REV06198

• Permit No: C1982056
• IBM Index Class Name: Revision
• Doc Date: 10/29/1998
• Doc Name: MEMO FOIDEL CREEK MINE C-82-056 MR-161
• From: DMG
• To: JANET BINNS
• Type & Sequence: MR161
• Media Type: D
• Archive: No

~. - ~~- • II I I II I II I II IIII III •
999 ~ rATE OF
COLORADO
DIVISION OF MINERALS AND GEOLOGY
Deparlmeni of Natural Resources
1313 Sherman St., Room 215 y

Denver, Colorado 80203 Il
~

Phone: [phone] I
FA%: (3071 872-8106
DEPARTMENT OF
NATURAL
interoffice RESOURCES
MEMORANDUM Roy Romer
Governor
lames S Lochhead
Executive Director
to: Janet Binns Michael B. Long
Division DireUOr
~
from: By
.Walker
subject: Foidel Creek Mine, C-82-056, MR-161
date: October 29, 1998
referemce: Your memorandum of 10/28/98, same subject
In summary, the submittal does not demonstrate that runoff will be suitably controlled. With one
exception, in-put parameters of the SEDCAD 4 demonstrations appear to be appropriate. The
qualification in this statement stems from the absence of field verification of some input
parameters as indicated in this review. The demonstration is deficient in spatial relationships;
therefore, the demonstration is not appropriate to all aspects of the proposed work.
The SAE documentation consists of three parts: a cover, a drill pad SAE, and a grass filter SAE.
The cover summarizes the design approach. The drill pad SAE demonstrates that all the runoff
from azeas within the berm perimeter can be stored behind the berm. The grass filter SAE
intends to demonstrate that runoff from the outslopes of the berm is adequately treated by a grass
filter.
A number of input parameters are determined for the demonstrations. One of these input
parameters is slope. No lazge-scale drawing, with cross-sections, of the site were submitted.
Thus physical descriptions and spatial relationships are interpreted from the SEDACD4 input
and permit documentation. Map 24, Sheet 2 of 2, of the submittal provides no contour
inforn7ation. Slopes are measured as 17% in the vicinity of the site off Map 17 of the permit.
The slopes of the area are presented as 10% in the cover portion of the submittal under berm
design, 12.2% on page 6 of the containment SAE demonstration, and l0% on page 6 of the grass
filter SAE demonstration.
The area of disturbance is presented as 1.2 acre. This value was validated. 1.17 acre was
planimetered off of Map 24, Sheet 2 of 2.
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