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Review of Blasting Operations at Denver Brick Company's Golden Mine <br /> natural barrier between the blasting operation and the home which will reduce the overpressure <br /> impact on the home. <br /> Residential Buildings: <br /> Despite studies from RI 8507 (Siskind, et al, 1980)and State of Colorado Rules would allow <br /> vibration levels from 0.5 to 2.0 in/s, factors. Denver Brick Company, plans to limit blast charge <br /> weights so PPV at all offsite structures does not exceed 0.2 in/s. <br /> Existing residential buildings might be located within 800 feet, however, blasters can use <br /> standard methods to reduce charge per delay as needed to design and execute compliant <br /> blasts. Keep PPV below 0.5 in/s, the minimum scaled distance should be 55 ft/lb'12. With 800 <br /> foot distance to the closest residential structure it is below 0.2 in/s. <br /> 2.4 Pre-Blast Activities <br /> Prior to blasting a variety of non-explosives related, but regulatory related activities will need to <br /> occur: <br /> 1. Home-owner Notifications- Each homeowner with reasonable concern or potentially <br /> affected by the blasting activities (generally within a 800 foot radius) must be notified, <br /> preferably in writing, but verbal notification is acceptable about blasting occurring within <br /> the mining operational area. The home-owner notification will contain the address or <br /> known location of the blasting activity and an estimated timeframe the blast will occur. <br /> 2. Seismograph service coordination - From the blasting contractor's experience with <br /> respect to distance from occupied structures and quantity of explosives being used per <br /> detonator, a seismograph service may be required to be used during a blasting event. If <br /> a seismograph service is required then the seismograph service provider has 24 hours <br /> to notify the contracted blaster and the mine owner a seismograph report. <br /> 3. Blast site security-the blast area is the area that the blasting contractor's experience <br /> would dictate to be potentially dangerous for personnel and equipment to be in. The <br /> blaster-in-charge is responsible for all roads to be blocked if potential access into the <br /> blast area is determined. Personnel are commonly used to block traffic and other <br /> personnel from entering the blast area. Blast site security is only required 10-15 minutes <br /> before the blaster in charge is ready to fire the shot. <br /> 4. Blasting signals- Blasting contractor will use a horn or another device to notify those in <br /> the blast area at the time of the shot. Commonly, a 5-minute pre-blast warning will be <br /> sounded, then a 1-minute pre-blast warning will be sounded and finally Fire-In-The-Hole <br /> call will be made over the communication devices used to control the blast area. The <br /> Blaster-In-Charge is the one responsible for going through this countdown and will <br /> ensure all personnel and equipment in and around the blast area are at a safe distance <br /> from the shot. <br /> 15 <br />