EPA says it underestimated mine waste blowout risk

Workers with the Environmental Protection Agency (EPA) underestimated the risks of the mine waste spill this month in Colorado, the agency said.

The Wednesday report is the first extensive analysis of how the EPA allowed 3 million gallons of poisonous mine waste sludge with heavy metals to flow into a tributary of the Animas River near Silverton, turning it bright orange and closing it for more than a week.

{mosads}The EPA and Colorado’s mining agency knew there was likely some fluid behind a part of the mine that had been filled in with rock, where workers were exploring.

But the agencies’ extensive analyses found that the water pressure was low, leading them to not take precautions or preparations for a high-pressure blowout.

“Despite the available information suggesting low water pressure behind the debris at the Adit entrance, there was, in fact, sufficiently high pressure to cause the blowout,” the internal report states. An adit is an access path into a mine.

“Because the pressure of the water in the Adit was higher than anticipated, the precautions that were part of the work plan turned out to be insufficient.”

It is unclear whether additional steps could have prevented the blowout and its effects.

The investigation team concluded that the underestimation of pressure “is believed to be the most significant factor relating to the blowout.”

It also concluded that the high-pressure blowout was “likely inevitable.”

Investigators identified one test that could have determined the true pressure behind the filled-in mine section: drilling a hole from above the mine in a spot further back from the entrance.

But since every indication showed that there was no risk of the higher pressure, the agencies had no reason to conduct such an expensive, difficult task.

The EPA has taken full responsibility for the spill at the abandoned Gold King Mine.

The internal report released Wednesday concludes only the first investigation of the incident. The EPA’s inspector general and the Bureau of Reclamation are conducting their own inquiries, as is the House Science Committee and others on Capitol Hill.

The day before the report was released, Senate Science Committee Chairman Lamar Smith (R-Tenn.) said the EPA has neglected its responsibilities to be transparent in its response to the spill.

Smith said the EPA had not provided his committee with the documents it requested in the timeframe it had set.