Epa May Relax Mine Waste Limits

Silver Valley mining companies complained loudly last year when the Environmental Protection Agency proposed strict limits on metals released into the Coeur d’Alene River.

The agency said last fall that it would work with the companies as much as possible, and try to accommodate their concerns.

EPA officials said at Tuesday’s meeting of the Coeur d’Alene River Basin Commission that the agency probably will relax some limits, called Total Maximum Daily Loads, or TMDLs.

The change stems from studies that show the water hardness in the South Fork of the Coeur d’Alene River varies with the river’s seasonal flows: the hardness of the water - the mineral load it carries - rises as the flows dwindle.

Metals become less toxic in harder water, so the EPA can back off metals limits during low and average flows, said EPA’s Ben Cope.

EPA apparently can allow the mines to have “significantly higher” lead, zinc and cadmium emissions at lower flows, Cope predicted.

The TMDL won’t be final for another two months.

Mining companies celebrated cautiously, because higher flows occur roughly six months a year, an industry spokeswoman said.

“It is good news for the companies,” said Holly Houston, of the Mining Information Office in Coeur d’Alene. “But they are still concerned … half the year they’re still going to have stringent limits.”

State officials announced more good news: reversing earlier projections, it appears the Bunker Hill treatment plant can meet the new limits with an upgrade.

Wastewater treatment plants in the valley, however, still will have trouble, said Geoff Harvey, of the Idaho Division of Environmental Quality.

The plants will need some kind of relief from EPA, such as a wastewater permit variance.

Federal officials say they also tried to address widespread Silver Valley concerns over naturally occurring levels of lead in the mining district.

National standards for the toxic metal don’t apply here because there’s so much lead coming out of the ground, argued people who sent hundreds of comments to EPA last year.

But a new study backs EPA findings that lead occurs naturally at relatively low levels, far below the national water quality standards.

The agency initially found low background levels at one testing site, high up the Coeur d’Alene watershed above the influence of mining activities.

But the new study, conducted for the federal government and Coeur d’Alene Tribe’s Natural Resource Damages Assessment lawsuit against the mines, looked at 43 sites, Cope said.

The study looked mostly at surface water in mineralized areas, and found “very low” background levels, he said.

The mines are skeptical of the data because it’s associated with the lawsuit.