An inferred relationship between some uranium deposits and calcium carbonate cement in southern Black Hills, South Dakota

Evidence resulting from geologic mapping in the southern Black Hills indicates that the areas marginal to some of the larger carbonate-cemented sandstones constitute favorable geochemical environments for the localization of uranium deposits. To determine whether these favorable environments are predictable a limited experimental core-drilling program was carried out. An extensive deposit was discovered in an area marginal to a sandstone well-cemented with calcium carbonate. The deposit has not yet been developed, but from the available data it appears that there is a significant quantity of mineralized rock present containing as much as 3.0 percent eU3O8.