Moab uranium mill tailings pile

The Moab uranium mill tailings pile is a uranium mill waste pond situated alongside the Colorado River, currently under the control of the U.S. Department of Energy. Locals refer to it as the Moab Tailings Pile. In 1952 U.S. geologist Charles Steen found the largest uranium deposit in the United States near Moab, Utah. The uranium was processed by the Uranium Reduction Company and the waste slurry was stored in an unlined pond adjacent to the river. The Uranium Reduction Company was sold in 1962 and renamed the Atlas Uranium Mill.

Aerial view of the Atlas Mill Site near Moab, Utah, prior to the removal of the tailings pile

After the mill was closed in 1984 the pond was capped. There was also a pile of mine tailings that was over 90 ft (27 m) tall at its highest point.[1] It is believed that pollutants from the waste tailings are leaching into the river, inferred from the lethal effect on fish, primarily from high concentrations of ammonia. The site was transferred to the United States Department of Energy for remediation under Title 1 of the Uranium Mill Tailings Radiation Control Act in 2001.[2] In August 2005 the Department of Energy announced that 11.9 million short tons (10.8 million tonnes) of radioactive tailings would be moved, mostly by rail, and buried in a lined hole. The proposed holding site is public land at Crescent Junction, Utah, about 30 mi (48 km) from the Colorado River. In February 2006 a final Environmental Impact Statement met with United States Environmental Protection Agency approval. The cost of the relocation was originally estimated to be $300 million, but 2008 Department of Energy estimates are in excess of $720 million.[3]

The contract for the first transfer of the tailings has been awarded and the first relocation is expected to occur in late 2008. A series of works to extract and evaporate the water and ammonia from the pile before it reaches the Colorado River has been completed.

DOE plan for re-location
The tailings pile in November, 2010, during the DOE's excavation and cleanup.

The current Department of Energy plan to move the tailings is contracted out to Portage-North Wind LLC who has begun hauling the tailings from the current Atlas Uranium Mill site to the tiny town of Crescent Junction, Utah by railroad. This plan is based on the most current funding schedule which will provide for a complete removal by 2028.

A series of amendments to the Defense Authorization Act, sponsored by Rep. Jim Matheson are attempting to move the completion date to 2019. If these become law, the rate of removal would be doubled.

According to the current plan, huge "dirty" trucks pull 40-ton containers filled with tailings to a structure that will be located between the talings and Potash Road. Once in the structure the containers would be covered by lids. A radiological survey verifies that they have no radioactive material on the outside, and the containers will then be hauled by "clean" trucks up to a railroad line to be placed on rail cars for the transportation to the disposal site near Crescent Junction. Dirty trucks will never travel to the clean side of the lidding structure, and clean trucks will never be on the dirty side.

Once at Crescent Junction the process will be reversed, with the exception that the tailings will be dumped out of end gates rather than from the top to minimize dust as well as prevent contamination to the outside containers. A knife-edge seal will be employed to ensure no materials dribble out of the end gates during the transfer.

Six clean trucks will make 22 to 23 loops per day, on a 21.2-minute cycle, between the lidding area and the rail line. About 136 containers will be transported daily with a four-day-per-week schedule.

An overpass is to be built across Potash Road so haul trucks will never encounter highway traffic.[4]

Rail shipments began in April 2009.[5] The clean trucks were replaced by the rail line, with the containers still needed to be lidded as before. On March 3, 2010, the Department of Energy announced it had shipped one million tons of tailings.[6]

As of September 2019, 10 million tons of tailing (62%) have been removed.[7] A well field is located between the tailing pile and the river, which extracts and purifies groundwater before it enters the Colorado river. As of February 2014 799,000 pounds (362,000 kg) of ammonia and 3,990 pounds (1,810 kg) of uranium have been extracted from the wells. During low water periods, fresh water is injected into the wells.[8] On July 29, 2014 the 7 millionth ton of tailing was placed in the disposal cell.[9]

Disposal site

The tailings and other contaminated material are being buried near Crescent Junction, Utah, northeast of the junction of Interstate 70 and U.S. Route 191, about 30 miles from the tailing pile.[10] Excavation occurs in phases, two of which are complete as of July 2014. Each phase is about 45 acres (18 ha) and is excavated to about 25 feet (7.6 m). The contaminated material is first covered by a minimum one-foot (0.30 m) layer of interim fill, then by a four-foot (1.2 m) radon barrier composed of weathered mancos shale, a six-inch (150 mm) layer of sandy gravel as an infiltration and biointrusion layer, and 3 feet (0.91 m) of a frost protection layer composed of both soil and weathered shale. The cell is then topped with 6 inches (150 mm) of rock. Cover material is sourced locally and from Fremont Junction, Utah.[9]

When finished, the cell will be about 5,200 feet (1,600 m) long and 2,400 feet (730 m) wide. It is estimated to be about 25 feet (7.6 m) above ground and will be fenced. Currently the DOE owns 500 acres (200 ha) of land and has another 936 acres (379 ha) in a 20-year withdrawal for the disposal cell, buffer space, support area, and access road.[10]

References
  1. http://www.gjem.energy.gov/moab/documents/Crescent_Junction/RAS_RAP_July2008/RAS_RAPJuly2008.pdf
  2. Fact Sheet on Uranium Mill Tailings, Nuclear Regulatory Commission, retrieved December 16, 2012
  3. Salt Lake Tribune Editorial August 8, 2008 http://www.sltrib.com/ci_10144500"
  4. Archivist (10 October 2007). "DOE reveals details of plan to relocate Atlas tailings pile".
  5. Gulch, Coyote (10 March 2009). "Moab tailings pile: Movement by rail to start April 20th".
  6. "Office of Environmental Management". Energy.gov.
  7. https://www.gjem.energy.gov/newsreleases/Moab_UMTRA_Project_Reaches_Cleanup_Milestone.pdf
  8. Shenton, Lee. "Moab UMTRA Project: February 2014" (PDF). Archived from the original (PDF) on 22 February 2014. Retrieved 15 February 2014.
  9. "Moab, Utah, UMTRA, Project -- Disposal Cell". Retrieved 5 August 2014.
  10. "Over view of Moab UMTRA Pr oject" (PDF). June 2013. Archived from the original (PDF) on 10 August 2014. Retrieved 5 August 2014.
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