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t <br /> 5 1 Soil Excavation and Tank Removal <br /> Prior to tank removal the entire tank cavity (both old and new) will be shored with steel <br /> sheet piles The shoring will facilitate the removal and installation of the USTs and will <br /> protect existing nearby structures and wells at the Site. <br /> Roux personnel will be present to observe the excavation of soil from the former UST <br /> cavity and the product line trenches, and the removal of the USTs and lines <br /> Immediately after the USTs and product lines are removed, Roux and the PHS-EHD field <br /> representative will inspect the USTs and piping for any evidence of damage or leakage <br /> Following removal of the USTs and piping, the tank cavity and piping trenches will be <br /> enlarged to the size necessary to accommodate the new double-wall USTs and associated <br /> piping The soil and artificial fill material within the shoring will be excavated to a depth <br /> of about 14 ft bgs (about four feet below ground water) No further excavation of soil <br /> Sin the tank cavity or piping trenches will be conducted Soil which contains petroleum <br /> hydrocarbons outside the shoring or below the piping trenches will be remediated in-situ <br /> using a vapor extraction system (VES) which is currently being designed by Brown and <br /> Caldwell. It is estimated that a minimum of 800 cu. yds of soil will be excavated from <br /> the tank cavity and piping trenches. The soil will be temporarily stockpiled on-site <br /> 5.2 Soil Sampling <br /> Soil samples will be collected from the base of the product line trenches at a spacing of <br /> about 20 linear feet at locations selected by the PHS-EHD field representative The <br /> samples will be collected from the native soil approximately one to two feet below the <br /> interface with the trench fill material <br /> Soil from the product line trenches will be brought up to the surface in the backhoe or <br /> excavator bucket. Soil samples will be collected in 2-inch diameter by 4-inch long, clean <br /> stainless steel tubes. Six to twelve inches of soil will be scraped away from the surface <br /> 4 Doc #A159WO1 15 <br />