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~ rI(Qlal MORRISON-KNUDSEN COMPANY, INC. i ~~ 'o e'_esE?n``dxi-s~uss;ion~s w~th,mi,ge p~e.r~sorinel Yindicatgd~th~a~t jtho.ugh seega4e~~iWlt~. ~the.pit has been observed after a rain .through-=the oit'!~alls: seeoaae.~from~^ ' the s,poil.p.ile slopes has no.tbeen reported., No seepage from the slopes of I~~ the spoil pile was observed, and the roadside drainage ditches were dry ~11~ during the site visit. ~h.e.~efrore; forjpurposes of analy is,._]b was,assume,• '~ +t the slope is we71 drained and ho hO re'"- - ~~`~ar-; ~-t~ ~'>~f~i~ i ~ti ~k:, After analyzing several variations of slope geometry and spoil properties .*;ti,' by manual methods, two slope conditions were analyzed by computer -- one ' using the very conservative values back-calculated assuming a 40-degree slope to be in a factor of safety equal to unity condition, and the other ,~ using a reduction of the values reported by D'Appolonia. The slope models analyzed are presented on Figures 1 and 2 attached to this report. The assumed surfaces of sliding shown thereon represent the result of analyzing 100 surfaces for each model. ~tie;:~comT u:ter'ro -ram..:~se.'d-~; ~• ,Bishop ty~pe.~ana~1~y~ses'~ The prope~~,.t~i:es ;used for the s :o,i~l and. the,~res.u`l~' ~ factors. of safety are tabulated belovi,.~ ~,~ Slope Cohesion 0 ;Facxtoi^'ofa° Model sf Degrees VSafetyi d I 100 22 ~„T~ II 250 28 X2,.5 CONCLUSIONS From the discussions above, it can be seen that based on conservativ ~~ .u . F estimates of the soil properties, `rs our opi-pion`that tfi~e`T=; Fae~tor~~,o, 1 ;s~a~f'e~ty for the static condition exceeds the. re uired;l11.5.. It is likel ~1 ((~~ t at some of the slopes in the active dump area are only marginally stable.jln~d-rl ~lio}Yew:er, we understand that stee ;slopes, particularly those~ins~peet` ( ; a'dj,acent to the southern haul road are to be re ra 9 stabl §?'` !, ~ tionlduring reclamation. -5-