SANDPOINT — Conservation groups are threatening to sue the owners of the Troy Mine over continuing water pollution seeping from the Troy Mine in northwestern Montana.

The groups, citing the Montana Department of Environmental Quality, contend the copper and silver mine, which has been closed since 2015, contributes toxic mining pollution at a rate of hundreds of gallons per minute to Lake Creek.

The Western Environmental Law Center, on behalf of the Montana Environmental Information Center, filed notice in Helena of its intent to sue Helca Mining Co. over the pollution. The notice was filed on Nov. 29.

The Montana Department of Environmental Quality has designated Lake Creek as “impaired,” meaning it fails to meet water quality standards due to pollution from nitrate, copper, lead and sediment due to its proximity to the mine’s tailings impoundment area.

“During mining operations several tons of slurried tailings were dumped daily into a 430-acre tailings impoundment located adjacent to Lake Creek. The impoundment is unlined,” the Western Environmental Law Center said in the notice.

The substances the mine and tailings impoundment are discharging include, but are not limited to, nitrite plus nitrate, copper, zinc, antimony, arsenic, lead, cadmium, uranium, iron, manganese, and dissolved solids. Sampling upstream of the tailings facility did not find concentrations of lead or copper above non-detectable levels, although WELC notes that Montana DEQ has not required Hecla to treat the pollution.

“Polluted water has seeped from the unlined tailings impoundment at the Troy Mine into Lake Creek every day for the last five years, and every day for many years before that,” said Andrew Hawley with the Western Environmental Law Center. “If DEQ would do its job, we wouldn’t have to go to court to force action on this obvious source of illegal pollution, but here we are.”

Jim Jensen of the Montana Environmental Information Center said MDEQ is giving the mining industry a free pass, while leaving the public to deal longterm pollution.

“Because of this regulatory failure, MEIC is once more forced to step forward to defend the public’s right to a clean and healthful environment and unpolluted waters,” Jensen said.

Hecla spokesman Luke Malek said the company disagrees with the allegations.

“The Troy Mine is in compliance with its permits and we take compliance seriously,” Russel said.

Russell said the allegations date back to 2005, 10 years before Hecla purchased the mine and noted that the claims had never been raised before. He added that point illustrates that the claimants are serial litigants who seek to prevent responsible economic development in northwester Montana.

Keith Kinnaird can be reached by email at kkinnaird@bonnercountydailybee.com and follow him on Twitter @KeithDailyBee.