Australasian Science: Australia's authority on science since 1938

Harnessing bacteria to turn gold grains into nuggets

By Andrew Spence

The full text of this article can be purchased from Informit.

A bacteria that re-concentrates gold grains into nuggets is being targeted by researchers for its potential to optimise gold extraction processes from ore, old tailings or recycled electronics.

University of Adelaide researchers in South Australia have been investigating the role of microorganisms in gold transformation – a process known as the biogeochemical cycle of gold – for more than a decade.

Their latest research, published in the journal Chemical Geology, has shown for the first time, just how long this biogeochemical cycle takes and they hope to make to it even faster in the future.

“In the natural environment, primary gold makes its way into soils, sediments and waterways through biogeochemical weathering and eventually ends up in the ocean. On the way bacteria can dissolve and re-concentrate gold – this process removes most of the silver and forms gold nuggets,” said Dr Frank Reith, Australian Research Council Future Fellow in the University of Adelaide’s School of Biological Sciences.

“We’ve known that this process takes place, but for the first time we’ve been able to show that this transformation takes place in just years to decades – that’s a blink of an eye in terms of geological time.

“These results have surprised us, and lead the way for many interesting applications such as optimising the processes for gold extraction...

The full text of this article can be purchased from Informit.