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24-hour storm event. Discharges from the west spillway will drain west, away from the retention <br />Pond. «n~~ <br />w~~~ <br />Periodic cleaning of the stormwater retention pond will be required to remove sediment <br />accumulations in the pond to maintain the pond design capacity. Sediment accumulation in the <br />retention pond must be removed before the sediment level reaches the bottom of the south <br />spillway dischazge pipe (approximately 9 inches above the pond floor). An access ramp at a 10% <br />grade is provided to allow a motorized loader easy access into the pond for removal of sediment. <br />During cleaning operations, water in the pond will be pumped out and hauled to one of the other <br />sediment ponds located at the mine or dischazged to the stormwater inlet. Sediment removed <br />from the pond will be placed in the lower refuse pile at the mine. <br />Hydraulic Oil Containment <br />As previously discussed, a trench drain located below the loadout facility will collect washwater <br />from facility cleaning activities. The paved azea below the loadout facility will be graded to drain <br />to the trench drain. The water collected in the trench drain will flow through a buried pipe to the <br />sediment trap. As discussed below, this trench drain will also function to contain spills of hydraulic <br />oil at the loadout facility that may occur during facility operations. This containment will be <br />accomplished by providing storage capacity in the trench drain and controlling dischazges from the <br />trench drain. <br />The trench drain details aze shown on Drawing 2 in Appendix A. (An equipment detail sheet for <br />the trench drain is included in Appendix D.) As shown on Drawing 2, the trench drain will be <br />equipped with a shear gate for controlling dischazges from the trench drain to the sediment trap. <br />The sheaz gate will be opened only during routine loadout facility washdown activities or when <br />required to drain the trench after a storm event. During all other times, the sheaz gate will be <br />closed to collect any hydraulic oil spills. The trench drain has been sized for a storage capacity <br />• <br />West Elk Mine Train Loadou! Environmental /mpravemend Shepherd Miler, Inc <br />P:w~or~n~.a« 6 July 1997 <br />