4 Va. Admin. Code § 25-130-817.107
Current through Register Vol. 41, No. 8, December 2, 2024
Section 4VAC25-130-817.107 - Backfilling and grading; steep slopes(a) Underground mining activities on steep slopes shall be conducted so as to meet the requirements of 4VAC25-130-817.102 through 4VAC25-130-817.106 and the requirements of this section.(b) The following materials shall not be placed or allowed to remain on the downslope: (2) Waste materials of any type.(3) Debris, including that from clearing and grubbing.(4) Abandoned or disabled equipment.(c) Land above the highwall shall not be disturbed unless the division finds that this disturbance will facilitate compliance with the environmental protection standards of this Subchapter and the disturbance is limited to that necessary to facilitate compliance.(d) Woody materials shall not be buried in the backfilled area unless the division determines that the proposed method for placing woody material within the backfill will not deteriorate the stable condition of the backfilled area.(e) The permittee must demonstrate to the division, using standard geotechnical analysis, that the minimum static factor of safety for the stability of all portions of the reclaimed land is at least 1.3. A lower or higher factor of safety may be specified by the division upon a finding that the backfilled area will not present any actual or probable hazard to public property, health, safety, and the environment. The factor of safety specified shall be based on accepted geotechnical engineering analyses. A lower factor of safety shall be approved only upon a demonstration that:(i) The degree of uncertainty in the calculation has been reduced through the use of thorough geotechnical testing and analyses. Sufficient investigation and laboratory testing shall be conducted to determine the design requirements for stability of the backfilled area. The testing and analyses shall include at a minimum consideration of the properties of the spoil to be backfilled, foundation conditions, and surface and groundwater flows.(ii) The backfilled area will not present any actual or probable hazard to public health and safety or the environment.(iii) A system of underdrains is utilized to assure that the phreatic surface within the backfilled area is controlled. The underdrains shall be constructed of non-degradable, non-acidic or toxic-forming material such as natural sand and gravel, sandstone, or other durable rock that will not slake in water and which is essentially free of coal, clay, or shale. The internal drainage system must ensure continued free drainage of anticipated seepage from precipitation and from springs or wet weather seeps. The drain size shall be designed to safely route the anticipated seepage flows over the long term life of the backfilled area.(iv) The design shall be certified by a qualified registered professional engineer experienced in the construction of earth and rockfill embankments as being in conformance with accepted professional standards.(v) The backfilled area shall be inspected by a qualified registered professional engineer or other qualified professional specialist experienced in the construction of earth and rock-fill embankments during critical construction periods. The registered engineer shall provide to the division a certified report within two weeks after each inspection that the backfilled area has been constructed as specified in the design approved by the division.(f) Drainage channels or roads which are approved under 4VAC25-130-817.133 for the postmining land use and which are to be located in the uppermost portion of the backfilled area shall be approved by the division only upon a finding that the highwall shall be completely covered. The division may approve incorporating the drainage channel or road as an integral part of the backfilled area with the requirement to blend or shave the highwall into the natural terrain, if the standards of this section are satisfied.4 Va. Admin. Code § 25-130-817.107
Derived from VR480-03-19 § 817.107, eff. December 15, 1981; amended, eff. June 28, 1982; October 28, 1982; December 14, 1982; October 11, 1983; December 27, 1983; May 8, 1984; June 22, 1984; August 2, 1984; October 16, 1985; January 7, 1987; July 22, 1987; November 25, 1987; October 12, 1988; December 26, 1990; July 1, 1991; July 17, 1991; November 20, 1991; July 7, 1992; May 5, 1993; October 19, 1994.Statutory Authority
§§ 45.1-161.3 and 45.1-230 of the Code of Virginia.