Star Diamond looks to kimberlite for carbon capture

Star Diamond (TSX: DIAM) is using kimberlite to capture carbon out of the air. The kimberlite comes from the company’s Star-Orion South diamond project near Fort a la Corne, Sask.

The most common mineral in kimberlite is olivine and its serpentine group weathering products. When exposed to the atmosphere, these minerals react with carbon dioxide (CO₂) to form solid mineral carbonates and remove carbon from the air.

The investigation began when the University of Alberta and Trent University were given kimberlites to test. Both sets of tests on samples from the Star and Orion South kimberlites contain between 62.5% and 83.5% lizardite, a serpentine weathering product that reacts with CO₂. The studies indicated that under specific conditions, the lizardite will react can remove significant quantities of CO₂ from the air – as much as 398 kg of CO₂ per tonne of processed kimberlite when fully reacted. CO₂.

According to the 2018 preliminary economic assessment, mining the Star-Orion South kimberlites could recover about 66 million carats of diamond. That necessitates mining some 470 million tonnes of kimberlite over 34 years.

Star Diamond continues to work with researchers at both universities to further investigate this technology. Moreover, the Star and Orion South sites have access to grid power, giving such a mine a small carbon footprint.

“While these results are preliminary, they never-the less indicate that we may be able to extract carbon from the atmosphere by filtering out CO₂ using waste rock as a storage sink,” said Star Diamond interim president and CEO Ewan Mason. “Should this turn out to be the case, we will be exploring the applicability of utilizing the carbon capture and storage refundable tax credits announced by the federal government in its 2022 federal budget as part of our feasibility study planning.”

Former joint venture partner Rio Tinto backed out of the Star-Orion South project in November 2023, leaving Star Diamond with 100% ownership. Rio Tinto exchanged its 75% interest in the project for a 19.9% stake in Star Diamond.

Visit the Star Diamond website.