APPCOR12443

• Permit No: C1996083
• IBM Index Class Name: Application Correspondence
• Doc Date: 5/31/1996
• Doc Name: BOWIE RESOURCES LIMITED BOWIE 2 MINE FN C-96-083 NEW PERMIT APPLICATION
• From: DMG
• To: J E STOVER & ASSOCIATES
• Media Type: D
• Archive: No

''
J.E. Stover & Associates -34- May 31, 1996
Bowie No. 2 Mine
1.6 ZONES OF POTENTIAL FRACTURING
The preparer states that
decrease as mining depth
except in the instances
discontinuity, such as a
significant differential
occur rapidly above such
the risk oP surface fracturing will
increases. This generally correct,
There mining encounters a significant
fault. As mentioned earlier,
offset and resultant fracturing can
a ground mass discontinuity.
The preparer relates the unusually large surface cracking
observed above the 1st West and 2nd West panels of the Bowie ,~1
mine. This area has been hypothesized to have undergone a
general cantilevered failure of the outcrop barrier and remnant
inter-panel pillars, due to a combination of weak oxidized coal
and an insufficient barrier pillar width. The implications of
this experience are significant for the near subcrop portions of
the Bowie No. 2 mine.
1.7 ZONES ALONG OUTCROP BARRIER PILLAR
The experience within the 1st West
Bowie ~1 mine suggest it is approp
delineation of an adequate outcrop
#2 mine. Further, observations by
cliffs region of Utah and Colorado
generally warranted.
and 2nd
riate to
barrier
Dunrud
suggest
West panels of the
be concerned about the
pillar for the Sowie
throughout the book
that the concern is
The preparer is ambiguous in this important section of Exhibit
15. It is first stated; "The 300 feet width of the outcrop
barrier pillar which is assumed for the future mine appears to be
conservative if most of the pillar is located in sound coal."
Next it is stated; "When, during development of the panels near
the outcrop, low quality coal is encountered, one row of
development pillars would be a sufficient outcrop barrier for the
Bowie #2 mine. This outcrop barrier 110 feet wide, should
prevent the potential crushing, sliding, or other failure near
the outcrop." If this statement is intended to commit to an
additional outcrop barrier width of 110 feet, resulting in an
outcrop barrier pillar 410 feet thick, the Division may concur.
91. The applicant should clarify this proposal. Further,
additional information should be provided to stipulate
whether the extended pillar will be unmined, or developed.
Obviously, at least one development room will have been
extracted in order to encounter the low quality coal. The
application should expand on this proposal to clarify the
approach to be implemented.
Chimney Collapse Prediction