2010-12-15_PERMIT FILE - C1980005A (5)

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PARTI Page No. 13 Permit No.: CO-0000221 2. Whole Effluent Toxicity -Chronic Lethality Limitation - Outfall WTE (Outfall 008) - Beginning immediately 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. Such limitation shall apply as a daily maximum. 3. 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 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 will need to show that exceedance of the applicable limitations was caused by precipitation (surface runoff water) and not mine water or spoils spring water, through a comparison of the loading from each source. Outfalls 009 and 015 are eligible for relief from TSS, total iron and SS on the basis that only surface runoff discharges are authorized from these outfalls. Relief may be granted for each discharge occurrence 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. 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 that 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 event has stopped. ® b. For post-mining outfalls: For rainfall, to waive settleable solids limitations, it 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 penmittee shall submit adequate proof in order for an exemption to be claimed. Weather station data may be 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. 4. Post-Minine 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 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 regardless of actual mine status. 5. Compliance Schedules No later than 14 calendar days following each date identified in the following schedules of compliance, the permittee shall submit either a report of progress or, in the case of specific actions being required by identified dates, a written notice of compliance or noncompliance, any remedial actions taken, and the probability of meeting the next scheduled requirement. a. Sediment Control Plan - In accordance with 40 CFR Part 434.82, the permittee must submit a site-specific Sediment Control Plan to the permitting authority that is designed to prevent an increase in the average annual sediment yield from pre-mined, undisturbed conditions, from the following areas: reclamation areas; brushing and grubbing areas; topsoil stockpiling areas and; regraded areas. For this facility, Outfalls 009A and 015A are required to have a Sediment Control Plan. The Sediment Control Plan must be approved by the permitting authority and be incorporated into the permit as an effluent limitation. The Sediment Control Plan must identify best management practices (BMPs) and also must describe