REV96947

• Permit No: C1980007
• IBM Index Class Name: Revision
• Doc Date: 6/14/1994
• Doc Name: WEST ELK MINE ADEQUACY REVIEW TR 69 LONE PINE GULCH VENTILATION FAN BENCH PN C-80-007
• From: DMG
• To: CHRISTINE JOHNSTON
• Type & Sequence: TR69
• Media Type: D
• Archive: No

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STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Depanmenl of Natural Resources
1313 Sherman 51., Room 215
Denver, Colorado 80207
Phone: [phone]
FAX: [phone]
DATE: June 14, 1994
TO: Christine Johnston
FROM: Jim Pendleton
RE: West Elk
Review, T.R. 69
"Lone Pine Gulch Ventilation Fan Bench..."
(Permit No: C-80-00'n
f~
DEPARTMENT OF
NATURAL
RESOURCES
Roy Ronser
~~r~r
dames s E«hncad
E aecuuve Direcm.
Michael B. Long
Division Dir«rnr
I have reviewed the T.R. 69 application submitted by Mountain Coal
Company. I have serious geotechnical concerns regarding this
application.
s~o~ st~na~cy
Fan Bench
The Mount Gunnison No. 1 mine surface facilities in the portal area
and Sylvester Gulch have been the repeated subject of landslide
disruption. The Mesa Verde Group and Williams Fork Formation are
notorious for their susceptibility to landsliding. Their situation
on the downdip slope renders many of Mt. Gunnison's facilities even
more susceptible to slope displacement. Any loading of these
slopes by material placement or facility construction or removal of
buttressing support by excavation can reduce the slope safety
factor below unity, resulting in slope movement. These potential
problems were identified by the Division during the review of the
original permit application. The operator was required to analyze
the situation and develop reclamation plans to overcome the
potential stability problems. In fact, the majority of the
operational retention structures are required to remain in place in
order to avoid failure of backfilled material.
Even with design precautions, the main F-Seam portals, the transfer
conveyors, the access and haul roads, the Sylvester Gulch access
road, the electric substation, are a few examples of specific
facilities which have been impacted by landsliding at the mine. In