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Project Name: Sherwood Uranium Mine

Project Start Date:

Project End Date: Reclamation work completed in June 2000

Location: Near Wellpinit, WA, approximately 45 miles northwest of Spokane, WA. The mine is entirely within the interior of the Spokane Indian Reservation.

Nearest Town: Wellpinit, WA

Latitude: 47° 52' 44 " Longitude: 118° 07' 17"

Post-reclamation view of mine area.


Mine Location

 

Mine Location
Mine Location

Tribal, Agency and Public Involvement:

Spokane Tribe of Indians, U.S. Bureau of Indian Affairs, U.S. Bureau of Land Management, U.S. Environmental Protection Agency, Nuclear Regulatory Commission, U.S. Department of Energy, Washington State Department of Health, Western Nuclear (mine operator and land lessee), and public/private interest groups.

Environmental Review, Mine and Reclamation Plans, and Financial Assurances for Reclamation:

  • The National Environmental Policy Act (NEPA) process involved completion of an Environmental Impact Statement (EIS) for the project before the commencement of operations.
  • The Mine and Reclamation Plan, with subsequent modifications, was approved by BLM with significant input from the Indian Tribe and BIA.
  • BIA fully released Western Nuclear from their mine reclamation bond during October 2000.

The Western Nuclear, Inc (WNI) Sherwood Uranium Mill Project site was the first large conventional uranium mill and tailings site decommissioned and reclaimed under Washington State Department of Health (WDOH) Agreement State authority, derived from Title II of the Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA). UMTRCA requires that prior to termination of the license, the regulatory agency shall make a determination that the licensee has complied with all applicable standards and requirements. Under the Agreement States program, the state of Washington is repsonsible for approval of the remediation plans for WNI and for the site inspections to ensure that the actual remedial actions have been completed pursuant to the approved plans (NRC 1999).

Estimated Cost: Not available.

Reasons for Action:

  • The mine and business leases border a popular recreational lake (Coulee Dam National Recreation Area ). This NRA accounts for more than two million recreational user days per year.
  • The NRA has significant recreational values and uses by the public for camping, house boat rentals, fishing, boating and hunting.
  • Leases border a federally funded Tribal Wildlife Refuge and a trout spawning creek.
  • The mine site is critical winter habitat for deer and elk.
  • The site is visible from a popular State Campground and swimming beach located one mile from the mine.

History of Mine:

WNI completed construction of the mill in 1978, and it was operated until 1984. Nominal millings capacity was 2,100 tons of ore per day, with an average design ore grade of 0.088 percent U3O8. The company received ore and processed it from an open pit mine located approximately one-half mile west of the Sherwood mill. The mill ceased operationis prior to reaching the major portion of the ore-body, and the design ore grade was never realized. Acid-leached tailings were neutralized with lime prior to placement in the synthetically-lined Sherwood disposal cell. Approximately 2.9 million tons of tailings were placed in the impoundment from milling operations. The estimated radium-226 activity in the impoundment is 470 curies (WDOH 1998).

Mill decommissioning activities began in 1992 and were completed in 1995. Approximately 350,000 cubic yards of contaminated mill site soils, building equipment, and debris were excavated from the Sherwood processing site and hauled approximately one-half mile for placement in the synthetically-lined area of the tailings impoundment (WDOH 1998).

  • The Sherwood Open Pit Uranium Mine is located on the Spokane Indian Reservation.
  • The mine operated from 1976 to 1985.
  • Mining disturbance involved approximately 500 acres while the processing and tailing area disturbed an additional 200 acres.
  • At end of mining, and prior to reclamation, the pit seasonally contained surface water.

Pre-Restoration Aerial Photo Timeline:

Late 1960's
Late 1960's
More Photos >>

Mine Closure and Reclamation Objectives:

  • Maximize the potential for future retrieval of remaining ore in the deposit.
  • Return the mine to a condition that will not pose a hazard to public health and safety.
  • Return the site to a condition that will support wildlife habitat.
  • Create a self-sustaining vegetation community.
  • Enhance the visual appearance of the area that pre-dates WNI.
  • Use reclamation methods that are technically effective, cost efficient and employ tested engineering practices.

Design Narrative:

Specific Closure and Reclamation Activities

  • Remove all facilities.
  • Re-grade the overburden materials and mine the benches to create surfaces that promote drainage and minimize potential for ponding of water and erosion.
  • Establish stable slopes.
  • Replace the topsoil and growth media and revegetate with native plant species.
  • Monitor the performance during and after reclamation to ensure objectives are achieved.

Hydrologic/Hydraulic Analyses of the Reclamation Plan

  • Purpose: Evaluate erosional stability of the reclaimed mine site during a 100 year storm event (2.5 inches over a 24 hour period).
  • Methods:
    • US Army Corps of Engineers HEC-1 (COE, 1990).
    • Erosional stability of each bench evaluated by using permissable velocity method (Chow, 1959).
  • Conclusion: All of the benches will be erosionally stable and designed with enough capacity to transmit flow without overtopping any bench.

Slope Stability Analysis of the North No.3 Mine Waste Dump

  • Purpose: Evaluate stability of a proposed valley fill.
  • Suitable Factors of Safety: Static (1.5), Pseudo Static (1.0) post construction.
  • Method of Analysis: Bishop Method (PCSTBL4)
    • Material Properties - previous USGS investigations.
    • Phreatic surface assumed to be 5 feet above bedrock.
    • Seismicity - 0.10 g horizontal maximum acceleration, pseudo static coefficient of 0.05.
  • Results: Minimum Factor of Safety of 2.04 for static loading and 1.77 for pseudo static conditions.
  • Conclusion: Regraded overburden pile will be stable.
Slope Stability Analyses

 

Slope Stability Analyses
Slope Stability Analyses

Construction Photos:

Slope Reconstruction

 

Slope Reconstruction
Slope Reconstruction
  More Photos >>  

Slope Analysis Map:

Slope Vector Map

 

Aerial Photo Timeline During Reclamation:

May 1991

 

May 1993

Aerial Photo Timeline Post-Reclamation:

May 1995

 

June 2000

Materials Used:

Materials Used for Mine Reclamation

 

Native Grass Seed Mixtures Used
Area Before Revegetation in
November 1990

 

Area After Revegetation in
June 1991

Before and After Reclamation Aerial Photos:

August 1985

 

June 2000


Post-Reclamation Photos:

Post-Reclamation

 

Post-Reclamation
More Photos >>

 

Was this project successful? Yes

In November 2001, Western Nuclear, Inc. (subsidiary of Phelps Dodge) and the Sherwood Uranium Mine received the Department of Interior (DOI) National Award for Mine Reclamation Excellence by DOI Secretary Norton. This award is given out by the Secretary of Interior once a year. In recognition of this award, Western Nuclear was given a plaque during the BLM National Solid Minerals Conference held in during November 2001 in Las Vegas, Nevada.

For more information on this project, contact:

Kelly Courtright
District Mining Engineer, BLM
Spokane, WA
(509) 536-1218

Brad DeWaard
Resident Agent and Environmental Engineer
Western Nuclear, Inc.

Available Documentation: NA

Submitted by: Joseph K. Buesing

Photos By:

Date: July 2004

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