New research has revealed that microscopic organisms could play a significant role in managing and potentially unlocking value from mining waste, which is predicted to rise significantly as the demand for critical minerals accelerates.
Researchers from Monash University discovered that naturally occurring microbes are actively breaking down decades-old uranium and rare earth mine waste in South Australia’s Flinders Ranges, transforming previously stable radioactive and toxic metals into mobile nanoparticles capable of moving through soil and water.
Monash University professor of synchrotron geosciences Joël Brugger said the findings challenge long-held assumptions about the stability of abandoned mine sites.
“We have traditionally assumed that these toxic metals were securely locked away by nature in these arid environments, but these tiny organisms are proving us wrong,” Brugger said.
“They are essentially acting as microscopic factories, breaking down stable minerals and mobilising elements like uranium into the surrounding ecosystem. As we ramp up mining for the green energy transition, we must factor these invisible biological processes into our waste management strategies to prevent long-term environmental damage.”
The study examined historic uranium and rare earth element waste in a cluster of historical, abandoned mine shafts, including the Mount Painter No. 6 Workings site in the Arkaroola Wilderness Sanctuary, which has been left largely undisturbed for more than 80 years.
It was previously believed that uranium and rare earth elements in these dry environments remained safely locked within insoluble phosphate minerals. However, advanced single-particle analysis revealed high concentrations of polymetallic nanoparticles near the surface of the waste piles.
The research team found the greatest concentrations of these nanoparticles coincided with areas of highest microbial diversity, suggesting specialised microbial communities are effectively extracting metals from stable minerals and converting them into forms that can be transported through the environment during rainfall.
The researchers said understanding these biological processes will be essential to minimising long-term environmental risks as mining waste volumes increase.
Additionally, the researchers said the newly identified interactions between microbes and minerals could also one day support low-impact extraction technologies or new approaches to remediating contaminated mine sites.