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a r i • ATTACHMENT C FIELD AND LABORATORY PROCEDURES Exploratory Drilling and Soil Sampling The soil borings will be drilled using 8-inch hollow-stem auger drilling equipment to a depth of approximately 100 feet bgs The borings will be logged by a SECOR International Incorporated geologist or scientist under the direction of California Registered Geologist using the Unified Soil Classification System and standard geologic techniques Soil samples for logging will be collected at continuously using a California-modified split-spoon sampler The sampler will be driven a maximum of 18 inches using a 140-pound hammer with a 30-inch drop Soil samples for chemical analysis will be retained in brass liners, capped with Teflon squares and plastic end caps, and sealed in clean zip-lock bags Groundwater samples will be collected from the soil boring using a Simulprobe or similar sampling device The samples will be placed on ice for transport to the laboratory accompanied by chain-of-custody documentation Down-hole drilling and sampling equipment will be steam-cleaned prior to and following the completion of the soil borings Down-hole sampling equipment will be washed in a tri-sodium phosphate or alconox solution between samples The borings will be backfilled with cement grout from the bottom of the borings to the surface Groundwater Monitoring Well Installation Three borings will be converted to groundwater monitoring wells by installing 2-inch diameter, flush-threaded, Schedule 40 PVC casing with 0 020-inch factory-slotted screen Approximately 20 feet of screen will be placed in the bottom of the boring A grade of sand appropriate to the screen size will be placed in the annular space across the entire screened interval, and will extend approximately 2 feet above the top of the screen for the well A bentonite seal will extend three feet above the sand pack The monitoring well will be completed with neat cement from the bentonite seal to ground surface The well casing will be topped with a locking cap The well head will be contained in a watertight well box, either traffic rated and flush mounted or in a "stove- pipe" arrangement The boring logs will show well construction details The wells will be developed after completion The development procedure for each well will consist of pumping or bailing water from the well until the water is visibly clear, the well goes • dry, or until a maximum of ten casing volumes have been removed 077 43029 310/WPLAN Nov 2000 doe November 30,2000