Idaho Falls District - Challis Field Office
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Molybdenum Mining on Public Lands in Idaho

Molybdenum is a locatable mineral under United States mining laws. Molybdenum is used as an alloy to make high-strength and corrosion-resistant steel. The Thompson Creek molybdenum mine, owned and operated by Thompson Creek Mining Company (TCMC), is located 20 miles southwest of Challis, Idaho.  It is the fourth largest primary molybdenum mine in the world and is Custer County's largest employer, typically accounting for one out of every five jobs in the county, 45 percent of its wages and salaries, and $114 million of Idaho’s total personal income. The mine began commercial production in November 1983, and the current plan of operations allows molybdenum mining to continue through approximately March 2016. 

TCMC submitted a modified mining plan of operations (MMPO) to the BLM, U.S. Forest Service, and Idaho Department of Lands in December 2008 that would allow the mine to continue to produce molybdenum until approximately 2025.  Under both the current mining plan of operations and the MMPO, the mine would continue to process the same amount of ore each day – approximately 30,000 tons from the bottom of the open pit.  However, the mine would require additional area for waste rock and tailings storage.  TCMC also began discussing a related land exchange with the BLM in May 2006, and proposed the land exchange in February 2009.

Thompson Creek Mine Expansion EIS and Land Exchange

The BLM, the U.S. Forest Service, the U.S. Army Corps of Engineers, the U.S. Environmental Protection Agency, the Idaho Department of Environmental Quality, and Idaho Department of Lands have prepared an environmental impact statement (EIS) to analyze the potential environmental effects of authorizing a modified mining plan of operations and issuing a Section 404 Clean Water Act permit for the Thompson Creek mine, and authorizing a related proposal to exchange lands in Custer and Bannock Counties.

On March 27, 2015 the agencies released the final EIS with a 30-day availability period. The decisions for the mine plan, 404 permit, land use plan amendment, and land exchange will not be issued until after the availability period and the agencies have had time to fully consider all public comments received during the availability period.

A mine truck descends into the pit at the Thompson Creek Molybdenum Mine in Custer CountyMarch 27, 2015 
Final EIS | Notice of Availability | NEWS Release
Forest Service (FS) Draft Record of Decision
Legal Notice, Draft FS ROD April 06, 2015

March 21, 2014
Draft EIS | Notice of Availability | NEWS Release

August 3, 2010
Scoping | Notice of Intent | NEWS Release

The Thompson Creek Mining Company has proposed to exchange 80 acres of private land in Bannock Co. and 775 acres of private land in Custer County for surface and mineral estate on 5,144 acres of Federal land in Custer County, under provisions in Sec. 206 of FLPMA.

The proposed exchange would require amending the BLM Challis resource management plan (RMP), to identify the Federal lands involved as suitable for exchange.  The environmental effects of the plan amendment are analyzed in the EIS.

The NOEP contains legal descriptions of the lands involved in the proposed exchange, objectives for the exchange, and ways to express concerns or comment on the proposal.

April 2013 Land Exchange Documents
Notice of Exchange Proposal (NOEP)

Last updated: 05-26-2015