REV03705

• Permit No: C1981022
• IBM Index Class Name: Revision
• Doc Date: 10/7/1997
• Doc Name: SANBORN CREEK MINES C-81-022 MR 45
• From: DMG
• To: BILL CARTER
• Type & Sequence: MR45
• Media Type: D
• Archive: No

• •
STATE OF iii iiiiiiiiiiiii iii
COLORADO
DIVISION OF MINERALS AND GEOLOGY
Department of Natural Resources
131 J Sherman 51., Roam 215 `yt
Denver, Cnb*ado P~0203 I
y
Phone: [phone] Ill
fA%: (3071 832-8106
DEPARTMENT OF
NATURAL
DATE: October 7, 1997 RESOURCES
/ Roy Romer
TO: Bill Carter ~/ c°"er"°'
lames 5 Lochhcarl

FROM: Susan Burgmaier E~rcu Yve Direaur
hhchael B. Lonp
Division Duecwr
RE: Sanborn Creek Mine (C-81-022)
Minor Revision No. 45
I have completed a review of the reclamation cost estimate and surface water control portions of
OCM's MR-45 application. I have the following comments:
The cost estimate does not appear to include the cost of removal of the fence around the
shaft site. Please revise the table.
2. Does OCM's figure of .8 acres of additional disturbed azea for revegetationinclude the light
use road? Ifnot, please revise [he estimate accordingly. Please also revise the estimate [o
include grading of the light use road.
OCM estimates a disturbance area of 0.8 acres. and a topsoil replacement depth of 2.5'.
OCM estimates 3,100 cy of topsoil will be redistributed. DMG estimates 3,227 cy of
material at 2.5' over 0.8 acres. Please either revise the figure or clarify its origin.
4. OCM's cost estimate does not appearto include costs for removal ofditches SS-1, SS-2, SS-
3, and SS-4 and culvert SS-A. Please revise the estimate to include these tasks.
OCM revised page 2.05-20 by increasing the acreage at Substation No. 3 and the Facilities
Modifications. Apparentlythe increasein facilities modificationsacreage is a correction of
that which was proposed and approved in TR-29. OCM included revegetation costs for
Substation No. 3, but not for the Facilities Modifications. Please include revegetation costs
for the additional 0.5 acres in facilities modifications.
6. Once OCM's reclamation cost estimate is final, DMG will include the estimate in our
summary sheet produced for the TR-29 cost estimate. DMG will also include a new task
60a which will correct our previous error in estimating the cost to remove culvert B2.
7. Page 312 appears to contain a typographical error, but the culvert sizing is correct. The
discharge into Culvert SS-A is reported to be 90.9 cfs. The Sedcad runs indicate the
discharge is 0.9 cfs. Please review the table and revise [he discharge figure.
8. The steep (] 0%) section ofDitch SS-3 is expected to flow at 4.29 fps. While this is below
the 5 fps velocity at which rip rap would be required, it may still require rip rap.
Should you or the operator have questions or need additional information, let me know.
SLB\100797B WPW