CuMo mine exploration would have no major environmental effects, Boise National Forest finds

The CuMo Exploration Project aims to search for minerals that could lead to a mine years later in mountains outside Boise. (Kyle Pfannenstiel/Idaho Capital Sun)

A proposed mine exploration project in mountains outside Boise is advancing toward possible approval.

A 45-day objection period to the 2023 CuMo Exploration Project is open until Nov. 4. That’s after the Boise National Forest on Friday issued a decision notice and review document, finding that the CuMo project would have no significant environmental impact. 

Proposed by the Idaho Copper Corporation, the CuMo exploration project would be a four-year test drill, slated in an area 14 miles north of Idaho City, a small town about northeast of Boise. 

An analysis found the project area could have deposits of silver and critical minerals used in renewable energy, national defense and last-ditch efforts to expand drinking water availability. 

The decision notice isn’t approval of the project plan, Boise National Forest Forest Supervisor Brant Peterson wrote in the notice. Whether the project plan is approved relies on the company accepting measures to mitigate the project’s impacts “on surface resources and the posting of financial assurance to ensure reclamation for project-related disturbance,” he wrote. 

The U.S. Forest Service anticipates making a decision on the project by Jan. 1.

Environmental advocates are still worried the test project could taint headwaters that feed into the Boise River, and they have been skeptical that regulators have fully identified possible impacts, the Idaho Capital Sun reported.

But Peterson, in a decision notice posted Friday with other review documents, found that the project with mitigation measures “will not significantly affect the quality of the human environment,” adding that an environmental impact statement won’t be prepared.

Conservation organizations announced in a news release Monday that they plan to file an objection, saying that the U.S. Forest Service must “address public concerns about impacts to the Boise River watershed, fish, and wildlife before the project proceeds.”

More than 99% of public comments that the U.S. Forest Service received on the CuMo project were opposed to the project, Idaho Conservation League Public Lands and Wildlife Director John Robison said in the release. 

“We are disappointed that, in spite of all these concerns, the Forest Service’s draft decision doesn’t make any significant changes to this controversial project,” Robison said.

Idaho Copper Corporation CEO and COO Andrew Brodkey previously told the Sun that the test project wouldn’t harm the Boise River. And he stressed a possible, actual mine would be years away — depending on the economic prospects — and involve more environmental analysis beforehand. 

In an interview Monday, Brodkey said the Boise National Forest underwent “incredibly intense, comprehensive studies” to reach its conclusion.

“We consider this to be exactly what the agency needed to do, was designed to do and carried out to reach the conclusion that our exploration activities are not going to have an impact on the environment,” Brodkey told the Sun.

The Boise National Forest’s decision includes project design features the agency’s proposed mitigation measures to protect public health and safety, such as using non-toxic drilling fluids and biodegradable synthetic polymer and bentonite. That’s along with a spill avoidance and control plan, restricting access to the project area and safety measures in fuel transportation.

“All applicable state and federal laws, policies, and regulations will be followed. Adherence to these protection measures will ensure potential effects to public health and safety are minimized,” the Boise National Forest’s decision notice said.

In its review, Boise National Forest officials wrote that “the proposed operation will not threaten or endanger fish or wildlife resources.” 

If the company pumps water from Grimes Creek, Boise National Forest officials wrote in a project operations plan review that a screen to be placed near the water intake will prevent fish from entering the pump.

“The effects on the human environment for the (project with mitigation measures) are reasonably expected to be similar to other exploratory drilling projects,” the decision notice said, adding that previous U.S. Forest Service reviews found that the project with mitigation measures “will not involve any highly uncertain or unknown risks.” 

“I am confident that we understand the effects of these activities on the human environment,” Peterson wrote. “No unique or unusual characteristics about the area or the (project with mitigation measures) will lead to an unknown risk to the human environment.”

The four-year test drill project also involves two years of post-drill clean up work, formally called reclamation.

The planned project area is 2,917 acres. The company’s proposed test drill project would affect only 72 acres, Brodkey previously said.

The test would feature 122 drill pads and construction of 8.9 miles of temporary roads. Within two years after the project is completed, all drill pads and temporary roads created would be removed and restored.

Afterward, the company plans to close off and cap up to 250 drill holes, “so that there can’t be any contamination,” Brodkey previously told the Sun. 

The Idaho Copper Corporation is advancing the CuMo Project toward “feasibility and its goal is to establish itself as one of the world’s largest and lowest-cost primary producers of molybdenum,” the company said on its website. 

The annual operation season for the CuMo exploration project would be from April 15 to Dec. 15, as weather allows, according to the Boise National Forest’s decision notice. That would allow up to 32 months of drilling over four years. 

Sixteen months of post-drilling reclamation work could occur over another two years, according to the decision notice.