2017-05-11_PERMIT FILE - C1981012 ‎(18)‎

• Permit No: C1981012
• IBM Index Class Name: Permit File
• Doc Date: 5/11/2017
• Section_Exhibit Name: Exhibit 22 NPDES Permit
• Media Type: D
• Archive: No

In TRIM
COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT, Water Quality Control Division
Fact Sheet- Page 24, Permit No. C00000906
Total / Total Recoverable Arsenic
For total recoverable arsenic, the analysis may be performed using a graphite furnace, however, this method
may produce erroneous results and may not be available to the permittee. Therefore, the total method of
analysis will be specified instead of the total recoverable method.
Total Mercury
To ensure adequate data are gathered to show compliance with the limitations, effluent monitoring for total
mercury at low-level detection methods will be required by the permit.
Dissolved Metals / Potentially Dissolved
For metals with aquatic life -based dissolved standards, effluent limits and monitoring requirements are
typically based upon the potentially dissolved method of analysis, as required under Regulation 31, Basic
Standards and Methodologies for Surface Water. Thus, effluent limits and/or monitoring requirements for
these metals will be prescribed as the "potentially dissolved" form.
TR Trivalent Chromium
For total recoverable trivalent chromium, the regulations indicate that standard applies to the total of both
the trivalent and hexavalent forms. Therefore, monitoring for total recoverable chromium will be required.
VIII. DISCUSSION OF STORMWATER-ONLY, NON -NUMERIC EFFLUENT LIMITATIONS, TERMS and CONDITIONS
This renewal permit contains requirements for stormwater discharges from the facility that are necessary to protect
waters of the State. Many of the stormwater provisions in the renewal permit are the same, or similar, to those in the
previous stormwater permit. New stormwater provisions resulted from a comprehensive review of stormwater
provisions for mining and non -mining sectors in existing CDPS permits, and coordination with the Division of
Reclamation, Mining and Safety (DRMS).
A. Narrative Water Quality Effluent Limitation (Outfalls 004, 007, 008, 010, 011 and 012)
This permit section contains the narrative effluent limitation that 'discharges authorized under this permit must be
controlled as necessary to meet applicable water quality standards.' This statement replaces the statement in the
previous permit that "stormwater discharges from mining operations or mine -waste remediation projects shall not
cause or threaten to cause pollution, contamination or degradation of State waters". Consistent with other
recently issued stormwater discharge permits, the division used the revised narrative WQBEL language as it more
directly relates stormwater discharge quality to water quality standards.
As provided in the permit, the division expects that compliance with the other conditions in the permit will control
discharges as necessary to meet applicable water quality standards, but requires the permittee to take corrective
action if the permittee becomes aware, or the division determines, that the authorized discharge causes or
contributes to an exceedance of applicable water quality standards. For such cases, the division also included a
provision in the permit that allows it to modify the permit to add site-specific terms and conditions as necessary to
control discharges to meet water quality standards.
B. Technology-based Effluent Limitations
1. Federal Effluent Limitation Guideline - Sediment Control Plan Outfalls 004, 011 and 012
The federal effluent limitation guideline applicable to outfalls 004, 011 and 012 is found under 40 CFR 434,
titled Coal Mining, Point Source Category, Alkaline Drainage, Coal Preparation Plants and Coal Preparation
Plant Associated Areas and Western Alkaline Coal Mining - Subpart H (40 CFR Part 434.82). This subpart applies
to alkaline mine drainage at western coal mining operations from reclamation areas, brushing and grubbing
areas, topsoil stockpiling areas, and regraded areas.
As provided by Subpart H, the following effluent limitations apply to mine drainage from applicable areas of
western coal mining operations:
a. The operator must submit a site-specific Sediment Control Plan to the permitting authority (Division of
Mining, Reclamation, and Safety) that is designed to prevent an increase in the average annual