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t + <br /> n TERRA VRC <br />� 0 <br /> DRILLING REPORT <br /> FORMER CHEVRON STATION 94054 <br /> 2103 COUNTRY CLUB BOULEVARD <br /> STOCKTON, CALIFORNIA <br /> PROJECT No. 30-0212 <br /> 1.0 INTRODUCTION <br /> The site, located at 2103 Country Club Boulevard in Stockton, was formerly a Chevron Service <br /> Station. During October of 1988, six underground storage tanks (USTs) were removed from the <br /> site. Subsequent environmental investigations have confirmed the presence of petroleum <br /> hydrocarbons in the soil and groundwater beneath the former service station site. Currently the <br /> site is a vacant lot. <br /> At the request of the San Joaquin County Environmental Health Department, two additional <br /> exploratory boring were drilled. Chevron contracted Terra Vac to complete this phase of work <br /> at the site. <br /> 2.0 FIELD INVESTIGATION <br /> On March 16, 1995, Spectrum Exploration, Inc., under the direction of Terra Vac, drilled and <br /> completed two groundwater monitoring wells (MW-8 and MW-9). Well MW-8 was installed <br /> on-site and Well MW-9 was installed off-site. The locations of the wells are presented on <br /> Figure 1. A CME 75 truck mounted drill rig was used. Hollow-stem augers were used to drill <br /> the borings. The total depth of each well and screen interval were determined in the field based <br /> on PID measurements, lithologies, and groundwater levels. <br /> i <br /> Soil samples were collected from each boring using a modified split-spoon sampler. The <br /> sampler was driven eighteen inches ahead of the augers using a standard 140 pound hammer <br /> repetitively dropped 30 inches. A minimum of three samples per boring were collected for <br /> lithology classification and volatile screening analysis. A hand-held PID (Thermoenvironmental <br /> Instruments 580A) was used to examine each set of soil samples collected. The Unified Soils <br /> Classification System was used to describe the soil samples. <br /> Each well was constructed of Schedule 40 PVC well screen and riser. Well screen slot size is <br /> 0.020 inches. The filter pack for each well consists of Lone Star #3 grade silica sand. A <br /> minimum two foot-thick bentonite seal (hydrated 318" pellets) was placed between the filter pack <br /> and the adjacent grout well seal. The well seal is composed of neat cement grout. Well logs <br /> containing well construction information are presented in Appendix A. All wells were <br /> completed below grade. Each well was secured with a locking cap. A traffic rated well box was <br /> placed over each well. <br /> Prciea Mo.301212 <br /> nprd 3,1"5 <br /> i <br /> I <br />