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The fill area was properly prepared and constructed as detailed in Agapito Associates, Inc.'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 was constructed via dragline spoil from the K Ridge Pit, and T/L spoil. The dragline portion was <br /> constructed first through normal dragline spoiling. The T/L portion of the fill was constructed in lifts from <br /> the floor of Horse Gulch. Lifts have not exceeded 100 vertical feet, and have been typically 25 to 50 <br /> vertical feet. In general, these lifts were placed from the outside toward the center. A suitable berm was <br /> constructed at dump points, allowing end dumps to back up to the edge of the fill, and dump <br /> The West face of the fill has an overall slope that does not exceed 3HA V. A 30 foot horizontal bench was <br /> constructed every 100 vertical feet. This promotes drainage of runoff at velocities low enough to prevent <br /> cutting the face of the fill. Additionally, this reduces the overall slope of the face to less than 3H:1 V. The <br /> final bench has been constructed at the 7570' level, and slopes at this point have been reduced to 4H:1 V, <br /> or less. Lifts have been placed to a maximum elevation of about 7740' and tie into the existing ridgeline. <br /> The profile of this head of hollow fill slopes downward from this point, and remains lower than the existing <br /> ridgeline. <br /> Drainage is an important consideration in the design of this head of hollow fill. An underdrain was <br /> constructed as specified in AAI'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 have been constructed to promote drainage, and reduce the ability of water to stand on the surface. <br /> This reduces the amount of infiltration into the fill. Where appropriate, best available construction <br /> practices were 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 <br /> fill was retopsoiled, and planted in permanent vegetation compatible with the planned post mining land <br /> use of Rangeland and Wildlife Habitat. <br /> MAY 21 2013 340a <br /> Approved--_ <br />