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1 <br /> in B105 was all excellent with RQD ranging from approximately 85 <br /> to 100 percent, which bodes well for highwall rock quality in the <br /> ' proposed reservoir horizon below approximate El 6475. <br /> In B 104, inclined at 40 degrees through the head scarp area, several <br /> red clay gouge features were encountered in the core. These are <br /> thought to represent splays of the overall slide plane feature exposed <br /> in the fourth highwall below. Clay with gravel and clay layers were <br /> encountered at inclined depths of approximately 27 ft, 33 ft and 42 ft. <br /> The clay seam encountered at 42 ft in B 104 appeared to correlate with <br /> a similar clay seam at approximately 40 ft in Boring B 101 and both <br /> ' were assumed to be representative of conditions in the basal slide <br /> plane. Samples of the clay gouge were submitted for laboratory <br /> testing along with intact rock cores to obtain data for modeling the <br /> slide failure and designing a repair. <br /> 4. Laboratory Testing <br /> ' Laboratory testing performed as part of the slide analysis consisted of <br /> 1)ten unconfined compressive strength tests (ASTM 2938) on intact <br /> ' rock core specimens; 2) one direct shear test using the Robinson <br /> Shear Box of a sample of the red clay gouge thought to be <br /> representative of the slide plane; and 3) five index tests of clay gouge <br /> ' encountered in the borings consisting of Atterberg Limits tests <br /> (ASTM D4318). All laboratory testing was performed by Advanced <br /> Terra Testing and the results are in Appendix C. <br /> ' Compressive strength results ranged over about two orders of <br /> magnitude from approximately 350 psi to over 33,000 psi for core <br /> samples representing the full range of rock types encountered in the <br /> ' borings. These data confirm the highly variable nature of the rock <br /> mass being mined. In general, the lower strengths correlate well with <br /> weaker rock types such as schist, weathered hornfels and brecciated <br /> ' granite porphyry, while the higher strengths correlate with deeper, <br /> fresher samples of granitic gneiss. The average value from the tests <br /> without regard to rock type and their percentage occurrence is <br /> ' approximately 10,000 psi. <br /> The joint direct shear test on the red clay gouge was a three point <br /> ' modified COE method test of normal stress versus residual shear <br /> stress. A plot of normal versus shear stress for the data results in <br /> values of approximately 8 psi for effective cohesion("C") and 20 <br /> degrees for internal friction angle, or phi (0). The residual shear <br /> strength indicated for the clay gouge from these data is consistent with <br /> failure along a daylighting shallow dipping failure surface inclined at <br /> ' only 20 to 25 degrees. <br /> ' 12 G:\PROJECTS\20200\002\96ANNRPT.WPD <br />