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Coal Quality Data Review for Colowyo Coal Company <br />C] <br />drill hole data east of coordinate E1,340,000 and north of coordinate <br />N332,000. The Collom Area included drill hole data west of coordinate <br />E1,336,000 and north of coordinate N340,000. HGC restricted the Collom <br />Area in this fashion to exclude the Consol Danforth Hills data from the <br />analysis. <br />In the analyses, HGC differentiated the Mine Area drill hole data from the <br />active mining production data. The Mine Area drill hole data is defined "Mine <br />Area DH" on most of the charts and tables. <br />HGC used the July 15, 2004 "Last Pass" quality data to provide a snapshot of <br />currently coal quality at Colowyo. <br />2.1 Discussion of Base Coal Quality Data <br />• While performing a review of the full proximate data within the database, <br />HGC determined that the Excel databases of the coal quality data contained <br />data points that had been adjusted. Specifically, the moisture values of the <br />Utah International (Utah) drill holes contained a +2% moisture adjustment. <br />The adjusted moisture values of the Utah drill hole data were correctly <br />applied to the ash, sulfur and Btu /lb values. However, the volatile matter <br />and fixed carbon data of these data were not adjusted. Therefore the <br />database contained proximate values of different moistures than the Excel <br />databases. <br />To ensure that future studies of the Colowyo drill hole data begin with raw, <br />unaltered data, HGC factored the 2% moisture out of the Utah drill holes to <br />arrive at raw, dry basis coal quality data for storage in the Colowyo Drill Hole <br />Database„ HGC checked the analyses of two complete drill hole files to <br />ensure that the values within the database matched the paper copies. Every <br />• sample checked matched exactly. <br />July 2004 Page 5 of 16 <br />