Optimal design and planning of heap leaching process. Pdf a methodology for design and operation of heap leaching. Bench scale metallurgical testing of ores for their amenability to vat leaching is similar to that for heap leaching. Now, many projects depend solely on the performance of their heapleaching facilities for successful operations.
Sulfide leaching is a more complex process because of the refractory nature of the sulphide minerals. In an uncertain project environment, process models are used to evaluate a. Regeneration is carried out in a steam atmosphere to minimize carbon degradation due to oxidation. So, cutoff grade for heap leaching is typically much lower than that of a milled ore. This presentation is centered in heap leaching and several real study cases are. Drainage tile or plastic drainpipe can also be buried in fields for this. Improvements in copper heap leaching by use of wetting agents. Geological survey waterresources investigations report 884104 prepared in cooperation with the kansas department of health and environment lawrence, kansas. Heap leaching hl is currently seen as a viable process for extracting valuable commodities from those stockpiles. Where shallow water tables limit the use of leaching, artificial drainage.
Heap leaching definition of heap leaching by merriamwebster. Hearn and robert hoye the full report presents a description of the magnitude and. The leaching of precious metals like gold and silver can be done very easily with cyanide or ozone under ambient conditions. The mining industry is not only facing increasing demand for products, its also facing other issues making it difficult to meet demand through.
Heap leaching operations present lower operating costs compared to typical gold ore milling. Heap leaching is a tried and tested mining technique enabling the processing of different kinds. Estimated water requirements for gold heapleach operations. One of the main components for these structures is the leach pad liner system, where a lowpermeability soil is normally used in combination with a geomembrane to reduce seepage losses. Simulation results are often counterintuitive, and reveal issues that were not previously apparent. A mathematical model for isothermal heap 437 brazilian journal of chemical engineering vol.
Heap leaching is one of several alternative process methods for. Post leaching, the rocks areleft with smaller proportion of minerals that they originally contained. The ore can be processed as coarse rock, normally referred to as a dump leach, or as a crushed ore in a heap leach. Leaching is a chemical process in mining for extracting valuable minerals from the ore.
Heapleach operations must b properly designed, managed, neutralized, and reclaimed to avoid adverse environmental impacts. Mineral beneficiation by heap leaching technique in mining core. Heap leaching definition is a mining process in which metals are leached from a pile of crushed ore by a percolating solution as of sodium cyanide. The vat leaching process vat leaching can be described as leaching in a bathtub inside a building. Precious metal heap leach design and practice oremax. Designing heap leaching for nickel production that. Although this combination of materials has been shown to. Leaching may also refer to the practice of applying a small amount of excess irrigation where the water has a high salt content to. Therefore, these minerals may not reach their ultimate economic extraction if the heap leach design considers only the fastleaching copper oxide. Heap leaching is an industrial mining process of separating precious metals, copper and other minerals from ores. The heap leaching can be adapted to a variety of minerals and climates, so it is essential to carry out a series of tests in order to determine what is the best design for each particular mineral.
If this is an issue, you may have to do supplementary work or benchmark against similar operations. First, bottleroll tests of finely ground material are run. Schroth2 1college of agriculture and life sciences, department of crop and soil sciences, cornell university, 909 brad. Why is there a need to extract a greater percentage of minerals from ores now. Heap leaching experiencebased approach to successful. A very broad range of processes are used for the recovery of valuable metals. Design of the heap leaching reactor in laboratory scale.
Introduction to evaluation, design and operation of. Technique and design specifications for engineered. 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. Since the 1970s and early 1980s, heap leaching has developed into an efficient way to beneficiate a variety of lowgrade, oxidized gold ores. Factors affecting leaching in agricultural areas and an assessment of agricultural chemicals in the ground water of kansas by charles a. Heap leaching is a tried and tested mining technique enabling the processing of different kinds of ores which could not otherwise be exploited under viable economic conditions. Mining waste directive, emphasis is given to emission minimization concepts for the heap leaching. As result, a library of models is now available with application to the whole production chain from blasting to electrowinning. Lessons learnt from heap leaching operations in south america an update by b.
Copper heap leaching testing, interpretation and scale up free download as pdf file test programme overview 5. The progression of metallurgical testwork during heap. Cut drainage ditches in fields below the water table level to channel away drainage water and allow the salts to leach out. Adequate drainage system design for heap leaching structures article in journal of hazardous materials 14712. Medcram medical lectures explained clearly recommended for you. 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. Heap leaching is a hydrometallurgical process that is widely used in the mining industry, in which lowgrade metals, such as copper, gold, silver and uranium, are extracted. With the demand for copper and gold maintaining, or even rising to, high levels, the pressure is onand increasingfor technology to meet the challenges of the industry. Heap leaching is a widely used process in copper, gold and uranium for the pad, heap and stacking design and is directly transferrable to nickel. Heap leaching of gold and silver ores is conducted at approximately 120 mines worldwide. Environmental coordinator, turkish miners association. Pdf leaching is a hydrometallurgical activity widely used in mineral processing, both for metallic and nonmetallic ores, and in soil. Design of a leaching battery the feed to a leaching battery consists of 10,000 kghr containing 70 weight% insoluble solid and the balance solute. Soil structure, crop planting, type and application rates of fertilizers, and other factors are taken into account to avoid excessive nutrient loss.
Modern day heap leaching, which has a relatively low level of energy consumption, is for example. Simply put, leaching generally refers to the removal of a substance from a solid via a liquid extraction media. There certain economic considerations in the design of a heap leach operation in order to obtain optimum conditions. The preferred alternatives in heap design and their motivation are identified as. The second step of this research is doing the nickel heap leaching in the micro industry scale by a variety of laterite sample height 0. Enter your mobile number or email address below and well send you a link to download the free kindle app. Heap leaching as a hydrometallurgical process is one of the cheapest methods and particularly useful in. In agriculture, leaching is the loss of watersoluble plant nutrients from the soil, due to rain and irrigation. A brief note on the heap leaching technologies for the. Low capital and operating costs and simple atmospheric leach processes make heap. It involves a series of chemical processes through which the mineral ores are piled in the form of a heap and a leach solution is spread over the ore surface to leach metal from the heap.
Designelemental development of heap leaching beyond designconsiderations critical to project success. Treatment of ore is sitespecific as determined by metallurgical tests. Reclamation leaching for salinity buildup under dripmicro irrigation of trees pdf leaching. Salinity laboratory, 450 west big springs road, riverside, ca 925074617, united states b agricultural salinity consulting, 17065 harlo hts. Virtually all gold heapleach facilities are designed to operate on a. Copper dump leaching and management practices that.
Pure fsolvent at the rate of 9,000 kghr is used to extract 95% of the solute. Buildup of impurities during leaching is not easy to simulate. Lessons learnt from heap leaching operations in south. Alta metbytes copper heap leach development not as. High impurity levels can cause viscosity problems in sx during very cold weather. Compared to tank leaching, heap leaching has several advantages, including simplicity of design, lower capital and operating costs, and shorter startup times.
United states environmental protection agency hazardous waste engineering research laboratory cincinnati oh 45268 research and development epa600s288005 mar. The progression of metallurgical testwork during heap leach design 31 introduction heap leaching is used extensively for the processing of copper and gold ores. It also includes a bibliography of references directly related to the gold heap leaching process and a complete index. Leaching also takes place in nature where the rocks are dissolved by water. The leaching process requires an adequate and responsible preparation of the area. Developing the model forces a rigorous examination of the process design. Selection of the most suitable heap method, heap design stacking height, pad inclination, lining and compaction testing and method of stacking and reclaiming is done on a project by project basis. The design of heap leach pads involves a variety of components. The process design of gold leaching and carboninpulp. Copper heap leaching testing, interpretation and scale up. The huge heaps described above are sprayed with a dilute solution of sodium cyanide, and this percolates down through the piled ore, dissolving the gold.
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