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Geosyntec <br /> consultants <br /> Well construction details will be proposed in the Task 2 letter report; however, the <br /> following general procedures will be followed in constructing the monitoring wells. <br /> After reaching total depth in each boring, well construction materials will be placed <br /> through the center of the augers. Well casing will consist of 2-inch diameter threaded- <br /> joint Schedule 40 PVC. Well screen will consist of the same PVC pipe with 0.01-inch <br /> slots. The bottom caps on each well will be threaded. The tops of the well casings will <br /> be fitted with expandable-gasket lockable caps. <br /> After installing the casing and screen, an appropriate sand filter pack will be placed to <br /> about 2 feet above the top of the well screen. As the sand is added, the augers will be <br /> pulled up to allow the sand pack to fill the borehole annulus. A bentonite seal <br /> consisting of about 2 feet of compressed bentonite pellets will be placed above the sand <br /> pack. The pellets will be allowed to hydrate before grouting. <br /> Cement and bentonite grout will be used to seal the borehole annulus from the top of the <br /> bentonite seal to the ground.surface. The grout mix will consist of Type I/Il Portland <br /> cement, bentonite powder,and potable water. The grout will be tremmied into place. <br /> The wells will be completed at the surface with flush mount well boxes or with an <br /> above ground locking well cover and guard posts. Locking well caps and locks will be <br /> installed on all wells. Site personnel will be consulted about whether completions need <br /> to be at-grade or above ground. <br /> 2.3.3 Surveying <br /> The north side of each well box and PVC well casing will be surveyed for elevation and <br /> location by a. licensed surveyor. This information will be used to develop a <br /> groundwater elevation contour map from which the groundwater flow direction beneath <br /> the Site can be inferred. The wells will be surveyed to North American Datum (NAD) <br /> 83 and North American Vertical Datum (NAVD) 88, in accordance with the RWQCB <br /> GeoTracker database reporting requirements. <br /> 2.3.4 Well Development <br /> The new monitoring wells will be developed a minimum of 48 hours after installation. <br /> The purpose of well development is to stabilize the filter pack and remove fines from <br /> the filter pack and well screen. Development will be completed according to the <br /> following general procedures: <br /> Final Work Plan.doc 11 27 June 2012 <br />