Researchers based in Sudbury, Ontario, are actively engaged in expanding the use of bacteria-powered technology to extract valuable metals from old mine waste. MIRARCO Mining Innovation is currently running a pilot facility to test the effectiveness of microbes in breaking down mine tailings, which are the residual rock and sediment leftover from mining activities. This process, known as bioleaching, aims to release critical minerals like nickel, cobalt, and copper.
While bioleaching technology is widely utilized in international mining operations, with approximately 30 mine sites globally employing this method, Canada has yet to achieve full-scale commercial implementation, as noted by Nadia Mykytczuk, the CEO of MIRARCO, which serves as the research arm of Laurentian University. During a recent tour of the 10,000-square-foot pilot facility in Sudbury, Mykytczuk and other experts demonstrated how bioleaching functions.
Despite the significant value of the waste material, companies have hesitated to invest in reprocessing tailings due to the high costs associated with transporting the material back to the smelter. Typically, instead of processing the tailings, they are mixed with water and stored in large ponds, raising concerns about potential long-term environmental risks.
Jaime Kneen from MiningWatch Canada highlighted two primary risks associated with tailings storage: the chemical behavior of the material and its long-term stability. Tailings can potentially generate acid and release metals that may gradually seep into the surrounding environment, necessitating underwater storage. However, this method poses its own risks, requiring stable dams to prevent catastrophic failures like the Mount Polley mine tailing dam collapse in British Columbia in 2014.
Both federal and provincial governments in Canada have emphasized the need for critical mineral development to secure supply chains for clean energy technologies and national defense. Mykytczuk emphasized that bioleaching not only addresses the demand for critical minerals but also offers a solution for mining cleanup. The technology presents an opportunity to extract significant amounts of critical minerals from mine waste quickly, contributing to a sustainable mining industry.
The bioleaching process involves grinding down tailings and mixing them with a liquid solution to feed bacteria, which then break down the minerals. The resulting slurry undergoes a series of reactions in reactors to extract the metals in liquid form. Researchers are working to replicate this process on a larger scale for practical mining operations.
In another section of the Sudbury facility, scientists are developing bacteria tailored for bioleaching. Different microbes are designed to target specific minerals in mine waste, with some adapted for highly acidic conditions to break down sulfide tailings. The extracted metals can potentially be repurposed for industrial applications, demonstrating commercial viability and value.
The research team aims to transition from pilot testing to full-scale bioleaching operations in Canada within the next two to three years, aligning with global efforts to advance sustainable mining practices.