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Whv no On-site Testine: Since no active mining is occurring at the proposed quarry site, <br />bringing and operating heavy equipment at the site without a permit was not practical or <br />legal. <br />Basis of Conclusions: Since onsite testing with heavy equipment was not feasible at this <br />time, it is very customary for engineers to rely on data from other sites and experience from <br />prior work. <br />Figure 1: This figure, based on the scale shown, inaccurately shows the mining occurring <br />within about 115 feet of the crest of the Rollins sandstone. The actual distance between the <br />mining limit boundary and the crest of the Rollins sandstone formation, based on USGS <br />topographical data, is over 300 feet. <br />Figure 2: The vibration wavelengths and frequency calculated in this figure are very <br />inaccurate and misleading. The wavelength of 1,850 feet was calculated by doubling the <br />distance between the source and point of concern. This is an erroneous calculation. At this <br />site where the lowest frequency of motion measured by equipment was 14 Hz, assuming a p- <br />wave velocity of 8,000 ft/s (same used by Mr. Flinn), the wavelength would be 571 feet <br />[8,000 / 14]. Hence the 4-Hz motion in Mr. Flinns calculations is based on a wavelength <br />inflated by more than a factor of three times the actual wavelength. This calculation has no <br />meaningful purpose and is not technically supportable. <br />Gregory D. Lazear Letter -April 11, 2006: <br />Rangeland Description: Already answered in response to Flinn Letter. <br />Omission of Homes: In Figure 1, of the author's report, homes that were shown on site map <br />drawings provided to the author were included. While the site map does show the homes <br />closest to the sandstone bluff, other homes were no intentionally omitted. <br />Experimental Procedure: The vibration monitoring performed by PreSeisTek, Inc. at the <br />Austin Quarry was done in rigorous conformance with vibration guidelines developed by the <br />Vibration Section of the InternafionaI Society of Explosives Engineers (ISEE). These <br />industry monitoring standards are provided in Attachment I. <br />Sensor Freuuency Range: In his genera] comments, Mr Lazear states that the recording <br />equipment has aloes-frequency cutoff of 15 Hz. While this may be true for geophones <br />commonly used for seismic exploration work in the oil and gas industry, in this case, the <br />flat-response frequency range of the vibration transducers, conforming to ISEE standards, is <br />2.0 to 250 Hz. Hence, low-frequency motions, had they occurred, would have been <br />measured accurately. Average frequency of motion for the testing was over 35 Hz. <br />REVEY Associates, Inc. Page 2 of 13 4/19/06 <br />