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Ms. Anne Connor March 9, 2007 Page 4 approximately 8 feet bgs. This deeper material also was discolored and smelled of petroleum hydrocarbons and produced elevated readings on the PID. Following excavation of the test pit, approximately 40 cubic yards of material had been removed and placed into the bins. The hardpan layer noted during previous investigations was found to be discontinuous across the excavation area. Where present, it consisted of a layer of calcified soils approximately 6 inches thick. Soils beneath the hardpan consisted of sand and sandy silt. Following excavation activities, SECOR collected soil samples for chemical analysis. Soil v samples were collected from the backhoe bucket using laboratory-supplied glass jars, labeled, and placed into a cooler containing ice for storage. SECOR collected soil samples from the north and east sidewalls at a depth of approximately 3 feet bgs (sample IDs NW1- 3' and EW1-3', respectively), and from depths of 6 and 8 feet bgs in the `test pit' excavation (sample IDs TP-6' and TP-8', respectively). Soil samples were delivered to Severn Trent Laboratories, Inc. (STL), a state-certified analytical laboratory located in Pleasanton, California. The soil samples were analyzed for total petroleum hydrocarbons as gasoline (TPHg) and benzene, toluene, ethylbenzene, and W total xylenes (BTEX) by U.S. Environmental Protection Agency (EPA) Method 826013, and for total petroleum hydrocarbons as diesel (TPHd) and motor oil (TPHmo) by modified EPA Method 8015M with silica gel cleanup. Laboratory analytical results are summarized on Table 1 'and the laboratory report is attached. Backfill and Compaction U On February 16, 2007, ERRG and SECOR staff returned to the Site to backfill the excavation. Backfill and compaction equipment used by ERRG consisted of a loader/backhoe equipped with a compaction wheel, and a walk-behind pneumatic compactor (Jumping Jack-style). While at the Site, ERRG and SECOR took delivery of approximately 50 tons of class 2 aggregate base from Teichert Aggregates in Tracy, California. Prior to backfilling, the excavation was prepared by using the compaction wheel to smooth and compact the native soils in the bottom of the excavation, and a layer of orange snow fencing was installed to differentiate imported soils from native during future work, if necessary. The imported fill was introduced into the excavation in 1-foot lifts, and each lift was compacted to an estimated 90 percent relative compaction. The entire imported fill U I:\PG&E\French Camp\2007 Investigation\report\Excavation Report_Final.doc March 9,2007 Project No.050T.50351.00.0003 LJ