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A well construction summary for all probes is provided in Table 1 <br /> 3.6 Landfill Gas Extraction Well Installation <br /> Four LFG extraction wells were installed in LF-1 (GX-10, GX-11, GX-12, and GX-13) <br /> in accordance with the approved EFS. These 4 wells target areas where potential LFG is <br /> potentially affecting groundwater. The 4 wells consist of 2 LFG extraction wells (GX- <br /> 10 and GX-11) near MW-3 and 2 LFG extraction wells (GX-12 and GX-13) installed in <br /> the over-liner section between Module "I" and Module M-1. The purpose of these <br /> extraction wells is to provide enhanced vacuum within the refuse mass in close proximity <br /> to MW-3 and below the overlying impermeable liner believed to be trapping LFG and <br /> promoting migration vertically downward toward groundwater. The locations of all LFG <br /> extraction wells are shown on Figure 3. The installation logs and construction details for <br /> all new LFG extraction wells are contained in Appendix C. <br /> In addition, 4 LFG wells were installed in Module M-1 (GX-14, GX-15, GX-16, and <br /> GX-17) by the County to assist in LFG extraction for energy generation. <br /> 3.7 Survey Data <br /> The probes and wells were surveyed by F3 & Associates a California Licensed Surveyor <br /> on August 31, 2016. Northing, Easting, top of casing elevation, and ground surface <br /> elevations are contained on the well logs. Survey data is contained on Table 2. <br /> 4.0 SOIL GAS MONITORINGACTIVITIES <br /> Field sampling activities were conducted by SCS Engineers (SCS) on August 22, 2016. <br /> SCS collected soil gas data from existing single-level probes SG-1, SG-4, SG-5, SG-7, <br /> SG-8, SG-9, and SG-10. They also collected soil gas data from new tri-level probes SG- <br /> 2A, SG-3A, SG-6A, SG-10A, and SG-1 IA. <br /> 4.1 Soil Gas Monitoring Well Sampling <br /> A vacuum pump was used to purge the SG probes prior to sampling. Soil gas samples <br /> were then collected using the summa canister for TO-15 analysis. TO-15 samples were <br /> collected from existing single-level probes SG-1, SG-4, SG-5, SG-7, SG-8, SG-9, and <br /> SG-10; and from the deepest probe (D) of tri-level SG-2A, SG-3A, SG-6A, and SG-11A. <br /> Following collection, the summa canisters were labeled and sent to the laboratory. In <br /> addition, a Landtec GEM 5000 LFG analyzer was used to measure barometric pressure, <br /> static pressure, percent methane, carbon dioxide, oxygen, and balance gases. <br /> 4 <br />