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Geological Technics Inc. *..W %../ Page 2 Geologic Report for CFM Plant Project 394.3 November 28,1995 y On October 24-26, 1995 confirmation soil samples from various depths were collected and handled by Tri-Valley Growers personnel under the supervision of Mr. Tim McDonald, professional geologist, of Geological Technics Inc. Soil samples were recovered in precleaned discrete liners, sealed with aluminum foil, capped, sealed with duct tape, labeled, inserted into a plastic zip lock bag, and then placed in a cooler containing crushed ice for transport to the laboratory. A chain of custody was filled out listing all samples collected and identifying persons charged with their custody. Description of Soils Encountered During Drilling The shallow geologic soils encountered at this site are typical for the area comprising of alluvial sediments sourced from the Sierra Mountain Range to the east. The following is a brief summary of the sediments encountered: From the surface to approximately 17 feet is a pea gravel excavation backfill material presumably emplaced after the tank removal and overexcavation. Beneath this backfill are native sediments consisting of a clayey sand/sandy clay to approximately 18 feet. A silty very fine to fine sand/sandy silt containing varying amounts of a plastic clay matrix was observed to extend to 36.1 feet below grade (deepest sediments encountered). Formation moisture ranged from dry to moist. Remedial Excavation Activity The following are a summary of observations and documentation of the supervised sampling activity: October 24, 1995 The first boring was advanced using a 3 foot diameter bit to a total depth of 28 feet below grade at the northwest corner of the tank removal excavation. A 4 foot diameter conductor casing was used to prevent the peagravel backfill from sloughing into the remedial boring. Confirmation soil samples were collected at 18 and 28 feet below grade. No OVM readings above background were observed from soil screened from this boring. A second boring was started just southeast of the first boring. The auger bit wandered into the first boring which caused excessive sloughing. It was decided that the entire excavation would be stabilized using a control density backfill and that the drilling operations would resume the next day. October 25, 1995 The second boring was advanced using a 6 foot diameter bit to a total depth of 36.1 feet below grade at the east side of the tank removal excavation. Collection of confirmation soil samples was attempted at 16 feet using a 2.5" drive sampler. Difficulty was experienced using this sampler due to its tendency to skid down the