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Commissioners oppose plan to remove impoundment dam

by DERRICK PERKINS
Daily Inter Lake | October 2, 2020 7:00 AM

Worried that a forthcoming permanent remedy for the former W.R. Grace mine site might include removing the Rainy Creek impoundment dam, county officials revealed an alternative plan on Sept. 30.

Detailed in a letter signed by Lincoln County commissioners Mark Peck (D-1), Jerry Bennett (D-2) and Josh Letcher, the proposal calls for maintaining the existing impoundment dam, limiting onsite construction activity and creating an interagency fire response plan, among other stipulations.

The letter also calls for any natural resource damage dollars recovered from Grace stay in Lincoln County. That money “should be used within the Libby area and Lincoln County to enhance forest health, recreation, water quality and economic benefit to the local area,” the document reads.

Peck said officials with the state Department of Environmental Quality were pushing to replace the impoundment dam, which holds back mine tailings, with three other structures nearer to the top of Vermiculite Mountain.

“It just makes absolutely no sense to me for a couple of different reasons,” Peck said. “Right now that dam acts as filtration directly to the river. If we remove that, we expose the river to all of that material that will be up there in the drainage.”

Bennett worried that construction work, both to demolish the existing dam and build new structures, could send more contaminated material up into the air.

“We spent one whole summer just moving material for that dam,” he recalled. “You start excavating that and you’re throwing that to the wind, for [lack of a] better term.”

Both raised concerns that removal of the dam would lead to erosion and, eventually, contaminated material flowing into the Kootenai River.

“Can you imagine, without the dam there, the potential, year after year, of it eroding down into drainage,” Bennett said. “You don’t need a degree to figure that one out.”

Lincoln County has no direct say in how the mine site, known as Operable Unit 3, will be remedied. Negotiations there are between DEQ and the EPA, Peck said. W.R. Grace, because it retains ownership of the site, remains the responsible party.

But Peck expressed hope the letter will dissuade state and federal officials from doing away with the existing impoundment dam. Commissioners addressed the missive to Shaun McGrath, DEQ head, and Gregory Sopkin, regional administrator for the EPA. They also plan to send it to Montana’s congressional delegation.

“I still wanted to get on record … our input on what we would like to see up there as a county,” Peck said. “Just removing the dam itself would be unbelievable.”

The mine currently is undergoing renovation and repair work, to the tune of between $50 and $100 million. Grace, which has undertaken the effort, finished work on a cofferdam at the site in August. Designed to withstand a 500-year flood, the cofferdam will let workers begin replacing a spillway.

The project is expected to take several years to complete.

Peck said that if the EPA and DEQ reach an agreement and it includes demolishing the impoundment dam, it could be demolished in the near future.

“The timeline is fairly quick,” Peck said.

Commissioners also called on the two agencies to manage timber and vegetation within Operable Unit 3 to limit fire risk and protect the future remedy. As well, they want a public outreach and education plan in place to promote understanding of the risks associated with recreating near the former mine.

Bennett made the motion to send the letter to the DEQ and EPA. Peck seconded it. County Commissioner Josh Letcher (D-3) was not in attendance, but previously signed the document.

The motion passed unanimously.