2009-06-15_REVISION - C1996083 ‎(4)‎

• Permit No: C1996083
• IBM Index Class Name: REVISION
• Doc Date: 6/15/2009
• Doc Name: Adequacy Review
• From: J.E. Stover & Associates, Inc
• To: DRMS
• Type & Sequence: TR61
• Email Name: JJD
• Media Type: D
• Archive: No

J. E. STOVER & ASSOCIATES, INC.
P.O. BOX 60340
GRAND JUNCTION, COLORADO 81506
PHONE: [phone], FAX [phone]
MINE ENGINEERING CIVIL ENGINEERING
MINE RECLAMATION CONST. MANAGEMENT
June 11, 2009 JUN 15 2009
J. J. Dudash Dive,,,. . -nation,
Division of Reclamation, Mining & Safety Mining and Safety
1313 Sherman St., Room 215
Denver, CO 80203
RE: Bowie No. 2 Mine, Permit No. C-96-083, Bowie Resources LLC
Technical Revision No. 64, Coal Refuse Pile Slope Inclination, Adequacy Review
Dear Mr. Dudash:
The DRMS' letter dated June 1, 2009, transmitted its adequacy comments regarding the
referenced technical revision. Following are Bowie Resources responses to the DRMS'
comments and concerns:
DRMS:
Geotechnical Review
The application for TR-61 was prepared to update the permit application package to reflect a
steepened slope configuration for Coal Mine Waste Disposal Area #2 (CMWDA2) that was
previously approved under TR-56. With TR-56, the operator successfully demonstrated [in a
report prepared by Buckhom Geotech, Inc. (BG1)] that slopes as steep as 3H: 1 V for the upper
portions of CMWDA2 will provide a Factor of Safety of 1.50 when proper methods of
construction are used and site conditions are periodically monitored.
In its review for TR-56, the Division listed several items that the upcoming technical revision
application (TR-61) would be expected to address. Those items are each repeated below ("OC",
for "Original Comment"), followed by an evaluation of the current TR-61 application ("NC", for
"New Comment").
Vibrating Wire Piezometers
OC: Five instruments were originally installed in four separate holes in 2005; two of the
piezometers (in two holes) later ceased to function. Pore pressure data from the remaining three
piezometers were utilized to develop assumptions for use in the stability evaluation. In Section
6.0 (Page 14 of 15), BGI recommends on-going monitoring of piezometers as construction of
CMWDA2 progresses.
Please describe the proposed on-going piezometric monitoring plan, including the locatipns of
any new piezometers to be placed, any anticipated modification of existing piezometers, and the
proposed monitoring frequency.
NC: Page 14 of the Volume IX text in the application states, in essence, that quarterly inspection
reports will provide a summary of instrumentation monitoring on CMWDA2, including a
discussion of the vibrating wire piezometer data. This data will determine if the measured pore
pressures are relatively stable, and consistent with those incorporated into the TR-56 BGI