Researchers at the University of Waterloo in Ontario, Canada, are developing a new mining technique that uses microbes to recover metals and store carbon from mine tailings, promising an advancement in sustainability.
“We can take tailings that were produced in the past and recover more resources from those waste materials and, in doing so, also reduce the risk of residual metals entering into local waterways or groundwater,” said Jenine McCutcheon, assistant professor in the Department of Earth and Environmental Sciences.
In addition to improving resource recovery, the microbes can also capture carbon dioxide from the air and store it within the tailings as new minerals – a process that can aid in offsetting some emissions released while also helping to stabilize tailings.
“Over time, mining practices have evolved and become more efficient. But the climate crisis and rising demand for critical minerals require the development of new ore removal and processing technologies,” she added.
The process can also help in the cases of old tailings via bioleaching, as the microbes will help break down the ore and release metals not previously fully recoverable. It can be done in this manner in an eco-friendly way, the school stressed, that is notably faster than the natural biogeochemical weathering processes.
The university said that microbial mineral carbonation could offset more than 30% of a mine site’s annual greenhouse gas emissions if applied to an entire mine while also adding value to historical mine tailings that were until this point considered only waste.
“This technique makes better use of current and past mine sites,” McCutcheon said.
“Rethinking how future mine sites are designed in order to integrate this process could result in mines that are carbon neutral from the get-go rather than thinking about carbon storage as an add-on at the end. This technology is a potential game-changer in the fight against climate change, and the mining industry has a unique opportunity to play a significant role in the future of green energy.”