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'+ ENVIRON-MENTAL HEALTH 11EPARTMENT <br /> a4.U± SAN JOAQUIN COUNTY <br /> '. ,� a donna K. Heran, R.E.H.S. Unit Supervisors <br /> Director 304 East Weber Avenue,Third Floor Car]Borgman,R.E.H.S. <br /> Al Olsen, R.E.H.S. Stockton,California 95202-2708 Mike Huggins, R.E.H.S., R.D.I. <br /> S ger <br /> ram Pro Manager Telephone: (209)468-3420 Douglas W.Wilson, R.E.H.S. <br /> q •.:.....••� <br /> Laurie A. Cotulla, R.E.H.S. Margaret Lagorio,R.E.H.S. <br /> Program Manager Fax: (209) 464-0138 Robert McClellon, R.E.H.S. <br /> Website:www.sjgov.org/ehd/ Jeff Carruesco, R.E.H.S. <br /> DOUG STIDHAM KULJIT MANGAT AUG '3 -1 2005 <br /> CITY OF ESCALON 622 CLAY WAY <br /> PO BOX 248 RIPON CA 95336 <br /> ESCALON CA 95320 <br /> RE: South County Food & Fuel SITE CODE: 1487 <br /> 1 305 Escalon Avenue <br /> Escalon CA 95320 <br /> San Joaquin County Environmental Health Department (SJC/EHD) has reviewed Work <br /> Plan— Well Abandonment dated August 11, 2005, prepared and submitted on your behalf <br /> by Geological Technics Inc. (GTI) and has the following comments. <br /> The work plan proposes the destruction by pressure grouting of six groundwater <br /> monitoring wells and four soil vapor extraction wells. <br /> San Joaquin County well standards require wells destroyed by pressure grouting to be <br /> surface completed by excavation of a hole at least one-foot larger in diameter than the <br /> original borehole around the well casing, to a depth of three feet below surface grade. <br /> The well casing shall then be cut six inches above the bottom of the excavation. After the <br /> well casing has been properly filled with grout and pressurized, the cement grout will be <br /> allowed to pour over the top of the cut casing to form a mushroom cap at least one-foot <br /> thick in the excavation. Monitoring wells MW-1, MW-2, MW-4, MW-5 and MW-101, and <br /> vapor wells VEW-3 and VEW-4 shall be completed in the above described manor. <br /> Vapor wells VEW-1 and VEW-2 were located near the eastern edge of the site; these <br /> wells were subsequently covered with the sidewalk and/or part of Escalon Avenue. Prior <br /> to completion of the road construction these wells were connected to underground <br /> conveyance piping laid in a 4-foot deep trench that ended in a common vault near VEW-3 <br /> and VEW-4 in the center of the site. VEW-1 has a total depth of 55 feet below surface <br /> grade (bsg); VEW-2 has total depth of 27 feet bsg. GTI has proposed destruction of these <br /> well by pumping grout to total depth of each well through 1-inch diameter poly tubing, <br /> followed by pressurization. SJC/EHD approves this method with the condition that GTI <br /> verifies that the appropriate length of tubing is installed in each well to ensure the grout <br /> reaches the bottom of the well, and that an appropriate minimum quantity of grout is used <br /> in the destruction. The horizontal piping may have to be cut back from the vault area to <br /> ensure proper surface completion of VEW-3 and VEW-4. <br /> Monitoring well MW-3 is located in a narrow curb median In the middle of Escalon Ave. <br /> This well can be destroyed per the procedure proposed in the work plan. <br />