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A back-up plan to destroy these 1-inch-diameter wells will include pressure grouting the wells followed by overdrilling each well to total depth using a hollow-stem auger drilling rig equipped with 15-inch-diameter augers. Once advanced to the total depth of each well, 8-inch-diameter hollow-stem augers will be advanced within the annulus of the 15-inch-diameter augers to total depth destroying the PVC casing. The 8-inch-diameter augers will then be removed and grout introduced through the annulus of the 15-inch-diameter augers with a tremie pipe, if required by the SJCEHD grout inspector, from the total depth of each boring to a depth of approximately 5 feet. The remaining 5 feet of annulus will be backfilled with either grout, sand, or native soil obtained from the overdrilling. The top approximately 6 inches of each boring will be backfilled with either native soil or concrete dyed black (as needed)to blend in with the surrounding ground surface. Overdrillina %-Inch-Diameter Nylon Tubina Wells Usina a Hollow-Stem Auger Drilling Ria and a Hand Auaer Wells SV-2 and SV-3 will be destroyed by drilling out the casing and annulus to the total depth of each well using a hollow-stem auger drilling rig. Drilling rods will be advanced through the center of the grout column to the total depth of the wells followed by the advancement of 8-inch-diameter hollow-stem augers around the rods thereby ensuring the augers stay centered on the wells. These wells are constructed of '/4-inch-diameter nylon tubing and extend to depths of 6 feet. Grout will be introduced through the annulus of the augers with a tremie pipe, if required by the SJCEHD grout inspector, from the total depth of each boring to a depth of approximately 0.5 foot. The top approximately 6 inches of each boring will be backfilled with concrete and dyed black at the surface (as needed)to blend in with the surrounding asphalt. Due to the sensitive location of well SV-1 in a landscaped area behind shrubs and beneath a low overhang of the Chase Bank, the well is inaccessible even with a limited-access rig. Therefore, well SV-1 will be destroyed by using a jack hammer to remove the well box and top foot of concrete from the well. Hand-augers will then be advanced to the total depth of the well, removing well materials as the hand- augers are advanced. Since well SV-1 was installed with an 8-inch-diameter borehole, the approximately 4-inch-diameter hand-auger will be advanced multiple times to ensure all well materials are removed. Grout will be introduced with a tremie pipe extending to the bottom of the boring and will be added from the total depth of the well to a depth of approximately 0.5 foot. The top approximately 6 inches will be backfilled with clean native soil to blend in with the surrounding ground surface. Overdrilling Using Sonic Drilling Ria Remediation wells SP-lA, SP-113, SP-2, SP-3, SP-4, SP-5, SP-6, SP-7 and SP-8 will be destroyed by overdrilling the casing and annulus to the total depth of each well using a sonic drilling rig. The diameter of the sonic drilling rods used to overdrill each well will be approximately 4 inches, which is three times larger than the 1.25-inch direct-push rods that were used to install these wells. These wells are constructed of 0.25-inch-diameter Teflon tubing and range in depth from 20 to 65 feet. Grout will be introduced with a tremie pipe extending to the bottom of each boring and will be added from the total depth of each boring to a depth of approximately 5 feet. The remaining 5 feet of annulus will be backfilled with either grout, sand, or native soil obtained from the overdrilling. The top approximately 6 inches of each boring will be backfilled with concrete and dyed black at the surface (as needed)to blend in with the surrounding asphalt. If the use of the sonic drilling rig is deemed unsuitable, a hollow-stem auger drilling rig equipped with either 5.5- or 8-inch-diameter augers will be used to destroy these wells to their total depths following the procedures to destroy 2-inch and 4-inch wells(see pages 1 and 2). Project No.S9482-06-02 -3- January 5,2012