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-~- <br />• ~7n tre 025ign ara'.ving .ve Jrepdred, the 5Urf3ce diLCnes nave been 025ignE0 <br />t0 r10'w tOwdr75 the southern Slde Of the prOC255ing 'ddStE OdnK 3n0 <br />discharge into surface ditch ~R-D4 and eventially to Sedimentation pona ~R- <br />P1 for treatment. Due to same variance betdeen the topography usea for <br />design and actual field conditions, a portion of surface diLCnes aroune the <br />waste bank had been directed towards the northern end of the disposal <br />area. Empire Energy 'n as constructed a sedimentation pond, northeast of Lne ~ <br />processing waste bank far treatment of water collected by the north flowing <br />ditches. We understand that Empire Energy is preparing an "as oui1L" <br />dra'ding 'dh1Ch 1nd1C3Le5 the direction Of 5Ur'fdC2 bitch f10w dn0 Cne <br />52dimenLatlOn pond. PhOtOgraOnS 1? through 14 shOW the sUri3C2 ditches <br />C7nStrUCt20 and the he'd se0lmenL3Lion 70nd. <br />We recommended that the ground surface below the 'daste disposal area be <br />compacted to at least 90 percent of standard Proctor maximum ary density <br />(ASTM D "098) prior to the placement of processing waste. In addition, we <br />recommend that the processing waste be compacted to at least 90 percent of <br />standard Proctor maximum dry density. The results of field density LeSLs <br />'de performed during our site visits are included with this letter. The <br />results of our tests indicate variable percent compaction but generally <br />indicate that the subgrade has been compacted as recommended. 'We su99est, <br />however, that the subgrade be recompacted as the disposal area expanas <br />beyond its current limits prior to placing additional processing waste. <br />From field density testing, it appears that the processing waste which has <br />been spread across the southern portion of the disposal area has generally <br />been compacted to the recommended density. It is our understanding that <br />one foot or less of processing waste has been placed. We believe that <br />compaction of additional waste can best be achieved by directing fully <br />loaded haul trucks across the top of previously placed material. [n our <br />opinion, lift thickness should be no greater than 2 feet before comp active <br />effort is applied. We suggest that initially a soils engineer be present <br />during compaction and that density tests be taken to determine the number <br />of passes of trucks necessary to achieve the recommended compaction. A <br />compaction procedure can then be developed for future compaction. Field <br />density tests should also be taken periodically during construction of the <br />waste bank to confirm that the materials are properly compacted. <br />In summary, all topsoil and organic matter has been removed from the <br />processing waste area, as required under Section 4.09.1 (4) of the MLRB <br />regulations. The subsurface drainage system has been constructed in <br />general conformance with our recommendations. Surface diversion aitches <br />have been constructed however, the recommended erosion protection has yet <br />to be fully provided. We have recommended that the constructed diversion <br />ditches be surveyed by Empire Energy to confirm that the design cross- <br />section and minimum depth and grade of the ditches has been provided. Tne <br />foundation for the processing 'daste has been compacted but we recommend <br />• that the ground surface be recompacted in advance of expanding the limits <br />., of the disposal aria. Cornoaction of the processing waste should be testea <br />by a qualified geotechnicai engineer during construction of the pile. <br />