Illinois Administrative Code
Title 62 - MINING
Part 1816 - PERMANENT PROGRAM PERFORMANCE STANDARDS - SURFACE MINING ACTIVITIES
Section 1816.71 - Disposal of Excess Spoil: General Requirements
Current through Register Vol. 48, No. 12, March 22, 2024
a) Excess spoil shall be placed in designated disposal areas within a permit area, in a controlled manner to:
b) Design certification.
c) All vegetative and organic materials shall be removed from the disposal area prior to placement of the excess spoil. Topsoil shall be removed, segregated, and stored or replaced in accordance with Section 1816.22. If approved by the Department, 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.
d) 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 from erosion, shall be vegetated upon completion of construction.
e) The disposal areas shall be located on the most moderately sloping and naturally stable areas available as approved by the Department. Fill materials suitable for disposal shall be placed upon or above a natural terrace, bench or berm if such placement provides additional stability and prevents mass movement.
f) Excess spoil shall be transported and placed in a controlled manner in horizontal lifts not exceeding four (4) feet in thickness, concurrently compacted as necessary to ensure mass stability and prevent mass movement during and after construction; graded so that surface and subsurface drainage is compatible with the natural surroundings; and covered with topsoil or substitute material in accordance with Section 1816.22. The Department may approve a design which incorporates placement of excess spoil in horizontal lifts other than four (4) feet in thickness when it is demonstrated by the operator and sealed by a qualified registered professional engineer that the design will ensure the stability of the fill and will meet all other requirements of this Section.
g) The final configuration of the fill must be suitable for the approved post-mining land use. In addition:
h) 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 post-mining land use, as set forth in Sections 1816.41(a) and 1816.111(a). The grade of the outslope between terrace benches shall not be steeper than 2h:1v (fifty (50) percent). Terrace(s) are required where the vertical height of the excess spoil exceeds forty (40) feet.
i) Where the slope in the disposal area exceeds lv:2.8 h (thirty-six (36) percent), or such lesser slope designated by the Department based on local conditions, keyway cuts (excavations to stable bedrock) or rock toe buttresses shall be constructed to stabilize the fill. Where the toe of the spoil rests on a downslope, stability analyses shall be performed in accordance with 62 Ill. Adm. Code 1780.35(c) to determine the size of rock toe buttresses and keyway cuts.
j) A qualified registered professional engineer or other qualified professional specialist under the direction of a registered professional engineer, experienced in the construction of earth and rockfill embankments, shall periodically inspect the fill during construction. Such inspections shall be made at least quarterly throughout construction and during the critical construction periods. Critical construction periods shall include at a minimum:
k) Coal processing wastes shall not be disposed of in head-of-hollow or valley fills, and may only be disposed of in other excess spoil fills, if such waste is:
l) Drainage control. If the disposal area contains springs, natural or manmade watercourses, or wet-weather seeps, the fill design shall include diversions and underdrains as necessary to control erosion, prevent water infiltration into the fill, and ensure stability.
m) The foundation and abutments of the fill shall be stable under all conditions of construction and operation. Sufficient foundation investigation, as well as any necessary 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 fill and appurtenant structures.
n) Excess spoil may be returned to underground mine workings, but only in accordance with a disposal program approved by the Department and MSHA under 62 Ill. Adm. Code 1784.25.
o) Excess spoil that is acid- 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 Section 1816.41, to prevent sustained combustion, and to minimize adverse effects on plant growth and the approved post-mining land use as set forth in Section 1816.111(a).