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Refuse on the active bench is spread, placed and compacted to 90 percent of its <br />maximum dry density to prevent spontaneous combustion and to provide the strength <br />required for stability of the coal mine waste pile. Dry densities are determined in <br />accordance with AASHTO T99 -74, Standard Proctor. Compaction can be performed <br />with a variety of equipment. The compaction specification may be attained by wheel - <br />rolling the coal mine waste with a front -end loader or water truck. A self - propelled soil <br />compactor may be used such as a Cat 815 or 825. Alternatively, a pull- behind sheeps- <br />foot roller may be utilized. Any equipment that can compact the coal mine waste and <br />achieve the compaction specification may be utilized. The placing and spreading of the <br />coal mine waste will be started at the lowest point of the foundation. The coal mine <br />waste 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 will be made uniform over <br />long stretches. Each lift will be moistened or dried to a uniform moisture content suitable <br />for maximum compaction. Compaction will be carried to the edge of the fills so that the <br />final slopes are firm. The pile shall be graded in a matter to avoid runoff over the face of <br />the pile and /or ponding of water. <br />Compaction tests will be taken at a frequency and location of not less than one per <br />every other layer, at random locations across the pile. Test locations and results will be <br />reported to the Division in the appropriate construction reports. <br />The coal mine waste pile area will be inspected, on a quarterly basis, for stability <br />by a qualified registered engineer or another qualified professional specialist experienced <br />in the construction of earth and rockfill embankments, under the direction of a qualified <br />professional engineer on a quarterly basis. Inspections shall include such observations <br />and tests as may be necessary to evaluate the potential hazard to human life and property, <br />to ensure that all organic material and topsoil have been removed and that proper <br />construction and maintenance are occurring in accordance with the approved plan. A <br />report will be provided to the Division by the inspecting engineer within two weeks of <br />the completed inspections. A copy of this report will be kept at the mine site. <br />TR -59 2.05 -27a Revised 08/11/11 <br />