Laserfiche WebLink
Chapter II <br /> Sediment ponds A, B, and C, which were built earlier, can safely pass a <br /> 10-year/24-hour event plus three years of sediment from the rock tunnel dump area. <br /> Construction of the additional ponds, D & E, is scheduled for 1988. The additional <br /> ponds are intended to increase the capacity for handling mine discharge. <br /> The total capacities of the five ponds in series will then be: <br /> Available Sediment Capacity = 8.85 ac. ft. <br /> Available Water Capacity = 9.97 ac. ft. <br /> Total Available Capacity = 18.82 ac. ft. . <br /> Required Sediment Capacity = 5.88 ac. ft. <br /> Required Water Capacity = 10.29 ac.ft <br /> App.11-B-3 contains documentation for the Adit/Rock Tunnel. The water control <br /> structures associated with the project are depicted in Ex. II-B-App.7 Att. 4-1 & 2 found <br /> in map jackets in Vol. 3. <br /> The sediment pond calculations and portal and yard area cross-sections are covered in <br /> Attachment 4 to this Appendix (II-B-App.7-Att.4) <br /> (5) Coal Refuse Facility. <br /> The facility includes a surface water diversion/collection system and two sediment <br /> ponds. Geo-Hydro Consultants developed the drainage control plan for this area. <br /> Golder & Associates did calculations for Phase II of development on the Sutey pile, and <br /> verified that the two ponds are adequately sized to meet regulatory requirements for <br /> Phases I and II. See App. II-13-5, Exh. II-B-App. 5-1 through 11 and App. II-B-7, Att. 5, <br /> for design criteria. <br /> An additional sediment pond, approved in TR-8 on August 27, 1987, will be constructed <br /> as part of the Phase III expansion of the pile. The Phase IV expansion of the pile, <br /> which has not yet been permitted, will include addition of another sediment pond. <br /> Calculations for these two additional sediment ponds are included in App.11-B-5. <br /> b. Ponds and Impoundments. <br /> Ponds and impoundments have been designed and constructed to settle suspended <br /> solids from water flowing out of disturbed areas. <br /> The ponds and impoundments have been located out of perennial streams, and where <br /> surface disturbance can be kept to a minimum. The impoundments have a capacity of <br /> less than 20 acre feet and a vertical height of less than 10 feet below the crest of the <br /> emergency spillway and the toe of the fill. <br /> 27 <br />