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<br />V. GEOTECHNICAL ANALYSIS <br />' 5.01 General <br />Specific slope stability analyses were not conducted nor required for mining activities <br />performed during 1999. Rather, observed conditions were compared with assumed baseline <br />conditions used as the basis for design and consistent with the Observational Method. <br />1 Two rock mass conditions were identified for design purposes, and used as the baseline for <br />further evaluations. The two baseline conditions were "competent rock", representing the <br />' majority of expected conditions, and "poor rock" representing localized areas of shearing, <br />weathering or adverse jointing. Note that [he term rock mass incorporates the parent rock <br />material plus jointing and other characteristics that influence behavior of the mass. Typical <br />' in-situ rock mass characteristics and the corresponding strength envelopes and calculated <br />safety factors for each of these baseline conditions were presented in Amendment No. 3, <br />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 fallowing sections along with a summary of [he geologic <br />' mapping performed on the new final highwalls established in 1499. <br />5.02 East Side of the Central Quarry <br />The highwalls and benches are aligned a[ approximately N10~W [o N20~W. The rock type is <br />primarily granite gneiss with mafic and felsic intrusions (felsite dikes and pegmatites). This <br />' rock is primarily competent rock (unconfined compressive strength greater than 15,000 psi) <br />with localized zones of poor rock. <br />The primary joint set is orientated along the foliation of the rock mass. The primary joint set <br />' orientation varies along Bench A and B, corresponding with the varying orientation of the <br />foliation due to several sets of anticlinalJsynclinal structural features in the rock mass. [n <br />general, the foliation dips out of the highwall in either a northwest or southwest direction. <br />' The joint set strike is sub-parallel to sub-perpendicular to the mining face and the dip angle of <br />is approximately 25~-50~. The two dominant joint sets related [o foliation are shown in Table <br />1. Spacing of joints in the primary joint set typically ranges from several inches to <br />' approximately 10 ft. Joint surfaces are typically tight and appear fresh to slightly weathered. <br />Joints are typically discontinuous. <br />IJ <br /> <br /> <br /> <br />(i \FRU1 FCTS\2f1?p(1 MUrncun Quafry\(1p5\ I V!i9\neu'UOi na~kup dik <br />1 <br />