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Review of Blasting Operations of Summit Brick <br />ANALYSES of BLASTING IMPACTS, cont' <br />Displacement is a measure oC ground particle travel, with respect to distance or directional <br />position and time. Particle velocity is a measure of the movement speed while acceleration <br />is the rate of velocity change. The vibration frequency is a measure of how many <br />oscillations a particle makes in each second. The U.S. Bureau of Mines studies (Bulletin <br />656, 1979 and ItI 8507, 1980) researchers have recommended conservative criterion that <br />most government agencies, including Colorado, have adopted in commercial blasting <br />regulations. Governmental agencies and private sector researchers have conducted <br />considerable study to determine how ground motion might influence the stability of rock <br />and soil, or cause damage to stmctures. Regulations have been established with very tight <br />limits on peak particle velocity (ppv), and in some cases frequency, to prevent blast-induced <br />ground motion from even approaching damage thresholds. Other researchers have <br />evaluated the effects of ground motion on people, buried pipelines, water wells, and many <br />other structures. <br />2.1-2 Potential for Damage to Structures from Blast-induced <br />Ground Motion: <br />The United States Bureau of Mines, in RI 8507 (1980) made the following conclusions <br />regarding the potential for damage caused by blast-induced ground motion. <br />"P~actical safe criteria for blasts that generate low fieguency ground vibrations are 19 mmis (0. 75 inls) <br />for modem gypsum board tenures and 12.7 mm, is (0. 50 inls) for plaster on lath inieriors. Far frequencies <br />above 40 Hz, a safe parlide velocity maximum of 5 I mmis (2. 0 inls) is recommended for all houses. <br />It should be noted that the USBM RI 8507 recommendations are designed to prevent even <br />threshold damage in residences of lower-quality construction. Threshold damage was <br />defined as: <br />"77ereshold damage was d~ned as the occurrence of cosmetic damage; that is, the most superficial interior <br />crackang of the type that develops in all homes independent of blaming. <br />]3 <br />