Section 817.41. Hydrologic-balance protection

(a) General. All underground mining and reclamation activities shall be conducted to minimize disturbance of the hydrologic balance within the permit and adjacent areas, to prevent material damage to the hydrologic balance outside the permit area, and to support approved postmining land uses in accordance with the terms and conditions of the approved permit and the performance standards of this part. The division may require additional preventative, remedial, or monitoring measures to assure that material damage to the hydrologic balance outside the permit area is prevented. Mining and reclamation practices that minimize water pollution and changes in flow shall be used in preference to water treatment.

(b) Groundwater protection. In order to protect the hydrologic balance, underground mining activities shall be conducted according to the plan approved under 4VAC25-130-784.14(g) and the following:

(1) Groundwater quality shall be protected by handling earth materials and runoff in a manner that minimizes acidic, toxic, or other harmful infiltration to groundwater systems and by managing excavations and other disturbances to prevent or control the discharge of pollutants into the groundwater.

(2) Groundwater quantity shall be protected by handling earth materials and runoff in a manner that will restore approximate premining recharge capacity of the reclaimed area as a whole, excluding coal mine waste disposal areas and fills, so as to allow the movement of water to the groundwater system.

(c) Groundwater monitoring.

(1) Groundwater monitoring shall be conducted according to the groundwater monitoring plan approved under 4VAC25-130-784.14(h). The division may require additional monitoring when necessary.

(2) Representative monitoring.

(i) Representative monitoring points shall be established within 100 feet downgradient from the initial disturbance within each representative area. This distance may be modified by the division if it is demonstrated in the permit application that the 100 feet distance is inappropriate for the monitoring point.

(ii) If degradation, contamination or diminution of water quality or quantity are evident through monitoring, then additional monitoring and/or remedial action may be required by the division.

(3) Source monitoring.

(i) Source monitoring shall be used near isolated acid-producing or toxic-producing material. Monitoring shall be by piezometers or other equipment suitable for monitoring in the unsaturated zone. Piezometers or alternate equipment shall be installed in backfilled material during or within 45 days after final grading of the area. Installation in fill or temporary storage areas shall be as soon as practicable. Monitoring points shall be of sufficient number and locations so that adverse impacts can be readily detected.

(ii) Representative monitoring may be required by the division in addition to source monitoring when the operation may adversely impact usable ground waters.

(4) Well drilling, construction and completion.

(i) When wells are used, they shall be drilled either to the first water-producing zone or, if no water is encountered, to a depth of 100 feet below each coal seam to be mined. The division may require deeper drilling if site conditions indicate the potential for adverse impacts to a known water-producing zone which is at greater depth.

(ii) Monitoring wells shall be drilled an additional 20 feet into the water-producing zone to aid in pumping.

(iii) Monitoring wells shall:

(A) Accommodate a four-inch submersible pump for sample extraction and measurement of field parameters. Other diameters may be approved by the division if sample extraction is allowed.

(B) Be constructed in a manner which isolates the water-producing zone to be monitored and prevents the mixing of ground waters.

(C) Be grouted from the surface to at least one foot into bedrock, with all leakage around the well casing prevented.

(D) Be capped, locked, and labeled with an identification number.

(E) Be properly developed and the final yield reported.

(F) Not be constructed or packed with materials which would adversely affect the monitoring results obtained.

(iv) Existing wells may be used for monitoring provided that:

(A) The well is located at a point where data representative of the permit or adjacent area will be obtained.

(B) The well penetrates the water-producing zone to be monitored.

(C) The well is constructed in a manner which effectively isolates the water-producing zone.

(D) The well meets the standards of subdivision (c)(4) of this section.

(E) Filtering systems and water softeners are not present which may alter the quality of the water sample. Filters or softeners may be disconnected or bypassed during sampling.

(5) Groundwater monitoring data shall be submitted within 30 days after the end of the calendar quarter to the division. More frequent reporting may be prescribed by the division. Monitoring reports shall include analytical results from each sample taken during the reporting period. When the analysis of any groundwater sample indicates noncompliance with the permit conditions, then the permittee shall promptly notify the division and immediately take the actions provided for in 4VAC25-130-773.17(e) and 4VAC25-130-784.14(g).

(6) Groundwater monitoring shall proceed through mining and continue during reclamation until bond release. Consistent with the procedures of 4VAC25-130-774.13, the division may modify the monitoring requirements including the parameters covered and the sampling frequency if the permittee demonstrates, using the monitoring data obtained under this subdivision, that:

(i) The operation has minimized disturbance to the prevailing hydrologic balance in the permit and adjacent areas and prevented material damage to the hydrologic balance outside the permit area; water quantity and quality are suitable to support approved postmining land uses; or

(ii) Monitoring is no longer necessary to achieve the purposes set forth in the monitoring plan approved under 4VAC25-130-784.14(h).

(7) Equipment, structures, and other devices used in conjunction with monitoring the quality and quantity of groundwater onsite and offsite shall be properly installed, maintained, and operated and shall be removed by the permittee when no longer required by the division.

(d) Surface water protection. In order to protect the hydrologic balance, underground mining activities shall be conducted according to the plan approved under 4VAC25-130-784.14(g), and the following:

(1) Surface water quality shall be protected by handling earth materials, groundwater discharges, and runoff in a manner that minimizes the formation of acidic or toxic drainage; prevents, to the extent possible using the best technology currently available, additional contribution of suspended solids to streamflow outside the permit area; and otherwise prevents water pollution. If drainage control, restabilization and revegetation of disturbed areas, diversion of runoff, mulching, or other reclamation and remedial practices are not adequate to meet the requirements of this section and 4VAC25-130-817.42, the permittee shall use and maintain the necessary water-treatment facilities or water quality controls.

(2) Surface water quantity and flow rates shall be protected by handling earth materials and runoff in accordance with the steps outlined in the plan approved under 4VAC25-130-784.14(g).

(e) Surface water monitoring.

(1) Surface water monitoring shall be conducted according to the surface water monitoring plan approved under 4VAC25-130-784.14(i). The division may require additional monitoring when necessary.

(2) Surface water monitoring data shall be submitted every three months to the division or more frequently as prescribed by the division. Monitoring reports shall include analytical results from each sample taken during the reporting period. When the analysis of any surface water sample indicates noncompliance with the permit conditions, the permittee shall promptly notify the division and immediately take the actions provided for in 4VAC25-130-773.17(e) and 4VAC25-130-784.14(g). Reporting shall be in accordance with the National Pollutant Discharge Elimination System (NPDES) permit requirements.

(3) Surface water monitoring shall proceed through mining and continue during reclamation until bond release. Consistent with 4VAC25-130-774.13, the division may modify the monitoring requirements, in accordance with the NPDES permit, including the parameters covered and sampling frequency, if the permittee demonstrates, using the monitoring data obtained under this subdivision, that

(i) The operation has minimized disturbance to the hydrologic balance in the permit and adjacent areas and prevented material damage to the hydrologic balance outside the permit area; water quantity and quality are suitable to support approved postmining land uses; and

(ii) Monitoring is no longer necessary to achieve the purposes set forth in the monitoring plan approved under 4VAC25-130-784.14(i).

(4) Equipment, structures, and other devices used in conjunction with monitoring the quality and quantity of surface water onsite and offsite shall be properly installed, maintained, and operated and shall be removed by the permittee when no longer required by the division.

(f) Acid- and toxic-forming materials.

(1) Drainage from acid- and toxic-forming materials and underground development waste into surface water and ground water shall be avoided by:

(i) Identifying and burying and/or treating, when necessary, materials which may adversely affect water quality, or be detrimental to vegetation or to public health and safety if not buried and/or treated; and

(ii) Storing materials in a manner that will protect surface water and ground water by preventing erosion, the formation of polluted runoff, and the infiltration of polluted water. Storage shall be limited to the period until burial and/or treatment first become feasible, and so long as storage will not result in any risk of water pollution or other environmental damage.

(2) Storage, burial or treatment practices shall be consistent with other material handling and disposal provisions of this chapter.

(g) Transfer of wells. Before final release of bond, exploratory or monitoring wells shall be sealed in a safe and environmentally sound manner in accordance with 4VAC25-130-817.13 and 4VAC25-130-817.15. With the prior approval of the division, wells may be transferred to another party, or retained by the permittee for further use. However, at a minimum, the conditions of such transfer shall comply with state and local laws and the permittee shall remain responsible for the proper management of the well until bond release in accordance with 4VAC25-130-817.13 through 4VAC25-130-817.15.

(h) Discharges into an underground mine.

(1) Discharges into an underground mine are prohibited, unless specifically approved by the division after a demonstration that the discharge will:

(i) Minimize disturbance to the hydrologic balance on the permit area, prevent material damage outside the permit area and otherwise eliminate public hazards resulting from underground mining activities;

(ii) Not result in a violation of applicable water quality standards or effluent limitations;

(iii) Be at a known rate and quality which shall meet the effluent limitations of 4VAC25-130-817.42 for pH and total suspended solids, except that the pH and total suspended solids limitations may be exceeded, if approved by the division; and

(iv) Meet with the approval of the Mine Safety and Health Administration.

(2) Discharges shall be limited to the following:

(i) Water;

(ii) Coal-processing waste;

(iii) Fly ash from a coal-fired facility;

(iv) Sludge from an acid-mine drainage treatment facility;

(v) Flue-gas desulfurization sludge;

(vi) Inert materials used for stabilizing underground mines; and

(vii) Underground mine development wastes.

(3) Water from one underground mine may be diverted into other underground workings according to the requirements of this section.

(i) Gravity discharges from underground mines.

(1) Surface entries and accesses to underground workings shall be located and managed to prevent or control gravity discharge of water from the mine. Gravity discharges of water from an underground mine, other than a drift mine subject to subdivision (i)(2) of this section, may be allowed by the division if it is demonstrated that the untreated or treated discharge complies with the performance standards of this part and any additional NPDES permit requirements.

(2) Notwithstanding anything to the contrary in subdivision (i)(1) of this section, the surface entries and accesses of drift mines first used after December 15, 1981, or the implementation of a federal lands program in accordance with Part 740 of this chapter, and located in acid-producing or iron-producing coal seams shall be located in such a manner as to prevent any gravity discharge from the mine.

(3) Except where surface entries and accesses to underground workings are located pursuant to subdivision (i)(1) of this section, an unmined barrier of coal shall be left in place where the coal seam dips toward the land surface. The unmined barrier and associated overburden shall be designed to prevent the sudden release of water that may accumulate in the underground workings.

(i) The applicant may demonstrate the appropriate barrier width and overburden height by either:

(A) Providing a site specific design, certified by a licensed professional engineer, which considers the overburden and barrier characteristics; or

(B) Providing the greater of an unmined horizontal barrier width necessary to leave a minimum of 100 feet of vertical overburden, or an unmined barrier width calculated by the formula: W=50 + H, when W is the minimum width in feet and H is the calculated hydrostatic head in feet.

(ii) An exception to the barrier requirement may be approved provided the division finds, based upon the geologic and hydrologic conditions, an accumulation of water in the underground workings cannot reasonably be expected to occur or other measures taken by the applicant are adequate to prevent the accumulation of water.

(j) Drinking, domestic or residential water supply. The permittee must promptly replace any drinking, domestic or residential water supply that is contaminated, diminished or interrupted by underground mining activities conducted after October 24, 1992, if the affected well or spring was in existence before the date the division received the permit application for the activities causing the loss, contamination or interruption. The baseline hydrologic information required in 4VAC25-130-784.14 and the geologic information concerning baseline hydrologic conditions required in 4VAC25-130-784.22 will be used to determine the impact of mining activities upon the water supply.

Historical Notes

Derived from VR480-03-19 § 817.41, 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; Volume 13, Issue 11, eff. March 19, 1997; Volume 14, Issue 05, eff. December 24, 1997.

Statutory Authority

§§ 45.1-161.3 and 45.1-230 of the Code of Virginia.