ARCHIVED REPORTS XR0000652 - Laserfiche WebLink

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b Page 4 3. FIELD ACTIVITIES 3.1 MONITOR WELL ABANDONMENT On 5 November 1991, Artesian supervised Gregg Drilling of Concord, California in abandoning monitor wells MW-1 and MW-2 Mr Mike Infurna, San Joaquin County Environmental Health Department, witnessed the well abandonment Gregg Drilling is a licensed C-57 well driller Both wells were in the vicinity of the planned excavation area MW-1 was too close to the open tank pit, so MW-1 was abandoned using a pressure grout from the bottom of the well at 28 feet below ground surface (bgs) to about 8 feet bgs The bentonite grout was forced into the bottom of the polyvinyl chloride (PVC) well casing with a grout pump under pressure Above 8 feet, the well was left open and was broken off by an excavator later during underground tank removal activities Monitor well MW-2 was over-drilled using a ten-inch diameter hollow-stem auger and the borehole was pressure grouted neat cement Water displaced by the grout was contained and collected for disposal in 55 gallon drums with quarterly groundwater sampling purge water The water, 150 gallons, was removed and properly transported under uniform hazardous waste manifest on 26 November, 1991 by Erickson, Inc of Richmond, California The water was disposed of at the Gibson Oil/Pilot Petroleum Facility in Redwood City, California The manifest is included in Appendix D 3.2 SOIL REMEDIATION TANK EXCAVATION AREA Excavation of an additional 612 cubic yards of gasoline contaminated soil in the tank pit was performed on the weekends of 4 and 5 April 1992 and I 1 April 1992 The soil was screened and segregated in the field using a photo-ionization detector(PID) Artesian documented the soil removal process with field reports and photographs After the removal of soil having obvious staining, odor or detectable levels of organic vapors as detected on a PID, confirmatory soil samples in the walls and floor of the excavation were selected at 1