S.D. Admin. R. 74:29:11:12

Current through Register Vol. 51, page 67, December 16, 2024

Section 74:29:11:12 - Well construction requirements

The method for well construction shall be stated in the permit application. Construction requirements listed in this section apply to all wells installed for activities related to in situ leach mines. The department may grant a deviation from the requirements through a technical revision, if the operator supplies documentation of reliability, mechanical integrity, design, and construction to protect ground waters of the state. Injection and production wells shall be generally constructed as follows:

(1) Annular seals shall be installed to protect the casing against corrosion, ensure structural integrity of the casing, stabilize the upper formations, protect against contamination or pollution of the well from the surface, and prevent migration of ground water from one aquifer or water-bearing strata to another in accordance with the following requirements:

(a) The drill hole shall be of sufficient diameter for adequate sealing and, at any given depth, at least three inches greater in nominal diameter than the outside diameter of the outer casing at that depth. The department may approve an alternative casing design if it provides an equivalent degree of ground water protection;

(b) Before placing the annular seal, the wellbore shall be under static conditions and all loose drill cuttings, rock chips, or other obstructions shall be removed from the annular space by circulating the borehole with water or drilling mud slurry;

(c) The annular sealing material shall be pressure-grouted as required in § 74:02:04:28;

(d) Sealing material shall consist of neat cement grout or bentonite grout mixtures meeting the following requirements:

(i) Cement grout shall be composed of high sulfate resistant Portland cement and shall conform to the requirements of § 74:02:04:53;

(ii) Bentonite grout shall conform to the requirements of § 74:02:04:53.01. The bentonite grout shall be a sodium bentonite material that has been commercially manufactured and specially formulated for use as a well casing seal;

(iii) The sealing material shall be thoroughly mixed before placement so there are no balls, clods, or other features that could reduce the effectiveness of the seal;

(iv) Special quick-setting cement, cement accelerators, retarders, fluid-loss additives, dispersants, extenders, loss-of-circulation materials, and other additives, including hydrated lime to make the mix more fluid or bentonite to make the mix more fluid and reduce shrinkage, may be used, if approved by the department; and

(v) Used drilling mud or drill cuttings from the borehole may not be used as sealing material;

(2) Well casing shall conform to the requirements of §§ 74:02:04:42 to 74:02:04:45, inclusive, and 74:02:04:48. The casing shall be of sufficient strength and diameter to prevent casing collapse during installation, convey liquid at a specified injection/recovery rate and pressure, and allow for sampling. Casing shall be placed with sufficient care to avoid damage to casing sections and joints. All joints in the casing above the perforations or screens shall be watertight. Casing shall be equipped with centralizers placed at a maximum spacing of one per forty feet to ensure even thickness of annular seal and gravel pack; and

(3) Well development shall be done by methods that will not cause damage to the well or cause adverse subsurface conditions that may destroy barriers to the vertical movement of water between water bearing strata.

S.D. Admin. R. 74:29:11:12

33 SDR 160, effective 4/17/2007; 34 SDR 323, effective 7/2/2008.

General Authority: SDCL 45-6B-81.

Law Implemented: SDCL 45-6B-41.