Laserfiche WebLink
Storm runoff from all disturbed areas (except some topsoil stockpiles), pit pumpage, <br />water treatment facilities, and spoil springs will pass through a sediment pond <br />designed to ensure that all discharges meet effluent limits in Seneca Coal Company's <br />NPDES permit for the Seneca II -W Mine. A storm water permit and spill <br />prevention containment and control plan associated with the NPDES permit also <br />dictate preventative and mitigative measures for ensuring that all water leaving the <br />mine site meets applicable effluent limits. <br />Disturbed areas, as defined by Rule 1.04(36), are delineated on permit area map <br />Exhibit 12 -2. Disturbed areas drain into approved sedimentation ponds, with the <br />exception of certain haul road and access road segments that are located outside <br />approved sedimentation pond collection areas, as allowed by Rule 4.03, and with the <br />further exception of certain small area exemption locations as discussed in the <br />following paragraph. <br />The Division has granted a small area exemption from use of sediment ponds due to <br />the limited size of the area and due to the fact that ponds and treatment facilities are <br />not necessary for the drainage to meet the effluent limitations of Rule 4.05.2 and <br />applicable State and Federal water quality standards for receiving streams, and also <br />due to the fact that no mixing of surface drainage with a discharge from <br />underground workings will occur. The small areas to be exempted are the topsoil <br />stockpiles listed on Table 13 -8 -1 and shown on Exhibits 13 -2, and 13 -3. <br />(4.05.2(3)(b)(i)). <br />B. Diversions and Conveyance of Overland Flow <br />All major drainages that are to be disturbed by mining were to be reclaimed to <br />approximate the premining configuration and to blend with the undisturbed drainage <br />above and below the area to be reclaimed. The Division has verified compliance <br />with this requirement for all drainages reestablished within the permit boundary, as <br />discussed in the findings documents issued with the approval of SL -2 and SL -3. <br />Table 20 -2 provides the pre- and post -mine drainage channel summary. The <br />reclaimed drainages are located on Exhibit 20 -2. <br />The average postmining stream gradients were to have concave longitudinal profiles <br />which approximated the premining slopes. The premining and postmining drainage <br />areas of the reclaimed channels are similar in acreage and slope. After the <br />watershed was graded and the location of the drainage channel determined, the <br />channel was to be constructed to the required shape. Permanent channel <br />construction including riprap installation (where specified) was to be completed <br />within one year of completion of the final grading of adjacent backfill slopes, and <br />prior to topsoiling of areas adjacent to the channel. Following construction, the <br />channel was to be left untopsoiled to allow for initial stabilization and inspected for <br />Seneca II -W Findings Document 20 C -1982 -057 <br />Permit Revision No. 6 January 6, 2012 <br />