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LI <br /> <br /> V. GEOTECHNICAL ANALYSIS <br /> <br /> 5.01 General <br />' Specific slope stability analyses were conducted and required for mining activities performed <br /> during 2000 in the Central 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 IH:1V. <br /> Specific slope stability analyses were not conducted nor required for mining activities <br />' performed during 2000 in the North Quarry. Rather, observed conditions were compared <br /> with assumed baseline conditions used as the basis for design and consistent with the <br /> Observational Method. <br />' <br /> In Amendment No. 3, two rock mass conditions were identified for design purposes, and <br /> used as the baseline for funkier evaluations. The two baseline conditions were "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 mass. 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 2000. <br /> 5.02 Central Quarry <br />' In the Central Quarry, the alignment of the highwalls and benches of the east and west sides <br /> of Benches C and D is bearing approximately 340° to 350° azimuth. The north and south <br /> corners wrap around and tie into the east and west sides. The rock type is primarily granite <br />' gneiss and localized zones of schist with mafic and felsic intrusions (felsite dikes and <br /> pegmatites). This rock is primarily competent rock (unconfined compressive strength greater <br />' than 15,000 psi) with localized zones of poor rock. <br /> At lower elevations in the quarry, the rock mass appears to be less weathered than the rock <br />' mass encountered at higher elevations, based on observed ground conditions and behavior of <br />the exposed highwall benches. Also, this rock mass appears to be less susceptible to forming <br /> loose wedges and slabs than rock located higher in the Central Quarry. In general, the rock <br /> mass in the floor is more competent than it is higher near the original ground surface, and is <br /> less fractured with inconsistent jointing patterns. <br />The primary joint set coincides with the foliation of the rock mass. Foliation varies along <br />' Benches C and D. In general, the foliation dips out of the east side highwall in a westerly <br />direction. The primary joint set strikes parallel to sub-parallel to the mining face on the east <br />side and dips at an angle of approximately 25°to 60°. The orientation of this joint set is <br />' provided in Table I. Spacing of joints in the primary joint set typically ranges from 0.5 h to <br />' G9PROlECTSQ0200 Morrison Quarry'4p8\2000kepoT2000 geae<hnical addendum doc <br />