Boise headwaters mining exploration put on hold because of water pollution concerns

The proposed CuMo molybdenum mine site. (Photo by Greg Stahl)

In a lawsuit brought by Idaho Rivers United and partner organizations a U.S. District Judge ruled on Aug. 29 that mining exploration in the Boise River headwaters could significantly impact water quality in the area.

U.S. District Judge Edward J. Lodge found that the U.S. Forest Service’s actions were “arbitrary and capricious” when it approved the CuMo Exploration Project without examining potential effects to groundwater. He remanded the agency’s environmental document for further study and consideration.

“Water is vital to Idahoans, to water users, irrigators, fish and wildlife, and recreationists,” said IRU Policy Director Kevin Lewis. “The court found that drilling cannot proceed until impacts have been disclosed.”

Mosquito Gold, a Canadian mining company, hopes to build more than 10 miles of temporary roads and 259 drill holes ranging from 1,500 to 3,000 feet deep in the headwaters of the Boise River near Grimes Creek. The drilling is the next step in what the company hopes will become one of the largest open-pit molybdenum mines in the world.

“The very nature of drilling holes 1,500 to 3,000 feet into the ground seems likely to impact the underlying surface including groundwater,” Lodge wrote on page 35 of his ruling. “The appropriate course would be for the Forest Service to have conducted some baseline study and analysis of the groundwater in the area in order to reach the finding of no significant impact.”

Idaho Rivers United, Idaho Conservation League and the Golden Eagle Audubon Society—represented by Advocates for the West and the Western Mining Action Project—filed suit over the concern that drilling in the area could lead to additional pollution.

“The Forest Service acted arbitrarily and capriciously in concluding that no other impacts to groundwater hydrology need be considered,” Lodge wrote.

Further comments from partner organizations follow:

“The big winner here is the Boise River and everyone downstream who appreciates clean water,” said John Robison with the Idaho Conservation League.

“The Court found that the mining company couldn’t just cross its fingers and hope that nothing bad happens,” said Pam Conley of the Golden Eagle Audubon Society.

“I have property below the exploration site so am extremely thankful that the drilling is being put on hold,” said Ann Finley of Boise.

“The court found that protecting Idaho’s groundwater from mining activities is critically important,” said Bryan Hurlbutt with Advocates for the West. “Mosquito Gold must demonstrate that its proposal isn’t going to harm Idaho’s groundwater before it moves forward.”

“This decision will have ramifications throughout the West,” said Roger Flynn with the Western Mining Action Project. “There are exploration projects throughout the region that threaten groundwater and downstream water users. The Court correctly rejected the Forest Service’s practice of ignoring groundwater impacts from mining exploration.”