Roughrider Doubles in Size as Hathor Confirms an Additional 30 M lbs at 11.58 % U3O8 for the East Zone

TSX-V: TAS          

VANCOUVER, May 17 /CNW/ - Terra Ventures Inc. (TSX-V: TAS) is pleased to provide an update on the Midwest Northeast Uranium property in which Terra owns a 10% production carried interest. In a press release dated May 17, 2011, Hathor reported:

"Hathor Exploration Limited (TSX:HAT) is pleased to announce the first mineral resource estimate for the East Zone of the Roughrider Uranium Deposit located in the Athabasca Basin, Saskatchewan. The estimate identifies 30 M lbs grading 11.58 % U3O8, and doubles the overall size of the Roughrider deposit, as currently defined.

Table 1 below shows the Mineral Resource Statement ("MRS") for the East Zone at the Roughrider Uranium Deposit, as determined by SRK Consulting (Canada) Inc ("SRK"), using the ordinary kriging (OK) method. Table 2 below lists the global model quantities using various cut-off grades. Table 3 shows the total resource for the Roughrider Uranium Deposit; this total does not include the recently discovered Far East Zone. Graph 1 is a grade tonnage curve, which in combination with Table 2, illustrate that the East Zone is relatively insensitive to cut off limits up to a value 1.00 % U3O8.

Table 1: Mineral Resource Statement for the East Zone, Roughrider Deposit, SRK Consulting *

Category Quantity Grade Contained
[Tonnes] U3O8 [%] As [%] Co [%] Cu [%] Mo [%] Ni [%] Se [ppm] U3O8 [million lb]
Total Inferred 118,000 11.58 0.02 0.01 0.86 0.10 0.02 26.65 30,130,000

* Mineral resources are not mineral reserves and do not have demonstrated economic viability. All figures are rounded to reflect the relative accuracy of the estimates. Reported at a cut-off of 0.4 percent U3O8 based on an underground mining scenario, metallurgical recovery of 98 percent, and metal prices of US$80.00 per pound of U3O8.

Table 2: Global Model Quantities and Grade Estimates,
East Zone, Roughrider Uranium Deposit *

Cut-Off Quantity Grade Contained
U3O8 [%] [tonnes] U3O8 [%] U3O8 [lb]
0.10 119,096 11.48 30,140,000
0.30 118,757 11.51 30,130,000
0.40 118,034 11.58 30,130,000
0.50 116,751 11.70 30,110,000
0.80 112,308 12.14 30,060,000
1.00 108,950 12.49 30,000,000
3.00 88,970 14.88 29,190,000

* 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.

Table 3: Total resources, Rougher Uranium Deposit

Mineral Zone Footnotes Category Quantity Grade Contained
      [Tonnes] U3O8 [%] U3O8 [million lb]
East  Zone 1,3,4 Total Inferred 118,000 11.58 30.130
West Zone 2,3,5 Total Indicated 394,200 1.98 17.207
West Zone 2,3,5 Total Inferred 43,600 11.03 10.602

1 Cut-off of 0.4 percent U3O8 based on an underground mining scenario, 2 Cut-off of 0.05 percent U3O8 based on an open pit, using all material above 200 m elevation, 3 Metallurgical recoveries of 98 percent and metal prices of US$80.00 per pound of U3O8 , 4 Disclosed in this news release, 5 Disclosed in news release dated Nov 29, 2010

Geological Framework

The East Zone is the middle of four zones currently identified at the Roughrider Uranium Deposit, as shown in Figure 1.

The resource model for East Zone was developed using data from 21 drill holes completed between September 2009 and September 2010 (Figure 2). The surface projection has a surface trace approximately 120 m long in a north-easterly direction, which corresponds to a down-dip length of approximately 125 m. The East Zone is a series of stacked, parallel lenses (>0.5 % U3O8) that collectively dip moderately to the north-east ( Figure 3). The mineral lenses are separated by intervals of weakly mineralized or non-mineralized rock (<0.05 % U3O8). The contacts between these zones are sharp. Unlike the West Zone, the mineral lenses are not uniformly mantled by a rim of low grade mineralization. As shown in Figure 3, there is abundant low grade mineralization intersected in drill core which is not included in the mineral lenses of the current resource model, and which represents additional resource potential.

As shown on the cross sections in Figure 4 and Figure 5, the lenses at East Zone span an aggregate thickness of up to 40 -- 50 m, with mineralization spanning a vertical extent of up to 80 - 100 m, starting at approximately 250 m depth from surface, and some 30-50 m below the unconformity.

As shown in the three dimensional model for the overall Roughrider Uranium deposit in Figure 6, the East Zone is positioned along-strike but slightly deeper than the West Zone. At East Zone, mineralization is hosted within basement rocks of both the Wollaston Group (pelitic gneisses, graphitic pelitic gneiss) and the Hanging Wall Wedge (granitic gneiss and granites). Overall, the Roughrider uranium system developed atop the Midwest Dome of Archean granitic gneiss, as shown in the 3-D model in Figure 7.

Mineral Resource Statement

The Mineral Resource Statement for Roughrider East Zone was constructed by SRK Consulting (Canada) Inc. A completed technical report prepared following Canadian Securities Administrators' National Instrument 43-101 will be available on SEDAR within 45 days of this News Release.

The boundaries for uranium mineralization were modelled by SRK based on Hathor sectional interpretations for seven high grade zones and wireframe grade shells generated with Leapfrog software by SRK. The Leapfrog grade shells where generated using a 0.5 % U3O8 threshold. SRK used both the Hathor interpretation and Leapfrog shells to generate a wireframe outline of uranium mineralization (>0.5 % U3O8). All interpreted sections strings were snapped to drill hole intersections where possible.

The database used to evaluate mineral resources for the Roughrider East Zone consists of twenty-one diamond drill holes completed between September 2009 and September 2010. The database comprises approximately 368 sample intervals assayed for U3O8 and other metals (including arsenic, cobalt, copper, molybdenum, nickel and selenium), and forty-six specific gravity measurements.

All assay intervals within the wireframe solids were composited to 0.5 metre to provide common support for analysis and estimation. Ninety one percent of all assays had sample lengths of 0.5 metres. SRK evaluated the impact of high grade composite 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 outliers are present in the database because high grades above the 95th to 98th percentiles for each resource domain are supported by adjacent composites or composites in nearby drill holes with grades ranging from 2.00 to 40.0 % U3O8.

Normal scores variograms were used to model the spatial distribution of U3O8. A single variogram was developed for the combined zones, as each zone contains too few composites for analysis. Variogram analysis was not conducted on potentially deleterious elements. There is insufficient specific gravity data for variogram analysis. The U3O8 variogram is orientated parallel to the general strike and dip-direction of the resource domains. Variogram model ranges (second structure) are 30m by 30m by 9m in the strike, dip direction and normal directions respectively. The U3O8 variogram model was assumed for the estimation of potentially deleterious elements and specific gravity excluding domains 4, 5 and 7.

Table 4. Summary of Variogram Model Parameters.

Variable Domain Zone C0 CC Model Rx [m] Ry [m] Rz [m] Datamine Rotation Comments
Z Axis Y Axis
U308% All All 0.20 0.15 Exponential 15 15 3 130 45 Normal Scores

A sub-blocked model was generated using Datamine Studio 3. The block model coordinates are based on the local UTM grid (NAD 83, Zone 13). The parent block size is 4.0 by 4.0 by 2.0 metres in the X, Y and Z directions respectively. The estimation strategy consists of estimating U3O8, potentially deleterious metals (arsenic, cobalt, copper, molybdenum, nickel and selenium) and specific gravity into a block model informed from composite data and constrained by seven resource domains. Specific gravity was not estimated for Domains 4, 5 and 7. Domains 4 and 5 have only two and four composites, respectively and specific gravity was not measured on core samples from domain 7.

U3O8 grades were estimated using three estimation runs using ordinary kriging informed from composite data from each domain, separately. The first estimation run is based on a search ellipse with ranges equal to the largest variogram model structure. The second run considers a search ellipse equal to twice the variogram ranges, while for the third estimation run the search ellipse was generally inflated to four times the variogram ranges. The bulk of blocks are estimated by the first run. The second and third estimation runs add only about ten and twelve percent more material, respectively to ensure that all blocks in the resource domains are estimated. Estimation of specific gravity using composites provides the most reasonable results maintaining the variability of the original composites. Specific gravity was estimated using an inverse distance function. For domain 4 the average of two specific gravity composites was (2.14) was assigned to all blocks of that domain. Blocks from domain 5 were all assigned as specific gravity value of 2.23, the only data available for that domain. The average of all specific gravity composites was assigned to all blocks for domain 7 (2.74). Only parent blocks were estimated. Sub-blocks were all assigned parent block values. Potentially deleterious elements (arsenic, cobalt, copper, molybdenum, nickel and selenium) were estimated using ordinary kriging. Variogram models for U3O8 were assumed for these metals. The same estimation parameters as U3O8 were used for estimating these elements.

Estimates were verified by conducting checks on Zone 2. 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 each zone. All validation checks confirm that the block estimates are appropriate and reflect the underlying borehole sampling data.

Mineral resources for the Roughrider Uranium East Zone have been classified according to the "CIM Definition Standards for Mineral Resources and Mineral Reserves" (December, 2005) by G. David Keller, P. Geo (APGO#1235) and Sébastien Bernier P.Geo. (APGO#1847) both "independent qualified person" as defined by National Instrument 43-101. After review, SRK considers that all modelled blocks in the Roughrider East Zone should be classified as Inferred within the meaning of CIM definitions because the confidence in the estimates is insufficient to allow the meaningful application of technical and economic parameters or to enable an evaluation of economic viability worthy of public disclosure and justify an Indicated classification. Additional infill drilling and sampling is required to support a higher classification. It cannot be assumed that all or any part of an Inferred mineral resource will be upgraded to an Indicated or Measured mineral resource as a result of continued exploration.

Midwest Northeast Property

The Midwest Northeast Property is within the main uranium-producing eastern corridor of the Athabasca Basin. The Property comprises 3 mineral leases covering 543 ha. Infrastructure is excellent. The Property is connected to Highway 955 by a 6 km winter road. The property is 8.5 km north of the community of Points North and the Points North commercial airport, the main service hub for northeastern Saskatchewan. The Property is within 25 km of operating uranium mine, mill and tailings facilities established at Rabbit Lake and McClean Lake during the past 35 years of production in the Athabasca.

Terra Ventures Inc. owns a qualified 10% interest in the largest claim on the Property, carried to the completion of a positive feasibility study and announcement of intent for commercial production. Terra and Hathor recently announced (May 9, 2011) a definitive Plan of Arrangement, which remains subject to a number of conditions including, but not limited to, receipt of all regulatory, court and shareholder approvals, and will result in consolidation of 100% ownership of the Roughrider uranium deposit.

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

Terra Ventures is a junior exploration company focused on acquiring and developing quality uranium projects which have world class potential. The Company is dedicated to building shareholder value by acquiring strategic uranium properties in this period of strengthening global demand for uranium supply. The Company's combination of strategic land positions, prospective exploration projects and no risk carried interest projects - combined with technical expertise and management's fundraising ability - are the foundation for growth in the uranium business.

On behalf of the board of directors of


"Gunther Roehlig"

Gunther Roehlig, President

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 news release.

This News Release contains forward-looking statements. Forward-looking statements are statements which relate to future events. In some cases, you can identify forward-looking statements by terminology such as "may", "should", "expects", "plans", "anticipates", "believes", "estimates", "predicts", "potential" or "continue" or the negative of these terms or other comparable terminology. These statements are only predictions and involve known and unknown risks, uncertainties and other factors that may cause our or our industry's actual results, levels of activity, performance or achievements to be materially different from any future results, levels of activity, performance or achievements expressed or implied by these forward-looking statements. While these forward-looking statements, and any assumptions upon which they are based, are made in good faith and reflect our current judgment regarding the direction of our business, actual results will almost always vary, sometimes materially, from any estimates, predictions, projections, assumptions or other future performance suggested herein. Except as required by applicable law, the Company does not intend to update any of the forward-looking statements to conform these statements to actual results.


SOURCE Terra Ventures Inc.

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For further particulars about Terra Ventures, please contact Ryan Johnson, Investor Relations, at 1-866-683-0911 or visit the Company's website at

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