Laserfiche WebLink
dams per ] 00 foot segment of ditch, 5% slope - 5 dams per 100 foot segment of ditch, and 8% slope - 8 dams per <br />100 foot segment of ditch. <br />l_J <br />Temporary diversion ditches designed to convey the 100-year 24-hour storm runoff will be cut in approximately 50 •~ <br />feet upslope from the working area of the waste pile as pile construction progresses. The temporary ditches will be <br />established in areas stripped of topsoil and are intended to divert surface runoff away from the exposed coal waste <br />materials during construction of the pile. TCC estimates a maximum of six temporary ditches will be established <br />throughout the life of the pile. <br />Waste Pile Modification <br />The refuse pile construction sequence is planned for modification as shown in Exhibit 26A-I. The modification of <br />the construction sequence, as presented in Exhibit 26A-I, will result in a stable refuse pile configuration in <br />accordance with the requirement of the DMG regulations. The bench ditch design is presented in exhibit 8M. It <br />should be noted the bench design is adequate to pass run-off from the 100 year, 24 hour event. ~ ' <br />All of the p___ rovis -ions provided in Exhibit_26 will continue to_be_followed by TCC, except as modified by Exhibit <br />26A-1. The modification presented in Exhibit 26A-] can be summarized as follows: ]j Segmented Construction - <br />Yhe requirement to place and compact the ~ m 24 i swill be followed, with testing of every other lift to verify <br />compaction requirements are met. The entire footprint of the pile can be used for stockpiling of refuse material to <br />allow for water to drain from the refuse prior to placement and compaction. The pile will be constructed in 50' <br />benches as originally planned and drainage established off of these piles as presented in Exhibit 26A. Use of the <br />entire footprint will accommodate having to stockpile refuse material during the inclement weather periods of <br />typically mid-October to late May. As presented in Exhibit 26A-1, this sequencing will not impact the stability of <br />the pile; 2) Vertical Construction -this segment has been clarified to remove the requirement to construct "A" and <br />"B" segments as proposed in Exhibit 26A. The recommendation presented in Exhibit 26A-1 to compact the entire ~ <br />lift as one unit without dividing it into segments will be followed. This will increase the stability of the fill by <br />removing the potential for establishing a slip plane between segment A & B. As noted in Exhibit 26A-I, the two <br />segment construction was for "zoned construction" and this is not required for smaller piles; 3) Temporary Road <br />Construction -this temporary road will be filled in with refuse material, as per the recommendation in Exhibit 26A- <br />I, when it is no longer required. The recommendation includes benching and tying in with existing refuse pile to <br />the north and south of this road.; 4) Subsurface and Surface Drainage - small drainage ditches will be constructed <br />downslope of the temporary stockpiles to minimize water running over and down finished slopes of the RDA. Also, <br />it was recommended in Exhibit 26A-1, that temporary drainage ditches be conswcted along the eastern edge of the <br />benches as they are constructed to prevent excessive surface runoff from Flowing over the finished compacted slope <br />of the RDA. The specific recommendation, for these temporary drainages are presented in Exhibit 26A-1..~ <br />During the construction of the RDA non-toxic material will be excavated from an area within the footprint of the <br />pile. This material will be used in conjunction with the existing topsoil to provide a 4' covering of non-toxic <br />material over the RDA. The excavated material will be replaced with compacted refuse material, which will serve <br />to increase the capacity of the RDA without increasing the physical dimension of it. The excavated material may <br />be temporarily stockpiled within the footprint of the RDA or placed in the existing stockpile to the south of the low <br />quality coal stockpile. <br />Once all of the low quality coal is processed, refuse may be placed in the pit. This will diminish the size of the <br />refuse stockpile in proportion to the amount of material placed in the old pi~ The material would then be covered <br />with at lease 4 feet of spoil and topsoil during final reclamation of the site. I <br />fi J,,.,l ,~~4~/ v <br />• <br />TR 98-31 2.05-93.1 AP P R 0 {! E - JAN U 5 1999 12/8/98 <br />