Key points
- Australia is the second largest global producer of gold.
- A new CSIRO-developed gold extraction process enhances gold recovery while recycling toxic cyanide.
- Reducing cyanide use has significant economic and environmental benefits in managing risks associated with processing waste streams.
Since the modern gold rushes of the 1970s and 1980s, gold has been one of Australia’s major exports. Australia is the second-largest gold producer globally behind China and holds the second largest known gold resources in the world.
In 2024 alone, the nation generated nearly 300 tonnes of gold, worth about $34 billion AUD, making it the fifth-most valuable export.
With current geopolitical instability driving investors to purchase gold and other precious metals to secure their investments, gold prices have reached unprecedented highs.
A recent report forecasts that record prices and growing export volumes will push Australia’s gold earnings to $60 billion AUD in both 2025–26 and 2026–27. If this trend continues, gold could soon rival coal and iron ore as one of the nation’s top exports.
Australia’s mines are now ramping up production to meet market demands, and with more output there is a need to consider the implications of the traditional but toxic leaching methods being used.
Cyanide and gold extraction
Cyanide is widely used in gold extraction as it easily and selectively combines with gold (and silver), making it useful in separating these precious metals from their ore.
However, due to its highly toxic nature it can result in substantial environmental impacts and public health risks if released into the environment.
Since the 1970s, cyanide spills have resulted in major fish kills, contaminated drinking water supplies and harmed agricultural lands.
One of the most catastrophic incidents occurred in Romania in the year 2000. At Aural Gold Mine, a tailings dam ruptured, spilling 3.5 million cubic feet of cyanide-contaminated waste into the Tisza and Danube Rivers. Not only did it kill fish and poison water supplies in the immediate area but travelled as far as 400 kilometres downriver to Hungary and former Yugoslavia.
A need for green in the new gold rush
CSIRO Principal Research Scientists Dr Paul Breuer and Dr Xianwen Dai have developed a patented technology that offers a more sustainable and profitable future for gold processing.
The ‘Sustainable Gold Cyanidation Technology’ is a new process that improves gold recovery while recycling toxic cyanide, delivering both economic gains and environmental benefits.
Dr Dai, who validated the process chemistry and economics of the technology during a month-long, continuous bench scale mini-piloting campaign, believes the innovation is a leap forward for gold processors.
“Our process surpasses the commonly practiced cyanide destruction technology and we are now ready for pilot scale demonstration in the field” said Dr Dai.
Managing cyanide’s toxic risks
Today, the gold mining industry reduces the environmental risks by destroying residual cyanide in the process tailings before discharge to tailings storage facilities.
CSIRO’s new technology further reduces the level of toxic compounds left in the tailings and the amount of cyanide needed to be transported to site, lowering the risk of environmental impacts.
“This technology enables the recovery of cyanide and other toxic compounds, some base metals and valuable soluble gold that typically remains unrecovered in cyanidation tailings,” said Dr Dai.
At the same time, it reduces environmental risks and costs linked to cyanide use, transport, tailings storage, and potential dam failures.”
Track record of sustainable gold recovery innovation
This isn’t the first sustainable gold breakthrough by CSIRO.
Dr Breuer’s team previously produced Australia’s first cyanide-free gold using using a process called ‘Going for Gold.’ This landmark innovation won the 2014 Australian Mining Prospect Award for replacing cyanide with thiosulphate, a non-toxic alternative. They successfully delivered a safer, more sustainable process without the environmental risks of leaking, spillage, or exposure to toxic chemicals.
“On the path to commercialisation, we partnered with small gold producer, Eco Minerals Research, to build a mobile gold processing demonstration plant based in Menzies, Western Australia,” said Dr Breuer.
“The plant enabled us to trial and improve the process to ensure it was robust and practical at scale for commercial operation.”
In 2019, the technology was transferred to Australian company, Clean Mining, which today offers the technology products and licenses to industry. The technology can also replace toxic mercury used by artisanal and small gold miners.
Going for Gold was built on CSIRO's previous work tailoring a niche cyanide-free solution to Barrick Gold's Goldstrike Mine. Successfully operating from 2014 to 2024, the site processed up to 13,000 tonnes of ore per day.
A golden opportunity for Australian gold producers
Dr Breuer and his team are now excited about the sustainable improvements the Sustainable Gold Cyanidation Technology process offers the gold industry.
After a month-long lab-scale pilot testing, the Sustainable Gold Cyanidation Technology is now at Technology Readiness Level 4 and set for scale up.
Dr Breuer and Dr Dai are seeking industry partners for pilot projects and are open to collaborations with gold producers, engineering firms, and suppliers.
“The technology can deliver much greater economic and environmental benefits beyond what is possible with current cyanide recovery and recycling technologies,” said Dr Breuer.
“With sufficient interest we will be able to progress to pilot and demonstration in the field, which will hopefully lead to improved gold yields, environmental outcomes and sustainability for the gold industry.”