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ATTACHMENT A FIELD AND LABORATORY PROCEDURES Exploratory Drilling and Groundwater Monitoring Well Installation Ten Geoprobes® and three soil borings for exploratory soil and groundwater sampling and well installation were driven and drilled using direct push technology and 8-inch hollow stem auger drilling equipment, respectively to depths of approximately 38 feet bgs Borings were logged by a Pacific Environmental Group, Inc geologist using the Unified Soil Classification System and standard geological techniques Direct push soil samples for logging and analyticals were collected by continuous and discrete 5-foot depth interval sampling Hollow stem auger soil samples for logging and analyticals were collected at 5-foot depth intervals using a Calxforrua-modified split-spoon sampler The sampler was driven a maximum of I8 inches using a 140-pound hammer with a 30-inch drop All soil samples for chemical analysis were retained in brass liners, capped with Teflon squares and plastic end caps The samples were placed on ice for transport to the laboratory accompanied by chain-of-custody documentation All down-hole drilling and sampling equipment were steam-cleaned following the completion of the soil boring Down-hole sampling equipment were washed in a tri-sodium phosphate or alconox solution between samples The boreholes created by the Geoprobe® were backfilled with neat cement utilizing a tremae pipe from the bottom up to the surface No permanent structure remained in the boreholes The hollow stem auger borings were converted to a groundwater monitoring well by installing 2-inch diameter, flush-threaded, Schedule 40 PVC casing with 0 020-inch factory-slotted screen Approximately 20 feet of screen was placed in the bottom of the boring RMC #3 sand pack was placed in the annular space across the entire screened interval, and extended approximately 1 foot above the top of the screen for the well A 2 foot bentonite transition seal was placed atop the sand pack, and a Portland cement seal extended from the bentonite transition seal to the ground surface The Portland cement seal was emplaced by free fall from the surface in one continuous operation from the bottom of the interval and filled to the top The boring logs show lithology and well construction details The groundwater monitoring wells were developed after 24 hours of completion