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• <br /> ATTACHMENT A <br /> FIELD AND LABORATORY PROCEDURES <br /> Monitoring Well Installation Procedures <br /> The borings for Monitoring Wells MW-8 and MW-9 were drilled using 8-inch <br /> diameter hollow-stem auger drilling equipment All borings were logged by a <br /> Pacific Environmental Group, Inc. geologist using the Unified Soil Classification <br /> System and standard geologic techniques The boring logs are presented in this <br /> attachment Soil samples for logging and chemical analyses were collected at <br /> minimum 5-foot depth intervals by advancing a California-modified split-spoon <br /> sampler with brass liners into undisturbed soil beyond the tip of the auger. The <br /> sampler was driven a maximum of 18 inches using a 140-pound hammer with a <br /> 30-mch drop. Soil samples for chemical analysts were retained in brass liners, <br /> capped with Teflon and plastic end caps, and sealed in zip-lock plastic bags. These <br /> samples were placed on ice for transport to the laboratory accompanied by chain- <br /> of-custody documentation (Attachment B). All down-hole drilling equipment was <br /> steam-cleaned between boring locations The borings were converted to <br /> groundwater monitoring wells by the installation of 2-inch diameter Schedule 40 <br /> PVC casing and 0 020-inch factory-slotted screen. <br /> Groundwater was encountered in Monitoring Wells MW-8 and MW-9 at a depth <br /> of 43 feet bgs The wells were installed for the purpose of groundwater <br /> monitoring. A graded 2 x 12 Lonestar sand pack was placed in the annular space <br /> across the screened depth interval, and extends approximately 1 feet above the top <br /> of the screens. A bentonite and cement seal extends from the sand pack to the <br /> ground surface A watertight locking cap and protective vault box were installed <br /> on top of each well. The attached boring logs show well construction details. <br /> Organic Vapor Procedures <br /> Soil samples collected during drilling were analyzed in the field for volatile organic <br /> compounds using the HNU Model PI 101 photo-ionization detector (PID) with a <br /> 10.2 eV lamp. The test procedure involved measuring approximately 30 grams <br /> • <br /> 31004002/MWINSTAL A- 1 October 4, 1994 <br />