CuMo Mine

GEAS is a member of the Idaho Families for Clean Water coalition, which opposes the proposed CuMo Mine Project in the headwaters of the Boise River.   

Exploration and mine development for the CuMo Project are extremely controversial. The exploration site is upstream of half of Idaho’s population, and the Boise River watershed provides more than 20 percent of Boise’s drinking water supply. According to the Environmental Protection Agency (EPA), mining is the number one toxic polluter in the U.S.

The US District Court has put the exploration project on hold twice because the Forest Service had failed to take an adequate look at the project’s impacts on groundwater and rare plants following the Pioneer Fire. A spate of recent mine accidents on the Animas River in Colorado and the Mount Polley Mine in British Columbia have raised concerns about mine development upstream of communities.

Background Information and History

Idaho Families for Clean Water and CuMo Project Update by Pam Conley (October 2015)

Golden Eagle Audubon Society (GEAS) has been working on the CuMo mining exploration project since 2005 as part of the Idaho Families for Clean Water (IFCW) coalition. This coalition is composed of GEAS, the Idaho Conservation League (ICL), the Sierra Club, Idaho Rivers United (IRU), Trout Unlimited (TU), Great Old Broads for Wilderness, and Advocates for the West. We got together in 2005 over concerns about the proposed cyanide heap leach gold mine in Atlanta, ID. We were successful in getting that project stopped. 

We work on issues that affect the Boise River watershed which, as you know, is fabulous for wildlife and recreating, as well as being an important water supply. We have been working diligently to make sure these projects abide by the various environmental laws that were put int place to protect the public health and environment. TU and Idaho Fish & Game have also worked on rehabilitation projects on lower Grimes Creek to heal past mining scars.

CuMo Mine Exploration Project History

CuMo is a word made from the periodic table symbols for copper-Cu, and molybdenum- Mo. Idaho CuMo Mining Corporation (CuMoCo), a Canadian mining company based in Vancouver B.C., says the CuMo project has the potential to be the largest open pit molybdenum mine in North America. It could be five times larger than the Thompson Creek moly mine near Challis, Idaho. 

2005 - 2010

The initial permit to explore the CuMo project site on upper Grimes Creek, above Idaho City and Centerville, Idaho, was received in September 2005 and work started in June of 2006. They were drilling holes to determine the extent of the mineral deposit and its purity. Their project was approved under a categorical exclusion by the U.S. Forest Service (FS) which meant the FS was saying there would be no impacts from the project so an environmental assessment wasn’t needed. In 2007 CuMoCo was looking to expand its exploration project and wanted to build twelve more miles of roads and drill lots more holes. They were trying to get the work included under their original permit. 

In September 2007 the Idaho Conservation League (ICL) requested that the FS do an Environmental Impact Statement (EIS) on the proposal for the twelve miles of new roads. In October of 2008 our coalition, Idaho Families for Clean Water (IFCW), took a tour of the CuMo site up on Grimes Creek. In November 2008, ICL sent another letter to the FS requesting they do an environmental assessment of the expanded project. In June of 2009, responding to pressure from our coalition the FS finally decided to rescope the project which means they asked for items that the public would like to see covered in an environmental analysis of the project. IFCW sent in comments in June 2009 with items we wanted to see analyzed and requesting an Environmental Impact Statement (EIS) be done on this project.

In July 2010 the FS released the CuMo exploration project draft Environmental Assessment (EA). We had been requesting public meetings to present the EA to the public and the FS finally agreed to three meetings, one in Garden Valley, one in Boise, and one in Idaho City. We had great turn outs at these meeting and folks learned a lot about the project. We had about 30 days to comment on the draft EA which we found lacking in various ways and felt the project needed an EIS.

In February 2011 the Forest Servive published its decision notice on the project with a Finding of No Significant Impact (FONSI). This meant that they felt the analysis was adequate and they were ready to allow CuMoCo to proceed with their plans.

In July 2011, after losing our appeal of the FS Finding of No Significant Impact (FONSI) to the Regional FS Supervisor, three of the IFCW coalition members, GEAS, ICL, and IRU filed a law suit against the FS in federal court. Advocates for the West represented us in this law suit. 

The case was decided on August 29, 2012 and US District Judge Edward J. Lodge found that the Forest Service had acted arbitrarily and capriciously by approving the CuMo Exploration Project without examining potential effects to groundwater. The Judge found that the FS needs to conduct baseline groundwater studies, conduct a monitoring program before, during and after drilling, and develop mitigation measures in case water resources are degraded:

"The very nature of drilling holes 1,500 to 3,000 feet into the ground seems likely to impact the

underlying surface including groundwater.  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…These are significant environmental concerns which

demand at least baseline analysis and/or at least some monitoring mechanism to give some

assurance to the [Forest Service's] assumptions..."

This was a great win for the public and all of us who care about the Boise River watershed. The FS released the Draft Supplement Environmental Assessment (Supp-EA) to address the groundwater issues on August 15, 2013. Public meetings were held in: Idaho City, Boise, and Crouch. The deadline for submitting comments on the Supp-EA was September 18, 2013.

April 2015 -- The FS released the Draft Supplemental Decision Notice and FONSI and updated Supplemental Environmental Assessment (Supp-EA) which includes the new baseline ground water information as well as other updated information. The Forest Service stood by their decision that there will be No Significant Impact and that an EIS is not needed. We had 60 days to comment on this document and filed our objections on July 11, 2015. The FS then had 45 days to respond to our objections. We had some meetings with FS and CuMo to discuss some of our objections and see if we’d be willing to drop some of them if CuMo agreed to some of our requests. Most of our objections still stand. The FS came out with their final decision on October 5, 2015 which was a Finding of No Significant Impact and that CuMo can proceed with exploration activities. 

We are currently pursuing a law suit to challenge this decision based on lack of a lack of groundwater baseline information, impacts to Sacagawea bitterroot and a number of other issues. The CuMo documents can be found at

1872 Mining Law

Until the 1872 Mining Law is changed the public will get a raw deal on these mining projects. The law mandates that mining is the best use of public lands and mining must be given preference over all other uses- from drinking water to hunting, fishing, and recreation. Mining companies pay no federal royalties for the minerals they extract and the bonds they pay for clean up are never enough to do the job right with many companies declaring bankruptcy before they clean up a site.

For more information visit:

Idaho Rivers United    Idaho Conservation League  

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"Golden Eagle Audubon Society" is a 501(c)3 non-profit organization. P.O. Box 8261, Boise, ID 83707

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