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GEOTECHNICAL STABILITY EXHIBIT EXHIBIT U <br />There are a number of structures within two hundred feet of the permit boundary of Tomichi Pit. <br />A minimum fifty foot buffer will be maintained from the permit boundary line to all excavations. <br />All reclaimed areas will be restored to relatively flat (5 -15 %) slopes except for the side slopes. <br />The sidelopes will be mined to the final reclaimed slopes of 3H:1 V down to a foot below water <br />level, then 2H:1 V to the pit bottom. Backfilling to build the lake shores will reduce the upper <br />slopes even more. <br />The side slopes will range from sand - silt -clay with slightly plastic fines to silty sand and gravels, <br />poorly graded sand and gravel- sand -clay. <br />Design factors <br />In order to determine the stability of this slope, the 2H:1 V lower slope will be evaluated for <br />safety factor. Based on Figure U -1, from Huang, shows typical internal angles of friction for <br />various materials. Assuming that the sand and gravel is classified as GC, clayey sand and <br />gravels, poorly graded sand and gravel — sand - clay, this material has an internal angle of <br />friction of approximately 34 degrees. <br />Tomichi Pit, December 2013 U -2 <br />