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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 discharge 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 discharged 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 area 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 discharges from the <br />trench drain. <br />The trench drain details are 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 discharges from the trench drain to the sediment trap. <br />The shear 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 shear gate will be <br />closed to collect any hydraulic oil spills. The trench dram has been sizea tor a storage capacity <br />. in excess of-500 gallons. Hydraulic oil is stored inside the loadout facility in two 100-gallon tanks <br />and one 200-gallon tank. <br />f <br />West Elk Mine Train Loadout Environmental Improvements Shepherd Miller, mr- <br />pA11.40Treportkeport.doc 6 July 1997 (Revised April 1998)