DRC-2011-007215 - 0901a0688025e652

State of Utah
GARY R. HERBERT
Governor
GREG BELL
Lieutenant Governor
Department of
Environmental Quality
Amanila Smith
Executive Director
DIVISION OF RADIATION CONTROL
Rusty Lundberg
Director 201 1-00 7 215
August 15,2011 • • . '
Ms. Jo Ann Tischler
Director, Compliance and Permitting
Denison Mines (USA) Corp. (DUSA)
1050 17'^ Street, Ste. 950
Denver, CO 80225
Dear Ms. Tischler:
SUBJECT: Denison Mines (USA) Corp. (DUSA) White Mesa Uranium Mill Faci^^
DRC Inspection Results: Dam Safety Inspection (Engineering Module 71)
August 9, 2011: Inspection Findings and Close-out
The subject inspection was held on August 9, 2011 at the DUSA mill facilities near Blanding,
Utah. Messrs.David Rupp of DRC and Ryan Palmer of DUSA attended the inspection, which
ended with an inspection closeout meeting, with the two individuals mentioned above and Mr.
Daniel Hillsten, the mill manager. The exterior and interior exposed perimeteijs of the taihngs
cells were observed. The following items were noted: i .
1. All the tailings cells have plastic liners on the interiors of the cell dikes. Many of the cells
do not have distinguishable exterior dikes, as they blend into the topography. There are
some distinguishable unlined dikes among the tailings cells. These are the exterior dikes
of Cells 4A and 4B. On these particular dikes there was some 1-inch wide soil cracking
noted. These cracks are a few feet long, and were only noted in a few areas, where it
appears there are small surficial clay deposits. No cracks were observed or propagated
beyond these few locations. There was no movement of any dike material observed, other
than rivulet erosion noted below.
2. We observed locations where roughly 30-foot long exterior rivulet erosion showed 1-inch
wide shallow channels in the exterior dikes at Cells 3 and 4A, an inch or two deep. These
were observed at a few places.
Although these defects appear minor, Mr. Rupp recommended to Mr. Hillsten that the above be
repaired. We further recommend that they be repaired prior to the next Dam Safety Inspection to
be performed by the Utah Dept. of Natural Resources in 2012.
195 North 1950 West • Salt Lake City, UT
Mailing Address: P.O. Box 144850 • Sah Uke City, UT 84114-4850
Telephone [phone] • Fax [phone] • T.D.D. [phone]
www.deq.utah. gov
Printed on 100% recycled paper
Page 2
This concludes the findings of this inspection. This inspection is hereby closed-out. If you have
any questions or comments on this inspection, please contact Mr. Rupp at [phone].
UTAH RADIATION CONTROL BOARD
Rusty Lundberg, Executive Secretary
DAR:dr
Cc: Mr. Dan Hillsten, DUSA
F:\drupp\DUSA\Inspections\Dam Safety 2006-2013\2011 Inspection.doc