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V. GEOTECHNICAL ANALYSIS <br /> 5.01 General <br /> Specific slope stability analyses were conducted and required for mining activities performed <br />' during 2001 in the North Quarry. Observed conditions were compared with conditions <br /> identified in Technical Revision No. 3, which allowed for modification of the slope to steeper <br />' than 1H:1V. <br /> Specific slope stability analyses were not conducted nor required for mining activities <br />' performed during 2001 in the Central Quarry. Rather, observed general conditions were <br />compared with conditions observed previously <br /> . <br /> In Amendment No. 3, two rock mass conditions were identified for design purposes, and <br />° <br /> used as the baseline for further evaluations. The two baseline conditions were <br />competent <br /> rock", representing the majority of expected conditions, and "poor rock" representing <br /> localized areas of shearing, weathering or adverse jointing. Note that the term rock mass <br />' incorporates the parent rock material plus jointing and other characteristics that influence <br /> behavior of the tnass. Typical in-situ rock mass characteristics and the corresponding <br /> strength envelopes and calculated safety factors For each of these baseline conditions were <br />' presented in Amendment No. 3, Section 4-04. <br /> The general ground conditions observed relative to the baseline conditions for each of the <br />' areas worked are described in the following sections along with a summary of the geologic <br /> mapping performed on the new final highwalls established in 2001. <br />' 5.02 Central Quarry <br />A, East Side <br />The overall slope appears stable. There are localized areas of instability on individual <br />benches. These typically occur where the pritnary joint set strikes parallel with the slope and <br />' daylights out of the highwalls, and where secondary joint sets} occur and serve as <br />detachment planes. Localized wedge and slab slip surfaces were observed on [he outside <br />edges of individual benches. These slip surfaces are infrequent and are relatively small, <br />' generally less than 10 feet in length. These features are as expected for the highwall and only <br />cause localized operational inconveniences. <br />' Twenty-six surface survey points (numbered 2001 through 2026) were established to monitor <br />the effectiveness of the repair of the unstable slope on Benches 6 and 7. Positions of the <br />surface survey points provide data to assess the performance of the slide repair during 1998. <br />' Several survey points have been damaged by mining activities. All the remaining points <br />exhibited less than 0.01 ft of displacement on average from August 2000 to April 2002, <br />indicating stable slope conditions. Survey information is provided in Appendix A. <br />' B. South End, North End, and West Side <br />' The overall slope in the south end appears stable. There are localized areas of instability on <br />individual benches due to "poor" rock mass conditions. Localized areas of instability were <br />G.IPROJfC7S?OZW Mornson QuarrylWeL'WnReporn2001 geo~echni<al addcndum.doc <br />01'1 Y~ <br />