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C,eological recknics Inc. Page 2 Del Valle(Hwy 99) Project No.: 1117.2 January 20,2004 2.1 Tank Location Search GTI researched the EHD and County Accessor files to determine the actual site of the former UST. Included in these files were Aerial photos, Tentative Subdivision Map of Little John Creek, and previous facility maps. The location of the former tank has been plotted on Figure 3A & 313 — Sample Points for this work plan. Using wooden stakes, the location of the boreholes were marked on the ground. Unfortunately, the eastern sample point was plotted on top of some newly installed underground utility lines for the development project being installed on this property. Therefore, we only installed one of the boreholes, the westerly borehole as shown on the map. 2.2 Borehole Drilling& Soil Sample Collection On December 30, 2003, GTI and V&W Drilling mobilized to the site to perform the drilling as planned. However, due to the heavy rains in December, the drill site was to wet and muddy to allow drill rig access. So we planned to reschedule the work once the soil had dried out enough. On January 14, 2004, the soil was sufficiently dry to perform the fieldwork. One borehole was drilled in the area described above as the location of the former UST. This borehole was drilled using a GeoProbe rig owned and operated by V&W Drilling of Isleton, CA (C57# 720904). The GeoProbe advances a coring tool with a pneumatic hammer. We operated the equipment in a continuous core mode. As the core tool advances, the soil sample enters an acetate cylinder contained in the coring tool. Upon filling, the coring tool is pulled from the hole and the cylinder is removed. The cylinder is then cut and the selected interval is capped with plastic end caps and placed on ice for shipment to the laboratory. The remainder is used for geologic logging. A boring log providing sediment description using the USCS and other field observations as described below was prepared by a professional geologist working under the supervision of a registered geologist. The log is attached in Appendix B. Since selected soil samples collected were submitted for laboratory analysis, a screening process was used to gather additional information through field observation. These observations will include: • Sediment type, especially grain size and clay content • Moisture content • Visible evidence of contamination, i.e., color change due to reduction of iron or discoloration from hydrocarbons and other pollutants 2.3 Soil Laboratory Analyses A total of four soil samples were submitted to CLS for the following analysis: Oxygenates (5)by EPA method 8260 The depths of these samples are: 14, 17, 20, and 23 feet bgs.