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r� rrl 23 April 2002 AGE-NC Project No 95-0142 Page 11 of 16 Occupational Safety and Health,Occupational Safety and Health Administration,U S Coast Guard and U S Environmental Protection Agency, October 1985 • Notify the EHD a minimum of 48 hours prior to commencement of any work,while securing proper county soil boring or well permits and city building permits • All drilling locations will be marked at least 48 hours in advance for an Underground Service Alert (USA) check of underground utilities or pipes 42 PILOT SOIL BORING Four pilot soil borings will be advanced at the site to a depth of 60 feet bsg utilizing a truck-mounted hollow-stem drill rig The pilot soil boring will be established with 12-inch diameter hollow-stem augers for the ground water extraction well construction Cuttings generated during drilling will be placed in DOT-approved 55-gallon drums Rinseate will be containerized in properly labeled DOT- approved 55-gallon drums, and stored on-site in an area lacking public access 4 3 WELL COMPLETION The 12-inch diameter pilot soil borings will be single-completed as ground water extraction wells utilizing 6-inch diameter schedule 40 PVC 0 020-inch slotted well screen and blank well casing A 30-foot length well screen is anticipated for installation of the recovery wells Aproposed extraction well construction diagram is depicted in Figure 5 After installing the well casing in each pilot boring,filter pack material consisting of pre-washed#3 Lonestar sand will be added through the augers over the screen interval to approximately two feet above the screened interval Following placement of the filter pack,the well will be surged to assist in settling the filter pack Additional filter pack material will be added if settling occurs A nominal two-foot bentonite seal(pell plug-coded bentonite pellets)will be placed above the filter pack to minimize the potential for grout penetration into the screened section of the well The bentonite seal will be formed by pouring bentonite pellets into the annulus and allowing them to settle on the filter pack The bentonite pellets will be allowed to hydrate for a minimum of one-half hour prior to grouting The remaining annular space will be filled to within one foot of the ground surface with a cement grout The grout mixture will consist of Type VII portland neat cement and not more than 6 gallons of water per 94-pound sack of cement The grout will be placed by pumping through a tremmie pipe Advanced GeoEnvironmental,Inc