ANALYSIS OF ALTERNATIVES

Legal name of applicant(s): Boliden Mineral AB

Submitted by: Boliden Mineral AB

Substance: Sodium Dichromate (Na2Cr2O7) [EC 234-190-3; CAS 10588- 01-9]

Use title: The use of sodium dichromate in copper/lead separation in concentrators handling complex sulphide ores.

Use number: 1 ANALYSIS OF ALTERNATIVES

CONTENTS

DECLARATION ...... 4

GLOSSARY OF ABBREVIATIONS ...... 5

1 SUMMARY ...... 8

2 ANALYSIS OF SUBSTANCE FUNCTION ...... 10

2.1 Introduction ...... 10

2.2 Background information on mineral processing ...... 10 2.2.1 General ...... 10 2.2.2 Grinding ...... 10 2.2.3 Flotation process ...... 11 2.2.4 Collectors ...... 12 2.2.5 Depressants ...... 12

2.3 Boliden Area and Garpenberg concentrators ...... 13

2.4 SUBSTANCE FUNCTION ...... 15

3 ANNUAL TONNAGE ...... 15

4 IDENTIFICATION OF POSSIBLE ALTERNATIVES ...... 15

4.1. Description of efforts made to identify possible alternatives...... 15

4.2. Data searches ...... 16

4.3. Consultations ...... 17

4.4. Summary of past research and development on potential alternatives ...... 17 4.4.1 Modification of the Conditions of Flotation ...... 19 4.4.2 Stage-wise Flotation ...... 19 4.4.3 Chloride Leaching ...... 20 4.4.4 Low pH / High Temp...... 20 4.4.5 High pH ...... 20 4.4.6 High Gradient Magnetic Separator ...... 20 4.4.7 Hydrazine ...... 22 4.4.8 Ozone ...... 22 4.4.9 Sulphide, hydrogen sulfite, sodium sulfite, iron sulphite, zinc sulphate, iron sulphate ...... 22 4.4.10 Ferric Chloride/Sodium Thiosulphate ...... 23 4.4.11 Sulphur Dioxide ...... 23 4.4.12 Cyanide Salts ...... 24

4.5. Future Research and Development ...... 25 4.5.1 Reagent Change: ...... 26 4.5.2 Process Change: ...... 26 4.5.3 Cooperation: ...... 26

5. SUITABILITY AND AVAILABILITY OF POSSIBLE ALTERNATIVES ...... 26

5.1. Dextrin ...... 26 Substance ID and properties ...... 29 Technical feasibility ...... 29 Economic feasibility ...... 29 Reduction of overall risk due to transition to the alternative ...... 31

ANALYSIS OF ALTERNATIVES

Availability ...... 31 Conclusion on suitability and availability for Dextrin ...... 31

6. OVERALL CONCLUSIONS ON SUITABILITY AND AVAILABILITY OF POSSIBLE ALTERNATIVES .. 33

ANNEX – JUSTIFICATIONS FOR CONFIDENTIALITY CLAIMS ...... 34

APPENDICES ...... 36

ANALYSIS OF ALTERNATIVES

GLOSSARY OF ABBREVIATIONS

Na2Cr2O7 Sodium Dichromate PbS galena cm centimetre μm micrometre mg/L milligramme per litre % percent EC European Commission CAS Chemical Abstracts Service pH measure of acidity 2¯ CrO4 Chromate anion m metre m3 metre cubed RPE Respiratory Protective Equipment PPE Personal Protective Equipment LEV Local Exhaust Ventilation g/L grammes per litre Cr (VI) hexavalent chromium Cr (III) trivalent chromium IBC Intermediate Bulk Container mg/m3 milligramme per metre cubed mins. minutes conc. concentration

Cr2O3 Chromium Oxide

Cr(OH)3 Chromium Hydroxide Kg/annum kilogrammes per year μg/L microgrammes per litre Kg kilogramme ng/m3 nanogramme per metre cubed mg/kg/d milligramme per kilogramme per day µg/kg/d microgramme per kilogramme per day mg/kg milligramme per kilogramme Cu Copper Pb Lead

Use number: 1 5 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES

NaCN Sodium Cyanide °C degrees Celsius g/t grammes per tonne

SO2 Sulphur Dioxide

ZnSO4 Zinc Sulphate

Na2S Sodium Sulphide R & D Research and Development et al. et alii (and others) e.g. for example i.e. id est (that is) CMC Carboxymethyl Cellulose No. Number Irrit. Irritant STOT SE Specific Target Organ Toxicity Single Exposure Muta. Mutagenic Carc. Carcinogenic Repr. Reproductive toxin STOT RE Specific Target Organ Toxicity Repeated Exposure REACH Registration, Evaluation, Authorisation and Restriction of Chemicals EEA European Economic Area SVHC Substance of Very High Concern SIN List Substitute It Now List WHO World Health Organisation IARC International Agency for Research on Cancer CoRAP Community Rolling Action Plan etc. et cetera (and other things) SEK Swedish Crowns EUR Euro C&L Classification and Labelling inventory Tox. Toxic Corr. Corrosive Sens. Sensitiser Dam. Damage

Zn(CN)2 Zinc Cyanide

Na2SO4 Sodium Sulphate

Use number: 1 6 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES

Zn Zinc g/mol grammes per mole mm Hg millimetres of Mercury HCN Hydrogen Cyanide CN¯ Cyanide ion ppm parts per million

LDLO Lethal Dose Low

LD50 Lethal Dose 50 mmol/kg millimole per kilogramme DNA Deoxyribonucleic Acid

CuFeS2 chalcopyrite

Cu2S chalcocite

CuO2 Copper Dioxide CuO Copper Oxide

FeS2 pyrite HGMS High Gradient Magnetic Separator

O3 Ozone SP Svenska Provningsanstalten t/d tonnes per day CoRAP Community Rolling Action Plan

Use number: 1 7 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES

1 SUMMARY

Boliden is a mining and smelting company that focuses primarily on the production of copper, zinc, lead, gold and silver. It is a multi-national company and has mining or smelting operations in Sweden and Finland, owning also a smelting company in Norway and a mining company in Ireland.

This application for authorisation is concerned with the use of sodium dichromate (Na2Cr2O7) to depress lead sulphide (PbS; galena) in complex sulphide ores, and produce copper and lead concentrates as a result. This occurs at both the Boliden Area and Garpenberg concentrators.

The use is necessary because most of the ore deposits that supply the Boliden Area and Garpenberg concentrators contain mixtures of copper and lead minerals, meaning economic extraction requires separation of the various minerals before smelting. This separation is achieved with sodium dichromate in the copper lead separation circuit in the froth flotation process.

Flotation involves the bubbling of air through the flotation cell to promote the rising through the pulp of hydrophobic minerals. This enables product separation and recovery; and the unfloated material (i.e. components not collected in the froth layer, like gangue and depressed minerals) is forwarded into a downstream cell or circuit or is discharged to the tailings pond. This happens because hydrophobic particles become bound to the surface of these bubbles as the bubbles travel up through the pulp, concentrating in the froth at the surface. Both copper and lead, and other metals, are floated initially to separate them from undesirable gangue material. This is done by the addition of a collector which binds to the surface of the sulfide minerals. After this, and in order to separate the copper from the lead, it is, therefore, necessary to modify one of them to induce it to depress. This occurs on addition of a depressant; Sodium Dichromate in Boliden Area and Garpenberg’s case. Dichromate preferentially binds the collector bound galena (PbS).

The overall process, consequently, exploits properties of the minerals that are easily modified, e.g. surface wettability. Hydrophilic particles are wetted by water and fall to the bottom of the cell, while hydrophobic particles will float to the surface.

Many reagents are available that can act as depressants during froth flotation. The mineralogy of the ores plays a significant role, however, in whether any of these reagents are feasible. Boliden’s processes are adapted to maximise the recovery of metals while having as minimal an environmental impact as possible.

Boliden has undertaken extensive research over several decades in an effort to refine the copper lead separation and also to replace reagents deemed hazardous. These investigations started in the 1950s and continue to the present day. Thus far no reagents, adjustment in the conditions of the flotation or technological modifications to the process have proved to be viable from either one or more of economic feasibility, technical feasibility, availability or risk reduction.

The two main areas investigated to remove dichromate are: reagent change and technology change. To this end, Boliden is in constant contact with reagent suppliers and continues to seek a replacement to dichromate in its processes and process change; introduction of new processes that might lead to dichromate use being discontinued and investigation of new technologies that results in viable concentrates, e.g. current investigations on selective Cu flotation with a high Cu content followed by a bulk-flotation of Cu and Pb. These investigations may ultimately lead to the use of dichromate becoming obsolete.

Use number: 1 8 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES

Tests performed have included reagents that are known to be used in similar processes around the world as well as research from books, scientific articles and Boliden’s own custom projects in the area. The purpose of these studies was to collect all available knowledge on copper lead separation techniques, to avoid duplication of efforts and also to find new methods for better separation. Additionally, Boliden has supported projects on copper lead separation in the university sector in an effort to expand the knowledge base in their continuing search for alternatives.

The differing mineral contents of the ores also introduce a complicating element to the search for an alternative. Boliden must, as a result, test each possible alternative reagent on each of these ores to ensure consistent results. Finding a selective reagent is, therefore, a continuous effort.

Currently the only option that is worth considering for Boliden Area and Garpenberg is the substitution of dichromate with dextrin. Dextrin is a non-hazardous substance that is already used in Boliden concentrators as a depressant for gangue. It is, consequently, technically feasible under the conditions of flotation, available and leads to a risk reduction at the concentrator. There is an increase of lead in the copper concentrate from Boliden Area which leads to a poorer position for the smelter downstream, as the lead dust produced from the copper smelting is a substance with equivalent hazard levels to dichromate.

Moreover, the separation of the metals during flotation is not as good as with dichromate, leading to a significantly worse economic position for both the concentrators. Additionally, given that the risk with the current processes are already reduced to a minimum, a change would consequently represent only a small overall risk reduction potential at the concentrator, while increasing the potential at the smelter.

It is clear, therefore, that there is currently no alternative available, either industrially proven or otherwise, for Boliden Area and Garpenberg. Consequently, the only way to achieve the separation of copper and lead, while ensuring that operations are conducted at an economically acceptable level and in an environmentally responsible way, i.e. minimising waste by maximising the extraction of valuable metals from the ores, is by using sodium dichromate as a lead depressant in the separation circuit.

Boliden is also committed to continuing research and development activities with less hazardous, alternative reagents in an effort to replace dichromate in its processes in the future. In conclusion, Boliden has acknowledged the hazards surrounding the use of sodium dichromate in their processes, even long before the implementation of the REACH regulation. They have endeavoured to replace the reagent, and when failing to do so, have introduced policies to limit any exposure potential for workers or the environment. Prospective replacement candidates are evaluated on a continuing basis, however, the nature of the input ores into the flotation process means that no suitable alternatives have, to date, been identified. This, in turn, means that, given past experience, it is likely going to be a long time before a viable candidate is identified, tested, qualified and industrialised.

Use number: 1 9 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES

2 ANALYSIS OF SUBSTANCE FUNCTION

2.1 Introduction Boliden is a Swedish mining and smelting company, with headquarters in Stockholm, which focuses on the production of copper, zinc, lead, gold and silver. It was founded in 1931 following the merger of Västerbottens Gruvaktiebolag and Skellefteå Gruvaktiebolag. It is a multi-national company and has mining or smelting operations in Sweden and Finland, owning also a smelting company in Norway and a mining company in Ireland. The company owns Aitik mine, the largest copper mine in Europe, and Tara mine, the largest zinc mine in Europe.1 This application for authorisation is concerned with the production of copper and lead concentrates at both the Boliden Area concentrator and at the Garpenberg concentrator from complex sulphide ores, which are a major source of base metals such as zinc, copper, lead and nickel. Complex sulphide ore deposits generally contain several base metals, meaning economic extraction requires separation of the various minerals before smelting. This is achieved using the method of froth flotation which, in this instance, involves the use of sodium dichromate (Na2Cr2O7) to depress lead sulphide (PbS; galena).

2.2 Background information on mineral processing

2.2.1 General Sulphide ores are a major source of base metals such as zinc, copper, lead, and nickel. Complex sulphide ore deposits generally contain several of these metals, meaning economic extraction requires separation of the various minerals before smelting. Mineral processing is used to separate the value minerals, as well as separation of gangue material in the ore, to obtain high-grade concentrates of these metals. Mineral processing can involve four general unit operations: Comminution – particle size reduction by grinding; Sizing – separation of particles by screening and classification; Concentration of the mineral – e.g. by flotation; and Dewatering. In mineral processing the differences in the physical and chemical properties of the minerals like particle size, density, electrical and magnetic properties and surface wettability are important elements that influence the choice of mineral processing method.

2.2.2 Grinding The mineral process begins with the grinding of the ore. Flotation reagents can be added at this point in the process but this depends on the mineralogy of the ore. The ore is mixed with water in the mills and ground. Grinding must achieve high liberation of the target minerals. The goal is to achieve particles that are so small that each contains as close to one mineral type as is possible, thus copper, zinc, lead and gold mineral grains are liberated from valueless minerals (gangue) contained in the ore. Ore can be fed to the grinding mill at sizes of up to a few decimetres in diameter and discharged from the mill circuit to the flotation cells (circuit) at typically between 10-100 μm in size. Grinding

1http://www.boliden.com/

Use number: 1 10 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES of the minerals to such small sizes causes bond breaking to occur, which then gives rise to surface free energy which is available for reaction2 and exposes enough valuable mineral surface so that chemical modifications may occur there, ensuring efficient recovery from the flotation process. In Boliden Area and Garpenberg this grinding is carried out by an autogenous system, that is to say, without the addition of grinding media like steel balls.

2.2.3 Flotation process Froth flotation has been used as a method for concentrating minerals on an industrial scale for many decades, having being patented in 1906,3 and dichromate has been used as a depressant in mineral concentrating since 1912.4 In flotation, bubbles are introduced to the cell and rise through the pulp where they are collected from the surface. Hydrophobic particles become bound to the surface of these bubbles as they travel up through the pulp meaning that the hydrophobic particles are concentrated in the froth at the surface of the cell. To enable these particles to attach, careful consideration of the chemistry of the pulp needs to be made, such as pH. The flotation principle is described in Figure 1.

Figure 1. A diagram of a froth flotation cell. A mixture of ore and water (pulp) [1] enters the cell and is kept homogenous by agitation. Air [2] is passed down a vertical impeller where shearing forces break the air stream into small bubbles. The mineral concentrate froth is collected from the top of the cell [3], while the pulp [4] flows to another cell.5 The overall process depends on the property that hydrophilic particles are wetted by water, whereas air bubbles induced into aqueous slurry will preferentially attach themselves to the surface of hydrophobic particles. These particles are then carried to the surface and form a froth layer and enable its removal for product recovery; and the unfloated material (i.e. components not collected in the froth layer, like gangue and depressed minerals) is forwarded into a downstream cell or circuit or is discharged as waste to the tailings pond.6 Froth flotation, thus, exploits properties of the minerals that it is possible to modify, e.g. surface wettability. Reagents used to promote the formation of the froth phase, that facilitates the removal of particles carried to the top of the flotation cell by air bubbles and allow colliding particles and bubbles to

2Klymowsky I. B., Thesis: The Role of Oxygen in Xanthate Flotation of Galena, Pyrite and Chalcopyrite, 1969, http://digitool.library.mcgill.ca/webclient/StreamGate?folder_id=0&dvs=1389960818906~111 3Kohad V.P., Froth Flotation: Recent Trends, 1998, pp. 18-41. 4Lowry A, Greenway H.H., Australian Patent Office # 5065, 1912. 5http://en.wikipedia.org/wiki/Froth_flotation 6Yarar B., Ullmann’s Encyclopaedia of Industrial Chemistry: Flotation.

Use number: 1 11 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES establish contact more rapidly (in the order of mille to microseconds in relation to sulphide flotation), are called frothers.

2.2.4 Collectors Substances primarily used to induce hydrophobicity in solids and promote adhesion to air bubbles, or oil droplets, are known as collectors. The collector species must bind the particles in a way that it remains immobilised on the surface of the particle and imparts sufficient hydrophobic properties that allow it to withstand the mechanical and dynamic effects of the flotation system. Xanthate anions readily chemisorb on most sulphide containing minerals, rendering them hydrophobic by their addition,7 for example a surface coverage of only 20-40 % is required to induce the flotation of galena under certain conditions.8 In this step of the process both the copper and lead particles react with the collector and both are induced to float. There are many other collectors that can be used in flotation, for example dithiophosphates and thionocarbamates. Boliden’s processes combine several collectors of these with xanthates. The mechanism for the adsorption of a thio-collector onto the surface of galena is not well understood. It is supposed that there is adsorption, with ion exchange between xanthate anions and sulphide, at the surface of the mineral9 and that, under the conditions of flotation, the thermodynamically favoured reaction is chemisorption of the collector to the metal atom in the outermost layer of the sulphide lattice.10

- + 0 PbS + 2X + 2H + ½O2 → PbX2 + S + H2O [1]

- 2- PbS + 2X + 2O2 → PbX2 + SO4 [2]

- 2- + CuFeS2 + X + 3H2O + 4O2 → CuX(s) + 2SO4 + Fe(OH)3 + 3H [3]

- + 0 CuFeS2 + X + H2O + H + O2 → CuX(s) + 2S + Fe(OH)3 [4]

2.2.5 Depressants As both copper and lead sulphides are hydrophobic in the presence of the xanthate collector, and will therefore float, galena removal can only occur when its hydrophobicity is altered such that it preferentially becomes hydrophilic. This requires a further modification at its surface i.e. it must be depressed. An additional reagent is thus used to modify the surface of the galena, impeding its flotation, rendering it hydrophilic. The selection of reagent is based on the intrinsic properties of the specific ores being used in the process, the minerals to be depressed and also that of the minerals that it is desirable they stay hydrophobic. Reagents that perform this task are known as depressants.3 The depressant used in the copper lead concentrate separation step in the Boliden Area and Garpenberg concentrators is sodium dichromate (EC 234-190-3; CAS 10588-01-9). Dichromate, in an aqueous solution, is in equilibrium with chromate11, as shown below, Equation [5].

7Wark I.W., Sutherland K.L., Principles of Flotation, Aust. Inst. of Min. and Met., 1955; Gaudin A.M., Flotation, McGraw-Hill, 1957. 8Klassen V.I., Mokrousov V.A., An Introduction to the Theory of Flotation, Butterworths, 1963. 9Dutra, A. J. B., Espinola A., Sampaio J. O., J. Braz. Chem. Soc., 8(2), 1997, pp. 193-196. 10Buckley A.N., Gong B., Lamb R.N., Woods R., Electrochem. Soc. Proceedings, 2000, pp. 72-83. 11Chambers C., Holliday A.K., Modern Inorganic Chemistry, Butterworths, 1975.

Use number: 1 12 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES

Acid 2- + 2- - 2CrO4 + 2H Cr2O7 + H2O = 2HCrO4 [5] Alkali Given that the aqueous environment in both Boliden Area’s and Garpenberg’s flotation cells is alkaline, the equilibrium is shifted to the left. Dichromate depresses galena (PbS), whilst allowing other sulphidic containing minerals to float. Though the mechanism of this reaction is, again, not fully understood, investigations12 have suggested that the depressive action of chromates and dichromates on galena occurs via the reactions given below, [6] and [7]. It is supposed that an amount of chromate, approximately equal to a monolayer, is adsorbed onto the surface of the galena and that the depressive action arises because of an increase in the surface hydration, which supersedes the ability to float, despite the presence of xanthate.13 At the pH’s of the Boliden Area and Garpenberg processes, depression of 2¯ galena is most pronounced; with CrO4 being adsorbed to xanthate-adsorbed galena. The resultant particle now has a hydrated surface modification with lead/chromate, meaning that it will wet and sediment in the flotation cell.

Little or no xanthate is desorbed from the surface, though it is possible that chromate can oxidise xanthates to dixanthogen, which leads, ultimately, to desorption, and further depression of the galena.14

2¯ + ¯ 3PbS + 11CrO4 + 16H → 3PbCrO4 + 4Cr2O3 + 3SO4 + 8H2O [6]

¯ + 0 3PbS + 5HCrO4 + 5H → 3PbCrO4 + 2Cr2O3 + 3S + 5H2O [7]

2.3 Boliden Area and Garpenberg concentrators The major product of the ores that supply both the Boliden Area concentrator and the Garpenberg concentrator is zinc, with copper, lead, gold and silver incorporated in smaller amounts.

Table 1: Typical assay of the ores supplying the Boliden Area and Garpenberg concentrators. Au g/t Ag g/t Cu % Zn % Pb % Boliden Area 2.0 60 0.4 4.3 0.5 Garpenberg 0.3 128 0.05 4.4 1.7

Table 1, above, shows the assay of the ores supplying the Boliden Area and Garpenberg concentrators and is demonstrative of the fact that value minerals generally occur at low concentration levels in the ores naturally.15 Ores containing such low levels of value minerals cannot be smelted economically without, firstly, concentrating the copper to between 22-25 %

12Okada S., Majima H., Canadian Met. Quart., 10 (3), 1971, pp. 189-195. 13Okada S., Thesis: Studies on the Depressive action of Chromate and Dichromate Salts on Galena, 1970; http://www.researchgate.net/publication/233583184_Depressive_action_of_chromate_and_dichromate_salts_on_gale na 14Ralston J., Min. Eng., 7 (5-6), 1994, pp. 715-735. 15Encyclopaedia of Materials: Science and Technology pp. 1-10.

Use number: 1 13 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES copper content and the concentration of lead must be significantly higher at ~40 % Pb for a poor concentrate to 70 % Pb for a good one.

Boliden Area In the Boliden Area there are currently 3 underground mines and 2 open pit mines supplying the concentrator with the complex sulphide ores. The metals contained in the minerals of these ores are zinc, copper, lead, gold, silver and tellurium. Of these mines, three (Renström, Maurliden Västra and Kristineberg) have ores that contain lead and copper sulphide in concentrations necessitating separation, using sodium dichromate, to ensure an economically viable Pb and Cu concentrate, including the 2 largest of the 5 mines. The ores from the individual mines are processed separately in campaigns. This is because the flotation behaviour of the minerals differs depending on the ore and as such the processing characteristics (pH, etc) need to be tailored to the individual ore types being processed.16 Currently this concentrator processes 1.6 million tonnes of ore per annum. The overall process is represented diagrammatically in Figure 2, below.

Figure 2: A process overview of a concentrator.

Garpenberg Garpenberg processes complex sulphide ores consisting of minerals containing zinc, silver, lead, copper and gold. The ores primarily consist of zinc and lead, with trace amounts of minerals containing the other metals. A new concentrator with a capacity of 2.5 million tonnes of ore per annum was commissioned in 2014. The old concentrator, which was built in 1953, had a capacity of 1.4 million tonnes per annum, at the time of its closing. Currently Garpenberg is mainly supplied

16Baştürkcü H., Yenial U., Kökkılıç O., Yüce A.E., Erdoğan E.B., Beneficiation of Copper, Lead and Zinc Concentrates From Complex Ore By Using Environmentally Friendly Reagents: http://www.arber.com.tr/imps2012.org/proceedingsebook/Abstract/absfilAbstractSubmissionFullContent338.pdf

Use number: 1 14 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES with ore from the Garpenberg mine. In addition, a small amount (roughly 40,000 tonnes per annum) of ore from the Lovisagruvan mine is processed together with the Garpenberg ore.17

The Garpenberg process is structured in a similar way as depicted in Figure 2, except that there is no leaching plant.

2.4 SUBSTANCE FUNCTION

The function of the sodium dichromate (Na2Cr2O7) in the froth flotation process is the depression of galena (PbS) particles by adsorption onto its surface, rendering these hydrophilic. In so doing this allows the separation of different sulphidic minerals. A copper-lead bulk concentrate can, therefore, be separated into a copper concentrate and a lead concentrate using this technique resulting in separate metal concentrates from the complex sulphide ores. This function cannot be rendered unnecessary due to the specific composition and complexity of the ores that are supplied to the concentrator from the surrounding mines, which contain copper, lead, zinc, silver, gold and other metals in varying concentrations, as well as sulphur and gangue materials like talc etc.

3 ANNUAL TONNAGE Annual tonnages of sodium dichromate vary year-on-year depending on which mines are in campaign. A conservative, average, estimated tonnage for Boliden Area is 29 tonnes per year over a 9 year period (2017-2025) and this figure is used in the CSR. The lifespan of the mines are expected to be 11 years, however consumption for the final 2 years (2026-2027) is significantly lower than the preceding 9 years. For Garpenberg the average usage is expected to be 12.6 tonnes over the 17 year projected lifespan of the mines that supply it. These figures are estimated based on current milled ore tonnages; however, the actual usage may fluctuate as it depends on the yield from exploited deposits. Usage, consequently will decrease with current projections, but could potentially increase should new mineral deposits be discovered that require copper lead separation.

4 IDENTIFICATION OF POSSIBLE ALTERNATIVES

4.1. Description of efforts made to identify possible alternatives A list of Boliden’s past research and development activities are included in Appendix 1 of this report. These reports include synopsis of the state of the art at various points in time over the last 50 years, with reviews of the scientific literature as well as comments on the appropriateness of alternatives, investigations of some of these and conclusions on their usefulness for Boliden’s specific ores. An example of one of these is report TM REP 1985-061-85, which is a literature review that summarises available data in the period 1961-1985. The study includes research from books, scientific articles and Boliden’s own custom projects in the area. The purpose of these studies was

17 http://www.lovisagruvan.se/produktion/produktioninfo

Use number: 1 15 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES to collect all available knowledge on copper lead separation techniques, to avoid duplication of efforts and also to find new methods for better separation. Boliden have for several decades attempted to replace sodium dichromate, however, other reagents or techniques tested were not shown to be suitable (more information in section 4.3.2 and chapter 5). For this reason, it is considered necessary to continue the use of sodium dichromate.

4.2. Data searches For the purpose of this report, patent and scientific literature has also been searched. A non- exhaustive list of databases and engines used in the compilation of this report are given in Table 2, below:

Table 2: List of data sources used in the compilation of this report. Source Details Google www.google.com Google Scholar http://scholar.google.co.uk Google Books http://books.google.co.uk/bkshp?hl=en&tab=wp Science Direct (Scopus) http://www.sciencedirect.com/ FreeFullPDF http://www.freefullpdf.com/#gsc.tab=0 ACS http://pubs.acs.org/ ResearchGate http://www.researchgate.net/ Ullmann’s Encyclopaedia http://onlinelibrary.wiley.com/book/10.1002/14356007 Wikipedia http://en.wikipedia.org/wiki/Main_Page Wiley Sciences http://onlinelibrary.wiley.com/browse/subjects Chemspider http://www.chemspider.com PubMed http://www.ncbi.nlm.nih.gov/pubmed WHO IARC Monographs http://monographs.iarc.fr/ENG/Classification/index.php SIN List http://w3.chemsec.org/ Boliden Internal memoranda and reports. ECHA C&L Inventory http://echa.europa.eu/ ECHA Registration Database http://echa.europa.eu/

Search terms included, but were not limited to; froth flotation, copper/lead separation, dichromate in copper/lead separation, alternatives to dichromate in copper/lead separation, separation in froth flotation, industrial scale copper lead separation, etc.

Additionally, Boliden has engaged in extensive research and development to improve their processes over several decades. One of the main reasons for this is their on-going commitment to environmental and worker safety, as well as the need to continually adapt their processes to maximise returns from the ores they process. A list of some of these reports is provided in the annex, and those deemed most relevant were used and referenced throughout this report.

Use number: 1 16 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES

4.3. Consultations Boliden engaged REACHLaw Oy to produce the documents for this application.

Several consultations were undertaken, face-to-face, via teleconference and also by regular e-mail exchanges between both parties, starting in December of 2013. The core period of consultations were held between December 2013 and December 2014.

Meetings were also held with representatives of Boliden’s own smelter, and contacts were made, on behalf of the authors, to any other relevant players downstream by Boliden themselves.

The discussions in these meetings were structured using a preliminary scoping questionnaire and an explanation of the data need and approach. Further discussion throughout the year involved more detailed information provision and documentation.

4.4. Summary of past research and development on potential alternatives A list of Boliden’s past and present research and development activities are included in Appendix 1. A synopsis of these reagents and techniques is provided in the following section.

Boliden is actively involved in R & D work, partnering with Swedish universities to augment their in-house activities. References to this affect are also included in the appendix.

Figure 3: General diagrammatic of the steps involved in implementing suitable reagents.

Figure 3 shows a representation of the steps required to validate any reagent before full manufacturing can begin. Boliden Area also faces additional difficulties in testing as the ores from the 5 mines are processed in campaigns. As stated previously, only 3 of these ores require dichromate treatment and, therefore, any investigations on plant scale must wait until that particular ore is “in campaign”. Based on consultations and a literature search, an initial list of potential alternatives is compiled and listed in Table 3. Further information concerning the suitability of the alternatives 1-12 is given throughout this section. Based on Boliden’s past R&D results, the possible alternatives were then narrowed to alternative 13, whose suitability is further analysed in sections 5.1.

Table 3. Initial list of possible alternatives

Use number: 1 17 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES

Alternative Type Industrial use site Tested by Comments 18 Boliden (Section) 1 Modification of the Process/Technique No information Lab trials 4.4.1 Conditions of Flotation 2 Stage-wise Flotation Process/Technique No information Lab trials 4.4.2

3 Chloride Leaching Process/Technique No information Pilot plant 4.4.3 4 Low pH / High Temp. Process/Technique No information Lab trials 4.4.4 5 High pH Process/Technique No information Lab trials 4.4.5 6 HGMS Process/Technique No information Plant 4.4.6 7 Hydrazine Reagent No information Not tested 4.4.7 8 Ozone Reagent No information Not tested 4.4.9 9 Sulphide, hydrogen Reagent No information Lab trials 4.4.9 sulfite, zinc sulphate 10 Ferric Chloride/Sodium Reagent No information Lab trials 4.4.10 Thiosulphate

11 SO2 Reagent Brunswick Mining Lab trials 4.4.11 and Smelting (Canada) 12 Cyanide Reagent Western Mine, Lab trials 4.4.12 Mira Lake (Canada); San Martin (Mexico); Cerro DePasco, San Cristobel Mahr Tunnel (Peru); Leningradskara, Zolotushinskaia, Berozovskaia, Mizursk (Russia); Doyashiki (Japan); Pandora, (USA) 13 Polysaccharides Reagent Sturgeon Lake, Pilot plant 5.1 (Canada); San (Dextrin) Francisco (Mexico);

18Bulatovic S.M., Handbook of Flotation Reagents: Chemistry, Theory and Practice, Elsevier Publishing, 2007, pp. 379-400.

Use number: 1 18 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES

Uchinotai (Japan)

4.4.1 Modification of the Conditions of Flotation Investigations into the improvement of the copper lead separation process have included the use of different collector reagents to attempt more selective binding for one metal sulphide over the other. One example of such studies comes when tests were performed using Aero 5415, Aero 5416 and Danafloat 371. These reagents show preferential binding to copper, but not lead. The best results from these trials showed that 97 % of the copper floated, however there was also 62 % lead in the froth, resulting in a poor grade of concentrate. As such this was not deemed a technically feasible alternative. In addition to this work, Boliden have collaborated on several occasions with Luleå University. The latest project aims to develop mineral specific collector reagents to be used for selective separation between sulphide minerals. These novel molecules are more mineral specific and, as a result, the use of modifiers such as Na2Cr2O7 may ultimately not be necessary in the flotation process. Though in the very early stages of development, there has been some initial positive results showing some differential flotation behavior of the different minerals with a given collector, or differential flotation behavior of a given mineral with various collectors employed. The specific selectivity, that would be required for Boliden to begin tests on their ores, has not yet been observed. In order to attempt to show high mineral affinity of a collector, it will be necessary for the university researchers to further investigate the flotation conditions in more detail and the behavior of the novel molecules under the conditions of flotation. As such, this is not deemed technically or economically feasible, is not available in the foreseeable future and it is unclear as to what the risk reduction might be should it ever reach a point of industrialization. Another possibility explored for the Garpenberg concentrator was non-separation of the minerals. The assay of the ores from the mine that supplies the Garpenberg concentrator shows that there is 0.05 % copper content. Lead concentrate with this amount of only copper present is marketable, however, a problem exists in that the concentration of silver present makes the concentrate essentially unsaleable. It also means another smelter would need to be found that could potentially process these impure concentrates containing such high silver concentrations; or the concentrate would need to be sold at a poor price point. Furthermore, there would be a loss of any sales from the sale of the copper, silver and other metals which will now be contained in the lead concentrate.19

4.4.2 Stage-wise Flotation Another technique that was trialled was stagewise flotation of first copper and then lead. This technique had been used at the Aspirsa concentrator in Spain, directly preparing the valuable mineral concentrates. The lead was depressed by conditioning with SO2 before copper flotation. The lead was then activated by aeration before lead flotation. In Boliden, this technology was tested

19Internal Boliden report: TM_REP2012/011, 2013.

Use number: 1 19 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES in Garpenberg but was abandoned because it could not produce concentrate grades of sufficient quality.

4.4.3 Chloride Leaching A pilot plant for chloride leaching was constructed in the 1970s-1980s in order to test if lead could be leached from the copper lead bulk concentrate. The testing showed positive results and plans were made to put this method into full scale production. However, on further investigation it was found that this method would not be economically viable as the penalty from the smelter could not be reduced as much as the initial findings suggested. Though the penalty was based on the lead content of the copper concentrate, other problems existed, most notably that other metals remained in the leach residue and could not be recovered.

4.4.4 Low pH / High Temp. One method to elicit separation after the addition of a collector is to selectively desorb it from a mineral surface and remove or destroy it in some way. Xanthates, which are used by Boliden as collectors, can be destroyed at low pH and high temperature. There are several problems with this technique, however, in that dixanthogen, which can itself act as a collector, is produced in the process and there is insufficient data on how degradation actually occurs at different pH’s and temperatures, concentration of metal ions, concentration of oxidising agents etc. Additionally, it was demonstrated that heating of the pulp to temperatures of 100 °C for 5-10 minutes, resulted in the depression of already floated galena when potassium amyl xanthate was used as a collector. In both Boliden Area and Garpenberg the copper lead separation circuits are run at ambient temperature. This coupled with the uncertainty around the mode of action and the fact that the degradation product may act as a collector and float the minerals present, make this technically unfeasible.

4.4.5 High pH High pH allows for the depression of galena by the formation of lead hydroxide on the surface of the mineral. Even at high pH, however, desorption of the collector is slow. In addition, within certain pH ranges lead carbonate can be formed via reaction of the galena surface with atmospheric carbon dioxide. This technique is not deemed viable as desorption is slow, even at very high pH, meaning it is not technically feasible on an industrial scale under normal conditions of flotation.

4.4.6 High Gradient Magnetic Separator

Galena (PbS) and chalcocite (Cu2S) are diamagnetic, meaning that they will not be attracted by an external magnetic field, whereas bornite (Cu5FeS4) and chalcopyrite (CuFeS2) are paramagnetic and antiferromagnetic respectively.20 Because of these differing magnetic susceptibilities there exists the possibility that some minerals may be separated when a strong enough magnetic field is applied to them.

20Pearce C.I., Pattrick R.A.D., Vaughan D.J., Reviews in Mineralogy & Geochemistry, 61, 2006, pp. 127-180.

Use number: 1 20 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES

Kindig and Turner21 filed a patent in 1979 concerning the magnetic separation process for the beneficiation of sulphide ores. Specifically the invention related to the removal of gangue materials, leaving only valuable metal sulphides behind. This was achieved by a reaction on the surface of the minerals with a metal containing compound, resulting in an alteration of the surface characteristics of the minerals. This surface modification meant that the sulphide minerals present in the pulp became susceptible to a physical separation using a magnetic field. This reaction is not specific, however, for individual sulphide ores meaning the magnetism is imparted on all metal sulphides. As a result, the selectivity required to separate the minerals into their respective concentrates was not present. Lin et al.22 studied the capture of metallic copper by high gradient magnetic separation at different flow rates and with, or without, a matrix from wastewater. They concluded that high capture efficiencies (> 95 %) of CuO2 and CuO were possible if flow rate was carefully monitored and a matrix was present. Svaboda et al.23 investigated the possibility to improve the recovery of copper and lead from flotation tailings by magnetic and gravity separation techniques. Their trials included analysis of the effect of the magnetic field; flow-rate and slurry density; and sample desliming. Despite the low magnetic susceptibilities of the minerals, they found it was possible to recover up to 70 % of copper and 50 % of lead into the magnetic concentrate. Additionally, they found that smaller particles (10 μm) were not recovered at all. Ultimately, however, they found that the quality of the concentrate could not be improved to an acceptable level by using magnetic separation alone. Boliden performed studies into the feasibility of magnetic separation of copper and lead sulphide minerals in the 1970s and 1980s. It was found that this technique could not replace chemical treatment of the ores, as when a field strength of 10 kGauss and flow rate from 115 to 146 mm/s were used a magnetic concentrate with more than 90% Cu was obtained, with less than 10% Pb yield. Results worsened when finer particle were tested.24 It, however, provided some improvements to the cleaning of the resulting lead concentrate from iron containing minerals (pyrite; FeS2) at Garpenberg, compared to the process that was employed there at that time. This was required because the levels of FeS2 in the lead concentrate were above 10 %, thus incurring penalties from the smelter. It was run in the Garpenberg plant for several years but was eventually replaced by other improvements in the copper lead cleaner circuit. This method, however, did not show potential for use with any other ores. This technique proved to be technically unfeasible, as it did not provide a separation that would result in concentrates of sufficient quality to be deemed a viable alternative. Moreover, it was found that the ores supplying the concentrators in Boliden Area and Garpenberg are naturally too fine to elicit acceptable separation.

21Kindig J., Turner R., Patent PCT/US1979/000475, 1979. 22Wu W., Wu C., Hong P.K.A., Lin C., Environmental Technology, 32 (13), 2011, pp. 1427-1433. 23Svaboda J., Guest R.N., Venter W.J.C., J. S. Afr. Inst. Min. Metall., 88(1), 1988, pp. 9-19. 24Internal Boliden Report: TM_REP1985/058, 1985.

Use number: 1 21 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES

4.4.7 Hydrazine

Substance ID EC Number CAS Number Properties Flam. Liq. 3; Acute Tox. 3; Skin Corr. Hydrazine 206-114-9 302-01-2 1B; Skin Sens. 1; Carc. 1B; Aquatic Acute 1; Aquatic Chronic 1

Hydrazine can form a hydrophilic layer on the surface of galena. It is thought that hydrazine acts to desorb the collector from the surface of the galena, causing it to be depressed. Hydrazine has a harmonised classification of Carc. 1B, as well as it being a skin corrosive, skin sensitiser, acutely toxic and acute and chronic for the aquatic compartment. As such, it is classed as an SVHC substance with an equivalent level of concern to those properties of sodium dichromate. Its use would not, therefore, result in any risk reduction for either workers or the environment.

4.4.8 Ozone

Substance ID EC Number CAS Number Properties Ozone 233-069-2 10028-15-6 Ox. Gas 1; Skin Irrit. 2; Eye Irrit. 2; Acute Tox. 1; STOT SE 3; Muta. 2; STOT RE 2; Aquatic Acute 1

Ozone was used, in literature sources, for the separation of copper and nickel by de-absorption of the collector. It was suggested that 0.1 Kg per tonne of O3 would be required for desorption of xanthate from the surfaces of chalcopyrite and nickel minerals. This method was never trialled by Boliden and is not considered a technically viable solution because it would require the use of an ozone generator; ozone being a highly toxic gas in its own right. Indeed, the self-classification of O3 would suggest that there would be no risk reduction compared to dichromate.

4.4.9 Sulphide, hydrogen sulfite, sodium sulfite, iron sulphite, zinc sulphate, iron sulphate The mode of depressive action of the sulphite ion on pyrite was studied by researchers and it was found that oxygen of the sulphite directly bonds to the sulphur at the surface of the mineral. This prevents xantogen-mineral complex formation, and thus the mineral is depressed. This blocking mechanism is represented diagrammatically in Figure 4, below.

- - O S - S + M SO3 M O S - + S S O

Figure 4: Diagram showing the mechanism that prevents xantogen-mineral complex formation.

Use number: 1 22 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES

Laboratory tests showed inconsistent results when investigated. Additionally, sodium sulphide proved difficult to process, one of the reasons being its low solubility. Therefore, this is considered not technically feasible on an industrial scale. For sodium sulfite, iron sulphite, zinc sulphate, iron sulphate the tests were carried out at varying pH’s, however, the selectivity of the reference experiment (dichromate at natural pH) could not be replicated.

4.4.10 Ferric Chloride/Sodium Thiosulphate

Substance ID EC Number CAS Number Properties Iron Trichloride 231-729-4 7705-08-0 Acute Tox. 4; Skin Corr. 1B (Self-Classified) Sodium Thiosulphate 231-867-5 7772-98-7 Not Classified

Laboratory tests gave inconsistent results. Ultimately, however, this process suffers from many disadvantages; namely there are a relatively larger number of reagents required than with the dichromate process; ferric chloride is corrosive and thiosulphate was unstable under the process conditions. The inconsistent results mean that this is not considered technically feasible on an industrial scale.

4.4.11 Sulphur Dioxide

Substance ID EC Number CAS Number Properties Sulphur Dioxide 231-195-2 7446-09-5 Press.Gas; Skin Corr. 1B; Acute Tox. 3

Table 3, above, reveals that sulphur dioxide (SO2) is used industrially in the separation of copper and lead in concentrators around the world.

Boliden has undertaken several investigations into the use of SO2 as an alternative depressant during R & D work in copper lead separation since the early 1970’s and 1980’s. Sulphur dioxide behaves analogously to that of the sulfites above. Investigations into galena behaviour with SO2 showed that the impact of the gas on the flotation behaviour of galena is linked to the formation of insoluble, and therefore depressing, thio-salts on the surface. Research showed that flotation activity is low immediately after charging of the SO2 additive. When flotation was allowed continue for a longer time, however, atmospheric oxygen began to oxidise the surface and break up the sparingly soluble salts on the galena surface, meaning that the galena began to float. There is still, nevertheless, a tendency towards depression of galena.

Investigations with SO2 continued when it was trialled on a laboratory scale. Results showed that it required pulp warming in order to produce acceptable concentrates. The temperature range involved was between 10-80 °C which was performed using immersion heaters. At temperatures above 50 °C there is an improvement in the selectivity of the copper lead compared to SO2 alone, but Zn concentration increases in the copper concentrate.

Use number: 1 23 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES

Overall the laboratory tests carried out by Boliden found that sphalerite was depressed by the addition of SO2; galena showed a worse separation and the precious metals showed a large difference in flotation behaviour depending on the ore that was sampled. There were also problems with foaming.

SO2 was also tested in conjunction with sodium dichromate or cyanide as co-reagent, this giving an improvement in selectivity between copper and lead. The overall conclusions drawn from these tests were that an acceptable copper lead separation was not achieved with this method. One of the reasons for this was that the Zn concentration increased in the copper concentrate. Gold and silver minerals present were, to some extent, also solvated meaning the loss of these metals when cyanide was used as a co-reagent.

Additionally, the different ores were affected by SO2 treatment in different ways, depending on the predominant metal ion reactivity compared to the thio-ion. Moreover, when this method was trialled in Garpenberg, it was found that, at higher temperatures, the copper flotation was too slow for the industrial process.

These reasons mean that SO2 cannot be considered a viable solution for Boliden.

4.4.12 Cyanide Salts

EC CAS Substance ID Properties Number Number

Sodium cyanide Acute Tox. 2; Acute Tox. 1; Eye Dam. 1; 205-599-4 143-33-9 (Self-Classified) Aquatic Acute 1; Aquatic Chronic 1 Salts of Hydrogen Acute Tox. 1; Acute Tox. 2; Aquatic Acute Cyanide 1; Aquatic Chronic 1 (Harmonised C&L)

Cyanide is used in flotation separation circuits when the amount of chalcopyrite in the copper lead bulk concentrate is substantially greater than the amount of galena, which is to say a ratio of over 2:1 and involves the depression of copper minerals, instead of lead. Additionally, the concentrate must not contain secondary copper minerals and the concentrate must be sufficiently clean, otherwise a low, unmarketable grade of copper will be obtained.19 Disadvantages associated with this method also include the fact that, depending on the ore, cyanide consumption is high, with ranges from 300-6000 g/t reported.19 Furthermore, if native gold is present in the concentrate, cyanide will dissolve it, resulting in substantial losses of the precious metal. In order to avoid the loss of these metals, cyanide is generally used as a complex with ZnSO4 in a basic solution.

ZnSO4 + 2NaCN ⇌ Zn(CN)2 + Na2SO4 [8]

Table 3 above, reveals that several mines around the world employ this method in copper lead separation. Interestingly it also shows that at the Cerro DePasco mine in Peru, a mixture of NaCN/ZnSO4 at pH 11 is used, however, this is changed to Na2Cr2O7 when there is high Pb content in the ore.

Use number: 1 24 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES

Boliden has undertaken several tests using cyanide as an alternative depressant during R & D work in copper lead separation since the early 1970s.25 Cyanide was used previously in two of Boliden’s concentrators for the depression of pyrite, pyrrhotite and spharerite but was replaced in the mid- eighties.

Conclusions34 on the experimental results were that the separation process worked well, but was still not recommended as Zn minerals depressed with Cu which resulted in increased penalties at the smelter. The process has also other drawbacks as the precious metals were solvated in the process water.

As mentioned above, Boliden also undertook laboratory tests using cyanide in conjunction with SO2 as an alternative26 in 1998, when they tested ore from Petiknäs Norra mine in copper lead separation. The conclusions drawn at that time were that cyanide depression of copper provided improved selectivity between copper and lead. Depression of copper was particularly suitable because the content of copper was far greater than the content of lead in copper lead concentrate. Further trials were suggested with higher NaCN content ( > 600 g/t).

Cyanide is not a technically feasible alternative for the separation of minerals in the Garpenberg concentrator. This is because the content of lead in the form of galena (PbS) is far greater than the content of copper in the copper lead bulk concentrate. Cyanide is only a viable alternative technology when the amount of chalcopyrite (CuFeS2) in the copper lead bulk concentrate is substantially greater than the amount of galena, that is to say a ratio of 2:1 or more. In the Boliden Area concentrator, of the 3 mines that supply ores to the concentrator it has been postulated that cyanide could be feasible for the separation of copper and lead from the ores of 1 of these mines. For the remaining 2 mines, which are the larger of the mines that supply ores requiring copper lead separation to the Boliden Area concentrator, it is not practical as these ores contain concentrations of precious metals which would be lost to the process water, which then becomes more difficult to recover, if it is possible. Though the third mine could, conceivably, use cyanide as a depressant, problems arise in the need to switch between reagents for the different mines, which is unmanageable in Boliden Area with their current processes. Additionally, dichromate would still be required for copper lead separation for the mines whose ores contain precious metal minerals. The use of cyanide, consequently, would not reduce the overall risk in the process, even though there could possibly be a reduction in the total tonnages of dichromate used.

4.5. Future Research and Development Work to find a substitute for dichromate is an on-going project within the Process Technology department of Boliden. This work will continue until a feasible alternative has been developed, or until external cooperation will introduce a feasible alternative, and will focus on 2 aspects: 1) Reagent change and 2) Process change.

25Internal Boliden Report: TM_Rep 1973-003, 1973. 26Internal Boliden Report: TM_Rep 1998-037, 1998.

Use number: 1 25 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES

4.5.1 Reagent Change: Boliden continues to test less hazardous alternative reagents to evaluate any possibility that they are able to replace dichromate. To this end, they have commenced a partnership with Svenska Provningsanstalten (SP; the Swedish Technical Inspection Agency), so that they will undertake a more in-depth literature review to propose theoretically appropriate replacements for dichromate in the flotation process. This process will involves chemical analysis of the different ore samples, followed by small scale laboratory trials of possible replacements. Additionally, work still continues to further understand and develop the use of cyanide as a depressant. This has involved the funding of a master’s thesis which will be published shortly. Nevertheless, such investigations are unlikely to yield viable industrial scale alternatives for the foreseeable future. Furthermore, Boliden is in constant contact with several reagent suppliers and continues to seek a solution to the use of dichromate in its processes. To this end, they have already investigated several of their suppliers’ selective reagents without success.

4.5.2 Process Change: Boliden has also tested other processes for the separation of Pb and Cu. Unfortunately, however, these have not yet yielded any sustainable results. Current investigations involve performing a selective Cu flotation with a high Cu content followed by a bulk-flotation of Cu and Pb. It is hoped that this will result in a bulk Cu/Pb concentrate with metal ratios that simplify the downstream separation of Cu and Pb. In this way it is possible that the use of dichromate will not be required. Garpenberg, Renström, Maurliden and Kristineberg ores all have differing mineral contents that contain both copper and lead. Boliden must, as a result, test each possible alternative reagent on each of these ores to ensure consistent results. Finding a selective reagent is, therefore, a continuous effort, and has been for many decades.

4.5.3 Cooperation: In an effort to broaden the knowledge base for R&D work, Boliden has established a close relationship with several Swedish universities, including Luleå University of Technology, LTU. Furthermore, Boliden have also entered into a partnership with Svenska Provningsanstalten to broaden the knowledge base around the search for alternatives.

5. SUITABILITY AND AVAILABILITY OF POSSIBLE ALTERNATIVES

5.1. Dextrin Since the early 1950s Boliden has attempted to find a more innocuous depressant, and as such they have undertaken considerable research and development involving Dextrin (EC 232-675-4; CAS 9004-53-9), which is produced for industrial use by pyrolysis or roasting of starch, as a selective lead depressant in copper lead separation during flotation.

Use number: 1 26 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES

Indeed, dextrin has been widely investigated as a depressant in flotation.27

One such example of testing on industrial ores comes from a report by Drzymala et al.28 in their investigation of Dextrin in the removal of lead minerals from the copper ore flotation plant in Lubin, Poland. They found that, while in the absence of any depressant there was negligible separation between copper and lead minerals, on addition of dextrin, at pH 8, separation increased. Overdosing with dextrin, however, led to a decrease in recovered metal from the froth, though selectivity was maintained.

They concluded that polysaccharides could be used, industrially, for the removal of lead minerals from Polish copper industrial concentrates containing copper sulphides, galena and bituminous shale. Additionally, in this investigation, with dextrin as the depressant and xanthate as the collector, they were able to provide froth concentrations with up to 80 % copper recovery, and up to 80 % Pb recovery in the tailings.

Boliden’s investigations included examination of reaction parameters, e.g. differing pH ranges with different ore sources, several modifiers to regulate pH at varying concentrations and various collectors. Indeed, Boliden has been using dextrin in their processes for the depression of gangue materials for many years, and, except for dichromate, it is the method that they have most experience with. Additionally, there will not be a need to have major changes in the concentrator when using Dextrin instead of dichromate. It is for these reasons that Boliden see Dextrin as the only viable polysaccharide alternative for their process.

Garpenberg

Research and development work carried out on the Garpenberg ores in 2011 show that the silver content of the lead concentrate increases by about 33 %, when using dextrin instead of dichromate. If this were to be replicated on plant scale it would have a knock-on effect for Boliden from 2 standpoints: (1) loss of any profit from the sale of the silver metal contained in the lead concentrate and (2) the reduction in the quality of the concentrate means that penalties will be imposed by the smelter, reducing the profitability of the lead concentrate. Consequently, lead concentrates that contain such a high silver content are either: unsaleable on the market; offloaded at a poor price point; or require a smelter in a position to manage such large amounts of silver.

With the opening of the new concentrator, which has only entered full production in August 2014, recent trials suggest that, though the situation is improved in the area of silver content in the lead concentrate compared to the trials in the old concentrator, there is still a significant drop in the copper grade from 20 % to just over 14 %. Typical recoveries from experimental tests are shown in Table 4 below. Additionally, a substantial drop in copper recovery occurs, from 56 % to 40 %.

27(a) Liu Q., Laskowski J.S., Int. J. Miner. Process, 27(2), 1989, pp. 147-155; (b) Bhaskar R.G., Holmgren A., Forsling W., J. Colloid Interface Sci., 193, 1997, pp. 215-222; (c) Liu Q., Zhang Y.H., Int. J. Miner. Eng. 13(13), 2000, pp. 1405-1416; (d) Lopez V.A., Celedon C.T., Song S., Cabrera A.R., Laskowski J.S., Int. J. Miner. Process., 17, 2004, pp. 1001-1006; (e) Wenqing Q., Qian W., Fen J., Congren Y., Ruizeng L., Peipei W., Lifang K., Int. J. Mining Sci. Tech., 23, 2013, pp. 179-186; and references contained therein. 28Drzymala J., Kapusniak J., Tomasik P., Int. J. Miner. Process., 70, 2003, pp. 147-155.

Use number: 1 27 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES

Table 4: Assay of the concentrates from the Garpenberg concentrator with sodium dichromate and dextrin as depressants in early trials at the new concentrator. Sodium Dichromate Gold Silver Copper Zinc Lead

(g/tonne) (g/tonne) (%) (%) (%) Ore 0.3 128 0.05 4.4 1.7 Assay Copper 104 31360 20.0 7.7 22.2 Lead 1.8 2065 0.31 4.6 70

Dextrin Gold Silver Copper Zinc Lead (%) (g/tonne) (g/tonne) (%) (%) Ore 0.33 128 0.05 4.4 1.7 Assay Copper 104 31360 14.3 7.7 22.2 Lead 3.2 2065 0.63 4.6 70

Furthermore, as the concentrator is new and none of the processes are fully optimised or stable yet, not enough information is known about the overall effects that dextrin might have as a depressant on an industrial scale, though it is clear that the results for copper are worse and it is likely lead results will mirror these. Furthermore, for the purposes of this report, the precious metals recovery is assumed to be the same with dextrin use as it is for dichromate. The reality, however, is that, like Boliden area, dextrin is likely to result in more precious metals being lost, adding to the overall financial losses for Garpenberg. As such, continuing investigations are required.

Boliden Area

A change to dextrin would result in changes in the copper, lead, silver and gold levels contained in the concentrates, as outlined in Table 5, below, which gives a typical assay of the concentrates resulting from experimental tests.

The amount of lead in the copper concentrate would approximately double compared to the current process with dichromate. Apart from economic losses, a change to dextrin will result in twice as much dust produced during the smelting process. The smelter that currently processes the Boliden Area copper concentrate is already nearing the limit of its abilities in terms of risk management measures. If there was too much lead in the concentrate, it is likely the smelter would rather source from alternative suppliers, or need to blend concentrates from different sources in order to minimise the concentration of lead.

Table 5: Assay of the concentrates from the Boliden Area concentrator with sodium dichromate and dextrin as depressants. Sodium Dichromate Gold Silver Copper Zinc Lead

(g/tonne) (g/tonne) (%) (%) (%) Ore 2.0 60 0.4 4.3 0.5 Assay Copper 29 2423 24.78 4.18 8.88 Lead 3.6 1785 2.97 7.52 40.49

Use number: 1 28 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES

Dextrin Gold Silver Copper Zinc Lead (%) (g/tonne) (g/tonne) (%) (%) Ore 1.98 63.3 0.42 4.33 0.47 Assay Copper 27 2153 23.23 4.30 11.04 Lead 5.4 2231 4.05 7.09 35.64

Substance ID and properties Dextrin (CAS 9004-53-9) is not a hazardous substance or mixture according to Regulation (EC) No. 1272/2008, nor is it classified as dangerous according to Directive 67/548/EEC.

Dextrin is not contained on any list that would suggest it is a substance of concern (e.g. SIN list, Trade Union Priority List of SVHC, REACH Candidate List, CoRAP, etc.) or, to the best of our knowledge, is it prohibited or restricted by any member state authority.

Additionally, dextrin is not listed as a WHO Acute Hazard, IARC carcinogen or is it contained on other international lists of substances of concern.

Technical feasibility Chemically, this reagent is useable under the normal conditions of the froth flotation process, i.e. an aqueous alkaline environment.

Garpenberg

Though there is a decrease in the concentration of copper in the copper concentrate as a result of dextrin treatment, and an increase in the copper concentration of the lead concentrate, the concentrates are still saleable. Therefore, dextrin is a technically feasible alternative for Garpenberg’s concentrator.

Boliden Area

Though there is an increase in the concentration of lead in the copper concentrate as a result of dextrin treatment, the concentrates are still saleable. Therefore, dextrin is a technically feasible alternative for Boliden Area’s concentrator.

Economic feasibility Garpenberg

The change-over to using dextrin in copper/lead separation in Garpenberg will also result in two main economic impacts for the concentrator in comparison with the continued use of sodium dichromate: 1. There will be a net revenue reduction from the metals contained in the lead and copper concentrates, as a result of changes to both the payable metal and the penalised metals in

Use number: 1 29 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES

the concentrates. The value of this net revenue reduction will vary from year to year and it is derived from Boliden’s own programme, which calculates the net revenue based on the yearly production plan. 2. There will be a benefit associated with the lower operational costs of using dextrin. The operational cost will be lower per milled tonne of ore, and the annual cost will therefore also vary from year to year depending on the milled tonnage. The net present value of the cost to Garpenberg over the full temporal scope is .

Boliden Area

The change-over to using dextrin in copper/lead separation in Boliden Area will result in three main economic impacts for the concentrator in comparison with the continued use of sodium dichromate: 1. There will be a net revenue reduction from the metals contained in the lead and copper concentrates, as a result of changes to both the payable metal and the penalised metals in the concentrates. The value of this net revenue reduction will vary from year to year and it is derived from Boliden’s own programme, which calculates the net revenue based on the yearly production plan. 2. There will be a cost associated with an increase of the TC paid to the smelter for the lead concentrates by per tonne (equivalent to per tonne). 3. There will be a benefit associated with the lower operational costs of using dextrin. The operational cost will be lower per milled tonne of ore, and the annual cost will therefore also vary from year to year depending on the milled tonnage. The net present value of the cost to Boliden Area over the full temporal scope is

Rönnskär

There are also costs associated with a change from dichromate to dextrin for the smelter, as the assay of the concentrates will be different. This means that the smelter will have 2 possible scenarios to consider should Garpenberg change to dextrin. Continue to source poorer quality lead concentrates from Garpenberg, or source high quality lead concentrates from external concentrators.

1. Rönnskär will continue to source from Garpenberg, but will suffer a loss in revenue of per tonne for 40,000 tonnes. This equals to per year, which is equivalent to per year.

2. If Rönnskär source externally, freight compensation costs for the 40,000 tonnes of lead concentrates purchased from external mines every year will be at per tonne. In addition, Garpenberg needs to sell its lead concentrate to others and need to bear the freight compensation cost of per tonne for 40,000 tonnes. The additional cost per year will therefore be , which is equivalent to per year.

The net present value of the cost to the Rönnskär smelter over the full temporal scope is from Only scenario 2 will have an economic impact on Garpenberg, which is .

Use number: 1 30 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES

Reduction of overall risk due to transition to the alternative Dextrin is not a hazardous substance or mixture according to Regulation (EC) No. 1272/2008, nor is it classified as dangerous according to Directive 67/548/EEC. As such there could be a slight reduction in the risk undertaken at the concentrators; however, as the dichromate is used in a closed system, and worker contact with the dichromate is already quite limited, this risk reduction would be minimal.

The increased concentration of lead in the copper concentrate, however, would lead to a worsened situation for the smelter, as an increase in ash is produced during the smelting process, meaning there will be a higher health concern for workers there.

If one takes a conservative approach by assuming that all the health and environment impact of continued use of sodium dichromate will be eliminated by changing to dextrin, the overall benefit for Boliden Area and Garpenberg concentrators will be .

Availability Dextrin is available and affordable in specifications that would be suitable for use.

Conclusion on suitability and availability for Dextrin

Table 6: Summary of the conclusions reached on Dextrin as an alternative.

Criteria Conclusion Boliden Area Garpenberg Technical feasibility Technically feasible Technically feasible Economic feasibility The net present value in 2014 of the The net present value in 2014 of the cost to Boliden Area would be: cost to Garpenberg would be: . Depending on what Rönnskär will do, there may be an additional cost to Garpenberg, which would be: . Reduction of overall The use of dextrin will result in an The results when using dextrin for risk due to transition increased concentration of lead in the separation shows that the copper to the alternative copper concentrate leading to an concentrate is worse than with increased health concern for the sodium dichromate. smelter. Additionally, the risk with the Additionally, given that the risk with current process is already reduced to the current process is already a minimum. Therefore, any risk reduced to a minimum, a change reduction potential in transitioning would consequently represent only a to this option is very low. small overall risk reduction potential

Use number: 1 31 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES

at the concentrator. The maximum potential benefit of the ceased use of sodium dichromate The maximum potential benefit of is from the ceased use of sodium dichromate is from

Availability Available Available Conclusion The change to Dextrin for Boliden The change to Dextrin for Area, while technically feasible, is Garpenberg, while technically economically unfeasible and feasible, is economically unfeasible ultimately does not result in an and, therefore, it cannot be overall risk reduction as there is an considered a suitable alternative. increase in lead dust production at the smelter. Therefore this alternative cannot be considered suitable.

Use number: 1 32 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES

6. OVERALL CONCLUSIONS ON SUITABILITY AND AVAILABILITY OF POSSIBLE ALTERNATIVES One of the key environmental goals of Boliden is to ensure that their operations are conducted with environmental responsibility, which entails continuous work towards reducing any negative impact of its operations. This is achieved by extracting minerals and producing high-quality metals in a cost-effective and sustainable manner, in order to meet the market’s demand and thereby create value for its shareholders. Efficiency in the process and maximisation of the recovery of the metals that are mined are key factors when considering this goal. Boliden, having performed research over the course of several decades on most of the known industrial alternatives in copper lead separation in order to find a solution to the use of dichromate, concluded that none of these are suitable given the nature of the ores that supply these concentrators. In section 4.4.1 to 4.4.12 there is a brief overview of many alternatives that were investigated by Boliden, and that failed for a variety of reasons. Dextrin, in section 5.1 was looked into as the main possible replacement to sodium dichromate. Experimental results, from the lab, and also from plant tests in both Boliden Area and Garpenberg, have shown that dextrin, though it can produce concentrates of saleable quality, is uneconomical, not only for the 2 concentrators involved, but also for the smelters downstream. There is, therefore, no alternative available, either industrially proven or otherwise. Consequently, the only way to achieve the separation of copper and lead, while ensuring that operations are conducted at an economically acceptable level and in an environmentally responsible way, i.e. minimising waste by maximising the extraction of valuable metals from the ores, is by using sodium dichromate as a lead depressant in the separation circuit. As is also demonstrated by the CSR accompanying this application, any potential risks to worker safety or environmental releases are currently strictly controlled and pose very little risks. As a result, the use of an alternative reagent or technology will not have any discernible benefit to potential health impacts for workers in the concentrators, and could, in the case of increased production of lead dust in the smelter, lead to adverse impact for worker health there. Nonetheless, Boliden is committed to research and development activities with less hazardous alternative reagents in an effort to replace dichromate in its processes. To this end they have partnered with Swedish Universities and also Svenska Provningsanstalten to broaden the knowledge base around the search for alternatives.

Use number: 1 33 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES

ANNEX – JUSTIFICATIONS FOR CONFIDENTIALITY CLAIMS

Page Justification for blanking number 30-32 Demonstration of Commercial Interest Boliden wishes to keep the figures regarding the annual and the total economic impact confidential. This since Boliden is a public listed company (the Boliden share is listed on the NASDAQ OMX Stockholm Exchange). Demonstration of Potential Harm The potential economic impact is significant and details on this economic impact could be regarded as share price sensitive information which must be disclosed to the market in accordance with certain rules and principles. If ECHA plans to make these details public, Boliden would like to be informed in advance. Limitation to Validity of Claim The claim for confidentiality on the information in this justification is 10 years. 30 Demonstration of Commercial Interest For commercial reasons, Boliden wishes to keep confidential the details regarding: 1. Boliden´s Long term TC and RC´s for Copper and Lead concentrates 2. Information on other suitable lead concentrates from competitive mining companies for Rönnskär 3. TC or RC loss due to downgraded qualities of Copper and Lead concentrates 4. Additional transport costs related to sourcing other lead concentrates and selling Garpenberg lead concentrates externally 5. Economic impact on Rönnskär, Boliden Area and Garpenberg split per year

Boliden never publishes these kinds of internal long term conditions and transport costs or key suppliers officially. Revealing this information to our suppliers of concentrates will be beneficial for the supplier and it would put Boliden in a worse negotiation position. Demonstration of Potential Harm Revealing the information claimed confidential in this justification will put Boliden in a worse negotiation position in case Boliden would negotiate the commercial terms with the suppliers of

Use number: 1 34 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES

external lead concentrates suitable for Rönnskär. There are limited qualities suitable for Rönnskär and the owners of these qualities will be in a good negotiation position in case they know that Rönnskär and in the end Boliden is dependent on them. Limitation to Validity of Claim The claim for confidentiality on the information in this justification is indefinitely. 30 Demonstration of Commercial Interest Justification for confidential material regarding Rönnskär. For commercial reasons, Boliden wishes to keep confidential the details regarding Rönnskär’s potential alternative sources of lead concentrate and the costs and losses that Rönnskär could suffer from processing concentrates of lower quality. Operating costs on this level is never presented in annual reports or published officially. Revealing this information to our suppliers of concentrates will be beneficial for the supplier and it would put Boliden in a worse negotiation position. Publish this kind of information officially can lead to lowered revenues to the smelter and in the end closing of business. Demonstration of Potential Harm Rönnskär’s ability to achieve reasonable terms in a negotiation will be significantly impaired if it becomes known who the potential suppliers of high quality concentrates are and what cost increases Rönnskär suffers from processing concentrates of lower quality. In the concentrate market, knowledge of impurity capacity is sometimes used to produce blends filling up impurities just to the limit where penalties start to apply. This affects the revenue of the smelter. Limitation to Validity of Claim The claim for confidentiality on the information in this justification is indefinitely.

Use number: 1 35 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES

APPENDICES Appendix 1: List of research and development work carried out by Boliden in the area of copper/lead separation over several decades.

Year Reference List of Boliden internal reports on copper and lead separation Author

1950 TM_REP1950/022 Koppar-bly-separation - en laboratorieundersökning / Delrapport 1 Sundkvist Gustaf 1957 TM_REP1957/051 Beträffande Cu-Pb-separation i Blyklippen Fahlström Per H

1960 TM_REP1960/014 Kristineberg / Magnetseparation av svavelkisavfall Öyasäter Olav Renström / Separation av kopparbly-koncentrat / 1961 TM_REP1961/004 Laboratorieundersökning Brooks S D Bolidenmalm / Koppar - Selen - Arsenik - Vismut - separation / 1962 TM_REP1962/001 Separation av vismut Brooks S D 1962 TM_REP1962/004 Renström / Koppar-bly-separation med natriumsulfit + ferrosulfat Walchshofer Ernst Renström /Cu-Pb-separation med FeSO4 och Fe2(SO4)3 samt Cl-jonernas 1962 TM_REP1962/006 inverkan Walchshofer Ernst Renström / Separation av Renström kopparbly-koncentrat / Kampanj i 1962 TM_REP1962/053 försöksverket (nr 421) Brooks S D 1962 TM_REP1962/063 Renström / Separat behandling av kopparblyreturgods Öyasäter Olav Bolidenmalm / Separation av vismut - arsenik / Detaljprovtagning och 1962 TM_REP1962/066 försökskampanj Öyasäter Olav 1965 TM_REP1965/039 Separationsförsök på Jones separator Marklund Olle 1965 TM_REP1965/067 Separation med ånga Premfors Stig Långdal / Separation av kopparhaltig blyslig i kopparslig och blyslig / 1966 TM_REP1966/042 Kostnadskalkyl Fahlström Per H 1966 TM_REP1966/065 Kopparslig/Separation koppar-vismut Mattson 1967 TM_REP1967/085 Koppar-bly separation vid olika lagring Anttila Alrik

1970 TM_REP1970/069 Järnoxid / Magnetisk anrikning / Rening från icke järnmetaller Göransson Torbjörn 1970 TM_REP1970/102 Sala våtmagnetiska motströmsseparator / Försök i G1A Anttila Alrik 1970 TM_REP1970/126 Konferens för anrikningstekniker. Notat från gruppdiskussioner. Se Bergstedt Lennart Use number: 1 36 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES separat volym. 1971 TM_REP1971/001 Järnoxid / Magnetisk anrikning / Rening från icke järnmetaller / 2 Bergstedt Lennart 1971 TM_REP1971/007 Kopparbly - separation / Tryckning av bly med Kromat och Dextrin VT Åberg Göran 1971 TM_REP1971/040 Garpenberg / Separation av kopparblykoncentrat Larsson Ivar 1971 TM_REP1971/098 Separation / Koppar - bly med hänsyn till zink Göransson Torbjörn 1971 TM_REP1971/125 Avslamning / Separat behandling av grovt och fint Leijon Marcus 1972 TM_REP1972/014 Flotation - Hydrometallurgi / Separation / 2 Försök med Renström Göransson Torbjörn 1972 TM_REP1972/023 Separation / Rening av lagrade koppar- respektive kopparblysliger Gräsberg Mats Boliden kemi / Reymersholmsverken / Kalciumfluorid och kiselsyra / 1972 TM_REP1972/041 Separation Gräsberg Mats 1972 TM_REP1972/063 Långsele / Reagensundersökning / Kopparblyråflotationen Göransson Torbjörn 1972 TM_REP1972/073 Avslamning / Separat hantering av grovt och fint / Anrikningsförsök Lager Thomas 1972 TM_REP1972/075 Omflotation / Separation av blyzinkkoncentrat Leijon Marcus 1972 TM_REP1972/113 Uppdelning / CuZn-separation efter värmebehandling / Delrapport 1 Törnqvist Mats 1973 TM_REP1973/003 Kopparblyseparation / Sammanställning av försök vid GF 1960-1972 Leijon Marcus 1973 TM_REP1973/014 Uppdelning / Koppar/Zink- separation på lakat kopparblyzinkkoncentrat Törnqvist Mats Uppdelning / Koppar/Bly, Zink- separation på lagrat koppar - bly - zink - 1973 TM_REP1973/034 koncentrat Sandström Eric Flotation / Jämförande laboratorieförsök på gods från A- och B- 1973 TM_REP1973/117 sektionen Sandström Eric 1974 TM_REP1974/093 Bly-zink-separation. Svaveldioxid som zinktryckare Björned Jan 1976 TM_REP1976/005 Bly / Zink- separation / Våtmekanisk blyglansanrikning Hultqvist Jan 1977 TM_REP1977/048 HGMS / Orienterande försök Borell Michael 1978 TM_REP1978/041 Anrikningsavdelningen Garpenberg - samflotation, separat volym. Hultqvist Jan

1981 TM_REP1981/064 Starkmagnetisk separation / Rening av Pb-koncentrat Borell Michael 1982 TM_REP1982/027 Halvkornsproblem vid koppar/bly- separation Uddenmalm Norén Peter Rakkejaur / Mineralteknik / Koppar/bly- separation / 1982 TM_REP1982/073 Laboratorieflotationsförsök Lundmark Fredrik 1983 TM_REP1983/037 Rakkejaur / Kopparblyseparation / Antimonrening, separat volym Lundmark Fredrik 1985 TM_REP1985/004 Kopparblyseparation / Starkmagnetisk separation. / Kostnadskalkyl Carlsson Bengt 1985 TM_REP1985/058 HGMS / CuPb-separation vid Sala International Norén Peter

Use number: 1 37 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES Bolin Nils Johan, Hokka 1985 TM_REP1985/061 Kopparblyflotation / Separation / Litteraturstudie Harri 1985 TM_REP1985/077 HGMS / CuPb-separation vid Sala International Norén Peter 1986 TM_REP1986/007 HGMS / Kopparblyseparering vid Sala International Norén Peter Projekt CuPb1 lakning av bly ur komplexa kopparkoncentrat, separat 1986 TM_REP1986/019 volym Sjöberg Kenneth 1986 TM_REP1986/021 HGMS - Kopparblykoncentrat / Fraktionsanalyser Norén Peter 1987 TM_REP1987/009 HGMS / Kopparblyseparation / Alternativa utrustningar Norén Peter 1988 TM_REP1988/051 Rakkejaur / Kopparbly och Arsenikkiskoncentrat / HGMS-försök Norén Peter 1989 TM_REP1989/001 Rockliden / Kopparblyseparation med HGMS Norén Peter 1989 TM_REP1989/041 Blykoncentrat G1A / Rening med starkmagnetseparation (HGMS) Norén Peter

1992 TM_REP1992/052 Separation av kopparblykoncentrat från Petiknäs Södra-malm Danielsson Rolf 1993 TM_REP1993/025 Kristineberg, Renström, CuPb-separation Markström Stig 1993 TM_REP1993/039 Blykoncentrat G1A/Rening med HGMS och gravimetri Norén Peter Undersökning av zinkmineral i magnetisk produkt i HGMS krets från 1996 TM_REP1996/057 G9A Pilström Göran 1998 TM_REP1998/037 Petiknäs Norra / Copper lead separation Norén Peter 1998 TM_REP1998/048 Copper-lead separation with SO2 / Evaluation of monthly results. Bolin Nils Johan RTB Bor Majdanpek / Magnetic separation of a copper-lead concentrate 1998 TM_REP1998/065 from a complex ore Bolin Nils Johan 1998 TM_REP1998/079 Copper-lead separation with depression of copper - a discussion Bolin Nils Johan

An attempt to improve the quality of lead concentrate of Petiknäs Södra 2000 TM_REP2000/065 zinc ore Johansson Anna Cleaning of the Petiknäs Pb-concentrate in magnetic field of high 2000 TM_REP2000/079 strength Johansson Björn The Renström campaign in 2001, supplementary fraction analyses in the 2002 TM_REP2002/016 CuPb circuit and final report Johansson Björn 2002 TM_REP2002/026 Kristineberg, K-ore Cu/Pb-separation test Bolin Nils-Johan 2003 TM_REP2003/064 Cu/Pb separation and cleaning of the lead concentrate Bolin Nils-Johan 2004 TM_REP2004/002 Petiknäs Södra Cu/Pb-separation with dispersion agents Bolin Nils-Johan

Use number: 1 38 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES 2005 TM_REP2005/008 Petiknäs Södra, Cu/Pb separation tests Johansson Björn Treatment of Petiknäs Pb- and CuPb-concentrates on a Slon High 2005 TM_REP2005/011 Gravity Magnetic Separator Johansson Björn Flotation investigation on scavenger concentrate and the scavenger 2005 TM_REP2005/018 concentrate from the separation circuit Wanja Dunér 2005 TM_REP2005/027 Copper-Lead separation difference for Petiknäs södra in springtime 2005 Bolin Nils-Johan 2005 TM_REP2005/030 Petiknäs Södra, Cu/Pb separation tests 2 Johansson Björn 2006 TM_REP2006/019 Depressive action of dichromate ions on galena flotation Johansson Björn 2006 Umeå University Depressive action of dichromate ions on galena flotation Jale Matlu

2011 TM_REP2012/011 Tests to replace sodium dichromate in Garpenberg Johansson Björn 2011 TM_REP2011/043 Cu/Pb separation on Renström ore without dichromate Johansson Björn 2013 TM_REP2013/039 Cu/Pb separation without Dichromate Malm Lisa Design and Development of Sulphide-Mineral Specific Collectors in Patra Anuttam, 2014 Luleå University Flotation Hanumantha Rao Kota

Use number: 1 39 Legal name of the applicant(s): Boliden Mineral AB

ANALYSIS OF ALTERNATIVES

Appendix 2: References

1 http://www.boliden.com/ 2 Klymowsky I. B., Thesis: The Role of Oxygen in Xanthate Flotation of Galena, Pyrite and Chalcopyrite, 1969, http://digitool.library.mcgill.ca/webclient/StreamGate?folder_id=0&dvs=1389960818906~111 3 Kohad V.P., Froth Flotation: Recent Trends, 1998, pp. 18-41. 4 Lowry A, Greenway H.H., Australian Patent Office # 5065, 1912. 5 http://en.wikipedia.org/wiki/Froth_flotation 6 Yarar B., Ullmann’s Encyclopaedia of Industrial Chemistry: Flotation. 7 Wark I.W., Sutherland K.L., Principles of Flotation, Aust. Inst. of Min. and Met., 1955; Gaudin A.M., Flotation, McGraw-Hill, 1957. 8 Klassen V.I., Mokrousov V.A., An Introduction to the Theory of Flotation, Butterworths, 1963. 9 Dutra, A. J. B., Espinola A., Sampaio J. O., J. Braz. Chem. Soc., 8(2), 1997, pp. 193-196. 10 Buckley A.N., Gong B., Lamb R.N., Woods R., Electrochem. Soc. Proceedings, 2000, pp. 72-83. 11 Chambers C., Holliday A.K., Modern Inorganic Chemistry, Butterworths, 1975. 12 Okada S., Majima H., Canadian Met. Quart., 10 (3), 1971, pp. 189-195. 13 Okada S., Thesis: Studies on the Depressive action of Chromate and Dichromate Salts on Galena, 1970; http://www.researchgate.net/publication/233583184_Depressive_action_of_chromate_and_dichrom ate_salts_on_galena 14 Ralston J., Min. Eng., 7 (5-6), 1994, pp. 715-735. 15 Encyclopaedia of Materials: Science and Technology pp. 1-10. 16 Baştürkcü H., Yenial U., Kökkılıç O., Yüce A.E., Erdoğan E.B., Beneficiation of Copper, Lead and Zinc Concentrates From Complex Ore By Using Environmentally Friendly Reagents: http://www.arber.com.tr/imps2012.org/proceedingsebook/Abstract/absfilAbstractSubmissionFullCo ntent338.pdf 17 http://www.lovisagruvan.se/produktion/produktioninfo 18 Bulatovic S.M., Handbook of Flotation Reagents: Chemistry, Theory and Practice, Elsevier Publishing, 2007, pp. 379-400. 19 Internal Boliden Report: TM_REP2012/011, 2013. 20 Pearce C.I., Pattrick R.A.D., Vaughan D.J., Reviews in Mineralogy & Geochemistry, 61, 2006, pp. 127-180. 21 Kindig J., Turner R., Patent PCT/US1979/000475, 1979.

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ANALYSIS OF ALTERNATIVES

22 Wu W., Wu C., Hong P.K.A., Lin C., Environmental Technology, 32 (13), 2011, pp. 1427-1433. 23 Svaboda J., Guest R.N., Venter W.J.C., J. S. Afr. Inst. Min. Metall., 88(1), 1988, pp. 9-19. 24 Internal Boliden Report: TM_REP1985/058, 1985. 25 Internal Boliden Report: TM_Rep 1973-003, 1973. 26 Internal Boliden Report: TM_Rep 1998-037, 1998. 27 (a) Liu Q., Laskowski J.S., Int. J. Miner. Process, 27(2), 1989, pp. 147-155; (b) Bhaskar R.G., Holmgren A., Forsling W., J. Colloid Interface Sci., 193, 1997, pp. 215-222; (c) Liu Q., Zhang Y.H., Int. J. Miner. Eng. 13(13), 2000, pp. 1405-1416; (d) Lopez V.A., Celedon C.T., Song S., Cabrera A.R., Laskowski J.S., Int. J. Miner. Process., 17, 2004, pp. 1001-1006; (e) Wenqing Q., Qian W., Fen J., Congren Y., Ruizeng L., Peipei W., Lifang K., Int. J. Mining Sci. Tech., 23, 2013, pp. 179-186; and references contained therein. 28 Drzymala J., Kapusniak J., Tomasik P., Int. J. Miner. Process., 70, 2003, pp. 147-155.

Use number: 1 41 Legal name of the applicant(s): Boliden Mineral AB