2012-06-20_PERMIT FILE - C2010089 (57)

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;OLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT, Water Quality Control Division Rationale, Page 2, COG - 0850000 Coal Mining General Permit =I3. Application Dischargers can apply for coverage under this general permit once the permit is issued. Holders of certifications under the administratively extended Coal Mining Permit (COG - 0850000) will automatically be transferred to this new general permit. Their coverage will be transferred to the new general permit without a lapse of coverage (Le discharging without a permit) and without loss offee payments. The permittee will have 90 days, from the date of transfer, to comply with any new terms and •• . conditions of this general permit. For all others, the owner or operator of the site shall submit one original completed application and a copy, including a signed certification that the SWMP is complete at least thirty days prior to the commencement of mining activities. III.- EFFLUENT LIMITATIONS ` ''A. General Effluent Limitations and Monitoring Requirements Numeric effluent limitations are imposed for pollutants that are specific to the discharges covered, and are shown in Tables III -1 through III -6. Some of these limits are based on the EPA Federal Effluent Guidelines for the applicable point source • category and are described below. The certification will state which conditions apply to which outfalls, based on the nature of the discharge. Note that any parameter that is determined to be a site - specific pollutant of concern may be added to the discharge certification. 1. Surface Runoff or Non -Coal Mining Related Wastestreams — Table III -1 contains the general limitations and monitoring requirements for wastewater f•orn coal mining sites that are not directly related mining activities. Table III -1: Effluent Limitations and Monitoring Requirements for Outfalls Comprised of Surface Runoff or Non -Coal Mining Related WasteStretina ----- _----- _-- _ ------ ---- _ - - - - -- General Permit Requirements Report Discharge Evaluation Flow, MGD pH, s.u. Oil and Grease, mg/l Settleable Solids, mill Settleable Solids, ntl/1 >i< Report NA NIA NA 6.5 -9.0 Water Quality Standards N/A NA 10 State Effluent Regulations Federal Effluent Limitation Guidelines ----- Report NA 0.5 Federal ELG Report NA Report Federal ELG Continuous / Instantaneous Weekly Weekly Weekly Weekly __- - - -___ - Specific Lirnitattons--------- -_-- __-- ..________— uarterl 4 Total Dissolved Solids, mg/l ** Report NA Report Salinity Regulations Q Y Total Phosphorus (as P), rng/l * ** Report NA Various Control Regulations Monthly Other Pollutants of Concern Various NA ; Various Water Quality Standards Weekly Recorder / In -situ 2 Grab Visual 3 Grab Grab Grab Grab Grab 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. 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 3 — If a visual sheen is noticed, a grab sample must be taken and analyzed for oil and grease 4— Quarterly monitoring shall be prescribed if the limitation is based upon discharge to the Colorado River Basin. lithe limitation is based upon agricultural protection, the monitoring frequency shall be weekly. * If caused by precipitation within any 24 -hour period greater than the 10 year, 24 -hour precipitation event (orsnowmelt of equivalent volume) * * 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 facility meets the 1 ton/day or 350 tons /year allowable discharge of salt. If the facility does not meet this requirement, ohe facility will be required to submit a salinity report documenting that achieving this level of discharge is not feasible. See Regulation 61.8(2)(1) f f * ** The phosphorus limitations apply to discharges to the Dillon Reservoir Wateshed, Cherry Creek Reservoir Watershed, Chatfield Reservoir Watershed, and the Bear Creek Watershed, as defined in Regulation 71, 72, 73 or 74 respectively. The permittee may be required to obtain a phosphorus allocation front the applicable control regulation authority prior to certification under this general permit. . 2. Alkaline Drainage. Coal Preparation Plants and Coal Preparation Plant Associated Areas and Western Alkaline Coal Mining - Tables III -a, III -b and III -c apply to Alkaline Drainage, Coal Preparation Plants and Coal Preparation Plant Associated Areas and Western Alkaline Coal Mining. These tables cover the basic limitations, as well as alternate limitations based upon precipitation events. These categories are subject to 40 CFR Part Subparts B (Coal Preparation Plant and Associated Areas), D (Alkaline Mine Drainage) and F (Miscellaneous Provisions). These limitations also apply to Western Coal Mining Operations. Additional limitations for Western Coal Mining can be found under Section III.A.3 of this rationale. At a minimum, the following limitations may apply as outlined in these subparts.