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Kentucky DEP Issues Guidance Document on KPDES Coal General Permit


The Kentucky Department for Environmental Protection recently issued a guidance document responding to the coal industry’s frequently asked questions about the currently-effective KPDES Coal General Permit.  The document, entitled “Frequently Asked Questions About the KPDES Coal General Permit Issued on August 1, 2009,” (FAQ Document) is available on the Division of Water’s website at:

Discharges of wastewater from many surface and underground coal mining operations in Kentucky are authorized pursuant to the Coal General Permit.  But many of the detailed requirements for complying with the Coal General Permit are not specifically addressed in the permit itself, and at times the coal industry has received inconsistent guidance from the various divisions of the Energy and Environment Cabinet (Cabinet) regarding the requirements of the General Permit.  The Cabinet’s new FAQ Document is designed to address many of these concerns.

Among the most important and frequently arising issues addressed by the FAQ Document are: when alternate effluent limitations are applicable due to precipitation events, how permittees should address and report “no flow” events, and how changes in the mining and reclamation phase of an operation change the applicable effluent limitations in the permit.  Other issues associated with the Coal General Permit are also addressed in the FAQ Document, and coal mine operators should consult the full document in conjunction with their discharge monitoring and reporting efforts.

Alternate Precipitation Effluent Limits

In certain cases, the Coal General Permit provides for alternative (and less stringent) effluent limits if the discharge is sampled during a qualifying precipitation event.  Determining when these alternate effluent limits apply, and properly documenting a claim of alternate effluent limits, has been a source of considerable uncertainty for industry.  The FAQ Document addresses what types of precipitation events trigger the application of alternate effluent limits, and the types of discharges to which alternate limits may be applied.  The FAQ document also clarifies that the amount of precipitation qualifying as a precipitation event for purposes of alternative effluent limits is contained in a Cabinet memorandum, Rainfall Frequency Values for Kentucky, Engineering Memorandum No. 2, available at

According to the FAQ Document, in order to claim alternate precipitation effluent limits, the permittee must submit a request form, available at, along with required supporting documentation.  This documentation includes:

  • Precipitation data from an on-site precipitation gauge or other source within a five-mile radius that can be corroborated with NOAA or other official precipitation data;
  • The date and time of the sample (the sample must be taken within 24 hours of the precipitation event);
  • The type(s) of discharge(s) associated with the outfall’s drainage area; and
  • Sample results.

This supporting documentation must be submitted electronically with the Discharge Monitoring Report (DMR).  Providing the required supporting documentation for claiming alternate effluent limits is important, because the FAQ Document clarifies that the permittee has the burden of proving that an alternate effluent limit is appropriate.

The FAQ Document also clarifies how DEP will process claims for alternative effluent limits.  Specifically, DEP will not immediately notify a permittee of whether a request for an alternate limit has been approved.  Instead, the request is considered “conditionally approved” until such time as DEP reviews the DMR and supporting documentation and determines that approval should not be granted.

No Discharge Events

Another frequently-arising issue addressed by the FAQ Document is the “no flow” or “no discharge” event.  In many instances, the point source discharges associated with mining activity and regulated by the Coal General Permit are on-bench drainage/sediment ponds that rarely discharge, or discharge only after significant precipitation events.  DEP and industry have struggled with how to properly document these “no flow” events on DMRs.  According to the FAQ Document, where there was only one or no discharge from an outfall during a monitoring period, the permittee must submit with the DMR:

  • A statement certifying that the ponds were constructed, maintained and operated in accordance with performance standards approved by the Department for Natural Resources, and
  • Daily precipitation information for the month indicating that no storm event exceeded the 10-year, 24-hour precipitation event for the area during the monitoring period.

The permittee should also continue to check the “no discharge” box on the DMR if there was no discharge during the reporting period (but this box should not be checked if there was only one discharge).

Changes in Mining Phase

The FAQ Document also clarifies that for surface mines the sampling requirements under the Coal General Permit change upon a mine obtaining “Phase I” bond release under its surface mining permit.  Phase I bond release is obtained when backfilling and grading have been sufficiently completed to return a mining area to its approximate original contour.  By contrast, for underground mining, sampling requirements do not change until receipt of Phase III bond release.  Phase III bond release is obtained when all reclamation requirements on a permitted area are complete.  Regardless of mining phase, pH must still be sampled twice per month.  The only significant change related to mining phase is that upon change from active to post-mining status (i.e. Phase I for surface areas and Phase III for underground mines), settleable solids requirements are substituted for total suspended solids, and iron and manganese are not required to be reported.  All other effluent limits remain the same.  The mining phase for a particular permitted area is determined by reference to information from the Department for Natural Resources (DNR).  DNR should be contacted to verify that a mine has been granted Phase I, II, or III bond release prior to assuming that a change in mining phase has occurred.

As a guidance document, the FAQ Document is not given the force and effect of a binding regulation.  It is expected, however, that the Cabinet will consider a permittee’s compliance with the guidelines in the FAQ Document in discussions with the agency regarding enforcement actions.

To view a complete PDF of the January/February 2013 issue of the Environmental Letter, click HERE.

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