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I . Wastewater and Stormwater Management <br />The facility wastewater and sormwater runoff from the paved containment azea will be conveyed <br />by gravity flow to a series of sormwater management structures. These management structures aze <br />shown on Drawing 1 in Appendix A and include a sediment trap, oil separator and Sormwater <br />retention pond. <br />Sediment Trap <br />The sediment trap is designed to remove sediment from facility wastewater and sormwater runoff <br />draining to the trap. The layout of the sediment trap and design details aze shown on Drawings 1 <br />and 3 in Appendix A. Wastewater will be collected and piped to the sediment trap through a trench <br />drain to be located below the loadout facility and south of the railroad track located adjacent to the <br />facility. The wastewater will be conveyed from the trench drain to the sediment trap through a <br />buried pipe. (The trench drain and pipe layout are shown on Drawing 1 in Appendix A. The trench <br />• drain will also function as part of the hydraulic oil spill containment system discussed later in this <br />report.) Stormwater runoff from the paved containment azea upgradient of the sediment trap will be <br />directed to the sediment trap through site grading. <br />During facility washdown operations, wastewater will dischazge from the sediment trap to the oil <br />sepazator through a pipe connecting these facilities. (The walls of the sediment trap have been <br />configured to direct any oil that may be floating on the water surface towazd the inlet pipe to the <br />oil sepazator.) The sediment trap is designed to contain 20 cubic yards of sediment below the <br />invert of the inlet pipe to the oil sepazator. (Sizing calculations for the sediment trap aze included <br />in Appendix C.) Approximately 20 cubic yazds of sediment is currently removed quarterly from <br />the existing sediment pond <br />During larger storm events, water entering the sediment trap will also dischazge through an <br />emergency spillway. The emergency spillway will be located along the northwest wall of the <br />r~ <br />West Elk Mine Troin Loadout Environmental Improvements Shepherd Mi!/e/, Inc <br />v~~i ~-aOT,cyon4epon.doc 3 Ju/y 1997 <br />