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Woodward-Clyde <br /> Consultants <br /> Mr. James L. Tjosvold <br /> Project No. 90189N <br /> May 24, 1993 <br /> Page 4 <br /> the well has been determined to be free of obstruction, the decommissioning of the well will <br /> begin. <br /> 2.2 WELL DECONBUSSIONING ACTIVITIES <br /> Each well will be decommissioned by the "tremmie grout" method. The well will be filled <br /> from the bottom up with an impervious material such as neat cement or another approved <br /> material. The grouting operation will take place in one continuous operation. After the <br /> well is filled with grout, head pressure will be applied from the top to ensure that the grout <br /> will flow into all voids. Additional grout will be placed in the well on an as needed basis. <br /> The head pressure will be maintained for a length of time sufficient for the cementing <br /> mixture to set. A verification that the volume of the material placed in the well is at least <br /> equal to the volume of the empty casing and voids will be made. After the cementing <br /> mixture has set, the Christy box will be removed. A hole will be excavated around the well <br /> casing to a depth of 3 feet below the ground surface and the well casing will be cut <br /> approximately 3 feet below the ground surface. Capping of the monitoring wells will be <br /> performed (see below). All activities will be recorded in a field log book. The durations <br /> of the maintained injection pressures for each well will also be recorded. <br /> During periods when no work is being done on the well (overnight or while waiting for the <br /> sealing material to set) the well and surrounding excavation shall be covered. The cover <br /> will be sufficiently strong and well enough anchored to prevent the introduction of foreign <br /> material into the well and to protect the public from a potentially hazardous situation. <br /> 2.2.1 Capping of Wells in Paved Area <br /> The hole (top of well) will be filled with a cementing mixture to depth of approximately <br /> 6 inches below the ground surface. The remaining 6 inches will be filled with a material <br /> (asphalt or concrete) similar to that surrounding the well head. <br /> 2.2.2 Capping of Wells in Unpaved Areas <br /> The hole (top of well) will be filled with a cementing mixture to a depth approximately <br /> 2.5 feet below the ground surface. The hole will then be filled with native soil. <br /> 90189N/LUCA2/05-24-93 SAC <br />