DRC-2012-001437 - 0901a068802d22fd

DENISON
MINES
Dii Denison Mines (USA) Corp
1050 17th Street, Suite 950
Denver, CO 80265
USA
Tel [phone]
Fax [phone]
www denisonmines com
May 11, 2012
VIA PDF AND FEDEX
Rusty Lundberg,
Co-Executive Secretary
Utah Water Quality Board
Utah Department of Environmental Quality
195 North 1950 West
P.O. Box 144850
Salt Lake City, UT 84114-4850
7e
m 20)2
division,-.f
SI
J /
C-2012-001437
Re: State of Utah Ground Water Discharge Permit No. UGW370004
White Mesa Uranium Mill - Notice Pursuant to Part I.G.I (a)
Dear Mr. Lundberg:
The White Mesa Mill (the ''Mill'') performed first quarter ("Ql") groundwater monitoring during
the period from January I, to March 31, 2012 under the July 14, 2011 version of the Mill's
Groundwater Discharge Permit (the ''GWDP"). All analytical data needed for comparison to the
GWCLs were received during the period ending April 12, 2012.
Pursuant to Part I.G. l.a) ofthe GWDP, (July 14, 2011) please take notice that the concentrations
of specific constituents in the monitoring wells highlighted in yellow and bold italics in the
columns for this quarter in the attached Table 1, exceeded their respective GWCLs. For ease of
review. Table 1 has been formatted to simplify the tracking of any continued exceedances from
one monitoring period to the next by charting ongoing monitoring of the same well in the same
row, and by highlighting exceedances (in color and bold italics).
Part LG.l c) of the GWDP states "that the Pennittee shall prepare and submit within 30 calendar
days to the Executive Secretary a plan and a time schedule for assessment of the sources, extent
and potential dispersion of the contamination, and an evaluation of potential remedial action to
restore and maintain groundwater quality to ensure that Permit limits will not be exceeded at the
compliance monitoring point and that DMT or BAT will be reestablished." The summary below
relating to the first quarter 2012 exceedances includes, for each exceedance, a brief di.scussion of
whether such a plan and schedule is or is not required or appropriate at this time in light of other
actions currently being undertaken by Denison, as determined by Utah Department of
Environmental Quality (UDEQ) Staff and as stated in teleconferences with Denison on April 27
and May 2, 2011. Based on the assessments noted below relating to the first quarter
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exceedances, a plan and schedule for the first quarter 2012 exceedances will not be required for
the following reasons. A Plan and Time Schedule will not be prepared for monitoring wells with
two successive exceedances in Ql 2012 if successive exceedances were reported in a previous
quarter and were included in the Plans and Schedules submitted June 13, 2011, September 7,
2011 and amended April 13, 2012. A Plan and Time Schedule will not be submitted because the
assessment processes and schedule have not changed since these previous submissions.
Additionally, a Plan and Time Schedule will not be prepared for successive exceedances of
nitrate + nitrite, chloride, chloroform, methylene chloride and pH because these constituents
have been the subject of ongoing investigations at the Mill as discussed below.
One new successive exceedance was reported in Ql 2012 in MW-31 for Total Dissolved Solids
("TDS"). As discussed in detail below, a separate Plan and Time Schedule will not be submitted
for this exceedance. The successive TDS exceedances reported in Ql 2012 will be added to, and
addressed in conjunction with the sulfate exceedances as described in, the June 13, 2011 Plan
and Time Schedule.
Under the July 14, 2011 revision of the GWDP, GWCLs have been determined on a well-by-
well basis to refiect background groundwater quality, as defined by the mean plus second
standard deviation concentration, or the equivalent. Accordingly, the GWDP requires that
constituent concentrations in each monitoring well shall not exceed the GWCLs set out in Table
2 of the GWDP. It should be noted that, because the GWCLs have been set at the mean plus
second standard deviation, or the equivalent, un-impacted groundwater would nomially be
expected to exceed the GWCLs approximately 2.5^ of the time. Therefore, exceedances are
expected in approximately 2.5% of all sample results, and do not necessarily represent impacts to
groundwater from Mill operations.
The following are items of note relevant to all exceedance data presented herein:
1. Nitrate + nitrite and chloride in monitoring wells at the site have been the subject of
ongoing investigations at the Mill. Based on the results of the previous investigations
Denison and the Executive Secretai-y acknowledge that it has not been possible to date to
detemune the source(s), cause(s), attribution, magnitudes of contribution, and
proportion(s) of the local nitrate + nitrite and chloride in groundwater. Denison
submitted a Corrective Action Plan ("CAP") for nitrate -i- nitrite and chloride in
groundwater. The CAP is cunently under revision in response to DRC comments and
was resubmitted on May 7, 2012. Based on information provided by UDEQ in
teleconferences on April 27, and May 2, 2011, due to the ongoing activities and actions,
the 30-day plan and schedule for assessment is not required for nitrate -f- nitrite and
chloride exceedances at this time.
2. As discussed in previous quarterly groundwater sampling reports, the background levels
and GWCLs for pH were established based on eight or more quarters of laboratory data,
which are historically higher than field data due to effects from the evolution of carbon
dioxide, and subsequent increa.se in pH from field to lab. Denison's letter to the Co-
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Executive Secretary of the Utah Water Quality Board dated January 31, 2011 proposed
the recalculation of the GWCLs for tleld pH. Foilowing the statistical evaluation of pH
data by Denison's geochemical consultant, ENTERA, Inc., Denison compared the Mill's
most recent groundwater pH data from the second quarter of 2011, including accelerated
sampling results as recent as June 2011, and noted that all of the June 2011 groundwater
results, and many of the other results from the second quailer, were already outside the
revised GWCLs that were to be proposed in the June 30, 2011 letter. By the letter dated
June 30. 2011, Denison proposed to submit to DRC a Work Plan and Schedule to
complete investigations to address the site-wide pH issue, following a meeting with DRC,
to discuss Denison's findings to date and to agree upon the steps and milestone dates to
be incorporated in the Work Plan and Schedule. Pursuant to teleconferences with DRC on
December 5, and December 19, 2011, Denison submitted the Work Plan and Schedule on
January 20, 2012. The Work Plan and Schedule are currently under review by DRC.
Based on information provided by UDEQ in teleconferences on April 27, and May 2,
2011 and due to the cun-ent commitment to evaluate site field pH conditions, the 30-day
plan and schedule for assessment is not required for field pH exceedances.
1.0 Exceedances in Required Quarterly Sampling Wells
1.1 Quarterly Wells with Two Successive Exceedances
As indicated in the attached Table 1, the analytes discussed below exceeded their respective
GWCLs for two successive sampling periods in the tlrst quiirter 2012. However, the 30-day plan
and schedule contemplated in Part I.G.I c) ofthe GWDP will not be required for these particular
consecutive exceedances which first occurred in the first quarter of 2012 , for the reasons stated
below. One time exceedances and non-successive exceedances are noted on Table 1, but not
listed below. Consecutive exceedances which occurred in previous reporting periods are
discussed in the respective 30-day plan and schedule for that quarter.
MW-26
Nitrate + nitrite concentration exceeded its GWCL in all sampling events during the first
quarter 2012. As mentioned above, nitrate -i- nitrite concentrations are currently under re-
evaluation, and a plan to address this consecutive exceedance is not necessary and is not
being subnntted.
Uranium concentration exceeded its GWCL in the January monthly and Ql (February)
sampling events. Uranium concentrations exceeded the GWCLs in two consecutive
sampling events in 2010. The con.secutive uranium exceedances noted in MW-26 were
previously discussed in the Ql 2011 Plan and Time Schedule Under Part I.G.4 (d).
submitted to UDEQ on June 13, 2011 and revised on April 13, 2012. An additional plan
or schedule to address the Ql exceedances is not necessary and is not being subnntted
because the assessment proces.ses and schedule have not changed since the June 13, 2011
and April 13, 2012 submissions.
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• Chloroform in MW-26 has exceeded its GWCL for all of the monitoring periods for Ql
2012. MW-26 IS used as a pumping well for the ongoing chloroform capture program
and is expected to yield increased concentrations of chloroform.
• Methylene chloride in MW-26 exceeded its GWCL all of the monitoring periods for Ql
2012. MW-26 IS used as a pumping well for the ongoing chloroform capture program and
is expected to yield increased concentrations of methylene chloride.
MW-26 Note: As stated in the September 2009 Statement of Basis (page 23) in support of the
January 20, 2010 revisions to the GWDP, "[i]t should be noted that, because MW-26 is a
pumping well for chlorofonn removal, concentrations of all constituents in that well are subject
to potential variation over time as a result of the pumping activity. This will be taken into
account by the Executive Secretary in detennining compliance for this well." Based on
information provided by UDEQ in teleconferences on April 27, and May 2, 2011, due to the
current pumping status as part of the chloroform investigation program, the 30-day plan and
schedule for assessment is not required at this time for exceedances of chloroform and methylene
chloride in MW-26.
• Chloride concentration exceeded its GWCL in the December and January sampling
events. As mentioned above, chloride concentrations are currently under re-evaluation
and a plan to address this consecutive exceedance is not necessary and is not being
submitted.
MW-30
• Nitrate -i- nitrite concentration exceeded its GWCL in all sampling events during the first
quarter 2012 and during previous quarters. As mentioned above, nitrate -i- nitrite
concentrations are currently under re-evaluation, and a plan to address this consecutive
exceedance is not necessary and is not being submitted.
• Selenium concentration exceeded its GWCL in the Ql (February) and the March monthly
sampling events during the first quarter 2012. The consecutive selenium exceedances
noted in MW-30 in Ql 2012 were previously discus.sed in the Ql 2011 Plan and Tune
Schedule Under Part I.G.4 (d), submitted to UDEQ on June 13, 2011 as revised on Apnl
13, 2012. An additional plan or schedule to address the Ql exceedances is not necessary
and IS not being submitted because the assessment processes and schedule have not
changed since the June 13, 2011 and April 13, 2012 submissions.
MW-3
Nitrate + nitrite concentration exceeded its GWCL in all sampling events during the first
quarter 2012 and during previous quarters. As mentioned above, nitrate -i- nitnte
concentrations are currently under re-evaluation, and a plan to address this consecutive
exceedance is not necessary and is not being submitted.
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• Chloride concentration exceeded its GWCL in all sampling events during the first quarter
2012. As mentioned above, chloride concentrations are currently under re-evaluation,
and a plan to address this consecutive exceedance is not necessary and is not being
subnntted.
• TDS concentration exceeded its GWCL in the December 2011 and January 2012 monthly
sampling events. As noted above, a separate Plan and Time Schedule will not be
submitted for this exceedance. The successive TDS exceedances reported in Ql 2012
will be added to, and addressed in conjunction with the sulfate exceedances as described
in, the June 13, 2011 Plan and Time Schedule. The rationale for addressing the TDS and
sulfate together is based on the connection of sulfate to TDS, that is, sulfate is a
component of TDS. The time schedule for the assessment of TDS will be the same as
that for sulfate.
• Sulfate concentration exceeded its GWCL in the January monthly and Ql (Febmary)
sampling events. Sulfate concentrations also exceeded the GWCLs in two consecutive
sampling events in Ql 2011. The consecutive sulfate exceedances noted in MW-31 in
Ql 2012 were previously discussed in the Ql 2011 Plan and Tune Schedule Under Part
I.G.4 id), submitted to UDEQ on June 13. 2011 as revised on Apnl 13, 2012. An
additional plan or schedule to address the Q4 exceedances is not necessary and is not
being submitted because the assessment processes and schedule have not changed since
the June 13, 2011 and Apnl 13, 2012 submissions.
MW-35
Manganese concentration exceeded the GWCL in MW-35 in all of the Ql sampling
events. The consecutive manganese exceedances noted in MW-35 were previously
discussed in the Plan and Time Schedule Under Part I.G.4 (d), subnntted to UDEQ on
September 7, 2011 as revised on January 20, 2012. An additional plan or schedule to
address the Ql exceedances is not necessary and is not being subnntted because the
assessment processes and schedule have not changed since the September 7, 2011 and
April 13, 2012 subnnssions. It should be noted that background has not yet been
established for MW-35 and that the interim GWCLs for MW-35 have been set at a
fraction of the Groundwater Quality Standards pending the determination of background.
Therefore, exceedances of the interim GWCLs do not necessarily represent impacts to
groundwater from Mill activities.
Uranium concentration exceeded the GWCL in MW-35 in all ofthe Ql sampling events.
The consecutive uranium exceedances noted in MW-35 were previously discussed in the
Plan and Time Schedule Under Part I.G.4 (d), subnntted to UDEQ on September 7, 2011
as revised on April 13, 2012. An additional plan or schedule to address the Ql
exceedances is not necessary and is not being submitted because the assessment
processes and schedule have not changed since the September 7, 2011 and April 13, 2012
submissions. It should be noted that background has not yet been established for MW-35
and that the interim GWCLs for MW-35 have been set at a fraction of the Groundwater
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Quality Standards pending the determination of background. Therefore, exceedances of
the interim GWCLs do not necessarily represent impacts to groundwater from Mill
activities.
• Gross alpha concentration exceeded the GWCL in MW-35 in all of the Ql sampling
events. An additional plan or schedule to address the Ql exceedances is not necessary
and is not being subnntted because the background has not yet been established for MW-
35, and the interim GWCLs for MW-35 have been set at a fraction of the Groundwater
Quality Standards pending the determination of background. Therefore, exceedances of
the interim GWCLs do not necessarily represent impacts to groundwater from Mill
activities.
Thallium concentration exceeded the GWCL in MW-35 in the Ql (Febmary) and March
monthly sampling events. An additional plan or schedule to address the these
exceedances is not necessary and is not being subnntted because the background has not
yet been established for MW-35, and the interim GWCLs for MW-35 have been set at a
fraction of the Groundwater Quality Standards pending the detemnnation of background.
Therefore, exceedances of the interim GWCLs do not necessarily represent impacts to
groundwater from Mill activities.
1.2 Quarterly Wells with New Exceedances Reported in Ql
New exceedances for the Ql 2012 quarterly well sampling program are listed below. The
exceedances listed will result in an accelerated sampling frequency from quarterly to monthly. It
is important to note that the wells listed below will only be sampled during the monthly events
for those constituents which exceeded the GWCLs. The wells listed below will be sampled for
all constituents listed in the GWDP during the quarterly events as that is the regularly scheduled
sampling for the quarterly wells.
• Selenium in MW-35 exceeded the GWCL in the Febmary (Ql) sampling event.
Relative to accelerated reporting requirements, based on phone conversations with UDEQ on
Apnl 5, 2010, that reporting of exceedances is required to be completed within 30 days of receipt
of the last data package for a quarterly monitoring event. Similarly, accelerated monitoring is
required to commence the month following the submission of the Exceedance Notice for a
specified quarter for wells that are being accelerated from quarterly to monthly and the quarter
following the submission of the Exceedance Notice for wells that are being accelerated from
.semiannually to quarterly. Per teleconferences with UDEQ, Denison will propo.sed modified
language for the GWDP, Part l.G.l to document the accelerated reporting and monitoring
agreements resulting from the April 5, 2012 teleconference.
2.0 Exceedances in Semiannual Sampling Wells Accelerated to Quarterly
2.1 Semi-annual Wells with Two Successive Exceedances
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As indicated in the attached Table 1, the analytes discussed below exceeded their respective
GWCLs for two successive sampling penods (Q4 [2011] and Ql [2012]).
MW-3
Selenium has exceeded the GWCL for both the Q4 sampling event and the Ql sampling
event. The consecutive selenium exceedances noted in MW-3 were previously discussed
in the Plan and Time Schedule Under Part I.G.4 (d). submitted to UDEQ on June 13,
2011 as revised on April 13, 2012. An additional plan or schedule to address the Ql
exceedances is not necessary and is not being submitted because the assessment
processes and schedule have not changed since the June 13, 2011 and Apnl 13, 2012
submissions.
Fluoride has exceeded the GWCL for both the Q4 sampling event and the Ql sampling
event. The consecutive selenium exceedances noted in MW-3 were previously discussed
in the Plan and Time Schedule Under Part I.G.4 (d), submitted to UDEQ on June 13,
2011 as revised on April 13, 2012. An additional plan or schedule to address the Ql
exceedances is not necessary and is not being submitted because the assessment
processes and schedule have not changed since the June 13, 2011 and April 13, 2012
subnnssions.
MW-12
Selenium has exceeded the GWCL for both the Q4 sampling event and the Ql sampling
event. The consecutive selenium exceedances noted in MW-12 were previously drscussed
in the Plan and Time Schedule Under Part I.G.4 (d), subnntted to UDEQ on June 13,
2011 as revised on April 13, 2012. An additional plan or schedule to address the Ql
exceedances is not necessary and is not being submitted because the assessment
processes and schedule have not changed since the June 13, 2011 and April 13, 2012
submissions.
MW-18
Thallium has exceeded the GWCL for both the Q4 sampling event and the Ql sampling
event. The consecutive thallium exceedances noted in MW-18 were previously discussed
in the Plan and Time Schedule Under Part I.G.4 (d), submitted to UDEQ on June 13,
2011 as revised on April 13, 2012. An additional plan or schedule to address the Ql
exceedances is not necessary and is not being submitted because the as.sessment
processes and schedule have not changed since the June 13, 2011 and April 13, 2012
submissions.
TDS has exceeded the GWCL for both the Q4 sampling event and the Ql sampling
event. The consecutive TDS exceedances noted in MW-18 were previously discussed in
the Plan and Time Schedule Under Part I.G.4 (d), submitted to UDEQ on June 13, 2011
as revised on April 13, 2012. An additional plan or schedule to address the Ql
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exceedances is not necessary and is not being submitted because the assessment
processes and schedule have not changed since the June 13, 2011 and April 13, 2012
submissions.
MW-19
Nitrate + Nitrite have exceeded the GWCL for both the Q4 sampling event and the Ql
sampling event and during previous quarters. As mentioned above, nitrate + nitrite
concentrations are currently under re-evaluation, and a plan to address this consecutive
exceedance is not necessary and is not being subnntted.
MW-24
Field pH has been slightly outside (slightly lower than) the GWCL for both the Q4
sampling event and the Ql sampling event. As mentioned above, site-wide pH issues and
trends are currently under re-evaluation, and a plan and schedule to address this
consecutive exceedance is not necessary and is not being submitted.
MW-27
Nitrate -I- Nitnte have exceeded the GWCL for both the Q4 sampling event and the Ql
sampling event and during previous quarters. As mentioned above, nitrate + nitrite
concentrations are currently under re-evaluation, and a plan to address this consecutive
exceedance is not necessary and is not being subnntted.
Chloride has exceeded the GWCL for both the Q4 sampling event and the Ql sampling
event and during previous quarters. As mentioned above, chloride concentrations are
currently under re-evaluation, and a plan to address this consecutive exceedance is not
necessary and is not being submitted.
TDS has exceeded the GWCL for both the Q4 sampling event and the Ql sampling
event. The consecutive TDS exceedances noted in MW-27 were previously discussed in
the Plan and Time Schedule Under Part I.G.4 f J), submitted to UDEQ on June 13, 2011
as revised on Apnl 13, 2012. An additional plan or schedule to address the Ql
exceedances is not necessary and is not being subnntted because the assessment
processes and schedule have not changed since the June 13, 2011 and April 13, 2012
submissions.
MW-28
Chloride has exceeded the GWCL for both the Q4 sampling event and the Ql sampling
event and during previous quarters. As mentioned above, chloride concentrations are
currently under re-evaluation, and a plan to address this consecutive exceedance is not
necessary and is not being subnntted.
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2.1 Semi-annual Wells with New Exceedances Reported in Ql
There were no new exceedances for the senn-annual well samplmg program.
Denison respectfully requests UDEQ's concurrence with the addition ofthe TDS assessment in
MW-31 to the previously submitted Plan and Time Schedule subnntted June 13, 2011 as
amended April 13, 2012.
If you have any questions or require any further information, please contact the undersigned
Yours tpii/y.
JoTischler
Director, Compliance and Pennittmg
David Fr>denlund
Ron Hochstein
Harold Roberts
David Turk
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