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' • • Remediation Wel[Installation Work Plan New West Flag City Facility ' August 7 2008 6437 W. Banner Street, Lodi, California ' contractor will be selected based on the lowest bidder. The utility clearance will include notifying Underground Service Alert (USA) of the pending work a minimum of 48-hours prior ' to initiating the field investigation, and securing the services of a private utility locating company to confirm the absence of underground utilities at each boring location. ' A HASP will be prepared for use by personnel implementing the Work Plan. The HASP will address hazards associated with the proposed soil borings. A copy of the HASP will be available ' on-Site at all times. The subcontractor(s) performing field activities will be provided with a copy of the HASP prior to initiating work. A safety tailgate meeting will also be conducted daily ' to review the Site hazards and drilling work scope. 4.2 MONITORING WELL INSTALLATION ' Closure Solutions personnel will supervise the drilling of six off-Site well borings (EW-6A, ' EW-7A, EW-713, EW-813, EW-9B and EW-10A). Groundwater extraction wells EW-6A, EW-7A and EW-10A (Zone A wells) will be advanced to a total depth of 25 feet bgs and extraction wells EW-7B, EW-813 and EW-913 (Zone B wells) will be advanced to a total depth of ' 50 feet bgs. The proposed groundwater extraction well locations are illustrated on Figure 2. A hollow stem auger(HSA) drilling rig will be used to advance the borings. The groundwater extraction wells will be constructed with 4-inch diameter schedule 80 polyvinyl chloride (PVC) blank casing and a 0.020-inch slotted PVC well screen. The screened ' interval of the Zone A wells will be 20 feet in length, extending from approximately 5 feet to 25 feet bgs. The screened interval of the Zone B wells will be 15 feet in length, extending from ' approximately 35 feet to 50 feet bgs. The wells will be completed with Monterey #3 sand filter pack placed within the annulus of the well from the bottom of the boring to approximately 2 foot ' above the top of the well screen, followed by a 2-foot well transition seal consisting of bentonite, and neat cement to ground surface. The newly installed extraction wells will be incorporated ' into the Groundwater Extraction System and the quarterly sampling program for the Site. The wellheads will be completed at the ground surface with locking well caps and traffic-rated ' bolt-down well vaults. Each vault will be installed slightly above the surrounding surface grade and finished with a concrete apron to provide positive relief away from the wellhead. A California-licensed land surveyor will then survey the wellhead elevations with respect to mean sea level (msl) and in accordance with GeoTracker requirements. ' Page 6 of 9