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i <br /> 16 One soil sample from each boring was transported under chain-of-custody procedures <br /> and submitted to the analytical laboratory for analysis The sample from each boring was <br /> ' the sample with the highest headspace reading using the methodology described above <br /> When headspace testing did not yield the presence of volatile organic compounds, the <br /> sample for analysis was selected by the site geologist Soil samples submitted to the <br /> ' analytical laboratory were analyzed for constituents as described in Section 3 2 3 <br /> ' Each borehole was completed as a ground water monitoring well upon completion of <br /> drilling to the appropriate depth Each ground water monitoring well was constructed of <br /> 2-inch inside diameter (ID), flush threaded schedule 40 PVC casing and 0 02-inch factory <br /> ' perforated screen Wells MW-7 and MW-8 were constructed with 20 feet of screened <br /> casing and MW-9 was constructed with five feet of screened casing A filter pack of <br /> clean #3 silica sand was installed in the annulus of the well boring from the base of the <br /> ' well boring to approximately 2 feet above the screened interval A one foot thick sea] of <br /> bentonite chips was installed in the boring annulus above the sand filter pack and <br /> hydrated with potable water for wells MW-7 and MW-8 A ten foot thick bentonite seal <br /> ' was installed in well MW-9 A cement/bentonite slurry grout was used to seal the <br /> borings from the top of the bentonite seal to the surface The cement grout was installed <br /> using a tremrnie method for MW-9 Monitoring wells MW-7 and MW-8 were completed <br /> flush to the existing grade in water-tight traffic rated well boxes Monitoring well MW-9 <br /> was completed using a steel well monument set in concrete which extends approximately <br /> 24 inches above the ground surface and secured with a padlock Each well head is <br /> secured with a water-tight well cap Monitoring well construction diagrams are included <br /> on the well boring logs contained in Appendix B <br /> All monitoring wells were drilled by a California State licensed drilling contractor with <br /> experience in environmental projects Soil drill cuttings generated during monitoring <br /> ' well installation are stored on-site to await ultimate remediation and or disposal <br /> Prior to drilling each well boring, all drilling and sampling equipment was thoroughly <br /> decontaminated Monitoring well locations and elevations to the point of measurement <br /> (POM) scribed in the well casing were surveyed by a licensed California surveyor to 0 01 <br /> foot accuracy <br /> 3.3.2 Development and Ground Water Sampling of Monitoring Wells <br /> ' All ground water monitoring wells were allowed to set for at least 24 hours following <br /> their completion Each well was then developed by alternately surging and pumping <br /> ' using a manual surge block and 12 volt submersible pump Well development continued <br /> for at least one hour or until the field geologist determined that the water was reasonably <br /> { clear and free of silt and sediment All well development water was containerized on-site <br /> € in metal 55 gallons drums for remediation and/or disposal pending laboratory results <br /> American Geological Services, Inc <br /> CA95DE-029 <br /> 1 7 <br />