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Because the proposed SVE/GW co-extraction wells are to be installed adjacent to (within approximately 10 feet) corresponding monitoring wells which have been previously logged and sampled, soil samples will be collected at the discretion of the on-site geologist. At least one soil sample will be collected from each well from the interval between 15 and 20 feet for field examination (and possible laboratory analyses)to further assess the viability of SVE from the soil at this horizon. The objective of this effort is to install the best possible SVE/Groundwater co-extraction well as cost effectively as possible. In addition to the provisions cited above: • The borehole for each well will be drilled by a drilling company with a current State Water Well Drillers License (C57). The drill rig will utilize 12-inch-diameter hollow- stem augers. • Well construction will be permitted and inspected by the San Joaquin County Environmental Health Division. • The slot size based upon record of previous field examinations will be 0.020 in. • The annular space around each well casing will be packed with clean graded sand (from the bottom to 2 feet above the perforated casing). • Each well surface seal will be constructed with a minimum of 1 bucket of bentonite pellets above the sand pack(approx 1 foot), followed by cement grout to the surface. The minimum seal length will be five feet (except at proposed extraction well EW-1 where the seal will extend from a depth of approximately 5 ft. below ground surface to the bottom of the concrete well vault). • The well heads will be secured with a water-tight, well cap designed to extract both soil vapor and groundwater. • Each monitoring well will be developed to stabilize the sand filter and clear the well of fine material. The wells will be bailed and surged using a stainless steel bailer until four to ten well volumes have been removed and temperature, pH, and conductivity have stabilized. • Groundwater produced during well development and equipment rinse water will be contained in 55-gallon steel drums. The drums will be properly labeled to help ensure appropriate disposal. • Soil produced during drilling will be placed on plastic sheeting, covered with plastic sheeting, and retained on the site until laboratory analyses is available to determine its appropriate disposal. Ronald W. Michelson k.G. (CA#3875) No. 3379, 1 ,