DRC-2010-006021 - 0901a068801dcfd7

State of Utah
GARY R. HERBERT
Goveriiof
GREG BELL
Lieiiteiiaiit Governor
Department of
Environmental Quality
Amanda Smith
E.\eriitive Director
DIVISION OF RADIATION CONTROL
Riisly Lundberg
Director
C=2010-006021
November 15, 2010
Certified Mail
(Retum Receipt Requested)
Mr. Harold R. Roberts
Vice President, US Operations
Denison Mines (USA) Corp (DUSA)
1050 l?'*" Street, Suite 950
Denver, CO 80265
Dear Mr. Roberts:
SUBJECT: Denison Mines (USA) Corporation (DUSA) White Mesa Mill Facility
DRC Cell 4B Construction Inspection November 3, 2010
Observations Regarding Sandbags and other Items
On November 3, 2010 I visited the subject construction site and had several observations, noted
below:
1. Sandbags in Cell 4B. I discussed the placement of the sandbags covering the slimes drains
concurrently with Messrs. Dave Turk and Steve Snyder of DUSA, as well as Michael
Beaman of AEGL, the lining contractor. It appeared that all placed bags had been
reoriented now, piggy-backed onto each other, like fallen dominoes. I pointed out that this
placement method creates numerous voids, opening to the slimes drains.
The approved plans and specifications show the bags to be butted on long edge, and to
have a 3-inch depth. Your earlier letter of October 8, 2010 mentions that, "Denison Mines
(USA) Corp.. .instructed the contractor responsible for the sand bag installation to bring
the currently installed sandbags, and all subsequent installed sandbags, into full
compliance with the approved plans and specifications." Apparently, that effort had not yet
been started.
We reoriented a pair of sandbags in the manner of the specifications. It seemed such
reorientation of existing sandbags could be accomplished fairly rapidly. AEGL plans to
begin reorienting the bags after completion of the liner placement. In later discussion that
day on this topic with Mr. Bartlett of DUSA, he expressed concem that if there is delay,
frozen sandbags may be nearly impossible to reorient correctly.
195 North 1950 West • Salt Uke City. UT
Mailing Address: P.O. Box 144850 • Salt Lake City, UT 84114-4850
Telephone [phone] • Fax [phone] • T.D.D. [phone]
www.tieq.Utah.f;w
Printed on lOO'Ji recycled paper
Page 2
2. Cell 4A Freeboard. The current freeboard for Cell 4B is approved as 5593.74 famsl. This
is 4.76 feet below the FML. A spillway was being constructed between Cells 4A and 4B.
The upper elevation of the spillway is designed to be at the elevation of 5596.3 famsl or
2.46 feet above of the current freeboard limit. However, the water level in Cell 4A
appeared to be about 10 vertical feet below the spillway. According to the proposed DMT
Plan version 10.1, which is near approval, once Cell 4B is approved to receive mill
discharge, the freeboard limit for Cell 4A becomes zero.
However, Cell 4B is not yet completed, and approved for use. If Cell 4B will not be
completed this calendar year, a new freeboard limit for Cell 4A will need to be established.
3. Completion of Cell 4B. Completion of the cell this calendar year, as discussed above,
depends on the weather. There was some weather related damage to the liner leak
detection system (LDS) sumps from bulging was created by water entering the system.
Apparently, infiltration into the LDS was not being prevented, and there was not an
adequate pump installed to remove the water from the sump area.
We discussed that winter shutdown provisions may be needed. DUSA and AEGL are
determined to finish the work this autumn. However, if such is not possible winter
shutdown provisions would need to be implemented rapidly. An important part of a winter
shut-down would be provisions for preventing and handling of leakage into the LDS.
The lining contractor stated he expected to be done with all lining work in ten days, and
completely done with the project by Thanksgiving Day. I plan to retum to the site to
check progress.
4. Placement of Cell 4B Excavated Soils on Cell 3. Dave Turk of DUSA and I discussed that
the original drawings called for 4 feet of excavated soils from Cell 4B to be placed on the
east side of tailings Cell 3. Mr. Turk noted that this was not done. However, some
excavated soils were placed on the west side of Cell 3. This change from the original
plans will need to be included on the as-built drawings.
If you have any questions on the above, please contact me.
Sincerely,
David A. Rupp, P.E.
Geotechnical Services Section
DR:dr
FACell 4B\Constr\LtrRe 03NovI0 Observations.doc