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DOULOS ENVIRONMENTAL COMPANY 1537 PINE VALLEY CIRCLE ROSEVILLE, CA 95661 (916) 782-9054 November 30, 1998 Mr. Joseph Aldridge Ultramar, Inc. 525 West Third Street Hanford, California 93230 Subject: Well Abandonment Report for Beacon#492 470 North Main Street, Manteca, California i Dear Mr. Aldridge: Ultramar, Inc. (Ultramar), has contracted Doulos Environmental Company (Doulos) to abandon monitoring wells, as well as prepare this report for the subject site. The purpose of this work was to properly abandon the monitoring wells prior to underground storage tank removal and replacement. FIELD WORK I The work performed included: Obtaining a well abandonment permit from San Jaoquin County (permit enclosed), abandonment of seven monitoring wells, and preparing a report which presents field procedures and volumes of grout used. All activities were completed in compliance with the San Joaquin County guideline and California State Department'of Water Resources Bulletin 74- 81. Pressure Grouting On November 2, 1998, Doulos personnel abandoned seven monitoring wells, (MW-1, MW-2, MW-3, VW-1, VW-2, VW-3, and VW-4). Monitoring well MW-4 was not abandoned because it was not iri the area of the tank excavation. Prior to pressure grouting the wells, the volume of grout needed to displace the pore space in the sand pack, and the volume of the casing was calculated. The wells were abandoned in place by pressure grouting with a neat cement slurry. The grout was placed with a trimmie pipe from approximately five feet above the bottom of the well to the surface. Sections of trimmie pipe were removed as the grout moved up the casing of the well. After the grout had been trimmied to the surface additional grout was added to maintain the grout level at the top of the casing as it pushed its way into the sand pack pore space and formation. The actual volume of grout placed in each well exceeded the calculated volume(see Table).