The gold plant of the future will be powered by renewables, use recyclable water, not need a tailings dam and feature a non-toxic recovery process. At least that is the hope of Jeff McCullough, the co-founder of Clean Mining, and a subsidiary of Clean Earth Technologies which has just raised A$10 million via a pre-IPO capital raise to continue development of its “clean and free gold recovery process” which it believes is “applicable to 90% of gold production”.
McCullough said the technology, acquired from Australia’s national research agency CSIRO in 2019, used a non-toxic, non-flammable thiosulphate reagent to leach gold from ore. It had been under development for about 15 years and undergone intensive laboratory testing.
“Clean gold is using non-toxic reagents, the recovery process is all non-toxic, the stripping process is all non-toxic and the tailings are also non-toxic so they theoretically could be returned to another location; they don’t have to necessarily be onsite,” McCullough told the AusIMM Gold Plant of the Future Symposium 2022 in Sydney, New South Wales.
“Dry tailings [are] an option. The process water is all recycled through the reagent so the better you can dry your tailings, the better your recycling of water and also of the reagent.”
McCullough worked for CSIRO for 14 years. He said Clean Mining maintained a research and development agreement with the government agency. The Clean Mining process could be scaled for a range of throughput levels. Testing could be customised to meet pre-feasibility or feasibility study requirements.
“The technology is applicable to all aspects of gold recovery so in the past 12-18 months we’ve developed a process for leaching a concentrate or high-grade ore,” McCullough said.
Clean Mining has also developed a Clean Gold trademark certification which endorses a cyanide- and mercury-free operation. It recently signed a master agency agreement with NuFortune Gold for the distribution of its Clean Gold technology and reagent in Australia and South East Asia.
“We’ve got very good staff on tap that are ready to complete ore testing, design processing and get you through to production now,” McCullough said.
“So, it’s not a theoretical technology. This is available today.”
