New Mexico

West Largo

Project Highlights

Project Details


The West Largo project consist of approximately 3,840 acres (i.e. six square miles) in McKinley County, New Mexico, along the north-central edge of the Grants Uranium District, approximately 25 miles north of Grants.

 The majority of the property is held through deeded mineral rights and also includes 75 unpatented lode claims. The property is located on six contiguous sections of land: 17, 19, 20, 21, 28 and 29, all within T15N, R10W. 

The West Largo Project is about 6 miles northwest of the westernmost deposits in the Ambrosia Lake District and about 5 miles east-northeast of the West Ranch area deposits. The project is accessed via New Mexico Highway 605 north from Grants, N. M. Highway 509 northwest from Ambrosia Lake and unimproved roads west from Highway 509.

Geology and Mineralization

The Jurassic age Morrison Formation Member hosting most of the sandstone-type uranium deposits in the Grants Mineral Belt, including the West Largo area, is the Westwater Canyon sandstone. Uranium mineralization is hosted in in at least five sand units, predominately in the A, B, C and E sands, and has been mapped for about 4.3 miles along a North 70° Westerly trend extending to about 500 feet in width. Uranium usually occurs as carnotite, coffinite, or other uranium oxides in grain interstices and is adsorbed to amorphous organic matter. While the bulk of the mineralization may potentially be extracted by conventional underground mining, it is reported a portion of the mineralization may also be amenable to ISR extraction.

Mineral Resources

There are no current Mineral Reserves or Mineral Resources on the West Largo property. Further compilation of the historic geological and drilling data, resource modelling and possible confirmation drilling will be necessary to convert the historic estimates outlined below to NI 43-101 compliant resources/reserves.

Historical Exploration

Gulf Minerals discovered uranium mineralization in the area in 1968. Subsequent drilling by

the major mining companies including Gulf, Kerr McGee, Pathfinder, and Santa Fe Minerals delineated the deposit on the West Largo properties in the 1970s and 1980s.

Table 1 – Historical Mineral Resource Estimate for the West Largo Uranium Property (80% of estimated resources used cutoff 6.0 ft @ 0.10% U3O8; the balance used lower cutoff)(1)
McKinley County, New Mexico
CategoryTonsGrade eU3O8%U3O8 (lbs)
  1. In 2011, Robert Maxwell, of Behre Dolbear & Company, (December 31, 2011) completed a technical report and mineral resource estimate for URI, based on results of 1,580 drill holes.  An estimate for the property was reported using, in part, a general outline method. Quantities of mineralized material were estimated using different parameters for cut-off grade and minimum mining intervals that were not always documented. The estimated uranium resource was formerly reported as ”Demonstrated” or “Probable”, Maxwell reports the Historical Mineral Resource as Indicated. The Inferred estimate is reported by Nakaoka, R., 1982, in Maxwell, December 31, 2011.

A 1982 report by Nakaoka states the resource estimate factored in a “disequilibrium” factor. His comparison of closed can and drill hole log radiometric equivalents with assay values resulted in “… an average [sic] variance of 126% to 136% in favor of the Chemical…” Maxwell reports it is unclear if the ratio represents a condition of secular disequilibrium or may include a log correction factor.

Under “Rules and Policies” of NI 43-101 Standards of Disclosure the mineral resource estimate in the report by Behre Dolbear 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.

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 website.