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29 December 1999 <br /> AGE-NC Project No 98-0465 <br /> Page 7 of 9 <br /> water after washing with a solution of Alconox All hollow stem augers will be steam-cleaned prior <br /> to advancement of each borehole <br /> 43 WELL COMPLETION <br /> Soil borings will be single-completed as ground water monitoring wells utilizing 2-mch diameter <br /> schedule 40 polyvinylchlonde (PVC) 0 020-inch slotted well screen and blank well casing Based <br /> on geologic/hydrogeologic conditions, a 20-foot length of well screen is anticipated for installation <br /> of monitoring wells, the bottom of the screen interval will be placed 15 feet below the water table <br /> A proposed well construction diagram is depicted in Figure 3 <br /> After installing the well casing, filter pack material consisting of pre-washed 43 Lonestar sand will <br /> be added from the bottom of the borehole to approximately two feet above the screened interval <br /> Following placement of the filter pack, the well will be surged to assist in settling the filter pack <br /> Additional sand will be added if settling occurs <br /> . A nominal two-foot bentonite seal (bentonite chips) will be placed above the filter pack to minimize <br /> the potential for grout penetration into the screened section of the well The bentonite seal will be <br /> forined by pouring bentonite chips into the annulus and allowing them to settle on the filter pack <br /> Bentonite chips will be hydrated using approximately five gallons of tap water The bentonite chips <br /> will be allowed to hydrate for a minimum of one-half hour prior to grouting <br /> The remaining annular space will be filled to the ground surface with a cement grout The grout <br /> mixture will consist of Type PH portland neat cement and not more than 6 gallons of water per 94- <br /> pound sack of cement The grout will be placed by pumping through tremmie pipe A grouting <br /> inspection will be scheduled with PHS-EHD personnel <br /> 4 4 WELL DEVELOPMENT <br /> Development of the proposed wells will consist of a combination of bailing with a stainless steel <br /> bailer to remove the mayor portion of fine-grained sediment from inside the well, surging to flush <br /> out or draw in sediment from the filter pack and additional ground water evacuation (purging) with <br /> a submersible pump to finish the removal of fine-grained sediment Developmental purging activities <br /> will be continued until field parameter(pH, electrical conductivity, and temperature) readings have <br /> stabilized and purged water is visually sediment-free <br /> Advanced GeoEnvtronmental,Inc <br />