Toxic Pennsylvania Mine cleanup under way in Summit County
Engineers are ready to tackle Pennsylvania Mine, which has been spewing toxic metals into waterways for over a century.
Pennsylvania Mine bleeds heavy metals, or acid mine drainage, into Peru Creek and the Snake River. The Snake flows into Dillon Reservoir — a major water source for the Front Range.
The mine operated from 1879 through the early 1900s. Like many mines in the area, it sits in a pristine alpine valley. Today the Peru Creek valley, eight miles to the east of Keystone, serves as a year-round destination for recreation.
The mine is one of the largest contributors of human-caused heavy metal in the Snake River Watershed. Contaminants include aluminum, cadmium, copper, iron, lead, manganese and zinc. Exposure to these metals can cause irreversible and lifelong health problems in humans and wildlife.
This summer, the EPA will prep infrastructure to allow heavy equipment into the mine site in hopes of cutting off pollution sources. Meanwhile, the Colorado Division of Reclamation and Mining Safety will continue underground investigations to pinpoint where the toxic metals are originating and decipher which techniques should be used to best clean up the site.
“An amazing amount of investigation has gotten us to where we are today,” Brian Lorch, Summit County director of open space and trails said at a meeting organized by the Snake River Watershed Task Force Wednesday.
EPA on-scene coordinator Paul Peronard expects the mine cleanup project to take place over three years, and cost about $3 million. Progress will be made in “finite, bite-size chunks,” he said.
An investigation led by senior project manager Jeff Graves set the stage for the upcoming cleanup project. Until recently, portals were collapsed at the mine entrance.
“There was no way to determine how the water flowed from the mine workings and became contaminated,” Graves said.
Workers drilled holes into the ground and used a borehole camera to inspect the inside of the mine. The state-of-the-art technology was combined with maps from the 1920s to create a blueprint of the mine site.
“We had a pretty good feeling if we were able to open the portal we could get access and do some underground work in the mine,” Graves said.
Stakeholders then came up with a portal rehabilitation project. They dug and cut their way into the mine and installed very large culverts into two mine portals.
The work required climbing through “hobbit holes” and dealing with 2 feet of muck, but it allowed researchers to get data about the amount of flow and level of contaminants coming through the F and C portals of the mine — where the bulk of the cleanup work will be done.
The water found was “pretty nasty stuff.” The substance was a rusty orange color — very similar to the hue of the excavators on site.
Geologists and engineers used dye to track water flows, created settlement ponds and revegetated disturbed areas.
In June, workers will prepare the mine site and stabilize the portals so more detailed underground investigations can be made.
Geological engineer Graves’ plan is to install inner and outer bulkheads at the mine. The problem workers have with sealing waterways is a lack of rock and other landmass on top of the mine to contain underground water pressure, he said.
“We may also be able to catch water higher up in the mine and remove it before it goes through more contaminated parts of the mine,” Graves said.
In addition to installing bulkheads in 2014 and 2015, stakeholders plan to cap waste and tailing piles in place with topsoil and vegetation to prevent erosion and contaminants from leaching. Any significant surface water pathways discovered during the underground investigations will also be sealed.
“I’d like to get those stream flows off the waste pile and into a more natural setting,” Peronard said.
Once the cleanup is complete, Peronard said the EPA would like to hand off maintenance to a local management group. Although it’s hard to talk specifics at this point, he said, the idea would be to determine what long-term maintenance would entail and come up with funding to carry out the work.
The long-awaited Pennsylvania Mine cleanup follows a series of mine projects undertaken by The Snake River Watershed Taskforce. Entities involved include Summit County government, the U.S. Forest Service, the Colorado Division of Reclamation Mining and Safety, the Blue River Watershed Group and the EPA.
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