2011-01-27_REPORT - C1980007 ‎(2)‎

• Permit No: C1980007
• IBM Index Class Name: REPORT
• Doc Date: 1/27/2011
• Doc Name: Spring 2010 Subsidnece and Geologic Observation
• From: DRMS
• To: Mountain Coal Company
• Permit Index Doc Type: Subsidence 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 C O L O R A D O
Denver, Colorado 80203 D IV IS I ON OF
Phone: [phone] RECLAMATION
FAX: [phone] MINING

January 27, 2011 SAFETY
John W.
ove oHickenlooper
Kathy Welt G
Mountain Coal Company, LLC
Mike King
P.O. Box 591 Executive Director
Somerset, CO 81434 Loretta E. Pineda
Director
Re: West Elk Mine
Report titled "Spring 2010 Subsidence and Geologic Observations"
Dear Ms. Welt:
We have the following comment regarding your memorandum of January 25, 2011 in which you
responded to our adequacy review letter of January 21, 2010.
As shown in attached Figure 1, the vertical distance to be used in calculating an angle of draw should
be the difference in elevation between the land surface at a station located at the limit of detectable
subsidence on the ground surface and the elevation of the top of the coal seam at the edge of the
workings. The table below shows the calculated angle of draw, using this method for quantifying the
vertical distance. Please revise Table 1 of Appendix B in the above-referenced report using this
method for quantifying vertical distance.
Monument Grid Ground Top of E seam at Vertical Horizontal Angle of
Used elevation at edge of Distance Distance Draw
Station, feet workings, feet (feet) (feet) (degrees)
(Appendix B (Map 17 in
of subsidence permit)
report)
Station 10 8009 6870 1139 340 16.6
Station 37 8080 6790 1290 340 14.8
Station 57 8108 6911 1197 290 13.6
Station 80 8035 6870 1165 290 14.0
Station 101 7950 6805 1145 380 18.4
Sincerely,
% -, /-C.
Tom Kaldenbach
Environmental Protection Specialist
cc: Dan Hernandez, DBMS
Office of Office of
Mined Land Reclamation Denver • Grand Junction • Durango Active and Inactive Mines