Tomorrow afternoon on June 6, the U.S. Department of Energy, Office of Legacy Management (DOE-LM) in Grand Junction, Colorado will be conducting a ribbon-cutting ceremony for opening an interpretative center. Processing uranium began in 1943 at this location during the World War II Manhattan Project due to the proximity of nearby uranium ore deposits, ample sources of water, and railroad access. Various chemical extraction methods were tested to develop the milling process. Initially uranium was produced for the atomic weapons program and in 1953 President Eisenhower delivered his Atoms for Peace speech at the United Nations to find peaceful uses of atomic science and technology. This site became the field office for the Atomic Energy Commission (AEC) to promote and develop uranium resources which was later split into DOE and the Nuclear Regulatory Commission (NRC).
Uranium (U3O8) “yellowcake” can be refined by taking ore from conventional mines to a mill or at an above ground processing plant located near an in-situ recovery (ISR) mine, as described in Part 2. According to the Los Alamos National Lab website, “Uranium and its compounds are highly toxic, both from a chemical and radiological standpoint. Finely divided uranium metal, being pyrophoric, presents a fire hazard. In nature, U(VI) forms highly soluble carbonate complexes at alkaline pH. This leads to an increase in mobility and availability of uranium to groundwater and soil from nuclear waste repositories which leads to health hazards.”
Mitigating nuclear hazards at uranium processing sites are very different depending largely upon the method used to create yellowcake. A conventional mill produces large quantities of waste tailings (fine sand containing radium and metals) as well as liquid waste retained in ponds. Liquid wastes leaked or flooded many sites spreading surface contamination. In addition, mill tailings were used for construction materials like cement for communities near mill sites which can pose a radon exposure problem without proper remediation. Over 4000 “vicinity” properties were cleaned up in Grand Junction by DOE and the state program is currently managed by the Colorado Department of Public Health and Environment. Uranium mill tailings could continue to pose challenges in the U.S. and other countries, such as in Canada at Port Hope, for a 1,000 years.
In general, most of the hazards at mill sites, in addition to tailings management, are near surface issues affecting shallow groundwater and soil. By contrast, ISR mines inject chemicals into deeper groundwater zones that must be restored. In the U.S., all uranium production is controlled by the U.S. Nuclear Regulatory Commission or their Agreement States. According to NRC, “There are 37 Agreement States that regulate approximately 17,000 radioactive material licenses, or approximately 86% of all licenses nationally.”
Currently, the only operating uranium mill in the U.S. is the White Mesa mill operated by Energy Fuels at Blanding, Utah and regulated by Utah DEQ. Information on mills and ISR mines is available from several organizations including the non-profit Wise-Uranium.org.
My first professional employment after graduate school in 1984 was with the NRC assigned to oversee clean up uranium mill sites under the 1978 Uranium Mill Tailings Radiation Control Act (UMTRCA). The law directed U.S. Department of Energy (DOE) to remediate older, shut down mill sites (Title I). For active mills, NRC and Agreement States regulated the industry under the Title II program.
In 1985, I inspected the first mill site to be approved by NRC for remediation in Canonsburg, PA as mill tailings were being placed onto a synthetic and clay liner. I toured most of the other 21 mill sites under the UMTRCA Title I and II programs at various stages of remediation or closure as well as reviewed and approved environmental assessments and remedial action plans. The primary objective was to control radiation hazards by capping tailings in place or moving tailings to a new disposal site. Initially, groundwater cleanup at mill sites did not become a priority until about a decade later. One technical issue that I identified at Canonsburg was the importance of understanding clay mineralogy in natural and remedial designs in addition to hydraulic permeability considerations for limiting pollution migration at disposal sites.
From 2012 to 2016, I managed a dozen UMTRCA sites for DOE-LM including conducting groundwater investigations at Riverton, Wyoming and other sites and managing the three Grand Junction sites: the office (former Manhattan and AEC-DOE site), processing site that became Las Colonias Park, and the active disposal site. I’m most proud of contributing to the City Park by providing permit reviews and a federal grant to support redevelopment of the former mill processing site!
In summary, with adequate regulatory oversight and inspections, processes to produce uranium can be done safely and protect the environment.