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t <br /> <br />PARAGON <br />CONSULTING GROUP <br />i ~ i ~ <br />Permit #: /J7 i~~ -~/ G Confidental?: <br />Class: a~«r„--ls Type-Seq.: <br />From: ~ra~ ,.~ To:~ <br />Doc. Name: /~Jov~i~~x rt~~.~ iivsP/_l <br />Doc. Date (if no date stamp <br />SENT VIA CERTIFIED MAIL <br />Certified Number 7001 1940 0006 058I 4341 <br />May 1, 2002 <br />1103 O+4 rYh Drivq Surze 110 <br />Port cdurc, co eoszs <br />rlwrc f970) 377-I6W <br />Fu (9701377~IB80 <br />vww.q,sgumgmm <br />RECE~oIED <br />Dnwo M. Rau, P.E., DEE <br />Scort A Rurxuwno, P.E <br />Baas Surm, P.E <br />Jnwss M. Txows, P.E <br />BRno C. woHUx <br />Stever A Mnu~ P.E. <br />n.ir D. w~~, Er.r. <br />IIFAl11FA S. NnmwnN - <br />Ms. Kate Pickford MAY 0 & 2002 <br />Colorado Division of Minerals and Geology <br />1313 Sherman Street, Room 215 Division of Minerals and Geology <br />Denver, Colorado 80203 <br />RE: April 2002 Quarterly Monitoring Report/Request for Site Closure <br />Aggregate Industries F Street Facility <br />4509 F Street <br />Greeley, Colorado <br />Project Number 1001018 <br />Dear Ms. Pickford: <br />Enclosed are two (2) copies of the April 2002 Quarterly Monitoring Report for the above- <br />referenced site. Petroleum hydrocarbon concentrations were not observed above the <br />laboratory detection limits or wece observed at relatively low concentrations in groundwater <br />samples collected from the site in April 2002. The April 2002 sampling episode was the <br />fourth event in which benzene-toluene-ethylbenzene-xylenes concentrations were not <br />observed above the Maximum Contaminant Levels in groundwater samples collected from <br />the site. Therefore, it is our opinion that additional monitoring, assessment or abatement is <br />not warranted at the site at this time and site closure should be granted by the Colorado <br />Division of Minerals and Geology for the 2001 diesel-fuel release. <br />As summarized in previous reports, the volume of the diesel-fuel spill was estimated to be <br />approximately 10,840 gallons based on information provided by Aggregate Industries. We <br />attempted to perform a mass balance to compare the amount of diesel fuel released versus <br />the amount of diesel fuel recovered during the soil and groundwater abatement activities. <br />Due to the limited number of impacted samples analyzed from the site, the mass balance <br />indicated that much more diesel fuel was recovered than released. Based on experience and <br />professional judgement, a release of 10,840 gallons would be expected to cause greater <br />impacts than have been observed at the site. The apparent lack of significant impacts <br />appears to indicate that the abatement activities were highly successful in cleaning up the <br />spill or that the spill amount was much lower than estimated by Aggregate Industries. <br />Possible explanations for an erroneous spill estimate could be fuel theft or short fuel <br />deliveries. <br />ENVIRONMENTAL ENGINEERING nND GEOHYDROLOGY <br />