2010-12-17_REVISION - C1981019 (130)

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• Figure 2 -1: Comparison of Total Moisture by sampling campaign TS recommends a direct comparison between the seams analysed as part of the quality control for production and those same seams in the historic data. TS also recommends that the sample procedure be revised to either reduce the time between sampling and analysis or to better store the core to reduce moisture loss. The in situ moisture content of the coal is not easily determined from core samples. However, a reliable estimate is necessary in order to calculate the in situ relative density (RD) or Apparent Specific Gravity (ASG) for resource calculations and mine planning. TS experience with other lower rank bituminous thermal coals has found that the in situ moisture value is typically higher than the as received total moisture. 2.3.3 Coal Quality - Apparent Specific Gravity In coal, relative density varies with the condition of the analysis sample which, in turn, differs from the original condition of the coal in the ground. Therefore, for the determination of coal tonnages. TS recommends the density of the coal in situ is used in calculating tonnages from measured volumes. For the purposes of this example, TS has instead used laboratory as received ASG values, reduced to dry basis and plotted against dry ash (values above 70% ash were excluded). • There is an apparent correlation of 0.95. However this is misleading as there is an overestimation of ASG at very low ash contents, but an underestimation at higher ash contents (Figure 2.2), There are also clearly a high number of the same (low) ash values with varying ASG. Figure 2 -2: Dry Ash vs Dry ASG from recent Collom core analyses It is reasonable to expect a robust relationship between ash and relative density for a given • seam or seam group within a coalfield. Variation in this relationship due to rank and ash RIO 'f I lr'f O TS Ref: DRAFT Version: I a r „i,,,,,.,,i,,,,,.;.,, Y`� tt543 _ � • r• • �• f • Y JV ini t MASG Figure 2 -2: Dry Ash vs Dry ASG from recent Collom core analyses It is reasonable to expect a robust relationship between ash and relative density for a given • seam or seam group within a coalfield. Variation in this relationship due to rank and ash RIO 'f I lr'f O TS Ref: DRAFT Version: I a r „i,,,,,.,,i,,,,,.;.,, Y`� tt543 _ � • r• • �• f • Y t for a given • seam or seam group within a coalfield. Variation in this relationship due to rank and ash RIO 'f I lr'f O TS Ref: DRAFT Version: I a r „i,,,,,.,,i,,,,,.;.,,