2008-11-24_PERMIT FILE - C1996083 ‎(6)‎

• Permit No: C1996083
• IBM Index Class Name: Permit File
• Doc Date: 11/24/2008
• Doc Name: 1st Quarter 2008 North Fork Valley Seismic Network Monitoring Report
• Section_Exhibit Name: Volume III Exhibit 18 Seismic Monitoring at BR Longwall Coal Mine
• Email Name: JJD
• Media Type: D
• Archive: No

TABLE OF CONTENTS
North Fork Valley Seismic Network - First Quarter 2008 ..........................................................................1
Summary ...................................................................... ........................................................1
Introduction .................................................................. ........................................................ I
Network Operations ..................................................... ........................................................1
Data Processing ............................................................ ........................................................2
Identification of Events .................................... ........................................................2
Location Methodology ..................................... ........................................................3
Magnitude Estimation ...................................... ........................................................4
Results .......................................................................... ........................................................4
Mining Progress ............................................... ........................................................4
Seismic Event Locations .................................. ........................................................4
Seismic Event Magnitudes ........... .................... ..........._............................................4
Recorded Peak Ground Accelerations ............. ........................................................5
Acknowledgments ........................................................ ........................................................5
References .................................................................... ........_...............................................6
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Tables
1 Seismograph Stations of the North Fork Valley Seismic Network
2 Velocity Model Used in Locating Seismic Events
3 Event Locations and Maximum Recorded PGAs
Figures
1 Seismic Station Locations, Permit Areas, and Mine Location Map
2 Relocated Seismicity, 1 January to 31 March 2008
3 PGA Values for Q1 2008 Shown With McGarr and Fletcher (2005) Attenuation
Relationship
UM W:\x_wds\PROJECTS\North Fork-Bowie\Quarterly reports\2008 Q1\Q1_2008_BRL_fina1.doc\0AK i