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2. Excavate the ponding area and restore or enlarge the sediment storage capacity. <br />The material excavated will be tested to determine its suitability as topsoil and utilized in reclamation, or <br />graded into the surrounding topography within the disturbance area, topsoiled, and revegetated in <br />accordance with the approved reclamation plan. <br />Site specifc conditions will determine the construction methods and equipment utilized at the time of <br />excavation. Sediment removal and water discharges will be conducted consistent with the approved mining <br />permit, the NPDES permit, and Section 4.05.6(3)(b). All sedimentation ponds will be inspected quarterly <br />under the supervision of a registered professional engineer and reported to the DMG. A professional <br />engineer will certify each sedimentation pond and impoundment annually. <br />Based on SCC's previous experience at the Seneca II-W Mine, pit dewatering will be primarily a seasonal <br />occurrence. The dewatering process will be a sporadic operation-controlled, occurrence depending on <br />various factors which may include the location of the pit inflows, the location of standing water in the pit, or <br />the location within the pit of the overburden and coal removal operations. When pit dewatering is required, <br />the anticipated dewatering rate will be in the range of one to two cubic feet per second or less. Any <br />dewatering discharges will be directed to a pond. The discharge from the pit dewatering will be controlled, as <br />necessary, wifh an adequate energy dissipator (i.e., rock riprap, geotextiles, metal or concrete energy <br />dissipator boxes, etc.) or discharged onto non-erodible bedrock material. Pit dewatering will have an <br />i~ insignificant impact on the proposed ponds. The pit dewatering will be sporadic versus continuous. The flow <br />rate of one to two cubic feet per second or less compared to the design 10-year, 24hour peak inflow rate is <br />very insignificant. In addition, all discharge from ponds will be in accordance with applicable discharge <br />permits. <br />All sedimentation ponds and impoundments will be maintained until the disturbed areas are reclaimed and <br />the vegetation success requirements of Tab 22 are met, the untreated drainage from the disturbed area <br />ceases to contribute additional suspended solids above natural conditions, and the drainage leaving the <br />pond meets applicable State and Federal water quality requirements, if any, for the receiving streams. All <br />temporary ponds will be removed when the appropriate sections of the regulations are satisfied. Permanent <br />impoundments will be reevaluated prior to bond release and remedial construction performed to satisfy the <br />appropriate sections of the regulations. Prior to submittal of a bond release request, SCC will submit a <br />complete technical revision demonstrating that each permanent impoundment meets the requirements of <br />Rule 4.05.9(13) for permanent impoundments. <br />When sedimentation ponds are removed, the affected land will be regraded and revegetated pursuant to the <br />CDMG's regulations, Section 4.05.17 and the approved Reclamation Plan. <br />Design Methodology. The precipitation runoff (peak flow and volume) is estimated using the Soil <br />Conservation Service (SCS) triangular hydrograph techniques as described in Design of Small Dams (U. S. <br />PR-05 5 Revised 01/O6 <br />