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i 1 1 1 The primary joint set is orientated along the foliation of the rock mass. The primary joint set orientation is typically consistent with occasional variations corresponding with the varying orientation of the foliation due to several sets of localized anticline/syncline structural features in the rock mass. In general, the foliation dips into the highwall in either awest/southwest direction. The joint set is parallel to sub-parallel to the mining face on the western side, perpendicular to sub-perpendicular on the northern side, at a dip angle of approximately 25~- 50~. The primary joint set related to foliation is shown in Table 3. Spacing of joints in the primary joint set typically ranges from several inches to approximately 3 ft. Joint surfaces are typically tight and appear slightly to moderately weathered. Joints are very continuous in certain locations, and discontinuous in other locations. Table 3. Dominant Joint Sets Along the North Side of the North Quarry Joint Set Strike Dip and Dip Direction Significance Primary N70W NOOW 25W SOW Low (wlfoliation) Secondary N60W NOOW 70SW 90 Moderate N20E N50E SOSE 70SE Low Two dominant secondary joint sets are present. These joint sets are orthogonal to each other, with strike orientation of one in a northwest direction, the other in a northeast direction. These joints dip steeply to near vertical out of the mining face. The secondary joint sets are shown in Table 3. Spacing ofjoints in the secondary joint set typically range from several inches to approximately 5 feet. Joint surfaces are typically tight and appear slightly weathered. Joints are both continuous and discontinuous. Slope failures included numerous, relatively small block and wedge failures, generally less than 10 feet in length, and relatively larger slab failures of up [0 40 feet wide and 50 feet wide where primary jointing where continuous and dipping out of the slope, intercepted secondary jointing. The small failures are as expected for the highwatl and cause localized operational inconveniences. The larger failures could be an indication of a substantial hazard that exists on the slope The overall condition of the slope on Benches 6 to l3 between "competent" and "poor" with the majority of benches 8 and 9 having a "competent" condition. A fault or major fracture exists that appears to have a strike parallel to and dips into the mining face (Plate 2, Location L). Several other major fractures exist along the slope that show weathering and may potentially cause_major slope instabili~(Plate 2, Location G and I). Currently, the rock mass along these fracmres appears stable. ~ms~ ~ ~ ~ ~~ ~~ G.\ NRO1 CC1 ti\202W Piorrimn Quarp \~$\ 1971\neu gimarkup Juc to