HEAP BIOOXIDATION OF REFRACTORY GOLD ORES: CURRENT STATE OF THE ART

Heap leaching of low-grade refractory sulfidic gold ores has generated much interest during the last decade. Attention has focused primarily on improving gold extraction, with less concern about understanding how the multiple phenomena that are involved determine the overall sulfide oxidation rate. Varying the conventional operating parameters (flow rate, particle size, height) has had little impact on sulfide oxidation beyond the average of 10–15%/month. Variable aeration flow, adequate supply of carbon dioxide, finetuning of temperatures, well-defined particle kinetics, and a careful balance between coarse and fine ore particles may hold the key to successful commercial practice.