Laserfiche WebLink
2.05.3 <br />(4) Ponds, Impoundments and Diversions <br />(a) There will be three sediment ponds constructed for the mine faalities. The ponds <br />are named sediment ponds B, C and D. Sediment pond D will also be referred to <br />as the refuse pile sediment pond. The loadout will have two sediment ponds. <br />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 during <br />the construction of the downhill conveyor and highway coal stockpile. It is <br />designed to handle the run-off from B-Gulch. Pond B will be a typical sediment <br />pond, capable of containing the run-off from a 10-year event with a spillway <br />system designed to haridle the peak flow generated by the 25-year storm event. <br />Dewatering is typically through the primary spillway. However, an outlet valve <br />which broke during March 2005 will require dewatering temporarily be performed <br />with a centrifugal pump. <br />Sediment pond C is located above (north of) the old Bowie railroad grade and is <br />designed to handle the run-off from C-Gulch. Sediment pond C also receives <br />inflow from the mine. A sediment pond is to provide adequate capacityto contain <br />or treat the run-off or inflow entering the pond as a result of a 10-year, 24-hour <br />precipitation event and any additional storage resulting from the inflow from any <br />underground mine. The calculations presented in Volume III, Exhibit 8, pages 7 <br />and 8; show Pond C has adequate capacity to contain inflow from the mine and <br />the 10-year, 24-hour precipitation event. Pond C has and emergency spillway <br />system designed to handle the peak Flow generated by the 25-year storm event. <br />Sediment pond D is the refuse pile sediment pond. It is designed to handle the <br />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 4, <br />Coal Mine Waste Bank Final Design for details of this sediment pond and upper <br />diversion ditch. <br />Sediment pond J is located south of the tracks below topsoil stockpile F. There is <br />a berm/upper diversion ditch designed to divert upland drainage away from the <br />topsoil stockpile. Pond J is a typical sediment pond, capable of containing the <br />run-0ff from a 10-year event with a spillway system designed to handle the peak <br />flow generated by the 25-year storm event. <br />MR-5 Z. 2.05 - 29 - 03105 <br />/~ P~hovEp <br />3 /ZZ~o <br />