REV90872

• Permit No: C1996083
• IBM Index Class Name: Revision
• Doc Date: 10/17/1997
• Doc Name: BOWIE 2 MINE MR04 PORTAL CUT LANDSLIDE REPAIR PN C-96-083
• From: DMG
• To: JOE DUDASH
• Type & Sequence: MR4
• Media Type: D
• Archive: No

• • iii iiiiiiiiniiiiii~
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STATE OF COLORP~UU
DIVISION OF MINERALS AND GEOLOGY
Depanment of Natural Rewurces
1713 Sherman 51., Roam 215
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
DATE: October 17, 1997
TO: Joe Dudash
FROM: Jim Pendleton
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RE: Bowie Mine - .R. 04 -Portal Cut Landslide Repair
(Perini : C-96-083)
I have reviewed the supplemental responses submitted by Bowie Resources Limited (BRL),
which you forwazded to my attention. These submittals respond to your eazlier incompleteness
letter regazding BRL's original submittal of M.R. 04.
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DEPAIiTMEfJT OF
NATURAL .
RESOURCES
Roy Romer
Governor
fames 5. Lochhead
Execwive Director
Michael B Long
Division Dlrecror
BRL has subritted a stability analysis prepazed by MAXIM, Inc., geotechnica] consultant.
MAXIM's analysis is based upon material strength parameters reviewed and accepted by the
Division as a portion of the original permit application. They do appear appropriate for this
analysis. The analysis projects that the final configuration, including a backfilled upper cutslope
at 1.75h: l v, and a backfilled lower slope (above the multi plate tubes) of 2h:1 v, will have a static
slope safety factor of between 1.5 and 1.8 I recommend acceptance of MAXIM's analysis and
approval of the modified plan.
The failure, as J.E. Stover and Associates postulates, probably occurred because BRL had grossly
over steepened the portal bench cutslope while driving the initial portal entries. Hopefully, BRL
will succeed in completing [he three portal face up, installation of the multi plate tubes, and
backfilling above the tubes to the approved configuration.
I believe it would be appropriate to require BRL to monitor the success of its repair, as a
condition of approval of M.R. 04. I recommend that BRL be directed to install two
perpendicular ("X") lines of metal fence posts on the backfilled slope to allow visual monitoring
of the stability of the final configuration. This should also provide visual warning to the
operational personnel entering the portals.
In consideration of MAXIM, Inc.'s demonstration, 1 do not believe your proposed DRAFT'
stipulation to be necessary as a portion of the Division's approval of M.R. 04.
cc:
Dave Berry
doc: M:\CoaIUAP\BRLMR04.WPD