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In the vicinity of cross section B where immediately above <br />the existing portal area weathered bedrock material is exposed, <br />the existing slopes and all proposed modifications were found to <br />1 <br /> <br />be stable. <br />CONCLUSIONS AND RECOMMENDATIONS: <br />Portal Areas: <br />With the exception of the slope above the main entry portal <br />area and the vicinity of Section A, all sites have an existing <br />condition of marginal stability (indicated factors of safety <br />between approximately 1.1 and 1.3). The main entry portal area <br />is stable due to the window of exposed bedrock present in that <br />area. As indicated in the earlier section, "Field Investigation", <br />detailed joint studies were performed on intact in-place bedrock <br />deep underground in the fan portal and were correlated with <br />detailed measurements made on the sandstone outcrop exposed at <br />the surface immediately above the existing entry portal area. <br />Good correlation was observed in joint measurements between <br />observations made in the intact bedrock underground and those <br />measurements taken at the surface bedrock outcrop above the main <br />entry portal. Copies of polar equal area stereonet plots of this <br />data are provided in the Appendix of this report. Based on the <br />results of these investigations, we would consider the exposed <br />sandstone bedrock above the entry portal to be intact and stable, <br />and not transported to its present position by any mass wasting <br />process or other form of instability. <br />Section A appears to remain unstable, based on the results <br />of analysis of the mathematical model, even with the most <br />11 <br />