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Timm Comer <br />Mill Platform Machine Vibration Effects <br />Project 74201125G <br />September, 20, 2012 <br />AM <br />• <br />I M's <br />Figure 5: Soil Response to Dynamic Loading <br />The maximum vertical deflection for the ball and rod mill vibrations was estimated as 0.24 inches by the <br />model. The magnitude of the maximum deflection is the same for both machine vibrations because the <br />magnitude of the stresses were the same (7,000 psf). Only the frequency is different between the two <br />loads. This deflection represents elastic deflection and not permanent settlement from static foundation <br />loads which have already been addressed in the soils and foundation recommendation report. <br />Densification of the compacted structural fill from the foundation vibrations is not expected to occur as the <br />structural fill is comprised of minus 24" waste rock and minus 3" waste rock that was systematically <br />compacted using a method developed by the U.S. Army Corp of Engineers (EM1110 -2- 2301). Based on <br />review of this method specification, it is reasonable to assume the material is adequately compacted to <br />approximately 80% relative density. Deformations of the subgrade material resulting from the dynamic <br />loading of the foundations are estimated to be minor (less than 1 /4th of an inch). <br />Geomembrane Liner Response to Machine Vibration <br />Effects on the liner from the machine vibrations can be assessed by examining the vertical stresses and <br />horizontal and vertical strains at the level of the geomembrane liner. The geomembrane liner is <br />approximately 15 feet below the foundation bottom. A point 15 feet below the applied dynamic stress was <br />examined within the equivalent - linear elastic model to estimate the stress and strain levels resulting from <br />the machine vibrations. Figures 6, 7 and 8 show vertical stress, vertical strain and horizontal strain, <br />respectively, occurring at the level of the geomembrane. <br />SAprojects\1125g squaw gulch valley leach facililty designth2 - design \mill platform machine vibration letters sept 2012 \mill platform machine vibrations (3).doc <br />