Finds may extend life of mine by 5-10 years

MISSOULA – An exploration project at the Troy Mine Complex in northwest Montana could extend the projected six- to seven-year life of the mine by another five to 10 years, officials with Revett Minerals say.

Early testing suggests the copper and silver ore reserves are a higher grade than the ones Revett is currently mining and milling, said Doug Ward, vice president of corporate development at Revett.

The resources are about 1,000 feet deeper in the earth.

“It’s still very early, and we have to drill enough holes to connect the dots,” Ward told the Missoulian newspaper, which reported on the mine’s future prospects in Saturday’s editions.

Ward said the mine employs 165 people whose jobs could be extended if the exploration program is successful. About 15 more test holes will be drilled.

He added it is unclear yet whether new permits would be required to mine the additional copper and silver.

Asarco, the prior operator at the Troy Mine, drilled a number of holes and estimated there were 11 million tons of resource south of the mine, Ward said, “and if it continues under the mine and this proves up underneath, there could be three or four times that.”

Ward said a “ballpark” figure was that the unmined resource would deliver half copper and half silver.

Copper was selling for about $1 a pound, and silver for $4 an ounce, when the mine was shut down in 1993, Ward said.

“They were still making money on the mine, but just barely,” he said. The company opted to leave minerals in the ground so that a future buyer could pay reclamation costs.

Revett bought the mine in 1999 and prices rose high enough for the company to reopen operations in 2004. Since then, prices have gone even higher – $2.50 a pound for copper and $13 an ounce for silver – to make it feasible to explore extending the mine’s life, Ward said.

Since the company purchased the mine from Asarco in 1999, state regulators have increased the cleanup bond from $2.8 million to $12.3 million. The company has posted that bond, and has invested $7 million into an interest-bearing account to cover future cleanup costs.

But Revett and the state of Montana have squabbled over whether the company needs to pay for an environmental impact statement before Department of Environmental Quality regulators can approve a final reclamation plan for the mine.

DEQ says it must. Operators argue that if the mining changes substantially, an EIS on the current operations would be premature. Recently the company offered to pay for a scaled-back environmental assessment, but state regulators have not ruled on whether that would be adequate.

Environmentalists have sued the state in an attempt to force – and hasten – the EIS process.