Abstract
The growing demand for critical minerals, essential for production of electronic devices and batteries to power electric vehicles and other clean energy technologies of the future, is putting pressure on sourcing raw materials, such as nickel and cobalt.
As part of Natural Resources Canada’s Critical Minerals Strategy, there is a focus on Mining Value from Waste, with the goal of recovering valuable minerals from waste materials, such as mill tailings. These tailings often contain sulphides, resulting in the potential to generate acidity. Because of this, the tailings must be stored in large ponds that require perpetual treatment to avoid the production of acidic drainage.
Natural Resources Canada’s CanmetMINING branch is conducting bioleaching R&D with the goal of recovering valuable minerals from tailings, while also reducing the toxicity, reactivity, and acid generating potential of the remaining residues, thereby making them more amenable to underground disposal as backfill. Specifically, the bioleaching process will recover the critical minerals, nickel and cobalt, as sulphate salts (battery precursors) from pyrrhotite-rich tailings, and the resulting residue will be more neutral, allowing it to be placed underground as backfill, rather than requiring it to be stored on surface in tailings ponds for perpetuity.
An overview of the research to-date, including the partnership with MIRARCO Mining Innovation to conduct pilot scale R&D, as well as the results of a recently completed laboratory study on the amenability of the bioleaching process residue to be placed underground as backfill will be presented.