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• The fill area will be properly prepared and constructed as detailed in Agapito Associates, /nc.'s "Horse <br />Gulch Fill Stability Analysis." This geotechnical investigation report can be found in Appendix T, and is <br />dated May 2009. <br />The fill is constructed via dragline spoil from the K Ridge Pit, and T/E spoil. The dragline portion will be <br />constructed first through normal dragline spoiling. The T/E portion of the fill will be constructed in lifts from <br />the floor of Horse Gulch. Lifts will not exceed 100 vertical feet, and will typically be 25 to 50 vertical feet. <br />In general, these lifts will be placed from the outside toward the center. A suitable berm will be <br />constructed at dump points, allowing end dumps to back up to the edge of the fill, and dump. As <br />conditions require, and more likely with increased lift height, trucks may dump short of the berm, and use <br />of a dozer to push the material to the lift edge will be required. <br />The West face of the fill will have an overall slope not to exceed 3H:1V. A 30 foot horizontal bench will be <br />constructed every 100 vertical feet This will promote drainage of runoff at velocities low enough to <br />prevent cutting the face of the fill. Additionally, this will reduce the overall slope of the face to less than <br />3HA V. The final bench will be constructed at the 7570' level, and slopes at this point will reduce to 4H:1 V, <br />or less. Lifts will be placed to a maximum elevation of about 7740' and will tie into the existing ridgeline. <br />The profile of this head of hollow fill will slope downward from this point, and will remain lower than the <br />• existing ridgeline. <br />Drainage is an important consideration in the design of this head of hollow fill. An underdrain will be <br />constructed as specified in AN's "Horse Gulch Fill Stability Analysis" (Appendix T) to promote drainage <br />from within the fill. Surface water diversions are depicted in Figure T-1, Appendix T. <br />Lifts will be constructed to promote drainage, and reduce the ability of water to stand on the surface. This <br />will reduce the amount of infiltration into the fill. Where appropriate, best available construction practices <br />i <br />will be used to prevent fine material from entering the underdrain. <br />This head of hollow fill will be left as a permanent feature because it is an excess spoil fill. As such, the fill <br />will be retopsoiled, and planted in permanent vegetation compatible with the planned post mining land use <br />of Rangeland and Wildlife Habitat <br />K Pit Buttress Area <br />Geotechnical review of the K-Pit has indicated the construction of a buttress to be necessary for safe <br />mining operations, and long-term stability of the area. The need for a buttress is a direct result of the <br />• landslide in the K/G Pit area that occurred in October of 2006. <br />3-40a Revision: P?-L <br />?oy Approved: L7124101