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Mr. Gil Moore July 13, 2012 <br /> 6437 Banner Street, Lodi Page 2 of 3 <br /> Well Destruction r Work Plan <br /> review additional technical justifications later provided by AGE on 14 Nlay 2012 to support the <br /> proposal for pressure grouting most of the fourteen wells. <br /> To summarize. the AGE technical justifications supplied to EHD were based on traffic safety <br /> concerns. convenience of local businesses and fire station. and contaminant concentration <br /> decline trends or inferences of lack of contamination derived from nearby wells. EHD <br /> investigated and evaluated all these issues and found the following: <br /> Any active traffic creates some risk of injury to workers in the area; however, EHD visited <br /> the site and found that unusually heavy or fast traffic conditions were not observed and <br /> visibility appeared to be good along the roadway. No safety concerns were found that <br /> could not be mitigated by proper traffic control methods commonly used by well <br /> contractors and consultants who routinely install and destroy monitoring wells at this <br /> type of site. <br /> An interview conducted with the officer of the fire station found that the station could <br /> easily take steps to accommodate the presence of a drill rig for destroying the wells in its <br /> area, all the while still being able to provide the level of response required during <br /> incidents of fire. <br /> The local businesses should not be inconvenienced any more in the process to destroy <br /> the wells than when the wells were constructed. <br /> The declining concentration trends were developed from data collected during active <br /> remediation and are not likely to represent the contaminant degradation rate under <br /> natural conditions. <br /> © The contaminant concentrations in the wells compared to one another when sampled at <br /> the same time displayed a poor correlation between wells, so one well could not be <br /> reliably used to predict the contaminant concentrations in the nearby well. <br /> As such. the EHD has determined that the fourteen wells must still be destroyed by removing <br /> the well contents. <br /> The AGE well destruction proposal for the fourteen wells submitted to EHD on 11 June 2012 <br /> has been reviewed. The proposal, which the consultant referred to as the `popsicle' method, <br /> involves pulling the well casings from the borehole and grouting the remaining open bore hole <br /> through the casing during its removal. In instances where the casing cannot be successfully <br /> removed, it is proposed that the well then be pressure grouted and over-drilled to the saturated <br /> zone and finished by grouting the remaining open borehole to surface grade. This procedure <br /> would not meet .destruction requirements of Section 13.17.6 and several elements of this <br /> method are of concern: <br /> r If the well casing can be successfully removed, but only a portion or none of the cement <br /> grout seal pulls out with it, the residual annular grout seal will be adjacent to the grout <br /> introduced to seal the open hole. Well Standard Section 13.17.9., requires that "Sealing <br /> materials shall be placed in one continuous operation unless conditions in the well or <br /> boring dictate that sealing operations be conducted in a staged manner and prior <br /> approval is obtained from the Director." When repairing broken cement with neve cement, <br /> the new often does not adhere well to the older cement, thus a ver tical space may be left <br />