Shiprock Site, New Mexico (UMTRA Site)

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The former Shiprock site is located on a 93-hectare (230-acre) tract on Navajo Nation land, south of the San Juan River and adjacent to the town of Shiprock. Two piles of tailings covered approximately 29 hectares (72 acres). The former raffinate pond area and a few buildings were located to the west of the piles.

FACILITY MISSION

The mission of the Shiprock mill site was to provide uranium for the United States Government. The source of contamination was the residual tailings that remained after the milling process extracted the uranium. Various companies operated the uranium mill at the Shiprock site from 1954 until 1968. Before and during the milling operations, the site was leased from the Navajo Nation. When the Foote Mineral Company's lease expired in 1973, full control of the site reverted to the Navajo Nation.

The Environmental Management program is responsible for cleaning up surface- and ground-water contamination at the UMTRA sites. The Uranium Mill Tailings Radiation Control Act designated the residual radioactive material found at this site for cleanup and stabilization. The Act directed the Environmental Protection Agency to promulgate standards (Code of Federal Regulations Title 40, Part 192) and directed the Department of Energy to perform the cleanup. It also assigned the Nuclear Regulatory Commission to oversee and certify the cleanup, and license the completed disposal cell. The affected Tribes will participate in decisionmaking.

FUTURE USE

The Shiprock former processing site is located on Navajo Nation land. However, the long-term surveillance of the disposal cell will remain the responsibility of the Department of Energy through a Custodial Access Agreement between the Navajo Nation and the Federal Government. Provisions of the Custodial Access Agreement will allow the Department to have permanent access to the site and will likely include restrictions, as necessary, to protect the public health and safety. The provisions will include control of public access and posting of appropriate warning signs.

ENVIRONMENTAL RESTORATION

Surface remediation has been completed and the source of contamination has been stabilized. However, residual milling related contaminated ground water remains.

Surface Project

Remedial action was completed in November 1986 at the Shiprock former processing site. It involved consolidating approximately 2.1 million cubic meters (2.8 million cubic yards) of residual radioactive material and placing it in a controlled, engineered disposal cell to preclude further release of contaminants into the environment, including the ground water. Fifteen vicinity properties were remediated concurrently with site remediation activities. The Nuclear Regulatory Commission certified the site in May 1991, and this report assumes that the Commission will license the disposal cell in October 1996.

The Shiprock Remedial Action Plan outlined the contaminant distribution and necessary remediation. The Remedial Action Plan, which requires Nuclear Regulatory Commission concurrence, was published in June 1985. The UMTRA Surface Project will conduct surveillance and maintenance of the disposal cell after completion of remedial action and prior to its transfer to the Grand Junction Projects Office's Long-Term Surveillance and Maintenance program in FY 1997.

Ground-Water Compliance Project

The Department is developing a Programmatic Environmental Impact Statement pertaining to all 24 UMTRA sites. For a discussion of the statement, see the UMTRA program narrative in the New Mexico section of this report. Site-specific National Environmental Policy Act documentation will be developed to propose an appropriate ground-water compliance strategy and reasonable alternatives for the Shiprock site once the Programmatic Environmental Impact Statement is completed.

This cost estimate assumes that the ground-water compliance strategy will be natural flushing with a passive flow-through barrier. Because of the existence of ambient contamination in the background ground water, additional site-specific information will be collected to fill data gaps and to determine the applicability of the supplemental standards strategy. For all types of ground-water compliance strategies, once the Nuclear Regulatory Commission determines that the site is in compliance with Subpart B of the Environmental Protection Agency Standards and the site is certified, no additional long-term surveillance or monitoring will be conducted.

The total volume of contaminated ground water is estimated to be 984 million liters (260 million gallons), and the contaminant plume extends offsite. The ground-water contaminants of potential concern are antimony, arsenic, cadmium, magnesium, manganese, nitrate, selenium, sodium, strontium, sulfate, and uranium.

During the ground-water project, the Department must explore two hydrologic regimes in detail: flood plain and terrace. The flood plain regime has known contaminant levels. Additional information is necessary to predict ground-water movement more accurately. The origin of the water in the terrace system has not yet been established. Drilling further from the former milling site will determine whether the area is recharged or the water in the terrace is predominantly from the milling operation.

At present, there are eight monitor wells on the terrace, 34 monitor wells on the north and south flood plains, and 20 surface-water locations that are currently monitored or have been sampled in the past. Monitoring wells located in the terrace alluvium have not provided adequate information to define the real extent of the contamination to the east, south, or west of the former mill site. All samples collected from terrace monitoring wells during 1994 show evidence of contamination by former milling activities. Ground-water samples collected from background monitoring wells indicate that sulfate concentrations in background ground water are relatively high, but uranium concentrations are low.

Direct Program Management/Support

Program management supports management efforts for the National Environmental Policy Act process, site characterization and licensing, public information/participation, applicable state and federal regulator costs, quality assurance audits, program and management support for the technical assistance contractor, special studies, document control, technical assistance contractor site and technical management, cost and schedule controls, planning and preparation of the federal budget, and the Environmental Management Progress Tracking System.

FUNDING ESTIMATE

The following table presents estimated funding information for the Shiprock site.