DRC-2011-007737 - 0901a0688029acc4

State of Utah
GARY R. HERBERT
Governor
GREG BELL
Lii'iitenant Governor
Department of ^
Environmental Quality
Amanda Smitii
Execuiivc Director
DIVLSiON OF RADIATION CONTROL
Rusty Lundberg
Direclor
MEMORANDUM
TO: Fiie
THROUGH: Phil Goble, Compliance Section Manager f/l^
''f
FROM: Tom Rushmg, P.G. {l/l^/ll
DATE: November 17, 2011
SUBJECT: Denison Mines (USA) Corp. Transmittals Dated June 13, 2011: June 30, 2011;
September 7, 2011, and; August 8, 2011 Regarding Groundwater Compliance
Limit Exceedences
Review Summary:
This memo details the DRC review of several Denison Mines (USA) Corp. (DUSA) submitted
documents, these include:
1. DUSA, June 13, 2011, Proposed Correction of Groundwater Control Limits
("GWCL's"forpH.
2. DUSA, June 13, 2011, Transmittal of Plan and Time Schedule under Utah Ground
Water Discharge Permit UGW370004 Part I.G.4(d)White Mesa Uranium Mill;
Includes an attached document dated June 13, 2011 and titled State of Utah Ground
Water Discharge Permit UGW370004 Plan and Time Schedule Under Part I.G.4(d)
for Violations of Part I.G.2 for Constituents in the First, Second, Third and Fourth
Quarters of 2010 and First Quarter of 2011
3. DUSA, June 30, 2011, Request for Extension of Submittal Date for Report on Proposed
Correction of Groundwater Compliance Limits (GWCL's) for pH
4. DUSA, August 8, 2011, State of Utah Ground Water Discharge Permit No.
UGW370004 White Mesa Uranium Mill - Notice Pursuant to Part l.G.1(a)
5. DUSA, September 7, 2011, Transmittal of Plan and Time Schedule under Utah Ground
Water Discharge Permit UGW370004 Part I.G.4(d) White Mesa Mill
6. DUSA, November 3, 2011, State of Utah Ground Water Discharge Permit No.
UGW370004 White Mesa Uranium Mill - Notice Pursuant to Part l.Gl(a)
Note that the documents are inter-related and are based on conditions relating to out of
compliance status (OOC) due to exceedences of Groundwater Compliance Limits for specific
105 North 1050 West • Salt Lake CitV: UT
Mailing Address: P.O. Box 144850 • Salt Lake City, UT 84114-4850
Telephone (801) 5,^6-4250 • Fax [phone] - T.D.D. [phone]
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DUSA June 13, 2011 Plan and Time Schedule
DRC Review Memo
Page 2
parameters which are listed in the facility Utah Ground Water Discharge Permit, Permit No. UGW
370004 (Groundwater Permit). The flow chart below summarizes how the documents are
inteiTclated:
February 1,2011 DUSA
Proposed Submittal Date
Revised GWCL's for pH,
Report to be submitted end of
2"^ Qtr, 2011
DRC Notice of Violation, Docket No.
UGWl 1-02, Issued May 9, 2011
June 13, 2011 Plan and Time Schedule for
violations cited in UGWl 1-02, violations
pertinent to Groundwater Monitoring Reports
for the V\ 2nd, 3'"^ and 4"" quarters of 2010;
the Plan and time schedule also includes
actions for additional GWCL exceedences in
the 1^' quarter of 2011 Groundwater
Monitoring Report.
September 7, 20f 1 Plan and Time Schedule
for violations cited in the 2"^^ quarter 2011
Groundwater Monitoring Report (Note that all
previous GWCL exceedences which were not
removed from accelerated monitoring status
are carried forward from the June 13, 2011
(Plan and Time Schedule)
February 14, 2011 DRC E-mail
agrees with DUSA timeline for
submittal of report.
June 20, 2011 DUSA Request
for Extension of the Submittal
Date for a report on Proposed
Correction or GWCL's for pH
August 8, 2011 DUSA
Notice of GWCL
Exeedences for the 2"^*
Quarter 2011 Groundwater
Monitoring Report
November3, 2011 DUSA
Notice of GWPL
Exceedences for the 3^'^
Quaiter 2011 Groundwater
Monitoring Report
Note that several of the consecutive exceedences of GWCL's (OOC status) addressed in the above
reports were cited in a DRC Notice of Violation and Order, Docket UGWl 1-02 (NOV) for failure
by DUSA to provide a source assessment report as required by the Groundwater Permit Part
I.G.4(c). Part E. ofthe NOV required the submission of 3 responses which included:
DUSA June 13, 2011 Plan and Time Schedule
DRC Review Memo
Page 3
1. Part E.2 of the NOV required the submission of a ''report with revised statistics for Field
pH, which will be used for revised GWCLs. This report shall be submitted for Executive
Secretary approval on or before June 30, 2011. This report shall include at a minimum:
• Revised statistics to be used to revise the Permit Field pH GWCLs must be based on
the Decision Tree/Flowchart was conditionally approved by the DRC on August 24,
2007. This same Decision Tree/Flowchart was used by DUSA to calculate the
proposed GWCLs for the background groundwater quality reports dated October 2007
and April 30, 2008,
• A Complete source assessment ofthe contaniination in wells with decreasing pH
trends,
• Evaluation of the physical extent and dispersion of the contamination, cmd
• Evaluation of possible remedial action options to restore and maintain groundwater
quality at the POC wells in question. "
2. Part E.3. of the NOV required ''the submission of "a report to the Co-Executive Secretary
within 30 calendar days of receipt ofthis NOV and Order to include but not be limited to
the following items:
a. The root cause ofthe noncompliance,
b. Corrective steps taken or to be taken to prevent re-occurrence ofthe noncompliance,
c. Date when compliance was/or will be achieved.'"'
3. Part E.4. of the NOV required DUSA to "Prepare and submit within 30 calendar days of,
receipt of this NOV and Order, a written plan and time schedule, for Executive Secretary
approval, to fully comply with the requirements of Part l.G.4(c) ofthe Permit, including,
but not limited to:
a. Submittal ofa written assessnient ofthe source(s) of the six contaminants and multiple
wells listed in Table 3, above; including: cadmium, manganese, selenium, thallium,
uranium, and total dissolved solids.
b. Submittal of a written evaluation ofthe extent and potential dispersion of said
groundwater contamination.
Submittal ofa written evaluation ofany and all potential remedial action to restore and
' maintain ground water quality at the facility, for the POC wells and contaminants in
question, to ensure that: 1) shallow groundwater quality at the facility will be restored
cmd 2) the contaminant concentrations in said POC wells will be returned to and
maintained in compliance with their respective GWCLs."
Item # 3 above was received by DRC on June 13, 2011 and was used to review the violations and
calculate a monetary penalty related to standing violations. Note that all issues related to this
DUSA June 13, 2011 Plan and Time Schedule
DRC Review Memo
Page 4
response were closed out by DRC letter on October 26, 2011 and therefore this document was
previously reviewed and is not ongoing.
Per Item # 2 above, the required report was not submitted and to date DRC has not received
revised statistics or an evaluation of the extent of the contamination. Per the June 30, 2011 DUSA
letter, DUSA found that the decreasing pH trends are a "site wide phenomenon" ...which "render
the Logic Flow Diagram inappropriate for setting GWCL's for pH at the site." In lieu of revised
statistics, DUSA requested DRC acceptance of additional studies related to the decreasing pH
trends which are included in the DUSA June 13, 2011 letter. DUSA has requested a meeting with
DRC to discuss and agree on a path forward.
Per Item # 4 above, DUSA has provided the "Plan and Time Schedule" documents which are
referenced above and are the subject of this review. Recommendations related to follow up
actions regarding the decreasing pH trends at the site and groundwater contaminants in OOC
status at the White Mesa Uranium Mill follow.
Nitrate (and Chloride) Contamination Plume
The DUSA submissions note that Nitrate + Nitrite (as N), as well as Chloride concentrations in
the Mill groundwater are a subject of ongoing investigation and that DUSA is cuiTently in the
process of preparing a corrective action plan to address the exceedences of the associated
GWCL's.
DRC concurs that the current monitoring wells (MW wells) which are in OOC for Nitrate +
Nitrite (as N) and also for chloride are within the currently delineated nitrate plume and are part of
the nitrate contamination project. These include well numbers MW-26, MW-27, MW-30, and
MW-31.
DRC also notes that well MW-28 which is in OOC for chloride is within the delineated plume for
chloride as part of the nitrate contamination investigation. Therefore, it is agreed that these wells
and parameters are currently included with the nitrate contamination project and do not need to be
evaluated as part of the OOC study.
DUSA Recommended Actions for Studies Related to the Decreasing pH Trends
MW-3, MW-3A, MW-5, MW-11, MW-18, MW-27, MW-30, MW-31 - Pre-existing Rising
Trends
The June 13, 2011 DUSA letter states that rising trends noted in the applicable well set (above)
have been explained as natural rising background in the current background groundwater quality
report, cited below:
DUSA June 13, 2011 Plan and Time Schedule
DRC Review Memo
Page 5
A Revised Background Groundwater Quality Report: Existing Wells for Denison Mines (USA)
Corp. 's Mill Site, San Juan County Utah, October 2007, prepared by INTERA Inc. (INTERA
2007)
DUSA states that per the report conclusions there are increasing and decreasing trends in
constituents in upgradient and far downgradient, and Mill site wells, "which provide evidence that
there are natural forces at work that are impacting groundwater quality across the entire site."
Denison cites this reference to indicate a natural source for the concentration trends.
Additionally, DUSA cites the University of Utah Study at the White Mesa Mill:
Summary of Work Completed, Data Results, Interpretations and Recommendations for the July
2007 Sampling Event at the Denison Mines, USA, White Mesa Uranium Mill Near Blanding,
Utah, Prepared by T. Grant Hurst and D. Kip Solomon, Department of Geology and Geophysics,
University of Utah, May, 2008
Specifically DUSA points to the conclusions of the Study which states "Stable isotope
fingerprints do not suggest contaniination of groundwater by tcdlings cell leakage, evidence that is
corroborated by trace metal concentrations similar to historically obser\'ed concentrations."
For the applicable set of wells, DUSA recommends a "re-evaluation" of the concentration trends
to include:
1- Geochemical Analysis
2- Mass Balance Analysis
3- Hydrogeologic analysis for wells distant from the Mill's tailings cells
The purpose of these studies would be to "evaluate the behavior ofall the constituents in the well
in question to determine if there are any changes in the behavior" of applicable constituents as
compared with the past studies.
If significant changes are identified then DUSA would propose to the Executive Secretary further
.analysis to identify the source and the extent of the contamination.
If no significant changes are identified then DUSA would propose changes to the GWCL's for the
wells and constituents of concem.
DRC Comments:
DRC agrees with the concept of using geochemical analysis and groundwater transport velocities
to analyze the source of the OOC parameters. DRC notes that for consistency with the University
of Utah Study, and in order to re-validate that the tailings cells are not the source of GWCL
exceedences, further analysis is prescribed. Consistent with the cited University of Utah Study,
DRC recommends that DUSA perform monitonng and an analysis of sulfur isotope ratios
DUSA June 13, 2011 Plan and Time Schedule
DRC Review Memo
Page 6
(isotopic fingeiprints) in the affected groundwater monitoring wells. The results could then be
compared to the isotopic fingerprints results obtained by the University of Utah study for the
tailings cells.
If DUSA elects to include stable isotope analysis as a tool to evaluate the tailings cells as a
potential source then a protocol for quality assurance (sample collection and analysis) would need
to be submitted for review and approval by the Co-Executive Secretary. DRC is aware that
DUSA was coordinating the collection of groundwater samples for the analysis of stable isotopes
per a source assessment study for the nitrate plume beneath the White Mesa Mill. DRC
anticipates that much of the coordination which was being undertaken for that study could be
utilized for this investigation.
DRC notes that in relation to the statistical evaluation tools which would be used to re-calculate
background concentration, DUSA has cited EPA guidance (EPA 530/R-09-007, March 2009,
Statistical Analysis of Groundwater Monitoring Data at RCRA Facilities Un ified Guidance,
Environmental Protection Agency, Office of Resource Conservation and Recovery). DRC is
concemed that in sections of the proposal DUSA refers to the use of intra-well statistics and in
particular the use of control chart tests to test normality of the data set, although it is not clearly
stated if these statistical techniques are proposed.
Specific to the White Mesa Facility, DRC expectation is that the statistical evaluation will be
consistent with the logic flow diagram included in the background study reports (INTERA 2007).
DRC has noted that per the DUSA June 30, 2011 correspondence it is indicated that in the case of
pH trends at the White Mesa site, the use of the logic flow diagram is inappropriate based on
"associated site-wide phenomena" however, DRC notes that no additional justification was
submitted to explain the failed statistical evaluation of the analyzed wells.
MW-26 - Pumping Well
The June 13, 2011 DUSA letter proposes certain actions for monitoring well MW-26 which is
currently being utilized as a pumping well for active remediation of the chloroform plume and
which is in OOC status for the following parameters:
Nitrate + Nitrite (as N), Uranium, Chloroform, Chloride, Field pH, Dichloromethane (Methylene
Chloride), TDS and Adjusted Gross Alpha
DUSA points out in the June 13, 2011 letter that variation in constituents (geochemical
parameters) in a pumping well is expected. DUSA also states that this determination was agreed
upon by the Go-Executive Secretary in a September 2009 Statement of Basis. DUSA proposes the
following activities in relation to the OOC status at MW-26:
1- Geochemical Analysis
2- Mass Balance Analysis
DUSA June 13, 2011 Plan and Time Schedule
DRC Review Memo
Page 7
The overall objective ofthe study will be to identify "if significant changes are identified in the
Source Assessment Report that cannot be attributed to the pumping itself or to background
influences." If such evidence is found then DUSA proposes that further study will be initiated as
agreed to by the Co-Executive Secretary. DUSA will also evaluate whether additional remedial
actions may be appropriate.
DRC Comments
DRC notes that per DUSA quotation of the Existing Wells Background Report prepared by
INTERA, "In fact, the pumping wells are having the effect of drawing down water levels in other
wells (see for example Figure 2 of Appendix D of the second quarter 2011 (Chloroform
Monitoring report)." DRC does note that if the impact of drawdown were occurring on a
widespread basis it could have the effect of significant changes in the groundwater geochemistry,
due to pore volumes being oxygenated as a result of drawdown. Per DRC review of the 2007
Chloroform Monitoring Report, as well as recent groundwater monitoring reports, it appears that
the pumping cone of depression radius is approx 1,000 ft. Another potential impact of the
pumping could be to draw oxygenated water from other regions (e.g. groundwater from the
wildlife pond groundwater mound) southward due to the changes in hydraulic gradients (radial
flow).
Per Section 4.2.2. of the June 13, 2011 DUSA letter. Constituents in Pumping Wells, DUSA
agrees that the pumping process makes the monitoring of compliance standards in the pumping
well impossible and complicates compliance monitoring for any other monitoring wells within the
vicinity of pumping wells. Therefore, as part of the study DUSA is required to evaluate: 1. Other
remediation strategies for the chloroform plume to avoid geochemical impacts due to oxygenation
of the groundwater, and 2. Recommend other actions to minimize the impacts.'
MW-3, MW-3A, MW-5, MW-11, MW-18, MW-30 - Decreasing pH Trends
DUSA proposes a separate line of study for groundwater monitoring wells which, DUSA feels,
are being impacted by decreasing trends in pH.
1- Geochemical Analysis
2- Mass Balance
3- Hyrogeologic analysis for wells distant from the Mill's tailings cells
Per the DUSA June 13, 2011 letter, the purpose of the studies would be to:
Geochemiccd Analysis: Study to evaluate "indicator constituents" to determine changes in
behavior for each well since the date of the Existing Wells Background Report.
DRC notes that lining the wildlife ponds with impermeable barrier materials would reduce or eliminate the artificial
surtace water recharge from that source. By denying the artificial recharge from the wildlife ponds; the underlying
groundwater mounds would be reduced in size, reduce oxygenation of the groundwater, groundwater flow would
return to ifs normal pathways, and the aquifer would eventually return to equilibriuin.
DUSA June 13, 2011 Plan and Time Schedule
DRC Review Memo
Page 8
Mass Balance Analysis: Evaluation of concentration in the groundwater in comparison with the
Mill tailings and an evaluation of any mounding at the location of the well in question.
Hydrogeologic Analysis: Evaluation to determine the plausibility of impact from Mill tailings.
In the June 13, 2011 letter, DUSA refers to a letter dated February 1, 2011 which was submitted to
propose revision of GWCL for pH in the Groundwater Permit- Per DRC review of that letter it
was noted that DUSA proposed to submit revised GWCL's for "all on-site wells utilizing "the pH
data developed from the time of initiation of the GWDP and its associated Quality Assurance Plan
in 2005 to the present." Additionally, the February 1, 2011 letter proposed that the revised
GWCL's would be generated according to "the process flow diagram in Figure 17 of the
Background Study Report, including box and whisker plots, statistical distribution analyses, and
trend analyses." This revision to the pH GWPL's was based on DUSA's concem that the existing
GWPL's were based on data generated at the contract laboratory and not from field data. DUSA
additionally quotes the EPA 1986 Technical Enforcement Guidance Document for RCRA
groundwater monitoring to support the re-evaluation.
DRC notes that the results of that evaluation were never submitted to DRC, but does note that
additional conespondence occurred regarding the evaluation and that in the June 30, 2011 letter
DUSA states that, "Denison completed this evaluation in anticipation of providing a report
including revised GWCUs by June 30, 2011, a date proposed by Denison in the February 1, 2011
letter...Following the statistical evaluation of pH data by Denison 's geochemical consultant,
INTERA, 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
ofthe June 2011 groundwater results, and many of the other results froni the second quarter,
were already outside the revised GWCL's to be proposed...It appears that this .site-wide
phenomenon of decreasing pH trends may render the Logic Flow Diagram inappropriate for
setting GWCL's forpH at the site. "
The DUSA June 30, 2011 letter goes on to discuss the "revised" root cause of the pH
exceedences, since it was shown that re-evaluation of background values based on field pH did
not resolve the issue. Denison proposed that the root cause is the dissolution of pyrite in the
formation mineralogy surrounding the affected monitoring well screened intervals, and states that
the groundwater in contact with pyrite has been oxygenated by "surging, bailing, and over-
pumping for redevelopment, ongoing pumping during routine monitoring, (and, for some wells,
more frequent pumping stresses due to accelerated monitoring). The June 30, 2011 letter also
states that chlorofonn pumping wells have been subjected to the additional stresses of on-and off
pumping cycles for chloroform capture pumping. Denison also states that effects of drought,
regional recharge water pH, and field instrumentation are being evaluated as potential contributors
to the pH depression phenomenon.
DUSA June 13, 2011 Plan and Time Schedule
DRC Review Memo
Page 9 ,
DRC Comments
DRC agrees with the concept of performing a geochemical analysis of the wells with decreasing -
pH trends, as well as an evaluation of mass balance and groundwater transport velocities. Ifthe
pH trends are due to oxygenation of pyrite, then there should be corresponding changes in the
dissolved concentrations of other elements (e.g. sulfate). Also, if a local oxygen source such as
that due to well developments is suspected to be the cause of dissolution of pyrite, then it would
be expected that a limited amount of pyrite would be available for dissolution and that once
consumed, the pH levels should readjust. The analysis is required to include an evaluation of the
amount of pyrite available for dissolution based on, 1. The aquifer mineralogy, and, 2. The
potential sources and mechanisms of oxygen introduction into the aquifer mineralogy.
DRC notes that an evaluation of chemical speciation utilizing a geochemical model, e.g.
PHREEQC would provide additional support to any arguments made related to the DUSA
geochemical analysis.
Any conclusions made regarding a natural source of the pH exceedences must be supported with
solid geochemical and physical evidence.
DUSA Proposed Deliverable - Source Assessment Report
DUSA proposes that based on the outcome of the above additional study a "Source Assessment
Report" will be prepared and submitted to the Co-Executive Secretary within 60 days after the
approval of the June 13, 2011 letter (Plan).
DUSA states that the "Source Assessment Report will detail the results ofall ofthe cuialysis to be
perfonned and the conclusions to be drawn from such cmalyses, including any proposed revisions
to existing GWCL's. The Source Assessment Report will also identify any further studies that the
ancdysis indicates should be performed, and will propose, for Executive Secretary review cmd
approval, a plan and schedule for completion of anv such additional studies. "
DRC Comments
In general DRC agrees with the study approach outlined by DUSA to evaluate the sources of the
parameters in OOC as outlined in the DUSA June 13, 2011 letter. The timeline for DUSA
submittal ofthe "Source Assessment Report" within 60 days of Co-Executive Approval of the
Plan, is reasonable.
Statistical Methods:
Per discussion above, DRC will require that any proposed revised GWCL is calculated in
accordance with the logic flow diagram included in the background study reports (INTERA
2007). DRC has not received adequate justification, or a clear proposal from DUSA regarding a
DUSA June 13, 2011 Plan and Time Schedule
DRC Review Memo
Page 10
deviation from that approved methodology. If DUSA insists on utilizing a different statistical
methodology then additional information must be submitted to DRC including:
1. A demonstration that the logic flow diagram is inappropriate including the failed statistical
evaluation using the logic flow diagram, and
2. A description of the proposed altemate statistical method including applicable documents and
references.
Remediation Pumping
Per discussion above DRC requires that DUSA provide as part of the "Source Assessment
Report," an evaluation of:
1. Altemate remediation strategies for chloroform, besides active groundwater withdrawal, to
avoid geochemical impacts due to oxygenation of the groundwater (as well as other impacts), and
2. Recommendations for other DUSA actions which could be implemented to minimize
geochemical impacts caused by groundwater pumping activities and the constant recharge of the
wildlife ponds.
Stable Isotope Monitoring
DRC recommends the addition of sulfur isotope ratios in groundwater be used as a tool to justify
(re-validate) that the tailings cells are not the source of the rising trends as discussed above.
DRC Conclusions
Based on the above review and findings related to plan and time schedule for assessment of the
sources for current parameters in OOC status, DRC will contact DUSA to discuss the study plan
and confirm a due date for submittal of the "Source Assessment Report."
DRC will prepare a letter of findings and a Confirmatory Action Letter to be sent to DUSA.
References
Denison Mines (USA) Corp (DUSA). February 1, 2011, Letter from Jo Ann Tischler to Rusty
Lundberg, Re: State of Utah GroundwcUer Discharge Pennit No. UGW370004 Proposed
Correction of Groundwater Control Limits for pH
DUSA, June 13, 2011, Transmittal of Plan and Time Schedule under Utah Ground Water
Discharge Pennit UGW370004 Part I.G.4(d)White Mesa Uranium Mill; Includes an attached
document dated June 13, 2011 and titled State of Utah Ground Water Discharge Permit
DUSA June 13, 2011 Plan and Time Schedule
DRC Review Memo
Page 11
UGW370004 Plan and Time Schedule Under Part I.G.4(d)for Violations of Part I.G.2for
Constituents in the First, Second, Third and Fourth Quarters of 2010 and First Quarter of 2011
DUSA, June 30, 2011, Request for Extension of Submittal Date for Report on Proposed
Correction of Groundwater Compliance Limits (GWCL's) for pH
DUSA, August 8, 2011, State of Utah Ground Water Discharge Permit No. UGW370004 White
Mesa Uranium Mill - Notice Pursuant to Part LG.l (a)
DUSA, September 7, 2011, Transmittal of Plan and Time Schedule under Utah Groimd Water
Discharge Permit UGW370004 Part I.G.4(d) White Mesa Mill
DUSA, November 3, 2011, State of Utah Ground Water Discharge Permit No. UGW370004 White
Mesa Uranium Mill - Notice Pursuant to Part l.G 1(a)
Utah Administrative Code, R317-6, Groundwater Quality Protection, January 23, 2007
Utah Ground Water Discharge Pennit, Pemiit No. UGW370004, Denison Mines (USA) Corp.
White Mesa Uranium Milling and Tailings Facility', July 14, 2011
Utah Water Quality Board, May 9, 2011, Notice of Violation and Compliance Order, Docket No
UGWl 1-02, In the Matter of Denison Mines (USA) Corp.