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f z <br /> 1 <br />;t r <br /> i <br /> � 1 <br /> I1' IRS APPENDIX A <br /> INVESTIGATIVE PROCEDURES }} <br /> Exploratory Soil Boring;and Monitoring Well Installation <br /> The soil borings were drilled using hollow-stem auger drilling equipment,and togged by E <br /> ! a PACIFIC geologist using the Unified Soil Classification System and standard geologic <br /> E techniques. Soil samples for logging and chemical analysis were collected at a t <br /> L� maximum depth interval of 7-1/2 feet by advancing a California modified split-spoon <br /> sampler with brass sample 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 30-ins" <br /> drop. Soil samples for chemical analysis were retained in the brass liners, capped with <br /> aluminum foil and plastic end caps, and sealed in clean glass jars. The samples were <br /> placed on ice and transported to the laboratory accompanied by the appropriate chain- 1 <br /> { of-custody documentation.. The drilling equipment was steam-cleaned after each <br /> boring. <br /> _ Selected borings were converted to groundwater monitoring wells by the installation of i. <br /> 3-inch diameter flush-threaded Schedule 40 PVC casing with 0.020-inch factory-slotted <br /> ! screen. Graded 12x20 sand pack was placed in the annular space across the screened j <br /> interval, and the wells were surge-blocked to remove void spaces in the sand pack. A <br /> t bentonite and concrete seal was.placed from the top of the sand pack to the ground <br /> surface. A locking cap and protective vault box were installed on the top of each well. <br /> k Well elevations were surveyed by a licensed surveyor to an accuracy of 0.01 foot, <br /> Lr relative to the USGS mean sea level datum. <br /> Organic Vapor Analysis €{ <br /> t Soil samples collected during drilling were analyzed in the field for ionizable organic <br /> compounds using the HNU Model PI-101 photo-ionization detector with a 10.2 eV. <br /> lamp. The test procedure involves measuring approximately 30 grams from an - <br /> undisturbed soil sample, placing this sub-sample in a clean glass jar, and sealing the jar <br /> i A with aluminum foil secured under a ring-type threaded lid. The jar is warmed for i <br /> approximately 20 minutes, then the foil is pierced and the head-space within the jar is ! <br /> 310010/REPORT:' A- 1 September 30,1991 , <br /> i s <br /> r 1 <br />