DRC-2011-007201 - 0901a0688025d48a

StateofUtah
GARY R. HERBERT
Governor
GREG BELL
Lieutenant Governor
Departmentof
Environmental Quality
Amanda Smith
Executive Director
DIVISION OF RADIATION CONTROL
Rusty Lundberg
Director
2011-007
August 11,2011
CERTIFIED MAIL
(Return Receipt Requested)
Jo Ann Tischler, Director, Gompliance and Permitting
Denison Mines (USA) Corp.
1050 17^ Street, Suite 950
Denver, CO 80265
Subject: Nitrate Investigation Revised Phase 2 to 5 Work Plan Rev. 1.0, White Mesa Mill Site,
dated August 4, 2011: DRC Review Comments
Dear Ms. Tischler:
DRC review comments regarding the June 3, 2011 Denison Mines (USA) Corporation (DUSA) "Nitrate
Investigation Revised Phases 2 through 5 Work Plan Rev. 1.0" are enclosed (via URS Memorandum).
Ifyou have questions or concems regarding the comments, or would like to arrange a meeting or
teleconference to discuss the cornments, please contact me at [phone]. Thank you.
Sincerely,
Thomas Rushing, P.G.
Geotechnical Services Section
Enclosure: URS Memorandum
F:\DUSA\Nitrate Contamination InvestigationVPhase 2-5 WP Rev. I.OVDRC Comments Phase 2-5 Workplan Rev I Cover Ltr.doc
195 North 1950 West • Salt Lake City, UT
Mailing Address: P.O. Box 144850 - Salt Uke City, UT 84114-4850
Telephone [phone] • Fax [phone] • T.D.D. [phone]
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URS
MEMORANDUM
To: Tom Rushing (DRC), Loren Morton (DRC), Phil Goble (DRC)
From: Paul Bitter (URS), Jeremy Cox (URS)
cc: Robert Baird (URS)
Date: 11 August 2011
Re: Comments bn the Nitrate Investigation Phase 2-5 Work Plan, Rev 1.0, for White
Mesa Mill Site dated August 4, 2011.
TIris memorandum contains the co?nments by URS and the Utah Depamwnt ofEnvironmental
QualitxK Division ofRadiation Control (DRC) on the Phase 2-5 WorkPh^^^
Nitrate Investigation at the White Mesa Mill Site. The Work Plan was prepared by Denison
Mines USA (DUSA) and was dated August 4, 2011. Comments have been provided by URS as a
deliverable for Contract No. 116259 issued through the DRC. This review also is in accordance
with the amended Memorandum of Understanding (MOU) between the DRC and DUSA dated
May 19, 2011. For purposes of expediency, the URS and DRC comments are edited for
conciseness and combined into one memo. Note that format, gramfnar, and punctuation in the
Work Plan M^ere not revicM^ed for accuracy and consistency.
The comments regarding the Phase 2-5 Work Plan, Rev 1.0, are presented below. Please note
that, per the June 30, 2011 Revised Tolling Agreement (Rev. 2), all DRC / URS comments must
be addressed and resolved, and the revised Phase 2-5 Work Plan Rev 1.0 must be submitted, on or
before August 18,2011.
1. General Comment: Most of the DRC/URS comments on the previous submittal of this
document have been adequately addressed. The comments listed below concem some ofthe
previous comments that may not have been adequately addressed, or comments related to
revised material in the document that was not previously review^ed by DRC and URS.
2. Section 2.3.3.1: The emphasis on the potential effect of the Mancos Shale paleoridge in the
"known conditions" sections for multiple potential or possible source areas does not appear to
correspond with the conclusions regarding the effects of the slope and thickness of the
Mancos Shale in Section 2.3. In Section 2.3, based on the demonstrated transport of
chloroform away from the presumed source areas at the site, DUSA concludes that "Mancos
Shale surface topolog>^ and/or thickness may or may not exert a significant influence on
seepage from potential nitrate sources.'' Please revise the text regarding the potential effects
of the Mancos Shale paleoridge accordingly in the "known conditions" subsections within
Section 2.3.3.1.
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3. Sectipn 2.3.3.1: The text in the "decision process" subsections regarding the criteria for
Phase 3 sampling appears to differ from the language used in Section 3.3.1. In Section 3.3.1,
the criterion for Phase 3 sampling is presented as twice the background level, wihich is
defmed as the 95% UCL of data collected in Phase lA. In Section 2.3.3.1, the criterion is
presented as "above background". DRC recommends use of the language from Section 3.3
throughout Section 2.3.3.1 or insertion of references to Section 3.3 to explain the criterion.
4. Section 2.3.3.1: The text in tlie "decision process" subsections suggests that "archived"
samples could be utilized for Phases 4 and 5. Groundw-ater samples or soil/bedrock samples
may not be archived for any period that would violate sample preser\^ation and / or holding
times for the analyses. Please specify sample preservation and holding time requirements for
both types of samples. In addition, it is not clear which groundw'ater or soil samples might be
archived. Please specify the process for archiving the samples in the appropriate subsections
in Section 3. Assuming that archiving samples does not result in a violation of sample
preser\'ation or holding times, the samples must be stored under proper chain of custody
controls in a secure location that is both cool and dark, such as a refrigerator or freezer:
5. Section 3.2.4.2: The method for perchlorate analysis was specified as Method 6850 in the
Final Phase 2 Work Plan dated July 12, 2011. Please revise the method number accordingly
in Section 3.2.4.2.
6. Section 3.3.1: The preliminary data from Phases 1A and IB are now^ available, which
enables selection of the sampling locations in Phases 3 A and 3B. Please indicate the specific
sampling locations for Phases 3 A and 3B in this Work Plan. Proper selection of the number
and locations of the deep borings cannot be detemiined until after resolution of DRC
concems / open issues with the Phase 1 results DUSA provided on August 4, 2011 (email).
Some of these concems w^ere briefly discussed with DUSA in a conference call on August 11,
2011. With regards to the Phase 1 submittal, please resolve the following open issues:
a. Provide copies of all laboratory reports (including EDD format) for the soil
sample analysis from all phases of Phase 1.
b. Describe and justify derivation ofthe statistics used to calculate: "background"
soil concentrations, the Upper Confidence Levels (UCLs), and the selection of a
2-times UCL value.
c. Describe and justify all assumptions and calculations used in the Table 1 mass
balance calculations in the August 1, 2011 Intera memo. Provide evidence, or cite
references w^here written evidence is found to support all assumptions. Please
demonstrate why the assumptions and calculations are representative of actual
conditions experienced on White Mesa and during mill site operations, both
historic and modem. In the event that evidence is not available to support the
assumptions / calculations, please describe and justify why they are conservative
for purposes of protection of the environment.
7. With regards to Phase 3B, and as an altemative to the description / justification requested in
Item 6, above, DUSA may opt to drill deep bedrock borings to the water table at each surface
source location investigated in Phase IB. Under this option, please ensure that the deep
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bedrock boring is co-located with the Phase IB geoprobe boring site that shows the highest
ammonia (N) and nitrate/nitrite (N) inventor}^ in the soil profile.
8. For all deep bedrock borings drilled, please ensure the depth of each extends to the upper
geologic contact of the Bmshy Basin Member of the Morrison Fonnation. We also
recommend that upon completion of each boring, that a permanent monitoring W'cll be
installed. Be advised that the number and location of groundw-ater monitoring w^ells that
might be required will be determined after DRC review of the bedrock core sample analysis
(laborator}') results from the Phase 3 effort.
9. Please provide deadlines by which draft results will be provided to the DRC for Phases, 2, 3,
4, and 5.
10. Sections 3.4 and 3.5: No plan is described for how stable isotope compositions will be
evaluated in Phase 4 and 5. Criteria must be provided in the W'ork plan for determining
whether nitrate is representative of natural or anthropogenic sources.
11. Sections 3.4 and 3.5: It is not possible to fully evaluate these sections without the updated
QAP, which is to be completed at a future date. Please provide the QAPs with the DUSA
Phase 2-5 Workplan revision due on or before August 18,2011..
12. Section 3.4, second paragraph, 1st sentence: "The stable isotopic composition of nitrogen,
ox}'gen (NO3, NH4) and sulfur (SO4) will be measured..." should be corrected to be
consistent with later statements: "The stable isotopic composition of nitrogen (NO3, NH4),
oxygen (NO3, SO4) and sulfur (SO4) will be measured..." Please include the oxygen
istotopes.
13. Section 3.4: Oxygen and hydrogen stable isotope compositions of w-ater should be measured
as originally proposed. These data are critical for evaluating the oxygen isotopes'
compositions of sulfate and nitrate, and for determining mixing betw'cen surface water and
groundwater sources. Please revise the wwk plan accordingly.
14. Section 3.4, first numbered item: Method 300.0 is proposed for analysis of ammonia.
Method 350.2 was previously recommended for ammonia analysis for groundw-ater or
wastewater samples in the DRC/URS comment #34 in die March 2011 comments on the
initial Work Plan. Please review the selected analytical method for ammonia in these
matrices and revise the Phase 4/5 Work Plan as appropriate. Be aw^are that the detection
limits of any niethod must meet data quality objectives (DQOs). The method detection limits
and DQOs and must be included in the Phase 4 and 5 QAPs.
15. Section 3.4, second to last paragraph: "First the 8^^0 of both sulfate and nitrate molecules
will be analyzed, because the exchange of oxygen isotopes in these molecules occurs in both
atmospheric and aqueous environments."
The use ofthe word "exchange" is not an accurate description here. The oxygen isotopes in
nitrate are only exchangeable at low pH values not typically encountered in groundw'ater
systems. Oxygen isotopes are, however, inherited from an atmospheric (O2) and/or aqueous
(H2O) environment, which reflect their source. For example, nitrate formed by nitrification
of ammonium typically inherits ox>^gen from the atmosphere and from water in the
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environment w^here nitrification occurs. The oxygen isotope composition of nitrate formed
by nitrification, therefore represents a mix (typically in a 1:2, 02:H20 ratio) of oxygen from
this environment. Nitric acid only contains oxj^gen from the atmosphere, and therefore has a
much different ox\^gen isotope signature. Please revise the w^orkplan to describe how^ these
phenomenon / processes will be considered during review / evaluation ofthe data from
Phases 4 and 5.
16. Section 3.5, last paragraph: The proposed submittal date for the Phase 5 QAP (June 29,
2012) is unacceptably protracted and does not correspond to the submittal date of
November/December 2011 show^n in the June 2011 Revised Phase 2-5 Work, Plan. Further,
during past meetings and an August 3, 2011 meeting with DRC and DUSA management, the
Executive Secretary provided his expectation that: 1) all DUSA fieldwwk for Phases 2 - 5
will be completed on or before December 31, 20II, and 2) the DUSA fmal revised
Contaniination Investigation Report (CIR) for all phases of tlie Nitrite Investigation be
submitted for review and approval on or before June 1, 2012. Please revise the Phase 2-5
Workplan / schedule accordingly or justify^ W'hy additional delays are necessary.
••.•'••./••.
17. Figure 18: This figure may mistakenly refer to Phase 5 sampling instead of Phase 4
groundw-ater sampling. Please update the label as appropriate. In addition, this figure
indicates that isotopic sampling for groundw-ater wnould occur, only if fingerprints for
agricultural or military activities are detected during Phase 2. This approach is not consistent
with the weight of evidence approach requested by DRC in reviews of previously submitted
documents, see DRC comments dated March 21, 2011 and June 23, 2011. In addition, the
decision logic in Figure 17 suggests that isotopic fingerprints collected from soil at potential
source areas will be compared to the Phase 4 isotopic fingerprints in groundwater. If Phase 4
is not conducted, a comparison of isotopic fingerprints between the potential sources and the
groundwater, as indicated by Figure 17, wnould not be possible. DRC requests that logic in
Figure 18 be revised to indicate that, although the Phase 4 sampling would occur at a later
time than Phase 2, the results of both Phase 2 and Phase 4 are evaluated jointly (i.e., in
parallel, not in series) in a weight of evidence approach.
18. Table 1: The proposed schedule with an end point (June 2013) in unacceptably protracted
and is inconsistent with schedules previously discussed by DRC arid DUSA management, see
comment 16 above. Please revise the table according to discussed timelines, as outiined in
comment 16 above, or justify w^hy additional delays are necessary.
[End of comments]
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G^RTIFIED- lyiAIL- RECEIPT
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Return Receipt Fee (Endorsement Reauirem
Here
ndorsement Reauired^
RE: 8/11/11; Nitrate phase 2 to 5 rev 1 / TR
Jo Ann Tischler
Denison l\/lines (USA) Corp
1050 Seventeenth ST, STt ^
Denver, Co 80265