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0 <br />slide, fadoro we believe caused the slide and repair recommendetlone. Based upon <br />our experience at the aRe and the results of previous investlgatlons, we believe our <br />ropalr recommendations are ^ practical solution. We also believe additional <br />Irnreatigatlon, laboratory testing end analysis would rosutt in similar <br />recommendations. <br />t3aaed upon recant dleeuaelons wRh the Dhrlslon of Minerals and Qeology <br />(DMG) we rocommend the foltowing Inspection, monttoring and performance crtterla <br />for repair of the slide Brea: <br />During excavation of the elide mass and preparation of the base of the <br />repair (benching Into the cleyatane or removal of the claystone area), <br />ws should observe the excavation and seepsge arse to confirm <br />condftlons are as anticipated In our analysis and recommend <br />modifications to procedures, ss appropriate. <br />2. MonRoring of the slide area can consist of Inatalling a aeries of posts <br />along the south side of the access road. If the posts are Installed on <br />• straight line, sighting down the posts will allow movement to ba <br />detected If h occurs, and the Tins of stakes wilt provide ^ baseline for <br />measurements. Wa recommend monitoring be performed as part of <br />the quarterly Inapectlons of the sedimentation pond. <br />0. Some aattlvment of the reconstructed area should be arttlclpated. A <br />single performance crftarlon la dlttlcult to specify. We recommend an <br />initial raqulrement of morn than S feet of lateral movement rs a <br />dsflnRlon of excessive movement. The monttoring will provide <br />Indloations ae to the rate or continuation of movement, If k occurs, <br />which should also be conaldercd when detarmining tf addRlonal repairs <br />or modiflcatlona ere required. <br />Seeoaga Areas <br />Several seeps havs developed between the slide and the excess spoil fill, <br />approximate locations are shown on Fig. 1. This area wee previously strlppad to <br />bedrock and covered with 18-Inches of topaoll. Our obsetvatlone of the slumps <br />which havs developed at the seeps Indicate the slumps ar. shallow and consist of <br />downslopa sloughing of the saturated topaoll. At this time we do not believe <br />algnlflcant bedrock movement has occurred. <br />COLOWYO COAL COMPANY L P. <br />OM coot y <br />c x!aeasazaanc .NOSdWOHl/l10 : WdL5:i; 58-9 -L NOSdWOHl/l10:A9 1N3S <br />