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SOP No. 5.0 Monitoring Well Installation <br />5.2.1.5 Surface Seal Installation <br />Groundwater monitoring wells will be constructed with above- ground completions. A concrete <br />surface seal will be placed around the annulus of the well to a minimum depth of one foot or to <br />the top of the bentonite /cement grout, whichever is deeper. Twenty -four hours should elapse <br />between grout emplacement. and installation of the surface seal to allow the grout to cure and <br />shrink and prevent a•cavity from forming between the two seals. The well casing will be <br />extended 2 to 3 feet above land surface, and a reference point will be marked for future water <br />level measurements on the north side of the casing using a decontaminated metal file. A casing <br />cap for each well will be provided, and the extended casing will be shielded with a protective <br />steel casing that has a locking cap placed over the PVC well casing. The steel casings will be <br />cemented in place and will extend a minimum of 2 feet below ground surface and 3 feet above <br />ground surface. Center the protective steel casing around the monitoring well casing and insert <br />the steel casing approximately 3 feet into the cemented annulus. The protective casings will be a <br />minimum of four to six inches larger in diameter than the PVC monitoring wells. The protective <br />steel casing will be seated in a 1 -foot by 1 -foot by 6 -inch or larger concrete surface pad. The pad <br />will be sloped away from the protective casing: The concrete pad surface will extend <br />approximately one inch aboveground surface with about 5 inches below grade. The well number <br />or identification code will be indelibly marked on the protective casing and on the well cap. A <br />lockable cap or lid will be installed on the protective casing. In high traffic areas near roads or <br />parking areas, the steel protective casing will be protected by four, 4 -inch- diameter, Schedule 40, <br />steel guard posts. The guard posts will be 6 feet in total length, with 3 feet bgs and 3 feet above <br />ground surface. The guard posts will be set in concrete, but will not be installed in the concrete <br />pad placed at the well base (ASTM 1996, EPA 1990). <br />All wells will be secured as soon as possible after drilling. Corrosion- resistant locks will be <br />provided for the steel protective casing. The locks must either have identical keys or be keyed <br />for opening with one master key. <br />5.3 WELL TYPES <br />Four types of monitoring well could potentially be completed from the drill holes and they may <br />be completed in clusters. The wells will be located to most advantageously meet the data quality <br />objectives (DQOs) as determined by the project manager. Type 1 well completions were <br />exclusively used in the Regional Site Characterization Plan. Type 2 -4 well completions are <br />options which could be used during future monitoring activities. The Type 1 well will be a <br />monitoring well completed within the narrowest drill hole available. This well would be <br />completed with 2.0 inch to 4.0 inch PVC casing in a 6 -5/8 inch drill hole or 7 -5/8 inch drill hole. <br />The purpose of the Type 1 well is to collect a subsurface water sample, if water encountered <br />and /or to provide access to the geophysical tools (SOP No. 34, Geophysical Surveys). The Type <br />2 well will be composed of nested monitoring wells completed in a 9 inch diameter drill hole or <br />8 -5/8 inch drill hole. The purpose of the Type 2 well is to obtain subsurface water samples of <br />multiple water - bearing units and to determine if a vertical gradient is present. The Type 3, or <br />wide well, consists of one or more tensiometers set within the larger diameter drill hole. The <br />7/28/08 <br />5 -7 R Incorporated <br />