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2373 Mariposa Road <br /> p August 16, 1999 <br /> Pro ect 9688 —Page 4 <br /> 06/14/95 EHD publishes letter requiring additional work after receipt on <br /> 12/05/94 of Wm J Hunter & Associates "Results of Soil <br /> Contamination Investigation and request for Site Closure" <br /> 04/13/99 Wm J Hunter & Associates returns all files to Husky Crane <br /> 06/11/99 WDE publishes a Work Plan for Soil and Groundwater <br /> Investigation <br /> 07/05/99 WDE publishes an Addendum to the Work Plan addressing <br /> 1specific concerns of EHD <br /> 07/30/99 WDE drills and samples on soil boring and collects a "grab" water <br /> sample for the first encountered water in the boring <br /> ' Site Geology, Soil Conditions and Hydrogeology <br /> The site is in the Lower Sacramento Valley geologic setting As such the soils <br /> in the area are alluvial extending many hundreds of feet before bedrock is <br /> encountered Based on review of borings at the site, the sods are fine grained <br /> composed primarily of silts and sand with a varying amount of sand <br /> ' Permeabilities of such soil are generally low <br /> Specific soil conditions encountered during the drilling were mainly cohesive <br /> soils with a significant clay or silt content Densities and moisture contents <br /> varied Groundwater was encountered in the boring at about 68 feet below <br /> ground surface <br /> Three nearbywater well records maintained b the San Joaquin Count Flood <br /> Y J q Y <br /> Control District (FCD) have been reviewed March 1999 records indicated the <br /> current depths to ground water in those wells were 50 to 60 feet below ground <br /> surface <br /> WORK ACCOMPLISHED <br /> ' Soil Drilling and Sampling <br /> On July 30, 1999, 1 soil boring (B1) was advanced with a truck mounted drill <br /> rig using 8 inch outside diameter, 3 3/4 inch inside diameter hollow stem <br /> augers at the location shown on Figure 2 and 3 of Appendix A <br /> The boring was sampled at about six feet below ground surface and at five foot <br /> intervals until groundwater was encountered at 68 feet The boring was then <br /> extended to 70 feet deep for the collection of a water sample Undisturbed soil <br /> samples were obtained by driving a California (2 5 inch diameter, split-barrel) <br /> Sampler containing 2 inch diameter, 6 inch long brass tubes into the <br /> "undisturbed" soil beyond the augers Driving energy was provided by a 140 <br /> pound hammer falling 30 inches in accordance with ASTM procedures The <br /> number of blows required to drive the sampler three successive 6 inch <br /> WILLIAM DUBOVSKY ENVIRONMENTAL <br />