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Chapter. II <br />Geo-Hydro further conducted a field inspection and obtained additional data with field <br />and laboratory testing. <br />• Recommendations were based on this work, and dealt with stability, final slopes, <br />compaction and future monitoring. <br />As noted in the report, a visual inspection of the tunnel waste disposal site confirmed <br />that the material of the disposal facility has the character of a fairly good quality rockfill, <br />and consists mostly of gravel and larger size fragments of Mancos Shale, with a very <br />limited amount of fine fraction. <br />It was also evident that the fill has been built according to the specification, i.e. the <br />material was hauled to the site with trucks and then spread in horizontal layers and <br />compacted by the transporting equipment. Central portions of the facility had a very <br />good appearance and no signs of either stability or settlement problems <br />However, some side slopes showed signs of sliding and sloughing. <br />The compaction of the rock tunnel waste was verified by a total of nine in situ tests. The <br />results are presented in the Appendix of the report. The laboratory moisture and <br />density relationship on the same material was performed and is also presented in the <br />Appendix. <br />The results of the compaction testing indicate that compaction on the order of 90% or <br />slightly less was achieved in most cases, although a low compaction of 68 to 69% was <br />found at some places where a locally increased moisture content was observed, which <br />probably corresponds to snow was mixed with the waste. <br />Geo-Hydro determined that, judging from a comparison of the results of Lincoln <br />DeVore with recent testings, the maximum densities estimated in 1979 and 1984 <br />coincided very closely, and that results of Lincoln DeVore triaxial testing, performed on <br />samples compacted to 90% of the Maximum Standard Proctor Densities, remained fully <br />applicable for the waste pile. <br />In reviewing construction practices, Geo-Hydro noted that the rock tunnel waste was <br />designed to be deposited in a facility with outer slopes of 2(H): 1(v), with two <br />intermediate berms, 10 feet wide. The maximum height of the facility was 60 feet. The <br />original design recommended to place the waste systematically in lifts. and to eliminate <br />end-dumping, with the thickness of individual lifts not to exceed 12 inches and <br />compaction by the placing equipment were recommended for the outer shell of the pile. <br />No specific construction and compaction methods were recommended for the inner <br />part of the waste pile, except that the thickness of lifts not exceed 24 inches. <br /> <br />~s <br />