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TOUCHSTONE DEVELOPMENTS <br /> 1b INTRODUCTION <br /> In May, 1994, three product underground storage tanks (USTs) and one waste <br /> oil tank, one sump and two semi-hydraulic hoists were removed from the k <br /> Chevron Service Station No 9-8632 The site is a former service station located <br /> at 575 West Grant Line Road in Tracy, California (Figure 1) This report <br /> documents field activities that occurred subsequent to the tank removal, <br /> including overexcavation activities and soil aeration and disposal <br /> A work plan for soil excavation and remediation, prepared by Touchstone <br /> Developments and dated July 18, 1994, was submitted and approved by the <br /> San Joaquin County Public Health Services (SJCPHS) Limited overexcavation <br /> was to be performed to remove hydrocarbon impacted soils identified during <br /> tank removal activities in the area of the former waste oil tank, sump, western <br /> hoist and southern pump island (Figure 1) Soil removed during overexcavation <br /> was to be stockpiled for disposal or aeration dependent upon type and level of <br /> contamination encountered <br /> Construction activities were performed by Golden West Construction of <br /> Livermore, California Soil sampling and aeration/disposal activities were <br /> performed by Touchstone Developments Site activities were observed by <br /> Brett Hunter of Chevron and Harlin Knoll of SJCPHD <br /> i <br /> SITE ACTIVITIES <br /> August 10,_1994 The former waste oil UST complex, and areas of the former <br /> station building which once contained the sump and hoists were overexcavated <br /> to a,depths ranging from 10 feet to 10 5 feet below grade surface (bgs) The <br /> area of excavation was defined based on sample results collected during tank <br /> removal in May (UST and Product Line Removal Report - Touchstone, June 20, <br /> 1994) Water was encountered in the excavation at 8 to 9 feet bgs, in <br /> insufficient quantity to sample The excavation was roughly square, <br /> approximately 30 feet wide and 34 feet long (Figure 2) Sidewall samples were <br /> collected from the excavation, (WX-1 through WX-11, Table A) <br /> August 17 1994 Excavation activities continued <br /> Based on analytical results (WX-10) the excavation in the waste oil <br /> tank area was expanded an additional 6 feet to the north <br /> (Figure 3) Soil samples were collected, (WX-12 through WX-14, <br /> Table A) <br /> Exploratory trenches were dug and sampled in the former location <br /> of the southern pump island Samples were collected from the <br /> Chevron Station#E9-8632 1 <br />