2009-04-29_REPORT - C1980007

• Permit No: C1980007
• IBM Index Class Name: REPORT
• Doc Date: 4/29/2009
• Doc Name: 4th Quarter 2008 Seismic Monitoring Report Review
• From: Tom Kaldenbach
• To: File
• Permit Index Doc Type: Stability Report
• Email Name: TAK
• Media Type: D
• Archive: No

STATE OF COLORADO
DIVISION OF RECLAMATION, MINING AND SAFETY
Department of Natural Resources
1313 Sherman St., Room 215
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
MEMO
COLORADO
DIVISION OF
RECLAMATION
MINING
SAFETY
From: Tom Kaldenbach Bill Ritter, Jr.
Governor
Harris D. Sherman
To: File Executive Director
• West Elk Mine (C-1980-007) Ronald W. Cattany
Report Division Director
Seismic Monitoring Report for 4th Quarter 2008 Natural Resource Trustee
Date: April 29, 2009
Re: Summary of DRMS Review
MCC's Subsidence Monitoring Plan requires monitoring of seismicity for identifying the
magnitude of seismic events at Monument Dam (Sections 2.05.6(6(b)(ii), (6)(c(ii), and
(6)(e)(iii) of the permit application). MCC began longwall mining in the E seam in the
4th quarter of 2008. MCC is required to make field measurements of monuments on the
dam within two days of any mining-caused seismic event that exceeds peak ground
acceleration of 0.15 g at the dam (permit application page 2.05-168). An accelerometer
at the dam continuously monitors seismic activity. Data from the Monument Dam
accelerometer and nine other accelerometers installed at the West Elk Mine and Bowie 11
Mine enable determination of the geographic location and depth of each seismic event.
The above-referenced reports indicates the peak ground accelerations at the dam during
the 4th quarter of 2008 did not exceed the 0.15 g threshold.
cc: Dan Hernandez, DRMS
Kathy Welt, DRMS
Office of Office of
Mined Land Reclamation Denver • Grand Junction • Durango Active and Inactive Mines