Courtesy of: EarthTalk®

Dear EarthTalk: I understand that, among mining’s other problems, like providing climate-warming coal and endangering miners’ lives, it is also a serious water polluter. Can you enlighten? — Richard Moeller, Salt Lake City, UT

Mining disasters have grabbed a lot of headlines of late, but mines pose another insidious threat that tends to get little press attention: pollution of the nearby environment which, in turn, threatens the health of the people who live nearby. Environmentalists are particularly concerned about water pollution from mines.

Mining operations use large amounts of fresh water to process recovered ore; the resulting mine effluent is typically a stew of hazardous acid-generating sulphides, toxic heavy metals, waste rock impoundments and water—and it is often deposited nearby in large free-draining piles where it can pollute land and water supplies for decades to come. When this waste water drains into local streams and aquifers, it can kill living organisms and render formerly pristine local waters unsafe to swim in or drink.

This article appears in Mar 24-30, 2011.