ARCHIVED REPORTS_SITE INVESTIGATION AND WELL DESTRUCTION PERMIT

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Shell Site Investigation Report groundwater sample collected from well MW-16, which delineates crude oil impact in groundwater east of boring B-109. Section 5.0 Well Destruction Field Activities 5.1 Dates From July 2 through July 19, 2014,Cascade Drilling, LP(Cascade) properly destroyed all groundwater monitoring wells(sans MW-16)and vapor probes. Cascade is a C-57 licensed driller. 5.2 Personnel Present CRA field staff, Bob Siegfried,Jeff Schrupp,and Jason Hills directed the destruction of the monitoring wells and vapor probes under the supervision of California Professional Engineer, Dan Lescure. 5.3 Monitoring Well and Vapor Probe Destruction Refer to Table 1 for listing of the wells and vapor probes that were destroyed. Boring logs for the destroyed wells are included as Appendix I. Permits(Appendix D)were obtained from the San Joaquin County Environmental Health Department(SJCEHD)for well and probe destructions. As specified by the SJCEHD,wells MW-3, MW-6 through MW-12, MW-14B, and MW-14C were destroyed by pressure grouting the well casings using cement grout. The cement grout was placed in the well from the bottom up using a tremie pipe. After the well casing was filled with cement grout, 25 pounds per square inch of air pressure was applied to the well casing for approximately 5 minutes. Once the wells were completely grouted,the well vault boxes were removed,and the surface was restored to match the surrounding grade (graded agriculture field). As specified by the SJCEHD,the remaining wells and vapor probes were destroyed by over-drilling and then the boreholes were grouted from the bottom up using a tremie pipe. Wells MW-SA, MW-513, MW- SC, MW-13B, and MW-13C were over-drilled using an air sonic drilling rig. The other wells and vapor probes were over-drilled using a hollow stem auger rig. Once the wells and vapor probes were completely grouted, the well vault boxes were removed,and the surface was restored to match the surrounding grade(graded agriculture field). 5.4 Waste Disposal Stovepipe well vaults and their concrete bases were the only waste material generated from the field activities. Cascade properly disposed these materials. Over-drill cuttings were stored in a roll-off bin, which was off-hauled on July 2,2014. American Integrated Services, Inc. of Fairfield, California transported the bin to Keller Canyon Landfill in Pittsburg,California for proper disposal based on the waste profile. The waste manifest is included as Appendix H. OW223(35) (/.f. CONESTOGA-ROVERS \t, &ASSOCIATES September2014 6