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P.03 <br />Harding Lawson/West Elk Gob Pile Rock Testing Page 2 of 4 <br />• The HQ hole that you have drilled reached 82', the initial portion of which penetrated mainly river <br />gravels. The hole encountered highly weathered Mesaverde at 62', which became less weathered <br />by 65' and less weathered still by 75', yielding a total of 20' of core. The test specimens were <br />prepared from bedrock core samples from within the interval from 62' to 82'. The core was air <br />dried, but not completely dried out. <br />SPECIMEN PREPARATION <br /> <br />Unconfined compression specimens were cut to lengths between 2 and 2.5 times their diameter, <br />using water as a coolant, then ground on the ends to meet ASTM requirements. Prepared <br />specimens were kept in ziplock bags urrti! testing, and although far from saturated, they contained <br />some moisture when tested. As-tested densities were measwed prior to mechanical testing. <br />Direct shear specimens were cut to testable size from the HQ wre using water as coolant, then <br />individually potted in high strength grout to St the test machine. These were also stored in <br />ziplock bags until tested, and also contained some small amount of moisture when tested. <br />TESTING <br />Unconfined compressive strength tests were tun on 3 sandstone specimens, according to ASTM <br />D-2938. Axial force data was collected by a stram-gaged load cell. <br />Direct shear tests were run on 4 specimens of rock discontinuities. Shear load data was collected <br />by a strain-gaged load cell, and shear displacement data was collected by an LVDT Four runs, at <br />50, 100, 200, and 400 psi normal stress, were run on each specimen, except for one which <br />disintegrated during the 100 psi run. <br />Transducers were al! recently calibrated. All data was collected by computer and saved directly to <br />hard disk. <br />DATA REDUCTION <br />Densities were calculated from the measured dimensions and weights of prepazed compression <br />specimens. <br />Unconfined compressive strengths were taken as the highest axial forces supponed by the <br />specimens divided by the initial areas of the specimens, aRer which peak the specimens lost some <br />or all of their ability to support load. <br />Direct shear strengths were calculated from the appropriate shear loads sustained at each normal <br />• stress, divided by the initial discontinuity areas. Friction angles were determined by plotting <br />shear stress vs normal stress for each specimen. <br />R6CK7ECI1 7444 Platinum Circle, WM talon, t1T S40a4 i3Jl u55S222 <br />