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r <br /> The following sections describe the installation, sampling and analysis to be performed for each <br /> monitoring well installed <br /> ' 3.3.1 Monitoring Well Installation <br /> ' Monitoring well installation permits will be obtained, as necessary, for the monitoring wells before <br /> drilling begins Underground Service Alert (USA) will be notified to marls all underground <br /> utilities in the vicinity of anticipated boring locations All overhead utilities or other obstructions <br /> ' will be noted and referred to the driller prior to rig setup on any boring location <br /> Each monitoring well will be installed into a previously drilled soil boring The borehole will be <br /> ' advanced using a hollow stem drill rig with a minimum outside hole diameter of eight inches <br /> Each boring to determine the lateral extent of the contaminant plume will be advanced no more <br /> than ten feet below the ground water table interface, or until a competent clay layer is <br /> ' encountered below ground water The boreholes will then be completed as ground water <br /> monitoring wells The ground water monitoring wells will be constructed of 2-inch inside <br /> diameter (ID), flush threaded schedule 40 PVC casing and 0 02-inch factory perforated screen A <br /> ' filter pack of clean #3 silica sand will be installed in the annulus of the well boring from the base <br /> of the well boring to approximately 2 feet above the screened interval A two feet thick seal of <br /> bentonite chips will be installed in the boring annulus above the sand filter pack and hydrated with <br /> ' potable water A cement/bentomte slurry grout will be used to seal the borings from the top of <br /> the bentonite seal to the surface All wells will be completed above the existing grade and <br /> completed using 8 to 10 inch diameter steel well monuments set in concrete Each well <br /> monument will extend approximately 30 inches above the ground surface and be secured with a <br /> padlock Each well head will be secured with a water-tight well cap A schematic diagram of the <br /> proposed monitoring well construction is included in Appendix C <br /> The deep ground water monitoring well will be installed to test for possible vertical migration of <br /> contamination This borehole will be advanced in a similar fashion to the other wells, but the well <br /> will be completed to a depth of approximately 45 feet below ground surface Five feet of 0 02 <br /> inch factory perforated screen will be placed in the well from a depth of approximately 40 to 45 <br /> ' feet The well will be completed by sand packing the screen up to a depth of approximately 38 � <br /> feet and then filling the annulus of the well with granular bentonite or bentonite chips up to the 9- <br /> standing water level and from there to the surface with a cement/bentonite slurry grout The well <br /> ' will be completed in a monument as described for the other monitoring wells a� <br /> All monitoringwells will be drilled b a California State licensed drilling contractor with <br /> Y g <br /> ' experience in environmental projects Soil drill cuttings generated during soil boring and <br /> monitoring well installation will be stored on-site to await ultimate remediation and or disposal <br /> ' Prior to drilling each well boring, all drilling and sampling equipment will be thoroughly <br /> decontaminated as specified in the QAIQC Plan (Appendix A) Monitoring well locations and <br /> elevations to the point of measurement (POM) scribed in the well casing will be surveyed by a <br /> licensed California surveyor to 0 01 foot accuracy and locations and elevations will be plotted on <br /> a site plan map for inclusion in the final report <br /> American Geological Services,Inc. <br /> CA95DE-029 <br /> ,� 10 � <br />