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Mine Waste Management Draft-Apr 11th 2013

ARCADIS is an international company providing consultancy, engineering and management services in infrastructure, environment, water and buildings, to enhance mobility, sustainability and quality of life.

ARCADIS develops, designs, implements, maintains and operates projects for companies and governments.

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Where is ARCADIS? A global network based on strong local positions

Health & Safety Vision As a socially responsible company, and through alignment of H&S with our other core values of Integrity, Entrepreneurship and Agility, ARCADIS is committed to being one of the safest and most healthful companies in our industry. Our commitment to prevent injuries and illnesses benefits our employees, clients, partners and all other stakeholders as we strive for zero incidents in everything we do.

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We value health and safety as much as our other core values and make it an integral part of the solutions we provide to our clients.

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more than

700

Employees in Chile & Peru

Member of Program

World Class Route BHP Escondida

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Mining Services ARCADIS provides comprehensive mining services, from exploration and mine planning to process design and operation to closure. We offer an in depth understanding of the mining industry with: • Sustainable development practices built into our

mining services to improve your triple bottom line - financial success, environmental protection, and corporate social responsibility.

• Proven innovative mining technologies that minimize costs and maximize profits.

• Cost-effective solutions focused on reducing risk and improving our client’s mining results.

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What do we do?

• Site evaluation and

selection studies

• Strategic risk analysis and follow up

• Economic analysis

• Sustainability analysis

• Mine Life cycle planning

• Environmental baselines studies

• Environmental and socio economic impact assessment

• Permitting and regulatory compliance

• Due diligence

• Scoping to detailed

engineering studies

• Facilities design

• Process design

• Environmental studies

• Trade off studies

• Project planning & scheduling

• Cost estimating

• Geological, geotechnical geomechanical, hydrology, hydrogeology rheological, hydraulics and geochemical studies

• Metallurgical studies

• Construction

supervision and Inspections

• QA/QC

• Project Management (PM)

• Construction Management (CM)

• Engineering, Construction, Procurement & Management (EPCM)

• Procurement

• Bidding process support

• Commissioning and start-up

• Operation planning

• Optimization

• Auditing

• Reprocessing

• Regulatory compliance

• Operation and maintenance manuals

• Training courses for plant operators

• Instrumentation & monitoring

• Ore processing operation/ optimization

• Mine Closure planning

• Engineering for mine closure

• Economical assessment and guarantees

• Post closure analysis

• Monitoring & follow up

• Natural resource damage assessments

• Mine waste treatment technology

• Water and solution

balance modeling

• Water recovery improvement

• Strategic water management and design

• ARD Management

• Effluent treatment plants design

• Solutions processing

• Water efficiency

• Water treatment, storage and conveyance

• Water diversion works

Design (Brown or green field)

Strategic Analysis Construction Operation Closure &

Remediation Water

Management

Project Lifetime

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Mine Waste Management Package ARCADIS Chile offers an in depth understanding and an integrated vision of the management of mine wastes:

• Solutions for all the life cycle of mine projects, from strategic analysis and environmental studies to mine closure

• Effluent treatment, tailings storage facilities, waste rock deposits and leaching tails

• Water management

• Cost-efficient and sustainable solutions

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• Conceptual and scoping studies • Environmental and socio

economic impact assessment • Permitting and regulatory

compliance • Prefeasibility and feasibility

studies • Detailed engineering • Water management • Bankability studies • Risk analysis

• Mine closure design • Cost engineering • Project planning and scheduling • Project Management • EPCM/PM • Construction QA/QC services

and Inspections • Commissioning and start-up

General Services in MWM

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Specific Services in MWM

Tailings storage facilities

Effluent treatment

Leaching tails

Waste rock dump

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Effluent Treatment

services

• Process modelling for effluent recycle/reuse/minimization

• Conceptual studies for water management

• Conceptual studies for effluent treatment

• Effluent treatment facility design & construction

EPC, EPM, EPCM, BOT

• Development of new treatment technologies

• Laboratory & pilot testing (design-construction-operation)

• Effluent treatment standarised solutions for:

Concentrate filtration

Smelter facilities

• Training & Operation Manuals

• Commissioning and start up

• Technical Expert Review

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Tailings storage facilities services

• Design of Tailings storage facilities (TSF) • Site selection • Tailing distribution systems design • Tailings transport • Tailings reprocessing • Operation advisory • Tailings dam construction • Water balance • Water recovery from tailings • Optimization of tailings facilities, water supply and

related infrastructure • Thickened & Paste Tailings • Filtered /dry stacked Tailings • Pilot Plant (design-construction-operation) • Operation and maintenance manuals • Training courses for plant operators • Instrumentation and monitoring • Basic studies: hydrogeology, geology, geotechnics,

hydrology, rheology, geochemistry and hydraulics • Water management

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Waste rock dump

services

• Site selection

• Geotechnical and geological studies

• Large scale laboratory testing at high confining

pressures

• Materials characterisation

• Basal drainage design

• Waste rock dump design

• Detailed waste landform design

• Stability analysis (2D-3D), static and dynamic

• Leaching operations design for low grade dumped ore

• Water diversion and collection systems design

• Seepage control facilities design

• Foundation treatment (weak soils, permafrost)

• Geotechnical instrumentation and monitoring

• Acid rock drainage modeling and management

• Recommendations for construction and operation

stages

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Leaching tails

services

• Site selection

• Geotechnical and geological studies

• Geotechnical and hydrodynamic characterisation

of ores and leached materials

• Tails dump leach design and stability analysis

• Liner system design

• Solution collection ponds and piping design

• Secondary leaching process design

• Solutions processing

• Metallurgical performance assessment

• Integrated solution circuit analysis and design

• Granular materials acceptance criteria, foundations

inspection, on-site laboratory testing

• Recommendations for construction and operational

stages

• Tails dump instrumentation and monitoring

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MWM experience: Effluent Treatment

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Mining Effluent Treatment Facilities designed by ARCADIS

N° Project Effluent Scope & size Objetive From -> To

1 Punta Chungo Effluent Treatment Plant Minera Los Pelambres

Copper and Molybdenum concentrate filtrated water

Design & Construction Start up Operation Flow: 20 L/s

Mo d : 2-10 0,01 mg/L

2 Puerto Patache Effluent Treatment Plant Collahuasi

Copper and Molybdenum concentrate filtrated water

Design &Construction Start up Operation Flow: 30 L/s

Mo t : 2,0 0,01 As : 1 0,1 S2- : 70 1,0 Cu : 2 0,2 Cd : 0,05 0,01

3 Effluents Treatment Carén Tailings Deposit CODELCO Teniente

Tailing Deposit Clear Waters Basic Engineering Flow: 1500 L/s Plant

Mo d : 2 0,01 Mo t : 3 0,5

4 Effluent treatment plant Smelt and refinery CODELCO Ventanas

Acid Plant Noble Metals Plant Electrolite WTP Cooling Waters Seawage Waters

Design &Construction Star up Flow: 30 L/s

As : 2000 0,2 F : 100 1,0 Se : 400 0,01 Cu : 200 1 Ni : 84 2 Mo : 0,15 0,01

5 Recovered Sea Water Treatment Plant Minera Esperanza

Copper concentrate filtrated water

Design & Construction Start up Operation Flow: 39 L/s

TSS : 1300 130 TOC : 15 1 Cu : 0,26 0,1 Mo : 0,02 0,1 Fe : 1,2 0,05

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Project Description: This treatment facility was designed and built in 1999 in order to reduce Mo and Cu concentration, remove ultra fine solids and adjust the pH value of the copper concentrate filtrate, in order to fulfil the irrigation act. The processes implemented in this facility were a worldwide unique combination of dissolved air flotation and ferric co-precipitation technologies for the removal of dissolved metals. The industrial processes were engineered based on laboratory tests and the design criteria for the industrial facility were defined using a continuous 2 L/s pilot test. The facility was built in a record time for a 25 L/s average flow. In 2010, for an upgrade to 42 L/s a details engineering, terrain engineering and start-up were carried out. Services delivered: Phase I (year 1999) • Research & development of the treatment technology • Pilot plant run • Basic and details engineering • Equipment & material acquisition • Construction & mounting (turnkey) • Start-up • Operating service

Phase II (year 2010) • Study and analysis for the expansion project • Details engineering • Acquisition support • Terrain engineering • Start-up

Project: Punta Chungo Effluent treatment facility Client: Minera Los Pelambres-AMSA Location: North of Chile, Coquimbo Region

To our best knowledge, first plant in the world using DAF for mining effluent treatment

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Project: Support for new regulation compliance Client: VOLCAN Compañía Minera S.A.A. Location: Peru

Project Description: The objective in this project was the definition of the treatment systems necessary to comply with the new environmental regulations for the Andaychagua, Mahr Túnel, Carahuacra, Cerro de Pasco and Animón mining operations. A water management effluent study was carried out, starting from basic site information, flows, streams, qualities, and client’s needs. Processes simulation were conducted by using MatLab – Simulink. The treatment systems were defined based on laboratory testing of the current effluents and ARCADIS experience. Furthermore, the cost, water qualities and flow were estimated for complying with the new regulation. Services delivered: • Effluent quality simulations • Effluent management & optimization • Effluent treatment systems definition • Conceptual & Basic Engineering

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Project: Treatment Plant for Recovered Sea Water Client: AMSA Minera Esperanza Location: North of Chile, Antofagasta Region

Project Description: The Esperanza project uses sea water for the production of copper concentrate on the facility located in Sierra Gorda, 150 km from Antofagasta. The concentrate is sent to the Michilla port for thickening and filtration. Esperanza also uses desalinated water for washing the concentrate filtrated. The overflow obtained from the thickening process is treated in the Recovered Sea Water Treatment Plant, before it is fed to the sea water pipeline that in turns feeds the Sierra Gorda operation. This facility processes 120 m3/h coming from the overflow of the copper concentrate thickener, removing 90% of the ultra-fine material. Moreover, it removes dissolved metals such as copper and molybdenum. The processes used are ferric co-precipitation and dissolved air flotation for the solid-liquid separation. The treated effluent, i.e. sea water, is introduced in the sea water pipeline feeding the Sierra Gorda operation, and the flotation sludge is sent to the filtration facility. Services delivered: • Details engineering • Construction • Acquisitions • Start-up

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Project: Puerto Patache Effluent treatment facility Client: Xstrata – Anglo American Compañía Minera Doña Inés de Collahuasi Location: North of Chile, Tarapacá Region

Project Description: The Puerto Patache facility processes the concentrate filtration effluent, removing principally copper and molybdenum. The objective is to produce water of quality able to comply with the Irrigation Act, regarding elements such as Mo, Cu, Cd, As. Also, to comply with the Effluent Act regarding the sulphide content. The elements removed are concentrated in a semi-solid stream that is sent to the copper concentrate storage. An air based sulphide oxidation technology was developed for this facility, thus eliminating the risks of traditional methods. Services delivered: • Research & development of an air based oxidation technology • Details engineering for the facility • Acquisitions • Construction & assembly (turnkey) • Start-up • Operation service

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Key References

• Alhucema, P., Marinkovic, E., Rubio, J. ”Procesos de remoción de contaminantes desde efluentes de Plantas Concentradoras”. IV Simposio Internacional de Mineralurgia - TECSUP, Perú.

• Gaete, O., Tiravanti, G., 2012. “Nuevas Tecnologías de Tratamiento de efluentes mineros: Precipitación de sulfuros y separación con FAD.

• Gaete, O., 2012, “Obtaining cooling quality water from an acid plant effluent”. Water in mining WIM, Santiago, Chile

• Frenkel, V., Gaete, O., 2112. “Demand in Water Treatment for Mining Industry”. III International Seminar on Desalination ALADYR, Antofagasta, Chile.

• Monares, J.T, 2012. “Operación y testeo de planta piloto de desalación de agua de mar en Singapur mediante sistema de destilación de membrana en condiciones de vacío”. III International Seminar on Desalination ALADYR, Antofagasta, Chile.

• Alhucema, P., Gaete, O., “Con sulfuro y bario”, Revista Induambiente N°115, Abril 2012.

• P. Alhucema, W. Bustos, E. Marinkovic. Rubio, J. “Al rescate del molibdeno”, Revista Induambiente N°20.

• “Tecnología de exportación”. Revista Induambiente N°47, pág. 105-107. • Rubio, J. Tessele, F. Alhucema, P., Marinkovic, E. “Avances y aplicaciones

en la flotación por aire disuelto”. Revista Minerales_Vol 57, pág. 25-27, 2002. • Gaete, O., Tiravanti, G. “Precipitación con sulfuro y separación sólido líquido

con Flotación por Aire Disuelto FAD”. Revista Tecnología Minera (Perú) Edición 32- Julio/Agosto 2012 - pág. 112-115.

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MWM experience: Tailings storage facilities

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It Mine / Deposit Owner Production KTPD

In Operation since (yr)

Final Capacity

Mton

Dam height

(m) Type of tailing Dam

Material Country

1 Los Bronces / Las Tórtolas AngloAmerican 140 1992 1,000 150 Unthickened Tailings sand Chile

2 El Soldado / El Torito Anglo American 20 1993 82 62 Unthickened Tailings sand Chile

3 Salvador / Tranque Austral Codelco 33 1990 275 39 Unthickened Borrow Chile

4 La Candelaria / Candelaria FCX 65 1994 380 180 Thickened Waste rock Chile

5 Collahuasi / Pampa Pabellón

Anglo American, Xstrata 140 1998 1,780 100 Thickened Waste rock &

Tailings sand Chile

6 Andina / Ovejería Codelco 94 1999 2,100 120 Thickened Tailings sand Chile

7 Los Pelambres / Quillayes AMSA 130 1999 248 198 Thickened Tailings sand Chile

8 Escondida / Laguna Seca (OGP1) BHP Billiton 280 1990 4,000 100 Thickened Borrow Chile

9 Caserones Lumina Copper 110 In construction 2,000 220 Thickened

Slimes Borrow/ sand Chile

10 San Vicente SIMSA 2 1998 1,3 19 Unthickened Tailings sand Peru

11 San Rafael / Bodefall III Minsur 2,2 2001 16 90 Unthickened Waste rock Peru

12 Antamina Xstrata/ BHP ~60-90 2002 475 235 Thickened Borrow & Waste rock Peru

TSF designed by ARCADIS (1/2)

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It. Mine / Deposit Owner Production KTPD

In Operation since (yr)

Final Capacity

Mton

Dam height

(m) Type of tailing Dam

Material Country

13 Yauricocha / Chinchán Sociedad Minera Corona S.A. 1 review S/I ~100 Unthickened Tailings Sand Peru

14 Casale Barrick 160 project 1,000 260 Thickened Borrow/ Sand Chile

15 Quellaveco / Cortadera Anglo American 90 Project 1,000 293 Thickened Tailings Sand Peru

16 Potrerillos Plant / Slag deposit Codelco 1.3 Project 2 Filtered No dam Chile

17 Pelambres/ Mauro AMSA 175 2008 1,700 248 Thickened Tailings Sand Chile

18 Victoria Plant/ Chumpe Volcan 8 Project 69 133 High thickened Borrow Chile

19 El Peñon / Meridian 4 2000 50 Filtered No dam Chile

20 Mantos Blancos/ Depósito #3 Anglo American 12/17 Project 110 75 High thickened Waste Rock Chile

21 Mantos Blancos/ Depósito #3 Anglo American 12 2002 20 50 Filtered &

Thickened Waste Rock Chile

22 La Colosa Anglo Ashanti Tailings transport

TSF designed by ARCADIS (2/2)

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Production: 37-62-152 ktpd

Operation started: 1992

Final Capacity: > 1,500 Mton

Final Dam Height: 190 m

Dam Material: Tailings sand

Project: Las Tórtolas Tailing Impoundment Client: Anglo American Chile Location: Center of Chile

Project Description: Los Bronces (currently Minera Sur Andes) is located in the San Francisco Valley. The operation currently processes 152 ktpd of copper ore. The tailings are deposited at the site of the Las Tortolas plant. Las Tortolas tailings impoundment was designed for 1,000 millions tons and it consists of a sand dam of 190 m in height (at final stage) and has two other smaller dams. Services Delivered: • Design of detailed engineering of the tailings impoundment for

the 55 ktpd flotation plant, including three sand dams, tailings transport and distribution systems, and water reclaim and distribution system to the concentrator plant

• Design of conceptual engineering of tailings facilities for 25 and 37 ktpd processing plants

• Design of detail, construction-level engineering of tailings facilities for 37 ktpd processing plant

• Initial filling of the impoundment • Support during construction stage • EPCM New Cycling Stations and Tailings Pipeline

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Project Description: Due to the growth of the pit, Minera Escondida (MEL) has planned to start the operations of a new concentrator plant called “OGP1 (Organic growth project) Plant”. In this context, it is necessary to evaluate the impact to the tailings transport and water reclaim systems with regards to its capacity and distribution scheme. Services delivered • Detailed design of the tailings transport system • Detail Design of the tailings distribution system • Detail Design of the Water Recirculation System. • Construction support

OGP1 Plant Production

155 ktpd

Total production 300 ktpd

New concentrator plant operation start 2015

Project: OGP1 - Tailings disposal and water reclaim Client: Minera Escondida – BHP Billiton , Rio Tinto, JECO Corp, IFC. Location: North of Chile

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Project: Laguna Seca Tailing Impoundment Client: Minera Escondida – BHP Billiton Location: North of Chile

Production: 240 ktpd

Operation started: 2001

Project Description: The Laguna Seca tailings impoundment receives tailings from the 240 ktpd flotation operation at Minera Escondida. ARCADIS designed a clear water pond pumping system for the impoundment. This facility was designed to have clear water, formed with the water released from the tailings discharged on the impoundment. The design allowed to isolate barges, in order to ensure that pumps operate with clear water without solids content. Services Delivered: • Feasibility engineering for water reclaiming system • Detail engineering for water reclaiming system

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Project: Quillayes Tailing Impoundment Client: Minera Los Pelambres Location: North of Chile

Project Description: Los Pelambres plant processed by flotation 85 ktpd of copper ore. The tailings storage facilities include a starter dam 60 m in height and a sand dam with cycloned sand at 900.000 m3/month. The project considers a water diversion tunnel of 4,500 m in length. It has a spillway system that allows for the discharge of more than 300 m3/s. Water is recovered from the pond by towers. Services Delivered: • Study and assessment of alternative sites for the impoundment • Basic studies of hydrology, geology, and geotechnics • Design of basic engineering • Design of detailed engineering • Construction supervision • Commissioning and Start-up • 10 years operation of the facilities

Production: 85 ktpd

Operation started / finished: 1999 / 2010

Final Capacity: 360 Mton

Final Dam Height: 198 m

Dam Material: Tailings sand

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Production: 28 -65 ktpd

Operation started: 1994

Final Capacity: 380 Mton

Dam Height: 180 m

Dam Material: Waste rock

Project: Candelaria Tailing Impoundment Client: Minera Candelaria – Freeport- McMoRan Location: North of Chile

Project Description: The Candelaria tailings impoundment consists of a waste rock dam, 180 m height. The dam is constructed in 2-4 m layers, placed directly on the dam by the mine trucks. The Candelaria tailings operation has the Chilean record in water recovery, i.e. the lowest make-up water use in the industry. Services Delivered: • Analysis of alternatives for the impoundment Feasibility

design of the selected alternative • Pre-basic design engineering studies • Geotechnical study of the tailings deposit area • Environmental study • Basic and detailed engineering design for the dam • Support during dam construction • Design of growth of dam to 800 m.a.s.l.

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Project: Ovejería Tailing Impoundment Client: Codelco – División Andina Location: Center of Chile

Production: 65 ktpd

Operation started: 1999

Final Capacity: 2.100 Mton

Dam Height: 120 m

Dam Material: Tailings sand

Project Description: The Andina Division (CODELCO-Chile) currently processes 94 ktpd of copper ore, while the initial design was 65 ktpd. The Ovejería tailings impoundment consists of a tailing sand dam of 4.200 m length and 120 m height, which results in a tailings storage capacity of 2.100 Mton. Services Delivered: • Feasibility studies of various impoundment sites • Seismic risks study • Geological, hydrogeological, and geotechnical studies • Evaluation of borrow pit areas • Characterization of the tailings sand and dynamic analysis of the

sand dam • Dam design, including starter dam, sand dams, drainage systems,

dam foundation treatment, geotechnical instrumentation • Design of the water recirculation system and pumps, channels and

electrical power to the systems • Design of the cyclone plant, electromechanical installations,

positive displacement pumps, sand and slimes piping system

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Project: Pampa Pabellón Tailing Impoundment Client: Cía. Minera Doña Inés de Collahuasi Xstrata – Anglo American - Mitsui Location: North of Chile

Project Description: The project considered a retaining dam, approximately 6 km length and 90 m of final height. The dam was comprised of waste rock from the dumps. Water recovery considered towers and a tailings distribution pipe along the dam crest. Services delivered: • Review and improvement of existing PFS study, optimization

studies • Water balance for the impoundment • Dynamic analysis and stability analysis of the dam • Evaluation of borrow pit areas • Detail, construction-level engineering design of the tailings

impoundment and associated works • Design of waste rock retaining dam, water intake tower,

pumping system from the tower, dam seepage system, seepage water intake structure, seepage pumping system to booster station, tailings transport and distribution.

• Design of power and instrumentation systems • Preparation of Bid documentation • Operation during the first two years

Production: 60 ktpd

Operation started: 1998

Final Capacity: 1.780 Mton

Dam Height: 100 m

Dam Material: Waste Rock & Tailings Sand

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Project: Chumpe Project Client: Volcan Compañía Minera S.A.A Location: Peru

Project Description: The basic engineering for the Chumpe deposit from Volcan Mining Company considered the design of a new dam to handle the tailing produced from the Victoria plant (Yauli, Perú), which will replace the current tailing deposit at Rummichaca once its useful life ends. The scope of the engineering were the dam, surface water diversion works, tailings transport and distribution, tailings thickening, water recovery systems, and instrumentation. Trade-Off studies were conducted to analyze different alternatives for transportation of tailings and thickening. Services Delivered: • Trade off studies of tailings transport and thickening options • Basic engineering of TSF, cycloning and pumping for backfilling • Onsite geological and geotechnical work, including laboratory

tests to identify the properties of materials. • Support for environmental studies and formalities required for the

management and disposal of tailings.

Production: 8 ktpd

Operation to be started 2017?

Final Capacity: 69 Mt

Final Dam Height: 133 m

Dam Material: Borrow

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Project: La Colosa Project Client: Anglo Gold Ashanti Location: Tolima district, Colombia

Project Description: La Colosa porphyry gold project is located 150km west of Colombia’s capital city, Bogota. The area is characterized by having steep valleys and forest reserve. Trade offs studies were developed to analyze different tailings/ ore transport system options:

• 105 km of ore duct (4 choke station + 6 water pump station) • Belt conveyor (30 km) + tailings duct (35 km)

Services Delivered: Trade-Off Study:

• Plant Location/ Ore Transportation/ Tailings Transportation Mine Facilities:

• Buildings/ Truck shop/ Roads/ Camps

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Key References

• Valenzuela, L. y Barrera, S.,1995, "Grandes Presas de Relaves: Práctica Actual en Chile", X Congreso Panamericano de Mecánica de Suelos e Ingeniería de Fundación, Guadalajara, Méjico

• Barrera, S. 2010. Deposition densities of tailings in Chilean deposits, Tailings and Mine Waste ‘98, Colorado, USA

• Valenzuela, L. y Barrera S., 2000, “Environmental, Operational and Economical Balance in the Design of a Tailings Impoundment”, GeoEng2000 - An International Conference on Geotechnical & Geological Engineering, Nov.‘00, Melbourne, Australia

• Pinto, M and Barrera, S., 2002, “Tailings Beach Slope Forecasting”, Tailings and Mine Waste ‘02 Conference, Fort Collins, Colorado, EEUU

• Alarcón, J.C. and Barrera, S., 2003, “Dams of Great Height, a Challenge”, Symposium on Major Challenges in Tailings Dams, CIGB-ICOLD, June, Montreal, Canada

• Barrera, S. y Campaña, J., (2004), “Análisis de Estabilidad de Presas de Relaves - Práctica Chilena”, 5º Congreso Chileno de Ingeniería Geotécnica, Santiago

• Pinto, M. & Barrera, S., 2008, “Tailings Impoundments – Water Balance – Methodology”. WIM2008. I International Congress on the Water Management in the Mining Industry”, July, Santiago, Chile

• Riveros, C. and Barrera, S. 2009. “Caserones: Option of Tailings Classifying to Improve Water Reclamation”. 12th International Seminar on Paste & Thickened Tailings, May, Viña del Mar, Chile

• Barrera, S., Valenzuela, L. and Campaña, J., 2011, “Sand Tailings Dams: Design, Construction and Operation”, Tailings and Mine Waste 2011 Conference, Nov. 06 -09, Vancouver, Canada

• Ortiz, J, Urquidi, J, Pollak, D and Barrera, S, 2012, “Downstream to Centerline Construction: The Challenge of Change”, Tailings and Mine Waste 2012 Conference, Oct. 16 – 18, Keystone, Colorado

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MWM experience: Waste rock deposits

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Project Description: The expansion of Andina Division (CODELCO-Chile) involves the construction of a 2,800 Mton waste rock deposit, which has a maximum front height of 990 m and rock thickness up to 550 m. The deposit is located at 3,000-3,600 m.a.s.l., within a narrow, high-mountain valley, in an area of high seismicity. ARCADIS designed the waste rock deposit and the water diversion system. The design criteria considered structure stability, environmental sustainability, and cost effectiveness. The design was consistent with different growth rates of the deposit, as required by the expansion project. Also, the design minimized re-handling of waste rock for the closure condition.

Services Delivered:

• Geotechnical characterization of materials under high pressures (laboratory testing with large cells, H = 1.8 m)

• Design and modulation of the deposit consistent with the current and future mining operation and with the existing infrastructure

• Design of the water diversion system

• Design of the basal drain system

• 2D and 3D stability analysis

• Formal dynamics analysis of stability

• Operating Manuals (construction recommendations and restrictions, consideration of climate conditions)

Project: Design of a 2,800 Mton, High-Mountain Waste Rock Dump Client: CODELCO - División Andina

Location: Center of Chile

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Project: Master Plan for San Francisco 2,400 Mton Low Grade Ore and Waste Rock Dump Client: Minera Sur Andes- Anglo American

Location: Center of Chile

Project Description: The mining operation at Minera Sur Andes required preparation of a Master Plan to construct and to operate the San Francisco waste rock and low grade ore deposit. The deposit is designed for a capacity of 2,400 Mton and is located at 3,200 m.a.s.l. (average), within a glacial valley in an area of high seismicity. ARCADIS prepared the Master Plan. The design took under consideration that the low grade ore is deposited on separated areas within the San Francisco deposit and subjected to leaching for copper recovery. Services Delivered:

• Geological and hydrogeological characterization of materials

• Geotechnical characterization of waste rock and foundation materials under

high pressures (laboratory testing with large cells, H = 1.8 m)

• Design of the high mountain water collection and diversion system

• Design of methods for waste depositation on high slope areas

• Design of a high mountain pond for storage and treatment of ARD solutions

• Static and dynamic stability analysis (operation and closure)

• Handling methods for loading waste rock on organic soils

• Recommendations for the treatment of deposit foundations

• Geological risks analysis and feasibility analysis

• Avalanche risks analysis

• Construction recommendations and restrictions

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Project Description: The expansion of Andina Division (CODELCO-Chile) involves the construction of a 2,800 Mton waste rock deposit, located at 3,000-3,600 m.a.s.l., within a narrow, high-mountain valley, in an area of high seismicity. ARCADIS designed the environmental solution required for handling and control of acid rock drainage (ARD) from the waste rock, key aspect which gives sustainability to the Expansion project (currently 92 ktpd of ore, 230 ktpd of ore in the future). The ARD solution developed considered geochemical modeling and engineering design of prevention and treatment works. Services Delivered: • Dynamic modeling of solution and contaminants balance in the waste rock

dump and within the complete solution circuit, down to the control point. The model was used to assess the design criteria and the correct interaction among the different constituents of the environmental solution

• Design of interception works for large amounts of clear water, for both concentrated streams and for diffuse streams, in high slope areas

• Design of conduction and discharge works for deviated water

• Design of collection and conduction systems for ARD solutions generated by the waste rock dump

• Design of all engineering works for the complete solution circuit, including a retaining pond, a seepage control wall, a solution treatment plant (neutralization, HDS technology), and pumping systems for treated water and removal of sludge

Project: ARD Handling in a High-Mountain Waste Rock Dump Client: CODELCO - División Andina

Location: Center of Chile

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Project: Design of Waste Rock Dumps Founded on Weak Foundation Soils

Project Description: In some cases, waste rock deposits must be located on weak foundations, i.e. on rock glaciers in high-mountain settings, on organic soils, and on tailings. Local deformations induced by such weak foundations could promote a sliding triggering mechanism for major failures in waste rock dumps, and rock flows could occur. ARCADIS has devised and proposed recommendations for design and operation. Weak foundations should be avoided, removing the weak material. Also, dedicated sequences for growth of the deposit should be used, encapsulating the weak material area. Foundation treatment is another alternative although not always a practical approach. Special attention should be given to permafrost conditions associated with the melting of ice, due to the high stresses imposed by the dump. Services delivered:

• Geological and geotechnical studies of the foundation soils • Stability and creep analysis validated by topography monitoring • Recommendations for treatment of the foundation soils • Planning of waste loading on rock glaciers and displacement monitoring

S1S2

ROCA

S3S4

S5

S6

S7

S8

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Key References

• Cabezas, R., Sáez, E., y Bard, E.: Modelación Numérica del Comportamiento Mecánico de Lastres Mineros. VII Congreso Nacional de Geotecnia, Concepción, 28-30 Noviembre. 2012, Chile.

• Valenzuela, L.; Bard, E.; Campaña, José. (2011): Seismic Considerations in the Design of High Waste Rock Dumps, 5th International Conference on Earthquake Geotechnical Engineering, 10 – 13 January, Santiago de Chile.

• Bard, E.; Anabalón, MªE. (2010): Comportement de Stériles à Hautes Pressions – Applications au Dimensionnement de Dépôts de Grande Hauteur. Chapitre 4, Livre d´hommage au Professeur Jean Biarez : « Du Sol à l’Ouvrage : une vision multi-échelles de la Geomécanique », Lavoisier, Paris, Francia, 2010.

• Pollak, D.; Bard, E.: (2009): Consideraciones para Diseño Dren Basal de Depósitos de Lastre de Gran Altura, Congreso Sudamericano de Geotécnicos Jóvenes, Córdova, Argentina.

• Bard, E.; Anabalón, MªE. and Campaña; J.: Waste Rock Behavior at High Pressures: Dimensioning High Waste Rock Dumps, Chapter 4 in “Multiscale Geomechanics from Soil to Engineering Projects”, John Wiley & Sons, Inc., USA, October 2011.

• Bard, E.; Anabalón, MªE. (2008): Comportement de stériles à hautes pressions; Journée d´hommage au Professeur Jean Biarez, Comité Français de Mécanique des Sols et de Géotechnique, 12 mars.

• Valenzuela, L.; Bard, E.; Campaña J.; Anabalón, MªE. (2008): High Waste Rock Dumps- Challenges and Developments, 1st International Seminar on the Management of Rock Dumps, Stockpiles and Heap Leach Pads, pp. 65 - 78, 5 - 7 March 2008, Perth, Western Australia.

• Bard, E.; Anabalón, Mª E.; Campaña, J.; Apablaza, R.; Gallardo, M.; (2007): Comportamiento de Lastre ROM sometido a Altas Presiones, VI Congreso Chileno de Geotecnia, Valparaíso, 28 al 30 de Noviembre 2007.

• Bard, E.; Campaña, J.; Anabalón MªE.; Apablaza, R., (2007): Waste Rock Behavior at High Pressures, XIII Pan- American Conference on Soil Mechanics and Geotechnical Engineering, paper 254, Margarita, Venezuela, Julio 2007.

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MWM experience: Leaching tails

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Project: Heap Leach Pads and Dump Leach Basal Drainage Systems Client: Minera Spence – BHP Billiton Location: North of Chile

Project Description: The Spence operation was designed to process 50 kt/d of mixed and sulphide copper ore, to produce 200 kt per year of copper cathodes. The mine commenced production in mid-2006. The Spence project was planned in three phases, involving the sequential construction of sections of the leaching pads in each phase. ARCADIS has been involved in the project since 2007, providing a range of services related to on-off heap leach pads and dump leaching, from specialized geotechnical engineering to on-site construction support, trade-off analysis, and multidisciplinary engineering and cost estimates. Services Delivered: • Evaluation and optimization of the drainage system of mixed and sulphide

leach pads constructed in Phase I of the project • Geotechnical studies • Definition, programming, supervision and analysis of in-situ and laboratory

tests • Development of trade-off studies • Introduction of an innovative solution to improve the bearing capacity of the

cover in both pads • Selection and definition engineering • Detail engineering of the drainage system design for Phases II and III • Cost estimations • On-site geotechnical and construction support • Provide advice for hydrodynamic characterization of the mixed and sulphide

ores leached in the pads as basic background to support design of the aeration system

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Project: Secondary Leach of Heap Leach Tails Client: CODELCO - Radomiro Tomic Location: North of Chile

Project Description: Radomiro Tomic (Codelco-Chile) runs a heap leach operation of crushed high grade copper ore, a ROM dump leach operation for low grade oxides, and a process of secondary leaching of the heap leaching tails in a static heap, to produce a total of 300 kt per year of copper cathodes. ARCADIS has been involved from the beginning of the secondary leach project. Studies were associated to the sequential expansion phases of the tailings deposit, which was designed for 600 Mton of tails reaching a final height of 110 m and covering an area of 5,5 Mm2. Later, studies were conducted by ARCADIS to increase capacity by additional 344 Mton of tails. Services Delivered: • Selection of the base geomembrane as a function of the deposit height (large

scale cut tests) • Testing and assessment of drainage piping under high loading due to deposit

height • Design of the drainage and solution collection systems as a function of deposit

height • Design of a cost-effective mixed cover for the solution basal drainage system • Static, pseudo-static, and dynamic stability analysis • Support to an industrial scale test of tails leaching • Provide stability restrictions to leaching • For expansion, preparation of the deposit foundation, design of earth works for

platforms, design of on-heap road for transport of the spreader. • For expansion, stability analysis, design of drainage and collection systems,

design of de-sanders and solutions ponds • Design of geotechnical monitoring system (phreatic level and drainage pipes)

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Project: Secondary Leaching of Heap Leaching Tails Client: CODELCO - Minera Gaby Location: North of Chile

Project Description:

Minera Gaby (Codelco-Chile) processes crushed high grade copper ore in a on-off heap leach operation. Currently the leaching tails are subjected to secondary leaching in the tailing deposit, to produce a total 140 kt per year of copper cathodes. ARCADIS has conducted studies related to both the design of the tails deposit and the leaching process, including geotechnical characterization of tail samples to estimate material parameters and to assess stability as a function of loading methodology and leaching conditions. The engineering design was aimed to optimize the drainage system and solve interferences with the existing system. Stability analysis were conducted under different secondary leaching scenarios to assess feasibility. Solution and mass balance simulations were run under different processing scenarios to establish copper production, acid consumption, and water consumption. Services delivered:

• Geological and geotechnical studies • Hydrodynamic and geotechnical characterization of leaching tails • Conceptual engineering design of the secondary leaching project • 2D finite elements and 3D stability analysis • Design of the basal drainage system • Dynamic modeling of solution and mass balance, integrating geotechnical and

process requirements and restrictions • Determination of project requirements in following phases • Early works basic engineering design • Construction support • Technical recommendations for the leaching operation • Design of monitoring programs and action plans

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Project Description: Minera Florida (Yamana Gold) processes gold minerals at 70,000 tpm at the Alhué plant. The process involves the stages of grinding and bulk flotation of Au-Zn, agitated cyanide leaching of Au-Zn concentrate, Zn flotation from leach tailings to obtain Zn concentrate, and PLS electrowinning to obtain doré. ARCADIS developed the Tailings Processing Plant project (PTR project) aimed to reprocess 100,000 tpm of Au tailings for metal recovery. The PTR metallurgical process designed was complex and involved hydraulic extraction of tailings from the dams and transport to the PTR plant, classification of re-pulped tailings, grinding and classification in direct closed-circuit, cyanide agitated leaching, Au and Ag recovery in a modern CIP process, elution and regeneration of activated carbon, Au-Ag recovery by EW, detoxification of cyanidation tailings, filtering and washing of tailings, detoxification of filtered solutions, flotation of washed tailings for Zn recovery, and loading the final tailings in the current tailing dam. Services delivered: • Metallurgical characterization of tailings and leaching testing • Detail engineering of the PTR plant, 3D • Innovative design of the ADR circuit by incorporation of a carrousel C system • Operational Manuals and training • Construction support

Project: Gold Recovery Increase at Alhué Plant Client: Minera Florida - YAMANA Location: Metropolitan Region

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Key References

• León, R., Bard, E. Campaña, J., Lagos, M.: Análisis de Tuberías Enterradas – Depósitos de Gran Altura. VII Congreso Nacional de Geotecnia, Concepción, 28-30 Noviembre. 2012, Chile.

• Campaña, J.; Bard, E.; Anabalón, MªE.; León, R., (2007): Geotechnical characteristics of primary and secondary leach copper ore, XIII Pan - American Conference on Soil Mechanics and Geotechnical Engineering, paper 454, Margarita, Venezuela, Julio 2007.

• Bard E., Campaña J., (2004): Aspectos Geotécnicos en el Diseño de Pilas y Botaderos de Ripios Lixiviados. V Congreso Chileno de Ingeniería Geotécnica, Noviembre 2004.

• Bard E., Campaña J., Garrido H. (2003): Caracterización Interfaz de Material Granular y Geomembrana. 12ava Conferencia Panamericana de Mecánica de Suelos e Ingeniería Geotécnica. Cambridge USA, June 22 – 26.

• Andrade C., Bard O., Garrido H., Campaña J.(2000): Radomiro Tomic Secondary Heap Leach Facility, in Slope Stability in Surface Mining, Chapter 48, pp. 427-434. Edited by the Society of Mining, Metallurgy and Exploration, Inc. (SME).

• Bard E., Campaña J., Garrido, H. (2000): Depósitos de Ripios Lixiviados –Caracterización interfaz de material granular y geomembrana. 3er Congreso de Minería del Perú. Huaraz-Perú.

• Campaña, J., Andrade, C., Bard, E. (1999): Parámetros de Resistencia al Corte en un Depósito de Lastre Mineral. XI Congreso Panamericano de Mecánica de Suelos e Ingeniería de Fundaciones, Iguazú, Brasil.

• Andrade, C., Bard, E., Campaña, J., Paredes, L. (1997): Caracterización Geotécnica de Interfaces de Materiales Granulares y Geomembranas, 4º Congreso Chileno de Ingeniería Geotécnica, Valparaíso, Chile, Vol. I, pp 437-454.

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Mining Clients

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Top Mining clients

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