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o Transit Mix Concrete Co. <br /> 444 E. Costilla Street, Colorado Springs,CO 80903 Office: (719)475-0700 Fax: (719)475-0226 <br /> If the misfire hole or holes cannot be safety reblasted, the immediate area of the misfire <br /> will be secured (ie a new blast site established) and all mining personnel warned of the <br /> hazard and its location. The immediate area of the misfire will be carefully excavated <br /> under the supervision of a licensed blaster or quarry manager until the misfire is <br /> remediated. <br /> Blast Monitoring Procedures <br /> As part of Hitch Rack Ranch Quarry's Blasting Plan, all blasts will be monitored using <br /> several methods. They are as follows: <br /> • Blasts will be video recorded, if weather conditions permit. <br /> • Seismograph instrument(s) will be used to measure and record ground vibrations <br /> (peak particle velocity—inch per second (ips)) and air overpressure (decibels <br /> (db)) from blasts. The proposed maximum peak particle velocity will be one half <br /> (1/2) inch per second measured at the seismograph instrument's location set up <br /> nearest to the closest non Transit Mix owned structure (a residence). All attempts <br /> will be made to keep peak particle velocities well below the proposed maximum <br /> allowable limits. <br /> o Seismograph Monitoring Equipment: <br /> ■ Will have a flat frequency response between 2 and 250Hz for <br /> particle velocity. <br /> ■ The digitizing sampling rate for peak particle measurements shall <br /> be at least 1,024 samples per second. <br /> ■ Shall be capable of performing a self-test of velocity transducers <br /> and printed event records shall indicate whether or not the sensor <br /> test was successful. <br /> ■ Shall be capable of recording particle velocities with intensities <br /> ranging from 0.02 to 5.0 inches per second. <br /> ■ Shall be calibrated by a service center approved by the <br /> manufacturer within at least two years of the time of use. <br /> Certificates documenting date of calibration, issued by the <br /> approved service center, shall be kept by the user. <br /> ■ Shall be capable of printing hard-copy reports showing the date <br /> and time of monitoring, the maximum peak particle velocity (PPV) <br /> measurements, and plotted PPV-time waveform plots. <br /> o Seismograph monitors will use microphone(s)to measure and record air <br /> over pressure from blasts. The proposed maximum decibel (dB) level for <br /> air over pressure will be 130 dB measured at the seismograph instrument's <br /> location set up nearest to the closest non Transit Mix owned structure (a <br /> residence). Colorado State regulation for max air over pressure (dB) level <br /> is 133 dB. All attempts will be made to keep air over pressure levels well <br /> below the proposed maximum allowable limits. Seismograph Monitoring <br /> Equipment <br /> 14 <br />