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Placement and Compaction <br /> The coal mine waste material is hauled by truck to the disposal area and initially end- <br /> dumped in an area for drying. The coal mine waste is worked with dozers and track hoes <br /> to assist in the drying process, and when necessary mixed with coverfill material to <br /> expedite drying efforts. Mixing of coverfill material with refuse will be managed to ensure <br /> the minimum amount of coverfill material required to cover Gob Pile #2 and Gob Pile#4 <br /> will be reserved at all times. Appendix A in this volume presents the minimum amount of <br /> coverfill material required to cover Gob Pile#2 and #4. <br /> Trenches are cut through the end-dumped material to allow better drainage. Berms are <br /> constructed in the low areas to collect the water and to keep water from flowing over the <br /> outslopes of the pile. Temporary drain pipes are used to convey water that is collected in <br /> the low areas to existing stabilized ditches. Water is not allowed to flow over the <br /> outslopes of the pile. The pipes only function is to collect water that is draining from the <br /> coal mine waste material. The pipes are not an integral part of the surface water control <br /> system. <br /> The maximum amount of un-compacted gob in both refuse areas (Gob Pile#2 and Gob <br /> Pile#3)will not exceed 200,000 cy total. <br /> The coal mine waste is placed and compacted in the acti\e working area after it is <br /> sufficiently dried. The top of the pile is sloped to ensure nun-off from the fill surface flows <br /> to the collection ditches and is not allowed to flow over the outslope of the fill. A berm <br /> 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 dry density <br /> to prevent spontaneous combustion and to provide the strength required for stability of <br /> the refuse pile. Dry densities will be determined in accordance with AASHTO T99-74. <br /> The placing and spreading of the coal mine waste will be started at the lowest point of <br /> the foundation. The coal mine waste will be keyed into the natural ground. Materials will <br /> be spread in approximately horizontal lifts no more than 24-inches thick, and such lifts <br /> made uniformly over long stretches. Each lift will be moistened or dried to a uniform <br /> moisture content suitable for maximum compaction. Compaction will be carried to the <br /> edge of the 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 per every <br /> other layer, at random locations across the pile. On average, when coal mine waste is <br /> being placed, compaction testing occurs weekly. Test locations and results will be <br /> reported to the Division in the appropriate construction reports. <br /> MR-144 - 12- 11/15/13 <br />