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15 June 2009 - AGE-NC Project No.05-1306 Page 13 of 33 from surface grade to 5 feet bgs). Soil field screened as non-impacted was eventually confirmed to be free of petroleum hydrocarbon impacts through composite laboratoryanal analysis. Ground water was initially encountered at 14 feet bgs in the southeast corner of the over-excavation and eventuallystabilized atapproximately - 25 feet. The saturated loll created a thick, but semi -- viscous slurry of sediment and water. The over-excavation reached depths below 28 feet bgs in center and eastern section of the pit while attempting to create a sump to facilitate dewatering activities. Approximately,963 cubic yards ofpetr6leumhydrocarbon-impacted sail(approximately 35 percent more soil than proposed) and 240 cubic yards of clean soil were excavated from the site. Figure 2 illustrates the approximate location and lateral extent of the over-excavation. 5.2.2. Over-excavation Backfilling On 23 through 28 September 2005,the over-excavation was backfilled using a combination of pea gravel,clean native soil removed from the over-excavation and imported A/B baserock.The volume of clean overburden returned to the over-excavation as backfill was approximately 240 cubic yards. The over-excavation was compacted by Valued Engineering using a 66-inch Riding Thumbwheel Compactor in 5-foot lifts from the floor of the over-excavation to 10 feet bgs and in I-foot lifts from 10 feet bgs to the surface grade. 5.2.3. Disposal of Hydrocarbon-Imp acted Soil p Y p _ l On 21 through 26 September 2005, approximately 1,308 tons of petroleum hydrocarbon-impacted soil was transported to Forward Landfill a licensed Class II waste disposal facility in Manteca, California for disposal. 5.3. GROUND WATER DEWATERING (EXTRACTION) AGE originally planned to extract, treat and discharge ground water from the over-excavation pit to permitted publicly owned treatment works, however, the thick slurry conditions previously discussed caused continuous pump malfunctions.Approximately 1,000 gallons of ground water was extracted,placed in a holding tank,removed by vacuum truck and properly disposed of to a Class H disposal facility.No ground water was discharged. i Advanced GeoEnvironmental,Inc.