DENVER – An internal investigation by the Environmental Protection Agency into the Gold King Mine spill found that an “insufficient” analysis of water pressure led to the spill.
Testing the water pressure with proper drilling techniques could have prevented the breach of a dirt wall that caused an estimated 3 million gallons of contaminated wastewater to flood into Cement Creek and down into the Animas River.
The report was released Wednesday, despite a Monday publication date.
Even though a plan outlining reclamation work at the Gold King Mine stated “conditions may exist that could result in a blowout,” an EPA-contracted team failed to properly calculate the water pressure behind a dirt wall that was holding back old mining sludge.
The team was hoping to begin reclamation work, but instead sent the contaminated wastewater from previous mining activities into Cement Creek then to the Animas River on Aug. 5, turning the river a mustard-yellow color and closing water withdrawals to drinking-water systems and the river to recreational use.
“Mine-water pressurization data from behind the blockage potentially could have been obtained through a drill hole inserted further back into the adit from above the mine tunnel,” the report states, pointing out that the drilling would have been costly but valuable. “This procedure may have been able to discover the pressurized conditions that turned out to cause the blowout.”
An adit is a nearly horizontal passage from the surface of 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,” the report continues.
The one-week EPA internal investigation included site visits, interviews and a review of documents related to the project and spill. A separate, independent investigation is underway by the Interior Department, which asked the Bureau of Reclamation to lead the query.
Questions remain, including the level of responsibility placed on the contractor, Missouri-based Environmental Restoration LLC. EPA officials who conducted the internal investigation said Wednesday the report was only preliminary. They say the independent investigation will likely be more detailed about culpability.
The EPA’s internal report stated the team included only “limited emergency procedures in case of a mine blowout.”
“This lack of information about a blowout in the (Emergency Action Plan) could indicate the low expectation of its occurrence by the contractor and reviewers,” it states.
“It was lacking emergency protocols in the case of a significant flow or blowout,” the investigation continues.
EPA Deputy Administrator Stan Meiburg told reporters Wednesday that the agency will incorporate the recommendations in an effort to prevent future blowouts. With thousands of mines leaking across the West, lessons learned could be critical.
“The review team found that provisions for a worst-case scenario were not incorporated into the excavation work plan,” Meiburg said. “That information could have been useful in the case of a significant blowout, like the one that occurred.”
One bright spot, however, is that the site team responded appropriately during and after the blowout by moving personnel and equipment and diverting mine-water discharge, which “probably avoided any fatalities from the pressurized adit blowout.”
Meanwhile, members of Congress are looking to get their own answers. The House Science, Space and Technology Committee hopes to hear from EPA chief Gina McCarthy on Sept. 9 during an official hearing. The incident has offered fodder to Republicans and right-leaning groups who were already at odds with the EPA over carbon-pollution standards and other efforts aimed at slowing climate change.
