Nº 90, June 2014

The OHL Group Magazine

tecnoNº 90, June 2014

The Královo Pole tunnels, the key to improve traffic in Brno

Terminal de Contenedores de Tenerife, a reference logistics platform in the Atlantic

Design and construction of a copper treatment plant in Chile

1 4 The Královo Pole tunnels, the key to improve traffic in Brno

Terminal de Contenedores de Tenerife, a reference logistics 14 platform in the Atlantic

24 Design and construction of a copper treatment plant in Chile

tecno Revista del Grupo OHL Staff

Editor: General Corporate Management. Coordinator: Communications and Image Service: Mar Santos ([email protected]), Marisa Gutiérrez Sánchez ([email protected]) and Lourdes Peiró ([email protected]). Collaborator: José María Sánchez Moreno ([email protected]). Edited by: Tomáš Just, José Ignacio Uriarte, Diego Sánchez and Jesús García Florén. Traslation: IBERTRAD OHL need not necessarily share the opinions given in this Magazine. Reproduction prohibited. All rights reserved/Tecno. Paseo de la Castellana, 259 - D. Torre Espacio - 28046 Madrid. Design, layout and production: Eventos y Sinergias, SL Legal deposit: M-31540-1991.

2 Editorial

The OHL Group, which consolidated its presence in the Czech Republic more than ten years ago through its OHL ZS subsidiary, has executed the Královo Pole Tunnels in Brno. Construction of this infrastructure has involved, for the first time in this country, mining tunnelling methods, and the site is located to the north and northeast of the third ring road (VMO), as part of the city’s basic transportation system and road network in the Czech Republic.

In Spain, OHL Concesiones holds a majority 65 % stake in the concessionaire Terminal de Contenedores de Tenerife S.A., (TCT). This logistics platform, used for import, export and transfer, is a reference in the Atlantic. It has a mooring line 700 metres (m) long, more than 16 m deep, and a surface area of 15 hectares. Its facilities and equipment, with operating capacity of 620,000 TEUs/year, are designed to service the most modern vessels.

To end this issue, we would like to refer to the copper mineral treatment plant executed by OHL Industrial for Corporación Nacional del Cobre de Chile, Codelco. It includes the design, execution, exploitation, operation and maintenance, over a 36-month term, of an EPC (Engineering, Procurement & Construction) project: Integral grinding service, acid curing and on-site piling of oxides in the Ministro Hales mine, a field located 5 kilometres north of the city of Calama, in the Second Region of Antofagasta. The installation, with production capacity of more than 7,200,000 tons/year, offers a new semi-continuous piling system.

Luis García-Linares General Corporate Manager

3 4

Interior of one of the tunnels of Královo Pole in Brno, Czech Republic. The tunnel was built using the mined tunnel excavation method, the first time this method was used in the Czech Republic

The Královo Pole tunnels, the key to improve traffic in Brno

The Královo Pole tunnels are located in the north and north- west sections of Brno’s third beltway (VMO) and are key elements in the city’s basic transportation system, as well as the highway network of the Czech Republic. The tunnels carry up to 25,000 vehicles every day and at rush hour, re- lieving traffic congestion in the city. In addition, once the VMO has been fully completed, the connections between internal and external traffic will be resolved, significantly improving traffic flow on the city’s internal roads.

The project VMO Dobrovského B was executed in the city of Brno, in the area near the Žabovřesky and Královo Pole neighborhoods, which are densely populated and have an extensive network of underground services, as well as surface roads and sidewalks. The work mainly included the construction of two parallel tunnels, each with two lanes, and the Žabovřeská-Hradecká and Hradecká- Královopolská interchanges in the Žabovřesky neighborhood, and part of the Dobrovského-Svitavská radiála access

Interior of one of the tunnels of Královo Pole in Brno, Czech Republic. Brno Beltway, with roads in the Královo Pole neighborhood. Principal characteristics connections to the The Technology Center (TC) for the tunnels highway network. is located between Dobrovského and To undertake the work, the mined tunnel ex- Slovinská streets. cavation method was used for the first time, with a specific excavation distribution and support provided The monitoring of the impact generated by the by shotcrete rein- tunnel that was included in the project was forced by Hebres metal supports de- the most extensive applied in the Czech Republic signed and fabri- to that point cated specifically for the project. The project included the most extensive monitoring of the impact generated by the tunnel excavation ever carried out in the Czech Re- public up to that point. The Královo Pole tunnel consists of two tubes:

lTunnel I. This tunnel runs along the line of the Dobrovského and Veleslavínova streets and is 1,239 meters (m) long.

lTunnel II: Part of the line follows Pešinova street. It is 1,261 m long and runs parallel to tube I. The maximum separation of the centerlines of the two tubes is 93 m. Both tunnels Diagram of a BRETEX truss (BTX), which combines BTX and HEB profiles. were designed for a single direction, but

6 allow traffic in both directions in case of emergency. The standard cross-section for traffic consists of an open width of 8.50 m between curbs, and two emergency sidewalks at least 1.15 m wide on both sides of the tube. The tunnel lining, including the floor is made up of reinforced concrete. A false ceiling was installed along almost the entire length of the tunnel to separate the traffic area from the ventilation duct (VZT) and was designed for the removal of smoke and contaminated air in case of fire or emergency. The roads and sidewalks are made of concrete, with the exception of the sections near the tunnel openings and on the surfaces of the roads entering and exiting, which are made of asphalt mix. Concreted plastic SITEL conduits were installed under the sidewalks, supplemented in some sections with corrugated tubes to protect cables. Inspection boxes are one-piece, with covers made of different materials, and the conduits that run under the sidewalks are connected by cable protection tubes that are run under the roadway and in the tunnel lining. Both tunnels have low-voltage (LV) distribu- Main fans located in the tion boards with 400/230 volt (V) connec- technology center above the tunnels. tions for installations and/or maintenance, Fire protection located in each SOS cabinet. Also, the VZT conduits that run above the false ceiling are systems equipped with lighting and 230V electrical outlets next to each intake valve. A DN 200 fire-protection system was installed There are four connection galleries (with in the tunnels. This is a closed water-fed circuit, fans) between the two tunnels for evacua- with hose connections located in openings in- tion situations, separated from the tunnels tegrated into the tunnel lining. Each tunnel has by a fire wall with a fire damper in order to twelve hose connections and water and other keep the gallery pressure higher than the liquids on the roadway are collected through pressure in the affected tunnel. The gallery slotted curbstones along the length of A DN 200 fire-protection system was installed in the the tunnels. In order to prevent tunnels. This is a closed water-fed circuit with hose the propagation of fires caused by flam- connections located in openings integrated into the mable liquids catch- tunnel lining drains were installed 50 meters apart. The conduits discharge to floors are equipped with multiple collectors liquid-collection tanks located at the low to hold the cables that connect the cables point of the tunnel, and each tank is equip- run along both tubes, with a total of three ped with two automatic pumps that drain the large electrical niches with distribution contents to the Ponávka II collector. boards.

7 Excavation work.

Žabovřesky opening were used in the construction and the floor (west tunnel opening) of the opening is anchored at the sidewalls of the tunnel. The roof, including the cornice, was made with a continuous is anchored at Located in the Žabovřesky neighborhood, thereinforced-concrete slab anchored at the this opening was designed as a reinforced- top of the Milan walls. concrete framework structure. Milan walls The length of the opening at the tunnel centerline is 18 m. The Žabovřesky cut-and- cover tunnel connects to the permanent opening of the Two technology buildings are located above the tunnel. The ceilings of both tunnel roof and provide access to the VZT duct tubes have aerodynamic openings with four jet fans 1.40 m in diameter. They also share the VZT duct located above the false ceiling. It has a closed rectangular reinforced concrete structure with pressure-resistant sealed sheets used for waterproofing and in the duct. There are two technology buildings located above the tunnel roof that provide access to the VZT duct. Both buildings are one- piece structures that are partially integrated into the retaining walls. These house the low-voltage switchboards for the technology installations and the indoor facilities are equipped with heating and ventilation. Excavation method.

8 Two reinforced-concrete ramps were constructed at the tunnel exit to connect to Žabovřeská street. These ramps are 203 and 237 m long with a minimum width and height of 9.20 m and 5.25 m. The technology buildings are not directly connected to the tunnel, but rather are used in the organization and management of the tunnel traffic.

Královo Pole opening (east opening)

Located in the Královo Pole neighborhood, it is equipped with an aerodynamic opening with four jet fans 1.40 m in diameter. The structure of the cut and cover tunnels is similar to that of the Žabovřesky infrastructure –closed rectangular reinforced concrete structure waterproofed with sealed pressure-resistant sheets–. Independent technology buildings are located above the roofs of the tubes and are equipped with distribution boards for the tunnel’s technology equipment. The covers on the floor of each one of the buildings provide access to the VZT duct that runs above the false ceiling. The last Královo Pole opening serves both tubes, with a one-piece reinforced concrete frame connected to the reinforced concrete tunnel invert to offset the underpressure, and to retaining walls.

Tunnel construction

The following measures were adopted in order to minimize the risks and reduce the impact on the urban development on the surface: the volume of material excavated and used View of the inside of one of the tunnels. l Excavation work aimed at enlarging the to construct an access ramp to the invert. edge of the crown of the tunnel invert in or- l The number of pile walls constructed along der to increase stiffness/solidity. the length of Dobrovského street, which sup- l Reinforcement of the shotcrete support ported practically all of the buildings on the using welded Hebrex reinforcing elements, street, has been completed. designed by the project designer as an alter- l Supplementary injection to support 26 mul- native to metal HEB trusses. ti-story buildings with the most significant l Adjustment of the step length of excava- susceptibility to impact by the excavation. tion fronts. These were shortened as much This was the first time that this technology as possible, multiplying, several times over, was used in the Czech Republic.

9 Connection of tube II Excavation method Ground settlement, with the subsidence of with the ventilation surface buildings and the deformation of shaft. The waterproof sheet For the first time in the Czech Republic, an services, especially pipes, was taken into and the tunnel lining excavation method divided both horizonta- account while this work was being carried structure are visible in lly and vertically was used. The total cross- out. In this regard, the average settlement the front. section of 130 square meters (m2), was exca- measured during the excavation of explo- The concreting machinery is in the vated successively on six partial workfaces ratory galleries reached 58 millimeters back and the workface with areas ranging from 14 to 25 m2. Excava- (mm), with other settlement values expec- with formwork removed. tion advanced in steps one meter deep that ted to be between 200 and 250 mm. were sealed immediately. This provisional Constant observation was maintained for support was then demolished when a new previously reinforced buildings and services front was opened. and the buildings that were most susceptible to impact –a total of 110– For the first time in the Czech Republic, an were reinforced using micropile screen walls and excavation method divided both horizontally compensation grouting. and vertically was used In specific cases, it was necessary to supplement The selected method did not allow heavy the previously executed screens. machinery to be used. Smaller, less powerful Prior to the excavation, pipe networks and machines were used instead. The excavation household service connections and connec- was executed in one meter steps and the tions to distribution lines of the public net- tunnel invert was excavated in four-meter work that were found to be deteriorated or de- steps. The average speed for the excavation fective were repaired using flexible materials. of the entire profile was 42 meters a month. Also, despite its age, the sewer network conti-

10 nued to operate with no problems during the remove the pollutants generated by the traffic. work and no malfunctions were detected in The space above the false ceiling is accessed the gas distribution pipelines or power lines. through covers measuring 900/900 mm that are installed in the false ceiling next to each one of the trapdoors. Mined tunnel excavation Both tubes are connected to the technology center (TC). Tunnel I passes directly through The cross-section of the two mined tubes is the underground part of the technology the same and is constant. The support is at center. It is connected to the emergency least 350 mm thick at the bottom part that gallery located in the TC building, which is supported on the floor. Sealed pressure- has two escape openings: one, a gallery resistant sheets were used to waterproof the that connects to tunnel II, and the other the tubes. emergency stairs that lead to the surface. The open cross-section of the tunnel is divi- The TC is also equipped with an evacuation ded into two parts: elevator. The escape gallery provides access 2 l The traffic section, with an area of 58 m . to several technical installations located

l The section for the VZT duct, which covers on the seventh floor of the underground 2 11.50 m . part of the TC. The rest of the technological The two spaces are separated by a false installations are not accessible from tunnel ceiling made up of a concrete slab 250 mm I. The part of the VZT duct that runs through thick. Trapdoors were installed in the slab the technology center is connected to the every 80 meters to remove heat and smoke in ventilation rooms, which are equipped with case of fire. These trapdoors are also used to axial fans.

Access and exit of the Královo Pole tunnels. Technology Center (TC) shored up by Milan walls. The underground part was waterproofed completely using This is a building with seven underground sheets connected to the tunnel sheets. floors and one floor above ground. The The building is fenced and protected by above-ground part consists of the elevator an electronic security system and video exit, the emergency stairs, and two stacks surveillance cameras. that extend approximately 26 m above the surface. The building and stacks are made of reinforced concrete. Ground conditions The signs for one Work and assembly platforms were ins- of the emergency exits talled between the two stacks, providing The geological conditions of the tunnel are visible on the left, with a SOS post on the access to the inside of the stacks to allow are relatively uniform. The thickness of right. inspections. loess (aeolian sedimentary geological

Tunnel control center located in the Brnênské komunikace office.

The antennas for the wireless communica- material) and anthropogenic layers ran- tions and mobile telephony were then insta- ges between three and ten meters. Sand lled on top of these. terraces and gravel aquifers are located below. The underlying la- The underground part of the TC is a one-piece yers are made up of neogenic clay (belonging to reinforced-concrete structure that was poured the period at the end of in situ in a shaft shored up by Milan walls the Tertiary, which includes the Miocene and Plio- The underground part of the TC is a one-piece cene periods) which are several dozens structure that was poured in situ in a shaft of meters thick. No rock was encountered

12 Tunnel control center located in the Brnênské komunikace office.

in boreholes drilled to depths of up to 60 meters. The underground water retained by permeable gravel is found at the level of the late neogenic horizon in the form of perched water tables in local depressions. The predominant consistency of the neogenic clays is solid, with a high degree of plasticity. These clays, when mixed with underground water under certain conditions, have a high pressure coefficient. Both tunnels pass through neogenic clay. The coverage of both tubes is almost iden- tical, with the thickness ranging from 6 to 21 meters. The tunnel layout respected the condition of leaving an impermeable layer of two or three meters of clay above the excavation at all times. Longitudinal cross-section of the Královo Pole tunnels.

Article author: Tomáš Just, production expert in the OHL ŽS office in the Czech Republic Photos: Jiří Oság and Josef Tetur, archive of OHL ŽS, publication Královopolský Tunnel, Brno

13 With an operating capacity of 620,000 TEUs per year, the terminal is designed to provide service the new generation of ships

Terminal de Contenedores de Tenerife, a reference logistics platform in the Atlantic

Aimed at import, export and transhipment traffic, the Terminal de Contenedores de Tenerife (TCT), a concession company of OHL Concesiones, has a 700 meter (m) berthing line with drafts up to 16 m, and covers an area of 15 hectares (ha). Its facilities and equipment have an operating capacity of 620,000 TEUs (twenty-foot equivalent units) per year and are designed to provide service the newest generation of ships, making it a reference logistics platform in the western arc of the coast of the African continent at this time.

Terminal de Contenedores de Tenerife, S.A. potential as one of the leading ports on the (TCT) is the company that is responsible for Atlantic. the development of the construction and The concession, led by OHL Concesiones operation project of the public container with a 65% stake in the concession terminal on the East Dock of the Port company, has a term of 30 years, a total of Santa Cruz de Tenerife (Spain). The investment commitment of 64 million concession for the new container terminal euros, and has carried out the actions was awarded in 2012 by the Port Authority defined in its investment plan in optimum and forms part of the Container Terminal conditions to complete the final details of Reorganization Project, giving the Port of the terminal and start operations in the Santa Cruz de Tenerife the infrastructure first half of 2013. and conditions that it needs to develop its

14 Phase one of the project connect up to 528 refrigerated containers Port operations in (reefers), 12,000 m2 of access and control the Terminal de Contenedores de TCT completed phase one of the investment roads, and an adjacent area for operations Tenerife. Spain. in its terminal in 2013. The machinery covering 35,000 m2 and 6,000 m2 for installed includes three ZMPC super post parking and offices, respectively. panamax cranes, with an ocean-side reach The investment program that was carried of 61 m; five RTG Paceco cranes; three reach out also added significant operational stacker cranes (Hyster); 12 tractors and 12 improvements: platforms (pallet wide). l Roll on/Roll off (Ro-Ro) Ramp.

Thus far, a maintenance and storage area l Capacity for more than 528 operational of 52,000 square meters (m2) has been refrigerated containers, with the possibility put into operation, including walkways to of expanding to 750 plugs.

15 l Remote control of refrigerated units. refrigerated containers (reefer monitoring)

l Automatic access for land container will be put into operation. receiving and delivery.

l Automatic positioning of containers in yard for unloaded and incoming units. TCT Equipment The installation also includes a computer system and fiber-optic and wifi networks The first challenge that was successfully that allow GPS (Global Positioning overcome was the selection and acquisition System) positioning of containers in real of the machinery required for the port time, automatic access control using operations in record time. To do this, for cameras and OCR (optical character the first time, the three super post Panamax recognition) units that automatically cranes were transported using a pontoon record photographs of the containers upon and towing system. arrival and departure by both land and sea, In August 2012, the purchase of the aforementioned cranes The installation includes a computer system and was finalized with the Port of Amsterdam. fiber-optic and wifi networks that allow containers to The cranes are 74 m be positioned using GPS high, weigh 1,500 tons, and are equipped with booms with a 61 m and management of prior notifications by ocean-side reach, which made the process for clients via the web. reinforcing and preparing to move a difficult and In 2014, the Terminal de Contenedores de delicate task. Tenerife will complete the commissioning In November of 2012, after a month at sea, of the storage area, reaching a total of TCT received the cranes fully assembled, 150,000 m2; also, a sixth RTG (transtainer) which sped up the process of commissioning will be received and a system for tracking them on the docks.

Developing the port’s potential

The characteristics of the Terminal de Con- tenedores de Tenerife and its strategic location allow it to handle international transhipment container traffic to and from Europe and the Americas, and from these countries to the emerging markets on the Atlantic coast of Africa, in addition to handling the growing demand of local traffic.

16 Ro-ro Ramp occupy the water sheet or that reduce the Preparation and available berthing in other port alignments reinforcing of cranes in Amsterdam, shipping, The increase in Roll-on/Roll-off (Ro-Ro) traffic was impossible. To overcome this, an and arrival at Tenerife. in recent years for the loading and unloading innovative retractable ramp was designed of vehicles requires ports to be equipped and built for Ro-Ro traffic. This ramp is with adequate facilities to handle the hinged at its connection to the dock and is demand for this type of port traffic in order larger than the ramps built up to this point to make their operations more competitive. (20x25 m), weighing 100 tons and with a In order to be able to receive ships that transport service load of 180 tons. wheeled cargo –in the specific case of TCT, Innovative hinged ramp for Ro-Ro traffic, containers mounted measuring 20 by 25 meters and with a service on semi-trailers and tractor units– the load of 180 tons construction of a Ro-Ro ramp was planned at the north end of The ramp is secured to the dock by two steel the east breakwater, which would be able portals that transmit load to the foundation, to be used for the execution of this type of reducing the bending moments, and operations, as well as Ro-Lo type operations, replacing them with a system of forces. which is a mixture between a Ro-Ro ship and a In the southern portal, the rear footer acts container ship. as a counterweight to withstand the upward Due to the environmental limitations, the vertical force of 4,980 kilonewtons (kN). It is installation of conventional models that also subjected to a horizontal load directed

17 Ro-ro Ramp.

Hinged Ro-Ro ramp towards the dock of 2,540 kN, which is optimize costs in comparison with other at the Terminal absorbed by a bracing beam 4 m wide and solutions available on the market, such de Contenedores de Tenerife. 0.25 m thick. as floating ramps, and reduces the time Although the capping beam is subjected required to deploy and remove the ramps to to horizontal loads that are transmitted by 15 minutes. the hinges (thrust towards the dock) and the portals (pulling towards the quay), the overall resulting horizontal force is zero. Adaptation of articulated An imbalance of approximately 300 kN directed towards the back wall is generated flipper for RTG and Reach by the south hinge-south portal combination. Stacker In the north portal, the foundation was constructed by demolishing part of the The system for securing containers for handling underwater concrete block and part of the is based on the standardization of the dimen- first reinforced concrete caisson in the sions and the locations of the anchor points alignment. of the machines that handle them with an attachment called a spreader. These Development of a mechanically-activated articulated points are made flipper that improves efficiency in loading and up of four corner fittings into which unloading operations the four twistlocks of the spreader fit, This solution replicates the ramp on the and which, once they are locked, allow the con- stern of a ship and makes it possible to tainer to be lifted.

18 Ro-ro Ramp.

To facilitate this task for the operator, the standard spreader is equipped with an end stop known as a flipper at the end, which is supported on the side of the container, so that the twistlocks can be easily aligned to face each other to fit into the corner piece. There are also containers with non-standard measurements that shift the twistlock housing with respect to the side of the container, making it impossible to handle it and requiring dockworking companies to set aside space and specific machinery to handle them. In addition to this loss of space and efficiency in loading and unloading operations, this machinery is not equipped with flippers or stops, affecting operational performance, which is directly proportional to the skill of the handler. To offer a more efficient solution for the handling of this type of containers, a two- piece mechanically-driven articulated flipper was developed, with one fixed piece on the spreader and a movable piece that is RTG Spreader. articulated on the fixed piece, which, by

19 applying force by two springs, can adapt arrive at the terminal without having received to containers with standard widths, as well a single piece of paper. as those with dimensions that exceed the standard values. Automation of the arrival and departure of containers Management and control and positioning by system for shipping GPS/RFID companies and trucks Thanks to the implementation of all of the The management and control system for elements that form part of the project, the shipping companies and trucks was one of movement of containers in the terminal has the first projects undertaken at the start of been automated in all phases: arrival of the operations. In order to offer transparent trucks, crane operations, and departure of trucks. Thanks to the implementation of all of the elements, To achieve these proposed objectives, the movement of containers in the terminal in all the incoming flow phases has been automated of trucks has been configured to adapt it computerized service, the work system of to the geometric conditions of the terminal; the local transport companies and their all of the truck traffic enters through a single connection with the shipping companies gate equipped with an automatic scale and Web access for truck drivers via mobile was studied. Based on the results obtained, an arch that identifies the vehicle by its RFID phone. TCT identified tools –website, automatic tag (radio-frequency identification), reads

file processing, automatic mail programs– that made it possible to replace the paper flow with computerized systems that were transparent to drivers. At this point, drivers

Scale and OCR arch at the entrance. the license plate and container number, and shipping company has provided through the Access control system. automatically feeds the system, integrating electronic data interchange (EDI) website. the data and work commands that the This means that container entry is processed without any human intervention, while at the same time recording high-resolution images and videos for damage tracking. The identification of the truck from the moment it enters the terminal allows commands to be sent from the system to the machines that will proceed to unload and load the trucks. The trucks are weighed again at the terminal exit, identified, and photographed, which prevents incorrect delivery of containers and allows images related to the condition of the containers upon arrival, and later when they leave the terminal to be kept on record. A similar process is followed during the container loading and unloading operations. During the crane operations in the terminal, trucks are identified by RFID tags to prevent errors in the truck/container assignment. The positioning of the cranes using DGPS (Differential Global Positioning System), integrated by computer into the operation of the machine, ensures the correct position of the containers in the terminal. One hundred percent of the containers are photographed, and the storage orders are generated and updated automatically.

Scale and OCR arch at the entrance. TOS (Terminal Operation System). Map of the terminal with the location of containers and machines.

ReachStacker crane.

22 Super Post Panamax crane.

The level of overall automation attained in TCT has significantly reduced operating costs, increased the functional efficiency of the terminal and the transport companies, and has reduced complaints and expenses generated by mistakes in the delivery and loading of containers and damages that do not occur inside the terminal. The management of containers with hazardous goods has also been improved and they are now identified and tracked perfectly at all times. This automation has significantly reduced the time that trucks remain in the terminal: the crane receives the number of the container that it has to deliver to a particular truck ahead of time, along with the container RTG crane. movements required to access it.

Authors: José Ignacio Uriarte, General Manager and Diego Sánchez, Director of Operations

23 General overview of the plant.

For the first time, OHL Industrial has developed and applied an innovative semi-continuous stacking system

With a production capacity of 20,000 Design and construction of tonnes (t) per day and more than 7,200,000 t per year the plant execution a copper treatment plant project to crush mineral to obtain copper using acid curing includes the activities in Chile required to transport the mineral from a stock of oxides in situ (OIS), crushing, the sampling of operational variables for the process, the curing of the mineral over the transport system and their final For the Corporación Nacional del Cobre de Chile, Codelco, deposit in leaching piles. OHL Industrial carried out the design, execution, exploitation, To meet these objectives OHL Industrial operation and maintenance for 36 months of the EPC project has developed the conceptual, basic (Engineering, Procurement and Construction) Integral service and detailed engineering, executing of crushing, acid curing and stacking of oxides in situ in the the manufacture, supply, construction Ministro Hales mine, a site located 5 kilometres (km) to the and assembly of all the equipment and north of the city of Calama, in the Second Region of Antofagasta facilities required for the plant and has (Chile). The project, integrated in the Ministro Hales Division, commissioned it to proceed with its the most recent of Codelco, will include an innovative semi- operation and maintenance for 36 months, continuous stacking system. the phase it is currently undergoing.

24 General overview of the plant.

Process for obtaining copper

In situ leaching is a hydrometallurgical process to extract copper by dissolving it in sulphuric acid. To this end the ground has to be prepared by flattening the surface for stacking and subsequent waterproofing. Likewise there is a mineral treatment plant to reduce it to the required size (that which allows the maximum permeability), and large earth moving machines for the product to facilitate the transport and construction of the piles, as well as the removal of the waste produced.

As part of the design of the large leaching yard there is piping to take the sulphuric acid to a recollection pool. Likewise, there are transportable plastic conduits and sprinklers which move from one pile to another. The complement, as in the previous case, is comprised of small pumping stations.

The electro-recovery of the copper is performed through the electrolytic deposition of cooper based on rich leaching dissolutions and consists in reducing the metal over cathodic sheets and with inert anodes. The cathodic reaction is the same as the elec- trolyte refining which makes the copper stick to the cathodes.

The acid formed is returned to the leaching or to the extraction circuit. The anodes are insoluble and anode sludge is not formed. They are normally manufactured in alloyed lead although they can be done in plated titanium since they reduce the oxygen potential which allows reducing the potential for the reaction of gaseous formation and increasing the current performance by 90%. Moreover, they avoid cathodic contamination as the result of dragging lead particles.

25 Mineral processing material from the stock of mineral provided by Codelco. The crushers pour the mine- The plant is basically comprised of different ral on mobile Sthim belts (OHL Industrial areas intended for primary, secondary and trademark) referred to as grasshoppers, to tertiary crushing with preselection of mate- supply a regulation hopper with a capacity of rial, sampling and its analysis, acid curing on 120 cubic metres (m3). Each belt has a capa- a conveyor belt and stacking. This process is city of 1,500 t/hour to guarantee the entire divided into the following phases: production with the one transport line. 1. General overview of the equipment. Loading of material and primary crushing. Secondary and tertiary crushing. The afo- 2. General overview The loading is performed by direct loa- rementioned hopper with a capacity of of the operation. 3 3. View of the stacker ding from the mineral stockpile run of mine 120 m regulates and distributes the flow of and bridge belt. (ROM) to the primary mobile crushers. The- material to the two secondary and tertiary 4. Position of the re are two mobile lines with a capacity of crushing lines vibrating hoppers. Each line, conveyor extended by 4 m and arm 750 tonnes per hour (t/h), comprised of jaw with a capacity of 750 t/h, is comprised of to the right. crushers, supplied by hoppers, taking the a material preselection screen, secondary

1 GRASSHOPPER TO BRIDGE GRASSHOPPERS

BRIDGE BELT

STACKER

TRIPPER

3 4

26 5 6

7 8

crusher and two tertiary crushers. This set Transport of material. Once the crushing 5. Position of the is rounded off with other final material se- phase has been completed the resulting pro- conveyor extended 4 m and arm to the lection screens. duct with a flow rate of 1,500 t/h and with a left. The product is transported from the 120 m3 granulometry of less than one inch is trans- 6. Position of the hopper using a conveyor belt up to another ferred using Sthim conveyor belts up to the conveyor extended 3 2 m and arm to the regulation hopper with a capacity of 60 m , sampling tower before which there is a con- left. which supplies a first material separation tinuous weighing system. On an hourly basis 7. Position of the screen. This screen classifies the metal to in this tower the granulometry and the mine- conveyor extended be treated by the secondary crusher and ral composition are analysed. by 0 m and arm to the right. the other which has to be sent directly to The material is transported by an overland 8. Bridge belt at 30 m. the tertiary crusher. conveyor measuring 800 metres, designed 9. Displacement of The product resulting from the secondary especially by Sthim, up to the stacking area. grasshopper and start of sequence. phase is taken by conveyor belt to the se- The aforementioned conveyor has a trip- cond 60 m3 hopper at the outlet of which per to extract mineral to the stacking area. there are two screens whose function is to Within the actual conveyor the material is classify the final material and the return to supplied with the water required for curing the tertiary crusher. With this closed mine- with sulphuric acid. ral circuit intended for crushing, better use is achieved of equipment whilst also mini- Curing. Acid curing is performed on a mising the capacity required in equipment. grasshopper conveyor belt in two phases

27 during which use is made of two conveyors for adding acid and a reserve conveyor. This ensures guaranteeing a greater mix of acid with the mineral in the transfers of the conveyors.

Stacking. The material is transported, using various grasshoppers, to a mobile tilted conveyor which takes the material up to a bridge conveyor which supplies the radial stacker. This set of equipment, designed and customised for this project represents a semi-continuous stacking system with a continuous stacking capacity of stacks measuring 25 metres wide by 36 m long by 8 m high, where it is only necessary to reposi- tion a grasshopper to continue stacking. During the first 36 months of operation it is planned to process 22,400,000 t of material, for which there will be four floors of material with a height of 8 m to complete the 32 m of Detail of the tertiary screen. processed material.

Conveyor belt in the crushing plant.

28 Loading of material Crushing and (Run of mine ROM) screening Transport Acid curing Stacking

Applied innovation Competitive Phases of the project. advantages The Technical Department at OHL Industrial of the innovation specialised in mining and cement has been responsible for the design of an innovative The main advantage of this stacking sys- stacking system based on two stackers de- tem is the partial elimination of downtime signed over metal pontoons supplied to the when moving the stacker and the bridge slag and gypsum parks of Endesa, in Car- belt since these, during the manoeuvre, boneras (Almería) and Compostilla (León), can continue to pour material which distin- respectively, both located in Spain. guishes them from other available systems The aforementioned system is comprised on the market. of a conveyor belt with a tripper with pneumatic The stacking system is comprised of a conveyor wheels able to be located at any longitudinal belt with a tripper with pneumatic wheels able point of the stacks. The- se also have the con- to be located at any longitudinal point of the veyor belts on wheels stacks referred to as grasshoppers, located on the line up to the stacking The time used to perform the retracta- machines. ble stacking operation is 1.5 hours. Each The stacking start-up and stopping se- operation requires six operations to re- quences and commands from the offloa- position the stacker and the bridge belt. ding belt of the tripper up to the telescopic With a discontinuous system this would stacker are performed manually and semi- mean six stops of the facility of a mini- automatically and to activate the start-up mum of three minutes each. It is estima- the line equipment must be positioned ted that over the three years of operation and connected. The start-up sequence is of the facility 10,000 operations would as follows: be saved which means 21 complete days l Telescopic stacker of work. l Bridge belt l Grasshopper to bridge l Grasshoppers l Tripper offload belt l Tripper belt

29 Commitment Interconectado del Norte Grande (SING) to the environment (Great North Power Grid) as a reference of 0.51 tonnes per MWh). and local communities Likewise the facility has acid spillage contention systems with safety conduits The stacking system entails a reduction in with geomembranes throughout the acid exploitation time and an energy saving of line and systems of the pipeline connections 527 megawatts per hour (MWh) with regard with dry connections. to the traditional system. Its use also means There is a dust removal system by pulveri- sation and dry mist The facility has acid spillage contention systems at the dust emission points which gua- with safety conduits with geomembranes through- rantees, as a mini- out the acid line mum, 90% control of emissions. Mo- the reduction of gases originating from the reover, all the belts, hoppers, crushers machinery and the mobile park estimated and screens have been encapsulated to to be 269 t (taking the values of the Sistema prevent leaks.

Line Grasshopper system.

30 In relation with the development of local 150 are local and more than 160 training Detail of the stacker and communities, more than 350 direct and hours have been carried out for workers at bridge belt. indirect jobs have been created of which the facility.

Author: Jesús García Florén, Technical Director of OHL Industrial (Mining and Cement)

31 OBRASCÓN HUARTE LAIN, S.A. Paseo de la Castellana, 259 - D - Torre Espacio 28046 - MADRID Telephone 91 348 41 00 - Fax 91 348 44 63 www.ohl.es WORKS THAT MAKE HISTORY

Hydrocarbons storage terminal. Algeciras. Spain.