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Materials Handling - Backfilling <br />The pit floor will receive only enough backfill to create final grading for drainage and to <br />establish a growth medium for revegetation. The pit slopes will require backfilling to achieve <br />final reclaimed slopes of at least 3H:1 V (see Exhibit F, Reclamation Plan Map). Because of the <br />pit size and possible limited overburden, it may not be possible to achieve complete side slope <br />reclamation by backfilling with available overburden material. In addition to the side slopes, <br />overburden material may also be required to cover the pit floor for drainage grading and to <br />establish a vegetation growth medium. The result is, depending upon the amount of overburden <br />material recovered and available for reclamation, side slope backfilling may need to be enhanced <br />with an initial "cut and fill" of the near vertical side slopes (see Exhibit F, Reclamation Plan <br />Map). The degree of "cut and fill" required, if any, will be determined during mining as <br />overburden material quantities and pit depths are verified. <br />Materials Handling - Grading <br />The 3H:1 V pit side slopes will be graded to transition into the relatively flat pit floor. Grading of <br />the pit floor may leave a subtle rolling topography rather than a completely flat bottom <br />depending on varying depths of the sand and gravel deposit. The variations in topography will <br />not create water catchment areas, but shall be graded to drain freely. The gentle slope of the <br />topography will control water flow and create a variety of microenvironments for vegetation <br />growth. <br />The side slopes will also not be graded smooth, but will contain a low profile ridging pattern that <br />follows the contour. Final grading that leaves this type of ridging pattern helps to capture water <br />for plant growth as well as reduce the velocity of runoff and slope erosion. On these slopes, <br />erosion may present a maintenance issue for the first year or two of revegetation if there are <br />large, drenching thunderstorms, but more normal low intensity thunderstorms should not create <br />more than minor rilling. <br />Blending of the pit into the Lone Tree Creek drainage will be important to prevent pooling of <br />water in the pit bottom and to avoid creating a steep slope at the pit edge that encourages erosion. <br />The final grading of this transition area will blend the topographic contouring from the pit floor <br />with the undisturbed topography beyond the pit edge. Some of this transition area will involve <br />lowering the high, steep embankment associated with the incised creek channel, while other <br />areas will transition into lower terraces that separate the mine excavation from the ephemeral <br />channel (see Exhibit F, Reclamation Plan Map). <br />All backfilling and grading will be done to stabilize the material and control erosion. Final <br />grading and seeding will be done as soon as possible after backfilling, grading, and topsoiling <br />have been completed. There will not be known toxic or hazardous materials in the backfill <br />material. The reclamation will not leave high walls on the property. In addition, there will be no <br />auger holes, excavations, or shafts left on the property. <br />Topsoil and Reve etg ation <br />The growth medium for revegetation will be a combination of overburden and topsoils. <br />Unfortunately, there is not a large quantity of quality topsoil available at the site. The topsoil is <br />Connell Carr Pit <br />DRIIS 112 Permit Application Adequacy Review Response <br />