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SOBIE AND ASSOCIATES, INC. <br /> PAGE 5 <br /> Paulson And Sons Inc . January 26 , 1993 <br /> Attention: Mr. Bill Paulson Re : Bill Paulson Quarry Blasting <br /> At the present time , a client of ours operates a quarry in the <br /> City of Rockford, Illinois . The quarry operation excavation has <br /> developed along a line which parallels an existing in service <br /> buried pipeline . The quarry bench is about 50 feet in height ; <br /> the operational width is in excess of 1200 feet, which closely <br /> parallels the pipeline . The blasting operations have consist- <br /> ently approached separation distances of about 50 feet from the <br /> pipeline . This quarry has been in regular operation for over <br /> 23 years and represents an example of quarry blasting being <br /> conducted in relatively close proximity to a pipeline . <br /> In our opinion, as related to pipeline integrity, a PPV of 2 . 0 <br /> inches per second, would represent a very conservative and SAFE <br /> vibration limit. It should also be recognized that seismographic <br /> tests conducted to monitor blast vibrations at the pipeline <br /> could also be useful in documenting conformance to applicable <br /> requirements in ILHR7 , in addition to providing vibration data <br /> useful in determining ground vibration intensity at other local <br /> structures which may be of interest . In our opinion, limiting <br /> the PPV at the South property line to 2 . 0 inches per second would . <br /> completely insure the safety and structural integrity of both <br /> the City water tower and the City' s new drilled water well which <br /> are located in excess of 2500 feet from the south property line . <br /> RECOMMENDATIONS <br /> All blasting operations should conform to all Local , State , and Federal <br /> regulations regarding explosive use . A limiting peak particle velocity of <br /> ground motion of 2 . 0 inches per second should be established at the KPI <br /> pipeline location. The peak velocity of ground motion should be determined <br /> by a seismographic test of each blast , until such time as enough test data <br /> is obtained so that all interested parties can be assured that non-monitored <br /> blasts will not result in excessive ground vibration at the pipeline . <br /> The results of the seismographic tests should be made available to KPI , and <br /> other interested parties , on a regular basis . If we may be of further <br /> assistance to you at this time please contact this office . <br /> Yours truly, <br /> SOBIE AND ASSOCIATES INC. <br /> 0/6. -A-.4oi <br /> Milton A. Sobie <br /> R.P.E. , Ill 23546 <br /> SAS/c <br /> SAS 92603 <br /> fax <br />