S.C. Code Regs. § 61-71.J
Current through Register Vol. 48, 12, December 27, 2024
Section 61-71.J - GEOTHERMAL SYSTEM WELLS1. Drilling. a. The drilling process or use of drilling fluid additives shall not contaminate any aquifer.b. Water used in the drilling process shall be obtained from a source that will not result in chemical or biological contamination of any aquifer. Water taken directly from ponds, lakes, streams or other surface water sources shall not be used.c. Geothermal system wells shall not connect aquifers or zones that have documented differences: (1) In water quality that would result in contamination of any aquifer or zone such that any State Primary Drinking Water standard is exceeded;(2) In static water levels that would result in depletion of water from any aquifer or zone, or significant loss of head in any aquifer or zone. 2. Grouting. a. If the geothermal system well is to be cased, the diameter of the drilled hole shall be large enough to allow for a minimum of 1.5 inches of annular space on all sides of the casing for forced injection of grout through a tremie pipe. Grout shall fill the entire annular space from a minimum depth of twenty feet from the land surface at the time of well completion, unless otherwise approved by the Department.b. If the geothermal system well will not be cased, the borehole may be filled with either bentonite-cement, neat cement, 20% high solids sodium bentonite grout, sand, or gravel to no closer than twenty feet below the ground surface. The remaining twenty feet to the ground surface shall be filled with neat cement, bentonite-cement, or 20% high solids sodium bentonite grout.c. Grout is to be composed of neat cement, a bentonite cement mixture, or high solids sodium bentonite grout.(1) Neat cement grout shall be composed of Class A, Type I Portland Cement mixed with not more than seven (7) gallons of clean water per bag (one cubic foot or 94 pounds) of cement with a density of 15 to 16 pounds per gallon, or to manufacturer's specifications.(2) Bentonite-cement grout shall be composed of powdered bentonite (less than 5% by weight) mixed at not more than 8 gallons of water to the bag, with a density of 14 to 15 pounds per gallon, or to manufacturer's specifications.(3) High solids sodium bentonite grout shall have a minimum of 20% solids and be mixed per manufacturer's specifications with water and/or other required additives.d. All grouting shall be accomplished using forced injection to emplace the grout. When emplacing the grouting material, the tremie pipe shall be lowered to the bottom of the zone to be grouted. The tremie pipe shall be kept full continuously from start to finish of the grouting procedure, with the discharge end of the tremie pipe being continuously submerged in the grout until the zone to be grouted is completely filled.e. Geothermal system wells shall be grouted in-place within five (5) days after borehole completion.f. When high solids sodium bentonite grouts are used, a vapor barrier at the land surface at least the width of the annular space made of suitable materials, as approved by the Department, such as native soils, gravel, sand, or thermoplastic material, is required for public safety and structural stability of the well.3. Well Identification. These wells shall be properly labeled with an identification plate immediately upon well completion. The identification plate shall be constructed of a durable, weatherproof, rustproof, material. The identification plate shall be permanently secured to the well casing or enclosure floor around the casing where it is readily visible. The identification plate shall be permanently marked to show:
a. Company name and certification number of the driller who installed the well;b. Date well was completed;c. Total depth (feet); and,4. Reporting. The Water Well Record Form 1903, or other approved form, shall be completed and submitted to the Department by the contractor within thirty days after well completion.