REV89987

• Permit No: C1981020
• IBM Index Class Name: Revision
• Doc Date: 10/26/2007
• Doc Name: Review Memo
• From: Mike Boulay
• To: Dan Mathews
• Type & Sequence: TR23
• Media Type: D
• Archive: No

STATE OF COLORADO
DNISION OF RECLAMATION, MINING AND SAFETY
Department of Natural Resources
1313 Sherman St, Raom 215
Denver, Colorado 80203 C O L D RA D O
DIVISION OF
Phone: (3D3) 8663567 RECLAMATION
FAX: [phone] MINING
- &-
SAFETY
Bill Dwens
Governor
INTEROFFICE MEMORANDUM R"~OGGO1~
Executive Director
Ronald W. Cattany
Divislan Dimgor
TO: Dan Mathews Natural Resource Trustee
FROM: Mike Boulay ~~
DATE: October 26, 2007
SUBJECT: Munger Canyon Mine, Permit No. C-1981-020
Technical Revision No. 23 (TR-23)
I have reviewed the TR-23 application submitted by J.E. Stover & Associates, Inc. with regard to
modifications to ditch/channel specifications as requested. I have the following comments which
should be forwarded to the operator.
1. New SEDCAD utility runs were provided for ditches K, L, C, D, F, l and J for the Gob
Pile Ditches. In several instances including ditches K, D, I, and J the design discharge
was changed but the Subwatershed Hydrology Detail and Structure Summary information
contained in the original SEDCAD demonstrations beginning on page M (vii)-31 for
interim configuration and on page M (vii)-52 for Final Reclamation of the approved
permit were not updated. This hydrology detail is necessary to support the revised design
dischazges. The presentation is confusing and there are inconsistencies between the
SEDCAD demonstrations (original subwatershed hydrology detail and new utility runs
submitted with TR-23). Updated ditch and culvert summary sheets, M (vii)-29 and 51 for
the interim and reclaimed configurations, respectively show the same design dischazge
which also appears to be incorrect. Please revise the SEDCAD demonstrations,
channel utility runs, and all ditch design summary tables as appropriate, so that all
information presented in Appendix M (vri) is consistent and supported by the
subwatershed hydrology detail.
2. The Culvert Summary provided on revised page M (vii)-29 shows a peak flow of 8.8 cfs
which does not match any of the design information presented in either the interim or
reclaimed configuration SEDCAD demonstrations. There is no design information
presented for CMP-3. Please revise the Culvert Summary or SEDCAD
demonstrations as necessary to be consistent for Culvert CMP-2 and provide a
design for CMP-3.
Office of Office of
Mined Land Reclamation . Active and Inactive Mines