REV01294

• Permit No: C1981019
• IBM Index Class Name: Revision
• Doc Date: 7/26/2002
• Doc Name: Adequacy Review
• From: DMG
• To: Colowyo Coal Company
• Type & Sequence: TR56
• Media Type: D
• Archive: No

STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Department of Natural Resources -
1313ShermanSL,Room215

Denver, Colorado 80203 DtvtSlON OF
Phone: [phone]~1 1 N 1 RA L $
FAX: [phone] &
GEOLOGY

Jllly 26,2002 RECLAMATION
MINING•SAFETY
C
Crellin Scott Bill Owens
. Governor
Senior Environmental Engineer Greg E. Walther
COlOWyO Coal COmpany L.P. Executive Direttor
5731 State Highway 13 Ronald W. Cattany
Meeker, CO 81641 Acting Division Director
Subject: Technical Adequacy 2, Technical Revision 56, Permit C-81-019
Reference: Colowyo Coal Company, L.P. (Colowyo) letter of June 26, 2002, Subject: Response
to Technical Adequacy letter dated March 15, 2002, Technical Revision 56, Permit C-81-019
Deaz Mr. Scott:
Thank you for your subject response, and for attending a meeting at the offices of the Division of
Minerals and Geology (Division) on July 24, 2002, to address and consider technical adequacy
concerns of the proposed revision.
The Division has concluded that Colowyo Coal Company, L.P. (Colowyo) proposed adjustments
to the currently approved Post Mining Topography in the vicinity of the north end of the West
Pit (Section 4, Map 19 proposed), considering the current states of reclamation and bond release
on the West Pit Excess Spoil Fill, are appropriate.
Item 1. A residual concern is that, in the south end of the West Pit, the north aspect of the West
Pit Ditch, and to a lesser extent, the grade of the West Pit Ditch thalweg, appear to pose
problems. The concern of steep slopes is based primarily on incidences of excessive erosion (not
slope stability) at similarly reclaimed portions of other mine sites in northwestern Colorado. This
concern was item 2 of our June 26, 2002 adequacy letter. From your response to this item,
Colowyo had apparently misinterpreted the concems of the Division (the response addresses the
angle at which the ditch enters East Taylor Creek). The suggestion by the Division for
reorientation of this feature was to provide additional length (reduce the gradient of the ditch
thalweg) and to provide for distance (room and space) to lessen the slopes of north aspect.
Colowyo's latest proposal to raise the region in the vicinity of E1349000 N339000 neazly 125
feet higher than currently approved appears to aggravate this problem. Reducing the height of
this newly-proposed topographic high, and shifting some of this material to the south, would
assist in reducing the steep south side of, and generally raise (partially fill in), the feature. Please
re-address this adequacy item in terms of reducing the height of the newly-proposed