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Monitoring Well Destruction Report Raymond investment Corporation 730 E.Channel Street Stockton,California Page 3 to commencement of fieldwork, a tailgate safety meeting was held and a site-specific Health and Safety Plan was discussed with,and presented to, all field personnel for their signatures. 4.0 DESTRUCTION OF MONITORING WELLS V & W Drilling of Stockton, CA, a California C-57 driller, license number 720904, performed the destruction of the monitoring wells in accordance with State of California Department of Water Resources (DWR) and SJCEHD requirements. Each monitoring well casing was sounded for water level and total depth prior to destruction. MW-1,MW-3R,and MW-7 were destroyed by pressure grouting with neat cement while leaving the well casing in place. Neat cement was mixed at approximate ration of five gallons of water for each 94-pound bag of cement. The neat cement was placed into the well casing using a truck mounted pump, hose,and tremmie pipe to fill the casing from the bottom upward. PVC pipe fittings and pressurized air fittings were then attached to the well casing. Pressurized air from a truck mounted air pump was then applied to the neat cement in the well casing at 30 pounds per square inch (psi) for 10 minutes to drive additional cement into the sand pack of the well and surrounding soil formation. A two-foot diameter and three feet deep section of soil was removed from around the top of the well casing. The top two and half feet of well casing was removed. Additional neat cement was placed in the well casing and allowed to spill over into the excavated area below where the casing had been cut off and additional cement was added to within one foot of the surface. Sand was added to within seven inches of the surface,after the neat cement had been allowed to set for several hours.The surface was completed with concrete. Groundwater was not displaced to the ground surface. 3 Monitoring wells MW-2, MW-4,MW-4D,MW-5, and MW-6 were destroyed by over-drilling to remove all of the contents of the well including the well casing, screen, cement, bentonite, and sand. The auger used to over-drill the wells was fitted with a casing reamer that kept the augers centered on the casing and i shredded the PVC casing as the augers were advanced. The augers were advanced to a depth of 72 feet in MW-4D and 47 feet in the other monitoring wells. Each borehole was then backfilled with neat cement using a truck mounted pump hose and tremmie pipe to fill the borehole from the bottom upward to one { foot below grade. Sand was added to within seven inches of the surface, after the neat cement had been E allowed to set for several hours. The surface at each location was completed with concrete. Groundwater was not displaced to the ground surface. The soil vapor monitoring wells SV-3, SV-4, and SV-5 were destroyed by over-drilling with a 4-inch hand auger.The borehole was then backfilled with neat cement poured from the surface to within 6 inches below grade with concrete added to surface grade. Bill Cook, a Condor Professional Geologist, observed the well destructions. John Yoakum of SJCEHD inspected the destruction of the monitoring wells. Jason Ender of the City of Stockton inspected the replacement of concrete sidewalk where MW-7 was removed. The soil cuttings, pieces of PVC casing, traffic boxes, and concrete was placed in roll-off containers and left on-site pending disposal. Monitoring well destruction details including depth to water, destruction method; total depth expected, total depth actually encountered, over-drilling auger diameter,total volume of neat cement calculated to be needed to fill the borehole, and total volume of neat cement actually placed are included in Table 1 on the following page. f ` I t is CONDOR