HEAP LEACHING
Pushing performance
Whether it be a cyanidation alternative or a refinement of existing technology, the aim of the heap leaching game is to improve recoveries and the operation’ s environmental footprint, Dan Gleeson reports
SandLix is part of Anglo American’ s FutureSmart Mining program and has been specifically developed to economically treat low-grade, complex ores, while being far less energy and water intensive than conventional processes, such as flotation, the company says
The heap leaching sector is a rarity in mining: a sector receiving attention from all stakeholders.
The presence of cyanide in the bulk of heap leaching processes means communities and NGOs are always scrutinising the‘ closed loop’ ecosystems mining companies look to maintain; mining companies themselves are not only following tried and tested leaching pathways but creating their own( examples below); start-ups are looking at clean and green alternatives to the traditional process; and even engineering firms have skin in the game.
Resilient, sustainable leaching
Engineering firms are where it all begins – with Bechtel Energy Technologies’ ongoing backing of Extrakt Process Solutions LLC and its proprietary leaching and solid – liquid separation technology looking to drive the next wave of innovation in mineral processing.
The collaboration between the two firms was formalised in February 2024, when Bechtel and Extrakt agreed to commercialise the TNS™ solid-liquid leaching technology – billed as a breakthrough platform designed to enhance metal recovery, improve water management and reduce environmental impact.
Through this strategic alliance, Extrakt and Bechtel are working together to accelerate the deployment of nextgeneration mineral processing and tailings management solutions. The partnership combines Extrakt’ s TNS and no-cyanide leaching systems with Bechtel’ s global engineering expertise and large-scale project execution capabilities, creating a powerful foundation for sustainable, highperformance mining operations.
Together, the two companies say they are setting a new industry benchmark in water recovery, environmental responsibility and operational efficiency – delivering cleaner, faster and more cost-effective solutions for tailings treatment, resource recovery and mine closure strategies worldwide.
This technology addresses the longstanding challenges of mine tailings, dewatering and product recovery sustainably and effectively, according to the companies. It has undergone extensive evolution, marked by advancements in metal recovery, equipment and water management, and has garnered more than 40 global patents.
Extrakt explains that its process functions through the strong attraction between TNS chemistry and mineral surfaces, which reduces the adhesive forces between silica and bitumen, enabling the bitumen to detach easily under low shear conditions. Because of this unique interaction, the chemistry used in the TNS process is inherently incompatible with hydrocarbons such as bitumen or oil.
This property has been demonstrated in several pilot-scale projects, including the recovery of bitumen from oil sands and the cleaning of hydrocarbon-contaminated sands, such as those tested in Kuwait. The combination of chemical incompatibility and density contrast promotes a distinct phase separation between hydrocarbons and the aqueous TNS solution, allowing efficient recovery and cleanup, the company says.
The tailings technology the company is marketing to the mining community works similarly to enhance water recovery to increase productivity for producers. It also benefits from Extrakt’ s Reagent Management System( RMS™): a technology specifically designed to complete and enhance the overall performance of the leaching technology.
“ Our objective is not just to replace cyanide,” a spokesperson for Extrakt says.“ We aim to modernise the entire leaching process – making it safer, cleaner and compatible with the environmental standards that will define the future of mining.”
Since the initial leaching results were made public, several companies have contacted Extrakt to explore the potential
14 International Mining | NOVEMBER / DECEMBER 2025