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r Geological Technics Inc. N%001 Page 2 <br /> Tank Closure Report <br /> MCGranahan (Gawne Road) <br /> ` Project No.251.0 <br /> December 9,1994 <br /> 2.0 Removal of the Underground Storage Tank <br /> Don Light of Del-Tech Geotechnical Support Services excavated soil from around <br /> the UST and prepared the tank for removal. The following observations were <br /> made during this work. <br /> • Preparatory work for tank closure was started on November 14, 1994 and the <br /> _ tank was removed on November 15, 1994. <br /> • The tank was not in a bed or sand of pea gravel, to retard corrosion, but was <br /> surrounded by and covered with clay rich native soil. <br /> • Mrs. L.T. Briggs was on site during the removal of the tank <br /> • Capacity of the tank was approximately 500 gallons. <br /> • The tank was at a slight incline. <br /> • The tank contained a very small amount of product (gasoline) inside of it. It <br /> r, is unknown as to when the tank was installed, how long the tank was <br /> actually use, or when it was last used. <br /> • After the tank had been lifted from the excavation, it was noted that there <br /> were several large 1-2" holes located in the bottom. The tank was then rinsed <br /> onto a plastic tarp and then containerized in a DOT approved 55 gallon drum. <br /> Both the rinsate and the tank were disposed as follows: <br /> - The tank and piping were disposed of at A & S Metals in Modesto. <br /> - The rinsate was recycled by Enviropur West of Patterson, CA, a petroleum <br /> recycler. <br /> • Due to the holes in the bottom of the tank, the soil underneath it was <br /> impacted by the release of hydrocarbons. An attempt was made to dig-out of <br /> the hydrocarbon impacted soils, but it became apparent at 10 feet that this <br /> could not be accomplished. A tank pit sample was taken at that depth. <br /> • In the interest of time savings and gathering valuable information for <br /> ` planning the course of the project in the future, and since the equipment was <br /> on site, an exploratory pit was dug straight down under the tank to a depth of <br /> 17.5 feet. A sample was taken at 17.5 feet within this pit. The purpose of this <br /> ` work was to determine if hydrocarbon levels were attenuating rapidly <br /> enough attempt an over excavation procedure or to first perform site <br />