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s~ A smal drttxt should be cut from the toe of the coal mine waste bank to d'ucharge to the west <br />~ of the sediment pond, as shown in the Drawings. Cut eta 2 percent grade, this ditch wip <br />• divert rtrltoff from the western side of the sediment pond. Side slopes for this dhch should <br />be 1:1, with a 1 foot depth. Flow rates should be very small in this ditch, so riprap for scour <br />prevention i9 not required. <br />Filter material requ'ved for the nnoff control dkches can bs replaced by a non-woven geofabric <br />where ditch grades aro 10 ptrreerrt or less. Geofabrie is not recommended for side ditches on <br />steep grades. The geofabrie should bs durable and puncture resistant for placing large <br />diameter riprap. R is suggested that the minimum weight be 12 to 14 ounce per square yard, <br />with an apparent opening size lAOSI no larger than 0.1 mil6metsr to provide proper filter <br />properties. <br />4.1.8 Metsrid Balena <br />A material balance was perforated to calculate the quantities of topsoil and cover material that <br />will be required at the site to place four feet of cover for reclamation as required by Rule <br />4.10.4(5). An existing coal mine waste bank still in use at the sits wit be phased out and <br />reclaimed as part of its closuro. Ths excess cut volumes obtained from the construction of <br />• the haul roads for the proposed coal mine waste bank will be taken directly to the existing <br />waste bank for cover fill. This volume amounts to approximately 7.341 cubic yards (cyl. <br />Material used as cover fill for the proposed waste bank will be obtained from excavations of <br />undisturbed soil directly above the advancing. Through the borehole investigation, rt was <br />determined that enough unconsolidated material is available near the ground surface for the <br />excavation. As the proposed coal mine waste bank is constructed, aher every ten foot lih of <br />coal mine waste is placed, approximately 4 feet of unconsoidated material on the ground <br />surface wiY then be excavated at the back of the crest where the topsoi had been removed. <br />The heiatt of the excavation wil be approximately 10 feet, and will probably be the length of <br />the aeathtattral ground comact. As the material is being excavated, it will be placed directly <br />on the exposed 10 feet of freshly placed coal mine waste. The topsotl above the excavated <br />cover fill will be placed on a lower covered 10-foot lift on the side slops to complete <br />reclamation. Thereby, the proposed waste bank will bs eontemporartsously reclaimed in 10- <br />foot increments. Addidonal cover and topsoi that tnii bs roquired to complete the reclamatan <br />of the nest and haul roads will bs obtained from the initial excavations in the draw (storod in <br />.~ <br />9e266/1~24.pPT Coal Mine Weete sank Design fa tM 9en0arn Creek Mir <br />October 199e WE9TEC, Inc. 12 <br />