PERMFILE103125

• Permit No: C1982056
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: Tipple EXHIBIT 10 NPDES PERMIT
• Media Type: D
• Archive: No

PART I
Page No. 5
Permit No. CO-0036684
~A. DEFINITION OF EFFLUENT LBtfITATIONS
4. Post-Minine Areas
Commencing at the time active mining has ceased and surface azeas have been re[utned to the required contour all
applicable discharges may be eligible for limitations other than those specified in Pan I.A.I. In most cases, these
post-mining limitations shall remain in effect until bond release. The permittee shall notify [he Division upon cessation
of active mining so [ha[ consideration of appropriate permit modifications can be made.
5. Chronic WET Testine - Outfall 001
a. Testine and Reoortine Requirements
Tests shall be done at the frequency listed in Part I.B.I. Test results shall be reported on the Discharge
Monitoring Report (DMR) submitted for the reporting period during which the sample was taken. (i.e., WET testing
results for [he first calendar quaver ending March 31 shall be reported with the DMR due April 28.) The results
shall be submitted on the Chronic Toxicity Test report form, available from the Division. Copies of these reports
are to be submitted to both the Division and EPA along with the DMR.
The permit[ee shall conduct each chronic WET test in general accordance with methods described Short Term
Methods for Estimative the Chronic Toxicity of Effluents and Receivine Waters to Freshwater Organisms,
EPA/600/4-89/OOl or the most current edition, ezcep[ as modified by the most current Division guidance document
entitled Guidelines for Conductive Whole Effluent Toxicity Tests. The permittee shall conduct such tests using
Ceriodaphnia dubia and fathead minnows.
b. Failure of Test and Division Notification
• Beginning on the effective date of the limitation, a chronic WET test is failed whenever there is a statistically
significant difference in lethality between the control and any effluent concentration less than or equal to the
instream waste concentration ("IWC"). The IWC for this permit has been determined to be 74%. The pertnittee
must provide written notification of the failure of a WET test to the Division, along with a statement as to whether a
Preliminary Toxicity Investigation ("PTI")/Toxicity Identification Evaluation ("TIE") or accelerated testing is being
performed. Notification must be received by the Division within 21 calendar days of the demonstration of
chronic WET in the routine required test. "Demonstration" for the purposes of Parts I.A.6.b., c., d. and f.
means no later than the last day of the laboratory test.
c. Automatic Comuliance Schedule Upon Failure of Test
If a routine chronic WET [es[ is failed, [he following automatic compliance schedule shall apply. As pan of this the
permit[ee shall either:
(i) proceed to conduct the PTI/TIE investigation as described in Pan I.A.4.e, or
(ii) conduct accelerated testing using the single species found [o be more sensitive.
IC accelerated testing is being performed, the permittee shall provide written notification of the results within
14 calendar days of completion of the "Pattern oC Toxicity"/"No Toxicity" demonstration. Testing will be at
least once every two weeks for up to five tests until; 1) two consecutive tests fail or three of five tests fail, in which
case a pattern of toxicity has been demonstrated or 2) two consecutive tests pass or three of five tests pass, in which
case no pattern of toxicity has been found. If no pattern of toxicity is found the toxicity episode is considered to be
ended and routine testing is to resume. If a pattern of toxicity is found, aPTI/TIE investigation is to be performed.
If a pattern of toxicity is not demonstrated but a significant level of erratic toxicity is found, the Division may
. require an increased frequency of routine monitoring or some other modified approach.
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