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' material was present from approximately 6 to 12 feet bgs. In an effort to <br />determine the extent of this material, it was excavated but kept in the SHT <br />t excavation between 20+00 and 20+50. The excavation was opened to <br />approximately 12 feet bgs where a small amount of free product began pooling in <br />the bottom of the excavation along with approximately 200 gallons of <br />groundwater. Excavation activities were discontinued over concern that this <br />material constituted hazardous waste. Excavated and disposed of 1,163 cubic <br />yards (69 truckloads) of soil the Allied Tower Road Landfill. Completed gross <br />removal and direct loading of soils considered to be non-hazardous. <br />February 20, 2007 - Eighteen roll-offs with 6-mil plastic for lining were delivered <br />to the site for excavation of soil remaining in the SHT considered to have the <br />potential to be characteristically hazardous. This included soils: 1) in the area of <br />19+00 below 7 feet; 2) sm 22+90; 3) 22+00 5CSL@6'; and 4) soil that was <br />removed from the area 19+50 near the deep pocket containing free product that <br />was not placed on trucks but left in the SHT between 20+00 and 20+50. The roll- <br />offs were all filled to near full (17 yards) and placed in the area north of the <br />pipeline release in preparation of slurry wall completion by GeoCon. <br />A total of 2,965 cubic yards of soil was excavated from this area for direct transport to <br />the landfill. Approximately 306 cubic yards of soil was placed in lined roll-offs and <br />temporarily left on site for future disposal determination. <br />' The SHT excavation was backfilled by using clean soil from the northern portion of the <br />site within one week of completion of the excavation. The soil was compacted to 95% <br />proctor in preparation for excavating to place the slurry wall and to prevent caving. <br />On March 12, 2007, three of the 18 roll-offs were randomly selected and sampled for <br />waste characterization and disposal options. Based on the lab results, the material was <br />' acceptable for disposal as a non-hazardous special waste at a licensed solid waste <br />landfill. The results of the sampling are included on Table 2C. The laboratory reports <br />from this sampling are included in Appendix 4. <br />The roll-offs were removed from the site for transport to the Allied Tower Road landfill on <br />March 19 - 26, 2007. The roll-off pickup and removal timeframe was protracted due to <br />very muddy site conditions. <br />The waste disposal manifests for all the removed soil is included in Appendix 5. <br />' 4.3 Slurry Holding Trench - Petroleum Impacted Water/Product Pumping and <br />Disposal (February 17-18. 2007) <br />As discussed above, on February 15, 2007 a deep pocket of slurry was found and <br />excavated to approximately 12 feet bgs. The bottom of the excavation filled with product <br />and water. E-21 contracted ACI Services, Inc., of Englewood, Colorado, to perform total <br />fluid recovery using dual phase extraction equipment. Photos of these activities are <br />' included in Appendix 3. <br />The water and product mixture was pumped into 300-gallon plastic and aluminum <br />' reinforced totes. The totes were placed in an earthen berm lined with 6-mil plastic until <br />waste characterization sample results could be analyzed to determine disposal criteria. <br />A composite sample was collected from the totes and submitted to Origins Laboratories <br />for analysis. The sample contained elevated BTEX concentrations. A total of 2,400 <br />5