PERMFILE65376 - Laserfiche WebLink

Home Browse Search

6.4.4 EXHIBIT D-MINING PLAN Water Diversions Water diversions will include pumping groundwater from dewatering trenches into a sediment pond before discharging to the river. Pump rates are expected to be 200-300 gpm. For dewatering of Cell A, a sediment pond will be constructed in the adjacent un-mined Cell B. For dewatering Cell B, a sediment pond will be constructed in the adjacent backfilled Cell A. For dewatering Cell C, a sediment pond will be constructed in the adjacent un-mined Cell D. For dewatering Cell D, a sediment pond will be constructed in the adjacent backfilled Cell C. Sediment ponds are to be constructed by excavating 6'-8' feet deep Discharge overflow pipes will be constructed of 4" irrigation pipe and will be placed on the ground surface and routed to the river as shown in Exhibit C-2. Timetable and Size of Mining Areas The mining operation is expected to last for 3 years, however this could vary depending upon market conditions. The approximate size of areas to be worked at any one time correlates to the size of the mining Cells. Table 6.4.4-2 shows the mining Cell size and the approximate timetable for working each Cell. Table 6.4.4-2. Mining Timetable MINING CELL APPROXIMATE AREA TO BE WORKED AT ANY ONE TIME [acres] APPROXIMATE TIMETABLE CELL A 2.4 Year 1 CELL B 4.0 Year 1 CELL C 6.4 Year 2 CELL D 11.1 Year 3 Nature of the Deposit The overburden occurs at a thickness from 4-12 ft and is composed of sand silt (ML) silty sand (SM) and some sandy and silty clay (CL). Sand and Gravel occurs at a thickness of 10-15 ft. Directly beneath the sand and gravel is a weathered zone of shale occurring at a thickness of 3-6 ft under which is the un- weathered Pierre shale. Commodities The primary commodity is sand and gravel to be used for the construction industry. The are no incidental commodities. Explosives No explosives will be used for the mining operation. Gardels Pit Rev AR-1.0 Regular 112 Permit Application