Authority: IC 14-34-2-1

Affected: IC 14-34

Sec. 138. (a) Auger mining associated with surface mining activities shall be conducted to maximize recoverability of mineral reserves remaining after the mining activities are completed. Each person who conducts auger mining operations shall leave areas of the undisturbed coal to provide access for removal of those reserves by future underground mining activities, unless the director determines that the coal reserves have been depleted or are limited in thickness or extent to the point that it will not be practicable to recover the remaining coal reserves. The director shall make this determination only upon presentation of appropriate technical evidence by the operator. Undisturbed areas of coal shall be left in unmined sections that satisfy each of the following:

1. (1) Are a minimum of two hundred fifty (250) feet wide at any point between each group of auger openings to the full depth of the auger hole.
2. (2) Are no more than two thousand five hundred (2,500) feet apart, measured from the center of one (1) section to the center of the next section, unless a greater distance is set forth in the permit application under 312 IAC 25-4-104 and approved by the director.
3. (3) For multiple seam mining, have a width of at least two hundred fifty (250) feet plus fifty (50) feet for each subjacent workable coal seam. The centers of all unmined sections shall be aligned vertically.

(b) No auger hole shall be made closer than five hundred (500) feet in horizontal distance to any abandoned or active underground mine workings, except as approved under section 35 of this rule.

(c) Except as provided in subsection (d), to prevent the pollution of surface and ground water and to reduce fire hazards, each auger hole shall be plugged to prohibit the discharge of water from the hole and access of air to the coal as follows:

1. (1) Each auger hole that discharges water containing toxic-forming or acid-forming material shall be sealed within seventy-two (72) hours after completion with noncombustible and impervious material. If sealing within seventy-two (72) hours is not possible, the discharge shall be treated within seventy-two (72) hours after completion to meet applicable effluent limitations and water quality standards until the hole is sealed.
2. (2) Each auger hole that does not discharge water containing toxic-forming or acid-forming material shall be sealed under subdivision (1) to close the opening as contemporaneously as practicable with the auguring operation in accordance with a schedule approved by the director in the approved permit.

(d) An auger hole need not be plugged if the director finds the following:

1. (1) The impoundment of water that would result from plugging the hole may create a hazard to the environment or to public health or safety.

2. (2) The drainage from the auger hole will achieve each of the following:

   1. (A) It will not pose a threat of pollution to surface water.
   2. (B) It will comply with the requirements of sections 12 and 13 of this rule.

(e) The director shall prohibit auger mining if it is determined that any of the following may occur:

1. (1) Adverse water quality impacts cannot be prevented or corrected.
2. (2) Fill stability cannot be achieved.
3. (3) The prohibition is necessary to maximize the utilization, recoverability, or conservation of the solid fuel resources.
4. (4) Subsidence resulting from auger mining may disturb or damage power lines, pipelines, buildings, or other facilities.

(Natural Resources Commission; 312 IAC 25-6-138; filed Jun 21, 2001, 2:53 p.m.: 24 IR 3584, eff Dec 1, 2001; errata filed Nov 20, 2001, 11:55 a.m.: 25 IR 1182; readopted filed May 29, 2007, 9:51 a.m.: 20070613-IR-312070146RFA; readopted filed Sep 19, 2013, 10:12 a.m.: 20131016-IR-312130125RFA; readopted filed Mar 26, 2019, 3:40 p.m.: 20190424-IR-312190011RFA; readopted filed Mar 25, 2025, 9:50 a.m.: 20250423-IR-312240574RFA)