Laserfiche WebLink
COLORADO DEPARTMENT OF PUBLIC HEALTHAND ENVIRONMENT, Water Quality Control Division <br />Rationale, Page 8, COG-0850000 Coal Mining General Permit <br />Alternate Limitations For Acid Or Ferruginous Mine Drainage From Coal Refuse Piles And From Steep Slope Areas Or <br />Mountaintop Removal Operations -Table III-Se contains limitations for any discharge or increase in the volume of a <br />discharge caused by precipitation within any 24 hoz~r period greater than the 1 year, 24-hour precipitation event, but less <br />than or equal to the 10 year, 24-hour precipitation event (or snowmelt of egz~ivalent volztme) may may substitute the <br />following limitations for these specific parameters only, subject to burden of proof requirements described in Part I.B.4 <br />Table III-Se: Alternate Effluent Limitations and Monitoring Requirements -Acid or Ferruginous Mine Drainage <br />- Limitations . , Monitoring Sample <br />Parameter 30-Day 7-Day Daily Rationale Frequency i Type <br /> Avg::: Avg Max.. . <br />-- -Federal Effluent Ltmitation Gutdelines-------------- yyeekl <br />Y Grab <br />Total Suspended Solids, mg/1 Report NA <br />NA Report Federal ELG <br />Report Federal ELG Weekly Grab <br />Total Manganese, mg/1 Re ort <br />P <br />Totallron, mg/1 <br />Existing Sources (before5/4/84) <br />Report <br />NA <br />Report Federal ELG Weekl <br />Y Grab <br />New Sources (after 5/4/84) Report NA <br />NA Report <br />5 Federal ELG <br />0 Weekl Grab <br />Settleable Solids, ml/1 Re ort . <br />II! OTHER PERMIT CONDITIONS <br />a. Regulafions for Effluent Limitations (Regulation No. 62) -Section 62.4 of the regulations includes e, fluent limitations that apply <br />to all discharges of wastewater to State waters. These regulations are the basis for the oil and grease limitations in the tables <br />above. Note that the limitations for TSS are not inclztded in many cases due to the presence of federal EEGs. <br />b. Technology Based Limitations (Federal Ef)luentLimitation Guidelines) -Federal Efflz~entLimitation Guidelines (EEG's) <br />gz~idelines have been promz~lgated for these faciltttes and must be applted to these discharges, unless a more stringent Water <br />Quality Standard exists. The Water Quality Standards in many areas of the state are often more stringent than the federal <br />EEGs, and therefore may be substituted in a certification. <br />c. Water Quality Standard based Limitations (Discharges to Surface Waters)- Water quality-based limits are imposed for pH. <br />YVater gztality-based reporting may also be imposed for other pollutants of concern based on the discussion that follows. <br />1. ~ -This parameter is limited by Water Quality Standards as the water quality standards of 6.5-9.0 s.u. range are more <br />stringent than those specified under the Regulations for Effluent Limitations. <br />2. Metals -The permit writer will review the application and determine if any metals parameters must be limited and/or <br />monitored to protect the classified uses assigned to the receiving water. If required, the permit writer will set these <br />limitations egz~al to the appropriate wafer-quality standards. As many water quality standards for metals are listed as <br />TVS, and based z~pon an equation dependent on the hardness of the receiving stream, the permit writer will obtain <br />hardness data to determine the appropriate metals limitations where appropriate. If a water quality based limitation for <br />metals is considered in the permit, the more stringent of the federal ELG and the water quality based limit will be <br />applied. <br />3. Organics -The permit writer will review the application and determine if any organic parameters must be limited and/or <br />monitored to protect the classif ed uses assigned to the receiving water. If required, the permit writer will set these <br />limitations equal to the appropriate water-quality standards. <br />4. Chemicals- The addition of chemicals (including release agents) to the discharge is not allowed unless expressly authorized <br />by the Division. If authorized, all chemicals must be used and stored in accordance with the manufacturers' <br />recommendations and in accordance with any applicable state or federal regulation. <br />d. Salinity Requirements -All permit actions for discharges to surface waters in the Colorado River Basin must include salinity <br />monitoring. Accordingly, the permit writer will perform an analysis, as set out to the paragraphs that follow, to determine <br />which salinity requirements apply pursuant to the requirements of Section 61.8(2)(1) of the Colorado Discharge Permit System <br />Re~~lations(Regulation No. 61). Multiple discharges covered from a single facility are subject to the limitation that would <br />apply if there were a single discharge point. <br />Based on the effluent data in the application from a new facility, the permit writer will make an assessment of the expected <br />salinity load in the discharge (from concurrent flows at all outfalls) and if less than 1 ton/day or 366 tons/year, the calculation <br />will be documented in the issz~ed certification. For facilities discharging less than this threshold, quarterly monitoring will be <br />required, as existed in the previous permit. <br />