Summary:
Uranium mineralization in the Browns Park Formation within the Project and surrounding area is described as Wyoming sandstone roll type mineralization (Austin and D’Andrea, 1978).
While local mineralization displays some of the characteristics of known uranium deposits in the Gas Hills and Southern Powder River Basin of Wyoming, the mineralization is not necessarily typical of Wyoming roll-front deposits. The uranium mineralization within the Project is sandstone hosted and was deposited along a geochemical solution front, as is typical of roll-front mineralization and similar to other Wyoming sandstone hosted uranium deposits. The features which distinguish mineralization within the Browns Park Formation harken to its eolian origin and include the absence of carbonaceous trash and lack of stratigraphic controls, i.e., the lack of distinct vertical variations in grain size and the lack of intervening finer grained units (Rackley, 1972).
The source of uranium is described as syngenetic, alteration of the tuffaceous volcanic materials within the Browns Park Formation and/or the immediately overlying North Park Formation liberated uranium which was transported by ground water and concentrated along oxidation/reduction interfaces within the formation (Dribus and Nanna, 1982).
The localization of uranium appears to relate to local variations in permeability and the presence of pyrite and/or hydrogen sulphide. Uranium mineralization, in general, appears to be of the rollfront type mineralization common to the uranium basins in Wyoming, cutting across sedimentary structures (Pincock, Allen, & Holt, 1986).
Uranium mineralization occurs within an eolian stratigraphic unit of the Miocene Browns Park Formation. The host unit consists of tuffaceous, feldspathic sandstone which exhibits small to large scale festoon and planar cross-bed sets ranging up to several feet in thickness. Generally, uranium mineralization is the roll-front type mineralization, common to the uranium basins in Wyoming. Localization of uranium appears to relate to permeability and the presence of pyrite or hydrogen sulphide (Pincock, Allen, & Holt, 1986). The depth of mineralization averages slightly over 100 feet, but ranges from near surface to a maximum of 292.5 feet depending on location within the basin and local topography. Two general areas of mineralization occur within the Project, separated by less than two miles, which are herein referred to as Juniper Ridge East and Juniper Ridge West.
The deposit is relatively flat lying with formation dip less than 5o . The dip of the formation is highest at the margins of the basin and flatter near the center of the basin. The average thickness of mineralization above a 0.02% eU3O8 cutoff grade is slightly in excess of 10 feet.
More than 80% on the known mineralization occurs within the Juniper Ridge East portion of the Project.