The richness of Australia's unique biodiversity has been highlighted with the discovery by scientists from CSIRO and BacTech Pty Ltd, a Perth-based mining biotechnology firm, of indigenous microbes capable of devouring toxic effluent from gold extraction.

The discovery could also pave the way for a major advance in "clean green" processing of minerals such as gold, copper, nickel and zinc from sulphide ores.

Dr Peter Franzmann and Mr Matthew Stott of CSIRO Land and Water and CSIRO Minerals have identified several new species of native microbes able to break down the thiocyanate formed from the cyanide used to extract gold.

The project is funded by the Western Australian Government through its WA Innovation Support Scheme (WAISS), which fosters small innovative enterprises in the State.

Their discovery has led to the development of a process for cleansing the waste streams from inland gold mines, where clean water is often a scarce and costly commodity. Based on a process used by the Homestake mine in the United States, this system uses uniquely Australian organisms adapted to the local conditions.

"We found these bacteria thriving in the tailings ponds of a gold mine in the Western Australian goldfields," Dr Franzmann explains.

Part of the project is to develop a modified bioreactor to process the mine effluent which better suits the local microbes and the specific degradation process.

"We have put them to work in a new system for purifying the waste water, and so far they have managed to reduce the concentration of toxin in the waste-stream 15-fold," he says.

"If we can fine-tune the process a bit more, it will make the water completely re-usable by mines that bioleach refractory ores prior to cyanide gold extraction. Quality water is scarce in WA's gold-producing regions - and any technology which allows us to recycle it will benefit both the
'"/>

Contact: Dr Peter Franzmann
p.franzmann@per.dwr.csiro.au
61-8-9333-6306
CSIRO Australia
28-Apr-1998