Sandstone-hosted roll-front uranium deposits with potential for in-situ recovery
(enCore’s 35-75 Property is located adjacent to, and along the southern boundary of the Company’s Coal Hill Property described in the next section of this presentation. Therefore several of the attributes of the Coal Hill Property are similar to those of the 35-75 Property as described in this section.)
The 35-75 Property contains two private mineral leases and 26 unpatented mineral claims covering approximately 1,170 acres.
The property hosts uranium-bearing sandstones of the Eocene Wasatch Formation and is adjacent to and on trend with Cameco’s Smith Ranch ISR uranium mine.
enCore Energy Corp. entered a purchase and sale agreement with Energy Fuels Inc. to acquire the 35-75 property.
There are no current uranium resources or reserves on the 35-75 property.
Geology and Mineralization
The 35-75 Property (as well as the Coal Hill Property) is located within the southern Powder River Basin, on the western side of the basin axis. The Powder River Basin is the most prolific ISR producing uranium district in the U.S. The basin is a north-northwest trending, asymmetrical syncline that extends from central Wyoming into southern Montana and from the western slopes of the Black Hills to the eastern flank of the Big Horn Mountains. The area is characterized by shallow, northeast dipping strata forming low bluffs and broad flat uplands cut by gullies from recent erosion. Cretaceous and early Tertiary sedimentary and volcaniclastic rocks cover most of the surface within the basin.
Locally the surface units are members of the Paleocene Fort Union Formation and the overlying Eocene Wasatch Formation. The Fort Union Formation is a fluvial sedimentary unit consisting of fine- to coarse-grained arkosic sandstone interbedded with siltstone, mudstone, and carbonaceous material. The Wasatch formation is the youngest strata on the 35-75 Property and contains sandstones, clays and shales. On other properties in the Powder River Basin, uranium has been mined from several sandstone horizons within each of these formations.
During a period of deformation and uplift of the Powder River Basin, layers of clastic rock were deposited into the Wasatch formation along with bentonitic clay layers. The clay layers were the result of intermittent silicic volcanism and were important to the formation of the uranium mineralization.
The uranium deposits of the Powder River Basin are classified as roll-front style mineralization produced by the dissolution, transport and deposition of uranium at irregular, active boundaries where a reducing environment balances the oxidative capacity of the uranium-bearing ground water.
The deposits of the Powder River Basin are typically multiple “C-shaped” roll fronts distorted by variations in the gross lithology of the host sandstone unit. Individual rolls range in thickness from 3 to 20 feet and may be 3,000 feet in length. The individual ore-grade beds are dispersed throughout the mineralized zone, but the mineralized sections of sandstone may approach 500 feet in thickness, as they occur in stacked deposits.
Based on the results of exploration drilling conducted in the 1960s and 1970s, together with anomalous areas identified by an alpha track radon survey conducted by Magnum Uranium Corp., Magnum estimated the property may host a mineral resource occurring as stacked roll front type. The target of further exploration has a potential of about one million or more, pounds U3O8, at an average grade in the range of 0.1% to 0.12% U3O8. The potential quantity and grade is conceptual in nature, as there has been insufficient exploration to define a mineral resource and it is uncertain if further exploration will result in the target being delineated as a mineral resource.(Tigris Uranium Corp., Press Release 7/26/2011).
Douglas H. Underhill, PhD, CPG, enCore’s Chief Geologist, is the Qualified Person as defined under National Instrument 43-101 and has reviewed and verified the information presented throughout this enCore Energy Corp. website.