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

Abstract

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.

Keywords:

• review paper
• refractory gold ores
• heap leaching
• modeling
• column
• test work

ACKNOWLEDGEMENTS

This work was supported by Placer Dome Technical Services Limited, the Natural Science and Engineering Research Council of Canada (CRD Grant 233710), the British Columbia Science Council through a GREAT scholarship, the Killam Foundation, and the International Precious Metals Institute.

S.C. Bouffard was a Ph.D. candidate with the Department of Metals and Materials Engineering, The University of British Columbia, 309-6350 Stores Road, Vancouver, BC V6T 1Z4, Canada.

Notes

Legend A: agglomeration Ac: acidification Al: alkalination A + I: agglomeration coupled to inoculation B: biooxidation C: continuous Cy: cyanidation F: fresh Dil: dilution G: grinding I: inoculatoin I/F: initial/final Int: intermittent O/F: on/off Neut/dil: neutralization and dilution R: recycle Reg: regeneration Rep: replenished Ri: rinse S: separation Th: thiosulfate Thi: thiourea