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.d <br />khite Lnginecring Associates, Inc. <br />Report t;o. 79219-D <br />Utah International, Inc. <br />June 18, 1979 <br />Page 3 <br />• vibration study. <br />Reliable measurements were obtained at each station For both blasts. <br />The measurements are listed in the attached sunmary tables along with other <br />pertinent data. <br />Discussion and AnaIvsis <br />The attached Tables I, II and III summarize the information pertinent <br />to this study. Votes of explanation are noted on the tables. <br />Table III is a reiteration of data obtained from the two previous <br />studies conducted at this mine. <br />Several graphs have been prepared based on these data. In Graph I, <br />we have plotted the peak particle velocity measurements, including those obtained <br />• from the previous studies, as a function of D/(TM)1/3. For this graph we used <br />the maximum pounds per delay as stated on the blasters logs for Shots 1 and 2 <br />on January 10, 1979. While plotting this graph, we noted the slope and the <br />intercept changed by a good margin from the previous studies. This led us to <br />J • carefully evaluate the airing diagrams of the two shots fired on January 10, <br />1979. <br />Our study of these wiring diagrams leads us to believe that the <br />effective charge weight per delay should be on the order of two-thirds of the <br />total explosive load in each blast fired in the time frame of 42 milliseconds, <br />and the total was detonated in G9 milliseconds for Blast 1, and in 60 milliseconds <br />for Blast 2. By way of contrast, the blast monitored in the study of September <br />16, 1977, used 17 millisecond delays and required more than 1000 milliseconds to <br />completely detonate. <br />Because of this evaluation, we recalculated the scaling factors using <br />the larger charge weights per delay. Both the larger charge weights and the <br />new scaling factors are listed in parentheses on Tables I and II. By using this <br />larger charge weight, we have plotted Graph lA wh.ich does appear to conform to <br />the previous equation developed ;is a result of t~e'.`data from the two previous <br />studies. <br />The new Federal regulations ti:~vc established a limit for blasting <br />vibrations. They have chosen to use the maximum charge weight per delay as <br />the guiding limiting charge. Graph fI and fIA show all of the measurements as <br />L-3 <br /> <br /> <br />