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excavation were sampled and analyzed by the TLC method When the west excavation reached 18 feet bgs the TLC results indicated that soils on the walls and the floor of the excavation were below 10,000 mg/kg Confirmatory samples were obtained from all four stdewalls and three samples from the floor of the excavation were submitted to a DHS certified laboratory for TPH/D analysts. The analytical results of these samples are presented to Figure 4 4 ' As indicated in Figure 4 4, one of the soil samples from the floor of the west excavation, exceeded 10,000 mg/kg TPH/D After these results were received, additional soil was removed from the floor of the west excavation and the floor sample was resampled in approximately the same location The additional soil removal achieved the remedial objective, and the west excavation was terminated at 22 feet bgs The excavation at the east end of the former maintenance building proceeded to the same fashion as the west excavation screening tests were performed as the excavation progressed, and the soil was either stockpiled or taken directly to the treatment cell Initial soil samples from the sides and bottom the east excavation were obtained when the depth of the pit was 20 feet Following receipt of the laboratory test results, an additional six feet of soil was removed from the pit and the bottom of the pit was resampled The total depth of the east excavation at completion was 26 feet below grade The results of the analytical tests are presented to Appendix, / In addition to the excavated soil, 88 drums of soil cuttings from previous site investigations we a emptied onto the biotreatment cell The empty drums were transported off-site for recycling . SA total of approximately 2,800 to 3,000 cubic yards of soil was removed from the two excavations Approximately 1,600 cubic yards contained TLC-TPH/D values greater than 10,000 mg/kg and was transported directly to the biotreatment cell The remaining 1,200 cubic yards was primarily from the stockpile identified as 0132 (Figure 4 4) was analyzed and found to be impacted, and was also ' transported into the biotreatment cell All but 150 cubic yards of soil from OBC with certified laboratory TPH/D analytical results less than 100 mg/kg (Figure 4 4) was also placed in the biotreatment cell 4 2 3 Backfill and Capping tThe east and west excavation pits were backfilled with approximately 2,600 cubic yards of clean imported fill, and 150 cubic yards with TPH/D concentrations less than 100 mg/kg The imported fill ' is a silty sand obtained from a local quarry Following completion of compaction curve tests conducted by a certified geotechnical engineer (Applied Inspection Management, of Modesto, California) the imported soil was placed in the pits and compacted by jetting The compacted fill was tested for density rto verify that 95% relative compaction was achieved The upper seven feet of the west excavation was SAC36 046 17 r