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�1 <br /> tion of that particular probe is outside the perimeter of the concrete slab. <br /> Following completion of each probe , the hole will be grouted in with a <br /> bentonite/cement grout. <br /> The probing will be conducted along pre-established transects. The initial <br /> four transects to be undertaken are shown on Plate 2. During these initial <br /> probe transects , the first two probe holes installed will be at the beginning <br /> and at the end of the planned transect, in two locations believed to be within <br /> i and outside of the concrete perimeter, respectively. This will verify that the <br /> technique can successfully identify the presence or absence of the concrete <br /> slab. We will then step locations in a methodical manner (as shown on Plate 4) <br /> to locate the edge of the concrete slab to within a 10-foot tolerance. Addi- <br /> tional transects will be performed as necessary. <br /> I, Between probe holes, the steel rod will be thoroughly cleaned with a dilute <br /> trisodium phosphate solution and a fresh water rinse in order to minimize the <br /> possibility of cross-contamination between probe holes. <br /> Logs of the borings will be maintained using the form shown in Plate 5. <br /> Soils will be classified according to the Unified Soil Classification System <br /> (Plate 6). Field notes and observations will be recorded daily on Dames & Moore <br /> ' field memo sheets shown in Plate 7. <br /> Backhoe Pits <br /> After completion of the probing program, backhoe pits will be excavated at <br /> ' the concrete perimeter along at least three of the probe transects as determined <br /> by the results of the probe program described above. Appropriate permits will <br /> be obtained from the City of Tracy prior to any pit excavation. These test pits <br /> will expose the lateral limits of the concrete in order to confirm the results <br /> of the probing and to visually document the presence and status of the 4-inch <br /> thick concrete slab. Excavation will be accomplished under the supervision of a <br /> g� Dames 6 Moore geologist or engineer by a local operator trained in the excava- <br /> tion of potentially contaminated soils. The dimensions of each pit will be as <br /> E small as possible , probably on the order of 10 feet long, 2-3 feet wide, and <br /> 5-7 feet deep. After excavation, each pit will be left open for 2-3 hours to <br /> allow observation of any oil inflow. If free oil accumulates, a sample will be <br /> JED2/H -3- <br />