Thousands of Mines With Toxic Water Lie Under the West

DENVER— Beneath the western United States lie thousands of old mining tunnels filled with the same toxic stew that spilled into a Colorado river last week, turning it into a nauseating yellow concoction and stoking alarm about contamination of drinki...

Kim Cofman and her daughters Acacia, 12, left, and Cayenne, 14, try to stir up sludge from the Gold King Mine that covers the bottom the Animas River on Saturday, Aug. 8, 2015, in Durango, Colo., near the 32nd Street Bridge but find the only way to disturb it is to dig into the yellow muck. Toxic waste is still flowing from the Gold King Mine. Jerry McBride/The Durango Herald via AP

DENVER— Beneath the western United States lie thousands of old mining tunnels filled with the same toxic stew that spilled into a Colorado river last week, turning it into a nauseating yellow concoction and stoking alarm about contamination of drinking water.

Though the spill into the Animas River in southern Colorado is unusual for its size, it’s only the latest instance of the region grappling with the legacy of a centuries-old mining boom that helped populate the region but also left buried toxins.

A toxic sludge flows down the Animas River through Durango Colo, on Friday, Aug. 7, 2015, after the Gold King Mine north of Silverton Colo., spilled heavy minerals into the river on Wednesday. Jerry McBride(/The Durango Herald via AP