REV96950

• Permit No: C1981019
• IBM Index Class Name: Revision
• Doc Date: 3/4/1996
• Doc Name: COLOWYO COAL MINE C-81-019 TR-36 AUGER MINING AREA #2
• From: DMG
• To: COLOWYO COAL CO LP
• Type & Sequence: TR36
• Media Type: D
• Archive: No

111 Illllllllllll Ill
999
STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Dcpartmem of NNural Re,ourccs
1 31 S Sherman SL, Room ? 15
Denver, Colorado NO?0]
Phone: [phone]
FA%:1}031 BILK 106
March 4, 1996
Mr. Jim Kiger
Colowyo Coal Co. L.P.
5731 State Highway 13
Meeker, CO 81641
RE: Colowyo Coal Mine (C-81-019)
TR-36; Auger Mining Area #2
Deaz Mr. Kiger,
~I~~~
DEPARTMENT OF
NATURAL
RESOURCES
Roy Romer
Governor
lames 5 Lochhead
Executive Dueaor
Michael B. Long
Dlviuon DveUnr
The Division of Minerals and Geology received your technical revision application (TR-36)
to add Auger Area #2 to the Colowyo mine plan. The proposed auger mining will occur
within the X Seam along the north and east end walls of the West Pit. In the future, auger
mining may be conducted in either the C Seam or D Seam. This would be the subject of
a future revision application. Jim Pendleton of our office reviewed the revision and has the
following comments that need to be addressed prior to approval of the revision;
Streeter Pit and Stability Evaluation, North Wall of West Pit..."
In conjunction with the technical revision application, the Division reviewed the
"Geotechnical Investigation of the West Pit Excess Spoil Disposal Site...", and the
CONFIDENTIAL CTL/Thompson report entitled, "Auger Mining Analysis, West Pit and
Subsidence Concern
The plan appears straight forward. No structures appear to be at risk, if unexpected
subsidence were to occur, other than the West Pit Disposal Pile. If subsidence were to
occur through the approximately 250 feet of bac)dill and bedrock, the Division suspects that
minor cracking and deflation would be the only surface expression. These impacts could be
mitigated by regrading and repair. CTL/Thompson projects that the magnitude of any
subsidence should be small in relation to normal consolidation of the fill thickness. Because
the augered area will underlie the West Pit Fill it would be difficult to distinguish between
subsidence due to collapse and subsidence due to normal consolidation.