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0 0 <br /> Monitoring Well Installation Work Plan Summary <br /> Geosyntec Consultants—August 2010 <br /> A total of four monitoring wells (MW-8, MW-9, MW-10, and MW-11) will be installed in the deeper <br /> groundwater (60 to 80 ft bgs) at the former John Taylor Fertilizers facility (the "Site"), located at 1819 <br /> South Argonaut Street in Stockton, California. Proposed locations for the monitoring wells are shown in <br /> the attached figure. Well installation and development procedures are detailed below. The installation of <br /> these wells was approved by the Regional Water Quality Control Board, as indicated in the attached letter <br /> dated 2 July 2010. <br /> Pre-Installation Activities <br /> Prior to monitoring well installation, the existing Site Health and Safety Plan will be updated as needed in <br /> accordance with California OSHA requirements. <br /> Underground Service Alert (USA) will be notified 48-hours in advance of invasive subsurface work, and <br /> a private utility locator has been retained to perform a geophysical survey in the vicinity of each boring <br /> location to identify utilities,pipelines, or other subsurface obstructions. <br /> Well Installation Procedures <br /> Drilling will be performed by Boart-Longyear using sonic technology and using a system of telescoping <br /> drill pipe that continuously cases the boreholes in order to prevent cross-communication between shallow <br /> and deeper water-bearing zones. The borehole will be continuously cored through the shallow <br /> groundwater-bearing zone using a large diameter (8-inch) drilling pipe. Once the drill pipe has been <br /> advanced past the shallow groundwater zone, a medium diameter (7-inch) drill pipe will be used to <br /> continuously core through the outer (large diameter) drill pipe and advance the boring to the target depth <br /> of approximately 70 to 85 ft bgs. If a second sand layer is encountered before the target depth, a small <br /> diameter drill pipe (6-inch) will then be used to complete the well once the medium diameter drill pipe <br /> has been advanced past the second sand layer. Cores will be logged according to the Unified Soil <br /> Classification System (USCS) by the field geologist or engineer, under the supervision of a California <br /> Professional Geologist. <br /> The monitoring wells will be constructed through the center of the drill pipe. All wells will be <br /> constructed using 2-inch diameter Schedule 40 polyvinyl chloride (PVC) casing. The total depth of the <br /> well and the screen intervals will be selected in the field based on observed soil conditions during logging <br /> activities. The screen interval length will be approximately 10 feet long. The well screens will consist of <br /> 2-inch diameter Schedule 40 PVC with a 0.020-inch factory slotted screen and a flush-threaded bottom <br /> cap. After the casings are installed, the annular space between the borehole wall and the well screen will <br />