From abstract: Slope and Bowman Counties, N. Dak., include an area of about 2,450 square miles in the southeastern part of the Fort Union coal region of North Dakota, South Dakota, and Montana. In anticipation of a future increase in the demand for the low-rank coal of this region as a fuel for electric power plants and as a raw material for various chemical synthesizing processes, Slope and Bowman Counties were investigated for deposits of lignite that could be mined by large scale strip mining methods. All the lignite beds of economic importance in this area are in the Fort Union formation, particularly in the Tongue River member. The beds are nearly horizontal, dipping about 25 to 50 feet per mile north and northeast from the Cedar Creek anticline in the southwest corner of the area.

Purpose: The main objective of the Dakota core drilling program was to determine reserves of uraniferous lignite based on chemical uranium and spectrographic determinations from unweathered samples, particularly from those areas where surface sampling of the beds during the previous field season indicated that significant deposits of uranium-bearing lignite might be present. A secondary objective was to obtain fresh samples and to measure the radioactivity of the overlying Oligocene White River and Miocene Arikaree formations from which the uranium in lignite is believed to have been derived.

This baseline risk assessment of ground water contamination at the inactive uraniferous lignite ashing site near Bowman, North Dakota, evaluates the potential impacts to public health or the environment from contaminated ground water at this site. This contamination is a result of the uraniferous lignite ashing process, when coal containing uranium was burned to produce uranium. Potential risk is quantified only for constituents introduced by the processing activities and not for the constituents naturally occurring in background ground water in the site vicinity. Background ground water, separate from any site-related contamination, imposes a percentage of the overall risk from ground water ingestion in the Bowman site vicinity. The US Department of Energy (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project is developing plans to address soil and ground water contamination at the site. The UMTRA Surface Project involves the determination of the extent of soil contamination and design of an engineered disposal cell for long-term storage of contaminated materials. The UMTRA Ground Water Project evaluates ground water contamination. Based on results from future site monitoring activities as defined in the site observational work plan and results from this risk assessment, the DOE will propose an approach for managing contaminated ground …