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1100318 R0T0 0811 JRW1 25 <br />(Appendix 39). Folding reflecting north-south compression is also present in Area H, as shown <br />on cross section A-A'. <br />Minor faulting is also present within the fault-bounded block, particularly near the south end of <br />Area H. In this area, a number of northwest-striking high-angle faults are mapped that project <br />to the face of the quarry in the area of the recent landslides (see geologic map, Appendix 39). <br />These faults appear to have formed as a result of north-south compression acting along the <br />southerly end of Area H. Although none of these faults appears to display substantial <br />displacement, the faults project into a portion of the slope that is approximately coincident with <br />the southerly margin of the displaced December 2, 2008 landslide mass. These minor faults <br />therefore likely formed a structural weakness in the slope face that contributed to the <br />configuration of that landslide. <br />5.2.2 Subsurface Investigation <br />5.2.2.1 Overview of Investigations Performed <br />Two phases of field investigation were performed to evaluate the subsurface conditions in the <br />Pikeview Quarry. The initial investigation was performed in early April 2011 and consisted of <br />advancing four air percussion borings and excavating eight test pits/trenches. The air <br />percussion borings were advanced to depths of 67 to 70 feet below ground surface using a <br />tracked drill rig. The trenches were excavated using an excavator or a bulldozer. The trenches <br />generally extended to a maximum depth of about 5 feet below ground surface. The locations of <br />air percussion borings EXAP-1 through EXAP-4 and trenches TR-1 through TR- 8 are shown <br />on the geologic map (Appendix 39). The logs of the air percussion borings are included in <br />Appendix 41. The test pits were photo documented; the photos of these excavations are <br />included in Appendix 3 of this report. <br />A supplementary field investigation was performed in May 2011 that consisted of advancing <br />five rock core borings, four air rotary borings, four air percussion borings, three hollow stem <br />auger/core borings, and one rotary wash boring. The locations of rock core borings EXC-1 <br />through EXC-4 and EX-G, air rotary borings EXAR-1 through EXAR-4, air percussion borings <br />EXAP-5 through EXAP-8, hollow stem auger borings EXB-1 through EXB-3 and rotary wash