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used if water or any visible obstruction is present in the annular space <br /> within the applicable minimum grout depth specified in this Rule at <br /> the time of grouting, with the exception that bentonite chips or pellets <br /> may be used if water is present and if designed for that purpose. <br /> d. The annular space of the top twenty(20) feet for wells grouted with <br /> bentonite chips or pellets must be no less than ten (10) inches in <br /> diameter for a six (6) inch casing. <br /> 5. If a Rule of this Section requires grouting of the casing to a depth greater than <br /> 20 feet below land surface, the pumping or pressure method shall be used to <br /> grout that portion of the borehole deeper than 20 feet below land surface, with <br /> the exception of bentonite chips and pellets. <br /> 6. If an outer casing is installed, it shall be grouted by either the pumping or <br /> pressure method. <br /> 7. Bentonite chips or pellets shall be used in compliance with all manufacturer's <br /> instructions including pre-screening the material to eliminate fine-grained <br /> particles, installation rates, hydration methods, tamping, and other measures <br /> to prevent bridging. <br /> 8. Bentonite grout shall not be used to seal zones of water with a chloride <br /> concentration of 1,500 milligrams per liter or greater. <br /> 9. The well shall be grouted within seven days after the casing is set. When grout <br /> is emplaced by gravity, the entire drilling process must be completed prior to <br /> grout emplacement. When emplaced by the pump or pressure methods, the <br /> grouting process may be initiated at any time after the casing is set, including <br /> during the drilling process. <br /> 10. It is the responsibility of the well contractor to verify that the grout does not <br /> settle. Any settling greater than five (5) feet below the natural land surface <br /> shall require re-inspection. <br /> 11. No additives which will accelerate the process of hydration shall be used. <br /> 12. Where grouting is required by the provisions of this Section, the grout shall <br /> extend outward in all directions from the casing wall to a minimum thickness <br /> equal to either one-third of the diameter of the outside dimension of the casing <br /> or two inches, whichever is greater; but in no case shall a well be required to <br /> have an annular grout seal thickness greater than four inches. <br /> 13. For wells constructed in locations where flowing artesian conditions are <br /> encountered or expected to occur, the well shall be adequately grouted to <br /> protect the artesian aquifer,prevent erosion of overlying material and confine <br /> the flow within the casing. <br /> History Note: Substitute for NCAC 02C.0107 <br /> Eff. July 1, 2008; amended eff. October 23, 2009;March 25, 2020 <br /> 24 <br />