Summit County: Scientists focus on tainted mine runoff
Summit County, CO Colorado
SUMMIT COUNTY, Colorado ” Several weeks of intensive late-summer research at the abandoned Pennsylvania Mine in Summit County, Colorado could help set the stage for state and federal cleanup funds.
About a dozen researchers sampled soils, water and wetlands in September and October, looking for the best ways to treat polluted water at the site. When completed, the results of the studies should help determine the best cleanup options.
“We spent a week … trying to figure out whether the tailings and wetlands contribute pollution to Peru Creek,” said Jean Mackenzie of the U.S. Environmental Protection Agency.
“We also did another round of toxicity tests in the lab. We pulled water out of the creek, took it back to the lab and exposed young trout,” Mackenzie said, explaining that the testing was to determine exactly how poisonous the water is to fish.
Peru Creek has been identified as a priority stream in the state’s cleanup program this year. That means EPA grant funding is within reach, according to Brian Lorch, who directs the Summit County’s open-space program and has led local cleanup efforts at other remediation sites.
The recent testing focused on how the old piles of mine rocks affect water quality, said Mackenzie, who has taken on a lead role in the fieldwork. Among other tools, the scientists used high-tech radar technology to map the plumes of metals spreading from the mine through the soil and groundwater toward the creek.
Other efforts were aimed at understanding how ground and surface water moves through the mine. Shunting clean water around contaminated areas could reduce the amount of treatment needed, Mackenzie said.
That’s where the EPA funding could be useful. Treating water flowing out of the mine is legally challenging because of liability issues associated with the federal Clean Water Act. Taking more simple steps first could be quicker and more cost-effective, she said.
“We are trying to look at the site holistically. There are all these other sources (besides the mine itself),” she said.
Another option recently placed on the table is a Superfund designation for the Pennsylvania Mine. Although there is an environmental stigma attached to the designation, it could help bring significant resources into play, according to Mackenzie.
“The EPA is looking pretty strongly at a Superfund listing,” Lorch said. “It’s a bit of a concern to various parties.”
n is clean? What’s the goal here?” he concluded.
The old mine, high in the Snake River Basin, yielded prodigious amounts of gold, copper, lead, zinc and especially silver in the late 1800s and continued to operate until 1940, even after a big avalanche wiped out several structures in 1898. In 1893, the mine shipped 7,000 tons of silver. Between 1893 and 1898, production at the mine exceeded $3 million.
More recently, the mine has posed a vexing problem for engineers and biologists seeking to clean up toxic heavy metal pollution in the Snake River. When mining ceased, a toxic brew of metals continued oozing from old mine openings, tainting Peru Creek and the Snake River, far downstream.
To this day, levels of some metals, especially zinc, remain well above state-set limits. The concentrations are high enough to kill trout several miles downstream in the Snake River, nearly all the way to Dillon Reservoir.
State experts explored a cleanup plan in the late 1980s, even building artificial wetlands and a passive treatment system designed to neutralize the acidic water draining from old mine tunnels.
But they underestimated the amount of treatment needed, eventually abandoning the project.
Those wetlands, built upon huge piles of tainted rocks chiseled out of the mountain, were the focal point for the recent tests.
Ten years later, the U.S. Forest Service helped cobble together the Snake River task force, a collaborative group including private, local, state and federal stakeholders.
The overall goal remains the same: improving water quality in the Snake River to the point that trout can re-establish self-sustaining populations.
Part of the reason for the renewed effort is related to the recreational and biological values associated with the Snake River.
While the water doesn’t pose any serious threat to human health, it’s used for snowmaking at Keystone. At one point, a federal study showed elevated levels of metals in the man-made snowpack at the ski area.
With an overall water shortage in Summit County, any additional sources of pure water would be welcome.
From an EPA standpoint, the ultimate goal would be to restore water quality to a level that could support native fish species. For Peru Creek, that would be cutthroat trout.
But realistically, that’s not going to happen. Even if all human-caused sources of pollution are removed, the high level of naturally occurring metals in the drainage would be too high.
Part of the research is to establish a realistic cleanup level, Lorch said.
Based on the research to date, cleaning the river to a point of being able to sustain rainbow trout is achievable, he said.
A lot of the research that’s been done over the years is background. The latest studies should help find a fix, Lorch said.
“We need to know, how clean is clean? What’s the goal here?” he concluded.