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iii iiiiiiiiiiiuiii <br /> STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Depanmem of Natural Resources <br />1 J 1 3 Sherman 51 . Room 215 <br /> <br />Denver, Colorado 80203 II~ <br />Phone. IJ031 86fi-7567 <br />FAX:110J183L8106 <br /> DEPARTMEIJT OI <br /> NATURAL <br /> RESOURCE <br /> Roy Romer <br /> Governor <br />April 25 <br />1997 <br />, IamesS luihheaJ <br /> E ~emu.c Uim~ ini <br /> Mi~hnrl8 Long <br /> Urv~sion Dne~w~ <br />Mr. Lary Reschke <br />Powderhom Coal Company <br />P.O. Box 1430 <br />Palisade, CO 81526 <br />RE: Roadside North & South Portal Mine (C-81-041) <br />Midterm Bond Calculations <br />Dear Mr. Reschke, <br />The Division received the disk containing ACAD R-12 file of the existing and proposed final <br />contours at the Roadside South Portal Mine. The Division evaluated the maps and the material <br />balance using SurvCADD, a software package developed by Carlson Software. <br />A 3D polyline perimeter was drawn around the postmining topography representing the limits of <br />the earthwork and the daylign[ point where the cuts and fills tie to the original ground. The <br />perimeter was drawn as a distinct layer and made a pan of both existing and final surfaces. <br />Volumes were then determined from the layers and the inclusion perimeter. The Division came <br />up with 133, l45 CY of cut material and 129,446 CY of fill material. These numbers compare to <br />Powderhorn's estimate of 138,000 cy of cu[ and 146,800 cy of fill. See attached report for <br />further detail. <br />The Division located a number of data errors in the postmining map generated by Powderhom. <br />The data errors included a series of contour intervals labeled 4,790 located adjacent to the <br />regraded refuse pile. The Division deleted these lines to determine a more precise cut and fill <br />balance. <br />The Division is satisfied [hat the cut and fill material at the South Portal Mine will balance when <br />the site is reclaimed. The difference between the cut and fill volume is less than 4,000 cy of <br />material, a relatively small margin of error. Exhibits 6C and 26 do not need to be revised to <br />account for any discrepency in the material balance. <br /> <br />