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GROUND ZERO ANALYSIS, INC. 1714 Main Street Escalon, California 95320 - Telephone: (209)838-9888 Facsimile: (209)838-9883 October 31, 2001 , Ms. Margaret Lagorio San Joaquin County Public Health Services Environmental Health Division 304 E. Weber Ave., 3rd Fl. Stockton, CA 95202 Subject: Workplan for Additional Site Activities 102 South Wilson Way, Stockton, California Dear Ms. Lagorio: Ground Zero Analysis, Inc. (Ground Zero) has prepared this Workplan on behalf of the Knowles Family 1993 Revocable Trust in response to your directive letter dated July 20, 2001. This Workplan describes the proposed methodology for the destruction of existing monitoring well MW13, proposes the installation of additional monitoring wells and discusses remedial alternatives. This letter also addresses issues raised by PHS/EHD in the July 20 correspondence. The location of the site is shown on Figure 1. WORKPLAN Destruction of Monitoring Well MW13 San Joaquin County Public Health Services, Environmental Health Division (PHS/EHD) and the CA Regional Water Quality Control Board (RWQCB) have expressed concern that monitoring well MW13 may act as a conduit for contamination migration and have ordered that the well be destroyed. While we disagree with this assessment, the well will be destroyed. The location of well MW 13 is shown on Figure 2. A C-57 licensed drilling contractor will destroy the well by pressure grouting with neat cement. Prior to destruction, total depth of the well will be measured to ensure no obstructions are present. Neat cement grout will be pumped through tremie equipment in one continuous operation until the well is completely full. Additional cement will then be added under pressure in order to force the grout through the well screen and into the filterpack, ensuring an adequate seal. Pressure will be applied for a minimum of 15 minutes after completely filling the well with cement grout. I roek\c1osure\workp1m\respome.doc