A review of problems in optimizing extraction in gold heap leaching

CIM Bulletin, Vol. 82, No. 927, 1989

R.F. LOPES, Golder Associates, Mississauga, Ontario and P.L LEHOUX, Giant Yellowknife Mines Limited Timmins, Ontario

Unanticipated low recovery or extraction of gggoldfrom heap teachable ore can often be attributed to phenomena such as non-uniform percolation (channelling) of solution through heaps, excessively slow percolation rates due to densification of ore during stacking on the pads and parasitic or competing reactions of the cyanide solution with undesirable elements or geochemical "impurities" in the ore. The nature and causes of these phenomena are discussed in this paper, and it is suggested that geotechnical and geochemical expertise can contribute significantly to a better understanding of the relationship between laboratory results and actual field performance of the leaching process. Recommendations are made for bench-scale metallurgical testing to be complemented by geochemical and geotechnical laboratory evaluations, to ensure more successful heap leach projects.

Mots Clés: Mineral processing, Extraction, , Gold, Leaching, Heap leaching, Ore preparation, Agglomeration