Technology innovator Clean Mining has released strong, positive results from worldwide testing of its cyanide-free gold extraction process.
Developed in Western Australia, the leaching process offers miners the holy grail – rapid, cost-efficient gold extraction, high rates of recovery and low environmental risk.
The award-winning solution eliminates the use of toxic cyanide and mercury and the need to manage wet tailings dams. Instead, it uses an inorganic reagent to release gold from ores, leaving a benign, dry tailings residue.
More than 50 ore types from around the world have been tested by the CSIRO, Australia’s national science agency. Results using the reagent show gold recovery rates in excess of 85-95% – often better and quicker than conventional cyanide processing.
Barrick Gold implemented a large-scale thiosulphate based system at the Goldstrike mine in Nevada, US. The technology proved to be robust for the Goldstrike ore but had limited success on alternate ore types. CSIRO was instrumental in the successful development of the Goldstrike process and continued its independent R&D effort to develop a system that was adaptable to a range of ore types. This culminated in a successful pilot plant at Menzies, Australia.
Recent tests show extraction rates are now consistently high across many different ore types that have been sourced from mining operations in Australia, North and South America, Europe, Asia and the Middle East.
The innovative technology is owned, and being rolled out internationally, by Clean Mining, part of the Clean Earth Technologies group.