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In completing its review of the amended application, the Division converted the <br />applicant's analytical projections into an analytical format more familiar to the <br />Division. The applicant projects an average overburden swell factor (loose <br />swollen overburden volume divided by bank overburden volume) of 1.32. <br />Further, the applicant projects a bulking factor (swollen backfilled volume <br />divided by excavated pit volume) of 0.91. Considering the average mined depth <br />and extracted seam thickness, this suggests an average post-mining topographic <br />deflation of 4.6 feet. Adjusted for the possible 4.5 percent discrepancy in <br />observed versus original projected bulking discussed above, the post-mining <br />topography might rise by an additional 1.8 feet, resulting in an average <br />post-mining topographic deflation of 2.8 feet. In either case, the projected <br />post-mining topographic configuration is considered by the Division to constitute <br />an acceptable approximate original contour configuration. <br />The Division has approved a reclamation plan for delay in contemporaneous <br />reclamation, as allowed under Rule 4.14.1(1)(c). The approval was granted due <br />to the nature of the operation plan which entails concurrent mitring of two <br />separate mining areas (north and south) with a single dragline. Pit development <br />in both the north and south blocks begins with an initial box cut. Development <br />proceeds from each box cut in opposite directions at different times during the <br />operations plan. The sequence of pit development will not allow for backfilling <br />and grading to be completed within 180 days of coal removal. At the point of <br />maximum disturbance, there will be two open pits within each mining block. <br />Pursuant to Rule 4.14.1(1)(c), the Division is approving a variance from the <br />requirement that rough backfilling and grading be conducted within 180 days <br />following coal removal. This variance applies to the entire permit area. L2 <br />addition, a variance from the requirement that there be no more than 4 spoil <br />ridges behind the pit currently being work is approved for a 25.5 acre area of the <br />north block and a 41.8 acre area of the south block. Within these areas, as <br />depicted on Exhibit 19-1, up to it spoil ridges will be allowed between the two <br />open pits in the north block and up to 11 spoil ridges will also be allowed <br />between the two open pits in the south block, to allow for sufficient operational <br />area to allow for highwall reduction grading. The additional spoils have been <br />accounted for in the reclamation cost estimate for the reclamation bond. <br />Potentially acid or toxic-forming spoil material has been and will be identified by <br />sampling regraded spoil, and will be chemically treated or buried with a <br />minimum of four feet of topsoil. By neutralizing and/or isolating any acid or <br />toxic-forming material from the surface, and mixing limited quantities of such <br />material with much greater volumes of alkaline and benign spoil material, any <br />negative effects of problematic material will be ameliorated. <br />The Division approves this method for covering acid and toxic forming materials <br />in order to prevent leaching into surface and ground water and to insure backflll <br />stability. (4.14.3(2)). <br />34 <br />