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• • RESOURCE <br /> `i HYDROGEOLOGIC <br /> SERVICES <br /> is 6-3/8-inches. If applicable, all drilling discharge water shall be discharged to the ground or a <br /> small infiltration pit as the site conditions warrant. <br /> 2. Hang in tension from appropriate threaded installation plug or clamp 2-inch schedule 40 PVC <br /> environmental flush joint screen (0.010-inch factory-machined slot) from total depth to near <br /> ground surface as determined by the RHS hydrogeologist. Blank flush joint 2-inch schedule 40 <br /> PVC shall extend from the top of screen section to 2-1/2 feet above ground surface. Stainless <br /> steel bow spring environmental centralizers shall be placed at the bottom and top of the screen <br /> section. All tubulars and centralizers shall arrive to site new, bagged and boxed. <br /> 3. Complete by 20-40 silica sand pack from total depth to 1-2 feet (typical) above the top of screen <br /> section via surface pour, with continuous depth tagging to the level specified by the RHS <br /> hydrogeologist. Bentonite seal shall be accomplished by pouring one 5-gallon pail of %-inch or <br /> 3/8-inch coated bentonite pellets via surface pour, hydrating with potable water as necessary if <br /> the hole is not holding water at this depth. The remaining annular seal up to ground surface, if <br /> necessary,shall be placed by pouring 3/8-inch chip bentonite from surface, hydrating with potable <br /> water as necessary. Continuous depth tagging shall be employed to ensure materials bridging <br /> does not occur. <br /> 4. Install appropriate 5-foot length by 4-inch square or round locking environmental monitoring well <br /> head protector set in 3-foot by 3-foot by 4-inch-thick cement pad with 4-inch diameter by 6-foot <br /> length steel pipe protective bollards cemented in-place offset at each pad corner. The wellhead <br /> shall be clearly labeled by the well name welded either on the top cap or below the locking hasp <br /> prior to arriving onsite. The well name is MW-15. <br /> MONITORING WELL DEVELOPMENT <br /> For wells where groundwater presents in the completed well,well development will be conducted by RHS <br /> no sooner than 24 hours following curing of annular bentonite seals and surface cement pad. However, <br /> the most likely wait period will be on the order of one to two weeks following well installation as <br /> experience with MW-8 installation has indicated days to weeks are required for groundwater to present <br /> in newly constructed Fort Hayes and Codell monitoring wells. These developments may be batched as <br /> appropriate to minimize mobilization/standby time. Standard monitoring well development procedures <br /> shall be followed utilizing nominal 2-inch surge block with foot valve driven by an inertial pump (Waterra <br /> Hydrolift II) on new HDPE tubing to remove fines and properly distribute the annular filter pack. A new <br /> disposable bailer and cord may be used in conjunction with this method depending on the well production <br /> rate. Water quality field parameters shall be monitored by the RHS field hydrogeologist during this <br /> process with emphasis in monitoring and reduction of turbidity over time as fines generated during the <br /> drilling process are removed through the wellbore. It is generally expected that well development <br /> operations may take on the order of one continuous hour surging per 5-foot screen length, but <br /> GCC Rio GRANDE,INC.PUEBLO PLANT <br /> 2021 MONITORING WELL INSTALLATION PROGRAM WORK PLAN <br /> 8 <br />