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Page 2 Boring, Well Installation and Survey The boring was installed on the property on September 6, 1991 The boring was drilled by Aqua Science Engineers of San Ramon, California, using a B-53 truck- mounted drill rig equipped with 8-inch-diameter hollow-stem augers to a depth of 38 feet, southwest of the former underground fuel storage tank location. The boring was lithologically logged by a California-registered geologist (see Figure 2 -Boring Log). Groundwater was encountered at approximately 29 feet BGS Cuttings from the auger were placed in steel 55 gallon drums, which were sealed and left in the fenced dumpster area No odor was noted from the auger cuttings. The boring was converted to a monitoring well by installing 2-inch diameter flush- threaded, Schedule 40 PVC well casing to a depth of 37 feet BGS. The 0.010 inch screened interval is the bottom 20 feet. The coarse sand pack was placed down the well by pouring the sand down the annulus between the well screen and inside of the hollow-stem auger, extending the top of the sand pack 2 feet above the screened interval. An approximately 2-foot-thick layer of bentonite pellets was placed above the filter pack and hydrated with tap water. The remaining annular space was back filled with a cement/bentonite grout which filled the remaining annulus to within 6" of the surface. The well top was covered with a cemented-in well box and finished at grade The well casings were surveyed by a licensed surveyor to determine well elevations and tie in the new well (MW 4) with the existing wells. Elevations were shot from a municipal benchmark along North Main Street to tie the wells in to the existing surface elevations All four wells were marked with a permanent marker on the well casing to provide a consistent reference point when measuring groundwater elevations. The land survey results are in the Appendix. Sample Collection (Soil) Soil samples were collected every five feet for lithologic, hydrogeologic and chemical analyses Samples were obtained with a modified California split barrel sampler Three six inch brass tubes were driven into the soil with a 140 pound drop hammer falling 30 inches. The split-barrel sampler was extracted from the boring The middle sample tube was saved for chemical analysis, and was covered on the ends with teflon tape and plastic caps, and placed in zip lock plastic bags The samples were labeled and placed on ice for transport to the State certified analytical laboratory. Chain of Custody forms accompanied the samples to the laboratory (Appendix ) Soil samples were inspected for lithologic classification in accordance with the Unified Soil Classification System (USCS). A copy of the USCS is in the Appendix Parker Environmental Servlce5 4185 Rialto Court Pittsburg CA 94565-6116 Phone (510) 439-1024 Fax (510) 439-2566