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COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT, Water Quality Control Division <br />Rationale, Page 2, COG-0850000 Coal Mining General Permit <br />B. Application <br />Dischargers can apply for coverage under this general permit once the permit is issued. Holders of certifications under the <br />administratively extended Coal Mining Permit (COG-0850000) will automatically be transferred to this new general permit. <br />Their coverage will be transferred to the new general permit without a lapse of coverage (i. e. discharging without a permit) and <br />without loss offee payments. The permittee will have 90 days, from the date of transfer, to comply with any new terms and <br />conditions of this general permit. For all others, the owner or operator of the site shall submit one original completed <br />application and a copy, including a signed certification that the SWMP is complete at least thirty days prior to the <br />commencement of mining activities. <br />III. EFFLUENT LIMITATIONS <br />A. General Effluent Limitations and Monitoring Requirements <br />Numeric efilugnt limitations are imposed for pollutants that are specific to the discharges covered, and are shown in Tables III-1 <br />through III-6. Some of these limits are based on the EPA Federal Effluent Guidelines for the applicable point source <br />category and are described below. The certification will state which conditions apply to which outfalls, based on the nature <br />of the discharge. Note that any parameter that is determined to be a site-specific pollutant of concern may be added to the <br />discharge certification. <br />1. Surface Runo or Non-Coal fining Related Wastestreams - Table III-1 contains the general limitations and monitoring <br />requirements for wastewater from coal mining sites that are not directly related to mining activities. <br />Table III-1: Effluent Limitations and Monitoring Requirements for Outfalls Comprised of Surface Runoff or Non-Coal <br />Mining Related Waste Streams <br />_ <br /> Limitations Monitoring Sample <br />Parameter 30-Day 7-Day Daily Rationale Frequency t Type <br /> A vg Aug:" _ Mai: _ . <br /> General Permit Requirements Continuous / Recorder l <br />Flow, MGD Report NA Report Discharge Evaluation Instantaneous" In-situ , <br />H N/A NA 6.5-9.0 Water Quality Standards Weekly Grab <br />l s <br />, s. u. <br />p <br />Oil and Grease, mg/1 N/A NA 10 State Effluent Regulations Weekly Visua <br /> Federal Effluent Limitation Guidelines <br />G <br />Weekl <br />Grab <br />Settleable Solids, mill <br />* Report NA <br />NA 0.5 <br />Report Federal EL <br />Federal ELG y <br />Weekly Grab <br />Settleable Solids, m111 Report <br /> <br />mg/I " <br />tal Dissolved Solids <br />T Site Specific Lim <br />Report NA itations <br />Report <br />Salinity Regulations <br />Quarterly ° <br />Grab <br />b <br />G <br />, <br />o <br />Total Phosphorus (as P), mg11 Report NA Various Control Regulations Monthly ra <br />Other Pollutants of Concern Various NA Various Water Quality Standards Weekly Grab <br />1- For a minor facility, as determined by the EPA NPDES Permit Rating Worksheet, all weekly monitoring requirements shall be changed to 2 days per month. <br />2 - !f power is not available, flow may be measured on an instantaneous basis. Major facilities shall monitor .flow weekly, minor facilities 2 days / month <br />3 - If a visual sheen is noticed, a grab sample must be taken and analyzed for oil and grease <br />4 - Quarterly monitoring shall be prescribed if the limitation is based upon discharge to the Colorado River Basin. If the limitation is based upon agricultural <br />protection, the monitoring frequency shall be weekly. <br />• If caused by precipitation within any 24-hour period greater than the 10 year, 24-hour precipitation event (or snowmelt of equivalent volume) <br />"* The 7DS limitation will normally apply to discharges in the Colorado River Basin. An evaluation of the discharge will take place upon certification, to see if the <br />facility meets the 1 ton/day or 350 tonslyear allowable discharge of salt. If the facility does not meet this requirement, the facility will tie required to submit a salinity <br />report documenting that achieving this level of discharge is not feasible. See Regulation 61.8(2)(1) for more information. <br />*** The phosphorus limitations apply to discharges to the Dillon Reservoir Wateshed, Cherry Creek Reservoir Watershed, Cha field Reservoir Watershed, and the <br />Bear Creek Watershed, as defined in Regulation 71, 72, 73 or 74 respectively. The permittee may be required to obtain a phosphorus allocation from the applicable <br />control regulation authority prior to certification under this general permit. <br />2. Alkaline Draina a Coal Pre aration Plants and Coal Pre aration Plant Associated Areas and Western Alkaline Coal <br />Minin - Tables III-a, III-b and III-c apply to Alkaline Drainage, Coal Preparation Plants and Coal Preparation Plant <br />Associated Areas and Western Alkaline Coal Mining. These tables cover the basic limitations, as well as alternate <br />limitations based upon precipitation events. These categories are subject to 40 CFR Part 434 Subparts B (Coal Preparation <br />Plant and Associated Areas), D (Alkaline Mine Drainage) and F (Miscellaneous Provisions). These limitations also apply to <br />Western Coal Mining Operations. Additional limitations for Western Coal Mining can be found under Section III.A.3 of this <br />rationale. At a minimum, the following limitations may apply as outlined in these subparts.