SUPPLEMENTARY INFORMATION:

I. Background

The NRC is making available to the public the “Environmental Assessment, DISA Premobilization Notification for High-Pressure Slurry Ablation Operations at the Mary Ann Abandoned Uranium Mine Waste Pile Site, Montrose County, Colorado.”

II. Introduction

The NRC is considering the approval of DISA's PMN for HPSA operations at the Mary Ann site. DISA needs NRC approval to proceed with mobilizing HPSA equipment to operate at the Mary Ann site. The PMN provides information about the site and proposed HPSA operations required in condition 19 of DISA's license.

As required by section 51.21 of title 10 of the Code of Federal Regulations (10 CFR), “Criteria for and identification of licensing and regulatory actions requiring environmental assessments,” the NRC has prepared an EA documenting its evaluation. The NRC concluded that DISA's proposed operations at the Mary Ann site would have no significant impacts and are consistent with the assessments in the NRC's generic 2025 EA for license issuance (ADAMS Accession No. ML25265A212) and the 2026 generic supplemental EA for flocculant use (ADAMS Accession No. ML26196A294).

A summary of the EA follows. Based on the results of the EA, the NRC has determined not to prepare an environmental impact statement for the license amendment and is issuing a FONSI.

III. Summary of the Generic Environmental Assessment

Description of the Proposed Action

The proposed action is approval of DISA's plans to conduct HPSA operations at the Mary Ann site. The Mary Ann site is located in Montrose County, Colorado, at the base of the Monogram and Davis Mesas, southwest of Paradox Valley. The site is approximately 6,500 feet above sea level. The license area is 1.72 acres, and the disturbed area would be approximately 0.86 acres.

DISA identified radiological background levels for the Mary Ann site, as described further in the EA. DISA will compare the results of surveys after HPSA operations to these background measurements to determine compliance with NRC requirements.

At the Mary Ann site, DISA plans to process approximately 1,656 cubic meters of AUM waste, weighing 4,217 tons. Approximately 1,839 tons of fines concentrates (material containing the concentrated uranium and thorium) would result from HPSA processing.

DISA will use a rock crusher to pre-crush all or part of the rock pile before mobilizing the HPSA equipment. The crushed rock will likely be stockpiled, ( printed page 52734) and DISA will install air monitoring equipment and use water as a dust suppressant. Secondary containment will be constructed to ensure that any spilled water is contained within the restricted area.

DISA will also establish a radiologically restricted area, contamination survey areas, radiation safety controls, restricted area controls, equipment laydown areas, and air monitoring stations. The restricted area will include the HPSA treatment equipment, fines concentrates storage area, Mary Ann AUM waste pile, and the crushed rock stockpile.

The HPSA process would require the use of 5,000 gallons of water per day. In addition, DISA will use approximately 276 kg of an anionic, polyacrylamide flocculant for the estimated 1,839 tons of fines concentrates. Assuming approximately 10,000 gallons of water remain at the end of HPSA operations, an estimated 193 grams of flocculant would be present in this water that could be discharged via sprinkler to the Mary Ann site ground surface as irrigation water. Any discharged water must meet NRC, Bureau of Land Management (BLM), State of Colorado, and local requirements.

The fines concentrates will be stored temporarily within restricted area in containers that are suitable for storage and transportation. Approximately one truckload per day of fines concentrates containers will be transported offsite per day to a permitted facility, such as DISA's planned storage facility Naturita, Colorado. Currently, the State of Colorado is reviewing an application from DISA for a storage facility.

After the HPSA treatment is completed, equipment will be decontaminated, released for unrestricted use based on contamination surveys, and transported offsite.

DISA will leave the Mary Ann site with the deposited coarse material in a condition that meets NRC requirements in the license and in 10 CFR part 20 for unrestricted release (25 millirem above natural background). Disturbed areas will be seeded and irrigated with treated water from the HPSA unit assuming it meets treatment standards or water that is transported onsite.

Other Permits and Approvals

DISA has submitted a Plan of Operations to the BLM for review. DISA has also submitted a mine permit application to the Colorado Division of Reclamation, Mining, and Safety (CDRMS). This mine permit application includes a stormwater management plan that must be approved by CDRMS.

The Need for the Proposed Action

The purpose of the proposed action is to enable DISA to conduct licensed activities at the Mary Ann AUM waste pile. In accordance with DISA's license, the NRC needs to approve a PMN for operations at a site before DISA may mobilize to that site.

Environmental Impacts of the Proposed Action

The NRC staff reviewed DISA's Mary Ann PMN for consistency with the NRC's 2025 and 2026 generic EAs. In addition, the NRC staff assessed DISA's proposed use of a crushed rock stockpile and the disposition of coarse material onsite after HPSA operations conclude. Based on these reviews, the NRC staff determined that the potential environmental impacts of HPSA operations at the Mary Ann site would not be significant. The NRC staff determined that further consultation under Section 7 of the Endangered Species Act (ESA) is not needed because proposed operations at the Mary Ann site would have no effect on threatened or endangered species.

The NRC designated the BLM as the lead agency to fulfill the NRC's and the BLM's collective responsibilities under Section 106 of the National Historic Preservation Act. The BLM's Section 106 process is described in BLM's EA for its approval of the Plan of Operations for the Mary Ann Pile site (available on BLM's website at eplanning.blm.gov/​Documents/​?id=​D5ADB72E-2543-F111-88B4-001DD8084607&​spid=​19cf9b0a-3f43-f111-88b4-001dd8084607#).

Environmental Impacts of the Alternatives to the Proposed Action

As an alternative to the proposed license amendment, the NRC considered the no-action alternative. Under the no-action alternative, the NRC would not authorize DISA to proceed with HPSA operations at the Mary Ann site. The Mary Ann site would remain unaltered, and the potential impacts would be associated with leaving the waste pile in place as it exists today.

Agencies and Persons Consulted

The NRC provided a draft of this EA to the State of Colorado. No comments were received.

IV. Finding of No Significant Impact

Based on its review, in accordance with the requirements of 10 CFR part 51, the NRC has determined that granting approval for HPSA operations at the Mary Ann site would not significantly affect the quality of the human environment and that site conditions, proposed operations, and potential impacts at the site are consistent with the assumptions and potential impacts assessed in the 2025 and 2026 generic EAs, with the exception of the use of a crushed rock stockpile. In the EA, the NRC staff assessed the potential impacts of the crushed rock stockpile and the management of coarse material resulting from the HPSA process. The NRC staff determined the impacts would not be significant given DISA's compliance with NRC, Bureau of Land Management, and State of Colorado requirements. In accordance with 10 CFR 51.31, the NRC concludes that the proposed action does not warrant the preparation of an environmental impact statement, and, pursuant to 10 CFR 51.32, a FONSI is appropriate.

Authority:42 U.S.C. 2011 et seq.

91 FR 52733