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<br />• The vertical interval .between benches can also be varied, if desired. Bench <br />intervals as high as 100 feet may be possible. To increase the bench interval the effects <br />of erosion will be a primary concern. Interbench slope angles may need to be flattened <br />to maintain the average slope face near 3:1 (H:V) overall. Recommendations for sloping <br />of,benches are shown on Fig. 4. <br />For "smaller" excess spoil fills in the contour mining area, average 3:1 (H:V) <br />slopes are planned. Benches are not required for stability purposes. Erosion <br />control/constructability considerations will determine whether benches are desired. The <br />tops of these fills should be sloped to avoid surface water flow onto the fill and allow for <br />future settlement. A crown slope of 4 to 5 percent minimum is recommended to <br />accommodate these concerns. <br />Site Preparation <br />Stripping of topsoil and organic material within the fill area is required by <br />regulations and is recommended. Benching of the ground surface is not anticipated to <br />be required for the "major' fills (No. 4 through 9). However, it would be more favorable <br />from a stability standpoint to perform stripping operations parallel to the fill outslope. <br />Where slopes are steeper than 5:1 (H:V) in "smaller' fill areas in contour mine areas, <br />then benching is recommended. Atypical benching detail is shown on Fig. 8. <br />Excavation will be used to create capacity at several pond locations. Cuts of 5 <br />to 15 feet are anticipated. We recommend maximum cut slopes of 2:1(H:V) in <br />overburden soils and 1:1 in bedrock. <br />The fills will be constructed with spoil trucked or dozed to the fill surface. The <br />surface mining should cut off surtace water drainage from above the fill areas. Some <br />surface water will flow to the fill area from the limited area remaining. Movement of fill <br />from above will limit the locations where temporary diversion, ditches for surface water <br />• LORENCITO COAL COMPANY, LLC <br />LORENCITO SURFACE MINE -PHASE 1 <br />CTL/T 32, 671 13 <br />