GENERAL38081

• Permit No: M1977310
• IBM Index Class Name: General Documents
• Doc Date: 8/10/2006
• Doc Name: Supplemental Geology Report
• From: Cotter Corporation
• To: DRMS
• Permit Index Doc Type: General Correspondence
• Media Type: D
• Archive: No

cotter
July 17, 2006
Russ Means /~
Colorado Division of Minerals and Geology
RECEIVED
AUG I p 2006 ~/
C+RAND Jt1NCTiON FIELD OFFICE
RECLAMATIOI-~ g ~~.
Grand Junction Field Office
101 S. Third St, Room 301
Grand Junction, Colorado J 501
RE: Permit No. M-1977-310, JD-6 Mine, DMO Appeal; Supplemental Geology Report
Mr. Means:
A good general description of the geology of the area of the JD-6 Mine was included in
the report submitted to DMG October 19, 2005 prepared by Geoscience Services entitled
"Evaluation of Potential Contaminant Migration for Uranium Mining Operations at the
JD-6 Mine". That, and subsequent documents reported on the hydrogeologic properties
of the rock units present at the surface and underlying the mine site, including hydraulic
conductivity and sorption potentials.
The following report, map, and cross-sections are provided to give the Division more
detail on the geologic setting of the JD-6 Mine waste rock dump. This is a portion of the
supplemental information Cotter Corporation is submitting to support Cotter's appeal of
the Division's determination that the JD-6 Mine is a Designated Mining Operation.
The waste rock dump sits on relatively thin (probably 10-50 ft) Quaternary land slide
material (Qls) which predominately consists of displaced and rubblized mudstone beds of
the upper part of the Brushy Basin member of the Momson formation (Jmb) and contains
numerous boulders of various sizes. These boulders are sandstones and conglomerates
from beds of the Burro Canyon formation (Kbc). The land slide debris at the site of the
waste rock dump appears to partially overlie in-place mudstone beds of the Brushy Basin.
The Brushy Basin is very thin here due to pre-land slide erosion. Much of the dump
probably sits on land slide debris that overlies the Salt Wash member of the Morrison
formation (Jms).
The structural setting of the mine site was also previously described as located on the
southwest flank of the Paradox Valley collapsed salt anticline. Here, there are several
steep faults which have dropped blocks of various width downwazd towazd the Valley.
All of the JD-6 Mine, except for the first 700 feet of the adit, is located within a large
bock that is over one mile wide and down-dropped about 300-350 feet relative to
Monogram Mesa. The dump sits in the zone of smaller blocks. (This was shown
schematically in cross-sections submitted with the earlier reports.)
Coll-6og61Dat16iL1pJJest Slope Operations - 1 - Telephone [phone]
P.O. Box 700, 28151 DD Road, Nucla, CO 81424 USA Fax [phone]