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ALTON GEOSCIENCE <br />. GENERAL FIELD PROCEDURES FOR <br /> SOIL BOREHOLE DRILLING AND SAMPLING <br /> Soil borings and monitoring wells were drilled using 6- and <br /> 10-inch-diameter continuous-flight hollow-stem augers. To avoid <br /> cross-contamination, the augers were steam cleaned prior to <br /> drilling each boring. <br /> Soil samples were collected for soil description, field <br /> hydrocarbon vapor testing, and laboratory analysis. Samples were <br /> collected at 5-foot intervals beginning at 5 feet below grade <br /> (fbg) and at the capillary fringe. <br /> Soil samples were retrieved ahead of the lead auger using an <br /> 18-inch-long by 2-inch-diameter split-spoon sampler lined with <br /> 2-inch-diameter stainless steel or brass sample tube inserts. <br /> The sampler and sample tubes were washed with a phosphate-free <br /> Liquinox solution and rinsed before each sampling event. The <br /> sampler was driven by a 30-,inch free fall of a 140-pound hammer. <br /> Blow counts were recorded for three successive 6-inch intervals. <br /> Upon retrieval from the sampler, the sample tubes were removed <br /> and securely sealed with aluminum sheeting and polyurethane caps. <br /> The bottom sample tube was removed and capped. The sample was <br /> labeled with identification, depth, sampler's initials, and date <br /> of collection. The sample was kept on cubed, crushed, dry, or <br /> blue ice prior to and during transport to a California-certified <br /> laboratory. <br /> A geologist, hydrogeologist, or civil engineer described the soil <br /> samples using the Unified Soil Classification System, and <br /> included field estimates of density/consistency, moisture, color, <br /> grading, and soil type on the boring logs. The samples were <br /> transported following proper chain of custody procedures. <br /> i <br />