A U.S. Environmental Protection Agency team working to address seepage at an abandoned Colorado gold mine underestimated water pressure at the site before triggering a blowout that sent toxic waste into rivers, according to an internal report released by the agency on Wednesday. The Aug. 5 blowout at the Gold King Mine located on a creek outside Silverton in southwest Colorado sent more than 3 million gallons (11,360 cubic meters) of acid mine sludge into the nearby Animas River, with the plume later flowing from the Animas into the San Juan River in New Mexico. The spill of bright orange wastewater, which carried high concentrations of heavy metals such as arsenic, lead and mercury, was an embarrassment for the U.S. Environmental Protection Agency.
