Microbes Cleaning Contaminated Mine Sites

The Microbes That Clean Up Contaminated Mine Sites. One Yukon scientist is working on a homegrown solution to the heavy metals left behind by mining operations

The Yukon Territory was built on gold. Founded when tens of thousands of prospectors flooded north during the great Klondike Gold Rush of 1898, the Yukon's economy continues to rely, more than a century later, on mining for gold and other metals. That comes with some rewards: In the wake of the 2008 crash, while much of the world struggled, the Yukon's economy boomed, as the skyrocketing price of gold had triggered a second gold rush. But it also comes with risks: the uncertainties of a boom-bust cycle, and the potential for environmental disasters left behind after the mines close.

That's where Dr. Amelie Janin comes in. Janin, the Industrial Research Chair at the Yukon Research Centre, is working on homegrown, sustainable ways for mining companies to clean up their messes—specifically, methods to ensure that the heavy metals liberated during the mining process aren't allowed to contaminate the territory's water, plants, and wildlife.

Currently, the majority of mines use a chemical treatment to neutralize the heavy metals left behind by mining operations. It's a reliable process: "We know it really well, we can control it, and we know it works," says Janin. "But it's not necessarily very sustainable." Since 2012, she's been working on a biological alternative, replicating Mother Nature's own cleaning systems: "We want to try to reproduce the mechanisms that are occurring naturally in the Yukon and use them to our advantage."

To accomplish this feat, Janin's created what she calls "bio-reactors." After gathering sediment from local creeks, which contains the microbes that she needs to use as cleaners, and mixing the sediment with gravel, sand, and other materials—maybe wood chips or biochar—in a sealed tube, Janin runs contaminated mine water through the tube. From here, the microbes simply go to work. Various bacteria have different roles in the process: One of them transforms the sulfate that's naturally present in the mine water into sulfide. "And then the sulfide is very, very reactive," Janin explains.

Source: Pacific Standard

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