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1 <br /> Ms Mary Meays Page 5 <br /> March 2, 1994 <br /> was initially used to establish the required extent of the excavation In <br /> addition, the excavation was monitored with a direct-reading instrument <br /> (FID) to detect the presence of gasoline vapors When affected soils were no <br /> longer indicated by visual evidence or the FID, confirmation soil samples <br /> were collected and analyzed by the mobile laboratory If the sample analysis <br /> results indicated that the cleanup goal of 100 ppm TPHg and 1 ppm total BTEX <br /> had not been met, excavation activities continued This procedure was <br /> repeated until all affected soils had been excavated and soil cleanup goals <br /> were achieved "OV' t )r�fi !� Pre t E �5 6C7Y�d'L fii-0/\--> �✓e v4CJ <br /> -Qv-rKa-A e KCci v� c <br /> The soil excavated from Site 1 was an estimated volume of 444 cubic yards, <br /> and the soil excavated from Site 2 was an estimated volume of 1,467 cubic <br /> yards Figures 3 and 4 illustrate all confirmation sample locations and <br /> excavation details for Sites 1 and 2, respectively Additional site-specific <br /> details of the soil excavation activities at Sites 1 and 2 are provided below <br /> Site 1 Soil Excavation <br /> The Site 1 soil excavation activities were initiated on 15 October 1993 <br /> following removal of the site asphalt cover and the railroad tracks overlin <br /> the estimated area of excavation The Site 1 excavation extended to a depth of <br /> (9-feet with areal dimensions of 25 feet in length and 20 feet in width <br /> (inclusive of side slope dimensions) For excavation in the proximity of the <br /> building, shoring equipment was installed in the east-west direction to <br /> support the building structure Some seepage of ground water was <br /> encountered at excavation depths below seven feet Soil excavation <br /> proceeded until either the cleanup goals were attained at the excavation <br /> sidewalls and bottom or until building structures prevented further <br /> excavation Twelve soil samples were collected from the excavation bottom <br /> as well as the sidewalls to confirm the cleanup goals <br /> Prior to backfilling Site 1 with clean dirt, the saturated bottom of the <br /> excavation was stabilized by laying out a geotextile fabric (Amoco 4545) <br /> covered with a four-foot-thick rock base consisting of one- to two-inch- <br /> diameter size rock The remainder of the excavation was backfilled using <br /> clean dirt compacted in 6- to 8-inch lifts using conventional construction <br /> equipment The soil was compacted to 90 percent to prevent excessive <br /> settling The compaction was verified with a nuclear density gauge The <br /> backfill operations were completed on 25 October 1993, and the site was <br /> subsequently paved with a 4-inch asphalt cover to match the existing grade <br /> Site 2 Soil Excavation <br /> The Site 2 soil excavation activities be an on 4 October 1993 following <br /> removal of the site asphalt qpyer, The excavation extended to a depth of <br /> approximately 8 to 9 feet with areal dimensions of 115 feet in length and 40 <br />