312 IAC 25-6-101 Underground mining; coal mine waste banks; refuse piles; water control measures

Sec. 101. Refuse piles shall meet the requirements of section 99 of this rule, 30 CFR 77.214, 30 CFR 77.215, and the following: (1) Drainage control shall be provided as follows: (A) If the disposal area contains springs, natural or manmade water courses, or wet weather seeps, the design shall include diversions and underdrains as necessary to control erosion, prevent water infiltration into the disposal facility, and ensure stability. (B) Uncontrolled surface drainage may not be diverted over the outslope of the refuse piles. Run-off from the areas above the refuse pile and run-off from the surface of the refuse pile shall be diverted into stabilized diversion channels designed to meet the requirements of section 78 of this rule to safely pass the run-off from a one hundred (100) year, six (6) hour precipitation event. Run-off diverted from undisturbed areas need not be commingled with run-off from the surface of the refuse pile. (C) Underdrains shall comply with the requirements of section 102 of this rule. (2) Slope protection shall be provided to minimize surface erosion at the site. All disturbed areas, including diversion channels that are not riprapped or otherwise protected, shall be revegetated upon completion of construction. (3) The following are placement requirements: (A) All vegetative and organic materials shall be removed from the disposal area prior to placement of coal mine waste. Topsoil shall be removed, segregated and stored, or redistributed in accordance with section 75 of this rule. If approved by the director, organic material may be used as mulch, or may be included in the topsoil to control erosion, promote growth of vegetation, or increase the moisture retention of the soil. (B) The final configuration of the refuse pile shall be suitable for the approved postmining land use. Terraces may be constructed on the outslope of the refuse pile if required for stability, control of erosion, conservation of soil moisture, or facilitation of the approved postmining land use. The grade of the outslope between terrace benches shall not be steeper than 2h:1v (fifty percent (50%)). (C) No permanent impoundments shall be allowed on the completed refuse pile. Small depressions may be allowed by the director if they are not incompatible with the stability of the refuse pile and if they are needed to: (i) retain moisture; (ii) minimize erosion; (iii) create and enhance wildlife habitat; or (iv) assist revegetation. (D) Following final grading of the refuse pile, the coal mine waste shall be covered with a minimum of four (4) feet of the best available, nontoxic and noncombustible earthen material, in a manner that does not impede drainage from the underdrains. The director may allow less than four (4) feet of cover material based on physical and chemical analyses which show that the requirements of sections 115 through 122 of this rule will be met.