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Geosynte& consultants Of the 10 borings to be installed, one boring will be an exploratory boring and nine (9) borings will be converted into groundwater monitoring wells. The exploratory boring (EBI on Figure 3) and two (2) monitoring well borings (locations B2 and B4 on Figure 5) will be advanced to the bottom of the B-zone aquifer, or a maximum of 140 feet bgs, to collect lithologic data and soil and groundwater chemistry data. Boring installation activities will be completed in accordance with SOP 1.0 (Appendix B). Soil sampling techniques are discussed in greater detail below in Section 4.2.1.1. Once complete, the exploratory boring (EBI) will be destroyed in accordance with SJEHD requirements. The exploratory boring will be destroyed by backfilling, from the bottom of the borehole to the surface, with a cement-bentonite grout slurry using a tremie pipe. Of the remaining nine (9) borings, five (5) will be converted into A-Zone wells and four (4) will be converted into B-Zone wells as discussed below in Section 4.2.2. All borings to be converted into monitoring wells shall have a final diameter equal to the outer diameter of the well casing plus 2-inches on each side. Well construction details are provided below in Section 4.2.2.1. 4.2.1.1 Soil Sampling Soil samples will be collected from differing lithologic layers for both field classification and laboratory analysis. The field geologist will prepare a log for each soil boring. Logs will indicate field classification of soils, sampling depths, progress of drilling, final completion depth, and the nature and resolution of any problems encountered. The soil core from each boring will be described using the visual-manual procedures of American Standard for Testing Materials (ASTM) Standard D 2488 for guidance, which is based on the Unified Soil Classification System (USCS) (Appendix B, SOP 2.0). Select soil samples from each boring will be monitored for organic vapors using a photo-ionization detector (PID). The screening equipment will be calibrated daily against a span gas (e.g., isobutylene) having a concentration of 100 ppm and recorded on each log. The soil samples will be monitored by placing a sample of soil retrieved from the boring into a plastic bag. The soil sample will be broken up in the sealed bag. The PID probe will then be inserted into the bag to monitor the headspace. Select soil samples representative of both the A-Zone and B-Zone aquifers will be collected from the exploratory boring location (location EBI on Figure 3) and the mid- plume well boring locations (locations B2 and B4 on Figure 5). Each soil sample will consist of a combined 24 ounces of soil collected from different lithologies representative of the targeted aquifer zone (i.e. 24 ounces of soil representative of the Pre-Design Investigation Work Plan 17 18.05.12