SITE INFORMATION AND CORRESPONDENCE

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Appendix A A monitoring well is typically cased with threaded, factory-perforated and blank Schedule 40 PVC. The perforated interval consists of slotted casing, generally with 0.01 or 0.02 inch-wide by 1.5-inch-long slots, with 42 slots per foot. The screened sections of casing are factory machine slotted and will be installed approximately 5 feet above and f 10 feet below first-encountered water level. The screened interval will allow for seasonal fluctuation in water level and for monitoring floating product. A threaded or slip PVC cap is secured to the bottom of the casing. The slip cap can be secured with stainless [ steel screws or friction; no solvents or cements are used. Centering devices may.be E fastened to the casing to ensure even distribution of filter material and grout within the borehole annulus. The well casing is thoroughly washed and/or steam cleaned, or may be purchased as pre-cleaned, prior to completion. A filter pack of graded sand will be placed in the annular space between the PVC casing and the borehole wall. Sand will be added to the borehole through the hollow stem of the augers to provide a uniform filter pack around the casing and to stabilize the borehole. The sand pack will be placed to a maximum of 2 feet above the screens, followed by a minimum 1-foot seal consisting of bentonite pellets. Cement grout containing 5 percent bentonite or concrete will be placed above the bentonite seal to the ground surface. A concrete traffic-rated vault box will be installed over the monitoring well(s). A watertight locking cap will be installed over the top of the well casing. Reference elevations for each monitoring well will be surveyed when more than two wells will be located on site. Monitoring well elevations will be surveyed by Stratus or a subcontractor to the nearest 0.01-foot relative to mean sea level (MSL) or a site datum. Exploratory boring.logs and well construction details will be prepared for the final written report. Vapor Extraction Well Installation The borehole diameter for a vapor extraction well is typically a minimum of four inches larger than the outside diameter of the casing. A vapor extraction well is typically cased with threaded, factory-perforated and blank Schedule 40 PVC. The perforated interval consists of slotted casing, generally with 0.01 or 0.02 inch-wide by 1.5-inch-long slots, with 42 slots per foot. A threaded or slip PVC cap is i secured to the bottom of the casing. The slip cap can be secured with stainless steel screws, friction or PVC cement if the well is not completed into ground water. Centering devices may be fastened to the casing to ensure even distribution of filter material and grout within the borehole annulus. The well casing is thoroughly washed and/or steam cleaned, or may be purchased as pre-cleaned,prior to completion. I E Setting the casing inside the hollow-stem auger, sand or gravel filter pack material is poured into the annular space to fill from boring bottom to generally one foot above the M i