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Ms . Casey Foley <br /> January 2 , 1991 <br /> Page 5 <br /> We understand that the excavation has been backfilled <br /> by RAMCON with suitable clean pea gravel , with the approval <br /> of the San Joaquin Local Health District, and covered with <br /> concrete . <br /> With the permission of the SJLHD and because TPHg and <br /> BTEX detection limits were considered unacceptable by the <br /> county, Roger Foott Associates, Inc. proposes to drill three <br /> soil borings in locations corresponding to the previous <br /> samples . Because the tank cavity has been backfilled with <br /> pea gravel , we propose to drill the borings directly to <br /> points 10 feet (in the location corresponding to the waste <br /> oil tank) and 15 feet (at each end of the former gasoline <br /> tank) . Samples will be collected at those points . and <br /> analyzed by Mobile Chem Labs using detection limits of 0 . 005 <br /> ppm for BTEX and 1.0 ppm for TPHg. <br /> The borings will be backfilled using drill cuttings <br /> (expected to be largely pea gravel ) and capped with at least <br /> 12 inches of concrete so that they are even with the <br /> surrounding grade . <br /> The area of the former dispenser and sample S-2-4 will <br /> be excavated using a backhoe operated by RAMCON . The <br /> excavation will proceed until field evidence and field <br /> instruments (photoionizing organic vapor meter) show no <br /> indication of contamination. Approximately five soil <br /> samples will be collected from the walls and base of the <br /> excavation using hand sampling equipment . The samples will <br /> be collected either from the soil in place or from the <br /> backhoe bucket using methods described above and as, <br /> described in the LUFT Manual . <br /> ROGER FOOTT ASSOCIATES, INC. <br />