SITE INFORMATION AND CORRESPONDENCE

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be limited to neat cement, or cement with bentonite(not to exceed 5%)as indicated on the original permit, and an attempt should be made to remove the silt thereby providing a more protective destruction of this potential vertical conduit. The well decommissioning was scheduled for February 6, 1998 although the contractors were informed that heavy rains were forecast for that day. On February 6, 1998 PHS/EHD staff including one senior staff and two site mitigation trainees arrived on site to witness the well destruction. Upon arrival the C-57 license holders representative inquired regarding the use of grout with aggregates suggesting that it was the only alternative available as due to heavy rains,a limited number of concrete batch plants were open. PHS/EHD informed him of the limitations regarding acceptable grout mixtures as presented by earlier telephone communications and as found on the original permit. In short his request was denied. He then indicated that he would have to find a new source for grout materials as the vendor he had selected was unwilling to deliver neat cement. He later returned to inform the PHS/EHD staff that there would be a considerable delay before the materials could be delivered. At that time PHS/EHD staff recommended that the job be postponed, however, both EMCON and Water Development representatives requested that they continue. PHS/EHD staff departed from the site and returned later that afternoon. At that time PHS/EHD staff inquired regarding the proposed method of destruction and were informed that the well would not be perforated as approved, nor would the silt be removed and suggested that they would tremie pump grout beginning at 55 feet bgs to 3 feet bgs, then physically remove the well casing with a cable and winch system with no means to apply pressure at 35 to 40 psi at the well head since the well casing would be removed. PHS/EHD informed the contractors that this was a significant deviation from the original proposal and that this approach was not in compliance with San Joaquin County Well Standards. In addition PHS/EHD staff informed both contractors that it was unlikely that PHS/EHD would sign off on the well destruction if they proceeded. The contractors then informed PHS/EHD staff that CVRWQCB had provided written approval which did not require perforation of the well casing. Again,PHS/EHD informed the contractors that this was a significant deviation from the original proposal, PHS/EHD had no knowledge of any written approval which did not require perforation or pressure grouting and it was unlikely that PHS/EHD would sign off on the well destruction if they proceeded. The contractors elected to continue, ignoring PHS/EHD warnings. PHS/EHD staff members then observed the following events. The contractors tremied in approximately four yards of neat cement,the depth to grout in the bore hole/casing was not visible but was estimated at 10 to 15 feet below surface grade. Having depleted their grout material on hand without reaching surface grade, the contractors informed PHS/EHD that they would need to return to a south county (Ripon) batch plant for additional neat cement with no known time frame for completion of the grouting process. At that time PHS/EHD staff informed the contractors that all well grouts must be completed as a continuous pour per Section 4.7.4. of the PHS/EHD Well Standards. The intent of this requirement includes but is not limited to eliminating the potential for joints, mixing of grouting materials with bore hole matrices, and bridging which may compromise the quality of the seal. This issue is important recognizing the findings of the down hole video log which revealed significant voids between the existing casing and bore hole wall (annular space). Water Development then proceeded to remove the tremie pipe after being directed verbally to leave the tremie pipe in place. Water Development then began to remove the well casing with a cable and winch system. PHS/EHD again informed the contractors that this was not acceptable recognizing that without the tremie pipe in place they would have no control of the bore hole with regard to collapse and potential bridging. In addition the contractors were informed by PHS/EHD that it was unlikely that the entire corroded well casing would be removed employing this method. Again the contractors ignored PHS/EHD comments and proceeded. Water Development then proceeded to remove the well casing, as the well casing was removed their representative used a hand held electric grinder to physically cut the steel casing generating a visible spark trail in excess of 15 feet long in an area(bulk fuel storage) which is posted, restricting the use of ignition sources although he was verbally directed to stop. Water Development removed approximately 40 feet of casing before the weak and corroded casing broke below grade. The quantity of casing remaining, its relative position, and condition in this bore hole is now unknown. 2