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<br />United Compnaies, Inc. ate. <br />February 15, 1994 ~p <br />page 4 ~~~ <br />The only man-made structures that are known to exist within the 20~-r_o„~ <br />feet distance is an old residence and out buildings which will be b~'_ <br />demolished and disposed of and an electrical line that feeds the <br />existing pit operation. The electrical line is an overhead line <br />that extends up the east side of the proposed gravel pit extension <br />property. <br />The mining operation consists of a relatively shallow excavation to <br />remove the gravel layer above the bedrock material. The drill logs <br />indicate the shale bedrock to be at a depth of 25 to 26 feet along <br />the east side. The excavation will be continuously dewatered <br />throughout the entire time the gravel pit is in operation; <br />preventing a fluctuating water table at or immediately adjacent to <br />the area. <br />The angle of repose is the angle from a horizontal plane that a <br />dry, loose cohesionless granular soil is stable. For the existing <br />granular material the angle of repose is on the order of 32 to 36 <br />degrees. The angle of repose can be considered equal to the angle <br />of internal friction when the soils are in a very loose condition. <br />However, the angle of internal friction increases with increased <br />density and cohesion. The existing pit run material is medium <br />dense to dense. Thus, an internal friction angle on the order of <br />40 to 44 degrees is reasonable for the pit run material. For a <br />purely cohesionless material the slope stability equation reduces <br />to: <br />S.F.= tan 0 <br />tan it <br />Where 0 = internal friction angle <br />i~ = angle of repose <br />Using the above formula for the pit run material at a slope angle <br />equal to the angle of repose produces a safely factor ranging <br />from 1.15 to 1.54 with the range of angles presented. <br />