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Review of Blasting Operations at Robinson Brick Company's Siloam Cla} Mine <br /> the maximum charge weight per delay. The log-log linear relationship between scaled distance and <br /> predicted peak particle velocity (ppv) is shown in equation 2.1 on page 8 of this report. <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. <br /> Waveform - Seismic Signal <br /> Velocity of Particle Motion measured <br /> with respect to time <br /> Peak <br /> o AMPLITUDE <br /> > BASE <br /> LINE <br /> ti <br /> 1 CYCLE <br /> T <br /> DURATION <br /> TIME # <br /> Figure 2.2—Particle Vibration Time History <br /> Vibrating ground motion can be characterized by measuring particle displacement, velocity, <br /> acceleration, and vibration frequency. <br /> Displacement is a measure of ground particle travel distance or directional position with respect <br /> to time. Particle velocity measures the speed of movement while acceleration is the rate of <br /> velocity change. Vibration frequency is a measure of how many oscillations a ground particle <br /> makes in each second of time. <br /> GEOTEK&Associates, Inc, Page 5 January 99 <br />