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— = _ <br /> r� <br /> APPENDIX A <br /> INVES17GATIVE PROCEDURES <br /> Emploratory Soil Boring and Monitoring Well Installation <br /> The soil borings were drilled using hollow-stem auger drilling equipment. The borings <br /> were logged by a PACIFIC geologist using the Unified Soil Clas2ification System and <br /> standard geologic techniques. Soil samples for logging and ciemical analysis were <br /> collected at depth intervals of 5 feet by advancing a California modiL-d 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-inch <br /> drop. Soil samples for chemical analysis were retained in the brass liners and capped <br /> with aluminum foil and plastic end caps, and sealed in clean glass jars. The samples <br /> were placed on ice and transported to the laboratory accompanied by the appropriate <br /> chain-of-custudy documentation. The drilling equipment was steam-cleaned between <br /> each boring. <br /> The borings were converted to group}water monitoring wells with the installation of <br /> 3=;'.lith diameter flush-threaded Sc'-cdule 40 PVC casing and 0.020-inch factory-slotted <br /> . <br /> screen. Graded sand pack was"placed in the annular space a&oss the,screened interval.— <br /> t and,extends approximately le s <br /> _foot,above thcreened secttans: A bentonite anti <br /> concrete seal was placed from the top of the sand pack to the ground surface. A locking <br /> cap and protective vault box were installed on the top of each well. Following well <br /> completion,well eleva-dom were surveyed to the nearest 0.01 foot relative to mean sea <br /> level datum by a licensed surveyor. <br /> Organic Vapor Analysis <br /> Soil samples collected during drilling vrere analyzed in the field for ionizable organic <br /> compounds using the i*`NU Model PI-101 photo-ionization detector with a 10.2 eV <br /> lamp. The test procedure involves measuring approximately 30 grams from an undis- <br /> turbed soil sample,placing this sub-sample in a clean glass jar, and sealing the jar with <br /> aluminum foil secured under a ring-type threaded lid. The jar is warmed for approxi- <br /> mately 20 minutes, then the foil is pierced and the head-space within the jar is tested for <br /> 310010/REPORT A- 1 <br /> Febraary 13,1991 <br />