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13.17. REQ FOR DESTROYING MONITORING WELLS AND EXPLORATION HOLES <br /> 13.17.1. A monitoring well shall be investigated to determine its condition and details or its <br /> construction prior to its destruction. <br /> 13.17.2. The well shall be sounded immediately before it is destroyed to determine whether <br /> there are obstructions that will interfere with filling and sealing. <br /> 13.17.3. Any obstructions found in the well or boring shall be removed before filling and <br /> sealing operations begin. <br /> 13.17.4. If the well was constructed and maintained in accordance with these Standards, the <br /> sealing material shall be placed under pressure to ensure that the monitoring well is <br /> properly filled and sealed. <br /> 13.17.5. Casing material may require perforation, or puncturing, to allow for proper <br /> placement of sealing materials. <br /> 13.17.6. If the well construction is unknown and/or is located in an area of known or <br /> suspected pollution or contamination, the well shall be destroyed by removing all <br /> _material within.the Driginal borehole.(including-the well casing, screen, filter pack, <br /> and annular seal); and the created hole filled completely with appropriate sealing <br /> material. <br /> 13.17.7. Exploratory borings, installed for sampling purposes, shall be completely grouted <br /> with appropriate sealing material. The top 3 feet of the boring may be backfilled <br /> with clean, uncontaminated fill material. <br /> 13.17.8. The well or exploratory boring shall be filled by use of a tremie pipe or equivalent, <br /> proceeding upward from the bottom of the well or boring. Any deviation from this <br /> method must be approved by the Director. <br /> 13.17.9. Sealing materials shall be placed in one continuous operation unless conditions in the <br /> well or boring dictate that sealing operations be conducted in a staged manner and <br /> prior approval is obtained from the Director. <br /> 13.17.10. Pressure requirejv for the placement of sealing material shall be maintained long <br /> enough for sealing materials to properly set. <br /> 13.17.11. Verification shall be made to determine that an adequate seal has been installed by <br /> a EHD representative. <br /> 13.17.12. If the well casing was left in place during sealing operations, a hole at least one foot <br /> larger in diameter than the originally drilled hole shall be excavated around the <br /> outside of the well casing to a depth of 3 feet below the ground surface, and the well <br /> casing shall then be cut off 6 inches above the bottom of this excavation and <br /> removed. <br /> 13.17.13. The grout used to fill the well shall be allowed to spill over into the excavation, <br /> during the sealing operation, and fill it for a thickness of one foot and form a "cap" <br /> which has a diameter of at least one foot greater than the diameter of the originally <br /> drilled hole. <br /> 13.17.14. After the sealing operation and the sealing material has set, the excavation shall be <br /> filled with clean soil. <br /> 13.17.15. Any deviation from this section must obtain prior approval from the Director. <br />