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PART I Page 5 Permit No. CO-0044776 A. DEFINTI'LON OF EFFLUENT LINIITATIONS 4. Burden of Proof Requirements The pertnittee has the burden of proof when requesting relief from total suspended solids (TSS), total iron and/or settleable so]ids limitations, as appropriate. The permittee should endeavor to meet [he primary limitations whenever possible. Relief is not available for mine drainage alone, nor when the majority of a dischazge consists thine drainage. Eor rainfall, to waive TSS and total iron limitations, it is necessary to demonstrate that dischazge occurred within 48 hours afrer measurable precipitation has stopped. To waive settleable solids limitations, it is necessary to prove tha[ discharge occurred within 48 hours after precipitation greater than the 10-yeaz, 24-hour event has stopped. For snowmelt, to waive TSS and total iron limitations, it is necessary to demonstrate that discharge occurred within 48 hours after pond inflow has stopped. To waive settleable solids limitations, it is necessary to prove that discharge occurred within 48 hours after pond inflow volume greater than the 10-yeaz, 24-hour event 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 should be submitted where appropriate. Documentation that the treatment facilities were properly operated and maintained prior to and during the storm event must be submitted with any request for relief. Additionally. for outfall 002. the netatittee must demonstrate chat Le maiorirv of the dischara,& for which Le ezemp ion is cl imed conci tc of urfa mnoff 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, whether proper sediment storage leve]s were maintained and the ponds had sufficient water and sediment capacity for the storm event plus other relevant factors. All manual pond dewatering must meet TSS and total iron limitations unless previous approval has been granted for ponds that have ~ other method of dewatering. For ponds with automatic dewacering structures,. only dischazges through these structures are eligible for the exemption. 5. Poct-Mining reac In conformance with 40 CFR 434.50, commencing at the time active mining has ceased and all surface azeas served by a sedimentation pond have been returned to the required contour and revegetation has commenced, applicable dischazges may be eligible for limitations other than those specified in Part I.A.1. In most cases, these post-mining limitations shall remain in effect until bond release. The permittee 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 regazdless of actual mine status. 6. Whole Effluent Toricity a 'ng_~eglrirementc (Acut 1 - Outf 11 002 a. Testing and Reporting Reaitirements WET testing shall be required whenever the discharge contains any flow from mine drainage and/or spoils spring sources. WET testing is not required when a dischage consists entirely of surface runoff. If discharge from outfall 002 contains mine drainage at anv time during the appropriate monitoring frequency period, WET testing is required during that period. Tests shall be done at the frequency listed in Part I.B.1. Test resulzs 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 calendaz quar[er ending March 31 shall be reported with the DMR due April 28.) The results shall be submitted on the Acute Tociciry Test report form. available =_ from the Division. Copies of these reports aze [o be submitted to both the Division and EPA along with the - DMR. t ;~- Amendment.No. 1 Issued ~ NAT (lam Effective ~t~' ` ~ -