EPA tackles water threat from blocked tunnel in mining town
February 15, 2008
DENVER – Federal officials plan to pump from the water table near a blocked mine drainage tunnel to ease pressure from more than a billion gallons of trapped water that locals fear could cascade through the historic mining town of Leadville.Pumps will be installed at an abandoned mine shaft next week, Lake County Commissioner Carl Schaefer said Friday.The move will give federal officials time to work on a plan to drill into the damaged tunnel, then pump backed-up contaminated water to a treatment plant. Work on the project could begin as early as this spring, said Peter Soeth of the Bureau of Reclamation, which owns the tunnel.Federal, state and county officials agreed to the plan, designed to ease water pressure caused by a partial collapse of the 2.1-mile tunnel. The tunnel normally drains water that seeps into some of the hundreds of mine shafts and other mine workings in the mountains east of Leadville and deposits it into the East Fork of the Arkansas River about a mile north of town.The Environmental Protection Agency, which would pump the water, said it wasn’t sure that the pumping would effect water inside the tunnel but could reduce nearby seepages. The area is laced with abandoned mine shafts, and the EPA operates a Superfund cleanup site south of mine shafts drained by the tunnel.Lake County declared a state of emergency Wednesday out of fear that this winter’s above-average snowpack could cause a catastrophic blowout of water.But the federal Bureau of Reclamation, which acquired the tunnel 1959, says its data indicates there is no imminent danger of a blowout. It’s examining the blockage, and a draft of its report is expected in July.Gov. Bill Ritter sent a letter to President Bush asking for quick action, and members of Colorado’s congressional delegation have expressed concern for the town’s 2,700 residents.A plan to pump water out of the tunnel, developed by the EPA in 2004, would cost at least $4.5 million. It calls for permanently capping the tunnel, drilling a shaft into it and pumping the water to the Bureau of Reclamation treatment plant at the tunnel’s mouth.County officials have been concerned about water backing up in the shafts for several years, but the issue became mired in discussions before the county declared its emergency.”We’ll start working on it rather than just studying it,” said Schaefer.Water seeping from the mine shafts is contaminated with zinc, cadmium, manganese and other heavy metals that must be removed before it is pumped into the Arkansas River.In addition to a possible threat to Leadville’s 2,700 residents, a blowout could send the contaminants into the river. A speaker system to broadcast evacuation notices has been installed near a mobile home park located by the mouth of the tunnel.Local and federal officials are unable to agree on the source of the rising water.”We don’t know where water is in the rock,” Soeth said. “It could be in fissures. It could be in old mining tunnels. They’re numerous, intersecting. We’ve had a record snow year, so water is coming in.”Jeffrey Foley, Lake County’s emergency management director, said county studies indicate the blocked tunnel has allowed the water in the surrounding mining pool to build and seep into nearby California Gulch, where the EPA operates its Superfund site. That gulch sits south of the tunnel.EPA spokeswoman Sonya Pennock said the agency has documented an overall rise in the area’s water table that may be unrelated to the tunnel collapse and rising mine pool. EPA officials also believe that water appears to be seeping into the tunnel from Evans Gulch, to the north.Starting next week, water pumped from the abandoned mine shaft will be sent untreated into a gulch that flows into the Arkansas River.Leadville, elevation 10,200 feet, attracted thousands of people during an 1859 gold rush. When the gold ran out, silver mining became the dominant industry.Leadville’s Climax mine began shipping molybdenum ore in 1915. Miners have recovered 946,000 tons of molybdenum, used to harden steel, worth about $4 billion. The Climax mine closed in 1995, though Freeport-McMoRan Copper & Gold Inc. plans to reopen it next year.