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The dewmtering borehole site will consist of a 14 inch borehole, drill pad, pump and control building, powerlines, <br />end discharge line. The control building will be approximately l0~ x l0' x l0' and be placed on a concrete pad <br />10' s 10' x .5'. The drill pad will be approximately 100' x 200' within which [tvo 10' x 10' x 50' mud pits will be <br />cxcavated. A 17 I/2 inch nominal diameter hole will be drilled into [he sump area. Upon completion of drilling, <br />the mud pits will be backfilled with [he material excavated from them. Approximately 1.350 feet of 14 inch metal <br />casing will be installed into the. boring and [he annular space grouted. A submersible pump capable of pumping <br />350 gpm will be installed in [he casing. Also, a transformer will he installed a[ the site to provide [he required <br />power for the pumps. The transformer area will have a 7' high security chain link fence placed around its <br />perimeter. A powerline, approximately I I/2 miles in length, will be constructed to tie [his location into TCC's <br />power system. To complete the well installation, an 8' length of 8' diameter corrugated metal pipe with lid will be <br />place around the borehole. The material excavated from the 8' diameter pit will be spread out over the pad. The 6 <br />inch riser pipe from the pwnp will exit the 14 inch casing and a 90 degree elbow and associated valuing will be <br />attached fa' directing the discharge pipe into the 8" HPDE line going to [he settling ponds. The pipine to the <br />ponds will he buried to minimize freezing problems and will run approximately 4,800 feet to the tren[ment ponds. <br />Power will he brought into the pumps from TCC's eeis[ing powerlines. <br />The pipe leading from the borehole to the treatment ponds will he constructed of I-IDPE. This material is <br />extremely tlesible and, due to this characteristic, it was chosen to be used a[ the facility. This flexibility is <br />exhibited in the cold bend radius of the pipe, which is 160 inches. This means the pipe can be offset 80 inches <br />vertically over a length of l60 inches. This greatly exceeds [he anticipated offset from subsiding [he line. <br />The water from the sump will be discharged into two ponds which are approximately 170' x SS' x S'. The ponds <br />will he constructed in an area approximately 300' x 250'; topsoil will he salvaged and stockpiled adjacent to [he <br />ponds. This will require salvaging approximately 5,555 CY of topsoil. The sah~aged topsoil will be stabilized <br />with the topsoil stockpile stabilization seed mis[ure. Prior to discharging into the ponds, chemicals will be added <br />~;vhich +vill aid in the settling of suspended and dissolved materials. The same chemicals used at the Fish Creek <br />Dewatering borehole will be used at this installation. TCC's experience with these chemicals shows that their <br />introduction [o the effluent is adequate to allow compliance with applicable water quality standards. An inline <br />static mixer will be used to distribute the chemicals throughout the water stream prior to discharge to the ponds. <br />Piping into the ponds will allow for selecting which pond serves as dte primary treatment pond and which serves <br />as the secondary treatnent pond. An inner pond line will allow for tlow behveen the ponds. A l S' wide road will <br />encircle the ponds to allow for future maintenance. A buried 8" discharge line will carry the discharge to Foidel <br />Creek. The line will he buried approximately 4 feet. A flow measuring device will be used [o ob[aiu the <br />appropriate tlow measurements. <br />A 10' x 15' x 30' building will house the chemical feed system and control panels for the dewatering pump. As <br />shown in Figure I, Exhibit 8C(I), an access road (loop) will be constructed into the treatment ponds. <br />Approximately 740 CY of topsoil will be salvaged from these short segments of road leading inln the ponds. The <br />topsoil will be windrowed to the side and seeded with the topsoil stockpile stabilization seed mixture. The <br />building will be constructed on a 10' x 30' x .5' concrete pad. The location is shown on Maps 17 R I8. <br />The sediment control far the site will consist of seeding and mulching the topsoil stockpiles and cut and fill slopes, <br />and use of adjacent established vegetative filter. The SAE demonstration for this area is presented in Exhibit <br />SC, EMD Dewatering Treatment Facility. The design for the treatment ponds is presented in L-xhibit 8C(I ), EMD <br />Treatment Pond Design. <br />• <br />MR 97-154 2.05-75 Revised 9/9/97 <br />