A team of researchers in Sudbury, Ontario, is currently focusing on expanding the use of bacteria-powered technology to extract valuable metals from old mine waste on a larger scale. MIRARCO Mining Innovation is operating a pilot facility to investigate how microbes can break down mine tailings, which are the leftover materials from mining operations, and release important minerals such as nickel, cobalt, and copper through a process called bioleaching.
While bioleaching technology is widely utilized in international mining with around 30 sites globally, Canada has not yet fully implemented it on a commercial scale, as stated by Nadia Mykytczuk, the CEO of MIRARCO. The pilot facility in Sudbury, spanning 10,000 square feet, was showcased during a recent visit by CBC reporters to demonstrate the bioleaching process.
In Sudbury alone, the mine tailings harbor an estimated $8 billion to $10 billion worth of nickel, highlighting the significant economic potential of reprocessing this waste material. Despite the value, companies have been hesitant to invest in reprocessing due to the high costs associated with transporting the material back to smelters. Typically, tailings are stored in large ponds mixed with water, raising concerns about potential long-term environmental risks.
Jaime Kneen from MiningWatch Canada highlighted the environmental risks associated with these tailings, emphasizing the potential for chemical reactions that could lead to the release of hazardous metals into the environment. To mitigate these risks, tailings are often stored underwater, but this approach presents its own challenges, such as the necessity for stable dams to prevent catastrophic failures like the Mount Polley mine tailing dam collapse in British Columbia in 2014.
In response to the growing demand for critical minerals for clean energy technologies and national defense, both federal and provincial governments are urging the development of critical mineral resources to enhance supply chains and reduce dependence on unreliable suppliers. Mykytczuk pointed out that bioleaching not only addresses the demand for critical minerals but also contributes to mining cleanup efforts.
The bioleaching process involves grinding down tailings and mixing them with a liquid solution to feed the bacteria, which then break down the minerals, facilitating the separation of metals into a liquid form. The resulting slurry undergoes a series of reactions in reactors to extract the metals. The extracted metals can be utilized for various industrial applications, showcasing the potential of this technology in the mining industry.
Efforts are underway in other parts of Canada, such as Nunavut and northern Alberta, to explore bioleaching applications for extracting rare earth elements and other valuable minerals. These projects receive support from the federal Critical Minerals Research, Development, and Demonstration program to advance technologies closer to commercial utilization.
Furthermore, researchers are investigating ways to repurpose the remaining waste material after bioleaching for construction or backfilling in mining activities. The team is also developing strategies to turn the extracted metals into commercially viable products with industrial applications, aiming to transition from pilot testing to full-scale operations in the coming years.
