Laserfiche WebLink
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 />in 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 #A159W01.1.5 <br />