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Pond2 has a current capacity of 1.84 acre-feet at the invert of the combination principal <br />and emergency (trapezoidal) spillway. Area-stage information was compiled from October 1992 <br />aerial photography survey, a 1991 sediment survey and for the Rail Loop Pond only, a 1997 <br />as-built survey. Certification of these as-built drawings is limited to storage capacities <br />only and is not intended to verify design and/or construction standards. Design and <br />construction certifications were completed by the previous operator/owner and are referenced <br />above. <br />Truck Loop Pond <br />Appendix 12-1, Sediment Control and Pond Design, presents a SEDCHD 4 modeling demonstration <br />that shows the existing storage capacity (0.97 acre-feet) is adequate to detain runoff from <br />truck dump watershed azea from the 10-yeaz, 24-hour storm event and, that the as-built pond <br />configuration meets the requirements of Rules 4.05.6 and 4.05.9. <br />As part of the 2,000,000 ton per year unloading system facility modification, to satisfy air <br />emission permit requirements, HGTI will reclaim approximately 2.B acres of previously <br />disturbed area that drains to the Truck Loop Pond. Coal refuse located in the excess <br />stockpile area will be removed, and the area will be topsoiled and reseeded with seed mix Al <br />(see Tab 20, Revegetation Plan). These reclamation activities will reduce the disturbance <br />azea by approximately 57 percent and concurrently, the amount of runoff to the pond from the <br />10-year, 24-hour storm event. <br />Rail Loop Pond <br />Appendix i2-1 also contains a SEDCAD 4 modeling demonstration that shows the existing <br />configuration (1,64 acre-feet of storage) is sufficient to detain runoff from the 10-year, <br />24-hour storm event and, that the as-built pond configuration meets the requirements of <br />Rules 9.05,6 and 4.05.9. <br />As part o£ the 2,000,000 ton per year unloading system construction, to satisfy air emission <br />permit requirements, HGTI will reclaim approximately 4.7 acres o£ previously disturbed area <br />that drains to the Rail Loop Sediment Pored (see Appendix 17-1). The area wi12 be <br />backfilled, graded, topsoiled and reseeded with seed mix No. 1 (see Tab 20, Revegetation <br />Plan) . The reclamation will reduce the disturbance area by approximately 34 percent and <br />concurrently, the amount of runoff to the pond during the 10-year, 24-hour storm event. <br /> <br />TR-06 2 Revised OS/OS <br />