2009-02-03_GENERAL DOCUMENTS - C1981041

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D. Sedimentation Ponds Information on the surface water sediment control system can be found in Volume 3, Tab 13, page 13-5 of the permit application. A list of sediment control structures, along with references to appropriate exhibits for designs and cross sections, are found in Table 13-4 of the application. Calculations used to design these structures are given in appendix 13-2 of the permit application. Sediment Pond 8 at the South Portals was reduced in size and storage capacity in association with the PR-3 reclamation plan. Location and configuration of the revised Pond 8 is depicted on Exhibit 6C-A, and design elevations and capacities are listed on page RSS-4, of Appendix 13-2. Eight sediment ponds are in place, as previously approved by the Division and have been treating disturbed-area surface water runoff under the existing permit for the Roadside Mines. All ponds have performed well over this period. These ponds are described in the Summary, "Description of Operations Plan" section of this document. References to designs for these ponds and their locations are found in Tables 13-5 and 13-6 of the permit application. All but two sediment ponds are designed to contain the runoff and sediment from a 10-year, 24- hour precipitation event. Sediment Ponds #1 and #2 were combined to contain the 25-year, 24- hour storm event. Sediment ponds #1, #2, #7, #8 and #11 require pumps as the principal dewatering mechanism because the surrounding ground elevations are higher than the sediment pond bottom elevations. The emergency spillways are designed to pass the 25-year, 24-hour peak flow. The outflow below the spillway is to be riprapped where necessary to control erosion. With the exception of approved small area exemptions, all surface runoff from disturbed areas is routed through one of eight sediment ponds (note that Ponds 1 and 2 have been combined and now form a single pond): Area of Disturbance Rail Loadout North Portal North Decline South Portal CRDA-1 CRDA-2 CBA-2 Sediment Ponds Other Structures Pond #1 and #2 Berm, short ditch Pond #13 Pond #7 Ponds #8, #9 Pond #6 Pond #10 Pond #11 Diversion, berms and ditches Berm, ditches, sumps Diversion, berms, pipes Berm, underdrain, ditches Diversion, ditches There is no Sediment Pond #3. Former Ponds 4, 5, and 12 have been reclaimed. E. Impoundments The only impoundments existing within the permit area in addition to sediment ponds are sewage lagoons, and three non-discharging sumps. Former Mine-water treatment pond 12 has been reclaimed. A set of evaporative, non-discharging sewage lagoons has been permitted near the loadout for treating water from the Roadside Mine and the loadout. Permit Revision No. 4 23 February 3, 2009