36.22.502    PLUGGING AND ABANDONMENT

Unless otherwise agreed to between the surface owner; the company, firm, corporation, or individual responsible for the drilling of seismic shot holes; and the board's designated inspector, all such holes shall be plugged and abandoned as set forth below; provided, however, that before the surface owner agrees to a plugging method which deviates from this rule, he must be given a copy of this rule:

(1) The seismic company responsible for the plugging and abandonment of seismic shot holes shall notify the board in writing at its Billings office of its intent to plug and abandon, including the date and time such activities are expected to commence, the location by section, township and range of the holes to be plugged, and the name and telephone number of the person in charge of the plugging operations. A copy of this notice shall be sent to the surface owner at the same time.

(2) All seismic shot holes shall be plugged before shooting. Exceptions may be granted after approval by the board's designated inspector. In the event the original plug does not hold, the hole shall be properly plugged as soon as reasonably practicable; however, in no event shall any hole remain unplugged for a period of more than 30 days unless, upon application, the board or its staff grants an extension which may not exceed 90 days. All holes shall be temporarily capped during the period between drilling and final plugging.

(3) When drilling seismic shot holes, and non-artesian water is encountered or when water is used in conjunction with the drilling, plugging shall be accomplished by filling the hole with coarse ground bentonite from the bottom up to 5 feet above the static water level with a minimum of 100 pounds of bentonite. The hole shall be further filled and tamped with cuttings to a depth of three feet below ground level. All shot holes drilled in the glacial till area of Montana as

shown on USGS Miscellaneous Geologic Investigations Map I-327 shall be filled with coarse ground bentonite from the bottom to 3 feet below the surface. A commercial plug shall be set at this depth with a permit number or the name of the contractor either imprinted on the plug or on a plastic or metallic tag securely attached to the plug. The remainder of the hole shall be filled with cuttings and soil, and a sufficient mound shall be left over the hole to allow for settling.

�

(a) With the approval of the board's designated inspector the shot hole may be plugged by filling the hole with bentonite-water slurry by hose injection and displacement upwards from the maximum depth attainable. The slurry mixture shall have a marsh funnel viscosity of 60 seconds or greater per quart (subject to field verification on site) and shall contain a minimum of 28 pounds of commercial plugging bentonite per 42 gallons of water. The hole shall be filled to a depth of 3 feet below ground level and the commercial plug shall be set at this depth. The remainder of the hole shall be filled with cuttings and soil, and a sufficient mound shall be left over the hole to allow for settling.

(b) Seismic holes that penetrate artesian water deposits shall be stabilized with a cement slurry to a level not higher than three feet below the surface of the ground. The cement slurry shall be of sufficient density to contain the waters to their native strata. The remainder of the hole shall be filled with native surface material. When alkaline or saline waters are encountered, the hole shall be plugged immediately as set forth in (3) and (a) except, if the bentonite-water slurry method is used, a heavier slurry mix must be used with the addition of inorganic drying or stabilizing chemicals such as calcium chloride, sodium bicarbonate, or soda ash to assist in the effective plugging and stability of the bentonite column in the hole.

(c) In completely dry holes, plugging shall be accomplished by filling the hole with not less than 50 pounds of coarse ground bentonite followed by the cuttings. The returned cuttings shall be tamped to insure the hole is not bridged. The hole shall be filled to a depth of 3 feet below the surface and the commercial plug set and topped with cuttings and soil as prescribed by paragraph (3) (a) .

(i) With approval of the board's designated inspector, the shot hole may be plugged by filling the hole with the bentonite-water slurry mixture as set forth in paragraph (a) .

(d) Seismic shot holes that crater or slough at the surface after being shot shall be plugged as set forth in subsections (3) , (a) and (b) insofar as those procedures are reasonably possible. However, deviations from those procedures are permissible as circumstances may dictate, provided the procedures are designed to accomplish the primary objective of containing waters penetrated by the hole to their native strata and restoring the surface as near as practicable to its original conditions. The board and surface owner shall be notified of such deviations.

(4) The surface area around each seismic shot hole shall be restored to its original condition in so far as such restoration is practicable. Cuttings shall be spread no deeper than 1 inch thick and all stakes, markers, cables, ropes, wires, primacord, cement or mud sacks, and any other debris or material not native to the area shall be removed from the drill site and deposited in a convenient sanitary landfill or other approved site or disposed of by an approved disposal method. Appropriate seeds shall be planted when required to restore the surface to its original condition.

(5) A seismic shot hole may be left unplugged at the request of the surface owner for conversion to a fresh water well provided the surface owner executes a release on Form No. 19 relieving the party otherwise responsible for the plugging and abandonment of the hole from any liability for damages that may thereafter result from the hole remaining unplugged. This release will cite the date, location, surface elevation, depth to aquifer, and any action taken. This information shall be furnished by the geophysical operator. The surface owner must also notify and file within 30 days appropriate forms with the water rights bureau of the department of natural resources and conservation. The surface owner must also apply for a permit from the board of water well contractors, and explain in detail the procedures to be used in constructing the well. This is to insure that the shot hole is properly constructed, cased and developed into a water well, according to the minimum construction standards for water wells, as adopted by the board of water well contractors.

History: Sec. 82-1-104, MCA; IMP, Sec. 82-1-104, MCA; NEW, 1977 MAR p. 1196, Eff. 12/24/77; AMD, 1982 MAR p. 1964, Eff. 10/29/82; AMD, 1983 MAR p. 1193, Eff. 8/26/83; AMD, 1984 MAR p. 931, Eff. 6/15/84; AMD, 1987 MAR p. 1095, Eff. 7/17/87.