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The man-made fills are anticipated to he <br />• constructed of re-compacted colluvial soils and coarser grained <br /> alluvial deposits which are encountered in the construction area <br /> and in the new waste area. The colluvial soils are a mititure of <br /> rock fragments, gravels and sands with a c1a}~ey silt matrix. <br /> These soils are erratic in both texture and density. The alluvi- <br /> al soils are coarse grained gravels and cobbles, with a very <br /> silty and occasionally clayey matrix. Some deposits of the~:u <br /> soils may be sufficiently "clean" that use as a free draining <br /> fill or drainage layer could be anticipated. <br /> The Bowie Member is the hardest to model <br /> for slope stability calculations. This rock member contains <br /> strata of sandstone, siltstone, mudstone and shale. In addition, <br /> it is anticipated that thin coal beds ma}• be encountered. This <br /> formation is fractured and has undergone variable amounts of <br /> chemical and mechanical weathering. Small isolated failures <br /> within the Bowie Member are anticipated but, larger, to include <br /> global, failures are not anticipated in the area of the proposed <br /> haul roads. The stability study has only considered larger, <br /> global type failure, in the Bowie Member. <br /> The existing slopes on this site vary <br /> according to the presence or absence of colluvium and the thick- <br /> ness of the colluvium. In general, slope angles which are con- <br /> trolled by the colluvium deposits tend to be 2:1 IH:I'1 and the <br /> slopes controlled by the Aowie Formation tend to range from 1:1 <br /> t.o 1.5:1 (H:V). When significant amounts of sandstone and <br /> siltstone are encountered, the slopes are much steeper, approach- <br /> ing near vertical for short distances. Based upon our analysis, <br />7 <br />