Researchers in Australia have developed a new method for gold processing that simultaneously enhances metal recovery and recycles the highly toxic cyanide used in the extraction process. This innovation, created by scientists at Australia’s national science agency, CSIRO, promises to reduce the environmental risks associated with gold mining while also providing economic benefits, addressing two of the industry’s most significant challenges.
The technology arrives as global gold prices reach unprecedented highs, prompting mines to increase production to meet market demands. Gold mining has historically relied on a cyanidation process that, while efficient, poses substantial environmental and public health risks if not managed perfectly. The new CSIRO technology offers a way to improve the sustainability of this widely used method by creating a closed-loop system that recovers valuable materials from waste streams, turning a costly hazard into a recoverable asset.
The Environmental Cost of Gold Extraction
For decades, cyanide has been the chemical of choice for gold producers because it effectively and selectively leaches gold from ore. Despite its efficiency, its extreme toxicity is a persistent liability. Mining operations must manage vast quantities of cyanide-laced waste, known as tailings. Spills of these tailings can be catastrophic for ecosystems and local communities. One of the most severe incidents occurred in 2000 in Romania, when a tailings dam breach released 3.5 million cubic feet of cyanide-contaminated waste into the Tisza and Danube rivers, causing widespread fish kills and polluting drinking water supplies.
Current industry standards require mining operations to destroy the residual cyanide in tailings before the waste is discharged to long-term storage facilities. This detoxification process is a major operational cost and does not recover any of the value from the used cyanide or other materials lost in the waste slurry. The CSIRO innovation targets this specific stage of the process, aiming to transform waste treatment into a value-recovery opportunity.
A Novel Approach to Cyanide Recycling
The ‘Sustainable Gold Cyanidation Technology’ was developed by a team led by CSIRO Principal Research Scientists Dr. Paul Breuer and Dr. Xianwen Dai. Their patented process fundamentally rethinks the role of cyanide in gold leaching. Instead of being a single-use, disposable chemical that must be destroyed, cyanide is treated as a recyclable reagent. This approach significantly lowers the amount of new cyanide that must be purchased and transported to mine sites, reducing both operational costs and the risks associated with transporting toxic materials.
According to the researchers, the technology not only recovers cyanide but also captures other materials that are typically lost to the tailings pond. This includes valuable soluble gold that escapes the primary recovery circuit, as well as other toxic compounds and some base metals. By cleaning these elements from the waste stream, the process results in far cleaner tailings, which further minimizes the long-term environmental risk of storage.
Process Validation
Dr. Dai validated the chemistry and the economic potential of the technology through a month-long, continuous mini-piloting campaign at a bench scale. The successful campaign demonstrated that the system is not just a theoretical concept but a workable process that can achieve the dual goals of improved recovery and detoxification. This moves the technology a significant step closer to being ready for larger-scale pilot testing and eventual commercial deployment in active mines.
Economic and Industrial Context
The development is particularly relevant for Australia, which is the world’s second-largest gold producer and holds the second-largest known reserves. In 2024, the country produced nearly 300 tonnes of gold, an export valued at about $34 billion AUD. With forecasts predicting that earnings could climb to $60 billion AUD in the coming years due to high prices and demand, the pressure to operate sustainably has never been greater. This economic reality creates a strong incentive for mining companies to adopt technologies that can improve their environmental footprint while also boosting their bottom line.
This is not the first time CSIRO researchers have advanced greener gold processing. Dr. Breuer’s team was previously behind a cyanide-free gold recovery process called ‘Going for Gold’, which used a non-toxic alternative called thiosulphate. That work won an Australian Mining Prospect Award in 2014 and was later licensed for commercial use. The creation of the new cyanide recycling method shows a multi-pronged strategy: while the search for cyanide alternatives continues, there is immense value in improving the safety and efficiency of the cyanidation process that remains the global industry standard.
A Growing Trend in Mining Sustainability
The CSIRO technology is part of a broader industry trend toward creating circular economies within mining operations. Other commercial processes, such as the ReCYN system developed by GreenGold Technology, also focus on recovering cyanide, copper, and residual gold from tailings. This method combines several recovery circuits to detoxify tailings while scavenging valuable materials that would otherwise be lost. The emergence of multiple, competing technologies in this space indicates a clear market demand for solutions that address the dual pressures of environmental regulation and economic efficiency.
The Path Forward
With a patent secured and successful bench-scale testing completed, the Sustainable Gold Cyanidation Technology is positioned for further development and commercialization. The next steps will likely involve scaling up the process and partnering with mining companies to build demonstration plants at operational sites. The potential for this technology is to transform a linear process—leach, recover, destroy—into a cyclical one that reduces waste, minimizes risk, and maximizes the recovery of valuable resources, setting a new standard for sustainable practices in the global gold sector.