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The Slope Stability Drawing Sheet in this section shows a typical case cross section where the <br />planned excavation, permit boundary, water level and other featwes aze shown. This sheet also <br />shows the failwe line which would occw assuming that a failwe occurred at the permit boundary <br />and the material from the upper part of the slope was deposited on the lower part. This results in a <br />failwe angle of 17 degrees. <br />A permanent slope safety factor of 1.3 is desired to prevent damage to any surrounding structures. <br />The Safety factor = t went of internal angle of friction <br />tangent of the actual angle of material <br />Safety factor =tan 37 deg /tan 17 deg = .7536/.3057 = 2.46 <br />In order to produce a failwe to damage a structwe, a failwe angle of over 37 degrees would have <br />to occw, which is impossible, given the 35 feet horizontal buffer distance on the outside of the <br />excavation to the permit boundary. <br />Based on the above analysis, the slopes presented in the design of this plan, combined with the <br />setbacks outlined, will be easily stable and very conservatively meet the desired slope safety factor <br />of l .3.1, Greg Lewicki, P.E., with over 20 years of experience in mine slope safety analysis in <br />Colorado, state that this is true. <br />~,p0 REGI <br />.r ~~De <br />• ~ l~E~ ~C~G'rii~'G' <br />~ 20336 r J~~`"'!!``// <br />t~. //, 7 <br />49'•. .~ c.~i/0 9/ <br />~~~bNA Env <br />North R-34 Pit 1/07 <br />54 <br />