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Califorrua Department of Transportation July 7, 1994 Project No 102818-01 Groundwater monitoring well MW-10 was located in the center of a former tank excavation that was backfil d with gravel The gravel backfill extended to a depth of 20 feet below ground surfaceNeld to dull out the monitoring well were not successful due to r the surrounding gra the approval of San Joaquin County PHSEHD, roundwater monito -10 as abandoned b ressure routin the well fromg YP grouting � ' the bottom to the top with a mixture of neat cement and approximately 5 percent bentonite i grout GROUNDWATER MONITORING WELL LOWERING Groundwater monitoring wells MW-9,MW-11,MW-13,MW-14,MW-lb,MW-19,MW-20,and ' MW-24 were lowered approximately b feet due to proposed future site construction Groundwater moiutoring well lowering consisted of the following activities removal of the ' well cover and box, and conservation forg otential future use, drilling out of the annular seal P to an approximate depth of b feet bgs, severing of the PVC casing at an approximate depth of 5-1/2 feet bgs, placement of a slip cap on top of the PVC casing, backfilling of the hole with clean sand, placement of a small metal object at an approximate depth of 4 feet bgs to + facilitate future well locating, placement of an approximate 1/2-foot bentonite seal near the top of the hole, and placement of approximately one foot of neat cement or soil to match the surrounding round surface �= t STOCKPILE SOIL SAMPLING Soil cuttings generated from abandonment and lowering activities were placed on Visqueen 1 in two separate stockpiles located near the southeast corner of the facility Soil was separated into the stockpiles based on the results of previous soil sampling and analysis ' co t well installation Each stockpile contains approximately 15'� conducted during monitoring p pp y� ' cubic yards of soil A single soil sample was taken from each stockpile Soil sample SP-1 #1 was collected from the c of the northernmost stockpile at an approximate depth of 1/2- foot below the surfa �.� dy1m e SP-2 #1 was collected from the center of the southernmost stockpile at an ap� a of 1/2-foot below the surface Soil samples Teflon- were collected by tightly packing soil i to w e-mouthed, 8-ounce glass jars with Teflon- lined, screw-type lids obtained from the laboratory Samples were then labelled, placed in ! 4 gJfllJf®��®®LP(1�