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I IAll drill cuttings will be collected in Department of Transportation (DOT)-approved 55-gallon drums and . will remain on-site pending proper disposition Soil cuttings will be managed in accordance with SJC I guidelines If a boring is not completed as a well (for example, if unable to advance boring to groundwater), it will be backfilled through a tremie pipe with bentonite grout from total depth to approximately 1 foot bgs, and capped with concrete to the surface An ATC staff scientist will complete ' lithologic logs for each boring in general accordance with ASTM Method D 2488-90 Boring Log Notes, Method of Soil Classification, Soil Boring Graphics, and an edited boring log are included in Appendix B I5.4 Organic Vapor Monitoring To obtain preliminary data regarding the degree of potential petroleum hydrocarbon-impact to soil and for ' health and safety concerns, a representative sample will be collected at each soil sampling location and field screened for volatile organic vapors utilizing a hand held photo-ionization detector (PID) in general I accordance with ATC's Standard Operating Procedure - Field Soil Vapor Monitoring, which is included in Appendix A PID readings will be recorded in the boring logs 5.5 Well Installation Following completion of proposed borings MW-13 through MW-17, the borings will be completed as ' groundwater monitor wells The proposed construction of MW-13 through MW-17 will consist of 40 feet (surface to 40 feet bgs) of blank 2-mch, Schedule 40 PVC casing, and 25 feet of slotted (0 020-inch slots) 2-inch Schedule 40 PVC well screen To compensate for an observed historical increase in groundwater lie elevation observed in previous assessments and to provide a sufficient screened interval to include these wells as observation points during an aquifer pump test, the well screen will extend from approximately 10 feet above the static water level to approximately 15 feet below All well casing and screen will be delivered to the site in factory-sealed containers I The annulus of the screened portions of the monitor wells will be backfilled with a #3 Monterey sand (or equivalent) filter pack from approximately 39 to 65 feet bgs The filter material will then be settled by surging the well with a surge block Adding more sand prior to placement of the bentonite seal will compensate for any settlement A 2-foot layer of bentonite pellets will be placed on top of the upper filter pack and hydrated to form an annular seal from 37 to 39 feet bgs Bentonite grout will be placed from 2 to 37 feet bgs The well will be completed from 2 feet bgs to the ground surface with a watertight, flush- mounted, traffic-rated vault slightly raised for drainage and set in a 3-foot diameter concrete perimeter ' seal Construction details are illustrated in Figure 5 Following completion of boxings VEAS-1 through VEAS-3 the borings will be completed as a dual completion vapor extraction/air sparge wells The borings will be drilled to approximately 65 feet below ground surface The vapor extraction portion of the wells will be constructed of a 4-inch PVC casing screened from 15 to 50 feet (0 020-inch slots) The air sparge well will be constructed of a 1-inch EZ 100966SAFSWP ATC Associates Inc S 1EZ Serve\FZ 1009661Reports1100966SAFSWP ATC Project No 43 25827 0026 I 8