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wave propagation phenomena that produce amplitude amplification. The Revey report <br />will greatly underestimate expected amplitudes of ground motion if these propagation <br />effects are present. <br />6) There is no analysis of the impact of vibrations upon stability of fractured blocks <br />in the Rollina sandstone cliff based upon principles of rock mechanics, engineering <br />analysis, or risk analysis. <br />The Revey report simply dismisses effects of vibrations as insignificant and <br />"undetectable" without using standazd methods of risk analysis to assess the effect of <br />vibrations on stability of blocks in the highly jointed Rollins sandstone cliff. Support for <br />the conclusion that vibrations would have no effect on the probability of a rock fall is <br />based upon comparisons with: 1) dilation of cracks in brick wails in Frankfort, Ky. due to <br />heating and cooling cycles that operate on very different time scales (diurnal to years); 2) <br />earthen dam designs to withstand earthquakes; and 3) a site neaz Castle Rock, Co. which <br />did not have slope failure. These comparisons have no logical relevance to the stability of <br />the specific cliff face of interest. A hazard analysis should use technically and statistically <br />sound analysis based upon geophysical and rock mechanics principles, and should <br />incorporate acoustic modeling of the specific site to provide an assessment of the risk of a <br />mck fall being induced by vibrations from heavy equipment. This has not been provided <br />by the Revey report. <br />CONCLUSIONS <br />The Revey report has major technical flaws that undermine the credibility of the <br />conclusions, including the lack of similarity of the experimental site to the proposed <br />quarry location in Coalby Canyon, omission of critical documentation of field methods, <br />questionable regression techniques, no analysis of errors, failure to model the nature of <br />seismic energy propagation that could be generated at the proposed quarry site, and a <br />complete lack of analysis of risk. Data presented is not relevant to the proposed quarry <br />site, and the stated conclusions are not supported by evidence in the report. In my <br />opinion, the Revey report does not constitute a satisfactory geohazazds analysis. <br />Gregory D. Lazear <br />Geophysicist <br />Senior Research Scientist, Retired <br />Conoco, Inc. <br />