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• <br /> BOREHOLE DRILLING <br /> EVAX will retain Spectrum Exploration, Inc. (Spectrum; License 512268 <br /> C57) of Stockton, California to install the groundwater monitoring <br /> wells. The boring for each well will be drilled with a truck mounted <br /> drill rig equipped with continuous flight, hollow stem augers of 9-inch <br /> outside diameter. The augers and other drill parts will be steam <br /> cleaned between borings to minimize the possibility of cross-hole <br /> contamination. EVAX will use a hand operated auger to test for <br /> underground utility lines and piping in the areas to be drilled. <br /> Drilling and well construction will be supervised by a California <br /> Registered Geologist for EVAX. The boring will be advanced to a depth <br /> of approximately 22 feet for each well . Each boring will be oriented <br /> vertical to the ground surface and have a diameter of approximately 9 <br /> inches. The proposed well locations are presented in the Site Plan, <br /> Figure 1. One of the wells will be installed within 10 feet and in the <br /> inferred downgradient direction of the former USTs. <br /> SOIL SAMPLING <br /> . Soil samples will be taken at approximately 5 foot intervals and/or at <br /> significant lithological transitions. Samples will be taken using a <br /> California modified, split-spoon sampler loaded with three steam <br /> cleaned, brass sleeves each of 2-inch diameter and 6-inch length. <br /> Sampling will involve advancing the boring to a point dust above the <br /> sampling depth, sliding the sampler with brass sleeves through the <br /> hollow stem of augers, and then driving the sampler 18 inches into the <br /> relatively undisturbed soils with a standard 140-pound hammer dropped <br /> repeatedly 30 inches. <br /> Soil samples will be described following the Unified Soil <br /> Classification System and field screened with a portable organic vapor <br /> analyzer. EVAX anticipates that one soil-packed sleeve from each <br /> sampling interval will be sealed with aluminum foil , plastic caps, and <br /> tape; and then labeled and placed on ice storage. Selected soil <br /> samples will be submitted to a state-certified laboratory and analyzed <br /> for gasoline hydrocarbon products. Chain of custody protocol will be <br /> initiated in the field and followed throughout the handling of soil <br /> samples. Geological and other field data will be summarized in the <br /> logs of borings. <br /> • <br />