2011-06-01_REVISION - C1981019 ‎(4)‎

• Permit No: C1981019
• IBM Index Class Name: REVISION
• Doc Date: 6/1/2011
• Doc Name: Adequacy Review ‎(Memo)‎
• From: Kent Gorham
• To: Janet Binns
• Type & Sequence: MR108
• Email Name: KAG
• Email Name: JHB
• Email Name: DIH
• 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]
Interoffice Memo
COLORADO
D I V I S I O N OF
RECLAMATION
MINING
SAFETY
To: Janet Binns
From: Kent Gorham ?aj
CC: Dan Hernandez
Date: June 1, 2011
RE: Adequacy Review Memo, MR-108, Colowyo Mine, C-81-019
I have completed my review of the materials received from Colowyo on May 2, 2011 for MR-
108 for the Colowyo Mine, #C-81-019. Reviewed were Figure 1, Map 19, titled "Edits for MR-
108" and revised Map 19 Post Mining Topography. Map 19 is the permit map that represents
the approved post mining topography for all areas mined and/or disturbed over the life of the
operation. Map 19A also represents the approved post mining topography for other areas of
the mine but is not the subject of this revision. I also reviewed Map 29 Spoil Grading which
depicts the approved post-mining topography and the areas and dates of planned regarding
of all disturbed areas.
The applicant is proposing to change the approved post mining topography on Map 19 in the
areas of lower Prospect drainage, the lower portion of the North Tributary Ditch, and the
lower portion of the Final East Pit ditch. According to comments made by the applicant
during an on-site meeting on April 5, 2011, the changes were necessary in areas of the East
Pit that were the subject of NOV CV-2010-004. This would include the Final East Pit Ditch,
reach 1, stations 00+00 to 10+41 and the North Tributary East Pit Ditch, reach 1, stations
00+00 to 11 +17.
Please explain why areas were not regraded in accordance with the approved post
mining topography in effect in 2009 when the original work was completed in the 2009
field season. Many significant discrepancies exist that are not related to drainage
locations.
2. MR-108 proposes changes to the approved post mining topography in the lower
section of the Prospect drainage. Division notes (D. Hernandez) from the April 5, 2011
meeting at Colowyo discussing this matter read:
"Regarding another matter, the company informed us that the actual on-the-ground
topography of a portion of its 2009 reclamation just southeast of the East Pit's 2010
reclamation polygon does not match the company's approved post-mining topography map.
According to the company, this mis-match was part of the reason for their most recent NOV.
Office of Office of
Mined Land Reclamation Denver • Grand Junction • Durango Active and Inactive Mines