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o CONESTOGA-ROVERS &ASSOCIATES Site Safety Plan: CRA will prepare a site safety plan for field work. Utility Clearance: CRA will mark the proposed drilling locations and the locations will be cleared through Underground Service Alert and a private utility locating service prior to drilling. Site Investigation: Four monitoring wells (MW-8 through MW-11) are proposed at the locations shown on Figure 2. The exploratory borings will be drilled using hollow stem auger drilling equipment and will be converted to groundwater monitoring wells. Well MW-11 will be completed as a deep groundwater monitoring well to further assess the vertical extent of impacted groundwater. A CRA geologist will supervise the drilling and describe encountered soils using the Unified Soil Classification System. CRA will collect soil samples from borings MW-8 through MW-11 at 5-foot intervals for soil description,possible chemical analyses, and organic vapor screening with a photo-ionization detector (PID). However, beginning at approximately 40 fbg in boring MW-11, soil samples will collected continuously to assist in determining the proper screen interval. CRA will prepare an exploratory boring log for each boring and will record PID measurements on the boring logs. CRA will retain soil samples designated for chemical analyses in stainless steel or brass sample tubes. CRA will cover the tubes on both ends with Teflon sheets and plastic end caps, label the soil samples, enter them onto a chain-of-custody record, and place them into a cooler with ice for transport to a State of California certified laboratory for analyses. We will request a standard 2-week tum-around time for laboratory results. Monitoring Well Installation: Wells MW-8 through MW-10 will be constructed using 2-inch diameter Schedule 40 PVC casing and will be screened from approximately 5 feet above to 10 feet below first encountered groundwater. Well MW-11 will be constructed using 2 or 4-inch diameter Schedule 40 PVC casing and will be screened from approximately 48 to 53 fbg. This target screen interval is based on the groundwater sample collected at 52 fbg in boring SB-1 and the adjacent 7-11 site's deep well MW-6D which is screen from 46 to 51 fbg. An 8 or 10-inch diameter steel conductor casing will be installed in boring MW-11 to prevent shallow groundwater mixing with deeper groundwater during drilling activities. The conductor casing will be set at a depth of approximately 30 fbg. The conductor casing will be sealed with grout and the grout seal will be allowed to set for 48 hours prior to completing MW-11 well installation activities. The sandpack in each well will be placed from the bottom of the well 1661 4 Worldwide Engineering, Environmental,Construction,and IT Services