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' Revised Workplan for Abandonment of MW3, Installation of MWS, and Additional Soil Borings at ' Chinebiolo Stemilt California & Sierra Hills Packing, Inc. ' Background The scope of this workplan generally consists of 1) drilling three soil borings (B5, B6, and B7) in order to document subsurface lithology, 2) completing one of those borings (B7) as a monitoring well (MW5), and 3) abandoning an existing monitoring well (MW3). Also, a water sample from a perched groundwater zone is to be collected for ' laboratory analysis during drilling B7 /MWS. Four groundwater monitoring wells were installed at the site beginning November 2004 ' in accordance with the Groundwater Investigation Workplan, October 1, 2004 (amended October 15, 2004). Subsequent sampling at MW-3 revealed an unusually high pH and electrical conductivity in the groundwater at the well. This condition is characteristic of ' "grout contamination"which is usually caused by an ineffective bentonite seal separating the sandpack at the base of the well from the annular grout backfill higher up in the well boring. A request to abandon the well by grouting the inside of the well pipe was ' submitted to the Regional Water Quality Control Board(Board) on February 16, 2005, but was not approved. One purpose of this workplan is to detail procedures used to abandon MW-3 by over-drilling the well followed by grouting the over-drilled bore hole from bottom to top. A plan to install MW5 as a replacement well for MW-3 was submitted to.the Board on ' February 16, 2005, and again on April 18, 2005. Being a replacement well, it was to be installed in accordance with the existing Groundwater Investigation Workplan, October 1, 2004(amended October 15, 2004). One purpose of this workplan is to detail ' procedures used to install MW5 to an anticipated depth of 125 feet, and additionally to collect a grab groundwater sample from a perched groundwater zone at approximately 65 feet below ground level during drilling. ' In a letter dated March 22, 2005, the Board Staff indicated that they believe a saturated interval exists at the site at approximately 65 to 80 feet below ground level (BGL). One purpose of this workplan is to detail procedures used to install two soil borings (B5 and B6) to investigate the existence and/or extent of this saturated zone. Borings B5 and B6 will be installed prior to drilling B7/MW-5. Should saturated conditions be encountered ' at approximately 65 feet BGL in both B5 and B6, then drilling for B7/MW5 will be postponed and the proposed construction of MW5 outlined in this document will be re- evaluated in consideration of the new information. June 21,2005 Page 1