Section NR 812.20 - Grouting and sealing A well driller or well constructor shall complete the grouting or sealing of annular spaces and drillholes using all of the following methods and materials as are applicable:
(1) GROUTING AND SEALING MATERIAL. Materials used for grouting and sealing shall meet the requirements specified in s. NR 812.11.(2) GENERAL REQUIREMENTS. (a)Tremie pipes. All of the following general requirements apply to the use of tremie pipes during grouting:1. The tremie pipe shall be placed to the bottom of the upper enlarged drillhole.2. When a tremie pipe is placed on the outside of a casing string, it may not be permanently attached to the casing during setting.3. The tremie pipe shall move freely in the annulus prior to the start of grouting.4. If the tremie pipe is pulled back during grouting, the bottom of the tremie pipe shall remain submerged in grout.5. The tremie pipe shall be removed after grouting. If the entire length of tremie pipe cannot be removed after grouting, the driller shall note the reason that the tremie pipe could not be fully removed on the well construction report for the well.(b)Grouting and sealing. All of the following general requirements apply to the grouting and sealing of wells:1. Grout shall be placed from the bottom of the annular space to the ground surface.2. The density of the grout flowing from the annular space at the ground surface shall be the same as the density of the grout being placed.3. Grout shall be placed in one operation. When grout fails to come to the ground surface in fractured bedrock formations after pumping more than the calculated amount of grout to fill the annulus, the grouting operation may be interrupted to allow the grout to set, or bentonite chips may be used as allowed under s. NR 812.14(8), and grouting shall continue as soon as possible. If circumstances prevent completing the grouting work in one operation, the well driller or well constructor shall report the reason on the well construction report.4. Any settling of the grout more than 6 feet below the ground surface shall be made up by adding grout until it comes back up to the ground surface.5. Cement grouts shall be allowed to set for a minimum of 12 hours before drilling operations continue.(c)Temporary casing removal. When a temporary outer casing is used to construct the upper enlarged drillhole, a well driller or well constructor shall make an attempt to remove the temporary outer casing during or after the grouting process. If possible, the temporary outer casing shall be removed. The grout level shall remain above the bottom of the casing during removal of the casing.(3) PRESSURE GROUT PLACEMENT METHODS. A well driller or well constructor shall complete the pressure grouting of wells using any of the following methods: (a)Tremie pipe-pumped. The grout material shall be placed by a pump through a tremie pipe into the annular space between the well casing pipe and the upper enlarged drillhole wall or inside surface of the temporary outer casing.(b)Grout shoe-continuous injection. The grout shoe-continuous injection method of grouting shall be completed in accordance with all of the following: 1. The bottom of the well casing pipe shall be fitted with a grout shoe equipped with a check valve.2. A tremie pipe or drill stem shall be connected to the grout shoe and shall extend up through the well casing pipe to a grout pump at the ground surface.3. The well casing pipe shall be suspended a short distance above the bottom of the upper enlarged drillhole.4. Grout material shall be pumped through the tremie pipe and the grout shoe until the entire annular space is filled with grout.5. The tremie pipe or drill stem shall be removed and the well casing pipe shall be set to the bottom of the upper enlarged drillhole.(d)Braden-head method. All of the following requirements apply to the use of the Braden-head method of grouting:1. The well casing pipe shall be suspended a short distance above the bottom of the upper enlarged drillhole.2. The well casing pipe and annulus shall be filled with water, drilling mud, or bentonite slurry. A tremie pipe shall be set inside the well casing pipe to the bottom and shall extend watertight through a sanitary well seal installed securely in the top of the well casing pipe. A packer may be installed inside the well casing pipe, at depth, as an alternative to using a well seal at the top.3. The grout shall be pumped down the tremie pipe and up the annular space.4. Immediately following grout flow at the surface, the well casing pipe shall be set to the bottom of the upper enlarged drillhole of an unconsolidated formation well or driven to a firm seat in bedrock.(e)Grout displacement method. The grout displacement method may only be used for wells when the upper enlarged drillhole is less than or equal to 200 feet deep or when drilling mud or bentonite slurry has been circulated in the upper enlarged drillhole from the bottom up to the ground surface prior to the grouting. All of the following requirements apply to the use of the grout displacement method:1. The well driller or well constructor shall place a measured volume of grout that is equal to the volume of the annular space plus at least 15% into the upper enlarged drillhole through a tremie pipe.2. The well casing pipe shall be fitted with centering guides and a drillable plug at the bottom and shall be lowered through the grout to the bottom of the upper enlarged drillhole allowing the grout to be forced up into the annular space.3. If necessary, pressure shall be applied and maintained on the top of the well casing pipe to hold it in place for at least 12 hours or until the grout sets, whichever is longer. Water may be added to the well casing pipe to provide extra weight.4. If the grout does not flow at the ground surface, the remainder of the annular space shall be filled with grout placed through a tremie pipe that shall be at the drill site.(4) NON-PRESSURE GROUTING. The tremie pipe-gravity method of non-pressure grouting may be used when the upper enlarged drillhole is less than 100 feet deep and is at least 4 inches larger in diameter than the nominal diameter of the well casing pipe. Grout material may flow by gravity through a funnel or hopper connected to a tremie pipe that extends to the bottom of the upper enlarged drillhole.Wis. Admin. Code Department of Natural Resources NR 812.20
Cr. Register, January, 1991, No. 421, eff. 2-1-91; am. (3) (c), (4) (a) and (b), Register, September, 1994, No. 465, eff. 10-1-94; CR 13-096: cr. (1) (a) 7., am. (1) (c), (d), cr. (1) (e) to (h), am. (2) (c), (j), (3) (a), (b) Register September 2014 No. 705, eff. 10-1-14.Amended by, CR 18-095: r. and recr. Register June 2020 No. 774, eff. 7/1/2020