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Project: 03449 <br />Page 2 <br />of the pit moderately dry during the period of time that the pit is active. This <br />corresponds to a slope of just over 2:1. It has been our experience that the risk of <br />instability at that slope is low. However, due to the potential layering and lensic nature <br />of the soils at this site, we are recommending a maximum slope of the pit walls of 3:1 (3 <br />horizontal to 1 vertical). Therefore at a maximum assumed depth of mining of 20 feet, a <br />minimum setback of 60 feet from any man made structure will afford adequate <br />protection from the risk of slope instability. <br />Waterways present a somewhat increased risk of instability due to the continued <br />presence of a source of water and the fact that it is likely that the groundwater table will <br />slope upwards toward the elevation of the water surface elevation in the waterway. <br />Therefore, we recommend that there be an offset of a minimum of 50 feet from <br />waterways, where no mining takes place. From that point, the 3:1 slope discussed <br />above would be applicable. We have reviewed the layout of the proposed mining cells <br />and have noted that it appears that the mining plan has assumed an offset of 50 feet. <br />Thank you for consulting with us on this phase of the project. If you have any <br />questions concerning this report, please do not hesitate to contact us. <br />Sincerely, <br />SCOTT, COX AND ASSOCIATES, INC. <br />By <br />M. Edward la gow, PE <br />Professional ologist <br />