A million gallons of polluted water flowing down the Animas River started as a small trickle.
The entrance to the Gold King Mine has long been collapsed, and the Environmental Protection Agency planned to clear the dirt blocking the tunnel to install a pipe to pump out the contaminated water in the mine, said Hays Griswold, on-scene coordinator for the agency.
Once the water was pumped out, the crew planned to plug the mine to prevent more polluted water from draining out of the mine.
“We were being very, very careful,” he said.
His team of three workers were using a track hoe and other heavy equipment to clear dirt from in front of the mine, he said.
He believed the water to be only about 5 feet high behind the dirt, and he noticed water seeping from below the dirt in the tunnel of the abandoned mine.
After his team had cleared a 10-foot-tall hole in the tunnel, Griswold walked into it to check if the roof was safe. That’s when he noticed a small stream of water coming from the top of the dirt wall.
At first, he thought it was a natural spring. But the flow started to slowly increase and erode the dirt blocking the tunnel.
“There was more water under pressure than we realized,” he said.
That’s when he decided to get out of the way.
“There was no stopping it at any time,” he said.
Downstream, Durango resident Lisa Shaefer said she was near the mine at Gladstone on Wednesday when a wall of water from the mine carrying rocks and debris roared past.
“What came down was the filthiest yellow-mustard water you’ve ever seen,” she said.
The water was about 12 feet high behind the dirt blockage and it likely carries iron and zinc, Griswold said.
But he was unable to say exactly what metals were in the water, because testing has not been completed.
As of Thursday afternoon, the mine continued to drain 1,200 gallons of polluted water per minute, he said. The team plans to install a water-treatment system and plug the mine to stop the pollution.
Given the high level of water in the mine, it is likely a flood of pollution from the mine would have broken through the dirt at some point, he said.
But his team intended to prevent a blowout like this from happening.
The EPA is also working to clear out the entrance to the Red and Bonita Mine, another leaking mine, and plug it with a concrete bulkhead. But the work has not yet been completed, so it did not contribute to the buildup of water in the Gold King Mine, he said.
Work at the Gold King will continue under a different on-scene coordinator, because Griswold was filling in this week for the long-term coordinator who was on vacation.
San Juan Corps, the company that owns the mine, issued a statement about the accident, holding the EPA responsible.
“Upon suspending work last year, the (EPA) backfilled the portal to the mine. While the USEPA was removing the backfill from the portal to the Gold King Mine to continue its investigation this year, the plug blew out releasing contaminated water behind the backfill into the Animas River,” said Nancy Agro, the company’s attorney in the statement.