Peru's third largest copper mine. Gold is also separated here from the copper concentrate. The mine is south of this marker and the leach ponds are located to the north. Leaching and Electrowinning From the mine, leachable ore (containing copper-oxide minerals) is placed directly on lined leach pads where a weak acid solution is sprayed on the surface of the heap. This solution percolates down through the pile of ore and dissolves the acid-soluble sopper. The copper bearing solutions are collected and pumped to a solvent extraction plant where organic chemicals remove the copper from the solution. The resulting electrolyte solution is transferred to the electrowinning process where copper is plated out as a 99.99% pure copper cathode.