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20 <br /> (4)Ponds, Impoundments and Diversions <br /> The Sediment and Surface Water Control Plans are shown on Maps 13 and 14 for the <br /> East Portal and West Portal respectively. The Operator submitted these plans as a <br /> technical revision to the permit. These revisions have been necessary because of <br /> preparation plant construction; refuse area construction, and the need for more <br /> efficient routing of disturbed water as well as ease of maintenance of the overall <br /> drainage system. The area north of Ditches D 11, and D 19 to the Highway 12 <br /> easement were graded, covered with subsoil and topsoil, mulched and seeded during <br /> August and September of 1990. <br /> Management of the sediment ponds at the New Elk Mine include the pumping of <br /> water between ponds, and NECC will perform these operation while accounting for <br /> the need to allow design capacities in each pond. <br /> The Operator has three sediment ponds,which collect surface disturbance runoff <br /> from the East Portal area. These ponds are 004, 007 and 008. A fourth pond,pond <br /> 005, was reclaimed in 2003, as the area serviced by this pond was never used for <br /> mining related activities. These sedimentation ponds and associated diversion ditches <br /> have been designed according to Section 4.05.6 of the DRMS Regulations. In <br /> addition, the diversion structures have been designed utilizing the requirements of <br /> 4.05.3 and 4.05.4. Typical sections of the emergency spillways and embankments of <br /> each sediment control structure are shown in Figure 3, Typical Embankment Cross <br /> Section. Typical diversion sections are provided on Map 13 Sediment and Surface <br /> Water Control Plan-East Portal. Table 20, Ditch Data, is a summary of the diversion <br /> (ditch)data relating to Map 13. Table 21, Culvert Sizing and Figure 23, Culvert <br /> Sizing Nomograph, provide backup for culvert sizing as per requested drainage <br /> modifications. Table 23, Sediment Pond Dimensions, is a summary of sediment pond <br /> dimensions. <br /> The Operator will control West Portal drainage using ditches, containment areas and <br /> bypass culverts.All structures are shown on Map 14, Sediment and Surface Water <br /> Control Plan-West Portal. Calculations are found in Exhibit 19, Sediment Design <br /> Specifications. <br /> Runoff from the DWDA#3 is routed through a series of diversion ditches and will be <br /> routed to Containment Area No. 2. The sedimentation control plan for the DWDA#3 <br /> is contained in Exhibit 19(22)and was evaluated based on the 100-year, 24-hour <br /> event. Runoff from the undisturbed upland areas to the west are diverted around the <br /> pile in ditch D49. Runoff from a small-undisturbed upland area east of the pile is <br /> routed through the diversion ditches and routed to containment area 2. <br /> Section 2.05 RN-7 7/16/2019 <br />