Summary

This review describes heap leach pads. It lists several consulting companies specializing in heap leach pad design, construction and operation. Performance and stability of the pads is also discussed, and links to several software are given.

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PAD DESCRIPTION

The basic components of heap leach pads are described by Hutchinson and Ellison (1992). A recent review of the state of practice of heap leach pad layouts is that by Thiel and Smith (2003). Wikipedia has a brief overview. See also the many papers in the InfoMine library.

CONSULTANTS

I suspect that any reasonable consulting group servicing the mining industry will tell you they have and can design a heap leach pad. All that is needed is the ability to prepare a grading plan, select a liner, specify drains, and establish the slope stability of a heap, write a plausible closure plan, and leave it to the metallurgists and chemist to work out the right solutions to apply when. Maybe, but as always past success is the best indicator of future performance. So here are a few consultants whose heap leach experience is documented in their websites. If I omit your company, be assured this is my oversight, not conscious decision-for I have sought to include all companies I am aware of.

Arcadis is a big company; it is hard to establish their heap leach credentials, but this link provides an interesting case history. Tucson appears to be the center of their heap leach specialist group.

Golder Associates provides a comprehensive suite of services related to heap leach pad design, construction, operation, and closure.

Kappes, Cassiday & Associates in Reno, Nevada provides consulting, testing, and design services for metal heap leaching.

Knight Piesold has undertaken extensive research, testing and analysis on the deformation and collapse capacities of drain pipes, liner systems and their compatibilities with foundation and overliner materials as well as with hydraulic and geotechnical stability of ore piles.

Leach, Inc. will design and supervise laboratory and field test programs to evaluate the heap leaching of copper and gold ores. They have an extensive library of publications that are available on request.

LinRae Consulting Services, Inc offers to undertake design and construction support of heap leach facilities from their Denver office.

O'Kane Consultants have done the work and have written about it. I much admire their innovative approaches.

W. Joseph Schlitt is a consulting metallurgist-hydrometallurgist. He writes the best papers I have read-see the list of publications on his website and the proceedings of the 2006 SME Conference. Here is a quote from his website: W. Joseph Schlitt has 40 years of worldwide hydrometallurgical experience. His experience includes engineering, process assessments, research and development, and plant-oriented studies in the nonferrous industry. Primary emphasis is in hydrometallurgy and chemical processing, particularly copper heap, dump, bio-, and in situ leaching, plus metal value recovery. Additional experience covers other leaching and recovery systems including molybdenum, zinc, vanadium, uranium, nickel and precious metals.

SRK has the specialists, including for example William Gibson in Perth, Australia. And they have worked in the most amazing places-if you have a fast computer and a bit of time download this PowerPoint presentation, enjoy the story of Russian mines, and see what they say on slide 51. And they have written about it-see the book Copper Leaching, Solvent Extraction, and Electrowinning Technology by Gerald Jergensen.

Sinclair Knight Merz is a leading water and environmental consulting company that has applied their skills to heap leach pad water management.

Smith Williams Consultants has over 42 years of domestic and international heap leach pad experience, including permitting, geotechnical site investigation, surface water diversion design, water balance, pad and pond design, and pad closure. They have been involved in design and construction of over 60 heap leach pads, totaling over 300 million square feet (approximately 27.8 million square meters) of leach pad area.

Water Management Consultants describes their proprietary Heap Leach Dynamic Technology as being able to "improve leaching efficiency, increase recovery and lower costs."

Vector Engineering and Mark Smith is the original heap leach pad consultant in my mind. They dominate the South American market for the design, construction oversight, operation, and closure of big heap leach pads. Mark Smith et al have written most of the definitive technical papers on the topic.