Minerals processing technology company Extrakt Process Solution’s non-cyanide solid-liquid separation and leaching technology, known as TNS, is being used by gold recovery company Fulcrum Metals as an innovative technology to advance tailings reprocessing; the technology has been deployed to extract precious and strategic metals from its historical mine waste projects in the Kirkland Lake region, of Ontario, Canada.

Extrakt has granted Fulcrum the rights to deploy the proprietary system on legacy gold tailings across Canada’s gold-rich Timmins and Kirkland Lake regions in addition to Fulcrum’s mining sites, explains Fulcrum CEO Ryan Mee.

“The process replaces conventional cyanide leaching and gravity separation with a faster, cleaner and more versatile system. Unlike gravity separation, which depends on the density of minerals, Fulcrum’s method chemically mobilises gold and other metals for recovery, even from complex or finely disseminated ores.”

Mee confirms that initial tests have shown the high recovery of gold and further testing will include newly discovered silver, gallium and tellurium at the company’s Kirkland projects.

No Cyanide

Mee says there is no cyanide involved when using the TNS technology, marking a major shift in reprocessing standards.

While traditional cyanide-based methods require up to 48 hours for leaching and often result in lower recovery rates, Fulcrum’s alternative delivers results in three to six hours while improving recovery rates and reducing the environmental footprint.

The TNS technology also integrates filtration to optimise yield without pre-treatment or energy-intensive regrinding.

Efficiency gains have been made at Fulcrum’s Teck-Hughes and Sylvanite projects, situated in the Kirkland Lake gold region of Ontario, Canada. At Teck-Hughes, gold recovery of up to 59.4% has been achieved in high-level Phase 1 tests – nearly double the efficiency of legacy systems, highlights Mee.

Leach times of three hours represent a reduction in time of more than 80%.

At Sylvanite, recoveries improved by 63% over 2008 cyanide leach test results, with leach durations similarly reduced by over 90%.

Mee says that the economic implications are substantial.

He illustrates that, at a 59.4% recovery rate and a gold price of $2 899/oz, the Teck-Hughes project has a pretax net present value (NPV) of $33-million, with a 21.4% internal rate of return and an estimated three-year payback.

Increasing the recovery rate by 25% boosts the NPV to $75.5-million.

These economics, says Mee, make lower-grade tailings economically viable and create newer opportunities from old waste.

Extrakt developed the technology and is commercialising the technology globally through an alliance with Bechtel Energy Technologies and Solutions, and is testing it with several major mining companies globally.

Fulcrum has conducted on-site validation at its tailings projects in real-world conditions, confirming efficiency and scalability, he enthuses.

Fulcrum is in Phase 3 of its roll-out, focused on optimisation and modular scale-up.

No major bottlenecks have emerged, although optimising the process to variable tailings compositions and packaging it into field-ready systems remains an ongoing task, notes Mee.

From an environmental perspective, the benefits are clear: by eliminating cyanide, reducing leach time and energy use, and operating without excavation or regrinding, the process limits dust, contamination and water consumption.

Consequently, the process lowers the risks typically associated with tailings reprocessing, adds Mee.

The system also supports future land rehabilitation by reducing untreated waste and recovering a wider range of metals; therefore, previously impacted sites can be turned into green spaces or agricultural land, especially benefiting First Nations communities in Canada, he suggests.

“The goal is to reach zero-waste processing. This not only improves environmental, social and governance credentials but [also] positions the company to unlock further value from secondary metals.

“The model also lends itself to replication. While Fulcrum’s agreement with Extrakt covers legacy tailings in Timmins and Kirkland Lake, the company is open to expanding its footprint. With around 70 historic gold mines in the region and countless others globally, the potential to scale is considerable.”

Mee adds that the company sees its approach as a blueprint for the future of gold mining.