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Location: 90 km SW from Rapid City, South Dakota, United States
310 Second AvenueEdgemontSouth Dakota, United States57735
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The Project’s deposit type is sandstone hosted uranium roll-fronts. The deposit is characterized by numerous vertically stacked roll-fronts controlled by stratigraphic heterogeneity and variability in groundwater oxidation-reduction potential. Individual roll-fronts are a few tens of feet wide, 5 to 10 feet thick, and often thousands of feet long. Collectively, roll-fronts result in an overall rollfront deposit that is up to a few hundred feet wide, 50 to 75 feet thick and continuous for miles in length.The uranium host units in the Dewey-Burdock area are the marginal marine Lakota and Fall River sandstone units within the Inyan Kara Group of earliest Cretaceous Age. The Lakota Formation was deposited by a northward flowing stream system. Sediments consist of point bar and transverse bar deposition. The stream channel systems are typical of meandering fluvial deposition. Sand units fine upward and numerous cut-and-fill sandstones are indicative of channel migration depositing silt and clay upon older sand and additional channel sands overlay older silts and clays. Uranium mineralization occurs in several stratigraphically different sands within the Lakota.Similar channel deposition occurred during Fall River time, but the channel sands are noticeably thinner with marine sediments immediately superimposed on the fluvial sands. The major sand unit in the basal Fall River is mineralized. On the Dewey side of the property, this mineralization is below the water table; however, on the Burdock mineralization is at or above the water table and is not considered economically viable by ISR.The lithologic units of the Lakota and Fall River Formations dip about 3° to the southwest off the flank of the Black Hills Uplift. This structure controls present day groundwater hydrogeologic conditions.MineralizationHistorical Tennessee Valley Authority (TVA) reports indicate that uranium minerals are all of +4 valence state and deposited from epigenetic solutions. Sandstone permeability controlled the migration of these epigenetic solutions and deposit formation. The deposit is characterized by numerous roll fronts in the overall deposit. Deposits with multiple roll fronts form because of heterogeneity within the host sands and changes in groundwater oxidation/reduction potential. The deposits are continuous for thousands of feet and in some instances several miles. Individual roll fronts range in thickness from 5 to 12 feet thick and 10 to 50 feet wide. Where roll fronts overlap or nearly overlap vertically, total deposit thickness can be tens of feet thick and hundreds of feet wide. Grade along the length of the roll fronts is highly variable ranging from below detectable up to tenths of a % eU3O8.
