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r f. H.KLElNFELDER&ASSOCIATES f� Pile No. W-2004-1 , ` October 28, 1985 9 Page 2 w Field Activities/Observations a. Soil Borings The location of soil borings B-1 and B-2 are shown on Plate li. Boring B-I was placed adjacent to the former storage tank site. The borings were drilled using a truck mounted mobile B-6: drill rig equipped with 6-inch continuous flight augers. A description of the soil encounteret.! is presented in Appendix A with a copy of the o Unified Sall. Classification System (used to identify the soils). The soilencountered w during drilling consisted of interbedded sand, silty sand, silt, clayey silt, and silty clay. Groundwater wtis encountered at 43 feet from the ground surface. Barings were advanced to a total depth of 60 feet. b. Monitoring Wells Groundwater monitoring wells were constructed in the soil borings at the t completion of drilling and logging. The groundwater wells were completed with a 2-inch inside diameter PVC pipe, with well screen sections perforated with 0.020-inch ° t slos from 30 to 60 feet below the ground surface. The annular space between the ` pipe and the wall of the boring was backfilled with Montereysand to ! approximately 3 ' 1-foot above the to of the p perforated section. .'1 1-foot bentonite plug, covered with slurry cement, was placed above the sand pack to provide a seal against water infiltration. The well was placed inside a locking cristy box. a e. Sampling Procedure Soil samples were collected at the time of drilling for chemical analyses. These samples were collected from the surfaceh to the groundwater at S-foot intervals. Sail 4's _ i samples were collected by advancing the boring to a point immediately above the sample, and then driving a Modified California Sampler into the soil through the cent4mr �.. s L.