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i Work Plan - Monitoring Well Abandonment Page 3 Former Western Lift/ Cutter Lumber Site 2, Stockton, CA GPE Project No. 102.3 9 August 2013 2.1 Preparatory Work Prior to commencing field work, a permit to abandon the wells will be obtained from the San Joaquin County Environmental Heath Department (SJC-EHD). All well work will be conducted by V&W Drilling, a C-57 licensed water well contrator. 2.2 Pressure Grouting The following steps will be performed to complete the well abandonment. • The well box lids, locks, caps and dedicated tubing will be removed from each well. • The upper three feet of each well, including the pavement, and well box will be over drilled with a 24 inch diameter coring auger. • Class I/II neat cement will be prepared for use as the grouting agent. • Each well will be.sequentially fitted with a 2 or 4-inch pressure cap as appropriate. Neat cement will then be pumped into each well using a pneumatically actuated cement pump. Pumping will continue until a positive pressure of about 25 pounds per square inch is reached at each well head. The volume of grout pumped will be monitored to verify that the casing is full and the grout has squeezed through the slots and into the gravel pack. The volume of cement pumped into the wells will be monitored to assure" that the materieal has been forced out of the casing and into the supporting gravel pack. • After pressure grouting, the casing will cut off, and a short casing stub of about 6 inches will be left above the bottom of the excavation. Next, additional grout will be pumped into the pit and brought up to a depth sufficient to cover the casing stub by about 6 inches. The remainder of each excavation will be filled with clean material and brought to grade,.and the asphalt will be patched later. 2.3 Over Drilling The V&W hollow-stem drilling rig will be used to over drill all wells so designated in the above well inventory. The auger diameter will be at least as large as the diameter of each original well bore (see table). Each boring will be advanced to the original total depth of each well. The open borings will then be2 closed by filling with Class A/B neat cement conveyed by tremie pipe. Soil cuttings will be temporarily stockpiled in accordance with APCD regulations. During drilling, the soil cuttings will be monitored with a PID organic vapor meter to assure that excessive gasoline vapors do not threated the drilling personnel. 2937 Veneman Ave., Suite B240 Geo-Phase Environmental Inc. Phone: (209) 569-0293 Modesto,Ca 95356 Fax: (209) 569-0295