2006-03-21_PERMIT FILE - C1981022

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PARTI Page No. 5 Permit No.: CO-0000132 2. Alternate Limitation Burden of Proof Requirements The permittee 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 except outfall OIS and 018 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. Relief may be granted for each discharge occurrence only when necessary and shall not be granted when the permi[[ee has control over the discharge. The permittee should endeavor to meet the primary limitations whenever possible. a. For active 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 to prove that discharge occurred within 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 [ha[ discharge occurred within 48 hours after pond inflow has stopped. In addition, to waive settleable solids limitations, it is necessary to prove that discharge occurred within 48 hours after pond inflow volume greater than the 10-year, 24-hour even[ has stopped. b. For cost-mining outfalls: For rainfall, [o waive settleable solids limitations, i[ is necessary to prove that discharge occurred within 48 hours after measurable precipitation has stopped. For snowmelt, to waive settleable solids limitations, it is necessary to prove that discharge occurred within 48 hours after pond inflow has stopped. Should a precipitation event or snowmelt occur, the permittee shall submit adequate proof in order for an exemption to be claimed. Weather station data maybe appropriate in making this demonstration. Said proof shall be submitted as an attachment to the Discharge Monitoring Report (DMR) for the appropriate period. The Division shall determine the adequacy of proof. As part of this determination, the Division shall evaluate whether the permittee could have controlled the discharge in such a manner that primary limitations could have been met. All manual dewatering of ponds that are equipped with automatic dewatering systems must meet TSS and total iron limitations. If a pond has only manual dewatering capability, relief is available only to the extent required to regain necessary stability and capacity. 3. Post-Mining Areas In conformance with 40 CFR 434.50, commencing at the time active mining has ceased and all surface areas served by a sedimentation pond have been returned to the required contour and revegetation has commenced, applicable discharges may be eligible for post-mining limitations. In most cases, these post-mining limitations shall remain in effect until bond release. The permi[[ee shall notify the Division at the appropriate time so that consideration of permit modifications can be made. Prior to notification and subsequent permit modification, active mining limitations will apply regardless of actual mine status. 4. Compliance Schedules a. Twelve Time Analysis - OutfaB 015: The permittee shall complete a twelve time analysis as described in Pazt LB.3. Twelve monthly grab samples shall be collected at OutfaB 015 and analyzed with all results being submitted at the end of the sampling period. A sutrunary report in the form of a letter shall be submitted to the Permits Unit by September 30, of each year, documenting the progress in completing this sampling, until the 12 samples have been collected.. The pemilttee may attach the laboratory results if they choose. This report shall include all sample results collected over the twelve month period, from September to August. If sampling is incomplete, this shall be noted in the report. 5. Acute WET Testing - Outfa11015 a. Testing and Reporting Requirements Tests shall be done at the frequency listed in Part LB.1. Test results shall be reported along with the Discharge Monitoring Report (DMR) submitted for the reporting period during which the sample was taken. (i.e., WET testing results for the first calendar quarter ending March 31 shall be reported with [he DMR due April 28.) The results shall be submitted on the Acute 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 permittee shall conduct an acute 96-hour WET test using fathead minnows only. Acute tests will be replacement static tests of a single effluent grab sample. The permittee shall conduct each acute WET test in general accordance with AMENDED: JANUARY 25 2006 EFFECTIVE: MARCH 1, 2006 EXPIRES: MAY 31, 2009