N.D. Admin Code 69-05.2-18-01 - Performance standards - Disposal of excess spoil - Requirements
In addition to satisfying subsection 19 of North Dakota Century Code section 38-14.1-24, the operator shall:
1. Place excess spoil from the
initial pit and excess spoil not needed to meet the grading requirements of
section 69-05.2-21-02 in approved
designated disposal areas within a permit area. The spoil must be placed in a
controlled manner to ensure:
a. That leachate
and surface runoff from the disposal area will not degrade surface or ground
waters or exceed effluent limitations.
b. Stability of the disposal area.
c. That the land mass designated as the
disposal area is suitable for reclamation and revegetation compatible with the
natural surroundings.
2.
Design the fill and appurtenant structures using current, prudent engineering
practices and meet any design criteria established by the commission. A
qualified registered professional engineer experienced in the design of earth
and rock fills shall certify the design of the fill and appurtenant
structure.
3. Clear all vegetative
and organic materials from the disposal area and handle suitable plant growth
material according to 69-05.2-15. If approved by the commission, organic
material may be used as mulch or included in the suitable plant growth material
to control erosion, promote growth of vegetation, or increase soil moisture
retention.
4. Divert surface water
runoff from the area above the disposal area into stabilized diversion channels
designed to meet the requirements of sections
69-05.2-16-06 and
69-05.2-16-07.
5. Transport and place excess spoil in a
controlled manner in horizontal lifts not exceeding four feet [1.22 meters]
thick; concurrently compact to ensure mass stability and prevent mass movement
during and after construction; grade so that surface and subsurface drainage is
compatible with natural surroundings; and cover with suitable plant growth
material. The commission may approve a design which employs other than
four-foot [1.22-meter] lifts of excess spoil if it is demonstrated by the
operator and certified by a qualified registered professional engineer that the
design will ensure stability of the fill and meet all other applicable
requirements.
6. Provide slope
protection to minimize surface erosion at the site. Diversion design must meet
the requirements of section
69-05.2-16-06. All disturbed
areas, including diversion ditches that are not riprapped, must be vegetated
upon completion of construction.
7.
Not direct drainage over the outslope of the disposal area without commission
approval.
8. Locate the disposal
area on the most naturally stable area available as approved by the commission.
Where possible, fill materials suitable for disposal must be placed upon or
above a natural terrace, bench, or berm if the placement provides additional
stability.
9. Construct the
disposal area to ensure a long-term static safety factor of 1.5.
10. Not allow depressions or impoundments on
the completed disposal area.
11.
Utilize terraces to control erosion and enhance stability if approved by the
commission and consistent with section
69-05.2-21-02.
12. Inspect the disposal area as follows:
a. Each disposal area must be inspected for
stability by a registered professional engineer at least quarterly throughout
construction and during critical construction periods. Critical construction
periods include: foundation preparation including removal of all organic
material and suitable plant growth material, placement of underdrainage
systems, installation of surface drainage systems, placement and compaction of
fill materials, and the final graded and revegetated fill. The registered
professional engineer shall provide a certified report to the commission within
two weeks after each inspection that the disposal area has been constructed as
specified in the design approved by the commission. The report must include
appearances of instability, structural weakness, and other hazardous
conditions.
b. The certified report
on the drainage system and protective filters must include color photographs
taken during and after construction but before the underdrains are covered with
excess spoil. If the underdrain system is constructed in phases, each phase
must be certified separately.
c.
Where excess durable rock spoil is placed in single or multiple lifts such that
the underdrain system is constructed simultaneously with the excess spoil
placement by the natural segregation of dumped materials, color photographs
must be taken of the underdrain as the underdrain system is being
formed.
d. The photographs
accompanying each certified report must 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.
e. A copy of the report must
be retained at the minesite.
13. Provide an underdrain system, if required
by subsection 19 of North Dakota Century Code section
38-14.1-24, that is protected by
an adequate filter and designed and constructed using standard geotechnical
engineering methods. Underdrains must consist of nondegradable,
non-toxic-forming rock such as natural sand and gravel, sandstone, limestone,
or other durable rock that will not slake in water and will be free of coal,
commercial leonardite, clay, or shale.
14. Ensure the foundation and abutments of
the disposal area are stable under all conditions of construction and
operation. Sufficient foundation investigation and laboratory testing must be
performed to determine the design requirements for stability of the foundation.
Where the slope of the disposal area exceeds 1v:5h (twenty percent), the
existing ground must be plowed, stepped, or keyed in a manner which increases
the stability of the disposal area.
15. Construct the outslope of the disposal
area to not exceed 1v:2h (fifty percent) or a lesser slope required by the
commission.
Notes
General Authority: NDCC 38-14.1-03
Law Implemented: NDCC 38-14.1-24
State regulations are updated quarterly; we currently have two versions available. Below is a comparison between our most recent version and the prior quarterly release. More comparison features will be added as we have more versions to compare.
No prior version found.