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' PROPOSED SITE INVESTIGATION UNDERGROUND UTILITIES Prior to conducting any drilling activities at the site, the location of underground utilities will be checked by reviewing available blueprints of the site and by contacting Underground Service Alert. If necessary, the services of a professional underground locating company will also be utilized. In addition, a soil probe and/or magnetic locator may be used at drilling ' locations where the presence of underground utilities remain unknown. The upper 3 to 5 feet of each borehole will be advanced using a hand auger or similar device. ' SOIL SAMPLING ' Samples of the subsurface soils will be collected in the area surrounding the former glycol reboiler unit and production fluids tank. Borings will be drilled and sampled in the northern half of the site, and at off-site locations to the north and east of the former glycol reboiler 1 (Figure 2). The purpose of the sampling will be to determine the presence or absence of petroleum hydrocarbons in the subsurface soils at the site. ' Eight of the nine boreholes will be drilled using a truck -mounted drill rig equipped with 8 or ' 10 -inch O.D. hollow -stem, continuous -flight augers. The remaining borehole, located east of the facility, will be advanced and sampled using a hand auger or portable soil coring equipment due to limited access. The exact number and location of the boreholes may change due to conditions encountered during the field activities. All drill bits, drill rods, augers, and associated soil sampling equipment will be steam -cleaned prior to each use. ' The exploratory soil borings will be drilled and sampled to the vertical extent of the petroleum hydrocarbons in soil (as determined by a photolonization organic vapor meter) or the first occurrence of groundwater (whichever is shallower). Subsurface soil samples will be collected at intervals no greater than 5 feet using a 2 -inch or 2 'k -inch I.D. split spoon sampler, a standard penetration sampler, or a continuous coring device. The hand auger hole may be terminated at a shallower depth due to advancement refusal. The boreholes will be logged ' by a qualified field geologist under the supervision of a California Registered Geologist. At the conclusion of each day, all boreholes will be backfilled with a neat cement grout from the total depth to the ground surface. iThe following procedures will be employed when collecting and handling soil samples: 1. Prior to sampling, the split spoon sampler (or equivalent) and sample liners ' will be thoroughly washed with a trisodium phosphate solution and rinsed with potable water. cca09-23-92/8787a.51/cp31 5