2010-12-27_PERMIT FILE - C1981012

Home Browse Search

a Iiuddtrston -Berry 1 * r fan .y s ycu y , uc Seu Disposal Packa eg� Plant Boring BH -17 encountered 2.5 feet of sand, gravel, clay, shale, and coal fill above brown, dry to moist, medium stiff sandy lean clay to a depth of 8.0 feet. Below the clay, brown, moist to wet, medium dense to very dense sandy gravel extended to the bottom of the boring. Groundwater was encountered in BH -17 at a depth of 9.5 feet at the time of the investigation. Hoist Building Boring BH -18R encountered 10.5 feet of sand, gravel, clay, and coal fill above brown, moist to wet, soft to stiff sandy lean clay to a depth of 22.0 feet. Below the clay, brown, wet, dense to very dense sandy gravel extended to the bottom of the boring. Groundwater was encountered in BH -18R at a depth of 15.5 feet at the time of the investigation. Jansen Yard Retaining ll�all Boring Jansen BH -1 encountered 8.5 feet of clay with abundant shale fragments fill above brown, dry, loose silty sand to a depth of 14.5 feet. Below the sand, brown, dry to moist, medium dense to dense sandy gravel with silty sand layers extended to the bottom of the boring. Groundwater was not encountered in Jansen BH -1 at the time of the investigation. 3.0 LABORATORY TESTING Selected soil samples collected from the borings, from the Highway 12 embankment, and from the proposed borrow source were tested in the Huddleston -Berry Engineering and Testing LLC geotechnical laboratory for natural moisture and density, grain size analysis, Atterberg limits, maximum dry density and optimum moisture (Proctor), swell/consolidation, California Bearing Ratio (CBR), and soluble sulfates content. The laboratory testing results are included in Appendix B. The laboratory testing results indicate that the native sandy clay and clayey sand soils at the New Elk Mine site are moderately plastic. The fill materials at the site were also shown to be moderately plastic. Based upon the Atterberg limits of the materials, the clays at the site are anticipated to have a slight potential for expansion. Water soluble sulfates were detected in the subsurface materials in concentrations as high as 0.003 %. The native sand soils at the Jansen Yard site were shown to be slightly plastic. These soils are generally anticipated to compress under loading; however, they may have a slight potential for collapse. Water soluble sulfates were detected in the native soils in a concentration of 0.004 %. The shaley materials that comprise the existing Highway 12 embankment were indicated to be moderately plastic. In addition, the CBR results suggest that these materials are slightly expansive when exposed to excess moisture with up to approximately 2.4% expansion measured in the laboratory. W:A2008 ALL PROIECI500456 - Ri \¢r City Conwitam W.0456.0004 Nets Elk\200 - Ge0`.0045&4)M R082410.110c 3