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<br />elevation of 4810 feet above mean sea level. This line is of course the 4810 foot structural contour line <br />on each seam. <br />Thickness values for each seam (interpreted drill hole geophysical logs and core analysis) were posted <br />at ea<:h drill hole location on individual seam maps and were the basis for the "coal reserve base" <br />' estimate. Isopach maps for each seam were then constructed based on the posted thickness values. <br />Reserves were estimated for each seam by planimetering the azeas of different thickness delineated by <br />' the isopach lines. <br />' The high incidence of partings and splits in the Deserado Mine area coal seams presented some <br />problE;ms in delineating coal seam thickness. As an example, a drill hole log showing an interval of <br />seven (7) feet consisting of two (2) feet of coal, three (3) feet of parting, and two (2) feet of coal can <br />' be interpreted as a seam of coal seven (7) feet thick with a three (3) foot parting or as two sepazate <br />seams. with three (3) feet of interburden. In the first case, the seven (~ feet would over-state reserve <br />estimates because it would include three (3) feet of non-coal material. The second case would result <br />' in no coal reserve estimate because neither of the two coal seams could meet the 28 inch minimum <br />thickness criteria to be included in the "coal reserve base" estimate. To solve this problem and provide <br />' a consistent method by which the "coal reserve base" is estimated, a ratio of 3:1 coal thickness to <br />parting thickness was used. If the ratio of coal thickness to parting thickness was equal to or Beater <br />than .I:1, the parting thickness was included. If this ratio was less than 3:1 then individual coal splits <br />would have to meet the minimum thickness criteria of 28 inches to be included for the estimate. In the <br />event that logs or core showed there were multiple splits to an individual seam (that qualified for the <br />' estim:ite) then the thickness of the qualifying splits would be added together to provide a net coal <br />thickness at that particular location. The net coal thickness value would therefore replace an individual <br />seam thickness value. <br />Boundaries used for estimating the "coal reserve base" included the Federal coal lease boundaries and <br />the individual seam outcrop. In addition, the lease stipulations for Federal coal lease C-0126669 <br />prohit~it the mining of coal within 100 feet of the 100 year flood plain of the White River. This azea <br />of C-0126669 was not included in the "coal reserve base". Relative to the D Seam, the area of the old <br />' abandoned Staley-Gordon coal mine was also excluded from the "coal reserve base" estimate. <br />' Table 4-4 is a summary by lease and by seam of the Deserado Mine Logical Mining Unit "coal reserve <br />base". <br /> <br />29 <br />1 <br />