ABSTRACT

Uranium mineralization was discovered in surface exposures of the rocks in the southwestern Williston Basin in 1948 by geologists of the U.S. Geological Survey. Continued exploration during the 1950's by the Survey and by private companies and individuals led to the discovery and delineation of commercial concentrations of uranium assocated with lignite beds. Mining began in extreme southwestern North Dakota and northwestern South Dakota in 1963. All mining ceased by the late 1960's following the end of the stretched-out uranium buying program of the United States Atomic Energy Commission. Presently, active leasing and exploration programs are being carried out in much of the western part of the Williston Basin. The potential for substantial discoveries of epigenetic uranium deposits in the sandstones of the Paleocene and Cretaceous ages appears excellent.