Authors: R. Dixon, Hatch Chile, C.A. Garcia, I. Ewart
Abstract
Mine closures involving copper heap leach operations are complicated by the fact that it is very difficult to entirely stop the leaching process because the natural environment is favorable to residual leaching. As a result, the heaps continue to release copper long after mining operations have ceased. A small copper cementation facility is often used to process the copper and acid containing runoff after closure. However, this process has a relatively high environmental impact and is labor intensive and expensive to operate. The low copper concentration of the leachate rules out most other process options. It is proposed that the copper leachate can alternatively be processed directly via electrowinning cells, to produce a copper powder that is of significantly better quality than the copper produced by a cementation operation, and which requires significantly less labor. The process can be run in a closed loop, with the solution depleted of copper returning to the heap, thus avoiding ferrous tailing ponds or ferric neutralization, and significantly improving liquid solutions management.
