PERMFILE104684

• Permit No: M2000113
• IBM Index Class Name: Permit File
• Doc Date: 11/16/2000
• Doc Name: MAMM CREEK GRAVEL PIT ROARING FORK RESOURCES FILE NO M-2000-113
• From: DMG
• To: GREGG SQUIRE
• Media Type: D
• Archive: No

iii iiiiiiiii u
STATE OF CO~~~.r~vv
DIVISION OF MINERALS AND GEOLOGY
Department of Natural Resources
1313 Sherman 51., Room 215
Denver, Colorado 80203
Phone: [phone]
FA%~. [phone]
DATE: Thursday, November 16, 2000
TO: Gregg Squire L
FROM: Allen Sorenson ~ /
RE: Mamm Creek Gravel Pit, Roaring Fork Resources, File No. M-2000-113
In order to evaluate geomorphic stability issues related to the Mamm Creek Pit application, the
following documents have been reviewed:
• the original application package submitted by Roazing Fork Resources;
• the Mamm Creek Pit 100 year flood plain maps prepared by Balaz and Associates;
• the letter from Grant Brothers dated October 5, 2000 discussing [he application;
• the adequacy review memo from Tom Schreiner dated November 1, 2000;
DIVISION OF
MINERALS
GEOLOGY
RECLAMATION
MINING•SAFEiY
Bill Owcns
Governor
Greg E. Walche~
&ecuuve Director
Michael B Lang
Dieision Dneetor
• the letter describing the city of Rifle's concerns with the application and dated November 1, 2000.
Based on this review, it has been determined that the following issues must be addressed before the
Division can make a recommendation to approve the Mamm Creek Pit application.
1. The application states that the estiFttnted depth of mining in the renewable resource area will be 5
feet. The shallow depth of excavation combined with the proposed 150 foot unmined barriers at
either end of the renewable resource area make it unlikely that this excavation would have
significant adverse impact on the Colorado River geomorphology. However, the language required
to make the reclamation permit enforceable must be an unequivocal commitment from the
Applicant that mining in the renewable resource area will not exceed 5 feet. Limitation on the depth
of excavation is one of the mitigating factors for in-stream gravel harvesting discussed in the
Division of Minerals and Geology "In-Stream Aggregate Extraction and Reclamation Guidance
Document," dated August 1998. As discussed in Tom Schreiner's memo, the Operator must
establish baseline cross sections in the renewable resource area with permanent survey monuments
located outside the area to be disturbed. The depth of mining can then be periodically evaluated and
documented.
The application states that the 150 foot unmined barrier at the upstream end of the renewable
resource area will include large boulders placed along the toe of the slope for stabilization of the
bank in high flow events. The Division envisions this installation as being a headcutting prevention
measure, but the configuration of the installation is not clear in the text of the application. The
Division will require that the Applicant provide sketches and/or cross-sections [o illustrate the