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0 0 <br /> Section 3 Groundwater Monitoring Well Installation <br /> Filter Pack—A#2/12 Lonestar Sand, or equivalent filter pack will be used. The proposed <br /> monitoring wells are intended for sensitive water quality determinations;therefore all filter pack <br /> material shall be handled to avoid contact with contaminants as discussed in Section 11 of the <br /> California Well Standards. The filter pack will extend two feet above the top of the screened <br /> interval. <br /> Slot Aperture Width—Well screens will be installed with a 0.010-inch slot aperture width. <br /> Protective Surface Casing—Six linear feet of nominal 6-inch diameter Ya-inch wall steel casing, <br /> or 6 x 6-inch square tubing, equipped with a lockable,removable cap will provide the protective <br /> surface casing. This casing will be cemented in place from approximately two feet above ground <br /> surface to a depth offour feet. A 3.5 x 3.5-foot square or 3.5-foot diameter circular, 4-inch thick <br /> concrete pad will be poured surrounding each well. <br /> Well Cap—2-inch diameter expandable, lockable compression plug. <br /> Transition Seal—Two feet of granular bentonite will be placed on top of the filter pack <br /> providing a transitional seal from the filter pack to the sanitary surface seal. <br /> Surface Seal—Site conditions at various well locations warrant the construction of wells with <br /> depths less than 20 feet bgs. In these instances, a surface seal of no less than 4-feet will be used. <br /> Figures 3 and 4 depict the typical monitoring well completion anticipated for these sites. <br /> Special attention shall be given to the construction of the monitoring wells to minimize the <br /> potential for contamination of any materials used in the installation. <br /> 3.6 WELL DEVELOPMENT <br /> The drilling contractor will develop the wells using a combination of methods. Where <br /> practicable and where formations stability permits,well development by gently swabbing the <br /> well with a surge block will be initiated before the installation of the bentonite transitional seal or <br /> neat cement/cement grout sanitary seal to ensure settling of the filter pack prior to sealing the <br /> annulus. Once the seal has been installed and sets up for no less than 12 hours, further <br /> development by vigorously swabbing the well with a surge block and manual bailing will ensue <br /> and continue until the concentration of suspended solids in the water bailed from the well is <br /> sufficiently low to permit pumping with a portable submersible pump. Accumulated fill shall be <br /> removed from the bottom of the well screen. <br /> Development will continue until the discharge water runs clear and/or field measured turbidity is <br /> 5 n.t.u., or less. <br /> Water generated from the wells during development will be discharged directly to land. <br /> May 2006 Main Stone Property <br /> 3-3 Effluent Storage and Disposal Site Hydrogeologic Investigation Workplan <br />