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West Elk Mine 2008 Annual Hydrology Report 45 <br />S lbs/day for BODs and 12 lbs/day for TSS. These limitations are based on a design flow of 0.02 <br />mgd and the concentration based, 30-day average limits of 30 mg/L and 75 mg/L for BODs and TSS, <br />respectively. The Division views these modifications as providing equivalent protection to the <br />percent removal requirements and therefore consistent with applicable, antidegradation and <br />antibacksliding requirements. Part LA.I.e. iii of the permit has been amended to reflect these <br />changes. " (CDPHE, 2009a) <br />4.4.2 Outfa11017A <br />During WY 2008, MCC reported a total of five exceedances at Outfall 017A (MCC, 2009; <br />CDPHE, 2008). MCC notified the WQCD of the exceedances during a meeting on August 21, <br />2008. MCC stopped discharging from Outfall 017A on July 17, 2008. The five permit <br />exceedances occurred at Outfall 017A during the third quarter of WY 2008, prior to cessation of <br />discharge at Outfall 017A. MCC is investigating potential remedies in the event of future <br />discharges at Outfal1 017A. <br />"A total of two samples were collected at Outfall 017A during the third quarter. The first sample was <br />collected on July 1, 2008 and exceeded the total suspended solids (TSS) and potentially dissolved iron <br />(Fe-PD) discharge limitations for Outfall 017A specified under Part I.A. c of the Permit. Laboratory <br />results from the second sample collected on July 9, 2008 indicate that the discharge limitations at <br />Outfall 017A were exceeded for TSS, Fe-PD and total recoverable iron (Fe-TR). Averaging the <br />results of these two samples for July indicates exceedances of the 30-day averages for TSS, Fe-PD, <br />and Fe-TR. The daily maximum limitation for TSS was also exceeded at Outfall 017A in the two <br />samples collected during the month of July 2008. <br />The reasons for these exceedances was determined to be insufficient residence time in the polishing <br />pond associated with Outfall 017A which did not allow the TSS to settle. It is likely that the Fe-PD <br />and Fe-TR were a component of the TSS and would have benefited by more time in the polishing <br />pond. Corrective and preventive measures have consisted of discontinuing the discharge at Outfall <br />017A until it is determined that the applicable discharge limitations can be achieved" (MCC, 2009, <br />CDPHE, 2008). <br />4.4.3 Bio-Monitoring Testing for Toxicity <br />During part of WY 2008, MCC conducted bio-monitoring tests as required by the CPDS permit <br />(MCC, 2009). Bio-monitoring sampling, including whole effluent toxicity or "WET" tests, were <br />conducted in the fourth quarter of 2007 and the first and second quarter of 2008 from the West <br />Fork of the Sylvester Gulch effluent discharge (Outfall 017A). No WET testing was conducted <br />during the third quarter of 2008, because samples were not collected prior to the cessation of <br />discharge on July 17, 2008 (MCC, 2009). On September 11, 2008 MCC requested a waiver from <br />the WQCD to waive the WET testing for the third quarter of 2008, since no further discharge was <br />anticipated during the remainder of the quarter. The waiver was granted and confirmed by email <br />and the letter dated October 24, 2008 (CDPHE, WQCD, 2008). The waiver letter states, "The <br />Division strongly suggests that Mountain Coal conducts WET sampling immediately upon <br />initiating discharge from Outfall 017A. " Static toxicity tests for acute (48-hour) and chronic (96 <br />hour) were completed in WY 2008. The test organisms included the daphnid (Daphnia magna) <br />and the fathead minnow (Pimephales promelas). The test results indicated that neither population <br />June 2009 HydroGeo, Inc.