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� � �_ <br /> • <br /> lid <br /> Quik Stop Market No. 132 <br /> Project No.349132-31 September 19, 1990 <br /> P Page 3 <br /> to The wells were constructed of 2-inch-diameter, schedule 40, flush-threaded polyvinyl <br /> chloride(PVC)slotted screen(0.01-inch)and unslotted casin • noglues <br /> used. After drilling each boring to the desired depth,the PVC casinwas installednthrough <br /> [ the hollow-stem auger. As the auger was withdrawn, sand was slowly poured down the <br /> borehole annulus to approximately 2 feet above the slotted screen section. After e s <br /> and <br /> t;$ was poured, the well was surged causing the sand pack to settle and compact. Additional <br /> ► sand was used to bring the sand pack to the desired depth. Above the sand,approximately <br /> 2 feet of bentonite was used as a seal. The remaining <br /> ar space was <br /> sealed with a neat cement mixed with 5% powdered entoniteilion runder the f the superrvison of <br /> Steven K. Schneider,Environmental Health Specialist,San Joaquin County public Health <br /> Services. LIl top of each well was set in a traffic-rated water-tight vault box sli tly above <br /> 11,4 grade, and an expansion cap was used to provide security. A concrete surfal was <br /> I installed to complete the well construction. Exploratory boring logs and mo ' ring well <br /> details are in Appendix B. <br /> Well vel meat <br /> After construction,the wells were developed using a surge block to agitat et the sand <br /> pack around the annulus of the well casing. A bailer <br /> g was used to m�u�nave water <br /> after each surge. Well development(a) removes residual silts and clays left from the <br /> drilling, and (b)improves the hydraulic conductivity between the wells and the natural ` <br /> <m formation. .After development the wells were allowed to recharge with water from the <br /> surrounding formation,enabling Exceltech to collect a representative water sample and to <br /> measure the thickness of any floating product if encountered. Mr. Schneider directed <br /> Exceltech to sample the well immediate) after devel <br /> Y opment. <br /> iF All water Coll rcted during well development was placed in Department of Transportation <br /> [ [DOT]; 17E drums and left on-site until laboratory anal;ses are complete. At that time the <br /> drums may be properly disposed of by the client. ' <br /> Groundwater S;mn_lino <br /> Groundwater samples were collected from the wells on September 14, 1990. Before <br /> i <br /> sampling,a clear acrylic bailer was used to field check each well for the presence of floating <br /> product: none was detected. After the field check, the wells were sampled following <br /> g - - <br /> Exceltech's ground sampling protocol(Appendix Q. A minimum of four well-casing <br /> volumes of groundwater were purged from the wells before sampling. The groundwater <br /> purged from-the wells and equipment rinse water were placed in DOT-approved drums and <br /> left on-site pending results of the laboratoy analyses. <br /> y <br /> _ - a : <br />