Laserfiche WebLink
Mr. Phillip Courtney <br /> February 15, 2023 <br /> Page 5 <br /> STABILITYANALYSES RESULTS <br /> The stability analyses assumed the mining will be per the mine plan. The plan includes dry mining in the Phases 2 and 3 <br /> as the water level in these cells will be controlled by slurry walls or dewatering. Mine slopes in the slurry wall lined cells <br /> will not exceed 0.5h:1v. Phase 1 will be wet mined, <br /> Setbacks listed in Table 1 (below) indicate the setback from the structure to the mining limits. <br /> The factor of safety shown below is the minimum factor of safety of the three conditions listed above. <br /> TABLE 1 -SLOPE STABILITY RESULTS AND SETBACKS <br /> Section Location Critical Structure Static Factor Seismic Factor of DRMS Draft FOS <br /> Structure Setback From of Safety at Safety at Structure Requirement <br /> Mine Limit(ft) Structure (0.0847g Static/Quake <br /> horizontal <br /> 1 Phase 3 Cell Excelsior 80 1.83 1.32 1.5/1.3 <br /> with slurry wall Ditch <br /> 27', 0.5h:1v <br /> 1 Phase 3 Cell Excelsior 80 2.35 1.70 1.5/1.3 <br /> Dewatered, no Ditch <br /> slurry wall (27", <br /> 0.5h:1v <br /> 2 Phase 2 Cell Overhead 150 3.03 1.75 1.5/1.3 <br /> with slurry wall Transmission <br /> 29', 0.5h:1v Line <br /> 2 Phase 2 Cell Overhead 150 3.67 2.17 1.5/1.3 <br /> Dewatered, no Transmission <br /> slurry wall (29', Line <br /> 0.5h:1v <br /> 3 Phase 1 Cell Baxter Road 75 2.87 1.85 1.5/1.3 <br /> 20', 0.5h:1v <br /> CONCLUSIONS <br /> The Excelsior Ditch, Transmission Lines, and Baxter Road are the nearest and only structures within 200-feet of the <br /> mine highwalls and are stable based on the Factors of Safety listed in the table above. All other structures in the area <br /> are located greater the 200-feet from the mine highwalls. Factors of Safety on other neighboring structures will be <br /> greater than those summarized in the Table above. <br />