NR 812.14(8)(a)(a) The upper enlarged drillhole shall be a minimum of 4 inches larger than the nominal diameter of the permanent casing and shall extend to the depth of any fractures, voids or caverns encountered greater than 20 feet below the ground surface. NR 812.14(8)(b)(b) The upper enlarged drillhole shall be free of drilling mud or cuttings. NR 812.14(8)(c)(c) Any bentonite chips placed below the water table shall be screened and poured in a manner that prevents bridging. NR 812.14(8)(d)(d) Any bentonite chips placed above the water table shall be hydrated using water meeting the requirements specified in s. NR 812.11 (14). NR 812.14(8)(e)(e) The volume of bentonite chips used shall be limited to the minimum needed to resume grouting according to the requirements specified in s. NR 812.20. NR 812.14(8)(f)(f) The number of bags or volume of chips used, the depth they were placed, and the reason they were needed shall be noted on the well construction report. NR 812.14(9)(9) Dual aquifer prohibition. Wells may not be constructed open to both an unconsolidated formation and a bedrock formation. NR 812.14(10)(10) Wells constructed into the maquoketa shale. Wells constructed or reconstructed to withdraw water from any of the aquifers beneath the Maquoketa Shale and the Niagara formations in the eastern part of the state shall be cased and grouted into the Maquoketa Shale formation except in areas designated by the department as special well casing pipe depth areas. If a liner is used to case off the Niagara formation, the Maquoketa Shale formation or both, it shall be installed and grouted in place in accordance with s. NR 812.21. NR 812.14 HistoryHistory: CR 18-095: r. and recr., Register June 2020 No. 774, eff. 7-1-20; correction in (3) (b) 1., 2. made under s. 35.17, Stats., Register June 2020 No. 774; CR 21-070: am. (3) (a), cr. (3) (e) to (g), am. (4) (intro.), (b) (intro.), (c), cr. (4) (d), (5) (c) 3. Register July 2022 No. 799, eff. 8-1-22. NR 812.15(1)(1) Control of flow. When a well driller or well constructor constructs a flowing well, the flow shall be confined to the interior of the well casing. When the flow of water is not contained to the interior of the well casing using planned construction methods, the well driller or well constructor shall notify the department of the location of the flowing well immediately, and take one of the following actions: NR 812.15(1)(a)(a) Reconstruct the well to contain the flow to the interior of the casing. NR 812.15(2)(2) General requirements. A flowing well constructed with an upper enlarged drillhole shall be grouted in accordance with par. (c). When a new well is constructed to replace a well with uncontrolled flow, the well shall be constructed to meet all of the following requirements: NR 812.15(2)(a)(a) Upper enlarged drillhole requirement. An upper enlarged drillhole shall be constructed in accordance with the requirements specified in subs. (3) or (4). NR 812.15(2)(b)(b) Driving or advancing casing. Steel well casing shall be driven or advanced only through the bottom of an upper enlarged drillhole constructed in accordance with the requirements specified in subs. (3) or (4). The upper enlarged drillhole shall be kept filled with drilling mud with a mud weight of at least 9 pounds per gallon or with dry granular bentonite, which shall be maintained around the outside of the casing. Approved drilling additives may be added to the drilling mud to increase the mud weight. NR 812.15(2)(c)(c) Grouting requirement. The annular space of a flowing well shall be grouted with neat cement using the methods specified in s. NR 812.20. NR 812.15(3)(3) Construction requirements in unconsolidated formations. In addition to the general requirements of this section and the requirements specified in ss. NR 812.10 to NR 812.13, a well driller or well constructor shall construct or reconstruct a flowing well in unconsolidated formations according to all of the following requirements: NR 812.15(3)(a)(a) Upper enlarged drillhole. An upper enlarged drillhole shall be constructed to at least 25 feet or halfway through any known confining bed, whichever is deeper, except when the well is double cased in accordance with par. (e). NR 812.15(3)(b)(b) Minimum diameter. The upper enlarged drillhole shall be a minimum of 4 inches larger than the nominal diameter of any casing to be grouted, except as allowed under par. (e). NR 812.15(3)(c)(c) Method of keeping the hole open. The upper enlarged drillhole shall be kept open during construction using any of the following methods: NR 812.15(3)(c)2.2. Circulating drilling mud with a weight of at least 9 pounds per gallon. Additives approved under s. NR 812.091 may be added to the drilling mud to increase the mud weight. NR 812.15(3)(e)(e) Double cased wells. When a well is double cased, it shall be constructed in accordance with all of the following requirements: NR 812.15(3)(e)1.1. The nominal casing diameter of the outer casing may be reduced to a minimum of 2 inches in diameter greater than the nominal diameter of the inner casing when welded steel or flush-threaded thermoplastic casing is used for an inner casing. NR 812.15(3)(e)2.2. An upper enlarged drillhole shall be constructed into the confining bed in accordance with par. (c). NR 812.15(3)(e)3.3. The outer casing shall be placed in the upper enlarged drillhole and grouted in place according to the requirements specified in sub. (2). The grout shall be allowed to set for a minimum of 24 hours before drilling continues. NR 812.15(3)(e)4.4. A second upper enlarged drillhole shall be constructed to at least the minimum casing depth for the formation encountered and in accordance with par. (c).