Winsome Resources announced a strategic partnership with carbon removal registry Isometric on Jan. 28, to advance its carbon sequestration strategy for the Renard site in the Eeyou Istchee James Bay region of Quebec. This initiative will also support the development of Winsome’s nearby flagship Adina lithium project, as the company has the exclusive option to acquire the Renard diamond mine—which was idled in 2023—and repurpose its infrastructure to process ore from the Adina project.

Additionally, Winsome has signed memoranda of understanding (MOUs) with Aquarry, Exterra Carbon Solutions and Arca Climate Technologies Inc. to explore various carbon dioxide removal (CDR) technologies for application at the Renard site. The initial focus will be on industrial-scale carbon sequestration using processed kimberlite material stored on-site.

The partnerships are part of Winsome’s broader decarbonization strategy as it aims to transform the Renard site into a dual-purpose facility for both lithium production and carbon management, which would potentially make the operation the first in the world to integrate both activities simultaneously on a large scale.

Chris Evans, managing director of Winsome Resources, said in an interview with CIM Magazine that Renard is an ideal site for carbon sequestration because it has a considerable amount of kimberlite left at the site from its previous diamond operations, which is currently sitting in a storage facility.

Evans explained that the crushed kimberlite is full of magnesium oxide in the form of olivine and serpentine minerals, which can effectively trap CO2. When CO2 reacts with these magnesium-rich minerals, solid carbonates are formed, permanently removing CO2 from the atmosphere.

“Since the diamond operations have stopped and there’s no mining [happening], we can essentially divert all of that infrastructure towards CO2 removal for the next three or so years while we wait for our approvals to turn Renard into a lithium processing operation,” said Evans.

Evans highlighted that while the partnerships are still in the early stages, the companies will begin to conduct on-site testwork in the next two to three months to assess the best use of crushed kimberlite and evaluate the feasibility of their CO2 capture technologies. Following this, Winsome plans to seek federal government funding for the project. Currently, the companies are performing desktop testwork, leveraging data from nine years of operations at the diamond mine.

Harnessing collaborative partnerships

As part of the partnership with Winsome, U.K.-headquartered Isometric will act as the project carbon registry, providing monitoring, reporting and verification services for the CDR initiatives at the Renard site.

Evans explained that Winsome was drawn to Isometric as a partner due to its Open System Ex-Situ Mineralization (OSEM) protocol. The protocol outlines a process in which mine tailings and industrial byproducts are treated to accelerate natural weathering, enabling the durable storage of CO2 while complying with regulatory standards. This protocol will allow Winsome and its partners to generate carbon credits, pending the final decision on Renard, and also potentially create income through these credits.

Vancouver-headquartered Arca intends to implement a technology testing project at the site that aligns with Isometric’s OSEM protocol, which would make the project eligible for carbon credit generation. One of the CDR technologies that Arca will be testing at the site involves an autonomous rover that would churn up the crushed kimberlite to speed up the process of carbon mineralization.

Exterra intends to pilot carbon mineralization technology at the site and will use this opportunity to validate its technology as it works towards advancing commercialization.

In an interview with CIM Magazine, Olivier Dufresne, CEO and co-founder of Quebec-headquartered Exterra, said that the company will be piloting engineered mineral carbonation, a natural process replicated in an engineered setting to sequester CO2 captured from industrial facilities or directly from the air. Exterra’s Reactive Oxide to Carbonate (ROC) technology is designed to take metal oxides from serpentine-bearing mine tailings and transform them into carbonate minerals by combining them with CO2.

“Our technology takes that CO2 and mineralizes it with various types of mine waste, including the kimberlite mine tailings located on the north end of the site,” said Dufresne. He noted that, since the kimberlite is already crushed, it provides a significant advantage for mineral carbonation processes.

Turning mining pits into CO2 assets

Kate Murphy, CEO and co-founder of Aquarry, said in an interview with CIM Magazine that after testing materials from the Renard site in the lab, the company will move into limited-scale field trials on-site in spring 2026.

Aquarry, headquartered in California, U.S., specializes in pit lake alkalinity enhancement, a new approach to CO2 removal. This process entails introducing alkaline materials to flooded surface mines, converting them into carbon removal and storage assets while simultaneously improving water quality.

“These [trials] would be fully contained and intended to scientifically validate that our process is working as intended,” said Murphy. “Then, if all goes well, we could consider a pilot-scale project on the site.”  As part of its work to prepare for its limited-scale field trials, Aquarry will conduct lab work in the coming months, beginning with water sampling from pit R65, which is the only one of Renard’s three pits that contains water.

Murphy explained that the company uses alkaline materials extracted from the bottom of pit lakes, which are dissolved in water to enhance CO2 absorption from the atmosphere. As the CO2 dissolves, it reacts with the minerals to form calcium or magnesium carbonates, which then sink to the bottom of the pit.

Murphy highlighted that the process not only ensures the indefinite storage of CO2 but also makes use of the Renard site, which she said is currently underutilized since mining operations ceased.

“What’s nice about the Renard site is that our material feedstock is available right there next to the pit,” said Murphy. “We don’t really need to be hauling too much material, and we’re fairly light on equipment, so it should be fairly easy from that standpoint.”

She added that another advantage of the Renard site is that there is no water discharge into the environment, explaining that any water from the open pit that the company will be testing is processed through a water treatment plant, mitigating potential environmental impacts.

She emphasized that CDR presents a significant opportunity for the mining industry, not only as a means to achieve net-zero goals, but also as a valuable economic opportunity. As carbon removal expands, she believes the mining industry is well-positioned to capitalize on its byproducts, waste streams and legacy sites.

“One really amazing thing about the CDR start-up world is we all understand that we’re in this together,” said Murphy. “We all want to see this industry grow for the good of the planet, so it’s quite refreshing. I don’t think you see this kind of community in a lot of other industries.”