Snake River Watershed Task Force hears Pennsylvania Mine update
February 13, 2014
One of Summit County's most polluted watersheds is undergoing a makeover with the goal of reducing heavy metal flows from the Pennsylvania Mine into Peru Creek and the Snake River near Keystone.
The Pennsylvania Mine was identified years ago as the primary man-made source of heavy metal contamination — namely dissolved zinc — in Peru Creek, which feeds into the Snake River, said Peter Graves, senior project manager and geological engineer with the Colorado Department of Natural Resources, Division of Reclamation, Mining and Safety.
Although not a primary health risk for humans, dissolved zinc makes it difficult for fish to exchange oxygen, or breathe. Currently, water flowing out of Pennsylvania Mine contains zinc levels ranging between 80 to 140 parts per million, which has decimated trout numbers to zero in Peru Creek and certain sections of the Snake River.
Last May, Graves and several other environmental stakeholders, including the U.S. Environmental Protection Agency, launched the first of a series of projects aimed at drastically reducing contaminated water flows out of the mine. On Wednesday, Feb. 12 those stakeholders provided a project update during a Snake River Watershed Task Force meeting in Keystone.
“The amount of water flowing into Peru Creek isn’t going to change, but by dispersing it over a larger area it is going to be of significantly better quality. The term we like to use is ‘pre-mining conditions,’ which means the goal is to return water quality to levels before mining operations occurred there.”
Senior project manager and geological engineer
Graves, who has been tasked with addressing issues inside the mine itself, said the ultimate goal is to install two bulkheads to prevent contaminated water from flowing into Peru Creek. However, the mine has not been active since the 1930s, which forced Graves and his crew to focus on infrastructure improvements inside the mine to improve safety before the bulkheads are constructed.
Bulkheads essentially are giant concrete corks, Graves said, and workers have identified two sources of contaminated water inside two of the mine's six drifts, or tunnels. Because oxygen plays a significant role in the contamination level of water flowing out of the mine, Graves said the strategy is to construct the bulkheads to backfill water into the mine, thus reducing the amount of oxygen it contains.
The water, which will already be cleaner than what is currently flowing out of the mine, is then dispersed over a larger area to allow nature to naturally remediate the dissolved zinc out the water before it flows into Peru Creek, Graves said.
"The amount of water flowing into Peru Creek isn't going to change, but by dispersing it over a larger area it is going to be of significantly better quality," Graves said. "The term we like to use is 'pre-mining conditions,' which means the goal is to return water quality to levels before mining operations occurred there."
Currently, water flowing out of Pennsylvania Mine contains a Ph level of about 3.5 to 4. Although a neutral Ph level is 7, Graves said streams, rivers and rain water are naturally acidic, meaning a healthy stream might feature a Ph level of about 6.5.
Crews plan to return to the Pennsylvania Mine site this summer and one of the primary goals on their 2014 agenda is to determine a location for, finalize the design of and construct the first bulkhead.
Paul Peronard, federal on-scene coordinator for the EPA, anticipates that by 2015 there will be a need for a second bulkhead. The bulkhead planned for this coming summer is estimated to cost about $500,000.
Peronard said federal funding is available for the second bulkhead, but government funds are not a guarantee.