Biooxidation for the treatment of refractory gold ores and concentrates - A Canadian perspective
To date, bacterial oxidation for the treatment of refractory gold ores and concentrates has not been selected for commercial application in North America. The reasons why the domestic mining industry has not adopted this method of pre-oxidation cannot all be technical. Biooxidation is currently the process of choice for 20% of recent refractory gold treatment plants worldwide. If Canada and the United States, where there are no plants, are excluded, the number of recently installed operations employing bacterial oxidation is nearly half. In addition, several pilot plant operations of significant size and rigor have been run in North America and have reported good metallurgical performance and successful scale-up from the laboratory. A review of the biooxidation process and the technical factors affecting the choice and operation of a biooxidation plant for refractory gold treatment is presented. The viability of the biooxidation approach to refractory gold treatment is affirmed through the presentation of the summary of the objectives and results of a recent and comprehensive pilot plant operation conducted in Canada. Reasons for the apparent reluctance of the domestic industry to adopt stirred-tank biooxidation for refractory gold treatment are discussed.