Can Toxic Mining Waste Help Remove CO2 from the Atmosphere?

On the coast of Newfoundland, waste from a shuttered asbestos mine has been a troubling source of contamination for decades. Now, a company plans to process the waste to draw CO2 from the air — one of several projects worldwide that aim to turn this liability into an asset.

Just outside Baie Verte, a tiny town on Newfoundland’s rocky north coast, a 50-ton toxic liability lingers like a bad dream.

In the mid-20th century, a local prospector discovered asbestos in the hills above the bay. The Advocate mine opened in 1963 and became one of Canada’s largest asbestos producers, providing mineral fiber for insulation and fire-resistant materials. But as asbestos’s health risks—which include mesothelioma and other lung diseases—became clear, global demand for the mineral dropped, and in 1995 the mine closed.

“There’s a stigma now to the town,” says Trina Barrett, who grew up in Baie Verte. As a child, her father worked in the mine, as did most of their neighbors. When the mine shuttered, those jobs disappeared.

But the mine’s waste rock and tailings have stuck around. Mounded into a pile a half-mile long, the tailings are considered too big to address yet too dangerous to ignore. Rain and wind are dispersing tailings into the air and water over time, scientists say; occasionally, kids will ride dirt bikes or ATVs on the mound, kicking up dust that can blow for miles. Now, Barrett is hoping not only to clean up the waste but to use it as a way to tackle climate change.

>> In Other News: Metacon Announces AiP for Ammonia Cracking Tech Use in Maritime Propulsion

Barrett is the cofounder of BAIE Minerals, which is one of a number of new companies worldwide aiming to extract critical minerals from mining wastes and use what’s left over to draw carbon dioxide from the atmosphere.

“This is environmental injustice in my hometown,” says Barrett. “[We] want to actually help make it right and fix the problem, because my community is wearing this.”

A report found that asbestos tailings in Canada and the United States could remove up to 750 million tons of carbon dioxide.

Many mined materials, including nickel, platinum, diamonds, and asbestos, are found in so-called ultramafic rock: rocks that are high in magnesium, an alkaline metal. After mining companies extract the targeted materials, they bulldoze the magnesium-rich leftovers into enormous tailings piles, where that material reacts with atmospheric carbon dioxide to form magnesium carbonate, a solid. This “new” rock can permanently sequester that carbon—whether in the earth or, potentially, in uses like concrete.

This process, commonly referred to as carbon mineralization, occurs in nature, but it happens over a much longer time scale—hundreds or thousands of years. But as the planet warms and scientists call not only for cutting the use of fossil fuels but also removing carbon dioxide from the atmosphere, more and more companies are investigating how to speed up carbon mineralization, either by breaking up alkaline rocks with heat or chemicals to create more surface area or by moving air through large piles of tailings.

The business case for carbon mineralization rests on the sale of carbon removal credits and the sale of tailings byproducts, like silica and nickel, for use in construction and electrification. “That’s what’s going to make these projects happen, if there’s enough funding [from either of these revenue streams],” says Abby Lunstrum, research associate at the Clean Energy Conversions Laboratory at the University of Pennsylvania, where researchers are investigating carbon removal using asbestos tailings and other sources.

A 2022 report by the Lawrence Livermore National Laboratory estimated that existing asbestos tailings in Canada and the United States could remove up to 750 million tons of CO2 in total—while also removing an environmental health hazard.

“It’s potentially a win-win situation on so many different levels,” says Lunstrum.

BAIE Minerals cofounder Mike Sullivan says the company’s primary aim is to extract critical minerals such as magnesium and silica from the tailings for use in cement, fertilizer, and other industrial purposes. That will involve wetting the tailings so that they don’t become airborne and then leaching minerals from the tailings using an acid solution. Eventually, the company will also begin using tailings for carbon removal, potentially using the microwave method.

In Val-des-Sources, Quebec, Montreal-based Exterra Carbon Solutions opened a pilot facility to process asbestos tailings from the region’s mines in March 2024. The company treats tailings with a strong acid to disintegrate the asbestos fibers and extract silica, nickel, and other desired metals. What’s left is high-purity magnesium oxide, which absorbs 1.1 tons of CO2 per ton of material and forms magnesium carbonate. According to CEO and cofounder Olivier Dufresne, the process allows absorption of CO2 “within a few hours.”

Dufresne said the pilot facility can currently process around 200 pounds of tailings an hour, producing about 300 tons of magnesium oxide per year. The company says it aims to build a full-scale facility in 2027.

BAIE Minerals plans to establish a demonstration project at the community college in Baie Verte this year.

Amanda Humby, chief administrative officer of the town of Baie Verte, says that the town’s priority is residents’ safety. Any tailings project that goes forward will need oversight from both the town and the province, she says. But she’s “cautiously optimistic” that the BAIE Minerals project could deliver a solution for the community.

Natural Resources Canada considers carbon mineralization a sector with long-term growth and export potential. Agency spokesperson Maria Ladouceur said in an email that the specific safety measures and regulations for carbon mineralization of tailings will depend on the type of mine waste being used.

Mick Breen isn’t convinced.

Breen grew up in Baie Verte. While he left after high school, he still has a place in town and comes back regularly to visit his mother (his father, who worked in the mine, died in 2023). Breen is frustrated by the province’s lack of reclamation on the site. “If you go down there now, all that’s missing is the big heavy-haul trucks. It looks the same as it was when it was in operation.” He is skeptical that BAIE Minerals has the technology it needs to use the asbestos safely.

To help reassure residents that the mine site can be safely remediated, BAIE Minerals plans to establish a demonstration project at the community college campus in Baie Verte this year. But if there are health effects from using asbestos for carbon removal, says Paul Demers, director of the Occupational Cancer Research Center in Toronto, it could take about 30 years for those impacts to manifest.