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Site Characterization:Clover*nWe School,51 East Beverly Place, Tracy, CA. Page 5 Boring PP-2 was located to the south (upgradient) from the former location of the pit that had contained the underground storage tank. As shown on Figure 2, this was a slant boring at an angle of 47.73 0. It was advanced so as to penetrate beneath the floor of the pit than had contained the underground storage tank. As is shown on the figure, the former location of the tank pit is obstructed by a building that is used for storage of playground toys and �- equipment. The alignment of the boring was such that it passed beneath the area of the site where the fuel-dispensing island had been located, close to the adjacent maintenance building. This boring was also advanced until refusal of the push probe occurred in dense, sandy gravel at a vertical depth of 10.35 feet BGS. The borings were continuously logged by a California-licensed geotechnical engineer. In both borings the characteristics of the sand and other soils were such that there were significant zones from which no sample could be recovered. However, it was possible to make a complete log of each boring by observing traces of soil adhering to the push probes and sampling tools. The boring logs are presented in Appendix C. Note that the log for boring PP-2 is presented as if the push probe had been advanced vertically—the depths shown on the log having been calculated from the linear distances down the boring and the angle of the hole from the horizontal. Mr. Harlin Knoll, Senior REHS with the SJCPHS, was present on site to observe the subsurface investigation work 3.2.2 Soil Sampling It was planned to take soil samples from the borings at 5 ft depth intervals. However, the lack of core recovery described above limited the number of samples obtained to three. One was recovered from boring PP-1 at a depth of 10 ft BGS and two, at depths of 5 and 14 ft. down the slanted hole, from boring PP-2. AW To recover the samples, a 4-ft long, split-spoon sampling tool, with a one-half inch diameter Teflon liner was introduced into the boring and driven Ar downward from the bottom of the hole at each four-foot depth interval. Depth-specific samples were selected by the engineer in those cases that a core was recovered in the Teflon liner. They were recovered by cutting off selected portions of the liner after it was removed from the split-spoon. In zones where core recovery was lost, it was caused by one or the other of the following two phenomena: 1) in some zones, the soil was a very wet and loose fine sand or silty sand that flowed out of the sample liners before the split-spoon reached the surface; and 2) in other zones, pieces of gravel blocked the bottom end of the one-half inch diameter split-spoon. When that occurred, soil did not enter the split-spoon liner from the depth at which the gravel was encountered to the sic