Canary in the Gold King Mine: legacy of abandoned mines means more spills

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Ronald R H Cohen, Colorado School of Mines

(THE CONVERSATION) You are gazing over the clear stream, thinking of fishing the crystal waters in the Rockies. The next morning, you are stunned to see an orange-yellow sludge covering the stream as far as you can see. Is this the Colorado Gold King Mine spill into Cement Creek of August 5, 2015?

No, this describes the Clear Creek, CO spill of April, 2009 from a private mine or it could be the 1975 or 1978 Cement Creek spills from abandoned mines.

Spills of acid mine drainage (AMD) from abandoned mines have been a problem in the US for over 100 years.

How many other mines are leaking or holding millions of gallons of toxic wastewater? And how can we avoid these types of damaging spills in the future?

To the source

AMD, also known as acid-rock drainage (ARD) and mining-influenced water (MIW), results from the exposure of sulfide minerals, particularly pyrite (also known as fool’s gold), to oxygen and water. Then, biological and chemical reactions generate sulfuric acid and mobilize heavy metals associated with the rocks and ore.

AMD wastewater can be characterized by high acidity, elevated heavy metals as well as...