2014-04-02_REVISION - C1981012

• Permit No: C1981012
• IBM Index Class Name: Revision
• Doc Date: 4/2/2014
• Doc Name: Review of Diversion Ditch Design
• From: Susan Burgmaier
• To: Leigh Simmons
• Type & Sequence: TR69
• Email Name: SLB
• Email Name: LDS
• Email Name: SB1
• Media Type: D
• Archive: No

DIVISION OF RECLAMATION, MINING AND SAFETY
Department of Natural Resources
1313 Sherman St., Room 215
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
STATE OF COLORADO
COLORADO
ID IV I S I O N O F
RECLAMATION
MINING
SAFETY
John W. Hickenlooper
Governor
April 2, 2014
Mike King
Executive Director
To: Leigh Simmons Loretta E. Pineda
Director
From: Susan Burgmaier
Re: New Elk Mine (Permit No. C- 1981 -012)
Technical Revision No. 69
Preliminary Adequacy Review
Per your request, I have reviewed NECC's application for Technical Revision No. 69. 1 have the
following comments for referral to NECC.
1. The cover letter for the revision indicates that the revision has been prepared to address design
criteria for RDA Clean Water Diversion Ditch D -55. The RDA Clean Water Diversion Ditch and Ditch
D -55 are not one in the same. Ditch D -55 is the portion of the diversion that borders the western
edge of the RDA, roughly between Stations 30 +00 to 41 +00 on the 1 -31 -2014 plan view provided by
NECC. The northern and eastern diversion sections from Stations 30 +00 to 0 +00 are the RDA Clean
Water Diversion Ditch. Ditch D -55 drains a smaller watershed and is a steeper channel section than
the RDA Clean Water Diversion Ditch.
The design for D -55 is presented in Exhibit 19(24) pages 24 -26, and further described on page 2.05 -
11a. Ditch D -55 is also shown on Map 13, East Portal Sediment and Surface Water Control Plan,
approved with TR -66. The basis for the design includes:
• Watershed area 9.1 acres
• Design discharge of 13.9 cfs.
• The approved design shows the ditch is trapezoidal, with a minimum depth of 1.6', bottom
width of 3', 2:1 sideslopes, and requires 3" rip rap lining.
• The overall gradient of the ditch is 9 %.
We are unable to locate the design for the RDA Clean Water Diversion Ditch in the approved permit
application, but did locate the following related information:
• Culverts C75 and C76 are located in the East Branch of the RDA Diversion Ditch. The design
information for these culverts, located in Exhibit 19(19) indicates that the drainage area is 25.9
acres and the runoff is 51.82 cfs.
• Exhibit 20 includes a discussion of the RDA contour ditch designs. Table 9 of Exhibit 20 provides
ditch details. On Table 9, the minimum contour ditch depth for a 50 cfs flow, allowing for 1.0'
of freeboard is 3.5'. The ditches will be triangular in shape and will not require rip rap.
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Mined Land Reclamation Denver • Grand Junction • Durango Active and Inactive Mines