VANCOUVER, BRITISH COLUMBIA--(Marketwire - May 17, 2011) - True North Gems Inc. (the "Company") (TSX VENTURE:TGX) is pleased to announce the completion of an initial mineral resource estimate for the Aappaluttoq Ruby and Pink Sapphire Project in Southwest Greenland. The Company currently holds two prospecting licenses covering 434 square kilometers.
This initial resource estimate was completed on only the Aappaluttoq discovery, one of several ruby discoveries on the property, and was prepared by EBA Engineering Consultants Ltd., a Tetra Tech Company, of Vancouver BC ("EBA") from 6470 m of drilling data and 100 tonnes of bulk sampling undertaken on the property over the last several years and uses recently updated geologic interpretations for the host zone lithology. The estimation of mineral resources and its classification is in accordance with CIM Estimation of Mineral Resources and Mineral Reserves Best Practices Guidelines and is prepared in accordance with NI 43-101 standards.
Highlights are as follows:
-- a total indicated mineral resource of 189,150 tonnes containing 59
million grams (296 million carats) of "Total Clean Corundum" (as defined
-- an additional inferred mineral resource of 21 million grams (109 million
carats) of Total Clean Corundum;
-- Geological interpretations demonstrate that the deposit is open to depth
and along strike.
Nicholas Houghton, President and CEO, commented: "Today's release is confirmation that the high grade ruby and pink sapphire enriched corundum discovered on surface at Aappaluttoq continues within an independently definable resource at depth and along strike. The indicated resource containing ruby and pink sapphire within Aappaluttoq will form the basis of our mine planning and preliminary feasibility evaluation, with expansion potential through the addition of about 109 million carats of inferred resource. This estimate does not include significant intersections of mineralization seen in the drill core below the level of the current resource, which offers future expansion possibilities."
Mineral Resource Estimate
The NI 43-101 compliant estimate of indicated and inferred mineral resources, summarized below, was compiled by EBA using data provided by the Company. EBA reviewed updated three dimensional geological interpretations of the mineralized zones (prepared primarily by the Company) and extensive project data collected since 2006. The mineral resource estimate comprises the integration of mineralization volumes, density, petrology and Total Clean Corundum content data obtained from diamond drilling and bulk sampling.
Average Contained Contained
Grade Average Corundum Corundum
Tonnes (2,3) Grade (2,3) (2,3,4)
Volume (1) (grams/ Grade(2,3,4) (grams x (carats x
(m3 x 1000) (x1000) tonne) (carats/tonne) 1,000,000) 1,000,000)
Indicated 59.1 189.1 313 1566 59.3 296
Inferred 24.1 77.2 283 1417 21.9 109
Resource categories comply with CIM standards on Mineral Resources and
Reserves. All numbers are rounded.
1. Densities are derived from specific gravity measurements of host
lithologies and estimated for host zone based on specific gravity of
corundum and average grade.
2. Based on a Total Clean Corundum grades greater than 1.7mm size fraction
from mineralogical lab analysis.
3. Top cut grade of 7,325 grams per tonne (97.5 percentile), and a lower
cut off grade of 1 gram per tonne.
4. One gram equals five carats.
Mineral resources that are not mineral reserves do not have demonstrated economic viability.
Tonnages and Grades
For the resource calculation, a 1m by 1m by 1m block model was created for tonnage and grade estimation using solid body geological models for the host zone, as revised by the Company and EBA. The block model was limited to a cut-off depth of 83 meters, and resource tonnages were derived using rock volumes reported from the block model and representative specific gravity measurements for each lithology. Geostatistics were used to assess top cut value of 7,325 grams per tonne (97.5 percentile of assay data) for the block model and interpolation and the host zone was constrained by geologic (lithological) modeling. Search ellipses for the interpolation profiles are based on geology and observed continuity of the phlogopite host zone. A lower cut off grade of 1 grams per tonne was selected from evaluation of grade tonnage relationship at several cut off grades.
The cut-off depth for the mineral resource categories were defined within each zone based on density of sample data and drill hole logs including lithology and the consistency of grade data within the geological models. Bulk samples taken at surface were used to provide discreet data points within the database, however the influence of this data is limited by the same parameters used for all other samples in the data base. Tonnage from the bulk samples has not been subtracted out of the resource.
All tonnages cited are for mineralized lithologies only. The block model was completed using Gemcom GEMS software and full details of the block model interpolation will be presented in the technical report currently being completed by EBA and the Company.
Drill density within the deposit is at a consistent collar spacing of 8 m centers, with fans of drillholes from each collar location at -45, -60 and -75 degree dips. Holes were drilled at an average azimuth of approximately 133 degrees intercepting the mineralized zone perpendicular to the strike direction of the host lithology.
Corundum resource grades are estimated for greater than +1.7 mm size fraction recovered after core sample preparation. This is nominally larger than the minimum size of gemstone rough that can be commercially polished, and which is consistent with the minimum sieve size used by the Company in valuations reported on January 16 and 17, 2008. No distinction has been made in the calculation for variations in quality (gem, near-gem and non-gem), size or colour of the recovered corundum. No work was done on the resource to evaluate the consistency or distribution of gem or near-gem quality, and non-gem corundum within the mineralized zone intersected by drilling because of the small volume of corundum recovered from each of the drill core intercepts.
However, the colour and quality distribution analysis of corundum and valuation of the sorted rough ruby and pink sapphire was completed on the larger bulk samples from surface. The variations of the colour and quality of corundum greatly influences the value of the Total Clean Corundum recovered. The value of sorted and recovered ruby and pink sapphire from the surface bulk samples are discussed in detail in the Company's technical report dated March 30, 2009 which is filed on SEDAR. Readers are encouraged to review this report to gain a complete understanding of valuation work done to date.
Geology Description & Mineralization
The Aappaluttoq ruby deposit is hosted within the Fiskanaessett Igneous Complex, an Archean (2.97Ga) layered mafic intrusion. The ruby and pink sapphire crystallised in a mafic metasomatic reaction zone between a chrome-rich ultramafic body and an aluminum rich gabbro. Subsequent cooling and retrograde metamorphism allowed the present phlogopite-rich zone to form as the main host-rock mineral to the ruby and pink sapphire mineralization. All of these units are now highly folded, but can be traced on a local and regional scale. The geological setting provides for a predictable location for the chrome-enriched corundum mineralization.
The deposit itself comprises a steeply dipping sheet or cone-like body which is currently drill defined over 100 meters laterally and to a depth of about 80m. However, ruby and pink sapphire intersections have been recorded in core down to a depth of about 200m below surface. The deposit remains open both at depth and along strike.
QA/QC & Assay Technique
Standard QA/QC techniques were employed throughout the life of this project. This includes strict chain-of-custody, tracking of shipment and parcel weights, security seals, insertion of blanks (both field and lab prepared) and the insertion of standards/spikes into the processing line. This program was completed under the supervision of both the project manager and the Company's Qualified Persons over the years. For 2007 drilling, whole core analysis was used, while for 2008 drilling the core was sawn and 1/4 of the core is retained by the Company.
As no standard procedures exist for assaying corundum from core, procedures were developed by the Company, EBA and engineers from the Saskatchewan Research Council ("SRC") in Saskatoon, SK - an ISO 17025 certified analytical laboratory. The objective of the assay procedures was to calculate a Total Clean Corundum grade for corundum over 1.7mm which could be related to grade and valuation work done for bulk samples taken in 2006 and 2007.
For preparation of the mineralized intersections in drill core, the first stages of the process occurred at SRC. Core was crushed into appropriate size fractions using a series of jaw crushers and high pressure grinding rolls. Matrix rock was separated through hand picking by trained mineralogists and subsequent gravity concentration using heavy liquid separation. The resulting concentrated corundum was then cleaned in hydrofluoric acid bath to remove silicate matrix left attached to the corundum crystals. Each sample was bagged individually, with sample weights recorded at every stage of the assay cycle. These samples were then shipped by SRC to the Company's secure laboratory in Vancouver.
Once each assay sample was logged at the Company laboratory, as varying amounts of matrix remained within the assay product, a photograph was taken and a visual estimate was completed on the individual assay bags which recorded the percentage of matrix remaining attached to the corundum crystals. A professional gemmologist then sieved each sample with a 1.7mm tyler mesh screen removing all undersize and then removed any +1.7mm non-corundum material. The resulting +1.7mm product (consisting of corundum and any remaining attached matrix) weights were recorded in the company central assay database. EBA then used this +1.7mm product weight and applied a corrective factor based on the visual estimate of matrix material remaining in the sample and the specific gravity of the corundum and the matrix. This resulted in a calculated "Total Clean Corundum" grade for +1.7mm corundum material which was used for the resource calculation.
Ruby and pink sapphire are variations of the mineral corundum, an aluminum oxide (Al2O3). When chromium invades the crystal structure of corundum, the chromium imparts a pink to intense pink or red coloration to the corundum. Intensely chrome saturated corundum is called ruby and less chrome saturated or pink corundum is called pink sapphire. For the purposes of the resource calculation all corundum recovered and cleaned that was greater than 1.7mm is included in the resource calculation as Total Clean Corundum. Thus Total Clean Corundum includes corundum of all colours and, due to the small size of the drill core intercepts, cannot practically distinguish between non-gem, near gem and gem ruby and pink sapphire recovered from core.
Specific gravity samples were taken across all rock types under the supervision of the Company's Qualified Person. Geostatistics were used to assess top cut value for the block model and interpolation. Because there were no specific gravity sample results available in host zone a compound specific gravity was estimated based upon the specific gravity value of the host rock (phlogopite and leucogratic gabbro) and the known specific gravity of corundum. Raw sample weights and weight of recovered corundum and average grade within the host zone was used to estimate a specific gravity for the mineralized host rock. This will result in a conservative estimation of density for any mineralized materials with above average grade. A top cut-off grade of 7325 grams per tonne Total Clean Corundum (97.5 percentile) was applied.
The Company will issue a NI 43-101 compliant technical report on the mineral resource at Aappaluttoq within 45 days as required. Concurrently, a pre-feasibility study ("PFS") is being prepared by EBA and by MT Hojgaard Engineering of Greenland and Denmark. This PFS will be based on the indicated resource set out above. This PFS will accompany an application for an exploitation (mining) license which is expected to be filed within the second quarter of 2011.
Qualified Persons for the NI 43-101 Report
Ms. Lara Reggin, P.Geo. (BC) of EBA is the independent Qualified Person responsible for the preparation of the mineral resource estimate, excluding valuation of gemstone material which has been completed by the Company. Ms. Reggin reviewed and approved the contents of this release.
EBA Engineering Consultants Inc., A Tetra Tech Company is a values-based consulting engineering and sciences company offering innovative and practical engineering, environmental and transportation solutions for the mining, energy, transportation and development sectors. EBA and Tetra Tech has over 3,500 employees in Canada and over 12,000 employees world-wide.
True North Gems Inc. is listed on the TSX Venture Exchange and is engaged in the exploration and development of Greenlandic and North American coloured gemstone prospects. The Company is a pioneer in coloured gemstone exploration and, currently in Greenland, has the rights to earn 100% interest in the Aappaluttoq ruby and pink sapphire project, holds a 100% interest in the Tsa da Glisza emerald property, Yukon, and the Beluga sapphire property located on Baffin Island, Nunavut. True North's prime focus remains the commercial advancement of the Aappaluttoq Ruby Project in Greenland.
The Company relies on litigation protection for "forward-looking" statements. The Aappaluttoq project does not yet have a mineral reserve and accordingly no economic evaluation has yet been done. Accordingly, investors are cautioned that, although management is proceeding with an exploitation (mining) permit application, the Aappaluttoq project may never achieve successful commercial production.The TSX Venture Exchange has not reviewed and does not accept responsibility for the adequacy or accuracy of the release.