Geologically, the main hosts for uranium-vanadium mineralization in the Sunday Mine Complex are fluvial sandstone beds assigned to the upper part of the Salt Wash Member of the Jurassic Morrison Formation, with minor production coming from conglomeratic sandstones assigned to the lower portion of the Brushy Basin Member of the Morrison Formation. Mineralization from both members is present at the property, with the mine production coming from the Salt Wash Member. Beds generally strike NW-SE and dip SW, with some exceptions within fault bounded blocks adjacent to Big Gypsum Valley.
According to the USGS Bulletin 1693 (Cox, D.P., and Singer, D. A., eds., 1986), the Deposit Model for the project is Model 30c, Sandstone Uranium – Tabular subtype.
Mineralogy: Uraninite, coffinite, pyrite in organic-rich horizons. Chlorite common.
Texture/Structure Stratabound deposits. Tabular U--intimately admixed with pore-filling humin in tabular lenses suspended within reduced sandstone. Replacement of wood and other carbonaceous material. Roll front U--in crescentic lens that cuts across bedding, at interface between oxidized and reduced ground.
Alteration Tabular--Humic acid mineralizing fluids leach iron from detrital magnetite- ilmenite leaving relict TiO2 minerals in diagenetic ores. Roll front- Oxidized iron minerals in rock updip, reduced iron minerals in rock downdip from redox interface.
Ore Controls Permeability. Tabular--Hu ........
