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Extraction Well Installation Summary Report and Injection ARCADIS Well Installation Work Plan Former Occidental Chemical Corporation Facility Lathrop, California be continuously logged, and the lithology encountered will be recorded using the Unified Soil Classification System by an ARCADIS field geologist.After the boring has been advanced to approximately 205 feet bgs, the well will be constructed using a 6-inch-diameter PVC sump,0.020 slot wire-wrapped stainless steel screens,and blank Schedule 80 PVC casing. INJ-14 will be screened from approximately 95 to 150 feet bgs and from 170 to 200 feet bgs. The proposed location of INJ-14 is shown on Figures 2 and 3. 4.2.1 Filter Pack Installation and Grouting After the screens and blank casing have been placed inside the open borehole, the well annulus materials will be added by pumping the materials through a tremie pipe. The well annulus in the screened intervals will be filled with number 3 sand to a minimum of 2 feet above the screen.A minimum of 3 feet of number 0/30 fine transition sand will be placed above the filter pack sand to prevent the entrance of grout into the filter pack.After the fine transition sand has been placed above the first screened interval, approximately 10 feet of neat cement grout will be placed between the screens.After the grout has had sufficient time to cure, number 3 sand will be placed to approximately 2 feet above the upper screen followed by approximately 3 feet of number 0/30 fine transition sand. Neat cement grout will then be placed in the borehole above the transition sand to the ground surface to seal the remainder of the borehole. Proposed well construction details are shown on Figure 4 and may be modified based on field conditions. 4.2.2 Well Development INJ-14 will be developed using one or more of the following methods: air development,water jetting, and mechanical surging. Grout will be allowed to cure for a minimum of 48 hours before development activities are conducted. The specific methods and duration of well development will be determined in the field based on professional judgment.Water quality parameters, including pH, conductivity, and turbidity, will be monitored to track and document progress during development. 4.3 Well Survey and Sampling The top of casing elevation and coordinates will be surveyed by a California licensed land surveyor. A groundwater sample will be collected upon completion of the well installation and development activities prior to initiating injection. Collected groundwater samples will be submitted to APPL and analyzed for the following constituents: • Sulfolane according to by APPL 3510/SOP ANASULF using a gas chromatograph/mass spectrometer lathmp well mstellaton repos.final(0x2913)docx 10