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~~ ati7eeon 11460 W. 44th Ave., Suite 6 <br />M inin Wheat Ridge, Co 80033 <br />303.456.5 <br />• OnlU~nlti Fex 303~58.5~ <br />October 24, 1997 <br />_ Mr. Rick Batista <br />Blackwing, Inc. <br />P. O. Box 6467 <br />Woodland Park, <br />Flagstaff, AZ 86001 <br />Re: Blast monitoring at Red Mountain Quarry, 10/17/97. <br />- Dear Mr. Batista; ~Ny® <br />Matheson Mining Consultants (MIviC) monitored one quarry pro coon <br />blast on October i7, 1997 at Rocky Mountain Materials Red ~6iea-Quarry <br />- in Fremont County, Colorado. Two Instantel Blastmate III digital blasling <br />seismographs were used to monitor the blast. One seismograph, BA5552, <br />was placed at the ranch house, 3131 Barrett Road. The second <br />- seismograph, BA5738, teas placed ai the next closest house, 3103 Barrett • <br />• Road. Neither seismograph recorded the event with trigger with levels at <br />0.05 inches per second (ips) and 0.04 ips respectively, the air channel <br />trigger was set at 129 dBL on both instruments. Attached to this letter are <br />the monitor fogs from each seismograph showing they were monitoring at <br />_ the shot time and a copy of the blast report showing the number of holes, <br />total charge weight and maximum charge weight per delay. <br />_ The ground motion at the two houses was less than the seismograph <br />trigger levels, 0.05 ips at the ranch house and 0.04 ips at the second <br />house. The air overpressure at both locations was less than 129dBL. At <br />- both locations the seismograph was placed within ten feet of the house <br />between the house and the blast location. <br />Sincerely, <br />~. ~~ ~ <br />Colin M. Matheson <br />Mining Engineer <br />• <br /> <br />