17.24.1005    DRILL HOLES

(1) Prospecting operations must be conducted to completely avoid:

(a) degradation or diminution of any existing or potential water supply; and

(b) adverse impacts to existing or potential mining operations. All prospecting holes must be abandoned in accordance with the following provisions unless the hole has been transferred as a water well in compliance with ARM 17.24.647 or unless a delay is approved by the department.

(2) The prospector shall use appropriate techniques to:

(a) prevent the escape of water, oil, or gas from all drill holes;

(b) prevent contamination of all surface and ground waters, and prevent interaquifer mixing;

(c) prevent aquifer contamination by surface drainage; and

(d) reclaim all surface impacts and prevent settling that may result from prospecting-related activities.

(3) Unless alternative procedures are approved or required by the department, the prospector shall use the following reclamation techniques:

(a) cuttings must be spread over the earth's surface to a depth less than 1/2 inch or be removed to an approved disposal pit. Cuttings must not be placed in the hole. Proper soil salvage and reclamation techniques consistent with ARM 17.24.501 and 17.24.701 through 17.24.703 must be used at the disposal pit;

(b) whenever a cased drill hole is not transferred to the affected landowner as a water well, the casing must be cut off at the surface on rangeland and two feet below the surface on cropland or pastureland;

(c) promptly after prospecting on a site is completed, and unless otherwise approved by the department, all drill holes must be abandoned in accordance with the following:

(i) Whenever circulation is lost to the formation or artesian conditions are encountered, a homogeneous cement grout must be slurried into the hole from the bottom to within two feet of the surface and topsoil placed in the remaining two feet.

(ii) Whenever circulation is not lost, a swelling bentonitic clay grout with no less than 50% bentonite solids per unit volume must be placed in each abandoned drill hole, from the bottom of the hole to within two feet of the land surface. Precautions must be taken to ensure that no bridging occurs between the bottom and top of the hole. The entire hole must be filled with the grout to form a continuous grout column from bottom of the hole to two feet below the natural land surface.

(iii) A magnetic marker must be placed on the top of the grout. The remaining two feet of the hole must be backfilled with cuttings or suitable soil material;

(d) A detailed description of all methods and materials to be used for casing and grouting all water wells, monitor wells, or holes that are not abandoned in accordance with (c) immediately after drilling must be provided to the department. All cased holes, water wells, and monitor wells must be completed in a manner approved by the department. All wells and other drill holes must be constructed and maintained in compliance with the performance standards contained in ARM 17.24.632, 17.24.647, 17.24.1005, and 17.24.1011 through 17.24.1013, and ARM Title 36, chapter 21, subchapters 6 and 8.

(4) If excavations, artificially flat areas, or embankments are created for or during prospecting, they must be promptly returned to approximate original contour after they are no longer needed for prospecting.

History: 82-4-205, MCA; IMP, 82-4-226, MCA; NEW, 1980 MAR p. 725, Eff. 4/1/80; AMD, 1989 MAR p. 30, Eff. 1/13/89; AMD, 1995 MAR p. 31, Eff. 1/13/95; TRANS, from DSL, 1996 MAR p. 3042; AMD, 1999 MAR p. 811, Eff. 4/23/99; AMD, 2012 MAR p. 737, Eff. 4/13/12; AMD, 2024 MAR p. 258, Eff. 2/10/24.