Abstract

A major exploration drilling program was undertaken during 1969 on approximately 25,000 acres of uranium leases and claims in the Lost Soldier-Green Mountain area by The Colorado Corporation. This drilling resulted in the discovery of a new sandstone uranium deposit in the Battle Spring formation. Work to date has partially delineated reserves mineable by open-pit methods, with additional potential for open-pit and underground reserves.

The deposit occurs in the lower part of the Battle Spring formation of Tertiary age. The lithology of the Battle Spring in the mineralized area consists of conglomerate, sandstone, and shale characteristic of through-flowing paleo-stream sedimentation. Structurally, the beds containing the ore occurrences lie on the west limb of the Lost Soldier anticline and dip westward; the Battle Spring is further deformed by a major east-west fault zone which passes through the central part of the property. The topography of the property is characterized by moderate recent dissection of Late Tertiary or Pleistocene age (?) pediment surfaces.

It is felt that the ore deposits are initially related to the primary sedimentation of the paleo-stream environment; subsequent oxidation and supergene enrichment during Late Tertiary erosion cycles probably emplaced the uranium in its present location. Oxidation related to recent erosion is further modifying the occurrences. Control of ore distribution in its present location by stratigraphic and structural features is indicated.