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Banks and Gesso, LLC <br />the 3:1 slope will extend 13 feet vertically below existing ground) and a 2:1 slope will be <br />constructed from the 3:1 slope to bedrock. <br />Analysis and Results <br />A slope stability analysis was prepared using the soils values and geometry presented <br />above. The following situations were analyzed: <br />• the stability of the mining face <br />• the stability of the secondary face if the mining face fails before reclamation <br />• the long-term stability of the reclaimed slope <br />This analysis was simulated without pore pressure because the slurry wall will be <br />installed prior to mining and the area to be mined will be dewatered. The proposed <br />mining face is a 0.5:1 slope. As expected, the mining face indicates a factor of safety <br />(FOS) of less than 1 (figure 1). However, the slip face is within 10 feet of the mined face <br />and falls well within the proposed setback. <br />A second analysis was conducted to estimate the most likely slope failure for the mined <br />slope, should the slope fail. This analysis, also conducted without pore water pressure, <br />showed that the top of the failure surface would daylight about 10 feet back from the <br />cuttace and the bottom of the failure surface would daylight near the toe of the 0.5:1. <br />This newly created secondary face was analyzed for stability and was found to be stable <br />with a FOS of 1.4 (figure 2). Thus, if the mined face fails, it should remain well within the <br />proposed 25 foot setback, and the newly created slope should be stable while awaiting <br />reclamation. <br />The final analysis, simulated with a water table at 3 feet below existing ground, was <br />conducted to estimate the long term stability of the reclamation slope of 3:1/2:1. The <br />analysis indicated that the proposed slope will be stable with a FOS of 1.6 (figure 3). <br />Heit Sand and Gravel Mine 02044 <br />SW Meadow, LLC February 2003 <br />31 <br />