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• <br /> ATTACHMENT D <br /> FIELD AND LABORATORY PROCEDURES <br /> Exploratory Drilling and Soil Sampling <br /> The soil borings were drilled using 8-inch hollow-stem auger equipment Borings were <br /> logged by a SECOR scientist using the Unified Soil Classification System (USCS) and <br /> standard geologic techniques under the direction of a registered geologist Soil samples for <br /> logging were collected at 5-foot depth intervals using a California-modified split-spoon <br /> sampler The sampler was driven a maximum of 18 inches using a 140-pound hammer with <br /> a 30-inch drop Soil samples were collected by advancing 2-inch-diameter brass sample <br /> liners into undisturbed soil, reached through the center of the drill auger Soil samples for <br /> chemical analysis were retained in the brass liners, labeled, and capped with Teflon sheets <br /> and plastic end caps The samples were then sealed in zip-lock bags, placed on ice, and <br /> transported to the laboratory accompanied by the appropriate chain-of-custody <br /> documentation <br /> Down-hole drilling and sampling equipment was steam-cleaned prior to and following the <br /> completion of each soil boring Down-hole sampling equipment was washed in a tri-sodium <br /> phosphate or alconox solution between samples <br /> Groundwater Monitoring Well Installation and Development <br /> Each of the groundwater monitoring wells was constructed of 2-inch-diameter schedule 40 <br /> PVC blank casing and 0 020-inch-slot well screen with flush threads A #3-sand filter pack <br /> was installed in the annulus from the bottom of each borehole to approximately 2 feet above <br /> the top of the well screen, followed by a well seal consisting of a 3-foot-thick hydrated <br /> bentonite layer overlain by grout to the ground surface Each well was secured by a locking <br /> expandable well cap and fitted with a traffic-rated well box set in concrete The wells were <br /> developed by vigorously surging over the entire length of the screened interval, and purging <br /> approximately 10 casing volumes of water from each well or to dryness <br /> Soil Sampling for Stockpiled Soil <br /> Soil samples were collected by advancing 2-inch diameter brass sample liners into the soil <br /> stockpile, after removing approximately 6 inches to 1 foot of surface material in the sample <br />