Laserfiche WebLink
1 <br /> (716 <br /> i <br /> Mr. Jeff Hennings <br /> Hennings Brothers Drilling Company, Inc. <br /> September 28, 1490 i. <br /> Page 2 <br /> Step 1 <br /> The well casing Shall be filled to a depth of 46 feet bgl (approximately 5 feet below the <br /> bottom of the Nestle 13-lone and 8 feet above the top of the next lower permeable zone) using sand- <br /> cement-bentonite grout. The grout shall be pumped from the bottom of the well casing upward using <br /> a tremie pipe. The bottom of the tremie pipe shall remain near the bottom of the well during the <br /> grouting operation. <br /> The sand-cement-bentonite grout shall be composed of the following mixture: 2 parts sand to <br /> 1 part cement to 5 percent (by weight of cement) powdered bentonite that is mixed with not more <br /> than 7 gallons of water per sack of cement. Approximately 97 cubic feet (3.6 cubic yards) of grout <br /> will be required. t <br /> i <br /> aG <br /> Step 2 shall commence after a minimum waiting period of 48 hours following completion of <br /> Step 1. The well casing shall be perforated using a Mills Knife perforator between depths of 20 and <br /> 46 feet bgL A hole at least 28 inches in diameter shall be excavated around the outside of the well <br /> casing to a depth of 3 feet bgl. The soil removed from this excavation shall be stockpiled for later <br /> use in backfilling the excavation. The well casing shall then be cut off 6 inches above the bottom of <br /> this excavation and removed.. <br /> The well casing shall be filled by pressure grouting using a neat cement-bentonite grout. The <br /> grouting pressure shall be at least 57 pounds per square inch (psi). After completing the pressure <br /> grouting, the additional groui shall be used to: fill the top of the well; spill over into the excavation; <br /> and fill the excavation fora thickness of 1 foot and form a cap which has a diameter of at least 28 <br /> inches in diameter. This procedure should result in the exposed edge of the casing being covered <br /> with 6 inches of grout. <br /> The neat cement-bentonite grout shall be composed of the following mixture: 1 sack of <br /> cement to 5 percent (by weight) powdered bentonite that is mixed with not more than 7 gallons of <br /> water per sack of cement. Approximately 64 cubic feet (2.4 cubic yards)of grout will be required <br /> to fill the well casing and excavation, plus an additional amount that will be pushed into the native <br /> deposits opposite the perforated casing interval. <br /> I <br /> After the grout has set, the excavation shall be filled with soil. <br /> i <br />