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• <br />r1 <br />LJ <br />n <br />U <br />Haul Rodd <br />Drainage and conveyance features have been included in the construc- <br />tion of the haul road to the truck dump. The locations and sizes of <br />haul road culverts are shown on Drawing D-2-3. This haul road follows <br />the route of an existing road for much of its length. New portions <br />have been constructed in the vicinity of the county road leading to <br />the mine and in the vicinity of the truck dump area. Drainage <br />features of the road construction include a drainage Swale on the <br />uphill side of the road where necessary to direct the intercepted <br />runoff to the culverts. The culvert sizes vary from 18 inches to 48 <br />inches in diameter. The design criteria for all the culverts is the <br />10-year, 24-hour precipitation event. <br />4.6.2.3.2 Sediment Control <br />Unit Train Loading Area <br />Sediment from the disturbed area of the loadout facility is controlled <br />in Pond 1, shown on Drawing D-2-4. The sediment from the entire <br />length of the railroad spur is directed to Pond 1 by the drainage <br />Swale described in the previous section. The sediment storage volume <br />of the pond is based upon the sediment production rate of 0.1 acre- <br />feet per acre of disturbed area. The total disturbed area contri- <br />buting to Pond 1 is 8.1 acres. The volume of the pond dedicated to <br />sediment storage is 0.6 acre-feet assuming a 3-year accumulation. The <br />calculations of runoff and sediment volumes, along with pond sizes, <br />are shown in Appendix 4-B. <br />Pond 1 will be lined as will be the other ponds at the facility with <br />30 mil, 3 ply, nylon reinforced Hypalon. The pond linings are <br />designed to prevent coal fines from migrating into the hydrologic <br />environment at the facility. <br />4-134 <br />