DRC-2010-002840 - 0901a06880186f68

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State of Utah
GARY R. HERBERT
Govemor
GREG BELL
Lieutenant Governor
Department of
Environmental Quality
Amanda Smith
Acting Executive Director
DIVISION OF RADIATION CONTROL
Dane L. Finerfrock
Director
April 29, 2010
CERTIFIED MAIL
(Retum Receipt Requested)
David C. Frydenlund
Vice President and General Counsel
Denison Mines (USA) Corp. (DUSA)
1050 Seventeenth Street, Suite 950
Denver, CO 80265
Dear Mr, Frydenlund:
SUBJECT: Utah Radioactive Materials License (RML) No. UTI900479 Proposed License
Amendment #4; Table of DUSA DMT Plan History. ..; November 18, 2009 DUSA Letter,
GeoSyntec Consultants, Computations; October 8, 2009 DRC Letter, Request for
Information; Table of Cell 4A BAT O&M Plan History. . .;December 11, 2008 DUSA
Letter, Amendment Requests Relating to Freeboard Limit Calculations for Tailings Cells;
Freeboard Calculation Method for Cell 4A FeasibUity and Request for Information
In the subject letter dated December 11, 2008, DUSA first proposed a new method to calculate the
freeboard for tailings Cell 4A at the White Mesa Mill. The method is discussed in detail in Section 5 of
that letter, and an example calculation is given in Appendix A ofthe same.
In conjunction with the proposed Freeboard Calculation Method, adjustments were proposed to several
documents. These documents include the Radioactive Materials License (RML), the DMT Plan, the Cell
4A BAT O&M Plan, the, and the Ground Water Discharge Permit. However, not all items necessary for
the issuance or approval of these documents have been completed.
After review ofthe subject Freeboard Calculation Method, we find it feasible and could move forward to
approving such, after completion of the following:
1. The Upcoming RML Amendment. The subject RML Amendment #4 is currendy being
advertised for public comment. Adjustments to License Condition 10.3 were made to
accommodate the subject new Freeboard Calculation Method and future methods. New
License Condition 10,3.c in the subject amendment resolves concems relating to storm water
overtopping dikes, as discussed in the subject October 8, 2009 DRC Letter and the subject
November 18, 2009 DUSA Letter which contains some GeoSyntec Consultant computations
regarding the matter.
It was the intent of the DRC to change the reporting date for the Annual Technical Evaluation
Report (ATER) to be November 15"^ of each year, to coincide with the annual freeboard
calculation date of November 1^' of each year when using the new Freeboard Calculation
168 North 1950 West • Salt Lake City, UT
Mailing Address: P.O. Box 144850 • Salt Lake City, UT 84114-4850
Telephone [phone] • Fax [phone] • T.D.D. [phone]
www.deq.utah.gov
Printed on 100% recycled paper
David C, Frydenlund
April 29, 2010
Page 2
Method. Earlier, we discussed this proposed schedule with Harold Roberts of DUSA. He felt
it to be reasonable. Therefore, it is our intent to modify License Condition 12,3, to change the
submittal date for the ATER to November 15* of each year. Since this change is only minor, it
will be included in the final issued RML Amendment #4, following the current public
comment period.
2. A Revised DMT Plan, The White Mesa Mill Tailings Management System and Discharge
Minimization Technology (DMT) Monitoring Plan is known as the DMT Plan. The plan has
included freeboard controls in the past. Table 2 which is titled DUSA DMT Plan History... is
attached. Several versions of the plan have been generated. The table shows that the most
current DMT Plan approved, i.e. 3/10 Revision: Denison-7 does not contain all previous
adjustments needing to be in the plan.
We request the DMT Plan be revised, given a new and unique version number, as a header on
each sheet of the plan, and be submitted for approval. The proposed version will need to
include the appropriate adjustments from the DMT Plans proposed in the DUSA letters of
November4, 2008, May 26, 2009 and March 22, 2010. Additionally, we request that in
Appendix A of the DMT Plan, Table II. Operation Systems, that a line be added in the table,
for any observable FML liner damage.
3. A Revised Cell 4A O&M Plan. The Cell 4A BAT Monitoring, Operations, and Maintenance
Plan is known as the Cell 4A O&M Plan. Table 3, which is titled Cell 4A BAT O&M Plan
History. . ., is attached. The table shows that the mostly recent approved Cell 4A O&M Plan
is 3/10 Revision Denison 1,4. However, this version does not contain all the appropriate
adjustments made in a proposed version 05/09 Revision Denison 1.5, submitted May 26, 2009,
We request the latest Cell 4A O&M Plan be respectively revised, given a new and unique
version number, as a header on each sheet of the plan, and be submitted for approval.
As a result of the Freeboard Calculation Method, the freeboard limits for the tailings cells at the White
Mesa Mill will need to be adjusted. The freeboard is defined as being the distance from the water level to
the top of the lowest FML on any dike. The freeboard limits for the various cells will be adjusted as shown
in Table 1 below:
Table 1
Freeboard Limits for the Various Tailings Cells
As a Result of the New Freeboard Ca culation Method for Cell 4A
Tailines Cell No. Freeboard Limit Comment
1 5,615.4 famsl Current L.C. 10,3 Requirement
2 None Cell has an interim cover
3 None Freeboard is not applicable; PMP flood volume
from Cell 3 will be attributed to Cell 4A.
4A 5,593.7 famsl When maximum beach elevation is 5593 famsl
or less. A freeboard of 4,76 feet below the
FML to accommodate the 159,4 ac-ft PMF for
Cell 2 through Cell 4A.
4A Varies When maximum beach elevation is above 5593
famsl, the Cell 4A freeboard is determined by
the formulas provided in DUSA letter of Dec.
11,2008.
David C. Frydenlund
April 29, 2010
Page 3
This change to the Freeboard Calculation Method for Cell 4A is to be an improvement to the freeboard
determination methods currently used. It develops more realistic freeboard heights. The previous
freeboard determination method could produce more unrealistic freeboard limits, especially as tailings cells
became full.
Annually on November 1, by using the subject method, a calculated future pool area for the coming year is
divided into the maximum runoff volume into Cell 4A. This establishes the freeboard height necessary for
the coming year. Example calculations of the Freeboard Calculation Method are included in Appendix A
of the subject December 11, 2008 DUSA letter.
The subject method used to determine the pool area appears quite logical. It involves a series of equations.
These equations calculate a freeboard for the year by first deriving a future pool area, as mentioned above,
by using a conservative projected taihngs tonnage to be deposited in Cell 4A. On November 1*' of each
year, the actual tonnage deposited is used to calculate a current existing pool area. However, this is
followed by again using conservative projected tailings tonnage to be deposited in Cell 4A, which derives a
projected pool area and the resultant freeboard for the year to the coming November 1.
The method is based on the premise that on average, once the cell has received enough tailings solids to
form a beach area, the pool surface area of the cell will be expected to decrease in direct proportion to the
decrease in total available space in the cell for tailings solids storage.
We request you submit final versions of the documents discussed in items 2 and 3 above, to move forward
toward DRC approval of the subject Freeboard Calculation Method for Cell 4A, at your eariiest
convenience. If you have any questions on this matter, please contact me.
Sincerely,
David A. Rupp,
Geotechnical Services Section
DAR:LBM:dr
Attachments:
1. Table 2: DUSA DMT Plan History...
2. Table 3: Cell 4A BAT O&M Plan History.
Cc: Harold R. Roberts, DUSA
F:\drupp\DUSA\LRAiS:License Amendment\Fb Amend. 2009\FeasibiJi(y Freeboard CafcMcthod 04-29-2010.doc
File: Documemum
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