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Review of Blasting Operations at Denver Brick Company's Golden Mine <br /> These ground vibrations are elastic waves, meaning that the ground particles move as the wave <br /> passes and quickly come to rest exactly as they were before the waves arrived. The average <br /> person is quite sensitive to ground motion, and can feel vibration at levels several orders of <br /> magnitude lower than motion at damage threshold levels. Ground particle motion occurring at <br /> velocities as low as 0.50 mm/s (0.02 in/s) can be detected by the human body. So people will <br /> "feel" blasting during almost every shot, but their homes and structures will not be damaged. <br /> 1 CYCLE Velocity of Particle Notion or Ar-Overpressure Platted <br /> wM respect to Trne <br /> J <br /> TIME 0111110- <br /> rr <br /> A <br /> d FAmplitude <br /> d +1-) <br /> "-Swj- / <br /> Event Duration <br /> Figure 2.2 -Vibration or Air Overpressure Time- Intensity History Plot <br /> The residential structures located 800 feet or more away from the Golden Mine will not be <br /> damaged using a conservative particle velocity limit of 0.5 in/s and keeping a charge weight per <br /> delay to 50 pounds, it will keep vibration below 0.2 in/s. <br /> For instance, from the U.S. Bureau of Mines studies (Bulletin 656, 1979 and RI 8507, 1980) <br /> researchers have recommended conservative criterion that most government agencies, <br /> including Colorado, have adopted in commercial blasting regulations. To prevent blast induced <br /> ground motion from even approaching damage thresholds, these regulations establish <br /> extremely cautious limits on peak particle velocity (PPV). Some damage prevention regulations <br /> also consider the frequency of ground motion. Other researchers have evaluated the effects of <br /> ground motion on people, buried pipelines, water wells, and residential/commercial structures. <br /> In this investigation, Stanto Group Inchas analyzed the potential risk of blast induced vibration <br /> damage or disturbances to structures and persons located near the Golden Mine. <br /> 2.1.2 Potential for Damage to Structures from Blast Induced Ground Motion: <br /> The U.S. Bureau of Mines, in RI 8507 (1980) made the following conclusions regarding the <br /> potential for damage caused by blast induced ground motion. <br /> "Practical safe criteria for blasts that generate low frequency ground <br /> vibrations are 19 mm/s (0.75 in/s) for modem gypsum board houses and <br /> 12.7 mm/s (0.50 in/s) for plaster on lath interiors. For frequencies above <br /> 8 <br />