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Chapter. II <br />Geo-Hydro's inspection and testing showed that the waste had been deposited in <br />horizontal lifts, as specfied, and compacted to an acceptable degree (although recent <br />• snowfall had caused some high moisture content in the fill, which resulted in less <br />satisfactory compaction). <br />Because of the good quality of the rockfill and the extremely conservative design of the <br />pile, Geo-Hydro did not consider these local variances as critical for stability, although <br />local stability problems, such as shallow sloughs, slides and mudflows, had occured <br />because of the high moisture content. <br />Geo-Hydro recommended that while there was no apparent need to try to achieve <br />compaction at temporary slopes, the permanent slopes should be built with a slope of <br />2(H) : 1(~ and compacted. <br />b. Adit/Rock Tunnel Pad Expansion. <br />The initial Adit/Rock Tunnel portal faceup and yard area were a cut and fill program. <br />The volume of the cut matched the fill. <br />The pad area was expanded a total of 2.6 acres utilizing approximately 46,700 cu. yds. <br />rock materials excavated during construction of the Adit/Rock Tunnel for the fill.. <br />Technical Revision 6, approved Nov. 5, 1986, allowed expansion of the pad by .9 of an <br />acre. Technical Revision 7, approved Feb. 10, 1987, allowed further expansion of the <br />pad by 1.7 acres. <br />The fill was constructed using standard engineering practices and under the <br />supervision of a registered professional engineer, with lifts ranging from approximately <br />1 foot on the outslopes to 2 feet maximum in the interior. Grading and compaction was <br />done with a D-8 Caterpillar tractor. Compaction was also accomplished by routing the <br />haul trucks over previously deposited areas. <br />Before construction of the fill, vegetation was removed and topsoil excavated and <br />stored on the existing (west) tunnel topsoil pile. <br />The small drainage paralleling the toe of the existing slope was diverted south as it exits <br />from the 36" CMP that goes under the road to the tunnel wells. This drainage has a <br />very flat slope --2 to 3 percent -- and when diverted this slope was maintained. <br />c. Trash Pile. <br />Two feet of tunnel rock were placed down, and a berm built around the area, before <br />construction of the trash pile near the Adit/Rock Tunnel project, as approved by the <br />Technical Revision of Aug. 6, 1982. <br />• <br />47 <br />