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Interim Remediation Work Plan 419 S.Main Street,Manteca.,CA June 25,2003 Page 4 The drill cuttings and steam cleaning effluent will be placed in DOT-approved 55-gallon drums, sealed, labeled, and left on-site pending laboratory analyses. Disposal of hazardous materials, if any, will be the responsibility of the property owner. 3.3 EXTRACTION WELL INSTALLATION The extraction well EW-1 will be constructed with 25 feet of 4-inch outside diameter, Schedule 40, flush- threaded, machine-slotted PVC screen(slot size 0.010). The extraction well will be installed deep enough to allow five feet of slotted casing to be above and 20 feet of slotted casing below the static water table level at the time of the well installation. A flush-threaded PVC bottom cap will be placed at the bottom of the i, screen section. Blank PVC casing will be installed above the screen to the ground surface. A filter pack of#3 Monterey sand will be placed in the annular space to approximately three feet above the screen while the auger is in place. The depth of the sand in the well annulus will be monitored with a weighted tape measure while the sand is being placed and the auger is being gradually retracted to avoid bridging. To form a protective seal, approximately three feet of bentonite pellets will be installed above the sand as the augers are retracted. The bentonite will be hydrated using potable water. A surface seal of neat .r cement will be poured into the annulus and will extend from the bentonite to the ground surface. Depending on the stability of the borehole, the augers may be removed before or during emplacement of the grout. The v extraction well will be completed at the surface with a flush mount locking traffic box. A proposed well construction diagram is shown on Figure 3 in Appendix A. At least 48 hours following construction, the extraction well will be developed by surging and bailing the groundwater in the well until the discharge water is relatively free of sediment (clear to the unaided eye). The extraction well will be purged until the temperature, electrical conductivity, and pH of the water has stabilized. All well-development equipment will be cleaned prior to use in the well by washing in a solution `r of laboratory-grade, non-phosphate detergent and deionized water, and double rinsing with deionized water. The purge water discharged from the well during development will be placed in 55-gallon drums, sealed, labeled, and left on-site pending results of laboratory analyses. V 4.0 MONITOR WELL DESTRUCTION AND INSTALLATION PROCEDURES This section includes a description of the site preparation, the monitor well destruction procedures, the drilling procedures, and the monitor well installation. 4.1 SITE PREPARATION Condor will complete well destruction and installation permit applications and obtain the required permits from the SJCEHD prior to the commencement of fieldwork. Condor will schedule and coordinate all field V activities through Boyett and the SJCEHD. The proposed drilling location will be marked with white paint and USA will be notified at least 48 hours in advance of the fieldwork to locate, identify, and mark underground utilities in and near the work area. However, because companies contacted by USA may not +-+ identify utilities past private property lines and into the site, it is the responsibility of Boyett to locate, identify, and mark any utilities on their property. v 4.2 WELL DESTRUCTION PROCEDURES Prior to commencement of fieldwork, a tailgate safety meeting will be held and a site-specific Health and Safety Plan will be discussed with, and presented to, all field personnel for their signatures. Monitor wells i �' F , i� CONDOR L