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Butler Ranch

Project Highlights

Private mineral leases covering 2,592 acres
Hosts sandstone-type uranium deposits delineated by Conoco Inc. during the 1970s
Data for more than 2,000 drill holes in the vicinity that outlines considerable exploration potential
Located 75 miles north of the licensed Rosita Central Processing Facility, owned 100% by enCore

Project Details


The Butler Ranch project consists of private mineral leases covering 2,592 acres located 12 miles northeast of the town of Kenedy, Texas and 75 miles north of the Rosita Central Processing Facility (“CPP”). The project benefits from a well-developed infrastructure network including paved state and federal highways along with industrial grade electrical lines within close proximity.

The project is situated in the southwestern end of the Karnes County uranium mining district, which was one of the largest historic uranium production areas in Texas. Numerous open pit mines were developed and operated in the area, including important production operations by Conoco, Susquehanna-Western, Pioneer Nuclear, and Chevron Resources.

Historical mining activities in the project area focused upon deposits that were positioned above the water table, while enCore’s targets are situated below the water table where they may be amenable for ISR.

Mineral Resources

EnCore’s staff has not done sufficient work to classify the historical mineral resource estimates (reported below under Historical Exploration), as current mineral resources or mineral reserves. Further compilation of the historic geological and drilling data, resource modelling and possible confirmation drilling will be necessary to convert the historic estimates reported in the table below to NI 43-101 compliant resources/reserves.

Geology and Mineralization

The South Texas Uranium Province is an arcuate belt of sandstone-hosted uranium deposits that occur in clastic rocks ranging in age from Eocene to Miocene and Pliocene. The belt, which is 30 miles or more in width and more than 160 miles in length, parallels the present-day coast of the Gulf of Mexico.

Regionally, uranium mineralization is hosted in fluvial sandstones of the Eocene-age Jackson Group, the Oligocene/Miocene-age Catahoula Formation, Miocene-age Oakville Formation and Miocene/Pliocene-age Goliad Formation. Uranium deposits occur as “roll-fronts” in the more porous and permeable sandstones, and they have been localized by concentrations of organic plant debris in the sandstones, or where hydrocarbon gasses have migrated upward into the host rocks along high-angle faults.

Uranium mineralization at Butler Ranch occurs in the form of roll-front deposits hosted primarily in sandstones of the Jackson Group, including the Deweesville and Stones Switch units. Some mineralization in the area also occurs as tabular bodies associated with lignite (carbonaceous material) or in somewhat permeable units in the Conquista Clay.

Mineralization of interest at the Butler Ranch project occurs below the water table and is amenable to ISR. 

Historic Exploration

Previous exploration by operators including Conoco and Kerr-McGee totaled more than 2,000 drill holes, resulting in the delineation of several deposits within the vicinity of Butler Ranch. These drill programs were focused on identifying mineralization amenable to open pit mining and only delineated the portion of the mineralized trend minable by open pit.

In 2015, URI drilled five holes within one lease to test for extensions of an adjoining zone of uranium mineralization. All five drill holes encountered indications of uranium mineralization, which require further exploration.

URI reported a historic mineral resource on July 7, 2015 for the Butler Ranch project after a review of internal Conoco memorandums from 1977-1981.

Table 1 – Historical Mineral Resource Estimate for the Butler Ranch Project
CategoryTonsGrade eU3O8%U3O8 (lbs)

Under “Rules and Policies” of NI 43-101 Standards of Disclosure this mineral resource estimate must be reported as a Historical Resource Estimate. A qualified person has not done sufficient work for enCore to classify the historical estimate as a current mineral resource estimate. The Company does not treat this historical estimate as a current mineral resource estimate, and the estimate should not be relied upon.

The historic resources reported by URI, reference an unclassified category of estimated mineral resources. An accompanying technical report along with parameters and methods used to calculate the historic estimate are not available. In order to verify the historic estimate as current mineral resources a Qualified Person would need to complete a NI 43-101 report that includes review and verification of historic drilling.

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.