RECENT ADVANCES IN HEAP LEACH PAD DESIGN

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1 Short Course RECENT ADVANCES IN HEAP LEACH PAD DESIGN When: Monday, October 17, 2016 Where: JW Marriott Hotel Lima, Malecon de la Reserva 615, Miraflores, Lima, Peru Presenters: Sam Allen, Vice President, TRI / Environmental Inc., USA; Michael Milczarek, Senior Soil Scientist, GeoSystems Analysis, Inc., USA/Global Water Experts; Denys Parra, General Manager, Anddes Asociados SAC and Associate Professor of National University of Engineering, Peru; Dirk van Zyl, Professor and Chair of Mining and the Environment, Norman B. Keevil Institute of Mining Engineering, University of British Columbia, Canada. Language: English with simultaneous translation into Spanish. Course Description Mining operations utilize heap leach pads (HLP) for processing low grade ore and obtaining precious and base metals on a cost effective manner. The use of the most recent techniques for geotechnical and hydrodynamics analysis, facility design and geosynthetics quality control, is required for ensure an optimum performance of the facility, mainly when dealing with complex terrain. This one-day short course will introduce and discuss the followings topics: Review of geomembrane types. Exposed and unexposed applications, installation procedures and associated QA, slope stability and puncture protection design and testing. Explanation of electrical resistivity testing technology for leak location, test methods, exposed and unexposed leak location test procedures, leakage rates and leak statistics, impact of leak detection testing and contribution to QA. Geotechnical behavior of heap leach pad related to: soil-geomembrane interface characterization, non-linear shear strength, interface performance with high loads and also topics related to stability analysis, seismic induced permanent deformation, case study and state of the art in 3D stability. Hydrodynamics topics: saturated vs unsaturated flow, how affect the ore permeability on metal recovery, laboratory methods to determine ore permeability, field methods to assess ore permeability and metal recovery and hydrodynamic modeling. Heap leach pad risk assessment. The course is designed for technical personnel involved in heap leach pad analysis, design, construction and operation, taking advantage of the strong experience of the instructors in the specific topics to be covered, which have been successfully applied in several heap leaching projects around the world.

2 Course Program Time Session Topic Presenter 07:00-08:15 Registration / Networking 08:15-08:30 Session 1 Introductions Dirk van Zyl 08:30-09:45 Session 2 09:45-10:00 Coffee break Geomembrane, application, installation and QA Sam Allen 10:00-11:00 Session 3 Leak location Sam Allen 11:00-12:00 Session 4 12:00-13:00 Lunch Soil-geomembrane interface characterization and leach pad stability Denys Parra 13:00-14:00 Session 5 Seismic stability & 3D analysis Denys Parra 14:00-15:00 Session 6 Unsaturated permeability Mike Milczarek 15:00-15:30 Coffee break 15:30-16:30 Session 7 Hydrodynamic modelling Mike Milczarek 16:30-17:30 Session 8 Heap leach risk assessment Dirk van Zyl Session 1: Introductions, Dirk van Zyl Introduction of speakers, opening remarks Session 2: Geomembrane and pipes, Sam Allen Review of geomembrane types Exposed and unexposed applications, installation procedures and associated QA Slope stability Puncture protection design and testing. Session 3: Leak location, Sam Allen Explanation of electrical resistivity testing technology Test methods Exposed and unexposed leak location test procedures Leakage rates and leak statistics Impact of leak detection testing and contribution to QA.

3 Session 4: Soil-geomembrane interface characterization and leach pad stability, Denys Parra Soil-geomembrane interface characterization o Liner system o Large scale direct shear testing Non-linear shear strength o Effect of texture and asperity height o Effect of soil classification o Effect of vertical stress Interface performance with high loads Stability analysis o Failure modes, analysis consideration, seismic coefficient o Cases of stability analysis Session 5: Seismic stability and 3D analysis, Denys Parra Seismic induced permanent deformation o Makdisi & Seed, Bray & Travasarou and Houston et al. o Finite element dynamic analysis Case study: stability and deformation 3D stability o 3D versus 2D slope stability o Cases studies Session 6: Unsaturated permeability, Mike Milczarek Review of important hydraulic processes o Saturated vs unsaturated flow o Air vs solution flow Ore permeability of different mineral and ore types o Effect of ore permeability on metal recovery o Ore permeability criteria for heap leach design and operations Laboratory methods to determine ore permeability o Physical property tests o Saturated flow and unsaturated flow tests o Case study

4 Session 7: Hydrodynamic modelling, Mike Milczarek Field methods to assess ore permeability and metal recovery o Drilling/coring o CPT testing o In-situ tests o Geophysical testing o In-situ instrumentation o Case studies Hydrodynamic modelling o Review of current models o Case study Session 8: Heap leach risk assessment, Dirk van Zyl Risk assessment Instructors Bios MICHAEL MILCZAREK Senior Soil Scientist, GeoSystems Analysis, Inc., USA Mike Milczarek has an MS degree in Soil and Water Science and BS degrees in Chemistry and Environmental Science. He has 24 years experience in developing, implementing, and managing vadose zone and hydrogeologic studies. He has actively managed or participated in a number of heap leach characterization, modeling and monitoring programs to improve metal recovery. He is a coinventor of several new heap leach permeability assessment methods and modeling algorithms for of which patents are under application. He has also given technical workshops on the characterization, design and monitoring of heap leach operations SAM ALLEN Vice President, TRI / Environmental Inc., USA Sam Allen is the Vice President of TRI/Environmental, Inc. (TRI) Geosynthetics Services, an international, independent third party geosynthetics testing and research facility with laboratories and field offices in the USA, China, Brazil and Australia. He is an experienced professional with a background in chemical and materials engineering, with specialization in the field of polymer testing and geosynthetics. He began his career in the geotechnical and construction materials testing field and has broadened the scope of his involvement in environmental engineering to include geosynthetics technology with specialization in laboratory testing operations.

5 DENYS PARRA General Manager, Anddes Asociados SAC; Associate Professor, National University of Engineering, Peru Denys Parra is civil engineer with degree from the National University of Engineering (UNI) in Lima, with post-graduate studies in Japan and Master in geotechnical engineering degree obtained in Brazil. He is General Manager of Anddes Asociados, a Peruvian consulting company, and Associated Professor of Civil Engineering Faculty at UNI. He teaches graduate courses of Soil Mechanics II and Soil Dynamic at UNI. During his 25 years of experience he has performed research and consulting works in geotechnical and civil engineering in projects related to heap leach pads, tailings dams, waste rock dumps and mining facilities, dealing with geosynthetics, foundation analysis, slope stability, seismic response, soil liquefaction, earthquake induced deformation analysis, among others. DIRK VAN ZYL Professor and Chair of Mining and the Environment, Norman B. Keevil Institute of Mining Engineering, University of British Columbia, Canada Dirk Van Zyl has more than 30 years of experience in research, teaching and consulting in tailings and mined earth structures. During that period he was a faculty member for 13 years at four Universities in the US and Canada. For the last ten years much of his attention has been focused on mining and sustainable development. He has been involved internationally in many mining projects. These projects covered the whole mining life cycle, from exploration to closure and post-closure, in a large range of climatic and geographic environments. His present research is in the area of the contributions that mining makes to sustainable development as well as the application of life cycle assessment to mined earth structures.

Tailings dam raise with reinforced walls

Tailings dam raise with reinforced walls Jorge Alvarez Tiburcio Anddes Asociados S.A.C.,Peru ABSTRACT This paper presents the design of a tailings dam raise with reinforced walls lined with geomembrane,