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April 11, 1996 �s <br /> Page 4 <br /> Health Administration CFR 1910.20. A site-specific health and safety plan will be <br /> prepared by PACIFIC prior to field activities. <br /> Excavation <br /> An initial trench will be excavated on the site of the former Unocal service station, <br /> parallel to the Eleventh Street sidewalk. The proposed trench will be similar in location <br /> to exploratory excavation TP-3 (Figure 1). The trench will be approximately 15 feet in <br /> length and approximately 4 feet in width. The trench will be excavated to a depth of <br /> 9 feet below ground surface (bgs) to expose the bottoms of the tanks (Figure 3). The <br /> trench sidewalls will be appropriately shored in accordance with OSHA regulations, <br /> prior to entrance into the trench. <br /> Soils generated during this project will be stockpiled on site for characterization and <br /> disposal. <br /> Tank Closure in Place <br /> Once the ends of the tanks are exposed, access holes will be drilled into each tank using <br /> a non-sparking drillbit. Each tank will than be gauged for the presence of liquids. If <br /> detected, the liquids will be evacuated from the tanks by a vacuum truck. The tanks will <br /> then be triple rinsed and purged using a pressure washer and vacuum truck. All fluids <br /> generated by rinsing process will be transported by a licensed transporter to a permitted <br /> treatment, storage and disposal facility. <br /> If the tapks are found to be dry during the initial gauging, than triple rinsing process will <br /> not be performed. <br /> Following the above activities, each tank will be completely filled with a neat <br /> cement/sand and bentonife slurry. The slurry will be injected into the tanks through the <br /> drilled holes. <br /> Soil and Groundwater Sampling Procedures <br /> ,One soil sample will be collected from beneath the exposed end of each tank. The two <br /> soil samples will be collected at a maximum depth of 2 feet below the tank bottoms. <br /> Soil samples will be collected by advancing 2-inch-diameter brass sample liners into <br /> in-place soils. Soil samples will be retained in the brass liners, labeled, and capped with <br /> Teflon sheets and plastic end caps. The samples will be placed in sealed plastic bags, <br /> placed on ice, and transported to the laboratory accompanied by the appropriate chain- <br /> of-custody documentation. <br /> 310097IMTANKWP.DOC <br />