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Geological Technics InO 0 Page 2 <br /> Sinclair Trucking <br /> Report-Subsurface Investigation <br /> Project No.320.2 <br /> ' September 27,1995 <br /> 1.2 Monitoring Well Installation <br /> To further investigate the extent of gasoline range petroleum hydrocarbons in the <br /> soil and groundwater environments, Geological Technics Inc. supervised the <br /> installation of three groundwater monitoring wells (MW-1, 2, & 3) in positions <br /> surrounding the suspected point of release (Figure 2 Site Map). <br /> The well borings were advanced to a total depth of 20 feet below surface grade using <br /> a 8,00 inch outside diameter continuous flight hollow stem auger owned and <br /> r operated by V&W Drilling (C57# 658786). Soil cuttings underlain and covered with <br /> plastic. <br /> ' The three 2 inch diameter wells were constructed of flush threaded schedule 40 PVC <br /> casing with 15 feet of 0.010 inch perforations. A #3 Monterey sand surrounded and <br /> extended one foot above the perforations. The wells were surged using a surge <br /> r block to settle the filter pack before the granular bentonite transition seal was <br /> installed and hydrated. The annulus was sealed using a neat cement grout installed <br /> with a slurry pump and tremie pipe. The wells were completed with a locking <br /> water tight cap enclosed in a flush mounted water tight traffic box. The annular seal <br /> was completed integral with the installation of the well box. The well top of casing <br /> measuring points were surveyed by a licensed land surveyor. An as-built <br /> ' monitoring well construction schematic is attached as Figure 4. <br /> After the well sealing materials had set (for a period greater than 24 hours), the well <br /> rwas developed (using mechanical surging and pumping methods) until a clear <br /> stream of water was obtained. All development water was containerized in 55 <br /> ' gallon DOT approved containers and stored on site. <br /> 1.3 Soil Sampling, Geologic Logging, and Subjective Observation <br /> ' Soil samples were collected for geological and analytical evaluation at five foot <br /> intervals. A boring log providing sediment description using the U.S.C.S. and field <br /> r observations was maintained by a professional geologist working under the <br /> supervision of a registered geologist. Soil samples were collected in 6.0 inch brass <br /> liners using a 2.0 inch modified California split spoon sampler. All soil samples <br /> ' were sealed with Teflon or aluminum foil, capped, labeled and placed in a cooler <br /> with crushed ice at 4° Celsius for transport to the laboratory following Chain of <br /> Custody protocol. <br /> ' Because every soil sample collected was not submitted for laboratory analysis, a <br /> screening process was used to gather additional information through field <br /> r <br />