16 Tex. Admin. Code § 12.531 - Disposal of Underground Development Waste and Excess Spoil: General Requirements
(a) Underground
development waste and spoil not required to achieve the approximate original
contour and which is not used as backfill shall be hauled or conveyed to and
placed in designated disposal areas within a permit area if the disposal areas
are authorized for such purposes in the approved permit application in
accordance with this section and §§
12.532-12.534 of this title (relating to
Disposal of Underground Development Waste and Excess Spoil: Valley Fills, to
Disposal of Underground Development Waste and Excess Spoil: Head-of-Hollow
fills, and to Disposal of Underground Development Waste and Excess Spoil:
Durable Rock Fills). The material shall be placed in a controlled manner to
ensure:
(1) that leachate and surface runoff
from the fill will not degrade surface or ground waters or exceed the effluent
limitations referenced in §
12.510 of this title (relating to
Hydrologic Balance: Water-Quality Standards and Effluent
Limitations);
(2) stability of the
fill; and
(3) that the land mass
designated as the 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 professional
engineer, and approved by the Commission.
(c) All vegetative and organic materials
shall be removed from the disposal area and the topsoil shall be removed,
segregated and stored or replaced in accordance with §§
12.504-12.508 of this title (relating to
Topsoil: General Requirements, to Topsoil: Removal, to Topsoil: Storage, to
Topsoil: Redistribution, and to Topsoil: Nutrients and Soil Amendments). If
approved by the Commission, 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. Diversion design shall conform with the
requirements of §
12.511 of this title (relating to
Hydrologic Balance: Diversions). All disturbed areas, including diversion
ditches that are not riprapped, 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 Commission. If such 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.
(f) The fill materials shall
be hauled or conveyed and placed in horizontal lifts in a controlled manner,
concurrently compacted as necessary to ensure mass stability and prevent mass
movement, covered, 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.
(g) The final
configuration of the fill must be suitable for postmining land uses approved in
accordance with §
12.568 of this title (relating to
Postmining Land Use), except that no depressions or impoundments shall be
allowed on the completed fill.
(h)
Terraces may be utilized to control erosion and enhance stability if approved
by the Commission and consistent with §
12.552(b) of
this title (relating to Backfilling and Grading: General Grading
Requirements).
(i) Where the slope
in the disposal area exceeds 2.8h:1v (36%), or such lesser slope as may be
designated by the Commission 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 §
12.183 of this title (relating to
Cross Sections, Maps, and Plans) to determine the size of the rock
toe-buttresses or keyway cuts.
(j)
The fill shall be inspected for stability by a qualified professional engineer
experienced in the construction of earth and rockfill embankments at least
quarterly throughout construction, and during the following critical
construction periods:
(1) removal of all
organic material and topsoil;
(2)
placement of underdrainage systems and protective filter systems;
(3) installation of surface drainage
systems;
(4) placement and
compaction of fill materials; and
(5) revegetation.
(k) The qualified professional engineer shall
provide to the Commission a certified report, within two weeks after each
inspection that the fill has been constructed as specified in the design
approved by the Commission. 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. A copy of the report shall be retained at the minesite.
(l) Coal mine waste shall not be disposed of
in valley or head-of-hollow fills and may only be disposed of with underground
development waste, or in other excess spoil fills, if such waste is:
(1) placed in accordance with §
12.538 of this title (relating to
Coal Mine Waste Banks: Construction Requirements);
(2) demonstrated to be non-toxic and non-acid
forming; and
(3) demonstrated to be
consistent with the design stability of the fill.
(m) If the disposal area contains springs,
natural or manmade watercourses, 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. Where excess
durable rock spoil is placed in single or multiple lifts such that the
underdrain system is constructed simultaneously with excess spoil placement by
the natural segregation of dumped materials, color photographs shall be taken
of the underdrain as the underdrain system is being formed.
(n) The foundation and abutments of the fill
shall be stable under all conditions of construction and operation. Sufficient
foundation investigations 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.
(o) Underground
development waste and excess spoil may be returned to underground workings only
in accordance with the disposal plans submitted under §
12.193 of this title (relating to
Underground Development Waste/Return of Coal Processing Waste to Abandoned
Underground Workings) and approved by the Commission and MSHA.
(p) Excess spoil that is acid-forming or
toxic-forming or combustible shall be adequately covered with non-acid,
non-toxic and noncombustible material, or treated, to control the impact on
surface and ground water in accordance with this chapter (relating to Coal
Mining Regulations), to prevent sustained combustion, and to minimize adverse
effects on plant growth and the approved postmining land use.
(q) The photographs required by this section
to accompany 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.
Notes
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