PERMFILE115807

• Permit No: C1982057
• IBM Index Class Name: Permit File
• Doc Date: 12/9/2006
• Doc Name: NPDES Discharge Permit CO-0000221
• Section_Exhibit Name: Tab 15 Appendix 15-4
• Media Type: D
• Archive: No

PARTI
Page No. 14
Permit Na: CO-0000
s. outfall WTH (Flow weighted Composite Samples from outfalls 012, 013 a'nd Ol4)
Effluent Parameter Effluent Concentration
Maximum Cmtcentrations
30-Day Average 7-Day Average Daily Maximum
WET, chronic
until ]2/3]/07 NA NA Report
beginning 01/01/08 NA NA Statistical Difference
and IC25 > IWC
The I WC for this outfall dwing the 2"d Quarter is 83°O/a, at all other times the IWC is 100%
t. outfall R'TI (Flow weighted Composite Samples from outfalls 016 and 017)
Effluent Parameter Effluent Concentration
Maximum Concentrations
30-Day Average 7-Day Average Daily Maximum
WET, chronic
unti112/31/07 NA NA Report
beginning O1/01/OS NA NA Statistical Difference
and IC25 > IWC
2. Whole Effluent Toxicity -Chronic Lethality Limitation -
outfalls WTB (outfall 004) and WTE (outfall 008) -Beginning immediately and lasting through the expiration date of the
pemtit; there shall be no statistically significant difference in lethality (a[ the 95% confidence level) between the control and
any effluent concennation less than or equal to 100% effluent. Such limitation shall apply as a daily maximum.
outfalls WTA (outfalls 002 and 003), outfall WTC (Outfa11005), outfall WTD (Outfa11006), outfall WTF (outfall
010), outfall WTG (Outfa11011), and outfall WTI (Outfa11016 and 017) -Beginning January 1, 2008, and lasting -
through the expiration date of the permit, [here shall be no statistically significant difference in lethality (at [he 95%
confidence level) between the control and any effluent concentration less than or equal to 100% effluent. Such limitation
shall apply as a daily maximum. The permittee is required to monitor for WET at these outfalls prior to the effective date of
the limitation.
outfall W"fH (outfalls 012, 013 and 014) -Beginning January I, 2008, and lasting through the expiration date of the
permit, there shall be no statistically significant difference in lethality (at the 95% confidence level) between the control and
any effluent concentration less than or equal to 100% effluent in the 1", 3r° and 4`"quarters; or less than or equal to 83%,
in the Z"" quarter. Such limitation shall apply as a daily maximum. The permittee is required to monitor for WET at these
outfalls prior to the effective date of the limitation.
3. Alternate Limitation Burden of Proof Requirements
The pernittee has the burden of proof when seeking relief from total suspended solids (TSS), total iron and/or settleable
solids (SS) limitations, as applicable. All outfalls are eligible for relief from TSS, total iron and SS, as applicable; however,
the majority of the loading from any discharge has to consist of storm runoff for the relief to be available. The permittee wilt
need to show that exceedance of the applicable limitations was caused by precipitation (surtace runoff water) and not mine
water or spoils spring water, through a comparison of the loading from each source. outfalls 009 and Oli are eligible for
relief from TSS, total iron and SS on the basis that only surface nmoff discharges are authorized from these outfalls.
Relief maybe granted for each discharge occur ence only when necessary and shall not be granted when the permittee has
control over the discharge, The permittee should endeavor to meet the primary limitations whenever possible.
a. Por naive outfalls: For rainfall, to waive TSS and total iron limitations, it is necessary to prove that discharge occurred
within 48 hours after measurable precipitation has stopped. In addition, to waive settleable solids limitations, it is
necessary [o prove that discharge occun-ed w~idrin 48 hours after precipitation greater than the 10-year, 24-hour event has
stopped. For snowmelt, to waive TSS and total iron limitations, it is- necessary to prove that discharge occurred within