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Placement and Compaction <br />The coal mine waste material will be hauled by truck to the refuse disposal area <br />where it will be spread in maximum lifts of 24 inches and compacted. The top of <br />the pile will be sloped to the east and west to ensure run -off from the fill surface <br />flows to the collection ditches and is not allowed to flow over the outslope of the <br />fill. A berm will be maintained to assure water does not flow over the outslope. <br />Coal mine waste will be placed and compacted to 90 percent of the maximum <br />dry density to prevent spontaneous combustion and to provide the strength <br />required for stability of the refuse pile. Dry densities will be determined in <br />accordance with AASHTO T99 -74. The placing and spreading of the coal mine <br />waste will be started at the lowest point of the foundation. The coal mine waste <br />will be keyed into the natural ground. Materials will be spread in approximately <br />horizontal lifts no more than 24- inches thick, and such lifts made uniformly over <br />long stretches. Each lift will be moistened or dried to a uniform moisture content <br />suitable for maximum compaction. Compaction will be carried to the edge of the <br />fills so that the final slopes are firm. The fill will be shaped and benches <br />(terraces) constructed as shown on Figure 1 and in accordance with the design <br />parameters listed above. <br />Compaction tests will be taken at a frequency and location of not less than one <br />per every other layer, at random locations across the pile. On average, when <br />coal mine waste is being placed, compaction testing occurs weekly. Test <br />locations and results will be reported to the Division in the appropriate <br />construction reports. <br />Coal mine waste materials from activities located outside of the permit area, <br />such as those activities at other mines or abandoned waste piles, will not be <br />placed in the coal mine waste bank unless approved by the Division. <br />In accordance with Buckhorn Geotech recommendations regarding taking the <br />5:1 gob slopes to 3:1 slopes, all subsoil and topsoil was removed and stockpiled <br />for later use. <br />Placement of additional coal waste shall commence from the bottom and <br />proceed up the slope. Additional coal waste must be keyed or benched into the <br />TR -76 - 12 - 11/12 <br />