Bacteria could replace toxic chemicals in base metals mining process

Scientists at Flinders University in Adelaide are researching the use of bacteria to fight the environmental problem of acid mine drainage. The bacteria would replace many of the chemicals, like cyanide and xanthates, which are used in the early ‘froth flotation’ phase of separating metals like copper, zinc, lead and tin from ore. That process can leave toxic by-products in tailings dams which can then leach into soil and ground water, a process which contributes the major problem of acid mine drainage. The CSIRO describes acid mine drainage as ‘the consequence of the oxidation of sulphide minerals and transport of the oxidation products by water’. Associate professor Sarah Harmer said the bacteria they were researching were found in the local environment close to mine sites. “We’re using advanced technology to identify the specific naturally occurring bacterium which attach to each kind of mineral and modify its surface properties,” she said. “Acid mine drainage is a significant environmental problem, and an example of where it is a problem is in Tasmania’s west coast, in the Mount Lyell Region.” Mt Lyell is an historic copper mine, established near Queenstown in 1883, but Pr Harmer says acid mine drainage is not confined to that operation. “It’s been calculated that it will cost about $60 to $80 million a year to remediate acid mine drainage sites across Australia alone.” Pr Harmer said the next step is for the Flinders University small-scale experiments to be scaled up in trials by mining companies.

The Age, 16 August 2016 ; ;