Hathor Exploration Limited

Hathor Exploration Limited

November 30, 2010 08:01 ET

Hathor Upgrades Mineral Resource Estimate for Roughrider Uranium Deposit to 28 M lbs U3O8, Including High Grade Zone of 24 M lbs at 11.7% U3O8

VANCOUVER, BRITISH COLUMBIA--(Marketwire - Nov. 30, 2010) - Hathor Exploration Limited (TSX VENTURE:HAT) is pleased to announce the updated and upgraded mineral resource estimate for the Roughrider Uranium Deposit located on its Midwest NorthEast property, Athabasca Basin, Saskatchewan. Details are provided below in Table 1. Other attributes of the Roughrider uranium deposit include:

  • Approximately 60% of the mineral resource is in the Indicated category.

  • Conceptual Whittle pit optimization indicates 99% of the mineral resource is amenable to open pit extraction. 

  • Metallurgical extraction recoveries of 98% have been reported previously for the Roughrider deposit (see News Release dated June 16, 2010).

  • Low As (arsenic) levels are confirmed.

  • Average depth to the top of the deposit is approximately 215 m. 

  • Nearly all mineralization is located within basement rock.

This mineral resource estimate does not include Roughrider East. It is located 200 m east along strike. Once final assays for summer drilling at Roughrider East are received, geological models will be developed and preliminary resource models will be evaluated. Roughrider East represents further significant upside for the overall resource potential of the project. 

Table 1 below shows the Mineral Resource Statement ("MRS") for Roughrider as determined by SRK Consulting (Canada) Inc. ("SRK") based on an ordinary kriging (OK) estimate. 

Table 1: Mineral Resource Statement* for the Roughrider Uranium Project, Saskatchewan, SRK Consulting, November 29, 2010.

Category Quantity Grade Contained
    U3O8 As Co Cu Mo Ni U3O8
  [Tonnes] [%] [%] [%] [%] [%] [%] [million lb]
Indicated High Grade Zone 58,200 10.68 0.17 0.03 0.41 0.22 0.15 13.703
Inferred High Grade Zone 36,600 13.07 0.69 0.10 0.57 0.26 0.55 10.546
Indicated Low Grade Zone 336,000 0.48 0.00 0.00 0.00 0.00 0.00 3.556
Inferred Low Grade Zone 7,000 0.31 0.00 0.00 0.00 0.00 0.00 0.048
Indicated Total 394,200 1.98 0.03 0.00 0.06 0.03 0.02 17.207
Inferred Total 43,600 11.03 0.58 0.08 0.48 0.22 0.47 10.602
* Mineral resources are not mineral reserves and do not have demonstrated economic viability. All figures have been rounded to reflect the relative accuracy of the estimates. Reported at a cut-off of 0.05 % U3O8 above 200 m elevation and within the Roughrider property owned by Hathor. "Reasonable prospect for economic extraction" assumes open pit extraction, metallurgical recovery of 98 %, and metal prices of US$80.00 per pound of U3O8.
Less than 1 ppm

Table 2 on the following page provides a comparison, or sensitivity analysis, for the Roughrider estimates by using the inverse distance squared (ID2) interpolation. The similarity of results underscores the robustness of the drill hole and assay data base for Roughrider, and the continuity (predictability) of high grade mineralization at Roughrider. 

Table 2: Global Model Quantities and Grade Estimates*, Roughrider Uranium Project.

    Ordinary Kriging Inverse Distance Squared
Cut-off Quantity Grade Contained Grade Contained
U3O8[%] [t] U3O8[%] U3O8[lb] U3O8[%] U3O8[lb]
0.00 404,431 1.93 17,207,000 2.01 17,920,000
0.05 394,200 1.98 17,207,000 2.06 17,903,000
0.10 371,400 2.10 17,195,000 2.18 17,850,000
0.50 158,100 4.55 15,859,000 4.76 16,591,000
1.00 85,200 7.87 14,783,000 8.28 15,553,000
2.00 64,600 9.96 14,185,000 10.49 14,940,000
3.00 55,000 11.27 13,655,000 11.89 14,406,000
0.00 43,600 11.02 10,593,000 11.82 11,362,000
0.05 43,600 11.03 10,602,000 11.82 11,362,000
0.10 42,800 11.23 10,596,000 12.03 11,351,000
0.50 37,700 12.71 10,564,000 13.63 11,328,000
1.00 36,000 13.26 10,524,000 14.23 11,294,000
2.00 34,700 13.71 10,488,000 14.73 11,268,000
3.00 32,200 14.57 10,343,000 15.7 11,145,000
* The reader is cautioned that the figures in this table should not be misconstrued with a Mineral Resource Statement. The figures are only presented to show the sensitivity of the block model estimates to the selection of cut-off grade.

The exploration database for Roughrider is robust. It is based on based on 174 drill holes exceeding 60,000 m completed in five successive summer and winter drill programs starting in 2008 (Figure 1). Drill hole separation varies from less than 10 m in the core zone to approximately 25 m elsewhere in the deposit (Figure 2). The Roughrider data base includes 24,300 sample intervals assayed for U3O8 and other metals (including arsenic, cobalt, copper, molybdenum, and nickel), and more than 420 bulk dry density measurements obtained in the field. 

Roughrider uranium deposit is a robust, high grade uranium system. 
As shown on Figure 3, the major attributes of the deposit are concordant and predictable, including: 1) the alteration envelope; 2) mineral deposit outline (120 ppm U3O8); 3) outer low grade mineral resource shell (0.05% to 3% U3O8), and; 4) high grade core zone with grade greater than 3% U3O8. All attributes have a long axis of approximately 080° to 090° azimuth, with a moderate dip (30° to 40°) to the north. In plan view, the deposit is up to 220 m in length and 100 m in width. In section view, the mineral zones span a thickness of up to 55-60 m. The following data highlight the strength and continuity of mineralization at Roughrider:

  • High grade mineralization intersected and delineated on virtually all twenty cross-sections spaced 10 m apart along the entire 200 m length of the deposit.

  • 618 chemical assays over 3.0 % U3O8.

  • 7,000 chemical assays over 0.05 % U3O8.

  • Bulk dry densities of mineralized rock range from 1.74 to 5.51 g/cc.

  • Wireframe models outline eleven high grade wireframes and four low grade wireframes. All high grade domains are contained in one main low grade wireframe solid (Zone 100).

Figure 4 is a grade/tonnage plot which shows the similarity of resource estimates using ID2 and OK interpolations. As such, Table 2 and Figure 4 reinforce that mineral resource estimation for the Roughrider deposit is not sensitive to analytical approach.

Mineral Resource Statement

The Mineral Resource Statement for Roughrider was constructed by SRK Consulting (Canada) Inc. A completed technical report prepared following Canadian Securities Administrators' National Instrument 43-101 and Form 43-101F1 guidelines is anticipated for early January, and will be available on SEDAR within 45 days of this News Release.

The boundaries for uranium mineralization were modelled by SRK using a preliminary Hathor interpretation of high and low grade domains, and wireframe grade shells generated with LeapFrog software. The Leapfrog grade shells were generated using a three percent U3O8 thresholds for the high grade domain and a 0.10 to 0.05% threshold for the low grade domain. SRK used both the Hathor interpretation and Leapfrog shells to generate a wireframe outline of high and low grade uranium mineralization on vertical sections spaced by 5 to 10 m. SRK generated eleven high grade wireframes and four low grade wireframes that were considered for geostatistical analysis, variography and grade estimation. 

The database considered for resource estimation consists of 149 drill holes comprising approximately 24,300 sample intervals with chemical assays for U3O8 and other metals (including arsenic, cobalt, copper, molybdenum, and nickel) and approximately 420 specific gravity measurements. All assay intervals within the high grade and low grade wireframe solids were composited to 0.5 m to provide common support for analysis and estimation. SRK evaluated impact of high grade outliers in each zone using cumulative probability plots, histograms and examining the spatial distribution of higher grades with respect to other drill holes and adjacent composites. SRK concludes that no significant assay outliers are present in the database, thus no grade capping of assays was applied.

Variogram model radii for resource estimation were restricted to 20x20x2 m for the high grade zones and 20x15x15 m for the low grade zone. A sub-blocked model for the Roughrider project was generated using Datamine Studio 3. The block model coordinates are based on the local UTM coordinate grid (NAD 83, Zone 13). The parent block size is 4 by 4 by 2 m and is sub-blocked to 1.0 m in the X and Y directions and 0.002 m in the Z direction. 

The estimation strategy for the Roughrider deposit consists of estimating U3O8 and other elements, and specific gravity into a block model informed from composited data and constrained by fifteen resource domains. Uranium oxide (U3O8) grades were estimated using three estimation runs. The first estimation run is based on a search ellipse with ranges equal to the largest variogram model structure the second run consists of a search ellipse range equal to twice the variogram range. The third estimation ellipse consist of a search ellipse generally three times the search ellipse range. The bulk of blocks are estimated in the first run. Second and third estimation runs adds only about 18 and 9% more material, respectively. 

SRK tested four estimation methods for density to ensure that the variability in the data set can be approximately replicated in the estimate. The three estimation methods used are:

  • Moving average using a 30 m sphere for averaging;

  • Global kriging of entire composite data set for each zone as well as all each data set for high and low grade domains, using ordinary kriging;

  • Direct estimation of specific gravity composites using ordinary kriging; and

  • Estimation of the product of specific gravity and U3O8 composites using ordinary kriging, followed by dividing the estimated product by estimated U3O8 grade.

An examination of density estimates results by Hathor and SRK indicates that the direct estimation of specific gravity composites appears to produce the most reasonable results maintaining the variability of the original composites. Global kriging is the next best result. Potentially deleterious elements arsenic, cobalt, copper, molybdenum, and nickel were estimated using ordinary kriging. Variogram models for U3O8 were assumed for these metals. Estimates were verified by conducting checks on Zones 5 and 100. Verification procedures included visual examination of block grades to drill hole composites, and comparing estimated grades at zero cut-off to nearest neighbour estimates and declustered means for the two zones. All validation checks confirm that the block estimates are appropriate and reflect the underlying borehole sampling data. 

All block model estimates were full block estimates with full block values assigned to sub-blocks.

Mineral Resources for the Roughrider uranium project have been classified according to the "CIM Standards on Mineral Resources and Reserves: Definition and Guidelines" (December, 2005), by G. David Keller, P. Geo (APGO#1235) an "independent qualified person" as defined by National Instrument 43-101, who has reviewed the technical aspects of this News Release related to the Resource Estimate. Resource classification criteria include drilling density, variography results and estimation run. All blocks in Zone 100 are classified as Indicated because this zone is well informed by drilling spaced at 5 to 10 m and blocks were estimated with U3O8 grades entirely by the first estimation run. Zone 5 is also well informed by data spaced from 5 to 10 m with the exception of the extreme northwest portion of the Zone which is not well informed by drilling. This area was manually assigned an Inferred classification. Zone 2 was classified according to estimation run; first estimation run estimates was classified as Indicated with all other blocks classified as Inferred. All other zones were classified as Inferred because they are informed by limited data. 

Midwest Northeast Property

The Midwest NorthEast Property is well located in the northeastern Athabasca Basin, accessed by a 6 km winter road from Highway 955. The property is 8.5 km north of the community of Points North, the main service hub for northereastern Saskatchewan. It is within 25 km of operating uranium mine, mill and tailings facilities established in the northeast part of the Basin during the past 35 years. 

Terra Ventures Inc. owns a qualified 10% interest on the Property, carried to the completion of a positive feasibility study on the Roughrider Deposit.

Alistair McCready, Ph.D., P.Geo., Hathor's Exploration Manager with responsibility for all of Hathor's exploration in Saskatchewan, and Michael Gunning, Ph.D., P.Geo, Hathor's Chief Operating Officer, are Qualified Persons as defined by National Instrument 43-101 and have reviewed and approved the technical disclosure contained in this news release. 

Stephen G. Stanley, President & CEO

Hathor Exploration Limited

Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.

Contact Information

  • Hathor Exploration Limited
    Tony Nunziata
    Hathor Exploration Limited
    Kelsea Murray