ARCHIVED REPORTS_XR0012636 CASE 1

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_ :. . ..a s w.r ALTON GEOSCIENCE, INC. GENERAL FIELD PROCEDURES FOR SOIL BOREHOLE DRILLING AND SAHPLINO i. lin Exploratory borings will be drilled utilizing 8-inch.-diameter, continuous-flight, hollow-stem augers. The borings will be drilled near, or preferably downgradient of potential sources of contamination. To avoid cross--contamination, the augers will be steam-cleaned prior to drilling each borehole. it Sa pling_ rotgcol During drilling, samples will be collected at 5-foot intervals, beginning at 5 feet below grade and terminating at 30 feet below grade. The samples will be retrieved ahead of the lead auger, utilizing an 18-inch-long by 2-inch-diameter, Y split-spoon sampler lined with steam clean brass tuber. The _ sampler was driven by a 30-inch free fall of a 140-pound hammer. Blow counts will be recorded for three successive 6-inch. intervals. Before each sampling event, the sampler and sample tubes will be washed using a TriSodium Phosphate/water solution, and two tap water rinses. Upon retrieval, the bottom sample tube will be immediately removed from the sampler and securely sealed with Teflon sheeting and polyurethane caps, and wrapped with duct tape. s The sample will be labeled with the identification, sample depth, sampler's initials, and date of collection. The soil sample will be kept on dry or blue ice prior to and during transport to a state-certified laboratory. A staff or project level geologist, hydrogeologist, or civil engineer will describe the soil samples using the unified Soi? Classification System, and include field estimates of aensity/consistency, moisture, color, grading, and soil type on the boring logs. The boring logs will be reviewed and stamped by geologist or civil engineer, who is registered and/or certified in the State of California.