With enCore’s acquisition of the Juan Tafoya property through its purchase of Westwater’s assets, the Company has consolidated the property with its wholly owned Marquez property to comprise the largest uranium deposit in the eastern Grants Uranium District.
The Marquez property is located in McKinley and Sandoval Counties, New Mexico, along the eastern margin of the Grants Uranium District, approximately 20 miles (32 km) north of the town of Laguna. enCore controls the mineral right through private land leases totaling 18,596 acres (7,524 ha).
The property was extensively explored by Kerr McGee Corp. and Bokum Resources Corporation during the 1970-80s, with more than 944 holes drilled. Kerr McGee was a major uranium miner and producer in the Grants District during this period.
Following completion of a Pre-Feasibility study and mine planning, in 1978 Kerr McGee sold 50% of the project to joint venture partner Tennessee Valley Authority. The joint venture elected to pursue underground mining operations by the mid-1980s. However, with falling uranium prices, the mine plan was shelved and the property was returned to the lease holders in the late 1980s.
There are no current Mineral Reserves or Mineral Resources on the Marquez Property. enCore Energy Corp. 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 outlined below to NI 43-101 compliant resources/reserves.
Geology and Mineralization
The Jurassic age Morrison Formation Member hosting most of the sandstone-type uranium deposits in the Grants Mineral Belt, including both the Marquez and the Juan Tafoya deposits, is the Westwater Canyon sandstone, primarily designated as the lower two C and D sand units on the Marquez property and as the Middle and Lower sand units on the Juan Tafoya property. The uranium mineralization on both properties occurs primarily as the tabular-type, however lesser amounts of roll-type mineralization are also reported.
|Table 1 – Historical Mineral Resource Estimate for the Juan Tafoya – Marquez Project(1)(2)|
|McKinley and Sandoval Counties, New Mexico|
|Category||Tons||Grade eU3O8%||U3O8 (lbs)|
- On June 10, 2010, Strathmore Minerals Corp filed the “Marquez Uranium Property, McKinley and Sandoval Counties, New Mexico, National Instrument 43-101 Mineral Resource Report”, prepared by M. Hassan Alief, QP, on SEDAR. Of the 384 holes drilled in the Marquez Canyon area, radiometric logs from 150 holes were used in making the uranium mineral resource estimate. The estimate for the property was made using a polygonal estimation methodology based on gamma logs from 140 holes drilled on the property by Kerr McGee Corp., and 10 holes by Bokum Resources. The deposit is located on the McKinley County portion of the Marquez Property. The estimate was reported an measured resource of 998,625 tons containing 2,512,301 pounds of U3O8 with an average grade of 0.126%, an indicated resource of 2,611,584 tons containing 6,618,042 pounds of U3O8 with an average grade of 0.127% and an inferred resource of 2,159,520 tons containing 4,906,695 pounds of U3O8 with an average grade of 0.114%.
- On May 15, 2014, Broad Oak Associates completed a report entitled “NI 43-101 Technical Report on Mineral Resources: Juan Tafoya Uranium Project, Cibola, McKinley and Sandoval Counties, New Mexico USA”. An estimate for the property was made using the Inverse Distance Squared method using a cut-off grade of 0.08% eU3O8 and incorporated a drill database including 239 holes. The estimate combines the Marquez and adjacent Southeast deposits and was estimated to host an inferred resource of 6,509,300 tons containing 15,305,900 pounds of U3O8 with an average grade of 0.117%.
Under “Rules and Policies” of NI 43-101 Standards of Disclosure the mineral resource estimates 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.
Figure 1. Property area prior to the recent transaction with Westwater Resources
Source: Alief, M. Hassan, Alinco Geoservices, Inc., June 10, 2010, “Marquez Uranium Property, McKinley and Sandoval Counties, New Mexico, NI 43-101 Mineral Resource Report
Prepared For Strathmore Minerals Corp., p. 28.
Figure 2. Property area acquired through the recent transaction with Westwater Resources
Source: Carter, G.S., Broad Oak Associates, May 15, 2014, “NI 43-101 Technical Report on Mineral Resources: Juan Tafoya Uranium Project, Cibola, McKinley and Sandoval Counties, New Mexico USA”, for URI., p. 31.
A cross-section C-C’ along the southeasterly portion of the Marquez deposit is shown below.
Figure 3. Representative cross section through the Marquez Uranium Deposit.
Source: M. Hassan Alief, June 10, 2010, Technical Report on the Marquez Uranium Property, Report prepared for Strathmore Minerals Corp.
The Strathmore report also indicates that during Kerr McGee’s historical evaluation of the property it conducted studies of Chemical Disequilibrium of the Marquez uranium mineralization. The studies were conducted based on chemical analysis of drill core to assess the state of equilibrium between estimates of uranium from gamma logs and results of chemical analysis of the corresponding core samples.
Overall, the analyses of the seven core holes resulted in a positive disequilibrium ranging from 1.17 to 1.55 chemU3O8/eU3O8. While these results suggest that the Historical Mineral Resource Estimates shown above may underestimate the uranium resource, no adjustments in uranium grade were made to take into account these positive results and an equilibrium state of one was assumed.
URI’s staff prepared mineral resource estimates for the Marquez and Southeast deposits utilizing the extensive historical geological, gamma-ray, and geochemical information that was generated by Bokum Resources’ drilling program. The resource estimates were made using a three-dimensional block model employing the “Inverse Distance Squared” interpolation method. A 0.04% eU3O8 mineralized boundary was used to constrain the block model.
The mineral resources estimated for the Marquez and Southeast deposits are classed in the “Inferred” category by Carter, (May 15, 2014), and are considered to be compliant with the CIM Code, as outlined by the Canadian Institute of Mining, Metallurgy and Petroleum “CIM Standards on Mineral Resources and Reserves, Definitions and Guidelines” (CIM, 2010).
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.