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•i Summary of Well Destruction 2 / Conoco Incorporated-Former Conoco Gas Station 4325 East Washington Street Stockton CA February 4, 1998 of the onsite wells was observed and approved by Mr Harlin Knoll of the SJCEHD The six offsite wells located in the City nght-of-way were pressure grouted to three feet below grade surface (BGS),the well boxes were removed, and the remaining void was filled with aggregate base rock flush with the existing road side gravel Well MW-19 was pressure grouted to 1 foot below grade, the well box was removed, and the void was filled with quick setting cement that was finished flush with the asphalt paving A total of thirty six onsite wells were destroyed by pressure grouting and three wells, BW-1, VW-34, and VW- 35 were over drilled and grouted Each well was filled with grout to two feet BGS, the box removed, and the remaining void filled with aggregate base rock flush with existing grade It was assumed that the two bio monitoring wells, BW-1 and BW-2 were approximately 60 feet BGS While drilling out the casing for BW-1, hard drilling was encountered at 7 feet and the drilling was terminated at 12 feet BGS in native soil The well was then grouted back to 3 feet BGS Prior to destroying BW-2, the depth of the well was measured at 8 feet BGS Mr Harlin Knoll of the SJCEHD approved pressure grouting wells BW-2 and requested that SECOR verify the depth and completion for wells BW-1 and BW-2 to insure the wells were properly destroyed SECOR and Conoco have not been able to located any boring logs or completion history for the wells, MW-1 and BMW-2, however the field information strongly indicates the both wells were completed between 8 and 12 feet BGS and have been properly destroyed Waste Profiling and Disposal All soil, PVC, concrete, and well boxes generated during the well destruction work were placed in a locking 10 cubic yard roll-off bin Approximately 9 cubic yards of sand and soil were generated during the well destruction project Four discrete soil samples SP1-A, SP1-13, SP1-C, and S61-D, were collected at a depth of 18 inches in the stockpile using 6-Inch-long by 2-inch-diameter brass cylindrical sleeves The sample tubes were sealed with teflon pads, plastic caps and tape, labeled, and placed in a cooler on Ice The soil samples transported under chain-of-custody manifest to Quanterra Environmental Services in West Sacramento, California for analysis The four discrete samples were combined in the laboratory in one composite sample, SB1(ABCD), and analyzed for benzene,toluene, ethylbenzene, and total xylenes (BTEX), methyl-tert-butyl-ether (MTBE), total petroleum hydrocarbons-as-gasoline (TPH-G) using EPA method 8020/8015 modified The composite soil sample contained no reportable concentrations of BTEX, MTBE, or TPH-G above the laboratory reporting limit (Attachment 4) The soil profile data was submitted to and accepted by Altamont Landfill for disposal On January 19, 1998, IWM Inc transported 9 cubic yards of well destruction material to the Altomont Landfill located in Livermore, California for proper disposal (Attachment 5) File ProiectlConocolStockton\WeliDestructl LTR