10 CSR 40-3.110 - Backfilling and Grading Requirements
(1) General.
(A) Timing of Backfilling and Grading.
1. Contour mining. Rough backfilling and
grading shall follow coal removal by not more than sixty (60) days or one
thousand five hundred (1500) linear feet. The director may grant additional
time for rough backfilling and grading if the permittee can demonstrate,
through a detailed written analysis under
10 CSR
40-6.050(8)(B) 3., that additional
time is necessary.
2. Open pit
mining with thin overburden. Rough backfilling and grading shall occur in
accordance with the time schedule approved in the permit and plan, on the basis
of the materials submitted under
10 CSR
40-6.050(8)(B) 3., which shall
specifically establish in stated increments the period between removal of coal
and completion of backfilling and grading.
3. Area strip mining. Rough backfilling and
grading either shall be-
A. Completed within
one hundred eighty (180) days following coal removal and shall not be more than
four (4) spoil ridges behind the pit being worked, the spoil from the active
pit being considered the first ridge; or
B. Not more than three (3) spoil ridges
behind the pit being worked, the spoil from the active pit being considered the
first ridge. If the pit becomes inactive for a period longer than thirty (30)
days and an alternate schedule is not approved, the pit must be backfilled and
graded within one hundred eighty (180) days of cessation of
operations.
4. Either of
the previous two (2) rough backfilling and grading schedules shall be
applicable to all areas on a mine with the backfilling and grading schedule for
each specific area identified in the permit;
5. Additional time, spoil ridges, or both,
for rough backfilling and grading may be granted by the director if the
permittee can demonstrate in a detailed written analysis, including specific
schedules and plans, that additional time or spoil ridges is
necessary.
6. Active areas such as
roads, ramps, parking areas, stockpiles and boxcut spoil, which area is shown
on an approved operations plan map, are not subject to the backfilling and
grading time frames until they become inactive or unless they are part of a
variance schedule.
(B)
Method for Backfilling and Grading.
1. Except
as specifically exempted in this chapter, all disturbed areas shall be returned
to their approximate original contour. All spoil shall be transported,
backfilled, compacted (where advisable to ensure stability or to prevent
leaching) and graded to eliminate all highwalls, spoil piles and
depressions.
2. Backfilled material
shall be placed to minimize adverse effects on groundwater, minimize off-site
effects and to support the approved post-mining land use.
3. The post-mining graded slopes need not be
of uniform slope.
4. Cut-and-fill
terraces may be used only in those situations expressly identified in section
(2) of this rule.
(2) General Grading Requirements.
(A) The final graded slopes shall not exceed
in grade either the approximate premining slopes or any lesser slopes approved
in the permit and plan based on consideration of soil, climate or other
characteristics of the surrounding area. Post-mining final graded slopes need
not be uniform but shall approximate the general nature of the premining
topography. The requirements of this section may be modified in the permit and
plan where the surface mining activities are reaffecting previously mined lands
that have not been restored to the standards of this chapter and sufficient
spoil is not available to otherwise comply with this section. The person who
conducts surface mining activities, at a minimum, shall-
1. Retain all overburden and spoil on the
solid portion of existing or new benches; and
2. Backfill and grade to the most moderate
slope possible, to eliminate the highwall which does not exceed either the
angle of repose or a lesser slope as is necessary to achieve a minimum static
safety factor of one and three-tenths (1.3). In all cases the highwall shall be
eliminated.
(B) On
approval in the permit and plan 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 post-mining land
use and are appropriate substitutes for construction of lower grades on the
reclaimed lands. The terraces shall meet the following requirements:
1. The slope of the individual terrace bench
shall not exceed twenty feet (20') unless specifically approved in the permit
and plan as necessary for stability, erosion control or roads included in the
approved post-mining land use plan;
2. The vertical distance between terraces
shall be as specified in the permit and plan, to prevent excessive erosion and
to provide long-term stability;
3.
The slope of the terrace outslope shall not exceed 1v:2h (50%). Outslopes which
exceed 1v:2h (50%) may be approved, if they have a minimum static safety factor
of more than one and three-tenths (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; and
4. Culverts and underground rock drains shall
be used on the terrace only when approved in the permit and plan.
(C) Small depressions may be
constructed, if they-
1. Are approved in the
permit and plan to minimize erosion, conserve soil moisture or promote
vegetation;
2. Do not restrict
normal access; and
3. Are not
inappropriate substitutes for lower grades on the reclaimed lands.
(D) All surface mining activities
on slopes above twenty degrees (20°) or on lesser slopes that the permit
and plan defines as steep slopes shall meet the provisions of
10 CSR
40-4.040.
(E) All final grading, preparation of
overburden before replacement of topsoil and placement of topsoil shall be done
along the contour to minimize subsequent erosion and instability. If this
grading, preparation, or placement along the contour is unnecessary or is
hazardous to equipment operations, then grading, preparation or placement in a
direction other than generally parallel to the contour may be used if approved
in the permit and plan. In all cases, grading, preparation or placement shall
be conducted in a manner which minimizes erosion and provides a surface for
replacement of topsoil which will minimize slippage.
(3) Covering Coal Seams, Combustible and
Acid-Forming and Toxic-Forming Materials.
(A)
Cover.
1. Exposed coal seams, acid-forming
and toxic-forming materials and combustible materials exposed, used or produced
during mining shall be adequately covered with nontoxic and noncombustible
material or treated, to control the impact on surface and ground water in
accordance with 10 CSR 40-3.040, to prevent
sustained combustion and to minimize adverse effects on plant growth and the
approved post-mining land use. Coal processing waste and noncoal waste shall be
covered in accordance with
10 CSR
40-3.080.
2. Where necessary to protect against upward
migration of salts, exposure to erosion, formation of acid or toxic seeps, to
provide an adequate depth for plant growth or otherwise to meet local
conditions, the permit and plan shall specify thicker amounts of cover using
nontoxic material, or special compaction and isolation from groundwater
contact.
3. Acid-forming or
toxic-forming material, combustible materials and coal processing waste shall
not be buried or stored in proximity to a drainage course so as to cause or
pose a threat of water pollution.
(B) Stabilization. Backfilled materials shall
be selectively hauled or conveyed and compacted, wherever necessary, to prevent
leaching of acid- and toxic-forming materials into surface or ground waters and
wherever necessary to ensure stability of the backfilled materials. The method
and design specifications of compacting material shall be approved in the
permit and plan before acid-or toxic-forming materials are covered.
(4) Thin Overburden.
(A) The provisions of this section apply only
where there is insufficient spoil and other waste materials available from the
entire permit area to restore the disturbed area to its approximate original
contour. Insufficient spoil and other waste materials occur where the
overburden thickness times the swell factor, plus the thickness of other
available waste materials, is less than the combined thickness of the
overburden and coal bed prior to removing the coal, so that after backfilling
and grading the surface configuration of the reclaimed area would not:
1. Closely resemble the surface configuration
of the land prior to mining; or
2.
Blend into and complement the drainage pattern of the surrounding terrain. The
provisions of this section apply only when surface mining activities cannot be
carried out to comply with section (1) of this rule to achieve the approximate
original contour.
(B) 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 mine
plan 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:
1. Haul or convey, 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 one and three-tenths (1.3), and to provide adequate drainage and long-term
stability of the regraded areas and cover all acid- and toxic-forming
materials;
2. Eliminate highwalls
by grading or backfilling to stable slopes not exceeding 1v:2h (50%) or lesser
slopes as may be specified in the permit and plan to reduce erosion, maintain
the hydrologic balance or allow the approved post-mining land use;
3. Haul or convey, backfill, grade and
revegetate, in accordance with 10 CSR 403.120(1)-(7), to achieve an
ecologically sound land use compatible with the prevailing use in unmined areas
surrounding the mine plan area; and
4. Haul or convey, backfill and grade, to
ensure impoundments are constructed only where-
A. It has been demonstrated that all
requirements of 10 CSR
40-3.040(1)-(16) have been met;
and
B. The impoundments have been
approved in the permit and plan as suitable for the approved post-mining land
use as meeting the requirements of this chapter and all other applicable
federal and state laws and regulations.
(5) Thick Overburden.
(A) The provisions of this section apply only
where there is more than sufficient spoil and other waste materials available
from the entire permit area to restore the disturbed area to its approximate
original contour. More than sufficient spoil and other waste materials occur
where the overburden thickness times the swell factor exceeds the combined
thickness of the overburden and coal bed prior to removing the coal, so that
after backfilling and grading the surface configuration of the reclaimed area
would not:
1. Closely resemble the surface
configuration of the land prior to mining; or
2. Blend into and complement the drainage
pattern of the surrounding terrain. The provisions of this section apply only
when surface mining activities cannot be carried out to comply with section (1)
of this rule to achieve the approximate original contour.
(B) In surface mining activities where the
volume of spoil over the mine plan 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:
1. Haul or convey, backfill and grade all
spoil and wastes not required to achieve the approximate original contour of
the mine plan area, to the lowest practicable grade, to achieve the static
factor of safety of one and three-tenths (1.3) and cover all acid-forming and
other toxic-forming materials;
2.
Haul or convey, backfill and grade excess spoil and wastes only within the
permit area and dispose of those materials in accordance with
10 CSR
40-3.060(1)-(4);
3. Haul or convey, backfill and grade excess
spoil and wastes to maintain the hydrologic balance, in accordance with
sections 10
CSR 40-3.040(1)-(17), and to provide
long-term stability by preventing slides, erosion and water
pollution;
4. Haul or convey,
backfill, grade and revegetate wastes and excess spoil to achieve an
ecologically sound land use approved in the permit and plan as compatible with
the prevailing land uses in unmined areas surrounding the mine plan
area;
5. Eliminate all highwalls
and depressions by backfilling with spoil and suitable waste materials;
and
6. Meet the revegetation
requirements of 10 CSR
40-3.120(1)-(7) for all disturbed
areas.
(6)
Regrading or Stabilizing Rills and Gullies.
(A) When rills or gullies deeper than nine
inches (9") form in areas that have been regraded and topsoiled, the rills and
gullies shall be stabilized as soon as weather and soil conditions permit by
use of temporary or permanent measures. Rills and gullies deeper than nine
inches (9") which have formed prior to August 1 of any year and which either 1)
disrupt the approved post-mining land use or the reestablishment of the
vegetative cover, or 2) cause or contribute to a violation of water quality
standards for receiving streams shall be filled, graded and topsoiled by
September 1 of each year and reseeded or replanted according to
10 CSR
40-3.120(1)- (7) as soon as weather
and soil conditions permit, but no later than September 30 of each year. Rills
and gullies of lesser depth which have formed prior to August 1 of any year
must be permanently or temporarily stabilized as soon as weather and soil
conditions permit and permanently repaired and topsoiled, if in a topsoiled
area, by September 30 of each year if the rills and gullies disrupt the
approved land use or the reestablishment of a vegetative cover or cause or
contribute to a violation of water quality standards for receiving
stream.
(B) On areas that have been
previously mined, the requirements for regrading or stabilizing rills and
gullies pursuant to subsection (6)(A) apply after final grading and placement
of topsoil or the best available topsoil substitute.
Notes
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