A year-long investigation into mercury emissions has led to a state-ordered shutdown of the processing plant of a major gold mine in northeastern Nevada.
Leo Drozdoff, head of the state Division of Environmental Protection, said Wednesday his order requires Queenstake Resources' Jerritt Canyon Mine, about 50 miles north of Elko, to install new, more effective emission-control equipment.
Ore "roasters" which were ordered shut down must be upgraded by the end of the year. If the company wants to restart the roasters earlier, using existing pollution control gear, it must install new instruments to ensure the gear is operating properly.
Drozdoff said the action was taken because of the failure of the company, a subsidiary of British Columbia-based Yukon-Nevada Gold Corp., to fully comply with two previous state orders.
Graham Dickson, head of Yukon-Nevada Gold, issued a statement saying many repairs and alterations had been completed already and it was "unfortunate" that the mine was still "short of the required standard."
Dickson also said the state's stop order is scheduled to take effect March 17 but the roasters already are shut down for planned work. He added the planned shutdown shouldn't affect the expected 2008 production of 120,000 ounces of gold.
When the state first moved against the Jerritt Canyon Mine in February 2007, Queenstake issued a statement saying the company would spend about $500,000 on emission-control upgrades.
The state action was the first under new regulations adopted by Nevada to control airborne mercury emissions at precious-metals mines.
Dr. Glenn Miller, an environmental scientist and Great Basin Resource Watch board member, said the state's action was appropriate but its efforts need to be strengthened to reduce mercury discharge from Nevada mines that has exceeded 100 tons over the last 25 years.
Dan Randolph, executive director of Great Basin Resource Watch, said his group had requested the action last June, adding the mine "clearly has been emitting very large amounts of an extreme neurotoxin for many years and the agency has known about this for quite some time."
The state DEP said the Jerritt Canyon case came to a head in late 2006 when the company conducted tests to meet initial requirements of the new rules.
State inspectors were on hand and saw that dust containing mercury wasn't controlled in the ore-grinding process.
The state DEP's mercury control program was the first program of its sort in the nation. Drozdoff said Wednesday that the program has produced "some early positive results," including moves by two other mining companies to reduce mercury emissions.
Goldcorp, which operates the Marigold mine, installed equipment that showed a dramatic reduction in mercury air emissions, from nearly 900 pounds in 2006 to less than one pound in 2007, Drozdoff said.
He added that Round Mountain Gold Corp., which operates the Smokey Valley mine, installed similar equipment and will report its results soon.