Slick Rock, Colorado (Umtra Site)

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The Slick Rock site is located in the Dolores River Valley, 4.8 kilometers (three miles) northwest of the old post office at Slick Rock. The site comprises two separate areas that are approximately 1.6 kilometers (one mile) apart: the 37-hectare (93-acre) Union Carbide site and the seven-hectare (17-acre) North Continent site.

Estimated Site Total

(Thousands of Current Year Dollars)
	FY 1996	1997	1998	1999	2000
Environmental Restoration	12,997	4,061	892	843	1,732	Grey shaded area reflects annual cost estimates for the first five years of the site BEMR Base Case (as of October 1995) and includes 3% annual inflation, see Readers' Guide.
1996 Appropriation	10,585			These levels reflect the current estimates for compliance with applicable statutes and agreements (as of March 1996), see Readers' Guide.
1997 Congressional Request		9,721
(Five-Year Averages, Thousands of Constant 1996 Dollars)
	FY 1996-2000	2005	2010	2015	2020	2025	2030	Life Cycle*
Environmental Restoration	4,018	1,044	694	817				32,863
* Total Life Cycle is the sum of the annual costs in constant FY 1996 dollars.

FACILITY MISSION

The mission of the Slick Rock 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. Union Carbide Corporation/UMETCO has owned and operated the Union Carbide Corporation site since 1956. An upgrader became operational in 1957 and was shut down in 1961. Ore was delivered to the upgrader from mines in the Slick Rock area, and the resultant upgraded material was trucked to Union Carbide's Rifle, Colorado mill for further processing. The Trans Colorado Gas Company constructed a plant on five acres of land next to the site. The Old North Continent site was originally owned by Shattuck Chemical Company beginning in 1931. North Continent Mines, Inc. acquired the interests of Shattuck in 1934. Union Mines Development Corporation, a United States Government-established corporation, acquired the site in 1945 for the specific purpose of supplying uranium and vanadium for the Manhattan Project in World War II. The Federal Government took control of the site in 1949. Union Carbide Corporation acquired the property in 1957 and continues to be the owner.

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 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.

FUTURE USE

The Department of Energy acquired the Slick Rock disposal site (Burro Canyon) from the Bureau of Land Management via a legislative withdrawal and jurisdictional transfer. The disposal site will remain under the control of the Department and will be monitored and maintained in accordance with the Nuclear Regulatory Commission- approved Long-term Surveillance Plan. Under the provisions of the Uranium Mill Tailings Remediation Control Act, public access to the disposal site will be restricted. Surface remedial action at the former processing sites is being performed under a Remedial Action Agreement between the Department of Energy, the State of Colorado, and the private land owner. Under the terms of the Remedial Action Agreement, beneficial use of the site will be returned to the owners upon Nuclear Regulatory Commission certification of compliance with Subpart B of the Environmental Protection Agency ground-water protection standards.

ENVIRONMENTAL RESTORATION

Removal of the tailings, the source of ground-water contamination, from the former processing sites and transport to the Burro Canyon disposal site began in the spring of FY 1995. However, residual milling-related contaminated ground water remains.

Surface Project

Remedial action at Slick Rock began in April 1995. This report assumes that approximately 480,624 cubic meters (632,400 cubic yards) of materials will be transported by truck to the Burro Canyon disposal cell and that remedial action should be completed by December 1996. Four vicinity properties will be remediated concurrently with site remediation activities. Nuclear Regulatory Commission certification and licensing and transfer to the Long-Term Surveillance and Maintenance program will occur in FY 1998.

Major Surface Project Milestones

TASK	COMPLETION DATE Fiscal Year
Publish Remedial Action Plan	1996
Initiate and Complete Vicinity Property Remedial Action	1996
Site Remedial Action	1997
Nuclear Regulatory Commission Issues General License	1998
Transfer Disposal to Grand Junction Projects Office for Long-Term Surveillance and Maintenance Program	1998

The Slick Rock Remedial Action Plan outlines the contaminant distribution and remediation needed. The Nuclear Regulatory Commission and the State of Colorado have informally concurred on the Remedial Action Plan. Formal concurrence is expected in the fall of 1995, with publication of the final document in April 1996. 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 1998.

Ground-Water Compliance Project

The Department is developing a Programmatic Environmental Impact Statement pertaining to all 24 UMTRA sites. For a discussion of the Programmatic Environmental Impact 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 Slick Rock site once the Programmatic Environmental Impact Statement is completed.

This report assumes a natural flushing ground-water compliance strategy at the Slick Rock site. Removal of the tailings will remove the source of contamination for the alluvium ground water, and uranium concentrations should return to background levels after a period of natural flushing. For all types of ground-water compliance strategies, once the Nuclear Regulatory Commission determines the site to be in compliance with Subpart B of the Environmental Protection Agency Standards and it is certified, no additional long-term surveillance or monitoring will be conducted.

The total volume of contaminated ground water is estimated to be 106 million liters (28 million gallons) at the Union Carbide site and 45 million liters (12 million gallons) at the North Continent site. The contaminant plumes do not extend offsite. The ground-water contaminants of potential concern at the sites are cadmium, lead-210, iron, manganese, sulfate, uranium, sodium, radium-226, molybdenum, nitrate, selenium, strontium, thorium-230, vanadium, and polonium-210.

The following milestone dates have been established for planning purposes.

Major Ground-Water Compliance Project Milestones

TASK	COMPLETION DATE Fiscal Year
Baseline Risk Assessment	1996
Site Observational Work Plan	2004
Publish Environmental Assessment/Finding of No Significant Impact	2005
Publish Remedial Action Plan	2007
Compliance Strategy	2012
Licensing	2013

Monitoring wells at the processing sites provide representative ground-water samples from onsite and downgradient areas in the alluvium, Entrada, and Navajo Formations. A total of 47 ground-water locations were scheduled to be sampled during the 1994 sampling events. Ground-water sampling locations included eight monitoring wells at the North Continent site and 19 wells in the vicinity of the Union Carbide site.

All ground-water samples that exceeded the Environmental Protection Agency maximum concentration limits were from wells installed on or adjacent to the tailings piles. Uranium concentrations in ground water of the alluvium decrease rapidly immediately downgradient of the tailings piles, indicating that the tailings piles have impacted ground-water quality at the site.

With the natural flushing approach, contamination concentrations can be reduced naturally to maximum, background, or alternate concentration limits within 100 years, as established in the Environmental Protection Agency standards. During the first ten years of remediation verification monitoring will be performed to ensure that natural flushing is working as predicted. The data collected during this phase will be provided to the Nuclear Regulatory Commission in a confirmation report. Upon acceptance of the confirmation report, the site would be turned over to the Grand Junction Projects Office's Long-Term Surveillance and Maintenance program. This program will conduct "compliance monitoring" for up to 90 years. When maximum concentration limits or background or alternate concentration limits have been achieved, a certification report will be prepared to close out all Department of Energy involvement at this site.

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 Slick Rock site.