Current through Register Vol. XLI, No. 50, December 13, 2024
Section 38-3-9 - Permanent Excess Spoil Disposal, Temporary Spoil Storage Areas9.1. Disposal of Excess Spoil in Side of Hill Fills. -- Excess spoil or material to be placed in permanent disposal sites shall be transported to and placed in a controlled manner in disposal areas other than the mine workings or excavation only if all the provisions of this section are met.9.1.a. Location of Disposal Sites. - Permanent excess spoil disposal areas shall be identified on the proposal map, shall be located within the permit area, and they must be approved by the Secretary as suitable for construction of fills. The disposal area shall be located on the most moderate slopes and naturally stable areas available.9.1.b. Certification. -- Certification of the fill shall be as follows: 9.1.b.1. The fill shall be designed using recognized professional standards and certified by an approved registered professional engineer; and9.1.b.2. The fill shall be inspected for stability by an approved registered professional engineer after completion of the first fifty-foot (50') lift, to assure the following requirements are met: 9.1.b.2.A. Removal of all organic material and topsoil;9.1.b.2.B. Placement of under-drainage systems; and9.1.b.2.C. Proper construction in accordance with the approved permit.9.1.b.3 The approved registered professional engineer shall also provide a certified report upon completion of the fill that the fill has been constructed as designed in the approved permit.9.1.b.4. Any deviations from the approved permit which result from unforeseen site specific circumstances arising during construction, shall be reflected in as-built plans submitted by the operator and approved by the Secretary immediately following construction. The as-built plans shall include the following:9.1.b.4.A. The original design;9.1.b.4.B. The extent of the changes; and9.1.b.4.C. The reference points. 9.1.b.4.C.1. If as built plans are submitted, the certification shall:9.1.b.4.C.1.(a) Describe how and to what extent the construction deviates from the proposed design; and9.1.b.4.C.1.(b) Certify that the fill will meet all the requirements of this rule.9.1.c. Stabilization. -- Where the slope in the disposal area exceeds 2.8 horizontal to one (1) vertical (thirty-six (36%) percent), or where necessary to achieve a static safety factor of 1.5, measures such as keyway cuts, rock toe buttresses or other techniques shall be used. All organic material shall be removed from the disposal area and the topsoil must be removed and segregated before the overburden is placed in the disposal area. Suitable organic material may be used as mulch or may be included in the topsoil. The spoil shall be transported and placed in a controlled manner, concurrently compacted as necessary to ensure long-term mass stability and prevent mass movement. The fill shall be drained and graded to allow surface and subsurface drainage to be compatible with the natural surroundings.9.1.d. Drainage. -- The disposal area shall not contain springs, natural water courses or wet weather seeps unless lateral drains are constructed from the wet areas to the under drains in such a manner that infiltration of the water into the fill shall be prevented. The drains shall be designed and constructed of course rock. If no filter is designed for the under drain, sufficient capacity shall be provided to allow for partial plugging of the drain. No rock shall be used in under drains if it tends to disintegrate or if it is acid-forming or toxic-forming.9.1.e. Construction. -- Construction of the fill shall be as follows:9.1.e.1. All areas upon which the fill is to be placed shall first be progressively cleared of all trees, brush, and shrubs. This material shall be removed from the fill area;9.1.e.2. Depositing and compacting the fill in layers shall begin at the toe of the fill. The layers shall be constructed approximately parallel with proposed finish grade. All material shall be deposited in uniform horizontal layers and compacted with haulage equipment;9.1.e.3. The thickness of the layers shall not exceed four (4) feet;9.1.e.4. The outer slope or face of the fill shall be regraded to be no steeper than two (2) horizontal to one (1) vertical (2:1) Provided, That constructed fill slopes may be steeper if they meet a static safety factor of one point five (1.5) and are certified by a registered professional engineer. Benches shall be constructed on the fill at a maximum of every fifty feet (50') in vertical rise above the toe of the fill. The benches shall be no less than twenty feet (20') in width and slope toward the fill at a three (3) to five (5) percent grade and slope laterally at one (1) percent grade to discharge channels capable of passing the peak runoff for a one-hundred (100) year twenty-four (24) hour precipitation event; and9.1.e.5. When construction of each lift (maximum of every fifty feet (50') in vertical height) of the fill is completed, topsoil or other suitable material which will support vegetation shall be spread over the completed slope and bench. The slopes and benches shall then be seeded and mulched immediately in accordance with the approved revegetation plans.9.2. Disposal of Excess Spoil Material in Valley Fills. -- Excess spoil or material to be placed in permanent overburden disposal sites shall be transported to and placed in a controlled manner; spoil to be disposed of in natural valleys must be placed in accordance with the following requirements:9.2.a. Location of Excess Spoil Areas. - Permanent excess spoil disposal areas shall be identified on the proposal map, shall be within the permit area and they must be approved by the Secretary as suitable for construction of fills. The disposal area shall be located on the most moderate slopes and naturally stable areas available.9.2.b. Certification. -- Certification of the fill shall be as follows: 9.2.b.1. The fill shall be designed using recognized professional standards and certified by an approved registered professional engineer; and9.2.b.2. The fill shall be inspected for stability by an approved registered professional engineer after completion of the first fifty foot (50') lift to assure the following requirements are met: 9.2.b.2.A. Removal of all organic material and topsoil;9.2.b.2.B. Placement of under-drainage systems; and9.2.b.2.C. Proper construction is in accordance with the approved permit.9.2.b.3. The approved registered professional engineer shall also provide a certified report upon completion of the fill that the fill, has been constructed as designed in the approved permit.9.2.b.4. Any deviations from the approved permit which result from unforeseen site specific circumstances arising during construction, shall be reflected in as-built plans submitted by the operator and approved by the Secretary immediately following construction. The as-built plans shall include the following:9.2.b.4.A. The original design;9.2.b.4.B. The extent of the changes; and9.2.b.4.C. The reference points. 9.2.b.4.C.1. If as built plans are submitted, the certification shall:9.2.b.4.C.1.(a) Describe how and to what extent the construction deviates from the proposed design; and9.2.b.4.C.1.(b) Certify that the fill will meet all the requirements of this rule.9.2.c. Stabilization. -- Where the slope in the disposal area exceeds 2.8 horizontal to one (1) vertical (thirty-six percent (36%)) or where necessary to achieve a static safety factor of 1.5, measures such as keyway cuts, rock toe buttresses or other techniques shall be used. All organic material shall be removed from the disposal area and the topsoil must be removed and segregated before the overburden is placed in the disposal area. Suitable organic material may be used as mulch or may be included in the topsoil. The spoil shall be transported and placed in a controlled manner, concurrently compacted as necessary to insure long-term mass stability and prevent mass movement. The fill shall be drained and graded to allow surface and subsurface drainage to be compatible with the natural surroundings.9.2.d. Drainage. -- The disposal area shall not contain springs, natural water courses or wet weather seeps unless lateral drains are constructed from the wet areas to the under drains in such a manner that infiltration of the water into the fill shall be prevented. If springs, natural watercourses or wet weather seeps are encountered, a system of under drains shall be constructed from each spring or seepage area as lateral drains to the rock core. If no filter is designed for the under drain, sufficient capacity shall be provided to allow for partial plugging of the drain. No rock shall be used in under drains if it tends to disintegrate or if it is acid-forming or toxic-forming.9.2.e. Construction. -- Construction of the fill shall be as follows:9.2.e.1. All areas upon which the fill is to be placed shall first be progressively cleared of all trees, brush, and shrubs. This material shall be removed from the fill area. No more than three (3.0) acres, excluding roadway for construction of fill, shall be cleared in the valley fill site until the first lift is completed;9.2.e.2. A rock core shall be progressively constructed as the layers are brought up through the valley fill. The rock core shall be a minimum of sixteen feet (16') in width and composed of rock with a minimum dimension of twelve inches (12"). The rock core shall consist of no more than ten percent (10%) fines as determined by visual inspection (fines being a material with a dimension of less than twelve inches) (12");9.2.e.3. Depositing and compacting the fill in layers shall begin at the toe of the fill. The layers shall be constructed approximately parallel with proposed finish grade. All material shall be deposited in uniform horizontal layers and compacted with haulage equipment;9.2.e.4. The thickness of the layers shall not exceed four feet (4');9.2.e.5. During and after construction, the top of the fill shall be graded to drain back to the head of the fill on a slope no greater than three percent (3%). A drainage pocket shall be maintained at the head of the fill at all times to intercept surface runoff. Maximum size of the drainage pocket shall be ten thousand (10,000) cubic feet;9.2.e.6. The outer slope or face of the fill shall be regraded to be no steeper than two (2) horizontal to one (1) vertical (2:1) Provided, That constructed fill slopes may be steeper if they meet a static safety factor of one point five (1.5) and are certified by a registered professional engineer. Benches shall be constructed on the fill at a maximum of every fifty feet (50') in vertical rise above the toe of the fill. The benches shall be no less than twenty feet (20') in width and slope toward the fill at a three (3) to five (5) percent grade and slope laterally at one (1) percent grade to discharge channels capable of passing the peak runoff for a one-hundred (100) year twenty-four (24) hour precipitation event.9.2.e.7. When construction of each lift (maximum of every fifty feet (50') in vertical height) of the valley fill is completed, topsoil or other suitable material which will support vegetation shall be spread over the completed slope and bench excluding the rock core. The completed slope and bench shall then be seeded and mulched immediately in accordance with the approved revegetation plans.9.3. Disposal of Excess Spoil Material in Durable Rock Fills. -- The Secretary may approve the design, construction, and use of a single lift fill consisting of at least eighty percent (80%) durable rock if it can be determined, based on information provided by the operator, that the following conditions exist: 9.3.a. Permanent excess disposal areas shall be identified on the proposal map, be within the permit area, and they must be approved by the Secretary as suitable for construction of fills. The disposal area shall be located on the most moderate slopes and naturally stable areas available.9.3.b. Geotechnical Information. -- Examination of core borings and the geologic column show that the overburden consists of durable sandstone, limestone, or other durable material in sufficient thickness and amounts to generate spoil material that is eighty percent (80%) or greater durable rock. Where the fill will contain non-cemented clay shale, clay spoil, or other nondurable material, such material must be mixed with durable rock in a controlled manner such than no more than twenty percent (20%) of the fill volume is not durable rock. Tests shall be performed by a qualified laboratory, and approved by the Secretary to demonstrate that no more than twenty percent (20%) of the fill is not durable rock. 9.3.b.1. The durable rock shall not consist of acid-producing or toxic-forming material, will not slake in water, or will not degrade to soil material. For purposes of this paragraph only, soil material means material of which at least fifty percent (50%) is finer than 0.074 mm, which exhibits plasticity, and which meets the criteria for group symbol ML, CL, OL, MH, CH, or OH, as determined by the United Soil Classification System (ASTM D-2487).9.3.b.2. The toe of the fill shall rest on natural slopes no steeper than twenty percent (20%).9.3.c. The fill shall be designed based on the results of sufficient geotechnical investigations of the construction site. The investigation shall include such factors as geologic conditions, soil characteristics, depth to bedrock location of springs, seeps and groundwater flow, potential effects of subsidence and a description of materials to be placed in rock cores and drains.9.3.d. The design and construction of all durable rock fills must be certified by a registered professional engineer experienced in design and construction of earth and rock embankments.9.3.e. The foundation of the fill and the fill shall be designed to assure a long-term static safety factor of 1.5 or greater, and meet an earthquake safety factor of 1.1.9.3.f. All areas upon which the fill is to be placed shall first be progressively cleared of all trees, brush, and shrubs which are above ground level; provided; that in critical foundation areas, including, but not limited to, the toe of the fill, seepage or underdrain areas, and downstream portions of the fill that provide resisting force against massive slope failure, all organic material both above and below that ground surface must be removed. This material shall be disposed of outside the fill area.9.3.g. The underdrain system may be constructed simultaneously with excess spoil placement by natural segregation of dumped materials; provided, that the resulting underdrain system shall be capable of carrying anticipated seepage of water due to rainfall away from the excess spoil fill, and from seeps and other springs in the foundation of the disposal area, and the other requirements for drainage control shall be met. If the underdrain system is not constructed by natural segregation of dumped material, it shall be designed and constructed in accordance with subdivision 9.1.d. of this rule.9.3.h. Surface water runoff from areas above and adjacent to the fill shall be diverted into properly designed and constructed stabilized diversion channels which have been designed using the best current technology to safely pass the peak runoff from a one hundred (100) year, twenty four (24) hour precipitation event. The channel shall be designed and constructed to ensure stability of the fill, control erosion, and minimize water infiltration into the fill.9.3.i. The grade of the top surface of the completed fill shall not exceed five percent (5%) and shall slope toward the drainage channel.9.3.j. The outer slope or face of the fill shall be regraded to be no steeper than two (2) horizontal to one (1) vertical (2:1) Provided, That constructed fill slopes may be steeper if they meet a static safety factor of one point five (1.5) and are certified by a registered professional engineer. Benches shall be constructed on the fill at a maximum of every fifty feet (50') in vertical rise above the toe of the fill. The benches shall be no less than twenty feet (20') in width and slope toward the fill at a three (3) to five (5) percent grade and slope laterally at one (1) percent grade to discharge channels capable of passing the peak runoff for a one-hundred (100) year twenty-four (24) hour precipitation event.9.3.k. No permanent impoundments may be constructed on the completed fill except small depressions may be allowed if they are needed to retain moisture, minimize erosion, create and enhance wildlife habitat, or assist revegetation; and if they are not incompatible with the stability of the fill.9.3.l. Notwithstanding any other provisions of this rule or terms and conditions of a permit to the contrary, additional storage capacity or sediment control measures may be required through permit revision if sediment removal performance of the structure(s) during operation and construction of the fill is found to be deficient to the point that significant non-compliance with applicable effluent limits or water quality standards results.9.3.m. The following materials are hereby prohibited from being placed, deposited, or disposed of into a durable rock fill or durable rock fill area: 9.3.m.1. Surface soils, provided that such soils used to establish vegetation on the surface of the fill are not prohibited; provided, however, such soils may be placed in the fill if accounted for in design and construction as nondurable material, and such soils are not deposited in critical zones of the fill;9.3.m.2. Mud, silt, or sediment cleaned or removed from mining pits, roadways, sediment control structures and/or other areas of the operation;9.3.m.3. Vegetative or organic materials cleared or grubbed from the permit or other areas; and9.3.n. Inspection and Certification of Durable Rock Fills. -- Certification of all durable rock fills shall be required as follows: 9.3.n.1. The fill and appurtenant structures shall be designed in accordance with professional design standards, which meet the requirements of this subsection, and certified by a registered professional engineer experienced in the design of earth and rock fill embankments;9.3.n.2. During construction, the fill shall be inspected quarterly for stability by a registered professional engineer experienced in the construction of earth or rock fills or other qualified professional specialist working under the direction of a professional engineer experienced in the construction of earth or rock fills. Regular inspections are also required during placement and compaction of fill materials and during critical construction periods such as foundation preparation, underdrain placement, installation of surface drainage systems, and construction of rock toe buttresses. Within two (2) weeks following completion of the inspections, a report certified by the registered professional engineer shall be submitted to the Secretary. The certified report shall contain a statement that the fill is being constructed and maintained as designed in accordance with the approved plan and this rule. The report shall also note any instances of apparent instability, structural weaknesses, and other hazards. The report on the drainage system and protective filters shall include color photographs taken during and after construction, but before the underdrains are covered with excess spoil. Color photographs shall be of sufficient size and number to provide a relative scale and to clearly identify the site. If the underdrains are constructed in phases, each phase must be certified separately. If excess durable rock spoil is placed such that the underdrain system is constructed simultaneously with excess spoil placement by the natural segregation of dumped materials, color photographs of the underdrains must be taken as they are formed. All color photographs shall be of adequate size and number to provide a relative scale and to clearly identify the site. A copy of the certified report shall be maintained at the mine site;9.3.n.3. After total completion of the fill, a certification form shall be completed and submitted to the Secretary by the registered professional engineer overseeing construction of the fill; and9.3.n.4. In addition to the requirements of subparagraph (2) of this paragraph, certification forms for durable rock fills shall be accompanied by the following: 9.3.n.4.A. A statement attesting that the fill contains no more than twenty percent (20%) non-durable material;9.3.n.4.B. A statement attesting that foundation preparation is proceeding in accordance with the design plans;9.3.n.4.C. A statement that prohibited materials are not being placed, deposited, or disposed of into the fill area; and9.3.n.4.D. A statement that sediment control measures are constructed and being maintained in accordance with the approved design plans, and the terms and conditions of the permit.9.3.n.4.E. Any deviations from the approved drainage plan which result from unforeseen site specific circumstances arising during construction, shall be reflected in as-built plans submitted by the operator and approved by the Secretary immediately following construction. The as-built plans shall include the following:9.3.n.4.E.1. The original design;9.3.n.4.E.2. The extent of the changes; and9.3.n.4.E.3. The reference points.9.3.n.4.F. If as built plans are submitted, the certification shall:9.3.n.4.F.1. Describe how and to what extent the construction deviates from the proposed design; and9.3.n.4.F.2. Certify that the fill will meet all the requirements of this rule.9.4. Disposal of Excess Spoil Material in Spoil Piles. -- Excess spoil being placed in permanent overburden disposal sites on natural ground with an original slope of less than twenty (20) degrees shall be transported to and placed in a controlled manner; spoil piles must be placed in accordance with the following requirements:9.4.a. Location of Disposal Sites. - Permanent excess disposal areas shall be identified on the proposal map, be within the permit area, and they must be approved by the Secretary as suitable for construction of spoil piles. The disposal area shall be located on the most moderate slopes and naturally stable areas available.9.4.b. Drainage. -- The disposal area shall not contain springs, natural water courses or wet weather seeps unless lateral drains are constructed from the wet areas to under drains in such a manner that infiltration of the water into the spoil pile shall be prevented. The drains shall be designed and constructed of coarse rock. If no filter is designed for an under drain, sufficient capacity shall be provided to allow for partial plugging of the drain. No rock shall be used in under drains if it tends to disintegrate or if it is acid-forming or toxic-forming.9.4.c. Construction. -- Construction of the spoil pile shall be as follows:9.4.c.1. All areas upon which the spoil pile is to be placed shall first be progressively cleared of all trees, brush, and shrubs. This material shall be removed from the area of the spoil pile;9.4.c.2. All material shall be deposited in uniform horizontal layers and compacted with haulage equipment;9.4.c.3. Unless waived by the Secretary based upon a stability analysis of the spoil pile, the thickness of the layers shall not exceed four (4) feet; and9.4.c.4. The outer slope or face of the spoil pile shall be regraded to be no steeper than two (2) horizontal to one (1) vertical (2:1) Provided; that constructed slopes may be steeper if they meet a static safety factor of one point five (1.5) and are certified quarterly during construction by a registered professional engineer. The spoil pile shall be considered dormant and shall not need to be certified during periods of inactivity that exceed ninety (90) days in length. Benches shall be constructed on the spoil pile at a maximum of every fifty feet (50') in vertical rise above the toe of the spoil pile. The benches shall be no less than twenty feet (20') in width, and slope toward the pile at a three (3) to five (5) percent grade, and slope laterally at one (1) percent grade to discharge channels design in accordance with section 7 of this rule; and9.4.c.5. When construction of a spoil pile is completed, topsoil or other suitable material which will support vegetation shall be spread over the completed slopes and benches. The slopes and benches shall then be seeded and mulched immediately in accordance with the approved revegetation plans.9.5. Temporary Spoil Storage Areas - Temporary spoil storage areas must be approved by the Secretary as suitable for construction of a fill. The storage area shall be located on the most moderate slopes and naturally stable areas available. Temporary spoil storage areas constructed on slopes steeper than twenty (20) degrees shall be designed using those same requirements as permanent excess spoil disposal sites.9.6. Variance. -- Where it can be demonstrated that other design criteria are justified, certain requirements of this section may be waived. The basis for justification is, but not limited to, land use potential, access to mineral reserves, unavailability of durable rock, and site stability.