2012-08-30_HYDROLOGY - C2009087 (2)

Home Browse Search

Peabod 1111 ENERGY Peabody Sage Creek Mining, LLC Colorado Department of Public Health and Environment Water Quality Control Division Permits and Enforcement Section 4300 Cherry Creek Drive South Denver, CO 80246 -1530 Dear Sir or Madam: July 25, 2012 36600 Routt County Rd. 27 PO Box 250 Hayden, CO. 81639 (970) 276-7001 RECEIVED AUG 3 0 2012 Division of Reclamation Mining & Safety RE: Quarterly DMRs for CPDS Permit No. CO- 0048275, Peabody Sage Creek Mine Pursuant to the quarterly reporting requirements contained in Colorado Discharge Permit CO- 0048275 for the Peabody Sage Creek Mine, enclosed find the second quarter 2012 discharge monitoring reports for Outfalls 002 to 004. Two excursions of effluent limits occurred this quarter, both of which involved the selenium standard, 4.6 ug /1. The Outfall 002 potentially dissolved selenium value was 4.7 ug /1 on a sample collected June 6. This value was obtained by ICP -MS, EPA Method M200.8. However, one other selenium test method was performed on this sample, as we are investigating the differences in the methods. The total recoverable selenium value was 3.4 ug /1 on the same sample; this value was obtained by ICP -MS, EPA Method M200.8. As one would expect the total recoverable method to result in the same, or higher, value than the potentially dissolved method (the former involves a hot acid digestion, while the later involves a cold acid digestion), we suspect that the 4.7 ug /1 value to be in error. This may be due to matrix interference in the sample that displays itself in the potentially dissolved ICP -MS method. We have noticed this phenomenon in previous DMRs. The lab report for this sample is attached to this cover letter. Note that the lab report gives selenium values in mg /1, not ug /1. The Outfall 004 potentially dissolved selenium value was 5.7 ug /1 on a sample collected June 11. This value was obtained by ICP -MS, EPA Method M200.8. One other selenium test methods was performed on this sample also. The total recoverable selenium value was 1.3 ug /1 on the same sample; this value was obtained by ICP -MS, EPA Method M200.8. As one would expect the total recoverable method to result in the same, or higher, value than the potentially dissolved method (the former involves a hot acid digestion, while the later involves a cold acid digestion), we suspect that the 5.7 ug/1 value to be in error. This may be due to matrix interference in the sample that displays itself in the potentially dissolved ICP -MS method. The lab report for this sample is attached to this cover letter. Note that this lab report gives selenium values in ug /1.