As the concentration of carbon dioxide in our atmosphere increases, carbon sequestration is becoming a focus of attention as a possible solution. The term refers to any type of project that removes carbon from the air and puts it into long-term storage someplace else: oceans, soils, empty oil reservoirs.

But the latest carbon sequestration option could turn toxic waste into a climate change solution. Researchers are discovering that mine tailings – the large piles of pulverized dust leftover after mining of substances from nickel to diamonds to asbestos – are a great resource for sequestering carbon.

Mining is an inefficient process, and massive amounts of rock are smashed into tiny particles in order to extract small quantities of the desired product. This finely grained dust is left to sit in huge piles one mines are closed. Scientists have found that the chemical composition of some mine tailings makes them easily bond with carbon from the atmosphere. Mining companies might be able to turn their toxic waste sites into “reactors” that would speed up the tailings’ absorption of CO2.

Canada is at the forefront of this research.

Image credit: U.S. Department of Energy