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<br />M03107GE <br />• The cross sections included in our stability analyses are C-C for <br />the Coal Processing Facility site cut slope and section D-D for the <br />material storage area and haul road fill slope as presented on <br />' drawing C-96-083, "Project Lower", "Mine Facilities" dated March 4, <br />2003, as provided by Mr. Stover. We assume that the drawings <br />showing the location of the cross sections are available through <br />Mr. Stover's office therefore these are not reproduced and included <br />in this report. <br />Our analysis was based on soil strength characteristics obtained <br />from laboratory triaxial compression tests and direct shear <br />strength tests of samples tested obtained during our field study. <br />The soil strength values used in our analysis included: <br />Proposed natural undisturbed soil material: <br />an internal angle of friction of seventeen (17) degrees, <br />cohesion of eight-hundred (800) pounds per square foot and <br />a moist unit weight of one-hundred twenty (120) pounds <br />per cubic foot. <br />Proposed fill soil material: <br />. an internal angle of friction of seventeen (17) degrees, <br />. cohesion of four-hundred fifty (450) pounds per square foot <br />( • and <br />l a moist unit weight of one-hundred twenty (120) pounds <br />per cubic foot. <br />J Our analysis of the excavation cut slope assumed drained condi- <br />tions. Our analyses assumed that the fills would be well drained <br />and that no pore pressures would develop in the fills. <br />In our stability analyses we varied the soil strength values from <br />those listed above to assess the sensitivity of the analysis to <br />varying soil strength parameters. The variations in our analysis <br />produced relatively predictable changes to the calculated theoret- <br />ical factor of safety indicating that the stability analysis was <br />only somewhat sensitive to variances in the soil strength charac- <br />teristics. <br />Our stability analysis of the cross sections indicated a theoret- <br />ical calculated factor of safety of about 1.323 for the proposed <br />Coal Processing Facility site cut slope at an inclination of one <br />and one-half (1-1/2) to one (1) for a total cut slope height of <br />seventy (70) feet. The theoretical calculated factor of safety of <br />1.323 was based on a drained slope condition. We suggest that if <br />free subsurface water is encountered during the construction of the <br />cut slope, drains be installed to relieve the free subsurface water <br />r 1 <br />~J <br />5 <br />3ilambert ana ~,s~,oociates <br />CONSUI LNU Ok OT EIAI NIf.AI ENGINEEN5 •ND <br />MMENUI Iktl,INU <br />