ABSTRACT
ABSTRACT: Heap leach pad design can be affected by many factors including material properties, ore grade, and climate. Often the climate component can be overlooked, but in the case of an extreme environment, the climate can create serious problems with pad operation. In an environment that experiences extreme temperature changes from summer to winter, the design must consider the pad thermal conditions to allow heap operation throughout the entire year. A heap leach pad in northern Mongolia will experience temperatures as low as −40ºC, which would cause the leach solution to freeze within the heap material and freezing of the pregnant leach solution pond. Therefore, year-round operation will require hearing the leach solution with a boiler and maximizing the heating capacity of solar radiation. Through a combination of variably saturated flow modeling, thermal solution modeling within the heap, and thermal modeling of the solution pond, mitigation measures were evaluated as part of the heap leach pad design. The boiler proved to be effective, but excessive heat loss from the pond will require the use of plastic Bird BallsTM on the pond surface to insulate the solution and to maximize solar heating. This paper details the modeling activities and thermal considerations of this heap leach pad design project.
