REP50306

• Permit No: C1980007
• IBM Index Class Name: Report
• Doc Date: 8/25/1988
• Doc Name: MT GUNNISON 1 MINE SUBSIDENCE MONITORING C-80-007
• From: MRLD
• To: WEST ELK COAL CO
• Permit Index Doc Type: SUBSIDENCE REPORT
• Media Type: D
• Archive: No

iii iiiiiiiini~i iii
STATE OF COLORADO
Roy Romer, Gove
DEPARTMENT OF NATURAL RESOURCES
MINED LAND RECLAMATION DIVISION
FRED R. BANTA, Director
August 25, 1988
Mr. Dennis Conn
West Elk Coal Company
P,O. Box 591
Somerset, CO 81434
Re: Ftt. Gunnison No. 1 Mine
Subsidence M1tonitoring, C-80-007
Dear I•tr. Conn:
We have reviewed the subsidence monitoring results which you submitted on
April 11, 1988.
To date the monitoring results appear to verify WECC's original projections
contained within the permit application. The magnitudes of vertical
subsidence noted are less than predicted. Final results may warrant revision
of the original projection subsidence factor for purposes of future mine
planning.
The monuments located above the South Main Intakes appear to show
insignificant vertical movement, with one exception. Monument No. 15 appears
to have dropped 0.68 feet, which seems unlikely. It is possible that the
survey was in error or that some non-subsidence related factor is responsible
for the apparent movement, such as frost-heave, local slope movement, wildlife
interference, etc. WECC should investigate the possible causes of movement
experienced by Monument No. 15.
After completion of the 1988 surveys WECC should be able to draw some credible
conclusions regarding the character of ground subsidence above the
Ilt. Gunnison No. 1 mine underground workings.
If you have any questions please feel free to cal].
Sincerely,
o~.~.~, .'~ .
Susan J. Mo y
Reclamation Specialist
SJ M/ 1 j t
9769E
215 Centennial Building, 1313 Sherman Street Denver, Colorado 80203-2273 Tel. [phone]