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6/10/2013 14:0914:09 Jones, Dennis D. From: Jones, Dennis D. Sent: Friday, May 03, 2013 15:30 To: 'Morgan - CDPHE, Kelly' Subject: cdps co- 0048275 potential noncompliance issue at outfall 003 Attachments: npdes3 041913.pdf Kelly, I first reviewed today (5/3) data from ACZ Labs, with results for our 4/19/13 sample at Outfall 003 for the Peabody Sage Creek Mine (PSCM), CO- 0048275. The lab data indicates that we may potentially be out of compliance of our DMR limit for potentially dissolved (PD) selenium (Se), 4.6 ug /I. The lab data indicates a value of 4.9 ug /I for PD Se. The total recoverable (TR) Se value is also 4.9 ug /I. Therefore, we do not suspect any matrix interferences with this particular sample. The lab data is attached to this email. The Se limit stated both on the DMR and the discharge permit (issued 3/31/10) is 4.6 ug /I. However, The Reasonable Potential (RP) analysis performed for this permit (in the Rationale dated 2/4/10 by Andrew Nuehart) indicates that Se should be 'monitored' only. Therefore, I feel that the limit set in the permit is incorrect. I have included (in the attachment) that page of the Rationale, and the permit page indicating the limits. This inconsistency between the Rationale and the permit was just discovered by me today. Furthermore, this is the first excursion of the 4.6 ug /I Se standard since monitoring began at this outfall in 1980. The highest previous values were 4.0 ug /I TR on 6/10/96 and 3.1 ug /I PD on 3/9/11. Footnote 4 to Table III ( Metal Parameters) in the Colorado WQCC Regulation 31, ( first referenced in 7`h paragraph of Section 31.22 E (as Footnote 5 in an older version)), states: "Both acute and chronic numbers adopted as stream standards are levels not to be exceeded more than once every three years on average. " The flexibility for determining compliance of the stream standards for Se is not reflected in the Se effluent limits that were established for Outfall 003. One effluent limit exceedance in 33 years at this outfall is below the expected exceedance frequency adopted for metal standards. We have not determined the cause of the excursion, however, the facility and outfall are being properly operated and maintained. This possible exceedance occurred during spring snowmelt and runoff, similar to the conditions that occurred during the alleged prior selenium exceedances. Due to these climatic and hydrologic factors, the high selenium levels may be contributed by other sources. As you know part of sampling activities is to identify and quantify such sources. In addition, we did get about 2 inches (melted water equivalent) of late, heavy snow in April prior to the sampling event. I talked to Kelly Morgan with the WQCD about this at 10:05 AM today. PSCM considers these to be our CDPS permit required 24 hour notification. The permit requires that we also submit within 5 days a written report. If this email does NOT fulfill that requirement, please let me know, and I will follow up with a mail letter. Thank you, Dennis Jones Hydrologist - Seneca Coal Co. 970 - 276 -5209 d-iones(@peabodyenergy.com