2013-07-30_HYDROLOGY - C1982057

• Permit No: C1982057
• IBM Index Class Name: HYDROLOGY
• Doc Date: 7/30/2013
• Doc Name: 2nd Quarter 2013 DMRS
• From: Seneca Coal Company
• To: WQCD
• Permit Index Doc Type: DMR’s
• Email Name: JDM
• Email Name: SB1
• Media Type: D
• Archive: No

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Coal Company Seneca Coal Company
July 24, 2013
Colorado Department of Health
WQCD -PE -B2
4300 Cherry Creek Drive South
Denver, CO 80246 -1530
RECEIVED
JUL 3 0 2013
Division Qf Reclamation,
Muting
RE: Quarterly Discharge Monitoring Report for Seneca Coal Company, Permit CO- 0000221
Dear Sir or Madam:
Pursuant to the quarterly reporting requirements contained in Colorado Discharge Permit CO- 0000221 for
the Seneca Mine Complex, enclosed find the second quarter 2013 discharge monitoring reports for
Outfalls 005, 006 and 008 to 017. In this quarter, intermittent discharges were observed at Outfalls 005,
011, 013 and 014. No flows were observed at Outfall 009. All other Outfalls discharged continuously.
Three excursions of DMR limits occurred this quarter. The first involved the total recoverable iron value
of a sample from Outfall 011 taken on April 29. The second involved the total recoverable iron value of a
sample from Outfall 016 taken on April 30. The third involved the pH value of a sample from Outfall 013
taken on May 2. Attached to this cover letter are emails which discuss the details of each excursion. These
emails also served as our five day notice to the WQCD. Also attached are lab data referenced in the
emails.
In addition to these excursions, one selenium (Se) value reported by Seneca's lab (ACZ Labs in
Steamboat Springs, CO) was not reported on the DMR. This occurred on a sample collected at Outfall 008
on June 10, 2013. Additional analyses for selenium were performed by the lab as described below.
The original potentially dissolved (PD) by ICP -MS selenium analysis was performed on June 13, and
yielded a value of 7.1 ug/L. The lab also performed a total recoverable (TR) selenium analysis on the
same sample on June 12 that resulted in a value of 1.4 ug/L. Suspecting that water matrix interference
caused the high PD selenium value compared to the TR selenium value, the lab performed an additional
digestion on the PD sample on June 21 to remove the water matrix interference. The result of the June 21
analysis on the PD selenium sample was 1.2 ug/L.
The value reported on this DMR for Outfall 008 was 6.6 ug/L, which was the highest of the three reliable
monthly PD Se ICP -MS values for this quarter (6.1, 6.6 and 1.2 ug/L, respectively). Seneca believes the
7.1 ug/L value noted above to be a false high value, based on the total recoverable Se analyses performed
on that sample. 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 7.1 ug/L 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. An additional
TR digestion apparently removes that interference.
Seneca Coal Company • P.O. Box 670 • Hayden, Colorado 81639
Telephone [phone] • FAX [phone]