GUIDELINES FOR MINIMIZING THE EFFECTS OF SURFACE MINING AND
SURFACE EFFECTS OF UNDERGROUND MINING ON WATER QUALITY

Recognizing that there are wide variations in the circumstances and conditions surrounding and arising out of the strip mining and underground mining processes, such variables include but not limited to topography, climatic conditions, location of material deposits and soil types, the rules adopted by the Department are of a broad, general nature. They have been designed to provide flexibility to both the Department and the mine operator in preparing a plan of operation with each plan being tailored to a specific set of conditions. The following guidelines should be used as minimum criteria in formulating any pollution abatement and/or prevention plan required by Rule 335-6-9-.03 adopted by the Department and for any plan which the technical staff may require to minimize the surface effects of underground mining on water quality.

APPENDIX A

Sedimentation Controls

1. (1) Pollution abatement facilities should be designed and constructed so as to control both spoil runoff and pit drainage.
2. (2) Pit drainage and spoil runoff should be diverted through the sedimentation basin by means of diversion ditches or normal drainage patterns. In cases where it is not practical to use this system, then natural vegetation, vegetative windrows, hay berms, earthen berms or other equally effective systems may be utilized.
3. (3) The sediment basin should have a minimum capacity to store 0.25 acre feet/acre of disturbed area in the drainage area. The basin shall be cleaned out when the sediment accumulation approaches 60 percent of the design capacity. All trees, boulders and other obstructions must be removed from the basin during the initial construction phase to facilitate clean-out.

4. (4) The dam for the sediment basin should be designed and built using the following as minimum criteria:

   1. (a) the top of the dam should be no less than 12 feet wide.
   2. (b) the slope on either side of the dam should be no steeper than 3:1.
   3. (c) the dam should be constructed wide a cutoff trench at least 8 feet wide. The side slopes should be no less than 1:1. The cutoff trench shall be located on the dam centerline and be of sufficient depth (not less than 2 feet) to extend into a relatively impervious layer of soil or to bedrock and shall be filled with a relatively impervious material from which the core of the dam shall be constructed.
   4. (d) the entire embankment and cutoff trench shall be compacted to 95 percent density, based on standard proctor as outlined in ASTM.
   5. (e) the material placed in the embankment should be free to sod, roots, stones over 6 inches in diameter and other objectionable materials. The fill material should be placed and spread over the entire fill area, starting at the lowest point of the foundation, in layers not to exceed 12 inches in thickness. Construction of the fill should be undertaken only at such times that the moisture content of the fill material will permit satisfactory compaction in accordance with subparagraph (4)(d) above.
   6. (f) the spillpipe should be seized to adequately carry the expected peak flow from a one-year frequency storm.
   7. (g) the spillpipes should be made of a material capable of withstanding chemical reactions caused by the quality of the water being discharged.
   8. (h) the spillpipe should be equipped with a device, or constructed, such to ensure that subsurface withdrawal is accomplished in order to ensure that no floating solids are discharged.
   9. (i) the spillpipes should be equipped with anti-seep collars at each joint which radiate at least 2 feet from the pipe in all directions. The collars and their connections to the pipe should be watertight.
   10. (j) a splash pad or riprap should be placed under the discharge of the spillpipe, or the location of the discharge set, so as to ensure that the discharge does not erode the dam.
   11. (k) the emergency spillway should be designed to safely carry the expected peak flow from a 25 year, 24 hour storm or shorter duration. When designing spillways that are in the drainage course of a public water supply, then 50 years, 24 hour or shorter duration data should be used. The slope of the entrance and exit to the emergency overflow should not exceed 3 percent. The emergency overflow should be constructed with a control section at least 20 feet long. The side slopes of the emergency overflow should not be steeper than 2:1. The emergency overflow should be riprapped or concreted in order to prevent erosion.
   12. (l) there should be a minimum of 1 1/2 feet of freeboard between the normal overflow and the emergency overflow. There should be at least 1 1/2 feet of freeboard between the maximum design flow elevation in the emergency overflow and the top of the dam.
   13. (m) if basins are built in series, then the emergency overflow for each should be designed to accommodate the entire drainage area.
   14. (n) the dam should be sowed with both perennial and annual grasses in order to ensure erosion is minimized. Hay bails or riprap should be placed at the toe of the dam immediately upon completion of construction.

5. (5) Areas in which surface mined minerals are stockpiled, and areas in which refuse resulting from any type of mining operation is or has been deposited, should be provided with diversion ditches or other appropriate methods of intercepting surface water in such a way as to minimize the possibility of sediment laden, acidic or toxic waters from such areas, being deposited into a stream.

   APPENDIX B

   Haul Roads

6. (1) In order to minimize sediment from haul roads:

   1. (a) no sustained grade should exceed 10 percent;
   2. (b) the maximum grade should not exceed 15 percent for 300 feet;
   3. (c) there should not be more than 300 feet of 15 percent maximum grade for each 1,000 feet of road constructed;
   4. (d) the haul road, wherever possible, should be located so that runoff from the road enters a sediment basin constructed for the mining operation.
   5. (e) outer slopes for haul roads out of the permitted area should not be steeper than 2:1 and should be seeded with annual and perennial grasses with at least 80 percent cover to avoid erosion. Where this is not possible, basins, hay filters or diversion ditches should be cut, built or placed to intercept runoff. Details outlining control measures must be included with the abatement plan.
7. (2) Stream crossings should be avoided; however, any crossings which are necessary and which meet technical staff approval should be detailed with drawings and any other pertinent data in the pollution abatement plan, using best engineering practices.

Author: ADEM

Statutory Authority: Code of Ala. 1975,