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r' <br /> ATTACHMENT A <br /> FIELD AND LABORATORY PROCEDURES <br /> Exploratory Drilling <br /> The soil borings were drilled using 8-inch hollow-stem auger drilling equipment. Borings <br /> were logged by an IT engineer using the Unified Soil Classification System and standard <br /> geologic techniques. Soil samples were collected at 5-foot depth intervals using a California- <br /> modified split-spoon sampler. The sampler was driven a maximum of 18 inches using a <br /> 140-pound hammer with a 30-inch drop. All soil samples for chemical analysis were retained <br /> in brass liners, capped with Teflon squares and plastic end caps, and sealed in ZiplockTm-style <br /> bags. The samples were placed on ice for transport to the laboratory accompanied by chain- <br /> of-custody documentation. All down-hole drilling and sampling equipment was steam- <br /> cleaned following the completion of the soil boring. Down-hole sampling equipment was <br /> washed in a trisodium phosphate or alconox solution between samples. <br /> Groundwater Monitoring Well installation <br /> Groundwater monitoring wells were completed in four soil borings by installing 2-inch <br /> diameter, flush-threaded, Schedule 40 PVC casing with 0.020-inch factory-slotted screen. <br /> Approximately 20 feet of screen was placed in the bottom of the boring. An RMC 2112 sand <br /> pack, was placed in the annular space across the entire screened interval, and extended <br /> approximately 2 feet above the top of the screen. A 2-foot bentonite transition seal was <br /> placed atop the sand pack, and a Portland cement seal extends from the bentonite transition <br /> seal to the ground surface. The Portland cement seal was emplaced by tremie pipe or through <br /> the center of the hollow-stem augers in one continuous operation. The boring logs show well <br /> construction details. <br /> The groundwater monitoring wells were developed after completion. The development <br /> procedure for each well consisted of pumping or bailing water from the well until the water is <br /> visibly clear, the well goes dry, or until a maximum of ten casing volumes have been <br /> removed. <br /> 911-011.1 B/Report A-1 <br />