Gold exploration work at Keystone causes illegal leak into Battle Creek
December 01, 2012 6:30 am • Kevin Woster Journal staff
State environmental officials are investigating an illegal leak into Battle Creek in Keystone caused by gold-exploration work by a Canadian mining company.
The leak, a violation under state environmental law, developed Thursday, allowing bentonite — a clay material used in the process of drilling exploration wells — to seep into the creek along Highway 40 near the southeast edge of town.
The crew working at the nearby drill site stopped drill work and reported the leak to the state Department of Environment and Natural Resources, which oversees the gold exploration work that began in the Keystone area earlier this fall. The leak soon began to dry up, DENR engineering manager Mike Cepak of Pierre said Friday.
"Two hours after they stopped drilling that flow had essentially stopped," Cepak said. "Until they figure out what was causing they leak, they won't be drilling, at least in that area."
Cepak said it was too soon to say whether there would be a penalty for the mining company, Mineral Mountain Resources Ltd., of Vancouver, British Columbia. He said DENR would determine whether a clean-up effort was necessary, since the spill was relatively small and the material not considered hazardous.
Cepak said it's unlikely there will be serious environmental impacts to the stream, which is classified as a cold-water fishery and supports trout in some reaches.
"It's a bentonite clay with a little quartz that they use in drilling for lubrication and sealing cracks," he said. "It's milky in color and texture and looks out of place, but it's basically benign. But it's still a discharge that they shouldn't have done."
DENR officials were at the creek Friday to look at the leak and take water samples.
Contacted by email on Friday afternoon, Mineral Mountain Resources spokesman Brad Baker said he was away from the office and wouldn't be able to comment on the leak until next week.
Stan Michals, energy and minerals coordinator for the state Game, Fish & Parks Department in Rapid City, said he didn't expect the leak to cause major damage to the stream or its fish life.
"If this was a more harmful substance, we would have gotten involved," Michals said. "It's a pretty straightforward thing, probably more unsightly than anything."
Cepak said Mineral Mountain Resources had drilled eight to 10 new exploration holes in the area under exploration permits with DENR. He said the crew was working on a steep hillside about 200 feet away and 50 higher than the creek. It's a previously mined area with broken rock that could have allowed the leak to reach the creek, Cepak said.
The spill occurred the day after Mineral Mountain Resources released initial results of its exploration work in the area. Company officials were pleased with what they have found so far, company President and CEO Nelson W. Baker said in a news release.
"Not only did the drilling demonstrate robust grades and widths potentially amenable to underground mining methods, but more importantly the exceptional exploration potential of the entire gold system in the Keystone area which we have just begun to explore," Baker said.
Mineral Mountain officials have said the area seems well suited for an underground mining operation.