HEAP LEACHING
application of its leaching technology for recovering valuable elements from their specific materials or composite wastes.
One of the key pacts was agreed with Fulcrum Metals, which signed a Master License Agreement with Extrakt for the exclusive licensing of Extrakt’ s technology on legacy gold mine waste to develop the
Extrakt Process Solutions’ TNS solid-liquid leaching technology is a cyanidation alternative that offers high recoveries with low leach residence times, according to the company
company’ s tailings projects in Kirkland Lake and across the mining regions of Timmins and Kirkland Lake.
The Timmins and Kirkland Lake gold camps are two of Canada’ s most prolific gold-producing regions, covering over 3,700 sq. km with over 110 Moz of historical production and more than 70 documented mine waste sites.
Following the signing of a mining option agreement for the Teck Hughes deposit announced by Fulcrum on November 30, 2023, the company has been in discussions with Extrakt regarding the use and licensing of Extrakt’ s proprietary non-cyanide technology. Then, on January 24, 2024, Fulcrum entered into a phased development plan with Extrakt to test its technology at its Teck Hughes project.
Extrakt’ s technology, according to Fulcrum, enables the recovery of precious metals from refractory ore without the use of cyanide.
High level testing on tailings from Fulcrum’ s Teck Hughes and Sylvanite projects has demonstrated very positive non-optimised results, with gold recovery rates of up to 59.4 % and leach times as low as three hours. These are breakthrough results compared to previous testing at Sylvanite in 2008 with traditional cyanide methods achieving gold recoveries of 30 % over 48 hours leach times, it said. A non-optimised conceptual study at Teck Hughes, based on 2,000 t / d of tailings processed over a nine-year operation, a 59.4 % gold recovery rate, a six-hour leach time and a gold price of $ 2,899 / oz, previously suggested a pre-tax net present value( 7.5 % discount) of approximately $ 33
million, Fulcrum added. With a process plant design conceptualised and high-level leach test work complete, further optimisation presents additional upside potential through enhanced recovery rates, reduced leach times, vacuum filtration of residue and the recycling of reagents and water – as well as the recovery of additional minerals held in the tailings – it says.
William Florman, President of Extrakt, said:“ We have seen promising results to date in applying our technology to these projects and look forward to working with Fulcrum to develop their projects and further establish our technology’ s ability in Canada’ s highly productive mining districts in Timmins and Kirkland Lake.”
Silver One Resources Inc, meanwhile, is in the process of examining the potential benefits of using Extrakt’ s solutions in a preliminary economic assessment of its Candelaria silver mine in Nevada, USA.
Silver One first referenced the potential use of a“ novel, cyanide-free leaching process” all the way back in April 2024, saying the results of initial metallurgical testing indicated that it could potentially double silver recoveries and cut leaching times with its use. The results of phase two metallurgical testing at Candelaria, announced in February of this year, reinforced this view. The latest tests were conducted on representative samples from the two heap leach pads, as well as from the in-ground mineralisation marginal to the two main open-pits at the project. They showed that EPS’ technology works well both in agitated and column leaching processes, with the technology especially effective in extracting silver from low-grade, processed material from Candelaria’ s heap-leach pads LP1 and LP2, with significantly reduced leach times compared with cyanide leaching.
Gregory Crowe, President and CEO of Silver One, said:“ We are particularly pleased with the results of the column tests which simulate heap leaching extraction methods versus the more expensive agitated leaching techniques. The column tests show that over 60 % of the silver in Candelaria’ s old heap-leach pads may be recovered by using this innovative technology applied to heap leaching methods, compared with previous studies that show only 29 % to 40 % silver recoveries using cyanide leaching. These improved silver recoveries may positively impact the overall economics of the project as significant resources are contained in the leach pads( over 30 Moz of silver in the indicated mineral resource category and over 15 Moz of silver in the inferred mineral resource category).”
He added:“ EPS’ s leaching agents not only improve silver extraction but are also more environmentally friendly and save water by assisting in the dewatering of waste products. The extraction process is simpler and potentially less costly.”
Anglo American aims for precise control
The Anglo American Technical Solutions team is pressing ahead with scale up of SandLix™, a novel heap leach process which, it says, directly addresses some of the most pressing challenges facing the industry when it comes to future copper supply.
The latest large pilot column is now up and running at the Anglo American Technical Solutions facility in Johannesburg, South Africa, which is a central technical and analytical support centre for the mining company’ s global operations, providing process development and testing in disciplines like minerals processing and hydrometallurgy. South Africa’ s ProProcess has also been involved with the pilot, providing fabrication for the column.
Chris Biley, Anglo American VP, Technology Development, said in an online update that the team is continuing excellent scale-up performance seen to date and providing key data for ongoing deployment studies. To date, field work has also included a prototype heap at the El Soldado copper mine in Chile.
16 International Mining | NOVEMBER / DECEMBER 2025