THE PROBLEM
In mining, only a small fraction of the material extracted is recovered as ore concentrate, producing the largest global waste stream by volume. Each year, about 500 million tonnes of ultramafic mine waste are generated as byproducts from mining critical minerals such as nickel and cobalt, with an additional 30 billion tonnes in legacy tailings. These tailings, rich in serpentine minerals, have the potential to store 47% CO2 by weight, presenting an opportunity for gigatonne-scale carbon dioxide removal (CDR).
With the demand for critical minerals expected to increase sixfold by 2040, the volume of ultramafic mine tailings is also expected to rise, offering an expanding feedstock for permanent CDR. However, under natural conditions, carbon mineralization in serpentine is slow, with less than 1% of its storage capacity realized. To fully utilize this waste as a carbon sink, technologies that enhance both the capacity and rate of CO2 capture are essential.
