2010-01-07_REVISION - C1996083

• Permit No: C1996083
• IBM Index Class Name: REVISION
• Doc Date: 1/7/2010
• Doc Name: Review Memo
• From: Kent Gorham
• To: Joe Dudash
• Type & Sequence: TR65
• Email Name: JJD
• Media Type: D
• Archive: No

STATE OF COLORADO
DIVISION OF RECLAMATION, MINING AND SAFETY
Department of Natural Resources
1313 Sherman St., Room 215
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
COLORADO
D I V t S t O N O F
RECLAMATION
MINING
SAFETY
Bill Ritter, Ir.
Governor
Harris D. Sherman
Interoffice Memorandum Executive Director
Ronald W. Cattany
Division Director
To: Joe Dudash Natural Resource Trustee
From: Kent Gorha KO
CC: Sandy Brown
Subject: TR-65, Amend Mine Plan, Bowie No. 2, C-96-083
Date: January 7, 2010
As requested in your memo dated December 9, 2009, I have reviewed the revised materials for
Technical Revision No. 65 (TR-65) submitted by Bowie Resources. As per your instructions, I
reviewed the materials specific to the Rules and issues associated with subsidence. My
comments are found below.
The operator has provided the information for Rule 2.05.6(6)(b) [worst possible consequences]
for Terror Creek and the WAPA power line that parallels Terror Creek. They have also
included information required by Rule 2.05.6(6)(b)(iii)(B) [a subsidence control plan].
Rule 2.05.6(6)(f) [subsidence control plan] compliance is in part demonstrated by information
included in Exhibit 16, Overburden Stability at the Terror Creek Crossing. The operator will
prevent subsidence and any material damage caused from subsidence by using limited extraction
and mine development techniques that will prevent mine subsidence in the limited extraction
zone that includes Terror Creek and the WAPA power transmission line. Monitoring of both
Terror Creek and the WAPA power transmission line is proposed as required by Rule
2.05.6(6)(f)(iii)(C) to detect any subsidence should it occur, or in this case, to prove no
subsidence has occurred.
Exhibit 16, Overburden Stability at the Terror Creek Crossing also demonstrates compliance
with Rule 4.20.4 [Buffer Zones] which prohibits underground mining activities beneath or
adjacent to a perennial stream unless the Division determines, based on detailed subsurface
information, that subsidence will not cause material damage to the stream. Based on the
proposed entry development, the workings will have a safety factor ranging from 1.6 to 2.5.
Given that the undermining at the Terror Creek crossing is main development for the movement
of men and materials, prevention of subsidence is of obvious importance to the operator.
My final comment is related to the requirements of Rule 4.20.2 [Public Notice of the mining
schedule]. Although it appears that the operator has notified the owner of WAPA and provided
Office of
Office of Active and Inactive Mines
Mined Land Reclamation Denver • Grand Junction • Durango