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Geological Technics Inc. %--W %-010 Page 3 Geologic Report for CFM Plant Project 394.3 November 28,1995 side wall and to come into contact with slough at the bottom of the excavation. Sampler position control was difficult because of the excessive length of the sectional drive rod. Therefore it was decided to use a narrow diameter core sampler driven using an electrically actuated percussion hammer. Discrete confirmation soil samples were successfully collected from the south, east and north side walls at 16 feet. No OVM readings above background were observed from soil screened from these samples. However it should be noted that the narrow diameter core sampler would only collect a limited volume of soil and thus allowed only minimal volumes to be field screened. The remedial boring continued down to the planned depth of 28 feet. Due to safety and sample integrity concerns it was decided on consultation with Ms. Margaret Lagorio of the SJCPHS that confirmation samples would be collected off of the leading edge of the auger bit. The auger teeth were first scraped clean of any residual dirt and then advanced. The auger was carefully lifted and a sample was collected for field screening and laboratory analyses off of the bit. The OVM registered elevated readings at 28 feet. It was not known if these reading were representative of the bottom hole soil or if they were partly made up of slough from up above. Therefore it was decided to continue drilling downward collecting field screening samples at two foot intervals. A final bottom hole sample for laboratory analyses was collected off of the auger bit from 36.1 feet below grade under the direction of Ms. Margaret Lagorio of the SJCPHS. The east boring was backfilled that afternoon using a control density fill. October 26, 1995 The third boring was advanced using a 6 foot diameter bit to a total depth of 36 feet below grade at the west side of the tank removal excavation. Confirmation soil samples were successfully collected from the south and north side walls at 16 feet using the narrow diameter core sampler. The west wall sample was collected on October 23, 1995 during the first boring. No OVM readings above background were observed from soil screened from this boring. The remedial boring was advanced to the planned depth of 28 feet and then continued to 36 feet total depth to be consistent with the east boring. A final bottom hole sample was collected off of the auger bit from 36 feet below grade. The west boring was backfilled that afternoon using a control density fill.