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iii iiiiiiiiiiiii iii <br />Colorado FY 1997 Oversight Review <br />Engineer's Report <br />New Elk Mine <br />Permit C-SI-OIZ <br />Review Topic: Caal Mine Waste Banks <br />Field Review Date: June 10, 1997 _ <br />a <br />Review Team: Kent Gorham, Reclamation Specialist, DMG a <br />Ron Sassaman, Program Specialists, OSM s <br />Glen Golden, Civil Engineer, OSM <br />Scope of Review ~ <br />The scope of review is specified in the ofTicial oversight document, entitled 'Attachment to the <br />Oversight Agreement" (the Agreement), dated 12/18/96. On page A-7 of the Agreement, the <br />following statement is made: 'Each operation witft a coal mine waste bank has a water control, <br />construction, and reclamation design sufficient to ensure long term reclamation success." To be <br />consistent with this statement, no permit documents were evaluated for adequacy. Instead, DMG <br />(Kent Gorham) and OSM (Ron Sassaman) used the three criteria given in the Measurement <br />section of the Agreement (page A-7) to determine compliance with the permit intbrmation. My <br />involvement in the field review was to determine if the till structures were stable; and if there were <br />any conditions that mould likely lead to instability. <br />Evatuntion Methods <br />As specified in the Agreement, operator inspection reports, construction and maintenance of <br />water control structures, and waste pile construction requirements were checked by the inspectors <br />to determine permit compliance. <br /> <br />_~ <br />My evaluation was limited to visual observations, including assessing the following, when <br />applicable: flow from underdrains, seeps, soft or we[ areas, surface drainage and erosion, <br />sediment load of discharge water, cracking at the crest and along the slopes of the fill, bulging on <br />the slope or near the toe, shallow surface movement (e.g., creep and slippage), boils below the <br />fill, and settlement and depressions. <br />Fill Structures Evaluated <br />Two fill structures were evaluated. One is the Development Waste Pile (DWP) tf~al is located <br />south of Highway 12, and immediately west of the road that runs from the mine entrance to the <br />mine office. The other fill structure, the Refuse Disposal Area (RDA), is located north of <br />Highway 12 and directly north ofthe coal processing plant. <br />S /I ~:90I8Z•ER6 -[u c n rwcc-nr~ ~c_o~_, ~~ .,-,o_ ~ <br />