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COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT, Water Quality Control Division <br />Rationale, Page 4, COG-0850000 Coal Mining General Permit <br />Table III-2c: Alternate Effluent Limitations and Monitoring Requirements - Alkaline Drainage, Coal Preparation Plants and <br />Coal Preparation Plant Associated Areas and Western Alkaline Coal Mining (additional requirements apply to <br />Western Coal Mining, See Section III A.3 of this rationale) <br />Limitations Monitoring :Sample <br />Parameter 30-Day 7-Dv Dail), Rationale, , <br />Fmquetul- Type <br />Avg,_ . Aig, Wax, <br />Federal Effluent Limitation Guidelines <br />Total Suspended Solids, mg11 Report NA Report Federal ELG Weekly Grab <br />Total Iron, mg/1 <br />Existing Sources (before 514184) Report NA Report Federal ELG Weekly Grab <br />New Sources (after 514184) Report NA Report <br />Settleable Solids m111 Report NA Report Federal ELG Weekly Grab <br />3. Effluent Limitations - Western Alkaline Coal Mining - In addition to the requirements under Part LB.1 above, western <br />alkaline coal mines are subject to 40 CFR Part 434 Subpart H. This subpart applies to alkaline mine drainage at western <br />coal mining operations from reclamation areas, brushing and grubbing areas, topsoil stockpiling areas, and regraded areas, <br />where the discharge, before any treatment has a pH equal to or greater than 6.0; has a dissolved iron concentration less <br />than 10 mg/L; and has a net alkalinity that is greater than zero. The effluent limitations in this subpart apply until the <br />appropriate authority has authorized bond release. <br />a. Sediment Control Plan - The following items apply to those facilities, and specifically those areas outlined above. <br />1. The operator must submit a site-specific Sediment Control Plan to the permitting authority that is designed to <br />prevent an increase in the average annual sediment yield from pre-mined, undisturbed conditions. The Sediment <br />Control Plan must be approved by the permitting authority and be incorporated into the permit as an effluent <br />limitation. The Sediment Control Plan must identify best management practices (BMPs) and also must describe <br />design specifications, construction specifications, maintenance schedules, criteria for inspection, as well as <br />expected performance and longevity of the best management practices. <br />2. Using watershed models, the operator must demonstrate that implementation of the Sediment Control Plan will <br />result in average annual sediment yields that will not be greater than the sediment yield levels from pre-mined, <br />undisturbed conditions. The operator must use the same watershed model that was, or will be, used to acquire the <br />SMCRA permit. <br />3. The operator must design, implement, and maintain BMPs in the manner specified in the Sediment Control Plan. <br />b. De nitions - The following definitions are specific to this subpart. <br />1. Brushing and grubbft?area means the area where woody plant materials that would interfere with soil salvage <br />operations have been removed or incorporated into the soil that is being salvaged. <br />2. Regraded area means the surface area of a coal mine that has been returned to required contour. <br />3. Topsoil stockpiling area means the area outside the mined-out area where topsoil is temporarily stored for use in <br />reclamation, including containment berms. <br />4. Reclamation area means an area that was previously disturbed as a part of the coal mining operation that is being <br />reclaimed. <br />4. EEluent Limitations - Post Mining Areas and Reclamation Areas - Post-mining limitations may apply to outfalls serving <br />reclamation areas, which have been returned to the required contour and on which revegetation (seeding or planting) work <br />has commenced. Limitations may also apply to post mining underground mine areas. The permtttee may request <br />consideration for change from active mining limitations to post-mining limitations when these conditions have been met. <br />a. Post Mining Reclamation Areas - Tables III-3a and 111-b apply to this category, subject to 40 CFR Part 434 Subpart <br />E (Post Mining Areas). The following limitations apply to reclamation areas. The federal ELG limitations would apply <br />until bond release. If these wastewaters are combined with other waters under Section III of this rationale, then those <br />limitations shall apply. If this wastewater is combined with post mining underground mine wastewater, then the <br />limitations in Section III.D.2 apply to the combined discharge. If this post mining wastewater is separate, then the <br />following limitations apply.