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WGR <br /> Southwest, Inc. <br /> 5.3 Drill Site Clearance <br /> Prior to field drilling operations, the proposed boring locations will be flagged and marked in <br /> white paint. Underground Service Alert (USA) will be contacted to identify any potential <br /> subsurface obstructions and/or conflicts. <br /> 5.4 Soil Borings <br /> Soil borings SB-1 through SB-5 will be advanced to a minimum total depth of 10 feet below <br /> ground surface(bgs). The soil borings will be advanced using dual-wall direct push technology. <br /> After sampling is completed, each boring will be backfilled using a Portland cement grout seal <br /> which will extend from the total depth explored to the ground surface. The grout will be <br /> pumped into the borings using a tremie hose. <br /> 5.5 Soil Sampling and Analysis <br /> Direct push technology will be used to collect soil samples at depths of 2, 5 and 10 feet bgs. The <br /> outer barrel for advancing the direct push soil borings will be approximately 2 inches in <br /> diameter, and the inner barrel will be approximately 1.75 inches in diameter. The dual-wall <br /> system minimizes sloughing, maintains boring alignment and minimizes vertical migration of <br /> contaminated soils or fluids. A closed barrel sampler will be advanced to the sampling depth, <br /> and the piston unlocked. The sampler, containing Macrocore®sample sleeves,will be driven to <br /> force soil into the sampler, and then the sampler will be removed and the sample sleeves <br /> extracted. Soil samples from the appropriate depth intervals will be selected and immediately <br /> sealed with Teflon®film and polyethylene caps. <br /> The soil samples will be labeled with all pertinent sampling information and packed on ice for <br /> subsequent delivery to a California state-certified laboratory for analyses. The soil in the <br /> remaining tubes will be screened for hydrocarbon vapors with a portable organic vapor analyzer <br /> (OVA), and described and logged by the field geologist in accordance with the Unified Soil <br /> Classification System (USCS). Sampling equipment will be decontaminated between sampling <br /> episodes using a triple rinse method consisting of a wash with Alconox® (or equivalent) <br /> solution, an initial rinse with tap water, and a final rinse with deionized water. Samples will be <br /> transported to a State of California certified laboratory under appropriate chain-of-custody <br /> documentation. <br /> 704. PRI.10 Page 6 March 16,2007 <br />