2011-10-11_PERMIT FILE - M2011040

• Permit No: M2011040
• IBM Index Class Name: PERMIT FILE
• Doc Date: 10/11/2011
• Doc Name: Preliminary adequacy review
• From: DRMS
• To: Rimrock Exploration and Development, Inc.
• Email Name: GRM
• 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]
Mined Land Reclamation
MEMORANDUM
STATE OF COLORADO
To: Russ Means
From: Tim Cazier, P.E.
Date: October 7, 2011
Re: Prince Albert Mine Surface Water Management — General Stormwater
Comments, Permit No. M- 2011 -040
COLORADO
D I V I S I O N O F
RECLAMATION
MINING
—&—
SAFETY
John W. Hickenlooper
Governor
Mike King
Executive Director
Loretta Pineda
Director
The Division of Reclamation, Mining and Safety (DRMS) engineering staff has reviewed the
July 20, 2011 Exhibit U, Appendix A, Surface Water Management and Control for the Prince
Albert Mine prepared by Pierce & Associates. The following comments are posed to ensure
adequate engineering analyses and design practices are implemented to eliminate or reduce to the
extent practical the disturbance to the hydrologic balance expected by the mining operation with
respect to water quality and quantity in accordance with Rules 3.1.6(1), 6.4.21(10), and 7.3.1
General Comments:
1. The UTM coordinates (Easting 0676437, Northing 4275888) on page 3, Item 11 of the
application do not appear to coincide with the PLSS location information provided in
Item 10, also on page 3 of the application. These UTM coordinates appear to be about.
4.6 miles due south of Gateway, CO and about 19 miles northwest of the site location
presented in Figure A.1. Please confirm the UTM coordinates.
2. The four sediment ponds shown on Exhibit U -1 will require dewatering to ensure
adequate detention for successive storms and for maintenance. Please provide some
discussion on anticipated sediment pond dewatering methods and frequency.
3. It is not stated in the surface water management discussion whether the designs presented
are for operations, reclamation or both. Please note that all detention ponds are required
to be designed for the 100 -year, 24 -hour storm volume for reclamation.
Specific Comments:
4. Page 21 (EPP), and Figures Exhibit U -1 and Exhibit U -3 — Orepad Area. Paragraph U
(6.a.1) indicates any runoff volume from the orepad area exceeding the 10 -year, 24 -hour
storm volume will overflow to the decline and into the underground workings. Neither
Exhibit U -i nor U -3 shows a drainage path from the Orepad Pond to the decline. Please
Office of Office of
Denver • Grand Junction • Durango Active and Inactive Mines