SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

Y)EPARTMENT ENVIRON! ENTAL HEALTH Y.v`" SAN JOAQUIN COUNTY 2 Program Coordinators 4 <, Donna K. Heron, R.E.H.S. 304 East Weber Avenue,Third Floor Carl Borgman,R.E.H.S. Director Mike Huggins, R.E.H.S., R.D.I. Laurie A. Cotulla, R.E.H.S. Stockton, California 95202-2708 Margaret Lagorio, R.E.H.S. • eq `.a:P Assistant Director Telephone: (209)468-3424 Robert McClellon, R.E.H.S. �iFOR Fax: (209)464-0138 Jeff Carruesco, R.E.H.S. Website:www.sjgov.org/ehd/ Kasey Foley,R.E.H.S. DON PRATT NOV Q 2 2006 ENVIRONMENTAL BUSINESS MANAGER ATLANTIC RICHFIELD COMPANY P O BOX 1257 SAN RAMON CA 94583 RE: ARCO Station No. 5450 SITE CODE: 1296 1617 Fremont Street Stockton, California San Joaquin County Environmental Health Department (EHD) has reviewed Revised Work Plan for Well Destruction dated October 23, 2006, submitted by SECOR International Incorporated (SECOR) on your behalf In this work plan, SECOR proposes to destroy the three onsite monitoring wells in accordance with San Joaquin County Well Standards Section 13.17 (Well Standards). Specifically, SECOR proposes to destroy monitoring well MW-3 by pressure grouting "from total depth to approximately ground surface using neat cement. After pressure grouting, the upper five feet of the well casing will be over-drilled." This procedure for well destruction does not follow San Joaquin County Well Standards Section 13.17 requirements for destroying monitoring wells. Please note that the Well Standards state that "If the well casing was left in place during sealing operations, a hole at least one foot larger in diameter than the originally drilled hole shall be excavated around the outside of the well casing to a depth of three feet below the ground surface, and the well casing shall then be cut off six inches above the bottom of this excavation and removed. The grout used to fill the well shall be allowed to spill over into the excavation during the sealing operation, and fill it for a thickness of one foot and form a `cap' which has a diameter of at least one foot greater than the diameter of the originally drilled hole." EHD approves the destruction of MW-3 by pressure grouting using the procedure just described, or MW-3 may be destroyed by removing all of the well contents by drilling out the original borehole and filling it with grout using a tremie pipe system. EHD also approves the destruction of MW-2 and MW-4 by removing all of the well contents by drilling out the original borehole to total depth, and backfilling the borehole to three feet below surface grade with neat cement using a tremie pipe system. Groundwater expelled from the wells during the grouting procedure will be contained, characterized, and disposed of properly.