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BLACK OBSIDIAN MINE BLAST PLAN <br /> I. Blast Schedule Notification: <br /> A Colorado Quarries Inc, 270 S 15th St, Canon City, CO 8121 <br /> B 1/2 mile north of Silvercliffe, CO on Emery Street <br /> C Days and times vary depending on crushing production. On average, one blast <br /> per week produces sufficient material for crusher. <br /> D Access to blast area is controlled by blocking access road to site. Mine foreman <br /> performs visual inspection of the blast area for unauthorized persons or <br /> vehicles. <br /> E Horns are primary means of warning signals used prior to shot and post shot. <br /> F After shot is loaded and ready, all mine employees are notified to leave area to a <br /> safe site. Custer County Sheriffs Department and Custer County Fire <br /> Department is notified of every shot, which has been the procedure for more <br /> than 15 years. After blast site has been cleared by blaster, horn is sounded for <br /> the ALL CLEAR and mine employees are allowed to enter mine area. <br /> II. Pre-Blast Surveys <br /> A There are two structures to the N, NE of mine site, a distance of 1069' to the <br /> Cherry residence and a distance of 1199' to the Walker residence. <br /> B Colorado Quarries has been mining this pit for 42 years. Both of these <br /> structures are more recent. There has been no issues or complaints from these <br /> structure owners for the past three decades. <br /> C Map included showing structure locations in relation to the mine site. <br /> III. Blast Plan <br /> A Ground Vibration. <br /> The United States Bureau of Mines (USBM) and Office of <br /> Surface Mining and Reclamation (OSMRE) standard for maximum allowable <br /> Peak Particle Velocity (PPV)for ground vibration, at a distance of 301 to 5000' <br /> not to exceed 1.00 inches per second (in/s) at a frequency of 20.5 Hertz (Hz). <br /> On 12/22/21 Colorado Quarries monitored a blast. Location of monitor was 860' <br /> east and north in line with closest inhabited residence which is 1069' from mine <br /> pit. The ground vibration (PPV) at this point measured 0.0406 inches per second <br /> (in/s). This well below maximum allowable of 1.00 in/s. <br /> B Air Blast <br /> The United States Bureau (USBM) and Office of Surface Mining and <br /> Reclamation (OSMRE) standard on arblast or Peak Sound Pressure Level (PSPL) <br /> maximum allowable is 133db (L). <br /> On 12/22/21 Colorado Quarries Inc monitored a blast. Monitor location was 860' <br /> north and east of mine site in a direct line of the closest inhabited residence <br /> (Cherry) which is a distance of 1069'. The air blast (PSPL) recorded 118.5 db (L) <br /> which is well below allowable standard of 133 db (L). <br /> Extracting material at this site is by done vertically to a given depth. The walls <br /> of the pit as well as natural topography will create barriers for air blast. <br /> C Controlling Adverse Effects of Blasting <br /> Having qualified management and experienced blaster on site is first step of <br /> controlling effects of blasting. How the shot is loaded and delayed is critical to <br /> controlling vibrations and fly rock. Mine personnel need to be diligent in <br /> observing surrounding areas for unauthorized persons or vehicles entering <br /> restricted areas during blasting operations. it is the requirement of the blaster to <br /> insure all mine personnel have cleared mine sit and do not return until the all <br /> clear is given. <br />