Leaching is defined as the process of extracting a mineral within the use of reagents that dissolve or transform the mineral into soluble salts, to achieve this different processes are used, one of those is leaching in pads, and in this article we see in a brief way some of his particularities.
First the material product of the extraction, whether underground or open-pit, is crushed and deposited in heap leach pads, the areas of these pads are previously profiled in the form of a cone or funnel made of rocks and compacted clay which is lined with an impermeable element that avoids any filtration and in the bottom there are pipes that will later collect the solution from the leached minerals.
Once the material is deposited in the yard, a network of pipes provided for drip irrigation and sprinklers laid to cover the largest possible area to spread the reagent, which will separate the target ore from the rock.
The pads have different residence times according to the watering and crushing capacity of the mine, once this time is completed a new layer of material to be leached is placed which has a smaller area than the previous one and so on creating a pyramid shape or “cake”.
Once the reagent begins to work, gravity will carry the target mineral trapped in an aqueous solution known as a rich or pregnant solution that is typically directed through open channels to the concentrated ore processing plants.
In some mining operations, once the ore is leached from the upper layer of the pads, it is collected and sent to a new area to be leached for a second time.
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