DRC-2009-002325 - 0901a0688011d29d

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DENISOlSTi/
IVIINES
June 5, 2009
VIA PDF AND FEDERAL EXPRESS
Denison Mines (USA) Corp.
105017th Street, Suite 950
Denver, CO 80265
USA
Tel: [phone]
Fax:[phone]
www.denisonmines.com
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'Of Conirol .P Mr. Loren Morton
State of Utah Departnnent of Environmental Quality
Division of Radiation Control
168 North 1950 West
Salt Lake City, UT 84114-4850
Re: White Mesa Uranium l\1iil; Groundwater Discharge Permit No. UGW370004 -
Seeps and Springs IVIonitoring
Dear Mr. Morton:
Reference is made to the meeting at your offices on May 11, 2009, at which you, Phil Goble,
Dan Erskine and 1 discussed the proposed revisions to Groundwater Discharge Permit No.
UGW370004 (the "GWDP") for the Denison Mines (USA) Corp. ("Denison") White Mesa
uranium mill (the "Mill"). During that meeting we discussed certain matters relating to the
sampling plan (the "Plan") for seeps and springs in the vicinity of the Miii site.
Part 1.H.8 of the original GWDP required that Denison submit a plan for Executive Secretary
approval of groundwater sampling and analysis of seeps and springs found downgradient or
lateral gradient to the tailings cells on White Mesa. Part l.H.8(f) of the GWDP required that such
plan include: "Sampling and analysis of all ground water compliance parameters found on Table
2 of this Permit, including analysis of volatile and semi-volatile organic compounds by EPA SW-
846 methods 8260 and 8270."
The Plan has been drafted in accordance with Part l.H.8(f) of the Permit and currently requires
sampling for SVOCs under method 8270. The Plan has not yet been implemented in the field.
Under the current amendments to the Permit, Part I.H.8(f) is being replaced by Part l.E.6(b)(2)
which specifies that the Plan will include sampling for SVOCs in accordance with method 8270.
However, Part I.H.8(f) of the Permit was originally in error in requiring that the Plan require
sampling for SVOCs. This is because, during the finalization of the GWDP, the requirement to
sample for semi-volatile organic compounds at the groundwater compliance monitoring wells
was eliminated from the GWDP, and hence no SVOCs are listed on Table 2 of the GWDP.
Apparently, a corresponding change was not made to Part l.H.8(f) of the GWDP.
The reasons for not requiring sampling for SVOCs in the compliance monitoring wells are set
out in the December 1, 2004 Statement of Basis for the GWDP (the "Statement of Basis"),
where the Executive Secretary noted, in Sections 4.D.5) and 6) on page 19 that:
"5) Semi-VOCs Found in Tailinos Wastewater - lUC has detected five (5)
semi-VOC contaminants in tailings cell wastewater, including: bis(2-
ethylhexyl)phalate; diethyl phthalate; dimethylphthalate; di-n-butylphthalate; and
phenol (see Attachment 6, below). Four (4) of these compounds may be mobile
in groundwater environments, based on their estimated Kd values, including;
diethyl phthalate (0.07 IVKg); dimethylphthalate (0.04 IVKg); di-n-butylphthalate
(0.16 L/Kg); and phenol (0.016 L/Kg), see Attachment 8, below. However, none
of these semi-VOC contaminants were included' as compliance monitoring
parameters in the Permit, for the following reasons:
a) Several VOC contaminants have already been proposed as compliance
monitoring parameters that have lower Kd values than the semi-VOC
parameters in question. Examples of these include, but are not limited to:
acetone, chloromethane, dichloromethane, and toluene. Consequently,
these VOC parameters should be detected at the compliance monitoring
well before any arrival of the semi-VOC contaminants.
b) Focusing on the VOC contaminants will streamline groundwater
monitoring efforts and reduce associated sarripling and analysis costs for
both lUC and the Executive Secretary,
c) The Executive Secretary can add new compliance monitoring parameters
at any time, if needed to protect human health and the environment,
pursuant to Part IV.N.3 of the Permit.
6) Semi-VOCs Found in Site Groundwater - only one (1) split sampling
event included analysis of semi-VOC parameters, May, 1999. During this event
which was conducted as a part of the chloroform investigation, only one (1) semi-
VOC contaminant was detected in the lUC set of groundwater samples at the
White Mesa facility, including: Bis(2-ethylhexyl)phthalate. Unfortunately, a
problem with a laboratory blank forced the DRC to discount all its split sample
results for this parameter. Follow-up sampling for semi-VOCs was not
undertaken by DRC staff, primarily because the VOG contaminants detected are
known to generally be much more mobile in groundwater environments. The
Executive Secretary will continue with this approach 1 to semi-VOC contaminants
as compliance monitoring parameters under the Permit."
For these reasons, Denison requests that the requirement to monitor for SVOCs at the seeps
and springs be eliminated from Part 1.E.6 of the GWDP and that the Plan be amended
accordingly. The seeps and springs are much further remoyed from the Mill site than are the
compliance monitoring wells. Therefore, for the reasons discussed in Section 4.D. 5) and 6) of
the Statement of Basis, it makes no sense to sample for SVOCs at the seeps and springs if
SVOCs are not required to be sampled at the compliance monitoring wells.
If you have any questions or require any further information, please contact the undersigned.
Yours trii
David C. Fl-ydenlund
Vice President Regulatory Affairs and Counsel
cc: Ron F. Hochstein
Harold R. Roberts
Steven D. Landau
David E. Turk
DENISON
MINES
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