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% .d s <br /> MNiyERS Cf51GHEN5ff1N51A70.47$ r <br /> `-' 3.0 WORK PLAN <br /> .� 3.1 GENERAL REQUIREMENTS <br /> This work pian has been developed to conform to the Tri-Regional Recommendations and <br /> V <br /> address the concerns of the EHD. All work will be conducted under the direction of a <br /> California Registered Geologist. A bound field log book will be kept for the project. All field <br /> related activities will be documented in the log book. <br /> �. 3.2 MONITOR WELL INSTALLATION <br /> Two monitor wells will be installed at the site (see Figure 6). One well will be located <br /> immediately downgradient of the Tank 3 excavation and one well will be located immediately <br /> downgradient of the Tank 4 excavation. The well locations are based on the groundwater flow <br /> direction calculated from August 1994 and March 1995 quarterly groundwater elevation data. <br /> ,r The monitor wells will be installed in boreholes drilled with a hollow stem auger drill rig. The <br /> monitor wells will be constructed with 2-inch diameter Schedule 40 PVC casing with a 20-ft <br /> 0.02 inch slot screen. The top of the screen will be located at least 3 ft above the groundwater <br /> table. A sand pack (Lonestar IC or equivalent sand) will be placed from 2 ft above the top of <br /> the screen to the bottom of the screen. A 2-foot bentonite seal will be placed above the sand <br /> pack. The remaining annular space will be grouted to the surface with a five percent <br /> bentonite/cement grout. Each monitor well will be completed with a flush mount traffic vault <br /> �. equipped with a locking cap. No less than 48 hours after construction, each monitor well will <br /> be developed by bailing, surging, and swabbing until the water is relatively free of sediment. <br /> The elevation of the top of the well casing will be surveyed so that groundwater gradients can <br /> be calculated. <br /> Soil samples will be collected from the monitor well borings at 5 ft intervals starting at 10 ft <br /> below bgs for lithologic logging and field screening with a photoionization detector (PID). If <br /> �. field screening indicates that soil contains volatile organic compounds, a maximum of 3 soil <br /> samples per boring will be submitted for TPHe and BTEX analysis. Samples will be selected <br /> for chemical analysis based on field screening results, lithologies encountered, and depth to <br /> water. However, based on the results of previous sampling activities conducted at the site, <br /> contamination is not expected. <br /> L\PROJECTS\SANJOQ%MVCWM.WP 6 12 May 1995 <br /> it <br />