Riley Pass Uranium Mine Documents
Approximately 250 acres of disturbed highwall, pit floor, and spoils areas have been identified for reclamation and clean-up needs. Hazards within the Riley Pass area include high walls, pit floor, unstable overburden, elevated radioactive materials, and heavy metals.
Onsite mine wastes are fine-grained particles readily dispersed by wind and surface water erosion. Contaminants of concern include arsenic, molybdenum, thorium, and uranium.
Concentrations range from below established background to ten times higher for sediment samples in impacted drainages and several hundred times higher for mine waste samples.
In addition to materials on the website, newsletters are used to keep interested parties informed of reclamation work. Newsletters have been previously distributed to interested parties and can be viewed or downloaded by clicking the following links:
Riley Vicinity Map
Riley Bluff Identification Map
Numerous maps and figures are available in documents associated with the Riley Pass Site. The links above provide basic site maps for reference.
Background Documents, Specifications, Assessment Reports
Non-Tronox Removal Action Memorandum - Full Document (pg 1-48)
The purpose of the above Action Memorandum is to request and document approval of the selected non-time critical removal action, as authorized by section 104 (42 U.S.C. 9604) of CERCLA, to address Bluffs A, F, I, J and K within the Riley Pass Uranium Mines site, located on the Custer National Forest, in Harding County, South Dakota. This action memo addresses the non-Tronox portion of Riley Pass.
The purpose of the following Action Memorandum is to request and document approval of the seiected non-time critical removal action, as authorized by section 104 (42 U.S.C. 9604) of the Comprehensive, Environmental, Response, Compensation, and Liability Act (CERCLA). This action memo addresses the Tronox portion of Riley Pass, which includes Bluffs B, C, D, E, G, and H, as well as associated retention ponds. Due to document size, the Action Memorandum is split into three sections to allow for downloading from this website. Please click on the following links to download files for viewing:
Tronox Removal Action Memorandum - Part 1 (site conditions, background, public health)
Tronox Removal Action Memorandum - Part II (proposed action and state specifications)
Tronox Removal Action Memorandum - Part III (specifications continued, terms and definitions)
The Custer National Forest, Sioux Ranger District with the assistance of EPA and the State of South Dakota, has developed this final cleanup plan for the Riley Pass Abandoned Uranium Mine in the North Cave Hills. The Final EE/CA was released November, 2006. Due to document size, the EE/CA is split into several sections to allow for downloading from this website. Please click on the following links to download files for viewing:
Final Engineering Evaluation/Cost Analysis (EE/CA)
Engineering Evaluation/Cost Analysis (EE/CA)Appendices
Appendix A: Description of Federal and State ARAR's (requirements)
Appendix B: Analytical Data for Riley Pass Site (1990)
Appendix C: Part I, Analytical Data for Riley Pass Site (1999 - 2000)
Appendix C: Part II, Analytical Data for Riley Pass Site - Surface Water Samples
Appendix D: Portage Environmental - Final Risk Assessment Report
Appendix E: Analytical Response Action/Cost Tables
Appendix F: Threatened and Endangered Species Coorespondence
Appendix G: Comment Responses
EE/CA Figures and Maps, Additional Documents
Figures and Maps - Part I
Figures and Maps - Part II
South Dakota School of Mines Final Impact Investigation
This report addresses and evaluates the potential environmental impact of abandoned uranium mining and exploration sites in the North Cave Hills, Harding County, South Dakota. Specifically, this report addresses:
• Off-site migration of sediment spoils and associated metals and radionuclides from the
North Cave Hills region of USFS administered lands into potentially impacted drainages (sediments and surface waters);
• Sliding, slumping, and sheet erosion of mining spoils and associated metals and
radionuclides from USFS administered lands onto adjacent private lands;
• Off-site migration of airborne dust particulates and associated metals and radionuclides
by wind erosion of mining spoils from USFS administered lands onto adjacent and regional private lands;
• Potential contamination to the regional ground water supply by introduction of metals
and radionuclides into regional aquifers that provide drinking water to local residents and livestock.
Due to document size, the Impact Investigation Report is split into several sections to allow for downloading from this website. Please view or download documents by clicking the following links:
Final Report Impact Investigation Part I
Final Report Impact Investigtation Part II
Final Report Impact Investigation Part III - Figures
Final Report Impact Investigation Part IV - Figures