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` Project No. 014-94276 <br /> Page No. 4 <br /> to pressure grouting, the wells were sounded to ensure no obstructions were present in the wells. No <br /> obstructions were noted, and the total depths of the wells were consistent with those noted on the well <br /> construction logs. Depth to groundwater was approximate'y 64 feet below grade in each of the wells. <br /> On September 19, 1995, monitoring wells MW-1 and MW-2 were pressure grouted using neat <br /> f cement. Prior to grouting, the well vaults were removed, and the well casing was exposed to a depth of <br /> approximately three feet by digging a hole that measured approximately 12 inches in diameter. The well <br /> casings were cut off at a depth of approximately three feet below grade in each well. The neat cement, <br /> in accordance with DWR guidelines, was mixed at a ratio of one 94 pound bag of cement to six gallons <br /> of water. The neat cement was allowed to first free fall to tte bottom of each well in order to displace the <br /> air in the wells prior to applying pressure. After the well casing was full, a grout pump hose was attached <br /> to the well head through which additional grout was pumped into the well under pressure. After pressure <br /> grouting, a mushroom cap of neat cement was placed over the remaining portion of the exposed casing. <br /> Concrete was then placed on top of the neat cement and was brought to within approximately three inches <br /> l <br /> of grade. The remaining portions of the holes were backfilled to grade with asphalt patch, flush with the <br /> parking lot pavement. <br /> Monitoring well MW-6 was destroyed by over-drilling the well using a hollow stem auger on a <br /> truck-mounted drill rig. The total depth of the well, whic was indicated to be 70 feet below grade on <br /> available constructions specification diagrams, - <br /> p g ms, was over-drilled.Ied. Additionally, the well was constructed <br /> I <br /> using 8-inch outside diameter (OD) hollow stem auger. Ov r-drilling of the well was also accomplished <br /> with 8-inch OD hollow stem auger. Destruction of thew 11 was completed by tremming neat cement <br /> j through the hollow stem auger. The neat cement was mixed at a ratio of one 94-pound sack of cement to i <br /> # . <br /> six gallons of water. The neat cement was brought to within approximately three feet of grade in the <br /> former well boring and was then backfilled with native soil <br /> i <br /> .f . <br /> i <br /> I <br /> k <br /> , KRAZAN& ASSOCIATES, INC. . <br /> Of <br /> Ices Serving the Western United States <br /> 9a276.ac <br />