Great Panther Receives Upgraded Mineral Resource Estimate
posted on
Mar 19, 2008 02:59PM
Fastest growing primary silver producer in Mexico.
Great Panther Resources Limited TSX: GPR |
VANCOUVER, BRITISH COLUMBIA--(Marketwire - March 19, 2008) - GREAT PANTHER RESOURCES LIMITED (TSX:GPR) is pleased to announce that Wardrop Engineering (Wardrop) of Vancouver, B.C. has delivered an updated NI 43-101 compliant mineral resource estimate for the La Gloria / Las Palmitas Zones on the Company's Mapimi Project in northeastern Durango State, Mexico. The new estimate has effectively upgraded the previous resource of 22.3 million silver equivalent ounces (Ag Eq Oz) from the Inferred to the Indicated category and added an additional 6.3 million Ag Eq Oz in the Inferred category for a global resource of 28.6 million recoverable Ag Eq Oz.
The new estimate includes the twenty-nine core holes, representing 6,298 metres, completed during Great Panther's Phase I drilling program in the first half of 2007. This program consisted mostly of fill-in holes focused on the La Gloria Zone and adjacent Las Palmitas Zone in an effort to confirm, expand, and better delineate the previous Inferred Mineral Resource of 4,969,800 tonnes at a grade of 59g/t Ag, 0.13g/t Au, 0.81% Pb and 1.31% Zn estimated in 2006 by Wardrop from reverse circulation and core drilling of Coeur d'Alene Mines Corp., completed in 1997-98 (GPR news release, September 18, 2006).
The 2007 Phase I drilling at Mapimi has increased the confidence level of the resource, resulting in a new Indicated Mineral Resource estimated at 6,585,900 tonnes grading 28g/t silver, 0.09g/t gold, 0.41% lead and 1.14% Zn and an Inferred Mineral Resource at 2,027,900 tonnes grading 34g/t silver, 0.13g/t gold, 0.54% lead and 0.81% zinc. A breakdown of the resources by zone, type (oxide or sulphide) and category can be found in the tables below. The final report itself will be posted on the Company's website and on SEDAR once it is received from Wardrop (anticipated by early April).
In the new resource estimate, Wardrop has used different parameters than in 2006, such that the new estimate is considered to be more robust. In keeping with the previously reported resource estimate, Wardrop has applied a cut-off grade of 50g/t silver equivalent (Ag Eq). Metal prices and recoveries used were US$9.55/oz and 76%, respectively, for silver, US$530/oz and 70% for gold, US$0.63/lb and 80% for lead and US$1.00/lb and 80% for zinc. Statistically higher grade samples were also removed by capping the assay data at 150g/t for silver, 3.0g/t for gold, and 4.5% for each of lead and zinc. Wardrop used Ordinary Kriging and Inverse Distance Squared to estimate the resource, with blocks of 5m X 5m X 5m being used for the three-dimensional model. Metallurgical recoveries used are the same as for the 2006 resource estimate, which were based upon tests conducted by Silver Standard Resources Inc. in 1999 as part of a property review.
The new resource represents a total of 22,297,800 Ag Eq Oz in the Indicated category and 6,305,000 in the Inferred category. The uncapped resource would represent a total of 23,661,200 Ag Eq Oz in the Indicated category and 6,714,200 in the Inferred category. With the benefit of the added drill holes, Wardrop has reinterpreted the geological model of the mineralized zones and, while this has increased the confidence level, it has placed greater physical constraints on the model and, in particular, reduced the interpreted size of the Las Palmitas Zone.
The delay in releasing the updated resource estimate is due to the fact that, as part of the review process, it was found that while Great Panther's Phase I drilling compared favourably with the reverse circulation (RC) drilling completed by Coeur d'Alene, the latter's diamond drilling returned significantly higher silver and lead grades. This apparent inconsistency necessitated the re-assaying of some of the Coeur d'Alene drill core and a thorough check of all databases, statistics, calculations and interpretations. The Company is now satisfied that all assays are valid and that the difference in assay levels between drilling programs is due to the fact that the Coeur d'Alene diamond drill holes were mostly drilled into what is now interpreted as a higher grade core of the mineralized zone, while their RC holes and Great Panther's diamond drill holes were mostly drilled outside of this core, on a more systematic basis.
The effect of the higher commodity prices used in the current resource estimate compared to those used in 2006 is that lower grade material now becomes potentially economic, which thereby lowers the average grade of the resource while increasing the tonnage. Thus, the new resource represents an increase in tonnage of approximately 73% while the average grade of the Indicated and Inferred Resources is now 105g/t Ag Eq and 97g/t Ag Eq, respectively, compared to 139g/t Ag Eq in the 2006 resource. As such, the estimated recoverable ounces of silver equivalent have increased by approximately 28%.
Table 1: Resource Grades (Capped)
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ROCK GROUP GRADE GROUP Density Tonnage Au Ag Pb Zn Ag Eq
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tonnes/m3 g/t g/t (%) (%) g/t
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OXIDE INDICATED 2.48 4,272,400 0.09 32 0.46 0.95 99
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INFERRED 2.48 927,000 0.08 32 0.50 0.80 91
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SULFIDE INDICATED 2.66 2,313,400 0.11 22 0.30 1.50 118
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INFERRED 2.66 1,100,900 0.16 36 0.57 0.83 101
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TOTAL INDICATED 6,585,900 0.09 28 0.41 1.14 105
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TOTAL INFERRED 2,027,900 0.13 34 0.54 0.81 97
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Table 2: Contained Metal and Recoverable Ag Eq
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ROCK GROUP GRADE GROUP Tonnage Au Ag
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oz oz
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OXIDE INDICATED 4,272,400 12,036 4,349,036
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INFERRED 927,000 2,440 967,315
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SULFIDE INDICATED 2,313,400 7,794 1,652,527
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INFERRED 1,100,900 5,690 1,266,355
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TOTAL INDICATED 6,585,900 19,831 6,001,563
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TOTAL INFERRED 2,027,900 8,130 2,233,670
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ROCK GROUP Pb Zn Ag Eq Ag Eq
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lbs lbs grams ounces
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OXIDE 43,260,764 89,815,540 420,944,817 13,535,203
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10,269,078 16,257,856 84,707,530 2,723,715
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SULFIDE 15,542,659 76,382,524 272,518,009 8,762,637
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13,839,819 20,063,455 111,378,052 3,581,288
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TOTAL INDICATED 58,803,423 166,198,064 693,462,827 22,297,840
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TOTAL INFERRED 24,108,898 36,321,311 196,085,582 6,305,003
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