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• <br />w <br />STATION <br />IDENTIFIER LATITUDE LONGITUDE <br />BWK 38.928 107.537 <br />FGH 38.948 107.536 <br />LLM 38.857 107.461 <br />MCD 38.881 107.474 <br />MFB 38.956 107.559 <br />SPG 38.872 107.425 <br />SEF 38.874 107.390 <br />TCR 38.982 107.564 <br />WFW 38.901 107.424 <br />WTM 38.941 107.591 <br />Table 1 <br />ELEVATION DELAY NAME OF STATION <br />(feet) TIME <br />6701 0.037 Bowie King Mine <br />7201 0.133 Freeman Gulch Hubbard <br />8240 0.230 Lion Mesa <br />7274 0.103 Minnesota Creek Dam <br />7924 0.190 Middle Forest Boundary <br />8174 0.289 South of Poison Gulch <br />8667 0.370 South on East Flatiron <br />8483 0.204 Terror Creek Dam <br />8433 0.258 West Flatiron West <br />7954 0.104 West Tower Mountain <br />By October, 2005, five stations of the monitoring system were in operation near the Bowie Mine <br />with a radio network transmitting most stations to the mine (near the BWK station). The additional <br />instruments were added to the network and were operational by July 1, 2006. Reconfiguration of <br />the radio network to transmit all signals to the Paonia airport took place during the third quarter of <br />2006 (July-September, 2006). During the second quarter events recorded on the triggered <br />network were obtained for all of the 91 days in the quarter. Portions of the Earthworm computer <br />program of the USGS are used to record the multistation data in event files. Data were available <br />at the Spokane offices of NIOSH for daily review. <br />The following table gives the correspondence between the amplitude of seismic signals, measured <br />in digital counts, and acceleration. The vertical acceleration due to the pull of the earth is <br />abbreviated as'g'. The units are given in terms of 10-6g or micro g's. Typical noise levels on the <br />recordings are 5-15 digital counts, a figure that will decrease as electronic noise sources are <br />eliminated. Of course ground motions such as wind events, traffic, and animals will continue. <br />Multiple stations mitigate the response to these noise sources as the 'noise' events typically occur <br />on one or a few stations. <br />TABLE 2 DIGITAL COUNTS vs. ACCELERATION DUE TO GRAVITY <br />DIGITAL COUNTS MICRO g <br />(10.6 of acceleration of <br />gravity) <br />25 0.75 <br />50 1.50 <br />100 3.00 <br />200 4.96 <br />1000 29.80 <br />5000 149.01 <br />10000 298.02 <br />335544 10000 1% of <br />• <br />