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Junuurv 15, 2008 <br />Page 40 <br /> 46 .,. <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> al, <br /> <br /> <br /> <br /> <br /> <br /> v <br />N V. c <br />Figure 32. Photograph of Surface Cracking; Associated with 2001 Highwall Failure in <br />GTest Pit Downdip of 7,Dip Pit Barrier Pillar Area <br />results indicate that the Z-Dip hillside is expected to remain stable under the assumed conditions. <br />f=igure 33 shows that only minor near-surface failure is expected as predicted by inelastic failure <br />indicators and low equilibrium velocities. Almost all ofthe localized failure shown in this figure <br />was induced by previous G-Test Pit mining. 'Tile low velocities indicate the model comes to an <br />equilibrium state and the slope is stable. The assumed high groundwater and low L-Roof <br />mudstone strength are conservative. Recent laboratory testing of Z.-Dip Pit rock samples <br />('Table 1) show significantly higher I.-Roof mudstone strengths compared to post-landslide <br />samples from G-pit. Long-tern groundwater records indicate significantly lower groundwater <br />elevations than assumed to induce instability of G-Pit, even during peak precipitation periods. <br />'The analysis indicated the slope has an estimate safety factor of over 4.0. <br />Conclusions for the Z-Dip Pit stability analysis results are summarized as follows. <br />The hillside is expected to remain stable during Z-Dip mining, even under severe <br />groundwater and low strength conditions. <br />The analyses are conservative because the extreme conditions assumed in till' model have <br />not been obserycd, <br />Agapito Associates, Inc