Ten miles north of Silverton, in a remote area known as Gladstone, more than 36 inches of snow covers the ground where the Environmental Protection Agency’s new water treatment plant operates even in below-zero temperatures and seemingly endless snowfall.

Freddie Canfield, Silverton’s weather guru, said temperatures dropped to 22.8 degrees below zero on New Year’s Day, and it’s likely that in Gladstone, which is higher in elevation, it was even colder.

“When you go outside and your beard and your mustache are flash frozen, you know it’s 20 below,” Canfield said.

Which begs the question: How does the new water treatment plant hold up in such an extreme and isolated environment?

On Sept. 23, the EPA announced it would build a temporary water treatment system. That came seven weeks after an agency-contracted company triggered the Gold King Mine blowout, releasing 3 million gallons of heavy-metal laden sludge into the Animas and San Juan rivers, affecting three southwestern states.

The $1.5 million plant was finished less than a month later with a system designed to handle up to 1,200 gallons of acid mine drainage per minute. The latest report shows the Gold King Mine is discharging 480 to 510 gallons a minute of wastewater that contains arsenic, lead and cadmium.

As the San Juan Mountains entered the harsh winter months, The Durango Herald looked at how the treatment plant operates during this El Niño winter.

The system

Before the spill, the portal to the Gold King Mine was a flimsy pile of loose dirt and rock that had collapsed on the inactive mine entrance over time. It was that makeshift dam that held back water, and which EPA-contracted crews dug too far into, triggering the blowout.

Workers have stabilized the mine’s entrance and installed a 4,800-foot pipe that runs from the portal of the Gold King Mine down a steep slope into the treatment system at Gladstone. There, the water laced with heavy metals enters settling ponds. Just before the water reaches a reactor, lime is injected, effectively raising the pH level from around 3 and 4 – that of black coffee – to about 7, considered neutral.

The water is then mixed with chemicals that cause clean water to rise and the metal-laden sludge to settle at the bottom of a tank. The clarified water enters a pipe that releases into Cement Creek, a tributary of the Animas River, at a rate of about 450 gallons per minute.

The metal sludge is directed into filter bags adjacent to the treatment plant. A percolated mesh allows clean water to escape while trapping the solid waste. The filter bags last 18 months before they need to be replaced.

Cold not an issue

“Even though there’s snow everywhere, the actual ponds are not frozen over, and the water is flowing freely,” said Laura Jenkins, EPA’s Region 8 media officer. “Everything continues to operate despite the extreme cold.”

Jenkins said temperatures dipped as low as 18 below zero in Gladstone, and the federal agency was prepared to fill the settling ponds to capacity to let water flow underneath the ice cap and into the treatment facility.

But that wasn’t necessary, she said, because water discharges out of the mine at a temperature of about 50 degrees. By the time it hits the settling ponds, the water is still above freezing.

“The water coming out of the mine is basically groundwater, so it has a higher temperature,” said Peter Butler, coordinator of the Animas River Stakeholders Group. “As long as you keep it moving, it probably won’t freeze.”

Butler said winter is usually the most important time to treat mine wastewater because that is when metal concentrations in the river are the highest. There’s more snowpack, which means less running water, and less dilution in the waterway.

“Whatever is in rivers and streams (in winter) is groundwater, and there’s not a lot of it,” Butler said. “And if it’s coming out of a mine portal, it’s not going to be good quality.”

Remote location

Gladstone is accessed by an unpaved county road, now regularly covered with snow. But EPA spokesman Json Marruffo said that hasn’t been a problem since the federal agency hired local plowing crews.

“The road is only cleared up to Gladstone,” he said. “Our understanding is Gladstone will remain accessible throughout the winter, but there may be days where we can’t get through.”

Avalanches could be an issue as winter presses on, Marruffo added. The settling ponds constructed in the immediate aftermath of the Gold King spill were in an avalanche zone, which is why the EPA moved the facility to Gladstone.

Still, the new treatment plant is 600 to 700 feet away from potentially hazardous sloped areas.

“It’s pretty far away,” Marruffo said. “But there’s still some danger there.”

Two local contractors are at the facility on a daily basis, Marruffo said. Should anything go wrong, the EPA has a 24-hour time frame where operators can respond.

The EPA also installed monitoring systems and collects water quality samples that will be compiled, with results expected to be posted in the coming weeks, Jenkins said.

jromeo@durangoherald.com