From the Cañon City Daily Record (Rachel Alexander):
Groundwater near the Schwartzwalder Mine contains uranium levels that are 1,000 times higher than the human health standards, according to an Associated Press article. The contaminated groundwater is near Ralston Creek, which flows into Ralston Resevoir. The resevoir supplies water to Denver and Arvada.
John Hamrick, Cotter’s vice president of milling, said the company had been working with the Department of Reclamation and Mining Safety to address the issue. “We have a plan that is due to them Monday about different remedial alternatives,” Hamrick said. The mine is located north and west of Golden. Hamrick said it started operations in the 1950s and was closed in 2000.
He said there were three parts to the mine when it was in operation: the underground mine, an ore sorter and a water treatment plant for water used in the mining operation. The company has a license through the Colorado Department of Public Health and Environment for the ore sorter and water treatment plant. “We’re in the final process of terminating that license,” he said…
Hamrick said the groundwater flow from the creek goes through waste rock from the mine and that is probably where it is picking up uranium. While the mine itself has water in it, that water level is steady. “We do not think that the mine water is getting into the creek,” he said.
Here’s some history for the mine from Wikipedia:
In 1949 janitor and weekend prospector Fred Schwartzwalder discovered uranium at an abandoned copper prospect in Jefferson County about ten miles northeast of Central City and eight miles north of Golden. The deposit consists of Tertiary hydrothermal veins filling fracture zones oriented predominantly NNW-SSE in gneiss, schist, and quartzite of the Precambrian Idaho Springs Formation. The chief ore mineral is pitchblende, which occurs with adularia and ankerite. Schwartzwalder could interest no one in his discovery, so he drove the first adit of the Schwartzwalder mine by himself, made the first ore shipment in 1953, and sold the mine in 1955. The Schwartzwalder mine was the source of more than 99% of the uranium produced from the Front Range province. The mine operated until 1995, producing 17 million pounds (7700 metric tons) of uranium oxide. The mine is owned by General Atomics subsidiary the Cotter Corporation, which estimates that there are an additional 16 million pounds (7300 metric tons) of uranium oxide resource remaining in the mine.
More coverage from The Denver Post (Bruce Finley):
Uranium concentrations in groundwater 30 feet beneath the brim of the Schwartzwalder Mine exceed the human health standard for uranium by more than 1,000 times, according to state records reviewed Thursday. Unhealthy concentrations also were detected in Ralston Creek, which eventually enters Denver Water’s Ralston Reservoir. The reservoir supplies water to Denver and Arvada.
Denver Water managers say no uranium contamination has entered the drinking-water supply…
Neither Cotter nor the Colorado Department of Public Health and Environment, which is responsible for water quality, notified Denver Water. “It would have been nice to know,” said Brian Good, Denver Water’s manager of operations and maintenance. Denver Water now will increase testing for uranium, Good said, calling on Cotter to clean it up. Because Denver’s Moffat water- treatment plant is closed for maintenance, no Ralston Reservoir water currently enters Denver’s drinking-water system, Good said. “Our water is safe,” he said, “but it’s a little bit troubling that (uranium) is coming into our reservoir in those concentrations.”[...]
Colorado’s Division of Reclamation, Mining and Safety “does not believe conditions requiring an emergency response currently exist. If they should arise, (the state) can require Cotter to pump and treat mine water to bring down levels and ensure groundwater is not jeopardized,” state spokesman Theo Stein said.
From the Associated Press via the Sky-Hi Daily News:
Cotter vice president John Hamrick says they’re considering several methods to deal with the contamination, including creating a wetland.