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Gold Resource527 drill-holes comprising both RC and diamond core were incorporated in the modelled wireframes. Down-hole grade intervals were composited to 1m. High grades outliers were restricted in their influence, rather than applying a strict high-grade cut-off. The Yamarna mineralisation has been interpreted on section and wireframed (in Micromine), using a nominal 0.5g/t Au cut-off, by Eleckra geologists. A minimum of 1m down-hole width was used. The wireframes were further refined by Eleckra and independent resource consultants Ravensgate Minerals Industry Consultants. These wireframes formed the constraints for the block model constructed by Ravensgate. Parent block size for the block model was 2m x 10m x 5m. Block percentage coding was used to simulate sub-blocking. Because of the approximately 16km long mineralisation trends, the wireframes were split into 4 main areas: South (Attila), South-Central (Attila Nth), Central North (Alaric) and North Area (Khan North) based on breaks in the mineralisation. The same bulk density values depending on the oxidation state of the host rocks were used as in the 2002 estimation. Three surfaces were used to define four oxidation/weathering levels. Sample bulk density determinations were based upon values obtained from the measurement of 80 samples of diamond drill core. Ordinary Kriging was used for grade interpolations. Search ellipsoid parameters were: 80m x 40m x 20m (except for Northern Area: 80m x 60m x 20m). Three resource classes were defined, Measured, Indicated and Inferred, based on a combination of the data density (number of composites available for interpolation), spatial continuity (distance between block and composite) and Kriging variance. QAQC documentation has been derived mainly from the 2002 resource estimate. Gold intersections reported have been verified by previous project owners QAQC protocols, which include routinely inserted standards and duplicates. All drill samples were prepared by reputable laboratories and pulverised to 90% passing 75 microns. The majority of the RC and diamond core holes were analysed for gold using Fire Assay. The Mineral Resource inventory for the Yamarna Gold project as at 21 August 2008:
The Mineral Resource inventory for the Yamarna Gold project as at 21 August 2008. Note: rounding errors may occur. The current Mineral Resource estimate compares well with a 2002 estimate (at 1.00 g/t Au cut off) which stated figures of 12.6Mt at a grade of 1.82 g/t. Au. The total 2008 estimate has delivered a modest increase in ounces with respect to the previously published 2002 estimate of 740,000 ounces, due to the inclusion of the Khan North deposit which did not form part of the 2002 estimate, offset by the use of a more constrained model. A substantial (114%) increase occurred in the measured category due to infill drilling carried out by Eleckra since 2006. The new resource is based on a more constrained geological interpretation than the previous 2002 resource estimate. The 2002 resource estimates was based on unconstrained drill data using Multiple Indicator Kriging for interpolation using grades from 3m composites. The current model shows that the mineralisation is still open at depth and along strike. Due to the majority of the holes being shallow and further, because of large sections of the mineralised trend had been drilled on widely spaced lines, these potentially mineralised areas were not included in any resource category. As a result there is a potential to increase the resource by further systematic drilling. The results from both the previous and recent bottle roll metallurgical testwork show very good gold recoveries from all four deposits and all weathering profiles. The gold recoveries up to 98.0% can be achieved in fresh rock. |
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