximum 8,000ton and installed capacity of the leaching plant, 14,000ton. In either case, the operation could be feasible if Cu price is over 92, 80 and 68.218¢ /lb respectively. It is necessary to partly modify the present model plant for monthly 6,000ton, to partly reinforce for 8,000ton and to newly install a separate “full scale plant” for 14,000ton respectively for the treatment of total volume of the waste solution from the leaching section. In each case, 40ton of copper sulfate are produced as a new product prior to the Cu precipitation step and this also contributes to reduction of the solution volume. Among the three cases discussed, monthly throughput of 14,000ton is the most desirable from economical and environmental standpoints. The flow diagram of this “full scale operation” is shown in Figure 7.1.

Oxide copper ore (*1) through crushing and agglomeration

Leaching (*2)

Pregnant solution

Precipitation Solvent-Extraction

Stripping and Crystallization

Copper precipitate Waste solution Copper sulfate (*4) : Cement copper Treatment of waste solution (*3)

Treated solution

Figure 7-1 The Best Operation Flow Thoughtful to Environment for Oxide Copper Ore *1：14,000t/month（Full capacity operation） *2：Leaching composition: primary leaching 52%＋secondary leaching 48% *3：Full-scale plant with capacity of 600m3/day may be constructed to treat all waste solution. *4：Production: 40t/month

7- 1 As for sulfide Cu ores, the present operation with monthly throughput of 11,000ton (increased from 7,000ton in 2002) shall be continued. Discussions should be made further before conclusion, considering the movement of Cu price, situation of crude ore supply, installation and operation costs of the full scale plant and others.

7.2 More Practicable Operation In this section, more practicable and pollution free operation is studied including ENAMI’s opinion to avoid heavy investment.

7.2.1 Operation Policies by ENAMI (as of March, 2002) Newly established policies on Ovalle operation are described below. (1) Processing of oxide ores ① No pollution shall be caused again. → No waste solution shall be discharged from the plant : All solution (treated or untreated) shall be returned to the leaching step for reuse. ② Under the current economic situation in debt, it is impossible for ENAMI to make such heavy investment on the solution treatment newly. The plan shall be abandoned. ③ The existing model plant shall be operated fully, though operation cost is severe. → The rated capacity is 100m3/day but could handle more. ④ According to the recent results of oxide ore supply, the maximum level is 8,000ton/month (solution volume : 330m3/day) and averaged 6,000ton/month (250m3/day). ⑤ Discussion shall be made to reduce the waste solution volume. → One is production of

copper sulfate (CuSO4・5H2O) and another is introduction of solvent extraction and electro-winning (SX-EW). The latter is not employed at the moment. ⑥ Discussion shall be made to recover Cu remained in the waste solution. → All solution (treated or untreated) shall be returned to the leaching step.

⑦ Trial for unique product → Production of CuSO4・5H2O from the pregnant solution (before Cu precipitation). According to an additional policy issued by ENAMI in Oct.,2002, treatment of the oxide crude Cu ores shall be adjusted to the possible maximum capacity of the model plant and any byproduct shall be studied from the model plant to compensate the operation cost, which currently lies between US$ 13,000～15,000/month. (2) Processing of sulfide ores : Present operation shall be continued.

7.2.2 Discussion on the Processing Methods In this section, possible processing methods are studied. The results are summarized in Table 7.1. (1) Oxide ores 1) Cu precipitation process (so-called cementation process) Leaching→Precipitation→Cu-Precipitate : Accompanied with contaminated solution.

7- 2 ① In case that the waste solution is treated a) No by-product produced ⅰ. Treated solution is discharged into river. : in the Table 7-1, ①→②→③→⑧ ⅱ. Treated solution is returned to the leaching step. : ditto ①→②→③→⑨ : This contributes to Cu recovery up but attention should be paid in balance of solution volume on a long term basis.

b) Byproduct 1 is produced : ①→②→④→⑨ ：Hematite (Fe2 O 3), Ferrite (FeO･Fe2O3) and others, Test program carried out by Metal Mining Agency of Japan is illustrated in Figure 7-2. According to the results, its feasibility is questionable. 3+ c) Other case 1 : Byproduct from Fe , ferric sulfate (Fe2(SO4)3) etc.: ①→②→⑤→⑧ or ⑨ d) Other case 2 : Treated (oxidized, Fe2+→Fe3+) solution is returned to the leaching step : in the Table ①→②→⑥→⑨ : for leaching of sulfide Cu minerals. e) Other case 3 : Iron oxidizing bacteria are intentionally added into the leaching step (aeration needed) → to promote Cu leaching of sulfide ores f) Other case 4 : Iron oxidizing bacteria are added into evaporation ponds (no bottom lined) along with alkali agents (aeration needed) → anti-pollution effect by clogging

the pond surface with Fe(OH)3. g) Other case 5 : Accumulated solution in the pond shall be treated at the model plant → prevention of pollution ② In case that the waste solution not treated a) Waste solution is directly returned to the leaching use : in the Table①→②→⑦→⑨ → contributes to Cu recovery up, however, accumulation of heavy metals and imbalance of solution volume may be brought. b) Waste solution is accumulated in the evaporation pond (case 1) : directly discharged into the pond, of which bank and bottom are not protected against penetration. In the Table ①→②→⑦→⑩. → Even if large volume of water is evaporated, ferrous ion and others inevitably penetrate into the soil resulting in pollution of the river Ingenio. This case is never accepted. c) Waste solution is accumulated in the evaporation pond (case 2) : directly discharged into the pond, of which bank and bottom are lined with waterproof materials (high density polyethylene etc.). : ①→②→⑦→⑪ → If evaporation is above discharging volume, no penetration nor contamination occurs. But ferrous ions etc. are deposited to accumulation*1 Finally, restoration and plantation are needed. *1 : ferrous sulfate FeSO4 etc.

2) Production of copper sulfate (CuSO4・5H2O) : leaching → solvent-extraction →

electro-winning → reverse extraction and crystallization → CuSO4・5H2O : in the Table ①→⑫→⑬ : As the solvent is circulated for reuse, volume of the waste solution is considerably reduced. 3) Solvent-extraction and electro-winning from the pregnant solution : leaching →

7- 3 solvent-extraction and electro-winning (SX-EW)→ cathode Cu : ①→⑭→⑮ : As the solvent is circulated for reuse, volume of the waste solution is considerably reduced. 4) Sale of the pregnant solution : The pregnant solution is sold to any nearby mine, which operates SX-EW process. No waste solution from Ovalle plant but feasibility study is needed for realization. (2) Sulfide ore processing 1) Flotation : flotation → Cu concentrate At present, flotation tailings are piled into the tailing dam, of which overflow water is circulated for reuse. No pollution is found.

7.2.3 Case Study Possible flows are shown independently as below. Circled number shows the corresponding operation in the Table 7.1. (1) Oxide Cu ore processing Here, P : Volume of waste solution to be treated (m3/day) Q : Max. volume to be treated at the model plant (m3/day) Q

plant (effluent is discharged into the river or returned to the leaching step) [x1] + ⑦

untreated (circulation, FeSO4 etc,) [x2] : x1 + x2 = P, x1 < Q 2) Case 2 : {① leaching →② precipitation (Cu precipitate) →③ treatment at the model

plant (effluent discharged or returned) [x3] (+⑦ untreated (circulation, FeSO4 etc.) [x4]) ＋ (① leaching → ⑫ solvent-extraction → ⑬ reverse extraction・crystallization

(CuSO4) [x5]) : x3 +x4+ x 5 = P, x3 < Q 3) Case 3 : ① leaching → ② precipitation (Cu precipitate) → ④ separate treatment 1

(hematite, ferrite) [x6] : x6 = P 4) Case 4 : ① leaching → ② precipitation (Cu precipitate) → ⑤ separate treatment 2

(ferric sulfate) [x7] : x7 = P 5) Case 5 : ① leaching → ② precipitation (Cu precipitate) → ⑥ oxidizing treatment

alone (ferrous → ferric) [x8] : x8 = P

6) Case 6 : ① leaching → ② precipitation (Cu precipitate) → ⑦ no treatment [x9] :

x9 = P 7) Case 7 : ① leaching → ⑫ solvent extraction → ⑬ reverse extraction ・

crystallization (CuSO4) [x10] : x10 = P 8) Case 8 : ① leaching → ⑭ solvent extraction → ⑮ elctro-winning (electrolytic Cu)

[x11] : x11 = P

9) Case 9 : ① leaching → ⑯ sale (pregnant solution) [x12] : x12 = P

(2) Sulfide Cu ore processing 1) Case 1 : ⑰ flotation

7- 4 7.2.4 Operation in Accordance with Current Ovalle Situation Operation policies in accordance with the present situation are discussed below, combining the above discussion and ENAMI’s policy. (1) Oxide Cu ore processing 1) Prerequisite conditions ① Average throughput (actual level) : 6,000ton/month[72,000ton/year] (capacity utilization rate 43%) {Maximum throughput (actual level) : 8,000ton/month[96,000ton/year] (capacity utilization 57%)} ② Volume of waste solution : 250m3/day (actual average) is to be treated. ③ Maximum volume of treatment at the model plant : 176m3/day 2) Order of priority Discussion is proceeded following the above Case 2) of Case study in section 7.2.3 and in order of operational priority. ① leaching → precipitation (with iron scrap) : volume of solution treatment : A m3/day The maximum treatment is supposed to go up to 176m3/day at the model plant due to decrease in ferrous ion concentration. Thus, A = 176m3/day is taken as the maximum. Treated solution is returned to the leaching step. Neutralization sediments after the treatment could contain a small quantity of harmful metals like arsenic. It is desirable to accumulate these materials in evaporation ponds(*2), protected from penetration, for final disposal. *2 : correspond to control type final disposal site in Japan

② leaching → solvent extraction → CuSO4・5H2O production : volume of solution reduced through this process : B m3/day

When 40ton/month of CuSO4・5H2O is produced, reduction of the volume would be 30m3/day. Then, 30

Table 7-2 summarizes the more practicable operation flows under the current situation.

7- 5

Table 7-2 Operation Flow Suitable for Present Conditions ：［Oxide copper ore quantity 6,000t/month, soluble copper grade 2.48%(supposition), copper quantity 128t/month］

（Crude ore） Crushing Agglomeration Leaching （Pregnant solution）

Precipitation （Copper precipitate）135t/month, 83.00 Cu-%, 112 Cu-t/month ～ 117t/month, 83.00 Cu-%, 97 Cu-t/month］ (Waste solution) Treatment Recycle to leaching section [176m3/day] Non treatment Recycle to leaching section ［30～0 m3/day］ Solvent-Extraction(SX-EW) Stripping and Crystallization （Copper sulfate）［40～99t/month, Cu 10～25t/month］

3) Financial analysis : This case, in which 6,000ton/month of crude ore is processed,

producing 40～99ton/month of CuSO4・5H2O, can not be feasible. (2) Sulfide ore processing Current operation shall be continued. Target of the operation : 6,300ton/month (75,600ton/year) [capacity utilization : 90%].

7.3 Environmentally- Friendly Operation Program Transition from the former operation flow (causing pollution) to the current one (no pollution) is illustrated in the Figure 7-3.

7- 6 Table 7-1 List of Treatment Process: Ovalle Plant, ENAMI

1) Treatment of oxide copper ore

① Leaching 〈Pregnant solution〉 ② Precipitation 〈Copper precipitate (Cement copper)〉〈Waste solution〉 ③ Treatment in model plant 〈Neutralized sediment〉〈Treated solution〉 ⑧ Discharge to river ⑨ Recycle to leaching section

④ Other treatment 1 〈By-product 1：Hematite Fe2O3、Ferrite FeO･Fe2O3〉〈Treated solution〉 ⑧ Discharge to river ⑨ Recycle to leaching section

⑤ Other treatment 2 〈By-product 2：Ferric sulfate Fe2(SO4)3〉〈Treated solution〉 ⑧ Discharge to river ⑨ Recycle to leaching section

7 3+

- ⑥ Only oxidizing 〈Ferric Fe 〉 ⑨ Recycle to leaching section 7 ⑦ No treated ⑨ Recycle to leaching section ⑩ Evaporation pond without sealing work ⑪ Evaporation pond with sealing work 〈By-product 3：

Ferrous sulfate FeSO4〉

⑫ Solvent-extraction (SX) ⑬ Stripping and crystallization 〈Copper sulfate CuSO4･5H2O〉 ⑭ Solvent-extraction (SX) ⑮ Electro-winning (EW) 〈Electrolytic copper (Cathode copper)〉 ⑯ Sale 2) Treatment of sulfide copper ore ⑰ Flotation 〈Copper concentrate〉〈Tailing（Waste）〉 ⑱ Tailing pond 〈Clarified water〉 ⑲ Recycle to grinding and flotation section 〈Sediment〉

Mine drainage with Fe2+

Neutralization with removal of As

Solid/liquid separation

Sludge Filtrate

Bacteria Oxidization Fe2+→Fe3+ Neutralization

CaCO3 Neutralization Solid/liquid separation

Solid/liquid separation Sludge Clarified water Sludge Clarified water

：Fe(OH)3

Washing Mixture

Drying Aging

Calcination Calcination Magnetic separation

Magnetics Non magnetics

Rough Hematite Hematite Ferrite Gypsum Discharge

(*1) ：Fe2O3 ：FeO･Fe2O3 ：CaSO4 to river (*2) (*3)

Figure 7-2 Development of Technology to Recover Metals from Mine Drainage: Test Flow *1：In case that As is contained, the product has to be disposed. *2：Colorant (colcothar, etc.), abrasive, raw material for ferrite, etc. *3：Electric-wave adsorbent, magnetic material, magnetic fluid, formulation material, etc.

7- 8 〈 Previous operation conformation without consideration for environment : Occurrence of industry pollution 〉 Oxide copper ore Sulfide copper ore

Crushing Crushing

Agglomeration Grinding

Leaching Flotation

Precipitation Copper Tailing concentrate Copper precipitate Waste solution Tailing pond : Cement copper Evaporation pond Clarified water Underground infiltration and effluence 〈 Industry pollution 〉Pollution of underground/river water

〈 Future operation conformation with consideration for environment after Sep. 2001 : Prevention of industry pollution 〉 Oxide copper ore Sulfide copper ore

Crushing ［Following processes are to be same as in previous operation] Agglomeration

Leaching

Precipitation [Main-system] Solvent-Extraction (SX) [Sub-system]

Copper precipitate Waste solution Stripping and Crystallization : Cement copper Waste solution treatment Copper sulfate

(All recycle) Treated solution （No treated waste solution）

Figure 7-3 Study on the Operation Conformation Flow with Consideration for Environment

7- 9

８．Possible Application of Bio-Technology in Chile (M/P) ８．Possible Application of Bio-Technology in Chile (M/P) In this Chapter, discussions are made on whether application of this type of bio-technology is widely accepted in other industrial sites in Chile.

8.1 Outline of Bio-Technology in This Report Bio-technology employed in this Report is utilization of iron oxidizing bacteria, “Thiobacillus ferrooxidans”, which are capable of oxidizing(*1) ferrous ions into ferric under acidic circumstance. Thus, these bacteria are independent self-nourishing ones, fixing carbon dioxide to grow with use of energy obtained through oxidation. 2+ 3+ - *1：2FeSO4+1/2O2+H2SO4 → Fe2(SO4)3+H2O (Fe → Fe +e ) Application of this bio-reaction to oxidation is superior to that of usual chemical one in achieving environmentally-friendly operation as well as in reducing costs.

8.2 Prerequisites for Application of Technology For application of this technology, it is indispensable for the bacteria to be able to grow. First, necessary conditions are listed below. ① Sulfate acidic solution : in case of mixed acid, content of sulfate ion should be dominant. As halogen ions have negative influence on bacteria growth, these inhibitors should be under certain concentration listed below. ② pH range should be 1.3～4.5 (most suitable pH : 2.5). ③ Temperature should be 10～37℃ (most suitable : 30～35℃) : activities under 10℃ are reported, though. ④ Aerobic atmosphere 2+ ⑤ Inorganic substrata are coexistent : ferrous (Fe ) , sulfur (S), thiosulfuric acid (H2S2O3) etc. ⑥ Inhibitors should be under certain concentration.

Highly sensitive and low Comparatively high durability Medium durability durability －－(*2) Hg, Ag, Mo, Te, Se, U, Sn, As, NO3 , Cl Zn, Ni, Co, Cu, Mn, Al, Cd, CN－, F－ Low molecular organism Cr Specific organism Note) Durability of bacteria might be improved when cultured as inhibitor concentration is increased gradually. *2 : limit is normally under 1g/L, however, could be improved up to about 10g/L if cultured gradually.

8.3 Possibility of Application This type of bio-technology could be applied to the following four industrial fields [(1)～(4)] inside Chile.

8- 1 (1) Treatment of drainage from operating or closed mines processing. If waste solution is accumulated in evaporation ponds, harmful elements in the solution penetrate into soil from their bottom or sides, unless kept waterproof, resulting in contamination of nearby water system. Just like in Ovalle, if ferrous ions are in solute, they can be oxidized, neutralized and removed as sediments to prevent pollution. This type of application is not seen in Japan since all the Cu mining are now closed. (2) Treatment of drainage from operating or closed mines As mine drainage usually contains harmful elements, nearby water systems are often contaminated. If ferrous ions are in solute together with As3+, 5+ or Cd2+, they can be oxidized, neutralized and removed with use of bacteria activity. This procedure has been realized in Japan at former Yanahara and Matsuo mine etc. successfully. The process flow is illustrated in Figure 8-1. In the Figure, key application point is indicated as Iron oxidizing with bacteria.

Polluted mine drainage pH about 1～3

Iron oxidizing with bacteria Fe2+→Fe3+(, As3+→As5+)

Alkali: CaCO3, Ca(OH)2, etc. 3+ Neutralization pH about 3.5～4: Fe →Fe(OH)3 with coprecipitation(As5+, etc.) Solid/liquid separation

Neutralized sediment (sludge) Clarified water

Fe(OH)3 with As, etc. pH regulation Waste dam, etc. as final disposal Discharge to river

Figure 8-1 An Application of Bio-technology to Treatment of Mine Drainage

(3) Treatment of flue dusts at smelters Through smelting operation some flue dusts, which contain large quantity of valuable and harmful metals are often stock piled as intermediate refractory material. If the heavy metals dissolve, nearby soil and water are inevitably contaminated. This problem can be handled with use of this technology not only for elimination of contamination but for recovery of valuable metals like Cu. In Japan, this process is now realized at Kosaka Cu smelter. One example of treatment flow at Cu smelter is illustrated in Figure 8-2. In the Figure, key application point is indicated as [Iron oxidizing with bacteria].

8- 2

Waste water residue Flue dust Lead concentrate

H2SO4 Leaching

PbSO4 Leaching electric furnace st H2S 1 Copper removal CuS Flash smelting furnace

CaCO3 Neutralization

CaSO4 Selling Iron precipitate(☆) Arsenic removal

FeAsO4 Waste storage dam nd H2S 2 Copper removal CuS Flash smelting furnace Flotation waste water Air Iron oxidizing with bacteria

CaCO3 Iron removal Iron precipitate(☆) Waste storage dam

NH4OH and Slaked lime Zinc and Cadmium

Zn(OH)2 Zinc refinery Waste water

Figure 8-2 An Application of Bio-technology to Cu Smelting Operation (Flue Dust)

(4) Leaching of secondary Cu sulfide ores with use of bacteria Acid leaching has been limited to oxide Cu processing only until recently, however, with use of bacteria secondary Cu minerals like chalcocite and covellite became target of this process. Traditionally from these secondary Cu ores, Cu concentrate is obtained by flotation first, and then electrolytic Cu is finally produced through pyrometallurgical process. This is still a leading process widely employed. But recently, so-called bacteria leaching method is positively introduced not only for low grade ore or waste rocks, which are economically infeasible with traditional process, but also for average ores, which can be processed by normal flotation and smelting process. After leaching, electrolytic Cu is finally produced through solvent-extraction and electro-winning (SX-EW) method. This series of processing is now employed at almost all mines and is being studied at some mines for future operation because entire operation costs could be much decreased compared to the traditional operation. This unique method will be spread further especially for secondary Cu ores. Leaching with bacteria is theoretically considered in two ways as follows.

8- 3 ① Indirect leaching mechanism : Ferrous ions are oxidized with bacteria activity to ferric, which chemically react with sulfide minerals to oxidize. (In case of covellite) 2+ + 3+ 4Fe +4H + O2 = 4Fe + 2H2O (1) CuS + 2Fe3+ = Cu2+ + 2Fe2+ +S0 (2) Usually, the reaction (1) proceeds so slowly under acidic condition but with the presence of bacteria its velocity could reach five hundred thousand times as fast as the usual. Ferric (Fe3+) ion acts as an oxidizing agent on CuS, which is oxidized and dissolved to form Cu2+, while ferric ion is reduced to ferrous (Fe2+) and prompts the reaction (1). In this mechanism ferrous ions are indispensable and naturally available by oxidation

of sulfide minerals containing Fe, typically iron pyrite (Fe2S) following the reaction (3) shown below.

2FeS2＋7O2＋2H2O＝2FeSO4＋2H2SO4 (3) ② Direct leaching mechanism : The bacteria themselves adhere to the surface of sulfide acting as a catalyst to prompt oxidizing reaction as below. + 2+ CuS＋2O2＋2H ＝Cu ＋H2SO4 (4) Yet some factors of the reaction are not found out. This process of bacteria leaching are already practiced in heap/dump leaching for Cu ores, in place leaching for uranium ores and others. At present bacteria that naturally grow at site are being utilized in most cases. But if any treatment facilities of waste solution containing ferrous ions are available at hand, cultured bacteria could be intentionally employed for leaching of Cu minerals. Typical examples were seen at Kosaka and Tsuchihata mine, now closed, in Japan. Types of bacteria useful for leaching process are Thiobacillus ferrooxidans and Thiobacillus thiooxidans, Leptospirillum ferrooxidans, Acidiunus brieleyi, Metalloshaera sedula, Sulfolobus acidocaldarius, TH1, TH2, TH3, ALV, BC, Sulfobacillus thermosulfidooxidans, Sulfobacillus thermosulfidooxidans subsp. thermotolerans, Sulfobacillus thermosulfidooxidans subsp. asporogenes, Thiobacillus prosperus, Thiobacillus cuprinus, Thiobacillus acidophilus. Primary Cu mineral, chalcopyrite, is hardly leached by acid even with help of bacteria due to slow reaction. Leaching methods for this mineral is now being studied with ammonia, halogens, strong oxidizing agents or pressure leaching etc. (5) Others 1 : Purification of circulated acid to leaching step Solvent Extraction and Electro-Winning process is now widely applied to oxide Cu at many mines. A little concern remains in the process that Fe accumulates in circulated acid resulting in decrease of Cu recovery by lowering selectivity of solvent in extracting step as well as in decrease of electrolysis efficiency. It is expected to eliminate accumulated Fe with use of this technology for improvement of operation results. But as further studies are needed, discussion shall be excluded at the moment. No examples are seen in Japan.

8- 4 Others 2 : Recovery of Au and Ag contained in pyrite or arsenopyrite (FeAsS) Au and Ag in sulfide minerals are hardly recovered even by leaching with cyanides. But it is possible to increase their recovery rate by pre-treatment with bacteria. Several methods like Biox, BioPro, GeoCoat process are proposed. At the moment these shall be excluded out of discussion.

8.4 Discussion on Possible Application Sites in Chile Concrete studies are made on possible application of this bio-technology in each industrial field discussed in the previous section, 8.3. (1) Treatment of waste solution from Cu precipitation method in oxide Cu processing Discussion is made on ENAMI’s processing plants first as well as some small and medium size plants other than ENAMI. As the results, the technology could be possibly applied to the following sites. ① Ovalle plant, ENAMI : The rest of the waste solution beyond capacity of the model plant could be a target. ② Vallenar plant, ENAMI : (solution pH : 2.7, Fe2+9,700mg/L, T-Fe 16,800mg/L, Cu 467mg/L, Cd 0.43mg/L, Pb 1.1mg/L, As 1.9mg/L) ③ Cu recovery plant from precipitation step of Cu smelter dusts (for example : Monte Carmelo plant, where flue dusts from Cu smelter is treated by exchanging precipitation method (solution pH : 2.4, Fe2+ 35,400mg/L, T-Fe 36,800mg/l, Cu 906mg/L, Cd 1,410mg/L, Pb 0.7mg/L, As 3,200mg/L) ④ Cu recovery plants from leaching-precipitation step at small scale mines : The following private mines could introduce the method, though their scale are too small. Name pH Fe2+ T-Fe Cu Cd Pb As (mg/L) C.G. plant 0.4 49,000 54,100 239 0.14 1.1 1.8 L.C plant 3.4 unknown 3,140 173 0.09 0.6 0.16 S.G plant 3.8 unknown 51,100 274 0.19 1.2 0.71

In case of above ③ and ④, it is recommended that ENAMI takes a leading position of installation of a centralized treatment plant, now that the technology was transferred through this Study. Inside ENAMI, M.A. Matta plant is processing only sulfide Cu and out of consideration to apply from the beginning. El Salado plant is processing oxide Cu, however, can not

introduce this method while treating Atacamite (Cu2Cl(OH)3) due to extraordinarily high content of chlorine (39.8g/L) in the solution, far beyond the upper limit (10g/L) for bacteria activity. Nor at Taltal plant, where sea water is utilized in the process that brings chlorine concentration far above the limit. Inside CODELCO no Cu precipitation method is being employed. Among the private miners, many mines like Dona Ada, El Indio, Fortuna de Cobre, La Cascada, Lo Aguirre etc. have gradually switched Cu precipitation method to modern SX-EW

8- 5 from the beginning of 1990’s. Currently, there are no medium or large scale mines operating this precipitation except very small ones. (2) Treatment of mine (operating or closed) drainage On this item following discussions were carried out. Prerequisite to target mine : located in an area south from Copiapo city in the Ⅲ region, at least occasionally rains, sulfide mineral deposit especially containing iron pyrite(*3), open pit or underground, mine drainage is discharged into nearby river with no treatment. C.A. mine is an example : PH Fe2+ T-Fe Cu Cd Pb As (mg/L) Example ① 1.1 60 60 247 0.06 0.1 0.06 Example ② 3.9 190 190 548 0.13 0.2 0.24 *3 Sulfur contained in sulfide minerals is easily oxidized to form sulfuric acid solution. Especially iron pyrite is very likely under existence of oxygen, water and bacteria as in the reaction of (3), described in section 8.3 (4). Also from sulfur produced by the reaction (2) in the same section, is easily dissolved to form sulfuric acid as below, especially with help of bacteria. 0 2S ＋2H2O＋3O2＝2H2SO4 (5) This sulfuric acid dissolves harmful heavy metals, which contaminate nearby water systems. (3) Treatment of flue dust at smelters Application of bio-technology was studied as follows. ① ENAMI : Ventanas Cu smelter ② CODELCO : Chuquicamata, Caletones (El Teniente), Potrerillos (El Salvador) smelters ③ Private companies : N.A. Cu smelter, D.C. Cu smelter When Fe content in flue dust is insufficient, addition of Fe3+ would be indispensable. This is the case ①, above mentioned. In the case of ② and ③, more study is needed. In the case of Paipote Cu smelter of ENAMI, flue dusts are not discharged out of the operation and then excluded from the discussion. (4) Bacteria leaching for secondary Cu minerals Application was studied as follows.

① Bacteria leaching could be applied to any mines of secondary Cu like chalcocite (Cu2S) or Covellite (CuS), if leaching and SX-EW process will be programmed for production of electrolytic Cu, not through flotation method (for example, E, Z, and Q.B. mine etc.)

The present situation of Cu production by Chilean large mines is shown in Table 8-2.

8.5 Summary of Possible Application of Bio-Technology in Chile Supposedly in Chile, “Treatment of mine (operating or closed) drainage” described in 8.4 (2), will be given the first priority of technical discussion. But actually, the situation of water contamination is not clear, though it is supposed to happen in wide area.

8- 6 Accordingly, along with the field survey of current contamination, application of this technology should be studied in detail on individual site. Some detailed items are listed in the Table 8-1, in which the underlined parts are especially to be noticed. Finally it is concluded that in Central and South America, application of the technology is possible.

8- 7

Table 8-1 Treatment of Mine Drainage from Operating or Abandoned Mines with Bio-technology (Scheme) (1) Environmental survey 1) Present situation survey ① Survey of pollution source: Grasping quantity and quality of drainage from mines, and quantity and quality of water and bottom sediment of relative rivers by preliminary survey to confirm their concentration and quantity of load. Then, defining pollution source. At the same time, grasping pH, acid with sulfuric acid, concentration of Fe2+, with or without iron oxidizing bacteria and concentration of inhibitors to the bacteria to confirm chance to apply to the treatment of mine drainage by using bio-technology with iron oxidizing bacteria. ② Survey of pollution situation: Mapping of pollution situation to define pollution degree in contrast to the standard. Then, drawing contour line on pollution to confirm degree and range of pollution. Moreover, Grasping order of priority of measures necessary to every pollution source according to largeness of pollution impact. ③ Survey of pollution mechanism: Clarifying pollution route and reaction from pollution source ④ Survey of suffering situation: Grasping suffering situation of human body of every industry 2) Monitoring ① Formulation of monitoring plan: Fixing monitoring items and points necessary for future continued monitoring according to result of above-mentioned present situation survey. ② Monitoring survey: Sampling and analyzing on water quality, and measuring quantity of water at regular intervals to accumulate data. Revising pollution source, pollution situation and pollution mechanism with the result, and grasping change with the passage of time. ③ Formulation of water quality analysis model: Constructing model to analyze quality of water concerning pollution mechanism. ④ Survey of water quality simulation: Grasping degree of mitigation for pollution at every polluted point according to method and degree of measures for mine pollution prevention at pollution sources with simulation by above-mentioned model of water quality analysis. (2) Study on measures for mine drainage 1) Study on technology of measures for mine pollution: Grasping overall technology of the measures for mine pollution, that is, pollution source measures, mine drainage treatment, etc.. 2) Study on technology of measures for mine drainage: Narrowing down technology of measures for polluted mine drainage necessary to site where mine pollution occurs in Chile, from above-mentioned technologies. 3) Formulation of measures process: Studying process of measures of mine pollution prevention for every pollution source. ⇒ Herein, the bio-technology mentioned in this report may be applicable. Construction of process with bio-technology by using iron oxidizing bacteria: Peculiar technique has to be necessary. 4) Test of measures process: Confirming the process and grasping optimum treatment condition. 5) Design of facilities: First, conducting conceptional design for pollution source with larger impact, and conducting analysis economics and financial affaires. Succeedingly, conducting detail design. (3) Practice of measures for mine drainage 1) Construction of model plant (pilot plant): Small-scale model plant will be constructed based on above-mentioned design to restudy optimum condition and confirm fulfillment of criteria for applied technology. 2) Construction of full-scale plant 3) Operation of the plant: Conducting mine pollution prevention.

8- 8 Table 8-2 Major Copper Mine in Chile Processing Ore*5 Location Production in 2000 No. Name of Mine Ownership Sulfide Oxide : Region Cu ×103t/year 1 Escondida BHP 57.5+RTZ 30+JECO 10 *1+IFC 2.5% ○ ○ Ⅱ 917 2 Chuquicamata CODELCO ○ ○ Ⅱ 630 Falconbridge 44+AAC(Anglo American plc.) 3 Collahuasi ○ ○ Ⅰ 436 44+Japan Conso. 12%*2 4 El Teniente CODELCO ○ ○*6 Ⅵ 356 Antofagasuta Minerales plc. (Luksik) 50.55 5 Los Pelambres ○ Ⅳ 310 +Anaconda Chile 9.45 +Japan Conso. 40%*3 6 Andina CODELCO ○ Ⅴ 258 7 Candelaria Phelps Dodge 80+Sumitomo group 20%*4 ○ Ⅲ 204 8 Radomiro Tomic CODELCO ○ Ⅱ 191 9 El Abra Phelps Dodge 51+CODELCO 49% ○ Ⅱ 191 10 Los Bronces Exxon Mobil (Disputada de Las Condes) ○ ○ M*7 170 11 Zaldivar Placer Dome ○ ○ Ⅱ 148 12 Cerro Colorado Billiton (Rio Algom) ○ Ⅰ 115 13 Mantos Blancos AAC ○ ○ Ⅱ 102 14 Salvador CODELCO ○ ○ Ⅲ 81 15 Quebrada Blanca Aur 76.5+Pudahuel 13.5+ENAMI 10% ○ ○ Ⅰ 73 16 El Soldado Exxon Mobil (Disputada de Las Condes) ○ ○ Ⅴ 68 17 Manto Verde AAC ○ Ⅲ 54 18 Michilla (Lince) Antofagasta (Luksik) ○ ○ Ⅱ 53 19 Lomas Bayas Bolden: Noranda+Falconbridge ○ Ⅱ 51 20 Andacollo Aur 63+Pacifico 27+ENAMI 10% ○ Ⅳ 21 21 El Indio Barrick ○ Ⅳ 14 22 Ivan Zar Milpo (Peru) ○ Ⅱ 13 23 Minera Valle Central Valle Central ○ Ⅵ 12 24 Punta del Cobre Punta del Cobre ○ Ⅲ 10 25 Las Luces Las Luces ○ Ⅱ 10 26 La Cascada Pudahuel ○ Ⅰ 5 27 Lo Aguirre Pudahuel ○ M*7 5 Note *1: Mitsubisi-shoji 6+Mitubishi-material 2+Nikko-kinzoku 2% *2: Mitsui-bussan 6.9+Nikko-kinzoku 3.6+Mitsui-kinzoku 1.5% *3: Nikko-kinzoku 15+Mitsubishi-material 10+Marubeni 8.75+Mitubishi-shoji 5+Mitsui- bussan 1.25% *4: Sumitomo-kinzokukouzan 15+Sumitomo-shoji 5% *5: Sulfide copper ore (process: flotation, product: copper concentrate), Oxide copper ore (process: SX-EW, product: electrolytic copper[cathode copper]) *6: This SX-EW is brought about by treatment of acid drainage water from mine. *7: Metropolitan

8- 9

９．Conclusion ９．Conclusion

The Study project that has searched any economical and environmental improvements in the operation of Ovalle plant, ENAMI, for thirty nine months since Oct., 1999, was now brought to a conclusion. Throughout the Study period, surrounding economic conditions have been unstable and social crises like deflation, monetary crisis and unrest of employment were seriously likely to happen worldwide. Also in the copper producing industry, mining activity that was ever seen in the past, for example, the first half of 1990‘ s has never encountered throughout the period due to the depressed price of this metal at the market. In the Republic of Chile, holding the first place in the industry, small and medium miners have suffered the lower price and were forced to reduce their production, while the large mining companies are still operating favorably. The technical counterpart of the project, ENAMI, promoting small and medium size miners on the one side, are now also suffers a shortage of ores on the other, because it entirely depends upon outside suppliers for crude materials. Although there might be different opinions from the social standpoint of ENAMI, it is desirable for ENAMI to program an independent operation, for example, by operating its own mines or by cooperating with a third party for full supply of crude ores. Should improvement of productivity be reflected in the profit, management would be much encouraged itself. Increase in production could contribute most to profit increase, however, in case of Ovalle profit will be raised by accumulation of minor technical works. For that purpose, accumulation of basic data and experimental results is indispensable. Installation of the Model Plant was completed successfully in good cooperation with the counterpart throughout basic tests, plant design, installation works and demonstration test operation. Waste solution from the previous leaching section was purified through treatment at the model plant as expected. Also actual treatment capacity of the plant exceeded 100m3 per day, originally designed. Including technology transfer the project has proved very successful in the technical aspects. Design of a so-called “full scale plant”, in which the model plant shall be replaced by an industrial one to meet full volume of the waste solution from the leaching step, was conducted based upon the maximum treatment capacity at the leaching operation with 14,000ton of crude ore per month. Total volume of the waste solution will reach 600m3 a day. If this plant is realized, the existing model plant shall be operated as a supplement and the investment for the new installation would cost approximately US$ 2.12 million. Based upon this full scale operation and full volume of waste solution treatment, economic analyses were carried out as case study on different levels of the market price of copper. However, usual Cash Flow analysis, detailed in the Chap. 6, indicated that no feasible results would be brought in each case. This is a weak point in putting some environmental countermeasures in practice, because no profits are unlikely to be brought in many cases.

9-1 For justification of environmental projects like Ovalle, it is important to consider any impacts, which could influence on nearby communities. In this Project, possible economic effects on the neighboring farmlands, meadows, mines etc. were quantitatively analyzed. They are : ① The value of land, which has remarkably decreased due to contamination, shall be re-established through restoration works. ② Economic effects on the ore supplying miners shall be included, when Ovalle plant is fully operated. ③ Saving in water consumption inside entire community shall be economically analyzed. As the results of these analyses, it was found that the full scale (14,000t/month) operation could be feasible if the copper price is above US¢ 68/lb-Cu, when the above factors are included. Now that the full scale operation at Ovalle could be feasible, the installation of full volume solution treatment plant is highly recommended. Once this is fulfilled, no contamination shall be discharged out of the plant, copper recovery will be improved by circulating the waste solution for reuse and ideal operation would be established at Ovalle both economically and environmentally. However, current situation surrounding the copper mining industry is too severe to allow ENAMI a large amount investment at once. It would be appropriate to leave the final judgement to ENAMI management on how and when the investment should be realized. For the time being, actual operation will last at around 6,000 ton per month but if the situation turned favorable, full scale operation (14,000ton/month) as well as installation of full solution treatment plant should be promoted. While the current low level operation continues, another discussions are needed on how environmental requirements shall be met with use of the existing model plant alone. On this point, the results of discussion made between the both parties are reported in the Chap. 7. of this Report. Environmental countermeasure realized at Ovalle was further discussed through data collection and field survey to apply to other copper processing plants in Chile. But unfortunately suitable plant is not found yet because the operation of copper precipitation after leaching is declining these days replaced by unique process, SX-EW. Accordingly, application of this bio-technology was studied widely on entire mining industry and summarized in the Chap. 8 of this report, which has not yet completed, though. It is expected ENAMI or any institute would promote the ideas to make further progress in future. Although consciousness against pollution is gradually raised recently, it is not satisfactorily enough. At Ovalle plant, pollution shall be prevented from now on, needless to say, also water and soil contamination brought in the past should be restored positively. For consciousness raising against pollution as well as for presentation of the study results on this project, environment related seminar was held twice in cooperation with the counterpart, ENAMI. One was held in the city of La Serena in March, 2002 and another in Santiago in October, 2002 respectively. Both seemed to have attracted the attendance, which counted more than fifty in each case.

9-2 Completing the entire Study, the Japanese Study Team would like to express thanks to ENAMI and related institute for offering valuable data or information and also to the counterparts concerned for cooperative works. Finally, it is desired that Ovalle plant would be literally the model plant of copper ore processing in Chile both in technical and environmental standpoints.

9-3