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i <br /> November 4, 1992 <br /> Henning Bros Drilling Co. , Inc. <br /> Page -2- <br /> Police Facility Emergency Well <br /> 4. Saw cut, and remove a 2 foot square section of the concrete <br /> around the top of the well head. Cut and remove the top 2 <br /> feet of well casing. <br /> 5. Backfill from -183 feet to the bottom of the concrete basement <br /> floor with cement-sand grout. <br /> Install a tremie pipe to within 20 feet of the bottom of the <br /> well. Pump cement slurry through the tremie pipe up to the <br /> specified depth in one continuous operation. Remove the <br /> tremie pipe as the cementing operation continues, however, <br /> keep the bottom of the pipe submerged in the slurry throughout <br /> the filling procedure. Let the grout set for at least 12 <br /> hours before beginning the next item of work. Excess grout <br /> required due to settlement shall be installed and paid for by <br /> the Contractor. <br /> The cementing material for the cement grout shall conform to <br /> API Class A cement. The mixture shall be a slurry of cement- <br /> sand grout and be composed of no less than ten (10) 94 lb <br /> sacks of cement per yard with a water to cement ratio of no <br /> more than 5 gal/sack. The cement mixture density shall be no <br /> less than 112 lb/cubic ft. Bentonite, to make the mix more <br /> fluid and reduce shrinkage, may be used to a total of four (4) <br /> percent of the volume of cement. Water used in the cement <br /> shall be clean, potable water. <br /> 6. Pour new concrete, with a cement strength of at least that of <br /> a six-sack mix, into the 2 foot square section and finish to <br /> match that existing. <br /> 7. Replace, in kind, the section of steel grating cut with a new <br /> galvanized section. <br /> 8. Clean the basement floor and other work areas to their <br /> condition prior to the start of work. <br /> It will be the responsibility of the Contractor to perform the work <br /> in a manner as clean as possible. Any water and/or cement spilled <br /> around the well head shall be completely contained and disposed of <br /> in a proper manner. The Contractor shall take extra precaution to <br /> ensure that no flooding of the basement occurs which may result in <br /> damage to Police Facility Equipment. <br />