Biodiversity and interactions of acidophiles: Key to understanding and optimizing microbial processing of ores and concentrates

Mining companies have become increasingly aware of the potential of microbiological approaches for recovering base and precious metals from low-grade ores, and for remediating acidic, metal-rich wastewaters that drain from both operating and abandoned mine sites. Biological systems offer a number of environmental and (sometimes) economical advantages over conventional approaches, such as pyrometallurgy, though their application is not appropriate in every situation. Mineral processing using micro-organisms has been exploited for extracting gold, copper, uranium and cobalt, and current developments are targeting other base metals. Recently, there has been a great increase in our knowledge and understanding of both the diversity of the microbiology of biomining environments, and of how the microorganisms interact with each other. The results from laboratory experiments which have simulated both stirred tank and heap bioreactor systems have shown that microbial consortia are more robust than pure cultures of mineral-oxidizing acidophiles, and also tend to be more effective at bioleaching and bio-oxidizing ores and concentrates. The paper presented a concise review of the nature and interactions of microbial consortia that arc involved in the oxidation of sulfide minerals, and how these might be adapted to meet future challenges in biomining operations.