Riley Pass Uranium Mine Clean-up

2014 Spring Riley Pass Newsletter

The Forest Service, with the assistance of EPA and the State of South Dakota, has developed and is implementing a cleanup plan for the Riley Pass Abandoned Uranium Mine in the North Cave Hills.  This website provides background information and documentation associated with the site and updates regarding ongoing reclamation efforts.

The Riley Pass Uranium mines are located on 250 acres of the North Cave Hills region approximately 25 miles north of Buffalo, SD on the Custer National Forest.

Reclaimation work truck and scrapper at dipository site, bluff B

Recent Tronox Bankruptcy Settlement information

The United States has pursued a pending fraudulent conveyance lawsuit against Tronox‘s former parent, Kerr-McGee Corporation, and Anadarko Petroleum Corporation, which purchased Kerr-McGee. The fraudulent conveyance lawsuit alleges that Kerr-McGee and Anadarko defrauded Tronox and its creditors, including the United States, by imposing on Tronox all of Kerr-McGee’s environmental liabilities without sufficient assets to satisfy those liabilities. A number of Federal agencies (including the Environmental Protection Agency, the Department of Interior, and the Forest Service) filed claims. Eleven states, the Navajo Tribe, and all of Tronox’s other major creditors also filed claims. Most creditors claimed Kerr McGee had committed a multi-billion dollar corporate fraud.

Over the summer of 2012, the Southern District Court of New York tried the fraudulent conveyance case. On December 12, 2013, the court issued a decision that resolved most of the disputed issues in favor of the creditors. In essence, the court found pervasive evidence of both the intent to defraud creditors and a sophisticated plan to carry out that intent.  The Department of Justice provided information in April 2014 regarding a settlement agreement from this litigation.  Information regarding the settlement is available at: or at:

History and Background

Riley Pass uranium mining started in 1954 as authorized by the General Mining Law and Public Law 357.  Strip mining to reach uranium contained in the underlying Tertiary Fort Union formation coal seams removed up to 80 feet of overburden, which was piled on the outer edges of the rimrock.  No reclamation was required as directed by Public Law 357.

The site consists of twelve mined bluffs labeled “A” through “L” (refer to maps for specific sites).

In 1996, the Custer National Forest began working at the Riley Pass site under their Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) authority.  The Forest Service and Office of General Council determined that Tronox, LLC (formally known as Kerr McGee or Kermac) was the potentially responsible party (PRP) for site reclamation of six of the twelve Bluff mine sites.  Tronox signed an Administrative Order on Consent (Settlement Agreement) for Bluffs B, C, D, E, G, and H. The remaining Non–Tronox bluffs have no viable PRP.

The Forest Service is undergoing long-term efforts, reclaiming the site of both Tronox and Non-Tronox bluffs.  Millennium Science and Engineering (MSE) of Salt Lake City, Utah under contract with the Forest Service developed the reclamation plan for Non-Tronox Bluffs.

Contractor specifications are advertised each spring through Fed Biz Ops.  Background material and progress for contractors and the general public is readily made available at this site. 

If you are unable to locate items or have additional questions please contact: 

Dan Seifert, On-Scene Coordinator/Custer National Forest Assistant Forest Geologist at or at 406-446-4520. 

Riley Pass Uranium Mine Reclaimation Documents, Figures and Maps


Additional Resources and Links

Study Data:  Abandoned Uranium Mine Impacts on private and NFS land in western South Dakota -