30 CFR 817.71 - How must I dispose of excess spoil?
(a)General requirements. You, the permittee or operator, must mechanically transport and place excess spoil in designated disposal areas, including approved valley fills and other types of approved fills, within the permit area in a controlled manner in compliance with the requirements of this section. In general, you must place excess spoil in a manner that will -
(2) Ensure mass stability and prevent mass movement during and after construction.
(3) Ensure that the final surface configuration of the fill is suitable for revegetation and the approved postmining land use or uses and is compatible with the natural drainage pattern and surroundings.
(4) Minimize disturbances to, and adverse impacts on, fish, wildlife, and related environmental values to the extent possible, using the best technology currently available.
(5) Ensure that the fill will not change the size or frequency of peak flows from precipitation events or thaws in a way that would result in an increase in flooding when compared with the impacts of premining peak flows.
(7) Ensure that the fill will not cause or contribute to a violation of applicable state or tribal water quality standards for surface water located downstream of the toe of the fill, including, but not limited to, water quality standards established under the authority of section 303(c) of the Clean Water Act, 33 U.S.C. 1313(c).
(b)Stability requirements. -
(1)Static safety factor. You must design and construct the fill to attain a minimum long-term static safety factor of 1.5. The foundation and abutments of the fill must be stable under all conditions of construction.
(2)Special requirement for steep-slope conditions. Where the slope in the disposal area exceeds 2.8h:1v (36 percent), or any lesser slope designated by the regulatory authority based on local conditions, you must construct bench cuts (excavations into stable bedrock) or rock-toe buttresses to ensure fill stability.
(d)Requirements for handling of organic matter and soil materials. You must remove all vegetation, other organic matter, and soil materials from the disposal area prior to placement of the excess spoil. You must store, redistribute, or otherwise use those materials in accordance with § 817.22 of this part. You may use soil substitutes and supplements if approved in the permit in accordance with § 784.12(e) of this chapter.
(e)Surface runoff control requirements.
(i) Meet the requirements of § 817.43 of this part; and
(ii) Safely pass the runoff from a 100-year, 6-hour precipitation event. You must use the appropriate regional Natural Resources Conservation Service synthetic storm distribution to determine the peak flow from surface runoff from this event.
(2) You must grade the top surface of a completed fill such that the final slope after settlement will be toward properly designed drainage channels. You may not direct uncontrolled surface runoff over the outslope of the fill.
(f)Control of water within the footprint of the fill. -
(1)General requirements. If the disposal area contains springs, natural or manmade water courses, or wet weather seeps, you must design and construct underdrains and temporary diversions as necessary to control erosion, prevent water infiltration into the fill, and ensure stability.
(i) You must construct underdrains that are comprised of hard rock that is resistant to weathering.
(ii) You must design and construct underdrains using current, prudent engineering practices and any design criteria established by the regulatory authority.
(iii) In constructing rock underdrains, you may use only hard rock that is resistant to weathering, such as well-cemented sandstone and massive limestone, and that is not acid-forming or toxic-forming. The underdrain must be free of soil and fine-grained, clastic rocks such as siltstone, shale, mudstone, and claystone. All rock used to construct underdrains must meet the criteria in the following table:
|Test||ASTM standard||AASHTO standard||Acceptable results|
|Los Angeles Abrasion||C 131 or C 535||T 96||Loss of no more than 50 percent of test sample by weight.|
|Sulfate Soundness||C 88 or C 5240||T 104||Sodium sulfate test: Loss of no more than 12 percent of test sample by weight.
Magnesium sulfate test: Loss of no more than 18 percent of test sample by weight.
(iv) The underdrain system must be designed and constructed to carry the maximum anticipated infiltration of water due to precipitation, snowmelt, and water from seeps and springs in the foundation of the disposal area away from the excess spoil fill.
(v) To provide a safety factor against future changes in local surface-water and groundwater hydrology, perforated pipe may be embedded within the rock underdrain to enhance the underdrain capacity to carry water in excess of the anticipated maximum infiltration away from the excess spoil fill. The pipe must be manufactured of materials that are not susceptible to corrosion and must be demonstrated to be suitable for the deep burial conditions commonly associated with excess spoil fill underdrains.
(vi) The underdrain system must be protected from material piping, clogging, and contamination by an adequate filter system designed and constructed using current, prudent engineering practices to ensure the long-term functioning of the underdrain system.
(g)Placement of excess spoil.
(1) Using mechanized equipment, you must transport and place excess spoil in a controlled manner in horizontal lifts not exceeding 4 feet in thickness; concurrently compacted as necessary to ensure mass stability and to prevent mass movement during and after construction; and graded so that surface and subsurface drainage is compatible with the natural surroundings.
(3)Acid-forming, toxic-forming, and combustible materials.
(i) You must handle acid-forming and toxic-forming materials in accordance with § 817.38 of this part and in a manner that will minimize adverse effects on plant growth and the approved postmining land use.
(ii) You must cover combustible materials with non combustible materials in a manner that will prevent sustained combustion and minimize adverse effects on plant growth and the approved postmining land use.
(1) The final configuration of the fill must be suitable for the approved postmining land use, compatible with the natural drainage pattern and the surrounding terrain, and, to the extent practicable, consistent with natural landforms.
(2) You may construct terraces on the outslope of the fill if required for stability, to control erosion, to conserve soil moisture, or to facilitate the approved postmining land use. The grade of the outslope between terrace benches may not be steeper than 2h: 1v (50 percent).
(i) You must configure the top surface of the fill to create a topography that includes ridgelines and valleys with varied hillslope configurations when practicable, compatible with stability and postmining land use considerations, and generally consistent with the topography that existed before any mining.
(ii) The final surface elevation of the fill may exceed the elevation of the surrounding terrain when necessary to minimize placement of excess spoil in perennial and intermittent streams, provided the final configuration complies with the requirements of paragraphs (a)(3) and (h)(1) of this section.
(iii) The geomorphic reclamation requirements of paragraph (h)(3)(i) of this section do not apply in situations in which they would result in burial of a greater length of perennial or intermittent streams than traditional fill design and construction techniques.
(1) Are needed to retain moisture, minimize erosion, create or enhance wildlife habitat, or assist revegetation;
(2) Are not incompatible with the stability of the fill;
(5) Are approved by the regulatory authority.
(j)Surface area stabilization. You must provide slope protection to minimize surface erosion at the site. You must revegetate all disturbed areas, including diversion channels that are not riprapped or otherwise protected, upon completion of construction.
(k)Inspections and examinations.
(1) A qualified registered professional engineer, or other qualified professional specialist under the direction of the professional engineer, must inspect the fill at least quarterly during construction, with additional complete inspections conducted during critical construction periods. The professional engineer or specialist must be experienced in the construction of earth and rock fills. Critical construction periods include, at a minimum -
(i) Foundation preparation, including the removal of all organic matter and soil materials.
(ii) Placement of underdrains and protective filter systems.
(iii) Installation of final surface drainage systems.
(2) An engineer or specialist meeting the qualifications of paragraph (k)(1) of this section also must -
(i) Conduct daily examinations during placement and compaction of fill materials or, when more than one lift is completed per day, upon completion of each 4-foot lift. As an alternative, the engineer or specialist may conduct examinations on a weekly basis if a mine representative takes photographs on a daily basis to document the lift thickness and elevation with visual reference features. The certified report required by paragraph (k)(3) of this section must include this photographic documentation.
(ii) Maintain a log recording the examinations conducted under paragraph (k)(2)(i) of this section for each 4-foot lift in each fill. The log must include a description of the specific work locations, excess spoil placement methods, compaction adequacy, lift thickness, suitability of fill material, special handling of acid-forming and toxic-forming materials, deviations from the approved permit, and remedial measures taken.
(ii) In each report prepared under paragraph (k)(3)(i) of this section, the engineer must certify that the fill has been constructed and maintained as designed and in accordance with the approved plan and this chapter.
(iii) The report prepared under paragraph (k)(3)(i) of this section must identify and discuss any evidence of instability, structural weakness, or other hazardous conditions. If one of more of those conditions exists, you must submit an application for a permit revision that includes appropriate remedial design specifications.
(iv) The report prepared under paragraph (k)(3)(i) of this section must contain -
(A) A review and summary of all complete inspections conducted during the quarter under paragraph (k)(1) of this section.
(C) The photographs taken under paragraph (k)(2)(i) of this section.
(iv) Each certified report prepared under paragraph (k)(3) of this section for a quarter in which construction activities include placement of underdrains and protective filter systems must 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 must be certified separately. The photographs 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.
(4) You must retain a copy of each certified report prepared under paragraph (k)(3) of this section at or near the mine site.
(i) Cause or contribute to a violation of applicable state or tribal water quality standards or effluent limitations, including, but not limited to, water quality standards established under the authority of section 303(c) of the Clean Water Act, 33 U.S.C. 1313(c), and effluent limitations established in any National Pollutant Discharge Elimination System permit issued for the operation under section 402 of the Clean Water Act, 33 U.S.C. 1342, or its state or tribal counterpart;
(iii) Result in material damage to the hydrologic balance outside the permit area.
(3) The waste is nontoxic-forming, nonacid-forming, and non-combustible.
(4) The waste is of the proper characteristics to be consistent with the design stability of the fill.
(m)Underground disposal. You may dispose of excess spoil in underground mine workings only in accordance with a plan approved by the regulatory authority and the Mine Safety and Health Administration under § 784.26 of this chapter.
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- 30 CFR 942.817 — Performance Standards - Underground Mining Activities.
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