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J <br /> _ APPENDIX A <br /> GENERAL FIELD PROCEDURES, BORING LOGS, <br /> AND WELL CONSTRUCTION DETAILS <br /> A description of general field procedures to be utilized <br /> during the proposed investigation is presented below. <br /> A. 1 Drilling and Soil Sampling <br /> Soil borings are to be drilled using 10-inch-diameter, <br /> continuous-flight hollow-stem augers. The first 4 feet of <br /> each boring will be hand excavated to avoid damage to <br /> subsurface structures. To avoid cross-contamination, the <br /> augers will be steam-cleaned prior to drilling each soil <br /> boring. <br /> Soil samples will be obtained from each boring for soil - <br /> description, field hydrocarbon vapor testing, and laboratory <br /> analysis. Soil samples will be retrieved ahead of the lead <br /> auger utilizing an 18-inch-long by 2 .5-inch-diameter, split- <br /> spoon sampler lined with 2-inch-diameter, brass sample <br /> inserts. The sampler and sample tubes will be washed with a <br /> Alcanox (laboratory grade) solution and rinsed with tap water <br />. before each sample is collected. The sampler will be driven <br /> by a 30-inch free fail of a 1.40-pound hammer. Blow counts <br /> will be recorded for three successive 6-inch intervals. One <br /> monitoring well will be continuously sampled. If rock or <br /> impervious material is encountered during drilling, the boring <br /> will be terminated at that depth or a maximum depth of 50 <br /> feet. <br /> Soil samples will be collected from borings at 5-foot <br /> intervals and at significant stratigraphic changes to the <br /> total depth of the boring. If ground water is present, soil <br /> samples will also be collected from the capillary fringe just <br /> above the water table. For borings drilled within a tank <br /> cavity backfill, a soil sample will be obtained from the <br /> native material approximately one foot below the base of the <br /> backfill. Samples collected below the water table will not be <br /> submitted for laboratory analysis. <br /> During sampling the bottom sample insert will be removed <br /> immediately from the sampler and securely covered with Teflon <br /> or aluminum sheeting and capped with polyurethane caps for <br /> possible laboratory analysis. The sample will be labeled with <br /> a sample identification number, sample depth, <br /> geologist's/engineer's initials, and date of collection. The <br /> soil samples will be kept on ice prior to and during transport <br />• to a California-certified laboratory. <br />