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DON HARRIS ~: ASSOCIATES <br />2225 Beckham K'ay • <br />Hayward, California 94541 <br />(415J 886-'856 <br />VIBRATION S~ SOUND STUDY <br />RELATED TO <br />COLOWYZ~~OAL'-t''O~~PANY <br />MEEK; R COLORADO <br />ON <br />TUESDAY JUDIE 19,1979 <br />and <br />WEDNESDAY JUNE :?Oz1979 <br />PURPOSE: <br />The purpose of this study Baas to measure vibration <br />and air blast overpressure levels fron t:ao blasts initi- <br />ated at the Colowyo Coal moo, operation during the after- <br />noons o` June 19 and 20, 1979 as a result of s*-atements <br />from several near-by residents that they could both hear <br />and feel blasts created by Colo~oyo Coal. <br />THE BLASTS: • <br />Three blasts were to leave been monitored during this <br />visit. However, the first area lead not beer complztely <br />drilled out by Monda;~ 5-18-79 and this blast was delayed <br />until Tuesday. Therefore only two shots were monitored. <br />Pertinent data on leading and firing of these blasts <br />are tabulated beloca; <br />Date <br />Time <br />Number Holes <br />Hol= Dian'ter <br />Dept's <br />Burden <br />Spac=ing <br />Total >;splosive <br />Delays <br />Max. Hole:~ldelay <br />Max, lbs./delay <br />Stemming (ft. ) <br />Weight (lbs.) <br />b-19-79 <br />4:03 P. M. <br />91 <br />9'7/8 <br />37 <br />21 <br />2L <br />41,717 <br />MS 17 <br />12 <br />5,501 <br />20 <br />6-20-79 <br />4:13 P.M. <br />35 <br />9':7/8 <br />33.8 Average <br />24 <br />24 <br />l;i, 634 <br />MS 17 <br />9 <br />4,770 <br />19.4 <br />surface delays <br />The blasts were fired under the :,upe!-vision of Mr. <br />J.F. Reid. <br />n <br />