There are half a million abandoned mine sites across the western United States, including more than 23,000 in Colorado. Many of them have the potential to expose high-country waterways to runoff from a highly acidic brew of tailings, mine dumps and metal ore. Last week's dump of millions of gallons of fish-killing, heavy-metal gunk into the Animas River is notable on several fronts — including the fact that the Environmental Protection Agency caused the calamity by accidentally breaching a dam at the Gold King Mine — but it's hardly the first toxic release of its kind in the Silverton area.
In 1973, melting snowpack caused a breach in a tailings pond at the Sunnyside gold mining operation, sending thousands of tons of tailings into the Animas watershed. In 1978, a crew exploring a promising vein of gold drilled a borehole too close to the ancient glacial waters sitting on top of the mine. Lake Emma burst into the mine, flooding the workings with water and a million tons of mud, and pummeling a twenty-ton locomotive into scrap. The American Tunnel turned into a geyser, spouting water more than a hundred feet into the air. All that was left of Lake Emma was a crater the length of three football fields. Fortunately, no one was killed; the lake broke through on a Sunday afternoon, when mine crews were at home.
Sunnyside, the last big mining operation in the area, closed in 1991, taking many of the jobs in San Juan County with it. Under a complicated deal with state regulators, the mine's owners spent millions cleaning up the area and sealing off the mine. But that set the stage for decades of finger-pointing about whether rising water levels at nearby mines, including Gold King, were the result of infiltration from the sealed-off (and flooded) Sunnyside mine pool. The environmental challenges and intrigues around the toxic runoff dribbling over years into Cement Creek (an Animas tributary) was the subject of a lengthy feature in Westword in 2005, "What Lies Beneath." That story explains what happened when entrepreneur and mining buff Todd Hennis tried to reopen the Mogul gold mine — and found it discharging 165 gallons a minute of metals-laced water, which he suspected came from the Sunnyside mine pool.
Hennis eventually reached an agreement with Sunnyside, by which its owners would take over and seal off the Mogul. Hennis's San Juan Corporation has since taken over ownership of the Gold King — and, as noted in this Denver Post story, he believes that the toxic runoff at that mine can be traced back to Sunnyside, too. Officials at Kinross, Sunnyside's parent company, have denied any connection between their sealed-off operation and the pollutants now coursing through the Animas.
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Whether the tainted underground pools and streams in the old mining district are interconnected or not, they remain a large headache for state and federal regulators — one that's been decades in the making. Which makes EPA's blunder all the more stunning. Many of Colorado's old high-country mines are ticking time bombs, just waiting to go off. Shoddy private operations (remember Summitville?) can make the problem worse. But nobody expected the EPA, the scourge of polluters everywhere, to be the guys who pulled the plug.