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• • <br /> • No geophysical logging will be conducted in this borehole. <br /> • After soil characterization, all soil cuttings will be dumped into and contained in a <br /> 20-yard roll-off bin lined with visqueen. The roll-off bin will be temporarily <br /> stationed near the drilling area. <br /> • The depth interval for the well screen will be based on the lithology characterized <br /> from the continuous core. If necessary, the bottom of the borehole may be <br /> backfilled with Monterey No. 3 sand to the desired depth of the borehole. <br /> 4.4.Well Construction for Well MW-402 <br /> • The construction of well MW-402 will include 10 feet of 2-inch nominal pipe size <br /> Schedule 40 PVC casing perforated with 0.020-inch slots (Figure 2). <br /> • The screen will be set across the shallow zone, which will be identified from the <br /> soil cuttings retrieved during drilling. The shallow zone is characterized as silt <br /> and clay interbedded with some sandy silt and silty sand. The target depth <br /> interval for the screen is approximately 65 ft bgs to 75 ft bgs. <br /> • The bottom of the casing will be capped with approximately 5 feet of 2-inch <br /> diameter Schedule 40 PVC blank casing to act as a sump. <br /> • The remaining length of the well casing will be constructed with 2-inch diameter <br /> Schedule 40 PVC blank casing. <br /> • The filter pack will consist of Monterey No. 3 sand or an equivalent 8x20 sand. <br /> The filter pack will fill the annular space from the bottom of the borehole to 5 feet <br /> above the top of the screen. The filter pack will be gravity fed through a 1.5-inch <br /> diameter tremie pipe or pumped into the borehole. <br /> • The depth of the top of the filter pack will be measured continuously as it is added <br /> to the annular space. The depth of the top of the filter pack will also be compared <br /> to the estimated volume of filter pack needed to fill the annular space to that <br /> depth. <br /> • The screen of well MW-402 will be surged after the filter pack is placed to <br /> collapse any potential bridging of the filter pack during installation. <br /> • Five feet of fine mortar sand (#60 sand or equivalent 40x 100 sand) will be set as a <br /> transition seal between the Monterey#3 filter pack and annular seal. The fine <br /> mortar sand will be gravity fed through a 1.5-inch diameter tremie pipe or <br /> pumped into the borehole. <br /> • Ten feet of time release bentonite pellets will be set at the top of the transition <br /> sand. <br /> • Forty feet of a bentonite neat cement grout with 3% to 5% bentonite will be used <br /> to fill the annular space from the top of the time release bentonite pellets to <br /> approximately five feet below land surface. The bentonite neat cement grout will <br /> be pumped into the annulus through a 1.5-inch diameter tremie pipe. The tremie <br /> pipe will be installed within 5 feet of the desired seal depth and removed as the <br /> grout is installed. <br /> • A Class A Concrete surface seal will be pumped into the annulus from 5 ft bgs to <br /> land surface through a 1.5-inch diameter tremie pipe. <br /> • A 12-inch traffic rated flush-mounted well vault will be installed to protect and <br /> secure the well. <br /> Work Plan—Installation of Monitor Wells 9672 <br /> SPX Corporation 4 Dudek <br /> Stockton,California May 2016 <br />