Summary:
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--Humic or carbonaceous material the main concentrator of U. Roll front--S species, "sour" gas, FeS2. Bedding sequences with low dips; felsic plutons or felsic tuffaceous sediments adjacent to or above host rock are favorable source for U. Regional redox interface marks locus of ore deposition.
Weathering Oxidation of primary uraninite or coffinite to a variety of minerals, notably yellow carnotite as bloom in V rich ores.
Geochemical and Geophysical Signature U, V, Mo, Se, locally Cu, Ag. Anomalous radioactivity from daughter products of U. Low magnetic susceptibility in and near tabular ores.
Mineralization is associated with lenticular, channel-type upper Salt Wash light brown to light gray medium to fine grained sandstones with thicknesses greater than 30 feet, with material present as flakes or trash pockets and/or accompanying green or gray mudstones above or below the sandstone beds (Carter and Gualtieri, 1965).
Other hypotheses for the source of the mineralization include uranium derived arkosic sediments in underlying terrigenous rocks, and from hydrothermal solutions associated with intrusive rocks. (Finch, 1967). Of the hypothesis, Shawe’s is, with various modifications, the most widely believed. Uranium once liberated from its’ source travelled as a mobile ion in originated meteoric waters in fluvial sandstones until localized by reducing environments created by carbon pockets, pyritic zones and possibly brines or gases associated with hydrocarbon maturation.
One feature noted at the SMC by UCC and Denison geologists (Hollingsworth, 1989, 2015 and Showalter, 2015), is the presence of a colloquially-termed “red front”. This is an important ore control that marks the change from red oxidized to gray unoxidized sandstone in the mineralized
horizons.
Summary:
Traditionally in southwest Colorado and southeast Utah, uranium and uranium-vanadium deposits were owned or controlled by mining companies of various sizes. Some mines were controlled by the companies that owned the mills, but many mines had owner/lessees that shipped their ore to the regional mills. To which mill to ship depended on the toll contracts and the mineralogy of the uranium and host rocks.
The mills were conventional surface facilities that processed the ore to obtain the uranium. Conventional milling is one of the two primary recovery methods that are currently used to extract uranium from mined ore. A conventional uranium mill is a chemical plant that extracts uranium using the following process:
1. Trucks deliver uranium ore to the mill, where it is crushed into smaller particles before being extracted (or leached). In most cases, sulfuric acid is the leaching agent, but alkaline solutions can also be used to leach the uranium from the ore. (In addi ........ 