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available in the stockpile, the material is backfilled and compacted into the previously mined <br /> areas. A similar process occurs when receiving backfill material from off-site. <br /> All backfilling and grading will be done to stabilize the reclamation material and control <br /> post-grading erosion. Final grading and stabilizing will be done as soon as possible after <br /> backfilling, compacting, and rough grading. If the area is to be stabilized with a cover-crop grass <br /> mixture, topsoil will be added prior to final grading and seeding. There will not be known toxic <br /> or hazardous materials in the backfill material. All backfill shall be composed of clean, inert <br /> material and the reclamation will not leave high walls on the property. In addition, no auger <br /> holes or shafts will be left on the property. <br /> Materials Handling - Grading <br /> Once backfill is placed to the approximate reclamation plan final grade, the area will be rough <br /> graded to establish final elevations, slopes, and transitions. Final grading may include addition <br /> of topsoil and surface preparation for revegetation. Special attention shall be given to transitions <br /> from reclaimed areas to undisturbed land. The final reclamation grading will effectively <br /> accommodate future street, utility, and stormwater drainage during land development. <br /> Reclamation grading will not create new surface drainage conveyances directed onto adjacent <br /> properties but will reconnect to historic drainage patterns and conveyances. The gentle slope of <br /> the reclaimed topography will control water flow to minimize erosion. <br /> The below-grade reservoir side slopes will include some of the steepest reclaimed grades on the <br /> site, potentially as steep as 3H:1 V. Following appropriate liner backfill and compaction, the side <br /> slopes will not be graded smooth, but will contain a low profile ridging pattern that follows the <br /> contour. Final grading that leaves this type of ridging pattern helps to reduce the velocity of <br /> runoff and slope erosion. <br /> Materials Handling—Lined Pond Construction <br /> Where the below-grade lined reservoir is to be created, the mine pit floor will be excavated into <br /> the shale bedrock. The relatively impermeable bedrock will make up the bottom of the sealed <br /> reservoir and include the reservoir liner keyway. Excavated shale bedrock will be mixed with <br /> overburden materials and used as the liner material to sperate the water storage reservoir from <br /> the surrounding alluvial aquifer. The foundation of the existing landscape/floodway diversion <br /> berms on the west and south sides of the mine pit area was previously constructed with <br /> engineered and placed liner embankment. The remainder of the constructed liner will be part of <br /> the reservoir embankment, keyed into the bedrock material, and extended upward through the <br /> entire height of the anticipated normal groundwater table. Design specifications and quality <br /> control procedures used during construction of the liner will ensure that the reservoir meets the <br /> State Engineer's Office (SEO) performance standards for permeability. During reclamation <br /> activities and prior to additional liner construction, material testing and final design of the liner <br /> will be performed. A typical liner section and general design specifications and construction <br /> procedure guidelines are presented on the Reclamation Plan Map, Exhibit F. <br /> All of the lined reservoir side slopes will be constructed at 3H:1 V slope or flatter. Reclamation <br /> of the side slopes will be concurrent with other backfilling and reclamation activities, so clayey <br /> Timnath Connell Pit <br /> DRMS 112 Permit Amendment Application Page 12 <br />