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Surface Facilities Area • The sedimentation control structwes associated with the portal azea, as shown on Map 24, Surface Facilities, have been constructed in accordance with previously approved permits (CYCC Permit No. 79-] 77 and TCC Pernut No. C-82-OS6). These structwes include Ponds D, E, F, G, and the associated drainage collection ditches and discharge structwes. An aerator was installed in Pond D to promote aerobic conditions throughout the yeaz. There is an existing powerline and power-box on the west side of the pond. The aerator and power supply will be removed prior to reclamation of the pond. All of the above referenced sedimentation control structwes have been addressed under Rule 2.OS.6, with the exception of surface drainage modifications associated with the new coal handling facilities. Drainage from these facilities will be channeled to Ponds D, E, F, and G as shown on Map 24, Surface Facilities. Diversion ditch and culvert designs are included in Exhibit 8, Sediment Contro] Plan. In order to provide for better drainage from the west ramp of the portal, the drainage system has been modified. The two culverts that carry water from the west ramp will be plugged, and the water will be diverted toward the Wadge sump. These culverts have been deleted from Map 24, but still exist in the field. Water will cowse to a small sediment dam which holds a 4-inch overflow pipe. Once the water reaches the top of the sediment dam, the water will enter the 4-inch overflow pipe and then drain to the sump. This system will aid in settling out some sediment from the water before it reaches the Wadge sump. From the sump, the water will be pumped up into Ditch D-2. Two water bodies, the Area 1 Pit Temporary Water Storage Basin and the Thickener Overflow Sump, utiliaed in . conjunction with ongoing mine water handling operations, have existed for years and were not previously identified or considered as "impoundments" under the regulatory definition. As a result of changes in regulatory interpretation, however, the CDMG has determined that these existing water bodies fall under the broad defmition of "impoundments" and should be identified and regulated as such. Because they aze existing water storage facilities and were not specifically designed or constructed as impoundments, the applicable requirements of Rule 4.05.9 are addressed in this context by the following descriptions and the referenced existing configuration drawings: Area 1 Pit Temnorarv Water Stora a Basin -The Area 1 Pit is a remnant surface mine pit adjacent to the Run-of- Mine Coal Stockpile), as shown on Map 24, Surface Facilities, and by Figure EX8v-1 in Exhibit 8V. ]mpoundment design, operation, maintenance, and reclamation information is provided in Exhibit 8v. The remnant pit area is a totally incised excavation, enclosed by undistwbed natwal ground and backfilled surface mine spoils, with an estimated maximum water storage capacity of approximately 200 acre-feet. The pit azea is used for temporary storage of excess mine water, as part of the closed-loop mine dewatering and recycle system. Water inputs to the pit are limited to excess dewatering flows from the mine dewatering systems and minor incident precipitation. An upgradient diversion ditch (Ditch D-3) intercepts any surface runoff from upgradient reclaimed surface mine areas and routes it around the Area 1 Pit to Pond D. While a small culvert outlet at the low point on the crest of the pit allows for minor discharge flow to Pond D if the water reaches this level, the temporary storage basin is normally managed to keep water levels well below the discharge pipe. A fixed pumping station is used to control water level, with dischazge to a de-sander, located at an old well site and then to the Coal Preparation Plant or the mine water recycling system, or directly to Pond D for dischazge to Foidel Creek. Management of the Area 1 Pit storage basin involves regular inspection and maintenance of water levels and pumping systems, and reduction of water levels prior to spring discharge to provide additional water storage capacity for any minor increases in subsequent spoil spring dischazge. . Thickener Overflow Sumn -The Thickener Overflow Sump, located adjacent to the Thickener Tank in the Coal Prepazation Plant azea, as shown on Map 24, Surface Facilities, and by Figure EX8w-1 in Exhibit 8w was excavated during Prepazation Plant construction to serve as a catch basin for the contents of the thickener, if TR OS-47 2.OS-79 Revised -March 2005