Sandstone-hosted roll-front uranium deposits with potential for in-situ recovery
(enCore’s Coal Hill Property is located adjacent to the Company’s 35-75 Property described in the previous 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 the previous section.)
- enCore owns a 100% interest in the 1,568 acre (634 ha) Property
- Covers uranium-bearing sandstones adjacent to and on trend with Cameco’s Smith Ranch ISR mine
- Located within the prolific Powder River Basin along with numerous other roll-front uranium deposits
The Coal Hill Property consists of 28 unpatented lode mining claims covering approximately 577 acres (233.5ha), located on privately owned surface lands with federal mineral rights. It is located 16 miles north of the town of Glenrock.
The Coal Hill Property covers mineralized stratigraphy along strike and adjacent to the Highland – Smith Ranch ISR facility and has the potential to host similar roll-front style uranium mineralization.
enCore Energy Corp. has purchased 100% interest in the property, which is subject to a 2% gross proceeds royalty (half of which may be repurchased for $200,000).
There are no current uranium resources or reserves on the Coal Hill Property.
Geology and Mineralization
(The Coal Hill Property is located adjacent to enCore’s 35-75 Property in the Powder River Basin as described in the previous section of this presentation. For related information the reader is referred to the: 35-75 Geology and Mineralization, as described in the previous section of this presentation.)
The Coal Hill Property is located within the southern Powder River Basin, on the western side of the basin axis. 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 Coal Hill 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.
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.
Previous uranium exploration in the area throughout the 1970s and 1980s included widespread drilling by companies such as Kerr McGee, Plateau Exploration, Pioneer Nuclear and Exxon.
During the life of the Dave Johnson coal mine (late 1960s until 2000), water well drilling intercepted two uranium roll-front gamma log signatures from the Fort Union sandstone. The coal mine did not follow up on these intercepts. The reclaimed mine site lies between the Coal Hill Property and the Smith Ranch – Highland Property.
The Smith Ranch – Highland ISR facility is located adjacent to Coal Hill on the east side. Owned by Cameco, this facility is the largest uranium producing ISR field in the United States. Cameco’s claims surround the Coal Hill claims to the east and south. The same stratigraphic section of ore-host rock units found on the Smith Ranch Property occur on the Coal Hill Property.
Limited exploration drilling for uranium has been conducted on the Coal Hill Property and the results of this exploration are unknown to enCore's management. Further research is ongoing to locate the drill logs and geological data for all water, oil, gas and uranium exploration drilling on the property.
Drill hole logs from several decades show that the sandstone hosting the uranium on the Cameco property can be traced in drill hole well logs on the eastern central parts of the Coal Hill claims.
The Wild Buck Property lies just north of the Coal Hill claims and is northwest of Smith Ranch. The Nuclear Exploration and Development Company drilled a number of strong mineral intercepts in the 1970s on this property. The Uranium One (formerly Energy Metals Corporation) Peterson Ranch project is located approximately fifteen miles southeast of the Coal Hill Property. Mineralization at Peterson Ranch has been defined in three major sandstone units of the upper Fort Union Formation (the Wasatch Formation has been removed by erosion at the Peterson Ranch site). This mineralization demonstrates that economic mineralization has been defined along strike for over fifteen miles on land adjacent to the eastern margin of Coal Hill.
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.