EPA completes effort to contain toxic runoff from abandoned mine near Keystone
For decades, drainage from the toxic Jumbo Mine leaked dissolved cadmium, copper, lead and zinc into Summit County waterways. But thanks to a federal cleanup operation completed in October, one major contributor of metal contamination in the Snake River watershed is contained.
Jumbo Mine sits a couple hundred yards above a portion of Peru Creek that is so metal-contaminated it’s considered a “dead zone” because it’s unable to sustain life. Peru Creek flows into the Snake River 2 miles downstream, which in turn travels 10 miles before reaching the Dillon Reservoir, the main source of drinking water for Denver and its 1.4 million residents. According to the U.S. Environmental Protection Agency notice for the Jumbo Mine, the site was listed as a “Priority One” project for remediation. The escalation in priority came after lobbying from Snake River Task Force and other local stakeholders. The Colorado Department of Public Health and Environment listed Jumbo as a “significant” contributor of water degradation in the area.
Cleaning these contaminated sites is a major challenge for Summit County, as an entire bureaucratic process needs to take place before cleanup can even begin. Brian Lorch, director of Summit’s Open Space & Trails department, said the county has been trying to buy up many of these sites for clean-up purposes, but faces an uphill battle.
“There are thousands of these tiny claims and abandoned mine areas across the mountains,” Lorch says, “and each one poses unique challenges and issues that we have to deal with.”
The county, working with state and federal authorities, has identified sites in urgent need of decontamination and has used several land purchase strategies to safeguard the areas, as well as create more protected open space. Jumbo is an example of a private-public partnership in which both the government and private landowner worked together to repair the area.
On Wednesday afternoon, Lorch provided a tour of the site, pointing to what seemed to be huge snowy mounds rising above the path. These, he says, are tailings, or huge waste piles of rocks that were dug out and left outside the mine entrance when it was active from 1915 to 1918. Those piles are the primary problem at Jumbo and many other mines like it, dotting the mountainsides and valleys and poisoning the water.
Duane Newell, the EPA coordinator overseeing the Jumbo cleanup, said the problem lies with acidic water draining out of Jumbo since the mine opening collapsed in the ’60s. He explains that acidic water has been flowing out at rates of 30 to 100 gallons per minute, and some of that winds up flowing through the tailings.
“That acidic water was running across the waste rock pile, which is approximately 25,000 cubic yards,” Newell explains. “That acidic drainage leached these metals and other solid material and transported them down into Peru Creek.”
Newell says the problem was resolved by diverting water flow around the contaminated waste piles, using a durable “vapor” barrier liner to keep the water off the tailings, and then using limestone on top of that to neutralize the water acidity.
For now, the most significant issue with Jumbo is resolved, but other concerns, such as capping the tailings and acidic water flowing out of the mine, also need to be addressed.
Newell said that the funding is not there to address that quite yet, but the site is relatively stable for the moment.
Without intervention, the Jumbo site would have continued to contaminate the watershed. Newell notes that while Jumbo was a significant polluter, it is just one of many sources of contamination for Snake River. In 2013, the EPA began major clean-up operations a few miles away at the Pennsylvania Mine, considered one of the most polluted mines in Colorado and the single largest polluter of Peru Creek.
As mining’s legacy continues to have consequences for the Snake River watershed and the county as a whole, Newell said the collaborative efforts of local stakeholders and government agencies such as the EPA are slowly but surely chipping away at the problem, and hopefully one day Peru Creek will be clean enough to support aquatic life again.
“It has been getting better over the years, definitely,” he said.
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