&EPA United States Environmental Protection Agency EPA Signs Record of Decision for the United Nuclear Corporation Superfund Site United Nuclear Corporation McKinley County, New Mexico March 29, 2013 This fact sheet will tell you about: • The Record of Decision (ROD) for the Sur- face Soil Operable Unit Site History • For More Information On the Web Mexico in May 1977. The mill operated from 1977 to 1982, and processed ore primarily from two of United Nu- clear Corporation's nearby mines: Northeast Church Rock and Old Church Rock. Uranium ore was processed at the facility using a combination of crushing, grinding, and ac- id-leach solvent extraction methods. The milling operation produced acidic slurry of ground rock and fluid (tailing) that was pumped into the tailings area which consists of three cells. An estimated 3.5 million tons of tailings were disposed in the tailings impoundments (EPA, 1988a). EPA selected the Preferred Alternative presented in the Proposed Plan because it is expected to be protective of human health and the environment, complying with regulations, and utilize perma- nent solutions and alternative treatment technol- ogies to the maximum extent practicable. Site History The UNC Site includes a historic uranium mill that was licensed to operate by the State of New Northeast Church Rock Mine (A) North Mill Cell Central Mill Cell LEGEND Mine Site I | Mill Site and Osposal Cells Step Out Area ~ Structures South Mill Cell Figure 1: Northeast Church Rock Mine and United Nuclear Corporation site map Introduction In July 2012, the U.S. Environmental Protection Agency (EPA) accepted public comment on the Surface Soil Oper- able Unit (OU02) Proposed Plan for the United Nuclear Corporation Superfund (UNC) Site. The comment period began on July 20, 2012, and ended on September 21, 2012. On March 29, 2013, EPA, in consultation with the New Mexico Environment Department (NMED), signed the Record of Decision for the remedy for the OU02. Details of the Selected Remedy Hie selected remedy (Alternative 2) includes the transpor- tation, receipt, consolidation, and disposal of NECR Site mine waste at the UNC Site within the Tailings Disposal Area (Figure 1). EPA identified Alternative 2 as EPA's preferred remedy in the Surface Soil Operable Unit Pro- posed Plan for the UNC Site. Principal threat waste is not a part of this selected remedy and principal threat waste from the Northeast Church Rock Site will not be disposed of at the UNC Site. The O&M cost is estimated at $100K year which was calculated as a percentage of the remedy. The net present worth of O&M for 30 years was $1,230,000 (rounded). This was part of the $41.5 million es- timated for the entire project. The design and li- cense approval could take between two and four years; construction is projected to take an addi- tional four years. EPA placed the UNC Site onto the National Priorities List (NPL) of Superfund sites m 1983 [48 Fed. Reg. 40658 (Sept. 8, 1983)] because contaminated liquids had seeped from the tailings at the UNC Site and contaminated the underlying ground water, and because there were toxic emissions to surface water and air (EPA, 1988b). Acidic liquids had seeped from the tailings located in the unlined disposal cells into the underlying alluvium deposits (re- ferred to as the Southwest Alluvium) and also into two deeper zones (Zones 1 and 3) of the Upper Gallup Sand- stone Formation, contaminating the ground water with heavy metals, radionuclides such as uranium and radium, and other chemical constituents. In 1988. EPA and the Nuclear Regulatory Commission (NRC) signed a Memorandum of Understanding (MOU) regarding the UNC Site [53 Fed. Reg. 37887 (September 28, 1988)]. The EPA and the NRC have overlapping au- thority in connection with the UNC Site, and the MOU ------- was developed to help assure that remedial actions occur in a timely and effective manner. EPA issued a Ground Water Operable Unit ROD in Sep- tember 1988 selecting a remedy for the contaminated ground water that included extraction of the ground water and treatment by evaporation. Under the oversight of EPA, United Nuclear Corporation constructed the remedy in 1989 and continues to address ground water contamination under the 1988 ROD. Ground water monitoring and ex- traction wells are located at the boundary and down- gradient of the Tailings Disposal Area. Ground water mon- itoring and remediation of the contaminant plumes are on- going. United Nuclear Corporation submitted a final reclamation plan to NRC which was approved in March 1991. Between 1988 and 1996, United Nuclear Corporation cleaned up the tailings disposal area including decommissioning of the mill facility, remediation of radium contaminated soil, capping of the tailings cells, installation of extraction wells, and construction of evaporation ponds and an evap- oration system. All of these activities were completed un- der NRC oversight, and maintenance of the soil cleanup action continues. For More Information Janet Brooks EPA Region 6, Remedial Project Manager Tel: 214.665.7598 or 1.800.533.3508 (toll free) brooks ,i anet@epa. gov Jason T. McKinney EPA Region 6, Community Involvement Coordinator Tel: 214.665.8132 or 1.800.533.3508 (toll free) Mckinnev.iason@epa.gov Earle Dixon Project Manager New Mexico Environment Department Tel: 505.827.2890 Earle. dixon@state ,nm .us For press inquiries, please call the EPA Press Office at 214.665.2200. Information Repositories are available at: Octavia Fellin Public Library 115 West Hill Avenue Gallup, NM 87310 Tel: 505.863.1291 Navajo Nation Superfund Office Highway 264/43 Crest Road St. Michaels, AZ 86511 Tel: 928.871.6859 On the Web On the internet, the Record of Decision can be found at: http://www.epa.gov/region6/6sf/6sf-decisiondocs.htm Information about U.S. EPA Region 6 and the Superfund Program can be found at: http: //www. epa. gov/region6/6sf/ 6sf.htm Call U.S. EPA at 1.800.533.3508 (toll free) to receive a Spanish translation of this fact sheet. Para recibir una traduction en espanol de esta Hoja de Da- tos, comunicase con la Agencia de Protection del Medio Ambiente de los EEUU (la EPA) al numero de telefono 1.800.533.3508 (llamadagratis). &EPA United States Environmental Protection Agency Region 6 1445 Ross Ave. (6SF-VO) Dallas, TX 75202 ------- |