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COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT, Water Quality Control Division <br />Rationale, Page 3, COG-0850000 Coal Mining General Permit <br />Table III-2a: Effluent Limitations and Monitoring Requirements - Alkaline Drainage, Coal Preparation Plants and Coal <br />' Preparation Plant Associated Areas and Western Alkaline Coal Mining (additional requirements apply to Western <br />Coal Mining, See Section III.A.3 of this rationale) <br />' - r?lllntttati?n5- _._..__..__.. Monitoring Sample <br />Palumeter . 30 Day 7-Day Daily Rationale t <br />Fr-equeni }y T)Pe ' <br />General Permit Requirements <br />' Flow, MOD Continuous / Recorder / <br />Report NA Report Discharge Evaluation Instantaneous-' In-situ 2 <br />PH, S.U. N/A NA 65-9.0 Water Quality Standards Weekly Grab <br />Oil and Grease, mg/1 N/A NA 10 State Effluent Regulations Weekly Visual j <br />Federal Effluent Limitation Guidelines <br />Total Suspended Solids, mg11 35 NA 70 Federal ELG Weekly Grab <br />Total Iron, mg17 <br />' Existing Sources (before 514184) 3.5 NA 7.0 Federal ELG Weekly Grab <br />New Sources (after 514184) 3.0 NA 6.0 <br />Settleable Solids, m117 Report NA 0.5 Federal ELG Weekly Grab <br />' Site Specific Limitations <br />Total Dissolved Solids, mg11 • Report NA Report Salinity Regulations Quarterly 4 Grab <br />Total Phosphorus (as P), mg11 •• Report NA Various Control Regulations Monthly . Grab <br />Total Recoverable Iron, ug17 *** 1000 NA NA Water Quality Standards Weekly Grab <br />' Other Pollutants of Concern Various NA Various Water Quality Standards Weekly Grab <br />Whole Effluent Toxicity (WET) <br />Chronic Stat Diff and IC25 > IWC State Permit Limitations Quarterly 3I Grab/Test <br />' Acute LC50 > 100% State Permit Limitations Grab <br />Footnotes 1-4, ! and «= See Footnotes under Table Ill-1 <br />«:« This limitation will apply and will substitute for the 30-day average total iron limit based upon the ELG, when a total recoverable iron standard is applicable to the <br />i stream segment. <br />Alternate Limitations For Alkaline Mine Drainage, Coal Preparation and Associated Areas and Western Alkaline Coal <br />Mining - Table III-2b contains limitations for any discharge or increase in the volume of a discharge from an above ground <br />alkaline mine (or an underground alkaline mine where the effluent is commingled with other categorical wastewater prior to <br />discharge), caused by precipitation within any 24-hour period less than or equal to the 10-year. 24-hour precipitation event <br />' (or snowmelt of equivalent volume) Ma substitute the following limitations for these specific parameters only, subject to <br />burden ofproof requirements described in Part LB.4 of the permit. <br />i <br />Table Ill-2b: 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 Mini, See Section IIL A.3 of this rationale) <br />,,_ - - - - - - - -- - <br />. Liniitutiot?s <br />' 30= ' 7-Dav Dai1v . Monitoring Sample <br />Parameter .5 Rationale <br />Day " Avg. Alax.- Frequency t Type <br />_ ._Dg? <br />Federal Effluent Limitation Guidelines <br />' Total Suspended Solids, mg11 Report NA Report Federal ELG Weekly Grab <br />Totallron, mg11 <br />Existing Sources (before 514184) Report NA Report Federal ELG Weekly Grab <br />' New Sources (after 514184) Report NA Report <br />Alternate Limitations For Alkaline Mine Drainage, Coal Preparation and Associated Areas, and Western Alkaline Coal <br />' Mining - Table III-2c contains limitations for any discharge or increase in the volume of a discharge from an above ground <br />alkaline mine (or an underground alkaline mine where the effluent is commingled with other categorical wastewater prior to <br />discharge), caused by precipitation within any 24-hour period greater than the 10-year. 24-hour precipitation event (or <br />snowmelt of equivalent volume) may substitute the following limitations for these specific parameters only, subject to burden <br />of proof requirements described in Part I.B.4 of the permit.