Natural Events Action Plan

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Executive Summary

A number of Federal Reference or Equivalent PM10 monitors are located in Wyoming’s Powder River Basin (PRB) at several large mining operations.  Some of the monitors have recorded exceedances of the 24-hour National Ambient Air Quality Standard (NAAQS) for PM10 (particulate matter having a nominal aerodynamic equal to or less than 10 microns).  Each of the monitored exceedances was associated with high winds and blowing dust resulting from prolonged periods of low precipitation and consequential low soil moisture content. 

On May 30, 1996, the Environmental Protection Agency (EPA) issued a Natural Events Policy (NEP)1 which recognized that certain uncontrollable natural events, such as high winds, wildland fires, and volcanic/seismic activity can result in adverse consequences for the NAAQS.  The NEP set forth procedures for protecting public health through the development of a Natural Events Action Plan (NEAP) which implements Best Available Control Measures (BACM) for human-generated particulate emissions in areas where the PM10 standard may be violated due to these uncontrolled natural events.  The NEP also provides that if an approved NEAP is implemented, future air quality exceedances due to uncontrollable natural events may be flagged, and, if demonstrated to be a natural event, not be considered when determining the region’s air quality designation if BACM measures are being implemented.  The guiding principles of the policy are:

  1. Protection of public health is the highest priority of the Federal, State and local air pollution control agencies.
  2. The public must be informed whenever air quality in an area is unhealthy.
  3. All valid ambient air quality data should be submitted to the EPA Air Quality System (AQS) and made available for public access.
  4. Reasonable measures safeguarding public health must be taken regardless of the source of PM10 emissions.
  5. Emission controls should be applied to sources that contribute to exceedances of the PM10 NAAQS when those controls will result in fewer violations of the standards.

In response to the measured exceedances of the PM10 NAAQS as the result of dust generated by high winds and in anticipation of possible future exceedances, the Wyoming Department of Environmental Quality, Air Quality Division and stakeholders have developed this NEAP for the Powder River Basin of Wyoming. 

All coal mines in the Wyoming PRB employ Best Available Control Technology (BACT).  This Natural Events Action Plan for the Powder River Basin identifies BACT measures in place as the result of existing permit requirements, additional potential control measures identified as BACM, and reactionary control measures directed at transient problem sites that may be implemented during Natural Events.   Implementation of BACT, BACM, and reactionary control measures will assure that anthropogenic dust emissions from the coal mines in the PRB are controlled to the greatest extent possible.  The goal is to protect public health and to minimize exceedances of the PM10 NAAQS through the continued implementation of BACT, and implementation of BACM and reactionary control measures.

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1
Natural Events Policy (NEP) Memorandum. EPA, May 30, 1996.

Notices of Meetings, Minutes of Meetings, Handouts and Documents

Foundation Coal Company's Eagle Butte Mine requested exceedances of the 24-hour PM10 standard collected at their mine on June 29, 2007 be flagged as natural events under the Natural Events Action Plan (NEAP).  The Foundation Coal Company submitted a documentation packet to the Air Quality Division (AQD) in support of their request to flag these data.  The Air Quality Division will submit this documentation packet to EPA after a 30-day public comment period.  Public comments must be directed to Cara Keslar, Monitoring Section Supervisor, WDEQ-AQD, Herschler Building 2-E, 122 West 25th Street, Cheyenne, WY, 82002, and received no later than May 22, 2008.

Foundation Coal Company Eagle Butte Mine Documentation Packages
June 29, 2007 Eagle Butte Mine Exceedance Documentation Packages

  pdficons.gif (172 bytes)Request 1 of 2
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Request 2 of 2

Thunder Basin Coal Company's Black Thunder and North Rochelle Mines requested exceedances of the 24-hour PM10 standard collected at their mines on January 8 and 10, 2007 be flagged as natural events under the Natural Events Action Plan (NEAP).  The Powder River Coal Company submitted documentation packets to the Air Quality Division (AQD) in support of their request to flag these data.  The Air Quality Division submitted these documentation packets to EPA after a 30-day public comment period.  The public comment period is closed.

Thunder Basin Coal Company Black Thunder and North Rochelle Mines Documentation Package
January 8 and 10, 2007 Black Thunder and North Rochelle Mines Exceedance Documentation Package

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Powder River Coal Company's Rawhide Mine requested exceedances of the 24-hour PM10 standard collected at their mine on March 27, 2007 be flagged as natural events under the Natural Events Action Plan (NEAP).  Additionally, Buckskin Mining Company's Buckskin Mine requested exceedances of the 24-hour PM10 standard collected at their mine on March 27, 2007 be flagged as natural events under the NEAP.  Both mines submitted documentation packets to the Air Quality Division (AQD) in support of their request to flag these data.  The Air Quality Division submitted these documentation packets to EPA after a 30-day public comment period.  The public comment period is closed.

Powder River Coal Company Rawhide Mine Documentation Packages
March 27, 2007 Rawhide Mine Exceedance Documentation Packages and Accompanying Map

  pdficons.gif (172 bytes)Request 1 of 2
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Request 2 of 2
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Map

 

Buckskin Mining Company Buckskin Mine Documentation Packages
March 27, 2007 Buckskin Mine Exceedance Documentation Packages and Accompanying Map

  pdficons.gif (172 bytes)Request 1 of 2
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Request 2 of 2
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2006 Qtly Rpt 1
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2006 Qtly Rpt 2
 
pdficons.gif (172 bytes)2006 Qtly Rpt 3
 
pdficons.gif (172 bytes)2006 Qtly Rpt 4
 
pdficons.gif (172 bytes)2007 Qtly Rpt 1
 
pdficons.gif (172 bytes)Wind Speed Data
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Map


Powder River Coal Company's North Antelope Rochelle Mine requested exceedances of the 24-hour PM10 standard collected at their mine on January 8, 2007 and February 24, 2007 be flagged as natural events under the Natural Events Action Plan (NEAP).  Powder River Coal Company submitted documentation packets to the Air Quality Division (AQD) in support of their request to flag these data.  The Air Quality Division submitted these documentation packets to EPA after a 30-day public comment period.  The public comment period is closed.

North Antelope Rochelle Mine Documentation Packages
January 8, 2007 North Antelope Rochelle Mine Exceedance Documentation Package and Accompanying Map

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Map

February 24, 2007 North Antelope Rochelle Mine Exceedance Documentation Package and Accompanying Map

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Map

An Air Quality Advisory Board Meeting was held in Gillette on July 10-11, 2006.  The topic of discussion on July 11th was the Natural Events Action Plan (NEAP).  To view the NEAP PowerPoint presentation shown at the meeting, click here.
 

 Natural Events Action Plan Documents

1996 Natural Events Policy Memo pdficons.gif (172 bytes)
Natural Events Action Plan pdficons.gif (172 bytes)

NEAP PowerPoint Presentation

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