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Additional SoiI i d Groundwater Investigation Work Plan Raymond Investment Corporation May 19,2006 Page 5 groundwater up inside the tubing. The groundwater samples will be discharged directly from the tubing into laboratory-supplied sample containers: The sample containers will be sealed, labeled, placed in a cooler chilled with Blue Ice®, and delivered under chain-of-custody procedures to a California-certified laboratory for analyses. 4.3 MONITORING WELL INSTALLATION FIELD PROCEDURES One 4-inch7diameter monitoring well will be installed. The monitoring well boring will be drilled using an 8-inch O.D. continuous-flight hollow-stem auger. Drilling activities will be performed under the IIS supervision of a Condor geologist in accordance with the provisions of the SJCEHD ermits. Drill P g g p P cuttings from the monitoring well boring will be logged in accordance with the USCS. Descriptions of soil types encountered will be recorded on a geologic log. Soil samples will be collected from the drill cuttings for the purpose of characterizing the cuttings for disposal. All down-hole drilling equipment will be steam-cleaned prior to use. The drill cuttings and steam cleaning effluent will be-placed in DOT- approved 55-gallon drums, sealed, labeled, and left on Site. Disposal of hazardous materials, if any, will be the responsibility of the property owner. The monitoring well boring will be drilled to a depth of approximately 10 feet below the water table. It is anticipated that groundwater will be first encountered at approximately 35 feet bgs. The monitoring well will be constructed with 20 feet of 4-inch O.D., Schedule 40., flush-threaded, machine-slotted PVC screen (0.010-inch slot size). The screen will extend from a depth of approximately 10 feet below the water ` table to 10 feet above the water table. A flush-threaded PVC bottom cap will be placed at the bottom of the screen section in the well. Blank PVC casing will be installed above the screens.to the ground surface. A filter pack of#2112 Monterey sand will be placed in the.annular space to approximately two feet above the screens'while the augers are in place. The depth of the sand in the annulus of the well will be monitored with a weighted tape measure while the sand is being placed and the augers are being gradually retracted to avoid bridging. To form a protective seal, approximately five feet of bentonite chips will be installed above the sand in the well. The bentonite chips will be installed as the augers are retracted. The bentonite will be hydrated using potable water. A surface seal of neat cement will be tremied into the annulus of the well and will extend from the bentonite to the ground surface. A �! generalized monitoring well construction diagram is included as Figure 4,Appendix A. {� The monitoring well will be completed with locking traffic boxes installed flush with the ground surface. 'Details of the well construction will be noted on the geologic log, including the depth intervals of the screen, sand pack, and seals. 4.4 MONITORING WELL SURVEYING, DEVELOPMENT,AND SAMPLING Following installation of the monitoring well, the well will be surveyed to determine the location and elevation of the well collar in order to comply with AB2886 (Water Code sections 13195 — 13198). The �} well collar will be surveyed with a vertical accuracy of 0.01 foot to a NAVD 88 or NGVD 29 datum, and h• with a horizontal accuracy of 0.03 foot to a NAD 83 datum. The measuring point for water-level measurements will be marked on the well collar. Well survey data will be "submitted in electronic deliverable format(EDF)to the State Water Resources Control Board UST site database (GeoTracker). At least 48 hours following construction, the monitoring well will be developed by surging and bailing . the groundwater in the well until the discharge water is relativcly free of sediment (clear to the unaided eye). The monitoring well will be.purged until the temperature, electrical conductivity, and pH'of the water have stabilized. All well-development equipment will be cleaned prior to use by washing in a Li/a CONDOR