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I:valu36011 of Vibration at the Benson Brothers Red Shale Ouarry <br />10 <br />8 <br />6 <br />on <br />C 4 <br />F-- <br />U 2 <br />0 <br />W <br />> <br />W o8 <br />J <br />0 6 <br />Of 0.4 <br />a <br />0.2 <br />0.1 <br />USBM RI 8507 Safe PPV Curves - Dashed Lines <br />50.8 mm's <br />x(20 in/s) <br />...................... <br />e• <br />0.75 in/s 40 <br />............................... p : Plaster & Lath r' <br />..............................• <br />............ <br />p9°:O' ? 0.50 irYs <br />so . <br />Measured <br />t? PPV Range <br />2 4 6 e 10 20 'J0 40 60 80 ton <br />FREQUENCY, Hz <br />Figure 2 -- USBN1 "Safe Level" vibration curve from R1 8507 <br />Vibration Data Analysis <br />The highest vibration reading occurred on August 12, 2008and likely was caused when <br />the battery was checked for power. Since the peak measured intensity of construct 10n- <br />activity ground vibration was 0.34 inches per second (inis), which is less than the 0.5 fn's <br />safe level recommended by the USBN1, it is reasonable to conclude that any vibration <br />caused by the heavy equipment will not register levels of any significance at the rock <br />bluffs or near any properties. <br />Respectfully submitted, <br />Sara J. Nation <br />PreSeisTek, Inc. <br />PrcSeis I A. Ink-. <br />Pace 4 of 4 <br />S 21 8 2008