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r� Harding Lawson Associatas <br /> III FIELD INVESTIGATION <br /> In December 1487, HLA initiated the Phase III investigation; a hollow-stem - <br /> t = auger drill rig was used to drill seven exploratory borings (P-1 through P-7) <br /> and three monitoring wells (MW-6 through MW-8). Their locations are shown on <br /> ..s Plate 1. The exploratory borings were drilled to collect soil and ground- <br /> water samples and check for free product. Two borinas P-1 and P-5, could not . <br /> x <br /> be advanced to ground water because utilities were encountered during drill- <br /> ing. Therefore soil and p p <br /> n9• ground-water samples were not collected from . -1 or <br /> P-5. - <br /> � a . Borings were advanced using 6-inch-diameter hollow-stem augers. Samples <br /> r were collected using a 2-1/2-inch inside diameter (I.D.) California modified <br /> ` split-barrel sampler lined with 6-inch-lono brass tubes. Drilling and excav- <br /> r <br /> ation were performed under the direction of an HLA field geologist, who logged <br /> and classified soils encountered. Soil samples were screened . <br /> : in the field <br /> - <br /> with a Gas Tech Model 1314 (calibrated to hexane), a device that measures the <br /> x presence of organic chemical vaoors. All soil samples were sealed at both <br /> ends with aluminum foil, plastic caps, and tape and stored in cooled ice <br /> chests. The logs of borings P-1 through P-7 and MW-6 and MW-7 are presented <br /> on Plates 3 through 7. The Soil Classification Chart is presented on P1ate:8. <br /> i <br /> a. <br /> y Prior to' oh-site use and between sampling intervals, all sampling equip- <br /> meet was thoroughly cleaned in a solution of Alconox and tap water,.._then <br /> I <br /> i . - - <br /> rinsed in tap water. Augers were steam-cleaned before drilling and between <br /> f <br />