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• A digitizer was used to balance the cut and fill volumes of material needed Co create the <br />A swell factor of 15 <br />3 <br />ercent was utilized for the adjacent <br />bove-described to <br />o <br />ra <br />h <br /> p <br />g <br />p <br />y. <br />a . <br />p <br /> and back 2 spoils based on previous stu dies. A swell facator of 25 percent was used for <br /> the blasted highwall. The two adjacent spoils would be dozed into the open pit and the <br /> two back (furthest from the pi[) spoils would be graded into the adjacent v' s created by <br /> the spoil (see appropriate worksheets in Attachment 13-3). <br />Highwalls will be reduced and sloped towards the open pit. This would be accomplished by <br />drilling and shooting the highwall Isee Worksheets WC-9 and WA-9) and then dozing/ripping <br />the blasted material, into the open pit. See Table 13-2-3, Attachment 13-2 for a complete <br />listing of volumes to be dozed into the open pit. <br />A Caterpillar computer program called EMF was used to determine dozer production. This <br />program utilizes information given in the Caterpillar Handbook. All tables and charts <br />have been computerized to simulate production for track type equipment. See various <br />worksheets for production and costs. <br />• The premining and postmining topography maps were' compared for material movement. <br />Although a specific postmine topography map is not available for a 1994 mine closure, <br />drainage patterns will generally remain the same as the planned final topography. Due to <br />the fact that the topographic highs and lows will generally be located in the same area <br />after mining as they were prior to mining, it is not anticipated that wheel type <br />earthmovers will be needed to backfill the final pit. <br />Ramp grading estimates are included with spoil grading. It was assumed that ramps will <br />be graded at the same Cime as two spoils are pushed into the pit and, therefore, <br />additional cost is not estimated for this project. <br />Topsoil Replacement. Topsoil replacement volumes were based on the volume of material in <br />stockpiles at the end of year 1994. The estimated volume in each stockpile was based on <br />topsoil salvage depth per soil type over a particular area lacresl~ In an effort to <br />arrive at realistic stockpile volumes, topsoil densities were measured in the field. <br />According to Caterpillar, the swell factor for this type of topsoil would be around 35 <br />percent from BCY to LCY. The material density, as measured in the stockpile, was 2518 <br />. lbs/cy. Assuming this material was compacted to 90 percent of its original density, the <br />original density would have been 2518 lbs/cy divided by .90 = 2800 lbs/BCY. To arrive at <br />the LCY density, Cake 2800 lbs/BCY divided by 1.35 = 2075 lbs/LCY. Table 13-2-5 is based <br />1 3-53 Revised 12/01 /93 <br />