Chapter 26. Excess Spoil Disposal

Except as provided in Regulation .05 of this chapter, excess spoil shall be placed in designated disposal areas within the permit area in a controlled manner to:

The fill and appurtenant structures shall be designed using current, prudent engineering practices and shall meet any design criteria established by the Bureau. A qualified registered professional engineer experienced in the design of earth and rock fills shall certify the design of the fill and appurtenant structures.

All vegetative and organic materials shall be removed from the disposal area and disposed of in an approved manner and location. All topsoil shall be removed and handled in accordance with COMAR 26.20.25.02.

Slope protection shall be provided to minimize surface erosion at the site. All disturbed areas, including diversion ditches that are not riprapped, shall be vegetated upon completion of construction.

The disposal areas shall be located on the most moderately sloping and naturally stable areas available as approved by the Bureau. If the placement provides additional stability and prevents mass movement, fill materials suitable for disposal shall be placed upon or above a natural terrace, bench, or berm.

The spoil shall be hauled or conveyed and placed in horizontal lifts not exceeding 4 feet in thickness in a controlled manner, concurrently compacted as necessary to ensure mass stability and prevent mass movement during and after construction, covered with topsoil or substitute material, and graded to allow surface and subsurface drainage to be compatible with the natural surroundings and ensure a long-term static safety factor of 1.5. The Bureau may approve a design which incorporates placement of excess spoil in horizontal lifts other than 4 feet in thickness when it is demonstrated by the operator and certified by a qualified registered professional engineer that the design will ensure the stability of the fill and will meet all other applicable requirements.

The final configuration of the fill shall be suitable for postmining land uses approved in accordance with the permit, except that no depressions or impoundments shall be allowed on the completed fill.

Terraces may be constructed on the outslope of the fill if required for stability, control of erosion, to conserve soil moisture, or to facilitate the approved postmining land use. The grade of the outslope between terrace benches may not be steeper than 2:1 (50 percent).

If the slope in the disposal area exceeds 2.8:1 keyway cuts (excavations to stable bedrock) or rock toe buttress shall be constructed to stabilize the fill. If the toe of the spoil rests on a downslope, stability analyses shall be performed to determine the size of rock toe buttresses and keyway cuts.

Excess spoil that is acid-forming or toxic-forming or combustible shall be adequately covered with nonacid, nontoxic and noncombustible material, or treated to control the impact on surface and ground water in accordance with COMAR 26.20.20, to prevent sustained combustion, and to minimize adverse effects on plant growth and the approved postmining land use.

A qualified registered professional engineer, or other qualified professional specialist under the direction of the professional engineer, shall periodically inspect the fill during construction. The professional engineer or specialist shall be experienced in the construction of earth and rock fills.

The inspections shall be made at least quarterly throughout construction and during critical construction periods. Critical construction periods shall include at a minimum:

Regular inspections by the engineer or specialist shall also be conducted during placement and compaction of fill materials.

The qualified registered professional engineer shall provide a certified report to the Bureau promptly after each inspection stating that the fill has been constructed and maintained as designed and in accordance with the approved plan and this chapter. The report shall include:

The certified report on the drainage system and protective filters shall include color photographs taken during and after construction, but before underdrains are covered with excess spoil. If the underdrain system is constructed in phases, each phase shall be certified separately.

The photographs accompanying each certified report shall be taken in adequate size and number with enough terrain or other physical features of the site shown to provide a relative scale to the photographs and to specifically and clearly identify the site.

A copy of each inspection report shall be retained at or near the mine site.

Coal processing wastes may not be disposed of in head-of-hollow or valley fills, and may only be disposed of in other excess spoil fills if the waste is:

If the disposal area contains springs, natural or man-made water courses, or wet weather seeps, an underdrain system consisting of durable rock shall be constructed from the wet areas in a manner that prevents infiltration of the water into the spoil material. The underdrain system shall be protected by an adequate filter and shall be designed and constructed using standard geotechnical engineering methods.

The foundation and abutments of the fill shall be stable under all conditions of construction and operation. Sufficient foundation investigation and laboratory testing of foundation materials shall be performed in order to determine the design requirements for stability of the foundation. Analyses of foundation conditions shall include the effect of underground mine workings, if any, upon the stability of the structure.

Excess spoil may be returned to underground mine workings, but only in accordance with a disposal program approved by the Bureau and MSHA.

Valley fills shall meet all of the general requirements for disposal of excess spoil and the additional requirements of this regulation.

The fill shall be designed to attain a long-term static safety factor of 1.5 based upon data obtained from subsurface exploration, geotechnical testing, foundation design, and accepted engineering analyses.

A subdrainage system for the fill shall be constructed in accordance with the following:

Spoil shall be hauled or conveyed and placed in a controlled manner and concurrently compacted as specified by the Bureau, in lifts not greater than 4 feet or less if required by the Bureau to:

Surface water runoff from the area above the fill shall be diverted away from the fill and into stabilized diversion channels designed to pass safely the runoff from a 100-year, 24-hour precipitation event. Surface runoff from the fill surface shall be diverted to stabilized channels off the fill which will safely pass the runoff from a 100-year, 24-hour precipitation event.

The tops of the fill and any terrace constructed to stabilize the face shall be graded no steeper than 20:1. The vertical distance between terraces may not exceed 50 feet.

Drainage may not be directed over the outslope of the fill.

The outslope of the fill may not exceed 2:1.

Disposal of spoil in a head-of-hollow fill shall meet all standards set forth in Regulations .01 and .02 of this chapter, and the additional requirements of this regulation.

The fill shall be designed to completely fill the disposal site to the approximate elevation of the ridgeline. A rock-core chimney drain may be used instead of the subdrain and surface diversion system required for valley fills. If the crest of the fill is not approximately at the same elevation as the low point of the adjacent ridgeline, the fill shall be designed as specified in valley fills, with diversion of runoff around the fill. A fill associated with contour mining and placed at or near the coal seam, and which does not exceed 250,000 cubic yards may use the rock-core chimney drain.

The alternative rock-core chimney drain system shall be designed and incorporated into the construction of head-of-hollow fills as follows:

The drainage control system shall be capable of passing safely the runoff from a 100-year, 24-hour precipitation event.

The Bureau may approve alternative methods of disposal of hard rock spoil, including fill placement by dumping in a single lift, on a site specific basis, provided the services of a registered professional engineer experienced in the design and construction of earth and rockfill embankments are used and provided the requirements of this regulation and the general requirements for disposal of excess spoil are met.

“Hard rock spoil” means rock fill consisting of at least 80 percent by volume of sandstone, limestone, or other rocks that do not slake in water. Resistance of the hard rock spoil to slaking shall be determined by using the slake index and slake durability tests in accordance with guidelines and criteria established by the Bureau.

Special Placement.

Stability Analyses.

Internal Drainage System.

Surface water runoff from the areas adjacent to and above the fill may not be allowed to flow onto the fill and shall be diverted into stabilized channels which are designed to pass safely the runoff from a 100-year, 24-hour precipitation event.

The top surface of the completed fill shall be graded so that the final slope after settlement will be no steeper than 20:1 toward properly designed drainage channels in natural ground and the periphery of the fill. Surface runoff from the top surface of fill may not be allowed to flow over the outslope of the fill.

Surface runoff from the outslope of the fill shall be diverted off the fill to properly designed channels which will pass safely a 100-year, 24-hour precipitation event.

Terraces shall be constructed on the outslope if required for control of erosion or for roads included in the approved postmining land use plan. Terraces shall meet the following requirements:

Excess spoil from a permitted coal mining operation may be placed on abandoned mine land outside of the permit area if the Department determines that the:

Reclamation Standards.

The placement of excess spoil from a permit area on abandoned mine land outside of a permit area may not be approved unless the Department finds, in writing, on the basis of information set forth in the plan or otherwise available, that:

The placement of excess spoil from a permitted coal mining operation on abandoned mine land outside of the permit area shall be accomplished in accordance with a contract between the Department and the permittee that contains conditions which:

The Department shall monitor the placement of excess spoil and the reclamation of the abandoned mine land area to ensure that the work is performed in accordance with the contract. If the operator fails to meet the terms of the contract, the Department shall issue a cessation order to stop work on the area until the failure has been corrected.