405 KAR 16:190 - Backfilling and grading
RELATES TO: KRS 350.020, 350.093, 350.100, 350.405, 350.410, 350.450, 350.465, 30 C.F.R. Parts 730-733, 735, 816.102 -.106, 917, 30 U.S.C. 1253, 1255, 1265
NECESSITY, FUNCTION, AND CONFORMITY: KRS Chapter 350 in pertinent part requires the cabinet to promulgate rules and administrative regulations establishing performance standards for protection of people and property, land, water and other natural resources, and aesthetic values, during surface mining activities and for restoration and reclamation of surface areas affected by mining activities. This administrative regulation sets forth requirements for backfilling and grading, including requirements for highwall elimination, return to approximate original contour, timing of backfilling and grading, use of terraces, thick and thin overburden conditions, covering coal and acid and toxic materials, and regrading or stabilizing rills and gullies.
Section 1. Timing of
Backfilling and Grading. Backfilling and grading shall be conducted in
accordance with the requirements for contemporaneous reclamation as set forth
in
405 KAR 16:020.
Section
2. General Backfilling and Grading Requirements.
(1) Except as provided in subsection (9) of
this section, all disturbed areas shall be returned to their approximate
original contour. All spoil shall be transported, placed in a controlled
manner, backfilled, compacted (where advisable to ensure stability or to
prevent leaching of toxic materials), and graded to:
(a) Eliminate all highwalls (except as
otherwise provided in Section 7 of this administrative regulation), spoil
piles, and depressions (excluding depressions and impoundments approved
pursuant to subsection (5) or (6) of this section);
(b) Ensure a long-term static factor of
safety of at least one and three-tenths (1.3) for all portions of the reclaimed
land;
(c) Achieve a postmining
slope which does not exceed the angle of repose and which does prevent
slides;
(d) Minimize erosion and
adverse effects on surface and ground water both on and off the site;
and
(e) Support the approved
postmining land use.
(2)
Spoil, except excess spoil disposed of in accordance with
405 KAR 16:130, shall be returned to the excavated
areas.
(3) Disposal of coal
processing waste and underground development waste in the mined-out area shall
be in accordance with
405 KAR 16:140, except that a long-term static safety factor
of one and three-tenths (1.3) shall be achieved.
(4) On approval by the cabinet in order to
conserve soil moisture, ensure stability, and control erosion on final graded
slopes, cut-and-fill terraces may be allowed, if the terraces are compatible
with the approved postmining land use and are appropriate substitutes for
construction of lower grades on the reclaimed lands. The terraces shall meet
the following requirements:
(a) The width of
the individual terrace bench shall not exceed twenty (20) feet, unless
specifically approved by the cabinet as necessary for stability, erosion
control, or roads included in the approved postmining land use plan.
(b) The vertical distance between terraces
shall be as specified by the cabinet, to prevent excessive erosion and to
provide long-term stability.
(c)
The slope of the terrace outslope shall not exceed 1v:2h (fifty (50) percent).
Outslopes which exceed 1v:2h (fifty (50) percent) may be approved, if they have
a minimum static safety factor of more than 1.3, provide adequate control over
erosion, and closely resemble the surface configuration of the land prior to
mining. In no case may highwalls be left as part of terraces.
(d) Culverts and underground rock drains
shall be used on the terrace only if approved by the cabinet.
(5) Small depressions may be
constructed on backfilled areas, if the depressions:
(a) Are needed to minimize erosion, conserve
soil moisture, create or enhance wildlife habitat, or promote
vegetation;
(b) Are not disapproved
by the cabinet;
(c) Are not
substitutes for compliance with approximate original contour
requirements;
(d) Do not adversely
affect the stability of the backfilled area; and
(e) Are not located on steep-slope
outslopes.
(6)
Impoundments on backfilled areas may be approved, if the impoundments:
(b) Are demonstrated, to the satisfaction of
the cabinet in the permit application, to have no adverse effect on the
stability of the backfilled area;
(c) Are consistent with and suitable for the
approved postmining land use;
(d)
Are specifically approved by the cabinet in the permit application;
and
(e) Are not located on
steep-slope outslopes.
(7) All surface mining activities on slopes
above twenty (20) degrees, or on lesser slopes that the cabinet defines as
steep slopes, shall comply with the requirements of
405 KAR 20:060.
(8) All final grading; preparation of
overburden before replacement of topsoil, topsoil substitutes, and topsoil
supplements; and placement of topsoil, topsoil substitutes, and topsoil
supplements shall be done along the contour to minimize subsequent erosion and
instability. If grading, preparation, or placement along the contour is
hazardous to equipment operators, then grading, preparation, and placement in a
direction other than generally parallel to the contour may be used. In all
cases, grading, preparation, or placement shall be conducted in a manner which
minimizes erosion and provides a surface for placement of topsoil, topsoil
substitutes, and topsoil supplements which will minimize slippage.
(9) The postmining slope may vary from the
approximate original contour if approval is obtained from the cabinet for:
(a) The provisions for thin overburden in
Section 4 of this administrative regulation;
(b) The provisions for thick overburden in
Section 5 of this administrative regulation;
(c) Mountaintop removal operations in
accordance with
405 KAR 8:050, Section 4;
(d) A variance from approximate original
contour requirements in accordance with
405 KAR 8:050, Section 6; or
(e) Incomplete elimination of highwalls in
previously mined areas in accordance with Section 7 of this administrative
regulation.
Section
3. Disposal of Acid-forming, Toxic-forming, and Combustible
Materials and Coverage of Coal Seams.
(1)
General. Exposed coal seams, acid-forming materials, toxic-forming materials,
and combustible materials which are used, produced, or exposed during surface
coal mining and reclamation operations shall be handled; disposed of; treated;
and covered with nontoxic-forming, nonac-id-forming, and noncombustible
materials in a manner which:
(a) Minimizes
adverse impacts on surface and ground water, minimizes disturbances to the
hydrologic balance, and prevents material damage to the hydrologic
balance;
(b) Ensures compliance
with
405 KAR 16:060;
(c) Prevents sustained combustion;
(d) Minimizes adverse impacts on plant growth
and the approved postmining land use;
(e) Ensures that the affected area is capable
of sustaining sufficient vegetation to meet the re-vegetation requirements of
405 KAR 16:200;
and
(f) Ensures that the affected
area is capable of meeting the postmining land use requirements of
405 KAR 16:210.
(2) Coverage and treatment. All exposed coal
seams, acid-forming materials, toxic-forming materials, and combustible
materials which are used, produced, or exposed during surface coal mining and
reclamation operations shall be covered and treated as necessary to neutralize
toxicity, acidity, and combustibility, in order to ensure long-term and
short-term compliance with subsection (1) of this section.
(a) All exposed coal seams shall be covered
with a minimum of four (4) feet of nontoxic-forming, nonacid-forming, and
noncombustible materials. The cabinet shall require thicker amounts of cover,
special compaction of cover, treatment, or other measures as necessary to
ensure compliance with subsection (1) of this section and to prevent exposure
of the coal seams by erosion.
(b)
Excluding exposed coal seams, all acid-forming materials, toxic-forming
materials, and combustible materials which are used, produced, or exposed
during surface coal mining and reclamation operations shall be:
1. Selectively blended with nontoxic-forming,
nonacid-forming, and noncombustible materials; treated; or selectively handled,
or an appropriate combination of those measures shall be used, as necessary to
ensure compliance with subsection (1) of this section; and
2. Covered with a minimum of four (4) feet of
nontoxic-forming, nonacid-forming, and noncom-bustible materials. The cabinet
shall require thicker amounts of cover, special compaction of cover, treatment,
or other measures as necessary to ensure compliance with subsection (1) of this
section and to prevent exposure of the toxic-forming, acid-forming, or
combustible materials by erosion. The cabinet may approve lesser amounts of
cover, or no cover (other than topsoil, topsoil substitutes, or topsoil
supplements), if the applicant demonstrates, to the satisfaction of the cabinet
in the permit application, that the lesser amounts are sufficient to ensure
compliance with subsection (1) of this section and to maintain coverage of the
toxic-forming, acid-forming, and combustible materials;
3. If required or approved by the cabinet,
compacted and placed in an environment which minimizes the oxidation potential
of the toxic-forming materials, acid-forming materials, and combustible
materials; and
4. If required or
approved by the cabinet, disposed so as to minimize surface and ground water
contact with acid-forming materials, toxic-forming materials, and combustible
materials. Water contact may be minimized by the encasement of those materials
in low-permeability substances and by the compaction and selective placement of
those materials in locations other than surface drainage courses, ground water
recharge areas, or areas of significant ground water flow. As an alternative to
minimizing contact with surface and ground water and if feasible based on site
conditions, the cabinet may allow acid-forming materials, toxic-forming
materials, and combustible materials to be placed below the permanent water
table.
(3)
The cabinet shall require measures in addition to those identified in
subsection (2) of this section if necessary to ensure protection of the
environment or the health or safety of the public.
Section 4. Thin Overburden.
(1) The provisions of this section apply only
where the final thickness is less than eight-tenths (0.8) of the initial
thickness. Initial thickness is the sum of the overburden thickness and coal
thickness prior to removal of coal. Final thickness is the product of the
overburden thickness prior to removal of coal times the bulking factor to be
determined for each permit area. The provisions of this section apply only if
surface mining activities cannot be carried out to comply with Section 2 of
this administrative regulation to achieve the approximate original
contour.
(2) In surface mining
activities carried out continuously in the same limited pit area for more than
one (1) year from the day coal removal operations begin and where the volume of
all available spoil and suitable waste materials over the permit area is
demonstrated to be insufficient to achieve the approximate original contour of
the lands disturbed, surface mining activities shall be conducted to meet, at a
minimum, the following standards:
(a)
Transport, backfill, and grade, using all available spoil and suitable waste
materials from the entire mine area, to attain the lowest practicable stable
grade, to achieve a static safety factor of 1.3, and to provide adequate
drainage and long-term stability of the regraded areas and cover all
acid-forming and toxic-forming materials;
(b) Eliminate highwalls by grading or
backfilling to stable slopes not exceeding 1v:2h (fifty (50) percent), or to
lesser slopes as the cabinet may specify to reduce erosion, maintain the
hydrologic balance, or allow the approved postmining land use;
(c) Transport, backfill, grade, and
revegetate in accordance with
405 KAR 16:200, to
achieve an ecologically sound land use compatible with the prevailing use in
unmined areas surrounding the permit area; and
(d) Transport, backfill, and grade, to ensure
impoundments are constructed only if:
1. It
has been demonstrated to the cabinet's satisfaction that all requirements of
405 KAR 16:060,
405 KAR 16:070,
405 KAR 16:080,
405 KAR 16:090,
405 KAR 16:100 and
405 KAR 16:110 have been met; and
2. The impoundments have been approved by the
cabinet as suitable for the approved postmining land use and as meeting the
requirements of this chapter and all other applicable federal and state laws
and regulations.
Section 5. Thick Overburden.
(1) The provisions of this section apply only
where the final thickness is greater than one and two-tenths (1.2) of the
initial thickness. Initial thickness is the sum of the overburden thickness and
coal thickness prior to removal of coal. Final thickness is the product of the
overburden thickness prior to removal of coal times the bulking factor to be
determined for each permit area. The provisions of this section apply only if
surface mining activities cannot be carried out to comply with Section 2 of
this administrative regulation to achieve the approximate original
contour.
(2) In surface mining
activities where the volume of spoil over the permit area is demonstrated to be
more than sufficient to achieve the approximate original contour, surface
mining activities shall be conducted to meet, at a minimum, the following
standards:
(a) Transport, backfill, and grade
all spoil and wastes, not required to achieve the approximate original contour
of the permit area, to the lowest practicable grade, to achieve a static factor
of safety of one and three-tenths (1.3) and cover all acid-forming and other
toxic-forming materials;
(b)
Transport, backfill and grade excess spoil and wastes only within the permit
area and dispose of those materials in accordance with
405 KAR 16:130;
(c) Transport, backfill, and grade excess
spoil and wastes to maintain the hydrologic balance, in accordance with
405 KAR 16:060,
405 KAR 16:070,
405 KAR 16:080,
405 KAR 16:090,
405 KAR 16:100 and
405 KAR 16:110 and to provide long-term stability by
preventing slides, erosion and water pollution;
(d) Transport, backfill, grade, and
revegetate wastes and excess spoil to achieve an ecologically sound land use
approved by the cabinet as compatible with the prevailing land uses in unmined
areas surrounding the permit area;
(e) Eliminate all highwalls and depressions
by backfilling with spoil and suitable waste materials; and
(f) Meet the revegetation requirements of
405 KAR 16:200 for
all disturbed areas.
Section 6. Regrading or Stabilizing Rills and
Gullies. Except as provided in subsections (a) and (b) of this section, if
rills or gullies deeper than nine (9) inches form in areas that have been
regraded and topsoiled, the rills and gullies shall be filled, graded, or
otherwise stabilized and the area re-seeded and replanted according to
405 KAR 16:200.
(1) Rills or gullies less than nine (9)
inches deep shall be stabilized and the area reseeded and replanted, if the
rills or gullies are disruptive to the approved postmining land use or to the
establishment of vegetation, may result in additional erosion and
sedimentation, or may cause or contribute to the violation of a water quality
standard.
(2) Rills and gullies
deeper than nine (9) inches need not be filled, regraded, and revegetated if
all of the following criteria are met:
(a)
They are incised to solid bedrock or are otherwise stable and not likely to
further erode;
(b) They are not
disruptive to the approved postmining land use or to the establishment of the
vegetative cover; and
(c) They
neither cause nor contribute to the violation of water quality
standards.
Section
7. Remining Previously Mined Areas.
(1) General requirements. Remining operations
on previously mined areas, including steep slope areas, that contain a
preexisting highwall shall comply with Sections 1 through 6 of this
administrative regulation except as provided in this section.
(2) Variances to backfilling and grading
requirements for remining operations. The requirements within Section 2(1)(a)
of this administrative regulation to completely eliminate highwalls shall apply
to remining operations, except for situations in which the volume of all
reasonably available spoil is demonstrated, to the satisfaction of the cabinet
in the permit application, to be insufficient to completely backfill and
eliminate the preexisting or modified highwall. The highwall shall be
eliminated to the maximum extent technically practicable in accordance with the
following criteria:
(a) All reasonably
available spoil shall be used to backfill the area.
(b) The backfill shall be graded to a slope
which is compatible with the approved postmining land use and which provides
adequate drainage and long-term stability (one and three-tenths (1.3) long-term
static factor of safety). The exposed coal seam shall be covered in accordance
with Section 3 of this administrative regulation.
(c) Spoil generated or handled by the
remining operation shall not be placed on the fill section of any existing or
new bench.
(d) Any highwall remnant
shall be stable and not pose a hazard to the public health and safety or to the
environment. The permittee shall demonstrate, to the satisfaction of the
cabinet in the permit application, that the postmining highwall remnant will be
stable. If the highwall remnant is determined by the cabinet to be unstable or
potentially unstable, the permittee shall perform any corrective measures
required by the cabinet to stabilize the highwall remnant.
(e) Spoil placed on the outslope during
previous mining operations shall not be disturbed if the disturbance will cause
instability of the remaining spoil or otherwise increase the hazard to the
public health or safety or to the environment.
Notes
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