CSIRO pours gold using cyanide-free process in Australian first

A one-ounce gold ingot from the first gold pour using CSIRO’s cyanide-free process. Image: CSIRO

The Commonwealth Scientific and Industrial Research Organisation (CSIRO) has extracted and produced gold using a non-toxic chemical process free of cyanide and mercury use.

The process replaces cyanide with a non-toxic alternative thiosulphate and a simple process flowsheet.

CSIRO has run the project in partnership with small gold miner Eco Minerals Research at a pilot plant in Menzies in Western Australia. It previously took more than 10 years and $20 million of investment by CSIRO to develop the technology.

Eco Minerals Research managing director Paul Hanna said, “In close collaboration with CSIRO, we’ve gone through the design, engineering and fabrication stages and set up a processing facility in Menzies, delivering the first gold pour in just 10 months, which is a fantastic achievement.

“The first gold is a major milestone in our progress towards becoming one of the world’s first green gold producers.”

While a standard cyanide-based processing plant costs around $30 million, the new technology requires a capital investment of as little as up to $2.5 million to build.

CSIRO chief executive Larry Marshall said, “It could be a game-changer for small gold producers or those looking to get ahead of increasing market demand for greener commodities.”

The CSIRO research team behind the innovation has had commercial success with Toronto-based Barrick Gold, where a cyanide-free gold solution was specifically tailored for the Goldstrike mine in Nevada. The technology has been used to maintain the mine’s production rates for nearly four years.

Meanwhile, global producers are facing increasingly tough regulations that prevent or restrict the use of cyanide due to environmental and health concerns. Several regional agencies in the United States, South America and Europe have banned the use of cyanide for gold extraction.

Eco Minerals Research said the technology holds huge potential in major gold producing countries such as China, South Africa and the US. It may also be applied to other minerals such as silver and copper.

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