Gunnison County: Standard Mine cleanup heading into second phase

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From The Crested Butte News (Seth Mensing):

Three representatives from the EPA visited the Crested Butte Town Council and the Gunnison Board of County Commissioners last month to tell them that the second round of remediation work at the site is set to begin this summer.
Gina Andrews, the EPA’s on-scene coordinator for the removal of the mining debris, told both groups that her group’s “task was to remove the waste rock and tailings pond and relocate the pond to a consolidated land fill and cap it off. We finished our portion of that work last fall.”

The council members and commissioners were shown photos of the site before and after the remediation work, which contrasted an abandoned mine—complete with mining cart trestle, a bridge and scattered debris—with a nearly natural high mountain valley.
The 10-acre Standard Mine is located in the Gunnison National Forest and on four patented mining claims on the backside of Mt. Emmons. Mining operations for zinc, lead, silver and gold began on the property in 1931 and continued until 1966, when the mine was abandoned.

In 2005, the property was placed on the National Priorities List for Superfund status, which initiated the EPA to take a series of steps to reclaim the land and treat contaminated water running from the mine into Elk Creek and eventually into the town and county’s watershed. In addition to removing about 50,000 cubic yards of rock waste and pumping the contents of the tailings pond through a filter, Andrews said a fisheries biologist from the U.S. Forest Service helped the team in the relocation of a stream that had been moved to serve the mine…

Andrews said her group would visit the site throughout the summer months to see how the newly constructed streambed holds up to the spring runoff and to monitor the other improvements while making repairs when and where they are needed. Remedial project manager Christina Progess said the next step for the EPA is to do a remedial investigation and feasibility study to get more information about the condition of the site and its effect on human health. The EPA will also be looking at different methods to treat water coming from the mine. One water purification method being tested at the site is a bioreactor that uses microorganisms to “eat” the contaminating heavy metals in the water. The result is water with 96 percent to 99 percent of the heavy metals removed. “The bioreactor is a step in the right direction,” said Progess. “It still doesn’t get us to the state’s stream water standard [for contaminants] but it could be one of several ways we approach the treatment of water coming out of the mine.”

Ground and surface water flows into the mine, where it is contaminated with arsenic, barium, lead, zinc, cadmium, copper and chromium, according to an EPA report that showed those metals at three times their natural level in Elk Creek below the mine site.
The water then flows out of the mine at a rate ranging from ten gallons per minute to 70 gallons per minute during peak runoff. The 40 square foot bioreactor that is now at the site is capable of treating only one gallon of contaminated water per minute. “If water treatment were needed, this system would be scaled out to treat whatever amount of water is coming out of the adit [mine opening],” said Progess. Progess conceded that expanding the bioreactor to treat 70 gallons of water per minute might not be feasible and because the technology is so new there isn’t a lot of data to show the long-term costs of operating and maintaining the reactor on a large scale…

Progess said the EPA would be able to calculate water flows to prepare for all eventualities.The remediation investigation and feasibility study will be done in March 2010, according to Progess, when the EPA will select a final preferred remedy and send out a proposed plan for public review and comment. The process continues with a Record of Decision, published in the federal register; the remedial design and action taking place; and finally completion of construction at the site. Progess said the EPA should hand the project over to the state in 2012. The EPA will then revisit the site every five years to monitor the condition and performance of site improvements. Funding for the project shifts from the EPA to the state, which entered the process early with a 10 percent cost-sharing arrangement. Local governments will not ever be responsible for paying to improve the mine site, said Progess.

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