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,law, N%.01 mom CCMWE0 Mr. Jeffrey Brown March 11, 2003 MAR 13 2003 Page 2 ENVIRONMENT HEALTH PERMIT/SERVICES GeoTrans also contracted a private utility locator to survey each well area for potential underground utility conflicts. No utility conflicts were identified. Well Abandonment Wells MW-4, MW-5 and MW-6 were abandoned on February 24, 2003. Mr. Jeffrey Wong of the SJCEHD was on-site to observe the well abandonment work. Each well was 4-inch diameter PVC, with the top of casing set 0.5 feet below grade. Total well depths for MW-4, MW-5 and MW-6 were 35 feet, 45 feet and 45 feet below grade, respectively. Cascade Drilling of Rancho Cordova, California performed the well abandonment work, under the direction of a GeoTrans field geologist. Wells MW-6, MW-5 and MW-4 were abandoned in that order. Prior to beginning work at MW-6, appropriate traffic control measures were set up to divert traffic around the MW-6 work area. Well MW-6 was over drilled to 45 feet and the well string removed. Approximately 18 cubic feet of pulverized cement grout, soil and filter sand was brought to the surface. The material was placed in a large pothole in the dirt turnout near the well. The resulting borehole was back grouted with approximately 110 gallons of neat cement through the augers to approximately 0.5 feet below grade. The grout was placed downhole in one continuous operation as the augers were retracted. The 8-inch diameter well vault box and surrounding 18" x 18" concrete pad were broken out, and the surface completed with 0.5 feet of rapid set concrete, finished flush to grade. The concrete was dyed black to match the surrounding asphalt road surface. Due to the close proximity of overhead power lines to wells MW-4 and MW-5, these wells were pressure grouted. Mr. Wong concurred that pressure grouting wells MW-4 and MW-5 was acceptable due to the safety concerns posed by the overhead power lines. Prior to grouting, each vault box was broken out and soil was excavated from around each well casing to approximately 3 feet in depth, with a one-foot radius around the casing. Approximately 50-gallons of neat cement grout was used in well MW-5 and approximately 40 gallons of grout was used in well MW-4. The volume of neat cement used for each well assures that the well casings and sand filter pack around the screened intervals was sufficiently grouted. The grout was pumped down each well casing via a 1-inch PVC tremmie pipe until the casing was full. Pressure was then applied to the cement in each well string through a PVC pipe assembly connected to the drill rig's compressor via an air hose. Approximately 20 pounds per square inch of pressure was applied GeoTrans,