§ 90.122. Coal refuse disposal.
(a) Coal refuse shall be transported and placed in designated disposal areas approved by the Department for this purpose. These areas shall be within the permit area. The coal refuse disposal area shall be designed, constructed and maintained to ensure:
(1) The leachate and surface runoff from the permit area will not degrade surface water or groundwater or exceed the effluent limitations of § 90.102 (relating to hydrologic balance: water quality standards, effluent limitations and best management practices).
(2) Prevention of combustion.
(3) Prevention of public health hazards.
(4) Stability of the fill.
(5) The land mass designated as the coal refuse disposal area is suitable for reclamation and revegetation compatible with the natural surroundings.
(b) The fill shall be designed using recognized professional standards, certified by a qualified registered professional engineer, and approved by the Department.
(c) The foundation and abutment of the fill shall be stable under all conditions of construction and operation. Sufficient foundation investigations and laboratory testing of foundation materials and coal refuse shall be performed to determine the design requirements for stability of the facility. Analyses of foundation conditions shall include the effect of underground mine workings, if any, upon the stability of the structure.
(d) The coal refuse disposal fill shall be designed to attain a minimum long-term static factor of safety of 1.5 and a minimum seismic factor of safety of 1.2, based upon data obtained from subsurface exploration, geotechnical testing, foundation design, fill design and accepted engineering analyses.
(e) When the average slope of coal refuse disposal area exceeds lv:2.8h—36%, or lesser slopes as may be designated by the Department based on local conditions, key way cuts, or excavation into stable bedrock or bedrock toe buttresses shall be constructed to stabilize the fill. When the toe of the fill rests on a downslope, stability analysis shall be performed in accordance with § 90.39 (relating to ponds, impoundments, banks, dams, embankments, piles and fills) to determine the size of rock toe buttresses and key way cuts.
(f) If the disposal area contains springs, natural or manmade watercourses, or wet-weather seeps, the Department may approve an underdrain/subdrainage system, consisting of durable rock or other materials, designed and placed in a manner that prevents infiltration of the water into the fill material and ensures continued free drainage from the wet areas.
(g) The disposal area shall be provided with a system to prevent adverse impacts to the surface water and groundwater. The system shall be constructed in accordance with design schematics, test results, descriptions, plans, maps, profiles or cross-sections approved in the permit and shall function to prevent adverse impacts to surface water and groundwater.
(h) The operator shall install a system to prevent precipitation from coming in contact with the coal refuse. The system shall be constructed in accordance with the design schematics, test results, descriptions, plans, maps, profiles or cross-sections approved in the permit, and designed to allow for revegetation of the site in accordance with the standard of success under § 90.159 (relating to revegetation: standards for successful revegetation) and for the prevention of erosion:
(1) [Reserved].
(2) [Reserved].
(3) [Reserved].
(4) [Reserved].
(5) as phases reach capacity;
(6) as specified in the permit;
(7) if the operator temporarily ceases operation of the coal refuse disposal area for a period in excess of 90 days, unless the Department approves an operator’s request for a longer period for the installation of the system; or
(8) when the operation permanently ceases.
(i) An underdrain/subdrainage system for the fill shall be designed in accordance with the following:
(1) It shall include an underdrain system which will ensure continued free drainage of anticipated seepage from precipitation and from spring or wet-weather seeps, and meet the following:
(i) Anticipated discharges from springs and seeps due to precipitation shall be based on records or field investigation or both, to determine seasonal variation. The design of the underdrain system shall be based on maximum anticipated discharges.
(ii) Granular material used for the drainage system shall be nondegradable, nonacid-forming or nontoxic-forming rock free of clay, and consist of durable particles such as natural sands and gravels, sandstone, limestone or other durable rock which will not flake in water.
(2) The underdrain system shall be designed to be installed along the natural drainage system; extend from toe to head of fill; and contain lateral drains to each area of potential drainage or seepage.
(3) A filter system to ensure the proper functioning of the rock underdrain system shall be designed and constructed using standard geotechnical engineering methods.
(j) The final configuration of the fill shall be suitable for the post disposal land use approved under § 90.165 (relating to prime farmland: revegetation), except that no depression or impoundment may be allowed on the completed fill. New coal refuse disposal piles and area of piles active since May 17, 1973, shall blend into the local surroundings. Unless otherwise approved by the Department, the fill may not be designed to exceed the approximate elevation of the surrounding ridgeline.
(k) The maximum overall completed slope of the coal refuse disposal pile measured from toe of the fill to crest of upper terrace may not exceed 33% or 18 degrees.
(l) The top surface of the completed fill shall be graded so that the final slope after settlement will be no steeper than lv:20h—5.0% toward properly designed drainage channels in natural ground along the periphery of the fill. Surface runoff from the top surface of the fill may not be allowed to flow over the outslope of the fill.
(m) Terraces must be utilized to control erosion and enhance stability, and may be utilized for roads included in postmining land use.
(1) The slope of the outslope between terraces may not exceed lv:2h—50%. The vertical distance between terraces may not exceed 50 feet.
(2) To control surface runoff, each terrace bench will be a minimum of 20 feet wide, shall be graded to a slope of lv:20h—5.0% toward the embankment. Runoff shall be collected by a ditch along the intersection of each terrace bank and the toe of the next higher outslope.
(3) Terrace ditches shall have a maximum 5.0% slope toward the channels specified in subsection (o) unless steeper slopes are necessary in conjunction with approved roads.
(n) Surface water runoff from areas adjacent to and above the fill shall be diverted away from the fill in stabilized channels which are designed to safely pass the peak runoff from a 100-year precipitation event. Diversion channels shall also comply with § 90.104(a) and (c)—(h) (relating to hydrologic balance: diversions).
(o) Surface water runoff from the fill shall be collected and conveyed in properly designed channels constructed in natural ground or engineered fill of inert material along the periphery of the fill. The channels must safely pass the peak runoff from a 100-year precipitation event.
(p) Slope protection shall be provided to minimize surface erosion at the site. Disturbed areas, including diversion ditches that are not riprapped, shall be vegetated upon completion of construction.
(q) Coal refuse shall be hauled or conveyed and placed in a controlled manner and concurrently compacted as approved by the Department in lifts no greater than 2 feet, or less, as required or approved by the Department, as the design to:
(1) Achieve the densities designed to ensure mass stability.
(2) Prevent mass movement.
(3) Avoid contamination of the rock underdrain.
(4) Prevent formation of voids.
(r) Vegetative and organic materials shall be removed from the area where coal refuse is disposed of, and for a distance of 50 feet from the perimeter of the area where coal refuse is disposed, the topsoil shall be removed, segregated and stored or replaced as provided in § § 90.96—90.100. If approved by the Department, organic material may be used a mulch or may be included in the topsoil to control erosion, promote growth of vegetation or increase the moisture retention of the soil.
Authority The provisions of this § 90.122 amended under the Surface Mining Conservation and Reclamation Act (52 P. S. § § 1396.1—1396.19a); The Clean Streams Law (35 P. S. § § 691.1—691.1001); section 1920-A of The Administrative Code of 1929 (71 P. S. § 510-20); and section 3.2 of the Coal Refuse Disposal Control Act (53 P.S. § 30.53b).
Source The provisions of this § 90.122 adopted December 19, 1980, 10 Pa.B. 4789, effective July 31, 1982, 12 Pa.B. 2382; amended July 30, 1982, 12 Pa.B. 2473, effective July 31, 1982, 12 Pa.B. 2382; amended June 15, 1990, 20 Pa.B. 3383, effective July 27, 1991, 21 Pa.B. 3316; amended December 15, 1995, effective December 16, 1995, 25 Pa.B. 5821; amended July 13, 2001, effective July 14, 2001, 31 Pa.B. 3735; amended September 9, 2022, effective September 10, 2022, 52 Pa.B. 5804. Immediately preceding text appears at serial pages (405024) and (281261) to (281263).
Cross References This section cited in 25 Pa. Code § 87.73 (relating to dams, ponds, embankments and impoundments); 25 Pa. Code § 90.39 (relating to ponds, impoundments, banks, dams, embankments, piles and fills); 25 Pa. Code § 90.111 (relating to hydrologic balance: impoundments); 25 Pa. Code § 90.113 (relating to hydrologic balance: coal processing waste dams and embankments); 25 Pa. Code § 90.120 (relating to hydrologic balance: permanent postdisposal renovation of sedimentation ponds, diversions, impoundments and treatment facilities); 25 Pa. Code § 90.125 (relating to coal refuse disposal: construction requirements); 25 Pa. Code § 90.130 (relating to coal refuse dams); and 25 Pa. Code § 90.164 (relating to prime farmland: soil replacement).
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