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DUDEK & ASSOCIATES, INC. 605 Third Street Encinitas,CA 92024 (619)942,5147 • Fax No.(619)632-0164 August 3, 1993 4.50-01 Mr. Douglas P. O'Neal Department of Toxic Substances Control California Environmental Protection Agency 10151 Croydon Way Sacramento, CA 95527 Re: Proposed Method of Decommissioning Monitor Well KS-LS, Kearney-IKPF Facility, Stockton, CA. Dear Mr. O'Neal: The purpose of this letter is to outline the method that will be used to destroy monitor well KS- 15 at the Kearney-KPF site in Stockton, CA. We have discussed the decommissioning of well KS-15 with Mr. Richard McJunkin of your department and arrived at the method described below. As you are aware, monitor well KS-15 is located east of the Kearney-KPF facility on property belonging to Croyden Associates. Kearney was granted access to the property to construct the well under an agreement between Kearney and Croyden. The terms of this agreement allow Croyden to rescind access and request that Kearney destroy well KS-15 after four consecutive quarterly groundwater sample analyses indicate less than detectable concentrations of volatile organic compounds. That condition has been met, and Croyden has requested that Kearney destroy the well. Monitor well KS-15 was constructed with a total depth of 92 feet below land surface (bls). Well KS-15 is completed in the first water encountered and as such is a water table well. Well KS-15 was constructed in a 9-7/8 inch borehole and was completed with 4 inch internal diameter schedule 40 PVC casing (Fi;ure 1). The casin- is perforated from 62 to 87 feet bls with factory cut 0.020 inch slots. A filter pack comprised of 2!121 Monterey silica sand extends from total depth to 92 feet bls. Layers of No. 60 foundry sand and hydrated bentonite pellets overlie the filter pack from approximately 56 to 50 feet bls. The annulus from the bentonite layer to land surface is filled with a cement grout. Based on the fact that the well is completed at the water table and on the well's present annular seal, well KS-15 will not constitute a potential conduit between water bearing zones. It is proposed that a neat cement -rout be injected into the casing to fill the casing and the pore spaces in the filter pack. The well will not be pressurized, but the wei-ht of the column of neat cement pn.,e l nn re y.W papa