Heap leaching had become a fairly sophisticated practice at least 500 years ago. Waste rock is delivered to the waste rock storage areas while ore is delivered to a primary crusher then via conveyors to secondary and tertiary crushesr for further reduction to a sixpointfour millimeter size. Mine reclamation continually improves in nevada mining. The oxide copper ore is piled up on leach pads, which have a slight slope of approx. Mining industry products and solutions maccaferri usa.
The sized ore is then conveyed overland to a doublelined heap leach facility. With lessons learned from the design, construction and operation of numerous heap leach pads worldwide, srk recommends the following for a successful heap leach facility. Heap leach pad cover and facilities monitoring program august 2005 3 3. Heap leach pads are used in the mining industry as an integral component for metal extraction and processing. Interlift liners are becoming more common, principally as a tool to reduce the. Heap leach stacks can near 200m as operations look to more quickly prove and sustain site yield.
Additionally, in peru, heap leach pads are usually built within narrow valleys where its threedimensional nature can influence their seismic behavior. Although heap leaching is a low costprocess, it normally has recovery rates of 6070%. Slope failures on geomembrane liners are far less frequent, but have occurred on landfills, leach pads and liner caps. It is one kind of a mathematical modeling applied for the copper leaching system.
Similar to in situ mining, heap leach mining differs in that it places ore on a. Heap leaching is an industrial mining process used to extract precious metals, copper, uranium, and other compounds from ore using a series of chemical reactions that absorb specific minerals and reseparate them after their division from other earth materials. Barricks pierina mine in peru uses heap leaching to extract gold. Bleiwas introduction this report provides a perspective on the amount of water necessary for conventional gold heap leach operations. Heap leaching means leaching ores that have been mined, crushed, and transported on impervious pads for leaching by sprinkling and percolation of the solution through the ore.
Geotechnical considerations for surface operations 84. A brief note on the heap leaching technologies for the. A brief note on the heap leaching technologies for the recovery of. All staff meet our team engineering analytics, inc. With the incorporation of the contouring module, any heap type geometry may be accurately constructed, including. Heap leach pads are part of the mining process in the recovery of gold, copper, silver, uranium, nickel and several other metals and nonmetals. Understanding the timerateofrecovery dynamics in heapleach operations. Estimated water requirements for gold heap leach operations by donald i. Heap leaching of low grade complex copper sulphide ore bodies must. The calculator commenced on 1 april 2019, replacing the financial assurance calculator. Stability requirements for heap leach pads heap leach pads are mining operation process components that provide for environmentally safe, fully contained, placement of ore to be leached with process solution, primarily cyanide.
Water is required for drilling and dust suppression during mining, for. Develop a site specific design that accounts for such conditions as metallurgy, topography, climate, geotechnics, environmental and closure conditions. Gla provides expert engineering solutions for all of our clients lined containment structures. Costs associated with pollution control and closure heap leaching is a low cost processing technology in the operational phase, but the potentially high costs and often extended time frame associated with the wash down, closure and rehabilitation of spent heap leach pads is often overlooked. Experiencebased approach to successful heap leach pad design. The hydrus1d software package for simulating the onedimensional movement of water, heat, and multiple solutes in. It complements other infomine cost estimating software and publications. Liner system design for heap leach pads sciencedirect. A focused data collection and analysis program was conducted to quantify and determine the location of gold inventory at a commercial gold heap leach pad. Evaluate the heap stability considering these modes of failure. Dump leach pads hold more ore and can usually handle a less flat terrain.
Heap leaching belongs to the group of percolation leaching processes and operates over ground. Leach pad sites are generally selected for a combination of geotechnical and economic considerations. Sonic sampling and well installation of gold heap leach pad. Rehabilitation and restoration of vegetation surface mining 82. Learn about the powerful pcb design software made just for engineers who need tools that can meet any challenge, without compromise. The model deals with the longterm effects of leach recovery. Investigating leaching alternatives for heterogeneous heap leach pads. The stability of the ore lifts is critical in order to avoid potential downhill heap failure.
Often we develop threedimensional geologic models using leapfrog or similar software to assist with the interpretation of geologic features and cross check geologic interpretations. Aquifer characterization in many areas can be enhanced by utilization of well logs collected for oil and gas wells. The pads professional layout browser allows the user to load a pads professional project and view the layout database with full graphical control of the design. All of the materials used in heap leaching process and industry specifications of materials are available globally. In the 1970s the adsorption process for the recovery of gold using activated. The heap leach module performs mass balances around the heap leach process including chemical reactions, precipitation and evaporation, solids and water inventories, heap drainage and control logic. Our teams experience includes over 600 million square feet of geomembrane liner design and construction quality assurance cqa and over 100 million cubic yards of soil designcqa. Heap leaching provides mining operators with a benign. This evolution continues today, as the mining industry responds to new challenges that range from social and political factors including changing regulatory environments and a focus on the social license to operate to financial pressures resulting from volatile commodities markets. Reinforced soil structures within tip and crusher walls may need to withstand loaded vehicles in. For mining projects, we offer services from exploration to mine closure.
Geomembranes gmbs used as base liners in heap leach pads are. Heap leaching is utilized for the recovery of copper, uranium, gold, silver at a very large. This paper presents a case study of a valleyfill heap leach pad of a peruvian mining project where. Leach pad and pond design we design heap leach pads with metallurgical balance in mind, giving operators the ability to monitor pads performance with greater accuracy. Goldsilver heap leaching and management practices that. To support remedial decisions for the tailings storage facility breach at the mount polley mine mpm, a geochemical characterization program assessing the. Xr5 geomembranes are commonly used as mining liners for heap leach pads due to their resistance to sunlight and thermal swings. Heap leaching accomplishes thisbut only with the containment support of geosynthetics.
Infinite slope failure rotational failure translational failure block andor wedge. A projectlevel dynamic model has been developed to simulate heap leach operations from ore. Stacking more ore faster enables faster returns, however, high loads and harsh chemical environments provide limited pad liner interface stabilization options. Heap leaching technical factors for selecting optimum heap. A key question is how many lifts are to be used, are the spent heaps to be removed onoff pads. Dynamic simulation of heap leach flowsheets brett muller and tim newton simulus presented by brett muller brett. Led a 25man local ghanaian team in the installation of 2. Estimated water requirements for gold heapleach operations. Liner system design for heap leach pads researchgate.
We are an independent, international consultancy providing focused advice and solutions to clients, mainly in the earth and water resource industries. Lc50 toxicity sampling will be completed on bc28 on a mwa basis. Lessons learnt from heap leaching operations in south americaan update onoff heap leach padthese facilities use similar pads and collection systems as the permanent pad but each lift is removed after it has been leached. Technical factors for selecting optimum heap leach pad sites. The growth of heap leaching is heavily tied to the massive scale on which mines are being built, with some sites requiring huge investments. The design of modern heap leach pads utilize an engineered liner system that often is a blend of natural and geosynthetic materials in order to achieve a desired performance, such as ore heap stability, solution drainage, and efficient recovery.
For mining projects, srk offers services from exploration through feasibility, mine planning, and production to mine closure. Heap leaching is a lowcost technology used in industrial mining to recover precious metals such as gold and uranium, along with several other highly sought after metals like copper, from their primary resources ores and minerals. Operating experience has demonstrated lag times in the heap from the top elevation until. Safe means of access to be provided and maintained at surface workings 86. Pads downloads and evaluations pads pcb design software. Sustainability free fulltext a brief note on the heap. A comprehensive monitoring program at an industrial bioleaching heap at the. Geotechnical aspects of each facility are analyzed, including settlement and deformation, to provide a stable, longterm configuration. While heap leaching typically has lower recovery rates than conventional milling, the lower capital and operating costs allow lower ore grades to be economically. Copper is typically recovered from these lowgrade ore by means of heap leaching. Investigating leaching alternatives for heterogeneous heap. Lessons learnt from heap leaching operations in south america. Heap leaching for silver is conducted using the same principles and operating practices as for gold, but heap leach operations produce only a small fraction of world silver production.
Leach pads are constructed of asphalt, clay, or synthetic materials. This document is a user guide for the estimated rehabilitation cost erc calculator hereafter the calculator for mining activities in queensland. The xr5 geomembrane is durable and engineered for the very toughest applications and environments that require highstrength membranes, including heap leaching systems. The three main conditions of instability before or during heap leaching are. Heap leach pad cover and facilities monitoring program. The spent ore is then placed in large lifts in a defined topographic area. Also, slope stability evaluations of stacked heap leach pads are performed using standard geotechnical engineering principles and practice. Design and supply of overland conveyors, onoff heap leach mobile stacking system, reclaim system and ripios system, comprising of five overland conveyors, two mobile trippers, one mobile hopper, thirtytwo 38m grasshopper conveyors, two 20m short portables, two 29m horizontal feed conveyors, two 43m horizontal conveyors, two 55m radial stackers and two mobile crossover conveyors for a 2150 t.
Characterization of gold inventory and impediments to recovery at. Heap leaching is an industrial mining process used to extract precious metals, copper, uranium. It is applied as a decision tool for both process design and. Senior level geotechnical engineer with expertise in rock mechanics and slope stability with a track record designing and assessing the stability of open pits, heap leach pads and waste dumps. The use of liners to prevent loss of process solutions is standard industry practice. Srk consulting is an independent, international consulting practice that provides focused advice and solutions to clients, mainly in the earth and water resource industries. Similar to in situ mining, heap leach mining differs in that it places ore on a liner, then adds the chemicals via drip systems to the ore, whereas in situ mining lacks these liners and pulls pregnant solution up to obtain the minerals. Heap leaching involves trickling a leach solution though a bed of ore to extract target metals. Improvements in copper heap leaching by use of wetting agents. Heap leaching technology open research exeter university of. Heap leaching and the water environment does low cost. Technical factors for selecting optimum heap leach pad sites selection of a pad site can have significant, longlasting effects on leaching performance, safety and environmental impact by saeed karimi nasab, azadeh hojat and mohammad reza mollaei fard.
Mining is constantly evolving and adapting in response to societys needs and advances in technology. Copper mine heap leach pad field lining systems, inc. Provide heap leach pad design to include overall height, lift height, lift setback, and containment berm size, or reference this information contained in another report submitted to bmrr. Heap leach operations are relatively small, discrete opera tions compared with other mining operations. This collection provides an overview of some of the impressive capabilities of this affordable design flow. For many decades, there has been a growing demand for heap leaching due to its environmental benefits. User guide for estimated rehabilitation cost calculator. Senior level geotechnical engineer with expertise in rock mechanics and slope stability with a track record designing and assessing the stability of open pits, heap leach pads. Heap leaching with the new model minlp and gams software, as well as the new model named mixed integer nonlinear programming minlp including gams software general algebraic modeling system were utilized for the study of heap design and operational variables for metal recovery.
217 522 988 233 821 929 1130 973 922 1097 459 874 646 73 1264 849 618 1428 1211 984 174 77 574 191 1285 1422 917 496 1403 430 1001