Nearly a month after falling rock forced Revett Minerals, Inc. to cease underground operations near Troy, the Lincoln County copper and silver mine remains closed. CEO and President John Shanahan said unstable ground conditions and a recent earthquake have kept the mine from reopening as planned.
“I think we’ll be back up and running again soon,” he said. “We’re all looking forward to getting back to work.”
On Dec. 1, company officials decided to stop all underground mining after a series of rockslides inside abandoned parts of the mine. Shanahan said rain throughout November and freezing temperatures in December are part of what led to the unstable conditions. Because of that, the rock inside the mine began to fracture and crack. A small earthquake on Dec. 20 followed the unstable ground conditions.
On that day, the United States Geological Survey reported a 3.1 magnitude earthquake 29 kilometers southwest of Libby. The epicenter was less than a mile beneath the surface.
“Given the activity we saw in December, we decided we should install (geophone) monitors,” Shanahan said.
Shanahan said the geophones can gather data about how much the ground moves and can recognize anything from a truck driving by to an earthquake. He said this was the first time any such equipment has been put in the mine and hopes to complete the installation by the middle of January.
Since the Dec. 1 closure, Revett has monitored conditions underground. Even if no one is deep beneath the Cabinet Mountains looking for silver and copper, Shanahan said all 205 employees are working, mostly on above ground maintenance and cleanup projects. Shanahan said no one has been laid off because he remains hopeful that the mine closure is temporary.
The closure has not only slowed production, but also slowed Revett’s plans to announce projections for 2013. Shanahan had hoped to announce the production numbers in mid-December, but that will likely not happen until the mine reopens.
The December slowdown put a significant dent in the mine’s projected copper and silver production numbers for 2012. As of Nov. 30, the Troy Mine had shipped 1.1 million ounces of silver and 7.5 million pounds of copper. In May, the company announced plans to produce 1.4 million ounces of silver and 11.5 million pounds of copper.
Shanahan said it was still too early to know how the shutdown would affect the coming year, but added that safety is his primary concern. Revett plans to work with the Mine Safety and Health Administration to determine when the Troy Mine will reopen. He said ground conditions are slowly getting better and was hopeful that operations could start back up sometime in January. However, he was hesitant to give an exact date.
“It’s mining,” he said. “And mining has a way of throwing curve balls at you.”