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existing highwall of the 5A portals (See Map IV-9). It is <br />• approximately 150' NNW of the No. 5A main ventilation fans. <br /> Figure IV-15 shows a cross-section and plan view of the rock <br /> storage area. The pile depicted on this figure will hold 12,000 <br /> yd3, considerably more than what is planned to be excavated. <br /> The bottom and lower 6' of the walls of this key cut are exposed <br /> coa]. There is no suitable growth media in the key cut to <br /> salvage. Currently, there is a drainage ditch along the toe of <br /> the key cut. It collects run-off from part of the 5A portal <br /> area and channels in into sediment control pond 5A-P1. A 24" <br /> culvert will be placed in this ditch prior to building a rock <br /> ramp up into the key cut to maintain the function of the ditch. <br /> The culvert will be placed on 12" of lightly compacted material. <br /> Materials placed within 2' of the culvert during back filling <br />• <br /> will be free of large rocks and will be compacted to at least <br /> 85a standard AASHO density. The wall thickness of this Culver <br /> till be 0.064", which has a height of cover limit of 214', and a <br /> minimum cover limit of 12". Twelve inch plus rock will be used <br /> to make an energy dissipator at the discharge end of the <br /> culvert. See Appendix IU-4 for the culvert sizing calculations. <br /> The rock pile will be maintained at a slope not steeper than <br /> 2.5:1. The side slopes of the ramp that crosses the drainage <br /> ditch will be no steeper than 2:1. As there is no plant growth <br /> in the key cut now, and the rock voiume planned to be stored <br /> there will not bring the area to final grade (Final <br /> Reclamation), no re-topsoiling will be done at this time. <br /> Material containing coal, such as when the E Seam is <br /> (REV. 4/29/86) <br />IV-50d <br />