Underground drift bulk sampling of the Star resource comprised 66,545.09 tonnes from which 10,547.87 carats were recovered7. Underground bulk sampling data were used by P&E for Resource Estimation and, coupled with RE and LDD sampling, to derive LDD diamond damage adjustment factors.
Diamond grade and tonnage estimates were also derived from 103 LDD holes, of which 96 LDD holes reported diamond sampling data. Diamond sampling data consisted of 11,662.87 processed tonnes (19,977.59 in-situ tonnes) and 1,416.69 carats8 (Table 16.3). Based on a review of data supplied by Shore, P&E is of the opinion that the data are acceptable for Mineral Resource Estimation.
Avg Stones per
Avg Stone Size
(cpht) 9.4 10.2 6.0 0.6 2.9 8.8 7.5
tonne 0.64 1.02 0.99 0.11 0.45 0.97 0.82
cts/stone 0.15 0.10 0.06 0.05 0.06 0.11 0.09
P&E noted that the LJF, MJF and PPK units display distinct bimodal distributions for the LDD data (Figure 16.3). The observed bimodal distribution for the LDD data is largely a result of the grade differences associated with kimberlite sub-units (e.g. kimberlite breccia vs. pyroclastic kimberlite) and are not resolvable on the scale of the Star Kimberlite as a whole.
Table 16.3: LDD batch sample diamond data
CPK EJF Inner EJF Outer LJF MJF PPK TOTAL
44 409 105 92 91 40 781
LDD diamond frequency data for the CPK unit presents as the coarsest distribution, with LJF as the least coarse and the other kimberlite units intermediate between the two (Figure 16.4). Diamond frequency data for the UG samples in the EJF unit present as coarser than the LDD samples, suggesting preferential diamond damage and loss of larger stones during drilling (Figure 16.5). However, P&E noted that the smaller mass RE sample data present as coarser than the UG sample data. This is due to the presence of two +23 sieve stones in the RE sample data; removal of the stones from the RE data places the RE sample size frequency distribution intermediate between the UG and LDD samples. Shore geologists have reported that the RE samples contained an average of 30% kimberlite breccia, compared to 24% for the UG drift sampling.
7 Tonnages and carats utilized in the Mineral Resource Estimate differ from total tonnes sampled and total carats recovered as clean-up samples were not utilized in the Mineral Resource Estimate. In addition, the February 27, 2009 News Release mistakenly included batch 151 as a drift sample when it was actually a clean-up sample (443 tonnes and 49.7 carats). The previous Mineral Resource completed by AMEC on June 9, 2008 utilized 69,056 dry tonnes and 10,582 carats. The different tonnages and carats utilized are the result of the AMEC resource estimate totals including all clean-up batches except three which did not have results at time of the June 9, 2008 resource estimate.
Includes carats recovered in auditing process.
P&E Mining Consultants Inc. NI 43-101 Technical Report No 159 Shore Gold Inc. - Star Diamond Project Resource Estimate Update
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