Exterra champions carbon-negative mining with CO2-seizing tech

Exterra Carbon Solutions (ECS) aims to give miners a sustainability shot by converting process waste and carbon dioxide (CO₂) emissions into stable, inert minerals, simultaneously mitigating environmental footprints, rehabilitating mine sites and generating revenue.

“Our mission transcends simply reducing environmental impacts,” asserts Olivier Dufresne, co-founder of ECS, in an interview with The Northern Miner. “We’re converting a potential environmental liability into a productive asset.”

The company’s unique process combines chemical and mechanical procedures, such as grinding and leaching, using standard industry equipment repurposed to transmute feedstock material into saleable products.

In a strategic partnership with Deep Sky, a direct carbon capture company, ECS has pre-sold its entire 2,500-tonne capacity for mineralized CO₂ produced during laboratory tests. This collaboration showcased the technology’s scalability and market viability, according to Dufresne.

With plans to transition from the laboratory desk to pilot scale in the field, ECS has committed to completing a comprehensive scoping study by March 2024 and a detailed feasibility study by 2025.

ECS focuses on Quebec regions rich in serpentine mineral waste from legacy asbestos operations, such as Thetford Mines and Val-des-Sources. The company is leveraging the similarity in the waste material found at the sites to develop a process flow sheet adaptable for efficient processing from both locations.

“Exterra is pioneering the convergence of innovation, environmental stewardship, and industrial progress,” Dufresne said, “and this is just the beginning.”

ECS was established in 2021 by Dufresne and David Fennell to reshape the mining industry by integrating environmentally sustainable and carbon-negative practices into mining operations. ECS was founded with the recognition that traditional mine finance often doesn’t support the extra costs associated with improving the sustainability of mining operations, Dufresne explained.

ECS’s founders saw an opportunity to use the voluntary carbon markets to help finance mine operations more sustainably through carbon credit generation from carbon-negative activities like carbon mineralization within tailings dumps.

Dufresne said the company had completed two initial rounds of funding and is preparing for a Series A offering that would allow it to complete the pilot-scale plant, with a Series B already on the horizon that would ostensibly fund the company through to completion of the prefeasibility study and up to formal project financing negotiations.

Metals from waste

ECS’s main product is a carbon credit that results from physically producing carbonate minerals through its carbon accounting practices. These carbon credits are generated because of the CO₂ mineralization process, which solidifies carbon in a stable and inert form.

Depending on local community preferences, these minerals can be used for various purposes, including site rehabilitation and potentially filling open pits.

The process of CO₂ mineralization further allows the company to extract by-products from the mineral waste, depending on what feedstock was used. Subject to the feedstock’s composition, these by-products can include silica, iron, and nickel, which can be recovered and sold.

“These materials are marketed as low-carbon footprint or carbon-neutral raw materials, offering an additional revenue stream for the company,” Dufresne said.

ECS’s innovation continues with its self-developed carbon accounting methodology explicitly designed for engineered carbon mineralization of mine waste projects. This methodology positions ECS at the forefront of the carbon credit market with what Dufresne calls “the world’s highest-quality carbon dioxide removal credit.”

The company aims to foster a more circular economy regarding metals production.

“We have engineered a scalable solution that adapts to operational scenarios,” Dufresne explains. “Whether CO₂ transport infrastructure exists or not, we can transport magnesium oxide directly to an emitter’s site for immediate mineralization, leaving us with little infrastructure constraints in rolling out our solutions to more remote locations,” Dufresne said.

ECS prioritizes environmental preservation using existing mineral waste, avoiding building new mining disturbances.