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• 2.05.3 <br />(4) Ponds, Impoundments and Diversions <br />(a) There will be three sediment ponds constructed for the mine facilities. The <br />ponds are named sediment ponds B, C and D. Sediment pond D will also be <br />referred to as the refuse pile sediment pond. The loadout will have two <br />sediment ponds. The ponds are named sediment ponds J and K. <br />Sediment pond A was deleted from the design. <br />Sediment pond B was relocated below (south of) old State Highway 133 <br />during the construction of the downhill conveyor and highway coal stockpile. <br />It is designed to handle the run-off from B-Gulch. Pond B will be a typical <br />sediment pond, capable of containing the run-off from a 10-year event with a <br />spillway system designed to handle the peak flow generated by the 25-year <br />storm event. Dewatering will be through the primary spillway or an optional <br />centrifugal pump. <br />Sediment pond C is located above (north of) the old Bowie railroad grade <br />• and is designed to handle the run-off from C-Gulch. Sediment pond C also <br />receives inflow from the mine. A sediment pond is to provide adequate <br />capacity to contain or treat the run-off or inflow entering the pond as a result <br />of a 10-year, 24-hour precipitation event and any additional storage resulting <br />from the inflow from any underground mine. The calculations presented in <br />Volume III, Exhibit 8, pages 7 and 8, show Pond C has adequate capacity to <br />contain inflow from the mine and the 10-year, 24-hour precipitation event. <br />Pond C has and emergency spillway system designed to handle the peak <br />flow generated by the 25-year storm event. <br />Sediment pond D is the refuse pile sediment pond. It is designed to handle <br />the run-off from the entire refuse pile area. There is an upper diversion ditch <br />designed to divert run-off away from the top of the refuse pile. See Volume <br />4, Coal Mine Waste Bank Final Design for details of this sediment pond and <br />upper diversion ditch. <br />i• <br />Sediment pond J is located south of the tracks below topsoil stockpile F. <br />There is a berm/upper diversion ditch designed to divert upland drainage <br />away from the topsoil stockpile. Pond J is a typical sediment pond, capable <br />of containing the run-off from a 10-year event with a spillway system <br />designed to handle the peak flow generated by the 25-year storm event. <br />TR-38 2.05 - 29 - 03/05 <br />