HomeMy WebLinkAboutDRC-2009-004683 - 0901a06880142f19t£6'' .^00^' D0^lcB3
Denison Mines (USA) Corp.
105017th Street, Suite 950
OENlSOhT^MM USA
fVl INES Tel : 303 628-7798
Fax:303 389-4125
www.denisonmines.com
October 8, 2009 ^
VIA PDF AND FEDERAL EXPRESS
Mr. Dane L. Finerfrock
Co-Executive Secretary
Utah Water Quality Board x <y ^ ••
State of Utah Department of Environmental Quality ^\*>.-, -,vt-*'''
168 North 1950 West <?939^T
Salt Lake City, UT 84114-4850
Re: Public Notice of a l\/lodification to the Ground Water Quality Discharge Permit No.
UGW370004 for the White l\/lesa Mill - Comments of Denison Mines (USA) Corp.
Dear Mr. Finerfrock:
Reference is made to the Public Notice (the "Notice") of a modification to the ground water
quality discharge permit No. UGW370004 (the "Permif) for the White Mesa uranium mill (the
"Mill") operated by Denison Mines (USA) Corp. ("Denison") that was published by the Co-
Executive Secretary of the Utah Water Quality Board (the "Executive Secretary") on September
2, 2009.
Denison has the following comments on the draft modified Permit that was published with the
Notice:
1. Part l.B.
The latest data used for the October 2007 Revised Background Report for Existing Wells was
June 2007, and the latest data used for the April 2008 Revised Background Report for New
Wells was December 2007. Therefore, it would be more accurate to change the first part of that
sentence to read:
"based on groundwater samples collected through June 2007 for existing wells
MW-1, MW-2, MW-3, MW-5, MW-11, MW-12, MW-14, MW-15, MW-17, MW-18,
MW-19, MW-26 and MW-32 and through December 2007 for new wells MW-3A,
MW-23, MW-24, MW-25, MW-27, MW-28, MW-29, MW-30 and MW-31, pursuant
to ..."
2. Part I.D.6(c)
As discussed with Division of Radiation Control ("DRC") staff, Denison cannot commit to
reducing the maximum head in Cell 4A to 1 foot above the FML, nor to commit to a time frame
of 6.4 years to achieve a specific head level. The 1 foot maximum head and 6.4 year time
frame reflect the design criteria used for the slimes drain system in Cell 4A. These design
criteria are theoretical and are based on a number of assumptions and estimates. Denison
believes these assumptions and estimates to be reasonable and conservative and that the
design criteria are appropriate for Cell 4A. Denison's decision to proceed on this basis was
approved by the Executive Secretary. However, Denison cannot guarantee that the system will
perform in the future exactly as designed. This attempts to impose a level of accuracy that is
unrealistic and that is beyond Denison's control. In order to address these issues, we propose
that Part I.D.6(c) be revised to read as follows:
c) Slimes Drain Monthly and Annual Average Recovery Head Criteria - after the
Permittee initiates pumping conditions in the slimes drain layer in Cell 4A, the
Permittee will provide 1) continuous operation of the existing dewatering system,
reasonable maintenance excepted; and 2) continuous declining fluid heads in the
slimes drain layer, in a manner equivalent to the requirements found in Part
I.D.3(b) until such time as the maximum head in the tailings (as measured from
the lowest point of the upper flexible membrane liner) is 1.0 feet or less, or
otherwise approaches its asymptotic limit as approved by the Executive
Secretary.
3. Part I.E.6(h)
Paragraph 3.0 of the Mill's Sampling Plan for Seeps and Springs in the Vicinity of the White
Mesa Uranium Mill sets out a procedure for dealing with seeps and springs that are effectively
dry and cannot be sampled after repeated attempts. Those procedures do not require prior
Executive Secretary approval for the omission of samples in those circumstances. Therefore,
we suggest that Part I.E.6(h) be revised to read as follows:
h. Sample Omission - in the course of each annual sampling event, the
Permittee shall sample and analyze, or attempt to sample and analyze, all six
seeps and springs identified in Table 1 of the currently approved Sampling Plan for
Seeps and Springs in the Vicinity of the White Mesa Uranium Mill. The Permittee
shall not omit sampling of any seep or spring during said annual event, without
prior written approval of the Executive Secretary, unless the omission is in
accordance with such Plan for any seeps or springs that are dry and not capable of
being sampled."
4. Part I.E.7(f)
The phrase "If a discrepancy is identified . . ." in the last sentence of Part I.E.7(f) is vague and
difficult to apply with precision in practice. In order to provide more certainty, we suggest that
the phrase "the applicable provisions of the" be added before the word "currently" in that
sentence. This will tie the requirements of the Permit to the more specific procedures set out in
the Liner Maintenance Provisions, which are capable of being applied with precision in practice.
5. Partl.E.10
The following clarifying changes are suggested:
a) Change paragraph 10a to read "One surface impounded wastewater location at each
of Tailings Cells 1, 3, and 4A";
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b) Add the words "each of" before the word Tailings in paragraph 10b;
c) The subparagraphs in paragraph 10 should be renumberd so that there is not a repeat
of subparagraph letters a., b. and c; and
d) In subparagraph g.. Prior Notification, delete the words "fieldwork or" and add the
phrase "under lO.a, b and c" after the words "sample collection". There is no other
"fieldwork" that would require notice to the Executive Secretary under the Plan;
therefore, reference to fieldwork should be eliminated.
6. Part I.G.2
The Ground Water Compliance Limits have been set in the Permit to take into account the
mean and standard deviations or their equivalent, such that anything less than two consecutive
exceedances of the GWCLs would not be considered to be statistically significant. Therefore, if
paragraph 2(a)(1) is to be deleted, then paragraph 2(b) should also be deleted. Retaining
paragraph 2(b) is confusing, given the way that the GWCLs have been calculated, for the same
reasons that retaining paragraph 2(a)(1) would be confusing. Both paragraphs should be
deleted. They merely restate the applicable regulations. However, if paragraph 2(b) is to be
retained in the Permit, then paragraph 2(a)(1) should also be retained in the Permit. We can
see no reason for keeping one of the paragraphs and deleting the other.
7. Part I.H.4
As discussed with DRC staff on May 11, 2009, Denison does not believe that it is necessary to
add Part I.H.4 to the Permit. Further, the requirements of Part I.H.4 cannot be complied with as
drafted.
The Background Reports prepared by INTERA, Inc. demonstrate that the Mill's tailings cells are
not leaking to groundwater. The conclusions of those reports were confirmed by the University
of Utah Study, which evaluated existing wells that were considered to be the most indicative of
any potential tailings cell leakage. There is no need to perform yet another study to verify those
conclusions, particularly given the considerations below.
There are currently over 40 monitoring constituents in the Permit. These include chloride,
fluoride, sulfate and uranium which are all good indicator parameters. As discussed at our
meeting and in our June 5, 2009 correspondence with supporting INTERA memorandum, any
potential future tailings cell leakage to groundwater will be picked up by these indicator
parameters before any other constituents. There cannot be a leak to groundwater of any
significance without one or more of these parameters indicating an upward trend. However,
although an upward trend in one or more of these indicator constituents is necessary in order to
reach a conclusion that the tailings cells are leaking, a rising trend in one or more of these
constituents does not necessarily imply that the tailings cells are leaking. Rising trends in
indicator parameters could also be due to natural influences.
As we discussed in our May 11, 2009 meeting, nothing will be gained from characterizing at this
time the chemical composition, noble gas composition, and age of the groundwater in the wells
that were not covered by the University of Utah Study. Any potential future exceedance of a
GWCL would be evaluated at the time of the exceedance by the most appropriate methods in
the circumstances. This would most likely include a spatial and temporal analysis of the
constituent in question together with all other constituents in the well, with a primary focus on
the indicator parameters. If such an analysis is not conclusive, such as when one or more
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indicator parameters have also risen or have demonstrated an upward trend or trends and
natural influences cannot be ruled out, then a further analysis would be performed. This
analysis may include an isotopic analysis, depending on the circumstances. If an isotopic
analysis were to be performed at that time, then the results of that analysis would be relevant,
not the results of an isotopic analysis performed today.
In addition to the fact that the analyses contemplated by Part I.H.4 are not necessary and will
provide little, if any, information relevant to the analysis of a potential future GWCL exceedance,
there are a number of practical problems associated with such an analysis. As we discussed at
our May 11, 2009 meeting, the analyses contemplated by Part I.H.4 are not mainstream (i.e.,
there are no generally accepted methods), they are costly to perform, they are not capable of
being performed at commercial laboratohes, and they cannot be performed in the 90-day time
frame proposed in Part I.H.4.
The required analysis can only be performed at a limited number of university laboratories.
Those laboratories are not Utah-certified and there are no EPA-approved methods for such
analyses. Further, Denison cannot control the timing and results from such non-accredited
laboratories. This is because Denison would not have a choice of commercial laboratories from
which to obtain all of the required work. For example, Denison took splits of the samples taken
by the University of Utah in July 2007 and engaged one of the few available other university
laboratories to perform the tritium/helium analysis. After six months of waiting for the analytical
results, and being deferred behind other university projects, Denison finally called off the
analysis. Denison cannot be held responsible for failure to meet a schedule when such failure
is not within its control.
It took the University of Utah approximately one year to complete its study. Planning started in
the Spring of 2007, fieldwork was performed in July, 2007 and the final report was issued in
May, 2008. It is unrealistic to expect that Denison could have such a study performed in the 90
days contemplated by Part I.H.4. A more realistic time frame would be 365 days, as required by
the University of Utah. However even a time frame of 365 days may not be achievable, given
Denison's inability to control the schedule of the non-commercial laboratory or laboratories that
would be required to perform the analysis.
In summary, the evaluations required by proposed Part I.H.4 are not necessary to establish that
the Mill's tailings cells have not leaked to date; they will provide little, if any, information that
could be of use in evaluating a potential future tailings cell leak; will be costly; will not be
performed in accordance with accepted EPA guidance, will take at least one-year to complete;
and the timing of completion of the study will not be within Denison's control. As a result,
proposed Part I.H.4 should be eliminated from the Permit.
8. Part I.H.5
Once the new decontamination pad is constructed. Mill personnel will be able to check the leak
detection system weekly and will be able to take the pad out of service annually in order to
inspect the integrity of the steel liner in each of the settling ponds and the visually exposed
surface areas of the concrete pad. However, it will not be possible to inspect the integrity of the
concrete surfaces below the steel liner in each tank, as it will not be possible to remove the steel
liner from each tank. Inspections of such concrete surfaces are not necessary, given the fact
that the tanks are lined with steel liners, a leak detection system is checked weekly, and the
integrity of the steel liners is checked annually. References to concrete surfaces should
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therefore be removed from Part I.H.5, or it should be made clear that only visually exposed
areas of the concrete pad need to be inspected annually and that this does not include areas
under the steel tank liners.
If you have any questions or require any further information, please contact the undersigned.
We suggest that we have a call to discuss the foregoing comments and your responses to them,
prior to finalization of the Permit language.
Yours truly.
F rydenlund
P'resiaent Regulatory Affairs and Counsel
cc: Ron F. Hochstein
Harold R. Roberts
Steven D. Landau
David E. Turk
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