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28 July 1999 AGE-NC Project No 96-0263 Page 7 of 9 Soil cuttings generated during dnlling of the soil borings will be contained within plastic sheeting on the site for storage Drums containing decontamination water and soil cutting will be stored on- site pending appropriate removal, disposal and/or treatment 4 12 Monitoring Well Installation The monitoring well borings will be completed using hollow-stem auger drilling techniques Soil borings will be advanced using a truck-mounted drill rig equipped with hollow-stem augers The pilot boring for ground water monitoring wells will be advanced utilizing 8 25-inch augers Proposed monitoring well designs are illustrated in Figures 4 and 5 Following completion of the shallow soil borings for monitoring wells, a 2-inch diameter Schedule 40 PVC 0 02-inch slotted well screen and casing will be installed A 15-foot section of well screen will be installed from a depth of approximately 5 feet to 20 feet bsg The casing, filter pack and well sealing materials will be placed into the borehole through the interior of the hollow-stem augers After installing the well casing, filter pack material consisting of pre-washed 43 Lonestar sand will ibe added from the bottom of the borehole to approximately two feet above the lower screened interval Following placement of the filter pack, the well will be surged to assist in settling the filter pack Additional sand will be added if settling occurs A nominal one-foot bentonite seal will be placed above the filter pack Bentonite chips will be hydrated be hydrated using five gallons of potable water For the completion of the depth discrete monitoring well, a 2-inch diameter Schedule 40 PVC 0 02-inch slotted well screen and casing will be installed A 5-foot section of well screen will be installed up from the terminal depth of the soil boring This depth will be determine by field screening and observations The casing,filter pack and well sealing materials will also be placed into the borehole through the interior of the hollow-stem augers After installing the well casing, filter pack material consisting of pre-washed #3 Lonestar sand will be added from the bottom of the borehole to approximately one-feet above the depth discrete screened interval Following placement of the filter pack, the well will be surged to assist in settling the filter pack Additional sand will be added if settling occurs A nominal one-foot bentonite seal will be placed above the filter pack The remaining annular spaces will be filled to the ground surface with a cement grout The grout mixture will consist of Type I/H Portland neat cement and not more than 10 gallons of water per 94-pound sack of cement The grout will be placed by pumping through tremmie pipe Grouting Procedures will be inspected by PHS-EHD personnel A traffic-rated well box will be installed over the wells, in accordance with County regulations Following completion of the monitoring wells, well elevations and locations will be surveyed by Advanced CeoEn%ironmental,Inc