|
Jambi The Jambi prospect comprises a prominent cone shaped hill which rises about 125m above the surrounding land surface. The host rocks are strongly altered and weathered basaltic volcanic rocks. Petrographic studies interpret two main stages of alteration both associated with incoming precious metal mineralization, comprising an early, neutral fluid quartz-adularia-illite alteration overprinted by a late stage, low temperature quartz-kaolin acid alteration event. Surface mapping and sampling by Finders indicates that the main gold mineralization occurs with a series of (oxidized) pyrite +/- quartz veinlet swarms, and quartz-pyrite cemented breccia zones, with a range of orientations but predominantly striking 015-025o and dipping about 80-85o to WNW. An apparent barren zone, trending NE, separates more silver rich mineralization to the south east from predominantly gold-rich to the north west; this is interpreted to be fault related. Two mineral resource estimates (summarized below) were published prior to Finders 2006 drilling campaign.
Summary of Jambi mineral resource estimates pre-2006 Antares’ TSX announcements (Antares, 1998) contain “preliminary resource” estimates for Jambi and previous press release (28 November, 1997) suggests that the gold equivalent is calculated using a 57:1 conversion. (i.e. 57 g/t Ag = 1 g/t Au). The estimates were reported in 1998 and, therefore, do not conform to the later NI43-101 Rules or Guidelines. There is no classification into Measured, Indicated and Inferred Mineral Resource and no Competent Person or Qualified Person is cited as having been responsible for the estimates. The results are included here purely as a historical record. H&S, in January 2006, independently reviewed the estimate. Domains outlining mineralisation were digitized from cross sections derived from a summary of drilling data from the 1986 and 1997-8 drilling programs. These outlines were used to estimate the extent of the mineralised envelopes and the resulting Inferred Mineral Resource estimate which used an assumed density of 2.6 and a simple cross sectional area method is regarded, given the uncertainties relating to Inferred Mineral Resources, as being broadly similar to the results of Antares. The results of the original assayed intervals were unavailable to Finders. H&S’s review was, therefore, based on Antares’ averaged assays over long intervals. In January 2007, H&S completed a further estimate for the Jambi deposit on the basis of Finders 3,900m drilling program in 2006 which comprised 34 new diamond drill holes plus data from 160 surface channel samples and supplemented by the historic data from an exploration adit and 95 drill holes for which only grades of mineralised intervals are available. Overall, a 175 metre by 125 metre area over the central part of the known deposit has been drill tested by Finders to around 150 metres below surface on a spacing of 50 by 50 metres with some irregularly spaced drilling on 25 metre intermediate sections. Gold and silver mineral resources were separately estimated by Multiple Indicator Kriging with block support correction to give estimates of recoverable gold mineral resources under assumptions regarding the degree of selectivity likely to apply to an open pit mining operation. This method of resource estimation contrasts with that previously reported by Finders in that it incorporates mining dilution and, from the experience of H&S, closely matches production. Mineral Resources were estimated in two passes. The first pass used only Finders 2006 data, panels not estimated during the first pass were estimated from a second pass which included both new and historical data. Two westerly dipping mineralised domains were defined to control estimation. It is likely, with further drilling and with a better understanding of the controls of mineralisation, that the definition of these domains will improve and lead to improved grade estimates. An attempt to re-model the resource using wire frame outlines considererd by Finders to better reflect the Jambi ore controls resulted in an estimate of less tonnes at a higher gold grade, but was deferred pending additional drilling data, as only two of the eight defined domains had sufficient data for reliable estimation. Due to the broad drill spacing relative to mineralisation continuity, the entire mineral resource estimate is classified as Inferred. Portions estimated by the first pass can be regarded as more accurate than those estimated by the second pass. Accurate estimation of the Jambi resource will require drilling the areas covered by historical drilling. Finders’ 2006 drill program was directed at fulfilling this aim. Rock density values of 2.1, 2.2 & 2.6 tonnes per cubic metre were used for the oxidised, partially oxidised and primary portions of the resource. These are based on 164 determinations. This compares with a constant value of 2.6 used in previous estimates. The lower density used for the oxidised zones represents an approximate drop of 20% in estimated tonnage. The majority of the estimated resources are oxidised with the proportion contributed by each oxidation class varying with cut off grade. At a 1.0 Au g/t cut off, 81% is oxidised, 17% is partially oxidised and 2% is fresh.
The mineral resource estimates are reported at cut-off grades which would span the range appropriate for open pit mining Significant figures used in the Table are intended to reflect the level of accuracy, and figures may exhibit rounding errors. The nature of the distribution at Jambi is such that significant additional drilling (to 25 x25m spacing) will be required to increase the confidence of the mineral resource estimate within the currently defined mineralisation domains.
Jambi Inferred Mineral Resource More drilling is required to test previously identified areas of surface mineralisation. For example, surface trenches sampled by previous explorers achieved mineralised lengths of 105 metres of 1.6 g/t Au, 50 metres of 0.5 g/t, 45 metres of 0.8 g/t, 20 metres of 0.9 g/t in areas well outside of the current Finders’ drilling. The mineral resource model as it now stands may not adequately model a high grade silver intercept of three metres of 3300 g/t from 77 metres in Finder’s drill hole BKJ22 with no nearby Finders drilling or previous holes with silver assays. This intersection appears to represent a different mineralisation style from the bulk of the currently defined Jambi resource and would require additional tightly spaced drilling to provide an accurate estimate of the high grade potential beneath the oxide resource.
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
