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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 peniiit. <br />Their coverage will be transferred to the new general permit without a lapse of coverage (i.e. discharging without apermit) and <br />without loss of fee 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 />Ill. EFFLUENT LIMITATIONS <br />' A. General Effluent Limitations and Monitoring Requirements <br />Numeric effluent limitations are imposed for pollutants that are specific to the discharges covered, and are shown in Tables III-I <br />through III-8. 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 Runoffor Non-Coal Mining 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 />lrableIH-1: Effluent Limitations and Monitoring Requirements for Outfalls Comprised of Surface Runoff or Non-Coal <br />Minim Related Waste Streams <br />Limitations rVlonitorirtg Sample <br />36 7-Day Daily Rationale cy t T? e <br />_ F en p <br />Parameter3 rqu <br />_ IV <br />- General Permit Requirements <br />Flow, MGD Continuous / Recorder l <br />I Report NA Report Discharge Evaluation Instantaneous In-situ ' <br />pH, s. u. N/A NA 6.5-9.0 Water Quality Standards Weekly Grab <br />Oil and Grease, mg/1 N/A NA 10 State Effluent Regulations Weekly Visual s <br />Federal Effluent Limitation Guidelines <br />Settleable Solids, ml/1 Report NA 0.5 Federal ELG Weekly Grab <br />Settleable Solids, ml/I * Report NA Report Federal ELG Weekly Grab <br />-Site Specific Limitations <br />Total Dissolved Solids, mg17 Report NA Report Salinity Regulations Quarterly ° Grab <br />Total Phosphorus (as P), mg17 Report NA Various Control Regulations Monthly Grab <br />Other Pollutants of Concern Various NA Various Water Quality Standards Weekly Grab <br />I - 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 - If 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 monitoringfrequency 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 TDS 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 I ton/day or 330 tonsfyear allowable discharge of salt If the facility does not meet this requirement, the facility will be 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 Feld Reservoir Watershed, and the <br />Bear Creek Watershed, as defined in Regulation 71, 72, 73 or 74 respectively. The permittee maybe 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 LU-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.