The Heap Leach Solutions 2016 program included over 40 presentations in topical sessions, six keynote addresses, discussion sessions, and social networking functions.
It also included a short course on Recent Advances in Heap Leach Pad Design, presented by 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.
|Igor Gonzáles, VP, Operations, Buenaventura Mining Company, Peru
Opening Keynote: Evolution of Heap Leaching Processes
Igor Gonzáles is a chemical engineer who graduated from the University of Cusco, Peru. He holds a MSc degree in Metallurgy from the New Mexico Institute of Mining and Metallurgy. He started his mining career in 1980 at the Southern Peru Corporation, where he held various positions for 18 years. In 1998 he joined Barrick Gold Corporation where he spent 16 years, 7 of them in Chile as the President of Barrick South America. During this time he was responsible for managing four mines, two projects, and a workforce of 3,500. After spending some time at the Barrick’s Corporate Office in Toronto, Igor returned to Peru in 2014 and joined Buenaventura as the company’s VP Operations. He also serves as the Board Member for Hudbay Minerals, Sierra Metals, Buenaventura and El Brocal.
|Augusto Chung, VP, Projects, Rio Alto Mining, Peru
Topic: Heap Leach Operations and Water Footprint
Augusto Chung is a metallurgical engineer with over thirty years of experience in the mining industry. He obtained his first degree from the National University of San Marcos, Peru. He also holds a Master’s degree in Mineral Processing from Montana Tech, USA; and a PhD in Mining and Project Management from the University of Oviedo, Spain. He is an accredited member of the Metallurgy Chapter, the Association of Mining Engineers and Metallurgists of Australia (AUSIMM). Currently Augusto is Vice President, Projects at Rio Alto Mining. In addition, he serves as a Professor at the University of San Marcos and the School of Management and Economics.
|Denys Parra, General Manager, Anddes, Peru
Topic: Seismic Behaviour of Heap Leach Pads
There are many heap leach pad projects located in highly seismic regions; however, little is known about the material dynamic properties and seismic behaviour of the heap, despite the fact that heap leach pads are much more sensitive to seismic-induced displacements than other mine facilities, due to the critical potential for tearing of the geomembrane liner during seismic events. Topics to be covered during this presentation include dynamic properties, seismic coefficient discussion, seismic records and spectral matching, 1D-2D and 3D seismic response analysis, seismic induced displacement calculation, comparison between rigorous and simplified approach, among others.
Denys Parra is a civil engineer who graduated from the National University of Engineering (UNI) in Lima, Peru, with a specialization in geotechnical engineering in Japan. He holds a Master’s degree in geotechnical engineering from the Catholic University of Rio de Janeiro (PUC Rio), Brazil. Denys has 25 years of experience, most of it in mining projects. His experience includes the development of geotechnical investigations and geotechnical analysis for all civil and mining facilities, including stability analysis, liquefaction, seismic response analysis, consolidation of tailings, numerical modeling, among others. Currently, Denys Parra is an Associate Professor at the UNI in Lima; he is a registered member of the Society for Mining, Metallurgy and Exploration (SME) in the United States.
|Phillip Dalke, VP Peru Operations and Managing Director, Tahoe Resources, Peru
Topic: My Heap Leach Journey
In 1984, Phillip was offered a job working in the mountains of SW Colorado, at a very small gold operation, where heap leach technology was used. Unfamiliar with this process, he jumped at the opportunity. Over fifteen heap leach operations later, he would like to share lessons learned about being a good neighbour, promoting safety, mitigating environmental risks, and maximizing value in heap leach operations.
Phillip spent over three decades working on heap leach operations throughout the Americas. He was educated at Colorado School of Mines and ISU, graduating with a degree in Metallurgy and an MBA. Phillip is passionate about giving back to the community, caring for the environment, teaching the next generation of engineers and operators, and leaving a mine site in better shape than when he arrived. He is currently assigned to Rio Alto in Peru, operator of the La Arena and Shahuindo mines.
|Wenying Liu, Assistant Professor, Department of Materials Engineering, University of British Columbia, Canada
Topic: Modelling Copper Recovery, Total Iron Concentration and Acid Balance in Chalcocite Heap Bioleaching
Chalcocite heap bioleaching is a complex process that utilizes oxidative chemical leaching and microbial activities to extract copper from an ore bed. Mathematical modelling is an effective tool for identifying key parameters that control the leaching performance to achieve optimization. HeapSim is a modelling tool that incorporates multiple sub-processes that occur in a heap under leach, such as the movement of leaching solution, chemical and microbial reactions, and heat transfer, to predict the leaching behavior of the heap. In this study, the HeapSim model was applied to simulate chalcocite heap bioleaching at the Quebrada Blanca mine located in the northern Chile. The Quebrada Blanca mine currently processes secondary copper sulfides, mainly chalcocite, but is considering the processing of primary sulfides, mainly chalcopyrite, in the next few years. The objective of this study was to simulate the current chalcocite leaching and identify the key parameters that control heap temperature, which would provide insights into the possible leaching of chalcopyrite by increasing heap temperature.
The main findings are that the leaching performance indicators used by the model, including copper recovery, copper concentration, total iron, acid consumption, pH and Eh, could be calibrated using the site historical leaching data with relatively high precision. Heap temperature was sensitive to the raffinate temperature and the extent of reaction of finely divided pyrite flotation tails blended with agglomerated ore. When the raffinate flow rate was high (9 L/m2/h), heap temperature was controlled by the raffinate temperature; when the raffinate flow rate was low (1.8 L/m2/h), heat removal by the raffinate solution flow was insignificant, and the heat generated by pyrite reaction accumulated and led to a sharp increase in the heap temperature. For the current chalcocite leaching, aeration was stopped at 250 days and the raffinate temperature was around 25°C. It is recommended that raffinate be heated up to a higher temperature and aeration be maintained for the entire life of a heap.
Wenying Liu’s research areas are within the broader field of hydrometallurgy and environmental engineering. Specifically, she focuses on heap leaching, a series of chemical reactions for extracting valuable metals, such as copper and gold, from ore and separating toxic elements from mine waste materials. Her research utilizes fundamental knowledge in fluid mechanics, transport phenomenon, reaction kinetics and bioengineering. Her current projects include:
- Use of sea water in heap leaching of copper sulphides to save freshwater
- Release of selenium and associated elements from mine waste materials
- Mathematical modelling of heap leach
- Bioheap leaching of gold from refractory gold ore.
Prior to joining the UBC Industrial Research Chair in Hydrometallurgy in July 2015, Wenying completed her PhD degree in Mineral Processing and Environmental Engineering at the University of Queensland, Australia and a postdoctoral fellowship at UBC. She received her B.Eng and M.Eng degrees in China.
|Dirk van Zyl, Professor, Norman B. Keevil Institute of Mining Engineering, University of British Columbia, Canada
Topic: The Forum for Heap Leach Technology and Practice of the 21st Century
Dirk van Zyl is Professor and Chair of Mining and the Environment at the Norman B. Keevil Institute of Mining Engineering, University of British Columbia, Vancouver, BC. Dirk has more than 40 years of experience in research, teaching and consulting in tailings and mine waste rock disposal and heap leach design. During the last decade much of his attention has been focused on mining and sustainable development and mine life cycle management.
Dirk has consulted internationally on 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. Most of this work has been focused on geotechnical and environmental mining engineering aspects to provide solutions for environmental and human health protection.
Dirk has more than 100 publications to his credit; these include papers and book chapters. He has also presented numerous short courses on heap leach design, mining environmental management and mine closure in the US and other countries. He is the recipient of three awards from the Society for Mining, Metallurgy and Exploration (SME). These are the Robert Peele Award (1985), the Distinguished Service Award (1992) from the Mining and Exploration Division, and a President’s Citation (1998). Dirk became a Distinguished Member of SME in 2003. He received the Bureau of Land Management Sustainable Development award in 2005 and the Adrian Smith International Environmental Mining Award in 2006.
Dirk received a B.Sc. in Civil Engineering in 1972 and a B.Sc. (Honors) Civil Engineering in 1974, both from the University of Pretoria, South Africa. He also received M.S. and Ph.D. degrees in Geotechnical Engineering from Purdue University in 1976 and 1979, respectively. In 1998 he completed an Executive MBA at the University of Colorado. He is a registered professional engineer in three States in the US.