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AET #20-04834 - Page 2 of 4 <br />be conducted in a more urban setting, closer to existing structures or near residential <br />neighborhoods where ground vibrations may be of a concern. Because of this, Shafer requested <br />AET to perform vibrationmonitoring at various distances from both the primary rock �u�h�[ and <br />the secondary rock crusher. The distances chosen to monitor were at 50', ��' , 150' and 200' <br />north of rock crushing activities. <br />.. �� _ N �4 ,. ��N ; ��J . <br />Ground vibrations were monitored on December 2, 2004, using an Instantel DS477 Blastmate � <br />seismograph. The seismograph consists of a geophone, keyboard, plotter, and liquid crystal <br />display. The unit was programmed to self trigger if the peak particle velocity (PPV) exceeded <br />0.005 inches per second (inls) at any time during our monitoring. Monitoring was performed at <br />each of the selected distances for time periods of two to five minutes. <br />Prior to each monitoringperiod, the geophone was aligned and leveled on the ground surface, and <br />the monitor was turned on. Peak particle velocities and Frequencies were recorded for each <br />monitoring period and printed in hard copy. The resultant data was reviewed and the highest peak <br />garticie velocity from each monitored distaalce have been listed in the following tabulations. <br />Table 1. Vibration Monitoring Results on December 2, 2004 <br />Primary Rock Crusher <br />Time PPV Frequency Approximate distance to <br />�»��} �Fif� rock crusher (ft) <br />10:12 AM 0.068 13 50 <br />L�;15 A� �.0�4 L� ]� <br />i�:�4 �� c�.t��� - 1� 65� <br />il}���x A� �).�9 13 �Ot� <br />