DRC-2010-002262 - 0901a0688016fa38

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DENISOtTi/i
MINES
Denison Mines (USA) Corp.
1050 17th Street, Suite 950
Denver, CO 80265
USA
Tel: [phone]
Fax:[phone]
www.denisonmines.com
VIA FEDERAL EXPRESS
March 3, 2010
Mr. Dane Finerfrock, Executive Secretary
Utah Radiation Control Board
Utah Department of Environmental Quality
168 North 1950 West
P.O.Box 144810
SaU Lake City, UT 84114-4810
Dear Mr. Finerfrock:
Re: Renewal Application for Radioactive Materials License (RML) No. UT1900479
Health Physics Interrogatories -- Round 3; and Engineering Comment Interrogatories -
Round 2
This letter is in response to the Executive Secretary's letter of December 28, 2009 addressed to
Denison Mines (USA) Corp. ("Denison" or "DUSA"), with attached Health Physics
Interrogatories - Round 3 and Engineering Comment Interrogatories - Round 2, pertaining to the
WhUe Mesa Mill's (the "Mill's") Febmary 2007 License Renewal Application (the "2007
License Renewal Application").
The following Attachments are included with this letter:
Attachment Description
A Index to Appendices in the 2007 License Renewal
Application revised to add Revision 4.0 of the Reclamation
Plan as Appendix P and the Cell 4A BAT Monitoring,
Operations and Maintenance Plan as Appendix Q; Tab Sheets
and Place Holder Sheets, stating the location of the new
Appendices P and Q
B Revised Figure No. A-2.2.4-1 of Revision 4.0 of the
Reclamation Plan
C Revised Figures A-5.1-1, -2, and -3 of Revision 4.0 of the
Reclamation Plan
D January 29, 2010, Technical Memorandum from MWH
Americas, Inc.
E Revised Figure 3.2.3-1 of Revision 4.0 of the Reclamation
Plan
Attachment Description
F Revised Forais Nos. F-23, -25, and -26 of Revision 4.0 ofthe
Reclamation Plan
G Schedule of Amendments to be Inserted at the Beginning of
Revision 4.0 of the Reclamation Plan (before the Table of
Contents), Indicating the Revisions made to Revision 4.0 of
the Reclamation Plan
Accompanying this letter is a package that contains two copies of each of the items in the
foregoing Attachments. Those copies are to be inserted directly into the two copies of Revision
4.0 of the Reclamation Plan or the 2007 License Renewal Application, as the case may be, that
have previously been provided to the Executive Secretary. In the case of Attachment G, the two
accompanying copies of the Schedule of Amendments are to be inserted at the front of each of
the two copies of Plan (prior to the Table of Contents). This will allow the copies contained in
the Attachments to remain a part of this letter.
Each Interrogatory is shown in italics below, followed by Denison's response to the question
and/or request for information.
1. SECTION 1, HEALTH PHYSICS INTEROGATORIES -ROUND 3
1.1 HEALTH PHYSICS ROUND 3 INTERROGATORY STATEMENT-Release Surveys:
Round One Interrogatory Statement 14-17 "Explain how the survey techniques, the release standards
used atid documentation of surveys of Equipment are sufficient to demonstrate regulatory compliance
and maintain public health and safety. Explain why surveying techniques such as the use of Large
Area Wipes and swipes to look for removable contamination are not being used on all items being
surveyed for release "
Round Two Interrogatory statement 8 "In response to the method outlined in 49 CFR 173.443(a)(1)
Denison Mines states "Using portable alpha detection eqiupment that measures the combined fixed
and removable contamination is therefore "another method" contemplated by paragraph 2. (49CFR
173.443(a)(2) "equal or greater efficiency"), because the Mill applies the removable contamination
standard to a combined reading of fixed and removable contamination." Provide efficiency
calculations to determine the efficiency of this method. Include the survey procedure used, the
efficiency ofthe meters and probes used in relation to U-238. Show that the meters and probes that
are/will be used has the appropriate sensitivity to provide a small enough reading to measure the
required release limits."
Based on manufacturer calibration sheets and information provided by the site RSO, Cs-137 is used
to calibrate the Ludlum Model-3 meters with the 44-9 GM pancake probes, thus they are not
calibrated for Alpha radiation. Also Sr-90 is used to perform a function check on the Model-3 meters
with 44-9 GM pancake probes. Both Cs-137 and Sr-90 are high energy Beta emitters and will
produce a higher efficiency than U-238, thus they are inappropriate to use for calibration or function
tests. Re-evaluate the efficiency for the Ludlum Model-3 survey meters with the 44-9 GM pancake
probe using U-238 or equivalent alpha source.
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BASIS FOR INTERROGATORY:
During the review of the calculations provided by Denison Mines, the reviewer requested
additional information from the Site RSO. The reviewer requested copies of the calibration
information and what sources were used when performing function checks on survey
instruments. In addition the reviewer contacted Ludlum to find out what the typical efficiency for
U-238 for Ludlum Model-3 survey meters with the 44-9 GM pancake probe. Ludlums response
was 15%. Using 15% in the same calculations that Denison Mines used in their response, the
Ludlum Model-3 survey meters with the 44-9 GM pancake probe is not sensitive enough to detect
U-238 at the applicable regulatory levels. A different meter and/or probe may need to be used to
do release surveys for ore trucks. (See attached emails)
Example: Using 15% efficiency and background used in Denison example.
MDC= 3 -\-4.65 X <IJ8b = 2906 dpm/lOOcm^ Alpha \
(1)(0.15)(0.15)
Denison Response:
Denison agrees that the alpha MDC for the Ludlum Model-3 survey meter with a 44-9 GM
pancake probe is 2,906 dpm/lOOcm^. However, when that meter and probe are used to measure
contamination on an ore tmck or other equipment, it is reading both alpha and beta. A combined
alpha and beta reading of less than 2,906 would be indicated as a non-detect. In the 14
radionuclides in the U-238 decay series in uranium ores, there are eight alpha particle and six
beta particle emitters. Considering that the 44-9-GM probe is more sensitive to beta radiation,
the total count rate could be considered roughly equally divided between alpha and beta counts.
Therefore, a total count reading of non-detect (<2,200 dpm/lOOcm^) would mean that, for ore
tmcks, the total alpha contamination would be less than about 1,500 dpm/lOOcm^. This is less
than the DOE standard for restricted release of 2,200 dpm/lOOcm" alpha. The Mill's practice
with these detectors is to send equipment back for re-decontamination if the meter shows any
reading higher than non-detect. For these reasons, Denison is comfortable that the release
criteria for ore tmcks and intermodal containers etc. have been applied conservatively at the site.
However, Denison realizes that the use of a combined alpha/beta meter such as the Ludlum
Model-3 survey meter with a 44-9 GM pancake probe has raised some concems. As a result,
commencing on or before April 30, 2010, Denison will use alpha detectors (as opposed to
alpha/beta detectors) with the same or equal efficiency as the alpha detectors currently being
used at the Mill for surveying equipment for unrestricted release at the site, such as the Ludlum
Model 177 counter and 43-5 alpha detector, for measuring potential alpha contamination on
tmcks and other vehicles and equipment.
Methods to estimate the MDA (minimum detectable activity) for survey instmments and
counters are discussed in NRC'S NUREG-1507 (Minimum Detectable Concentrations with
Typical Radiation Survey Instruments for Various Contaminants and Field Conditions, 1998).
DENISON Jl MINES
From NUREG-1507 (Equation 3-10), the following is given for the MDA when measuring
surface contamination:
^P^^3 + 4.65VCB
Kt
Where:
MDA = minimum detectable activity in disintegrations/min/100 cm^;
CB = background count rate (cpm);
t = counting time (min); and
K = proportionality constant which includes adjustments for detector efficiency and geometry
(e.g. coverage relative to 100 cm^).
Typical Denison data for the Model 177 counter with 43-5 alpha detector are:
Background count rate (CB) = 20 cpm \
Background counting time (t) = 1 min |
Detector alpha efficiency = 11 % (0.11) \
Probe active area = 50 cm^ (or 0.50 of 100 cm^ area under consideration)
Using these values in Equation (1), the MDA is estimated as:
x/fT^A 3-F4.65V20
MDA = -7 r
(0.11x0.50x1)
= 430 dpm/100 cm (rounded to two significant figures).
This MDA is well below both the 49 CFR173.443 standard of 22 dpm/cm^ (2200 dpm/100 cm^)
for non-fixed alpha contamination for restricted release of ore tmcks and other equipment, and
NRC's 1000 dpm/100 cm^ standard for non-fixed alpha contamination for unrestricted release of
tmcks and all other equipment from the Mill's restricted area (see NRC Regulatory Guide 8.30,
Health Physics Surveys in Uranium Recovery Facilities at Table 2 and Section 2.7).
2. SECTION 2, ENGINEERING COMMENT INTERROGATORIES - ROUND 1
2.1 INTERROGATORY STATEMENT - The Reclamation Plan:
I-B DRC Round 1 dated Juh 2. 2009:
Please update and complete the Section 8 of the License Renewal Application, regarding the
Reclamation Plan. Please include the current approved version of the Reclamation Plan as an
Appendix to the License Renewal Application.
DUSA Responded by Submitting a Letter dated Ausust 14, 2009, stating Revision 4.0 of the
Reclamation Plan would be forthcoming. Revision 4.0 of the plan was sent bv DUSA by letter
dated November 24, 2009:
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The DUSA letter of November 24, 2009 supplied a revised Section 8 to the License Renewal
Application as replacement pages. This letter states the Reclamation Plan is submitted as a new
Appendix P to the original License Renewal Application.
DRC Response:
The replacement pages to Section 8 ofthe License Renewal Application are acceptable, and have
been incorporated into the License Renewal Application.
The DUSA letter of November 24, 2009 states, "Denison is hereby submitting the enclosed
Revision 4.0 as a new Appendix P to the February 28, 2007 renewal application... "
However, the Index to Appendices in the February 28, 2007 License Renewal Application (i.e.
page vi) needs to be revised to add Appendix P. Also, a tab sheet and a place holder sheet,
stating the location of the new Appendix P, should be submitted to place in the License Renewal
Application appendices volume.
Denison Response:
Included as Attachment A to this letter are copies of:
• The Index to Appendices in the 2007 License Renewal Application revised to add
Revision 4.0 of the Reclamation Plan as Appendix P and the Cell 4A BAT Monitoring,
Operations and Maintenance Plan as Appendix Q;
• Tab Sheets; and
• Place Holder Sheets, stating the location of the new Appendices P and Q.
The two accompanying copies of the Index, Tab Sheets and Place Holder Sheets should be
inserted into the two copies of the 2007 License Renewal Application that were previously
provided to the Executive Secretary. In the case of the revised Index to Appendices, it should
replace the existing Index to Appendices in each of those copies of the Application.
2.2 INTERROGATORY STATEMENT - The Reclamation Plan:
I-C DRC Round 1 dated July 2, 2009:
Reeardins the Cell 1 Discharge Channel, on Figure A-2.2.4-1 Sedimentation Basin Detail:
1. The potential need for or absence of rip-rap protection for the Cell 1 discharge channel,
entry and exit platform aprons must be explained and justified. An adequate
demonstration will include, but is not limited to analysis according to NUREG-1623.
2. The need to join or not join (the existing configuration) the discharge channel to the toe
ofthe new south dike of Cell 1 must be explained and justified.
3. Drawing details are needed to show the outcome of the above analyses to describe the
sections of the discharge channel, its lining, appurtenant entry, exit apron zones, dike
alignment and lining.
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Basis for the Interrogatory:
1. The need for using rip-rap protection for the Cell 1 discharge channel, entry and exit
aprons need to be analyzed under Potential Maximum Precipitation and Flood.
2. It appears advantageous to connect the discharge channel to the toe of the new south
dike of Cell 1 to ensure entry flow path longevity, and to possibly eliminate need for rip-
rap armor south ofthe discharge channel on the west dike of Cell 1.
3. The construction requirements for the discharge channel, its lining, appurtenant entry,
exit apron zones, dike alignment and lining need to be specified....
References:
Reclamation Plan, Revision 3.0, Figure A-2.2.4-1 Sedimentation Basin Detail
NUREG-1623, Design of Erosion Protection for Long-Term Stabilization \
Chow, V.T. 1959, Design of Channels for Uniform Flow, Open Channel Hydraulics, McGraw-
Hill Book Company, p. 164-179.
DUSA Response dated August 14. 2009:
"The Cell Discharge Channel is intended to divert the water accumulated from the PMP storm ;
event from a 143 acre area, which includes the sedimentation basin created from the Cell area,
the reclaimed Mill area, and the area to the north ofthe Cell area but south ofthe existing
diversion ditches. The channel is created by excavation ofthe undisturbed ground to the west of
Cell 1 to maximum depth of approximately 17 feet. The lower 10 feet ofthe channel is
excavated in Dakota Sandstone to an elevation matching the lowest point on the west end ofthe
Cell 1 sedimentation basin. The channel will be excavated at slope of 1% and will daylight in
the Dakota Sandstone cliffs in Westwater Canyon. A cross section ofthe area to be excavated is
included in Appendix P to this letter."
"The maximum discharge volume through the channel will be 1344 cubic feet per second
resulting inflow velocity of 7.45 feet per second assuming bottom channel width of 120 feet
The channel design proposed in the reclamation plan is actually 150 feet wide at the bottom,
which will further reduce the flow velocity. The allowable flow velocity for bedrock channel
is 8-10 feet per second; therefore no riprap is required in the channel bottom. The entrance to
the channel will match the bottom elevation ofthe sedimentation basin; so no riprap will be
necessary at that point. The channel discharge will be on to the cliffs of Westwater Canyon;
therefore no riprap will be necessary at that point. The discharge calculations are included in
Attachment G to the Reclamation Plan, and also included in Appendix P to this letter.
"We do not believe that the discharge channel should be joined with the toe ofthe new fill area
on the north slope ofthe Cell 1 dike. The flows offthe dike slope will be very small and the rip
rap toe will easily protect the slope and the reclamation cover. The flow velocities at the
entrance to the discharge channel could possibly impact the rip rap toe, or require additional rip
rap, and should therefore be avoided. Water potentially backing up from the entrance to the
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discharge channel would be very low velocity in the area near the toe of the Cell 1 north slope
and would not impact the stability ofthe slope. "
DRC Response:
Interrogatory IC Item 1:
It appears the approach velocity at entry to the channel may exceed the scouring resistance of
the existing Cell 1 soil upstream ofthe channel, creating erosion prior to flow on the in-situ rock
lined chcmnel bed.
To support your claim that this is not a problem for the Cell 1 floor:
please analyze the dimensions, area of extent, cmd anticipated channel entry scour velocities in
accordance with methods outlined in NUREG-1623, and submit quantitative calculations for
DRC review.
If said calculations indicate soil scour will occur, please submit design for an appropriate
channel entryway rip-rap apron, to accommodate the area of scouring velocities, for revision to
the current Reclamation Plan Version 4.0. This calculation and/or the design change, plans and
specifications will need to be included as part ofthis License Renewal Application.
Denison Response:
Section 3.2.2.2 of Revision 4.0 of the Reclamation Plan describes the removal of contaminated
soils and process material from the Cell 1 area. Cell 1 was constmcted by excavating soils and
rock to the design contours, which resulted in the bottom of Cell 1 being entirely in the Dakota
Sandstone formation. The discharge channel is created by excavation of the undisturbed ground
to the west of Cell 1 to maximum depth of approximately 17 feet. The lower 10 feet of the
channel is excavated in Dakota Sandstone to an elevation matching the lowest point on the west
end of the Cell 1 sedimentation basin. The channel will be excavated at a slope of 1 % and will
daylight in the Dakota Sandstone cliffs in Westwater Canyon. The only soil present at the inlet
to the discharge channel is the topsoil placed on the bottom of Cell 1 as a part of the final
reclamation. In order to reduce the potential for erosion of the topsoil at the inlet to the
discharge channel, the plan has been modified to eliminate the topsoil within 100 to 150 feet of
the inlet and provide a band of rip rap, similar to the rock apron illustrated on Figure A-5.1-4, at
the transition from the topsoil to the Dakota sandstone. The flow velocities at this point will be
significantly lower than at the entrance to the discharge channel. Figure No. A-2.2.4-1 of
Revision 4.0 of the Reclamation Plan has been revised to show the revised area of topsoil and the
band of rip rap at the topsoil transition to the Dakota Sandstone. A copy of the revised Figure
No. A-2.2.4-1 is included as Attachment B to this letter. The two accompanying copies of this
revised Figure should be inserted as replacement Figures into the two copies of Revision 4.0 of
the Reclamation Plan that were previously provided to the Executive Secretary.
DENISON/I
MINES
Interrogatory IC Item 3:
The dimensions shown on the Reclamation Plan drawings for the Cell 1 outlet channel need to
be corrected to indicate the dimensions discussed by DUSA above. The Reclamation Plan
drawings currently show a 200-foot wide channel bottom. In contrast, your August 14, 2009
response said it would be 150-feet wide.
Please submit revised calculations (above) and corrected drawings of the channel dimensions
with plans and specifications for the rip-rap entry apron provision mentioned above for revision
to the current Reclamation Plan Version 4.0. This change will need to be included as part of
this License Renewal Application.
Denison Response:
The dimensions of the discharge channel have been revised on Figure No. A-2.2.4-1 of Revision
4.0 of the Reclamation Plan, to show the discharge channel as 150 feet wide. The revised Figure
is included as Attachment B to this letter. The two accompanying copies of the revised Figure
are to be inserted as replacement Figures into the two copies of Revision 4.0 of the Reclamation
Plan that were previously provided to the Executive Secretary. The calculations for the
discharge channel flow are in the existing Attachment G of Revision 4.0 of the Reclamation
Plan.
2.3 INTERROGATORY STATEMENT - The Reclamation Plan:
I-D DRC Round 1 dated July 2, 2009:
This interrogatory is being provided for DUSA's information only. This item will be pursued
concurrent with DRC review of the Infiltration and Contaminant Transport Modeling Report,
White Mesa Mill Site, Blanding Utah (ICTM) prepared by DUSA. Last correspondence on the
report was furnished by DUSA on April 30, 2009.
Is installation ofa rock apron at the base of all the final covered tailings cell outslope intended
for the entire perimeter of the final covered tailings cell system? If so, please clarify by
specifying on the drawings that such is required. If not, please demonstrate that the absence of
such will be adequate for the 1,000-year design period or at minimum a 200-year period.
Basis for the Interrogatory:
The reclamation plan drawings only distinctly specify rock aprons on the south outslope of Cell
4A. It is unclear if installation ofa rock apron at the base or toe of all dike outside side slopes is
intended. That is, are rock aprons to be installed for the entire perimeter of the tailings cell
system? Reclamation Plan figures A-5.1-1, -2, -3 and -4 show a plan view and cross-sections of
the tailings cells. The section A-A' on Figure A-5.1-2 on the left side refers to Fig. A-5.1-4,
which is a drawing of the "Rock Apron at Base of the Toe of the Cell Outslope. " None of these
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plan views or cross-sections specifically shows rock aprons, other than the south side of Cells
4A...
References:
Reclamation Plan, Revision 3.0, Figures A-5.1-1, -2, -3 and -4.
Reclamation Plan, Revision 3.0, Figure A-2.2.4-1 Sedimentation Basin Detail
NUREG-1623, Design of Erosion Protection for Long-Term Stabilization
Chow, V.T. 1959, Design of Channels for Uniform Flow, Open Channel Hydraulics, McGraw-
Hill Book Company, p. 164-179.
DUSA Response dated August 14, 2009:
"The questions raised in Interrogatory Statement I-D will be addressed in the re-design ofthe
tailings cover system in accordance with the approved ICTM."
DRC Response:
We agree that the need for rock aprons discussed above will be addressed by DUSA in the ICTM
study. However, we have determined that this issue must be addressed and resolved now as a
part of the License Renewal Application.
Due to the uncertain timeline for the ICTM study completion on this item, DUSA must submit
design analysis, plans and specifications for rock aprons for the tailings cells perimeter outslope
as discussed above.
The design for the rock aprons, as appropriate, will need to be included as part of this License
Renewal Application, and must comply with the engineering guidelines found in NRC NUREG
1623.
However, we realize the final design of appurtenant rock aprons for the outslope of the tailings
cells may be in accordance with an approved ICTM design, and will need to be included in the
future revision to the White Mesa Mill Reclamation Plan to be submitted for approval after
completion and approval ofthe ICTM study.
Denison Response:
Figures A-5.1-1, -2, and -3 of Revision 4.0 of the Reclamation Plan have been revised to clarify
the requirement for rock aprons to be placed on the 5h:lv outslopes of the reclaimed tailings
area. This was the original intent of the reclamation design, and had been included in the
estimated costs in Attachment C to revision 4.0 of the Reclamation Plan. These revised Figures
are included as Attachment C to this letter. The two accompanying copies of these revised
Figures are to be inserted as replacement Figures into the two copies of Revision 4.0 of the
Reclamation Plan that were previously provided to the Executive Secretary. The design for the
rock apron outslope protection is contained in Attachment G to Revision 4.0 of the Reclamation
Plan.
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2.4 INTERROGA TORY STA TEMENT - The Reclamation Plan:
I-E DRC Round 1 dated July 2, 2009:
Please demonstrate that for final reclamation ofthe tailings cells a filter blanket is necessary or
unnecessary to be installed below the riprap cover, for the top, side slopes, and rock aprons of
the tailings cells.
Basis for the Interrogatory:
There is no filter blanket shown or specified in the Reclamation Plan. A demonstration of layer
stability is needed to justify the omission of a filter blanket in the cover design.
Also, we recognize that different engineering design has been proposed by DUSA in the
November 21, 2007 Infiltration and Contaminant Transport Modeling Report, White Mesa Site,
Blanding, Utah, prepared by MWH Americas Inc. Erosion stability issues and radon controls
must be considered in the final reclamation plan and must be closely coordinated with ICTM
report that may be approved later.
Regulatory Basis:
1. R313-24-4. Uranium Mills and Source Material Mill Tailings Disposal Facility
Requirements -Clarifications or Exceptions incorporate 10CFR40 Appendix A with some
exceptions and substitutions.
2. 10CFR40, Appendix A, Criterion 9 requires an Executive Secretary approved
reclamation planfor the White Mesa Mill.
References:
1. 2002, T.L. Johnson, NUREG-1623, Design of Erosion Protection for Long-Term
Stabilization, Appendix D, Designing Riprap Erosion Protection, Paragraph 2.1.1, Filter
Requirements: "It is generally recommended that a filter or bedding layer comprised of
well-graded rock material be placed on the cover or in locations where rock riprap is to
be placed for erosion protection. Locations recommended for filter placement include
impoundment side slopes, toes of slopes, transition areas, diversion ditches and channels,
stilling areas, and fiow impact areas. The purpose of the filter is to bed the riprap and
prevent stone penetration into the cover and/or radon barrier, prevent soil erosion from
flow at the stone/soil interface, and to prevent the pooling of precipitation and/or
tributary runoff from infiltrating into the cover and waste materials. Filter sizing criteria
are presented in NUREG/CR-4620 (Nelson, 1986). "
2. Same Drawing References, per the interrogatory immediately above this one.
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DUSA Response dated August 14. 2009:
"It is not clear why filter blanket was not included in the original cover design. As noted by
DRC, Denison is proposing revised cover design as part of the Infiltration Analysis [ICTM]
which will eliminate the rip rap on the top surface ofthe reclaimed tailings. The need for a filter
blanket on the embankment side slopes and toe areas will be evaluated at that time. "
DRC Response:
We agree that the need for the filter blanket discussed above will be addressed by DUSA in the
ICTM study. However, we have determined that this issued must be addressed and resolved now
as a part ofthe License Renewal Application.
Due to the uncertain timeline for the ICTM study completion on this item, DUSA must submit
design analysis, and plans and specifications for a filter blanket to be installed below all riprap
cover, including but not limited to the top, side slopes, channel lining aprons and dike outslope
rock aprons ofthe tailings cells.
The design for the filter blankets will need to be included as part of this License Renewal
Application, and must comply with the engineering guidelines found in NRC NUREG 1623.
However, we realize the final design of the filter blanket for the rip/rap system may be in
accordance with an approved ICTM design, and will need to be included in thefuture revision to
the White Mesa Mill Reclamation Plan to be submitted for approval afier completion and
approval ofthe ICTM study.
Denison Response:
Included as Attachment D to this letter a January 29, 2010, Technical Memorandum from MWH
Americas, Inc. that evaluates the need for a filter layer below the side slope riprap cover included
in the existing design. MWH's conclusion is that the filter layer is needed on the side slopes, but
not on the toe slope or toe apron areas. The details of the analysis and a recommendation for
fiUer sizing are included in the MWH Technical Memorandum. Figure A-5.1-3, Detail 2 of
Revision 4.0 of the Reclamation Plan, has been revised to indicate the requirement for the filter
layer in the reclaimed side slopes. The revised Figure is included as Attachment C to this letter.
The two accompanying copies of the revised Figure are to be inserted as replacement Figures
into the two copies of Revision 4.0 of the Reclamation Plan that were previously provided to the
Executive Secretary. The two accompanying copies of the January 29, 2010, Technical
Memorandum from MWH Americas, Inc. should be inserted as an addition to Attachment G into
the two copies of Revision 4.0 of the Reclamation Plan that were previously provided to the
Executive Secretary. The additional cost for production and placement of the filter layer will be
included in the next revision to the Reclamation Plan Cost Estimate, due March 4, 2010.
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2.5 INTERROGATORY STATEMENT - The Reclamation Plan:
I-F DRC Round 1 dated July 2, 2009:
Reclamation Plan Fig. 3.2.3-1, Site Map Showing Locations of Buildings and Tankage needs to
be updated to current conditions....
DUSA Responded by Submitting a Revision 4.0 ofthe Reclamation Plan on November 24, 2009:
The DUSA letter of November 24, 2009 conveyed a revised Figure 3.2.3-1 in Reclamation Plan
Version 4.0.
DRC Response:
The revised Figure 3.2.3-1 provided has been reviewed. This figure does not provide a current
map ofthe tanks and the tank solutions that are depicted by the DUSA letter dated July 15, 2009,
subject: Tank Layout and Update. Please revise and update Figure 3.2.3-1 in accordance with
this latest information, to ensure that it is complete and representative of current site conditions.
Denison Response:
The revised Figure 3.2.3-1 of Revision 4.0 of the Reclamation Plan is included as attachment E
to this letter. The two accompanying copies of the revised Figure are to be inserted as
replacement Figures into the two copies of Revision 4.0 of the Reclamation Plan that were
previously provided to the Executive Secretary.
2.6 INTERROGATORY STATEMENT - The Reclamation Plan:
I-G DRC Round 1 dated July 2. 2009;
In the DRC copy of the Reclamation Plan, Appendix [Attachment] G, Attachment 9, Rainfall-
Duration Curve for One-Hour PMP at White Mesa Mill is illegible. Please provide a readable
copy of the graph....
DUSA Response dated August 14, 2009:
"A readable copy of Reclamation Plan, Appendix [Attachment] G, Attachment 9, Rainfall-
Duration Curve for One-hour PMP at White Mesa Mill is attached as Appendix Q to this letter. "
DRC Response:
We note this submittal. The response is acceptable. The subject rainfall duration curve has been
integrated into the submitted Reclamation Plan Version 4.0 as well as the current Reclamation
Plan.
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Per Appendix F, Table IC of the Tailings Cover Design White Mesa Mill 1996, by Titan
Environmental Corporation, the minimum D50 for the rip-rap diameter for top portion of the
cover is to be 3.4 inches.
Drawing A-5.1-3 in the Reclamation Plan Rev 4.0 lists the D50 as 0.3 inches. Please correct this
error on the drawing.
Denison Response:
Figure A-5.1.3 of Revision 4.0 of the Reclamation Plan has been revised to specify a D50 of 0.34
inches for the rip-rap diameter for top portion of the cover. This is consistent with Appendix F,
Table IC of the Tailings Cover Design White Mesa Mill 1996, by TUan Environmental
Corporation. Revised Figure A-5.1.3 of Revision 4.0 of the Reclamation Plan is included in
Attachment C to this letter. The two accompanying copies of the revised Figure are to be
inserted as revised Figures into the two copies of Revision 4.0 of the Reclamation Plari
previously provided to the Executive Secretary.
2.7 INTERROGATORY STATEMENT - The Reclamation Plan:
/-/ DRC Round 1 dated July 2, 2009: \
In the Reclamation Plan on pp. B-2 and B-16, the Final Construction Report is referred to. This
report is important to independently document the completion of the reclamation and
decommissioning work. In that regard, please revise the Reclamation Plan to include the
following:
1. Please remove any reference to NRC/DRC field presence in the Reclamation Plan.
2. The report must be submitted to the DRC within 180 calendar days after the apparent
completion of Construction, for Executive Secretary review and approval.
Basis for the Interrogatory:
There is no current distinct requirement in the license for a Final Closure Report. There are
many regulatory and administrative needs for such a report
Regulatory Basis:
1. R313-24-4. Uranium Mills and Source Material Mill Tailings Disposal Facility
Requirements -Clarifications or Exceptions incorporate 10CFR40 Appendix A with some
exceptions and substitutions.
2. 10CFR40, Appendix A, Criterion 9 requires an Executive Secretary approved
reclamation planfor the White Mesa Mill.
3. R313-24-l(3)
4. R313-22-36(10)
5. R313-22-34(7)
6. R313-22-34(l)
DENISO
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References:
Reclamation Plan, Attachment B, Quality Plan for Construction Activities White Mesa Project
Blanding, Utah.
DUSA Responded by Submitting a Revision 4.0 ofthe Reclamation Plan on November 24, 2009:
The Reclamation Plan, Revision 4.0 made most of the appropriate changes to the specified
verbiage.
DRC Response:
References to the NRC appear to be removed from the Reclamation Plan, Revision 4.0.
However, the verbiage on the last sentence on page B-2 needs correction. Please correct this
sentence and resubmit this page as a revision to the current Reclamation Plan Version 4.0. This
change will need to be included as part ofthis License Renewal Application.
Denison Response:
No revision is needed to page B-2 of Revision 4.0 of the Reclamation Plan. Included in
Attachment F to this letter are each ofthe revised Forms Nos. F-23, -25, and -26 of Revision 4.0
of the Reclamation Plan. These revised forms reflect the requested updating edits. The two
accompanying copies of these revised forms are to be inserted as replacement pages 20, 21 and
22, Attachment B, into the two copies of Revision 4.0 of the Reclamation Plan that were
previously provided to the Executive Secretary.
2.8 INTERROGATORY STATEMENT - The Reclamation Plan:
I-L DRC Round 1 dated July 2. 2009:
"The tailings cell cover design found in the Reclamation Plan provided with the February 28,
2007 License Renewal Application is not the same as that provided in the November 21, 2007
Infiltration and Contaminant Transport Modeling (ICTM) Report, White Mesa Site, Blanding,
Utah, prepared by MWH Americas Inc. It will be DUSA's responsibility to amend the License
Renewal Application and the Reclamation Plan to ensure that the tailings cells cover design,
plans, specifications and construction ultimately authorized conforms to the approved ICTM
Report."
Basis for the Interrogatory:
Provisions in the existing License Renewal Application and Reclamation Plan will need to be
adjusted to ensure that the tailings cells cover design, plans, specifications and construction
conforms to the approved ICTM...
DENISON Ji MINES
14
DUSA Response:
The Reclamation Plan, and to the extent applicable the 2007 License Renewal Application, will
be amended to ensure that the tailings cell cover design, plans, specifications and construction
ultimately authorized conform to the approved ICTM. Denison expects that the resulting
changes to the Reclamation Plan may be significant, and may justify the creation of Revision
5.0 ofthe Reclamation Plan in order to properly incorporate the changes into the Plan.
DRC Response:
We agree that depending on the approval date for the ICTM Report, DUSA will probably need to
issue a future revision to the Reclamation Planfor approval, incorporating the approved ICTM
plan provisions, rather than incorporate such provisions in the submitted Reclamation Plan
Revision 4.0. So, at a future date, an approved Reclamation Plan incorporating the approved^
ICTM study would then need to be included as part of next license amendment after approval of
the current License Renewal Application. I
However, it is imperative that Revision 4.0 of the Reclamation Plan be reviewed and approved
by DRC to reflect the most currently available design for closure conditions. To this end, it is
important DUSA complete all present issues in this Interrogatory, so that DRC review of the
License Renewal Application can move forward.
Denison Response:
No response is required.
2.9 INTERROGATORY STATEMENT- Correct Version of Documents
II-D DRC Round 1 dated July 2, 2009:
The edition of the White Mesa Mill Tailings Management System and Discharge Minimization
Technology (DMT) Monitoring Plan (DMT Plan) provided as tab 3.1 of Appendix A of the
License Renewal Application, is not the approved version. Please replace it with the approved
"09/08 Revision: Denison-6" version of the plan and attachments...
DUSA Response dated August 14, 2009:
"Attached as Appendix E is the approved 09/08 Revision Denison-6 version ofthe White
Mesa Mill Tailings Management System and Discharge Minimization Technology (DMT)
Monitoring Plan."
DENISO
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J>ii
DRC Response:
We have reviewed this response, and find the correct document was submitted, and is
acceptable. The currently approved DMT Plan, approved by the DRC on September 17, 2008
has been incorporated into the License Renewal Application.
Denison Response:
No response is required.
2.10 INTERROGATORY STATEMENT- Omission of Document
II-E DRC Round 1 dated July 2. 2009:
The License Renewal Application appears to not contain the Cell 4A BAT Monitoring,]^
Operations and Maintenance Plan (O&M Plan). Please include the latest approved edition in\
the application...
DUSA Response dated August 14, 2009:
"Attached as Appendix L is version 09/08 Revision Denison 1.3 ofthe Cell 4A BAT Monitoring
Operations and Maintenance Plan which is the latest approved edition of that plan. "
DRC Response:
We have reviewed this response and find the document submitted acceptable.
However, the Index to Appendices in the February 28, 2007 License Renewal Application need
to be added for the O&M Plan. A tab sheet should be submitted to place the O&M Plan into the
appropriate License Renewal Application appendix volume.
Denison Response:
Included as Attachment A to this letter are copies of:
• The Index to Appendices in the 2007 License Renewal Application revised to add
Revision 4.0 of the Reclamation Plan as Appendix P and the Cell 4A BAT Monitoring,
Operations and Maintenance Plan as Appendix Q;
• Tab Sheets; and
• Place Holder Sheets, stating the location of the new Appendices P and Q.
The two accompanying copies of the Index, Tab Sheets and Place Holder Sheets should be
inserted into the two copies of the 2007 License Renewal Application that were previously
provided to the Executive Secretary. In the case of the revised Index to Appendices, it should
replace the existing Index to Appendices in each of those copies of the Application.
DENISO
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^ii
An electronic version of this letter and Attachments is included on the accompanying disk.
If you should have any questions or require additional infonnation, please contact the
undersigned.
Yours very tmly,
DENISON MINES (US.^) CORP.
By:
David C. Frydenlund
Vice President, Regulatory Affairs and Counsel
cc: Ron F. Hochstein
Harold R. Roberts
Jo Ann Tischler
David E. Turk
DENISO
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17
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Attachment A
Appendix
A
B
C
D
E
F
G
H
I
J
K
L
M
N
o
P
Q
This page was revised on March 3, 20 I 0
INDEX TO APPENDICES
Description
Environmental Protection Manual
Release and Shipping of Vanadium B lackflake,
Standard Operating Procedure
Stormwater Best Management Practices Plan
Emergency Response Plan
Radiation Protection Manual
Ore Receiving, Feed and Grind Standard
Operating Procedure
Uranium Precipitation, Drying and Packaging
Standard Operating Procedure
SERP Standard Operating Procedure
ALARA Program
Training Program
Security Program
Respiratory Protection Program
GWDP Quality Assurance Plan
Transportation Accidents Plan
Inspection Reports and Notices of Violation
Reclamation Plan, Revision 4.0
Cell 4A BAT Monitoring Operations and
Maintenance Plan
VI
Appendix P
Reclamation Plan, Revision 4.0
Appendix Q
Cell 4A BAT Monitoring Operations and Maintenance Plan
Attachment B
Attachment C
Attachment D
(®MWH TECHNICAL MEMORANDUM
BUILDING A BE'ITIIR WORLD
TO: Doug Oliver
DATE: January 29,2010
FROM: Roslyn Stern
SUBJECT: Evaluation of need for filter layer on side slopes of Denison's White
Mesa Mill Tailings Cell Cover
The following evaluation was perfonned to evaluate the need for a filter layer under the
rock layer on the side slopes of the tailings cells cover for the White Mesa Mill.
Supporting assumptions, calculations, and discussion are provided following the
conclusions and recommendations.
Conclusions and Recommendations
The calculated interstitial velocities on the top slope and the toe apron are sufficiently
low that a bedding layer is not necessary. However, the interstitial velocity within the
erosion protection on the side slopes is within the range of values where bedding is
conditionally recommended. Because of the wide difference in grain size distribution
between the erosion protection and the random fill, it is recommended that a 6-inch layer
(for constructability) of bedding material be placed between these two materials. The
bedding material should be medium sand with the following specifications:
Sieve Size
3 inches
No.4
No. 20
No. 200
Percent Passing
100
65-100
20-70
0-5
The need for a rock layer on the sideslopes and underlying filter zone can be evaluated as
part of the detailed cover design. The rock layer on the sideslopes could be replaced with
a rock mulch (gravel-amended topsoil) that has the appropriate median size for erosion
protection. A rock mulch (gravel-amended topsoil) is being proposed for the cover
surface.
3665 ,WI< Parkway TEL [phone]
Suile 206 FAX [phone]
Fort Collins, Colorado 80525 www.mwhglobal.com
®MWH TECHNICAL MEMORANDUM
BUILDING A BBTTBR WORLD
Supporting Documentation and Discussion
Problem Statement
Evaluate the need for bedding layer between cover soils and erosion protection material
(rock) by estimating interstitial pore velocities using method proposed by Abt et al.
(1991). This evaluation is being completed for the currently pelmitted rock cover design.
Assumptions
• Reclamation cover, as described in Section 3.2.2 of the 2000 Reclamation Plan
(International Uranium Corp, 2000) consists of six-foot soil cover. The cover
consists, from bottom to top, of a minimum of three feet of random fill (platform
fill), one foot of clay, and two feet of random fill (frost batTier).
• Cells 2 and 3 will have final cover placed at a 0.2 percent grade, with 5H: I V side
slopes (Section 3.2.2.3).
• Erosion protection on the top surface of the cover will be provided by placing a
minimum of 3 inches of riprap with a median diameter (050) of 0.3 inches
(Section 3.3.5) and a OJOo of 0.6 inches (Section 6.2 of Attachment A -Plans and
Specifications). The overland flow velocity calculated for the top of the cover is
less than 2.0 ft/sec (Section 3.3.5).
• Erosion protection of the side slopes of the cover will be provided by placing a
minimum of8 inches of rip rap with a 0 50 of3.5 inches (Section 3.3.5) and a OJOo
of7 inches (Section 6.2 of Attachment A -Plans and Specifications). The
calculated flow velocity on the side slopes is 4.9 ft/sec (Section 3.3.5).
• Erosion protection of the toe apron will be provided by placing riprap with a 0 50
of6.4 inches (Section 3.3.5) and a OJOo of 12 inches (Section 6.2 of Attachment
A -Plans and Specifications).
• As described in Section 5.2 of Attachment A (Plans and Specifications), the
random fill used as platform fill and frost batTier protection is specified to have at
least 30 percent of the material finer than the number 40 sieve, with a 0 100 less
than 8 inches.
• The peak unit discharge from the tailings cells is 1.8 cfs/ft (Attachment 12 to
Attachment G -Channel and Toe Apron Design Calculations)
3665 JFK PmkWDY TEL [phone]
Suite 206 FAX [phone]
r-ort Collins, Colorado 80525 vNNI.mwhglobal.com
({ID MWH TECHNICAL MEMORANDUM
BUILDING A BETTER WORLD
Discussion
NUREG-1623, Appendix D, recommends a filter or bedding layer be placed under
erosion protection if interstitial velocities are greater than I ft/sec, in order to prevent
erosion of the underlying soils. Bedding is not required if interstitial velocities are less
than 0.5 ft/sec, and recommended depending on the characteristics of the underlying soil
if velocities are between 0.5 and I ft/sec.
Interstitial velocities are calculated by procedures presented by Abt et al. (1991) as given
in the following equation. This method updates the Leps (1973) relationship that is
presented in NUREG/CR-4620 (Nelson et al. 1986):
Where:
~ = O.23(g X DIO x sf'
Vi = interstitial velocities (ft/s),
G = acceleration of gravity (ft/s2),
DIO = rock diameter at which 10 percent is finer (inches), and
S = gradient in decimal fOlm.
The maximum DIO of the erosion protection is estimated based on Dso required for
erosion protection, assuming the erosion protection will have a coefficient of unifOlmity
(CU) of 6 and a band width of 5. Band width refers to the ratio of the minimum and
maximum allowed paliicle sizes acceptable for any given percent finer designation.
USDA (1994) recommends CU to be a maximum of 6 in order to prevent gap-grading of
filters. Table I summarizes the results.
Table I Results of Bedding Requirements
Location Top Cover Cover Side Slopes Toe Apron
Minimum Dso 0.3 3.5 6.4
(inches)
Maximum Dlo 0.35 1.24 3.73
(inches)
Slope (%) 0.2 20 I
Interstitial Velocity 0.03 0.65 0.25
(ft/s)
3665 JFK Parkway TEL [phone] 'lO Suilo 206 FAX [phone]
Fort Collins, Colorado 80525 \wNI,mwhglobal.com
«J) MWH TECHNICAL MEMORANDUM
BUILDING A BBTTER WORLD
References
Abt, S.R., J.F. Ruff, and RJ. Wilter (1991). Estimating Flow Through Riprap, Joumal of
Hydraulic Engineering, v. 117, No.5, May.
International Uranium (USA) Corp (2000). Reclamation Plan, White Mesa Mill,
Blanding, Utah, Revision 3.0, July.
Johnson, T.L. (2002). Design of Erosion Protection for Long-Term Stabilization,
NUREG-1623, U.S. Nuclear Regulatory Commission (NRC), February.
Nelson, J.D., S.R. Abt, R.L. Volpe, D. van Zyl, N.E. Hinkle, W.P. Staub (1986)
Methodologies for Evaluating Long-Tenn Stabilization Designs of Uranium Mill tailings
Impoundments, NUREG/CR-4620, U.S. Nuclear Regulatory Commission (NRC), June.
U.S. Department of Agriculture (USDA) (1994). Gradation Design of Sand and Gravel
Filters, National Engineering Handbook, Part 633, Chapter 26, October.
3665 JFK Pclrkw<lY TEL [phone]'10
Suite 206 FAX [phone]
Fort Collins, Colorado 80525 Vlwvv.rnwhglobaLcom
Attachment E
Attachment F
Form No. 1'-23 Pilge B-20
COMPLIANCE REPORT
Project No. __ _
Construction Segment. _____ _
Drawing No. ________ _
Specification No. _________ _
Description of Completed Construction Segment
Revision 4.0
Denison Mines (USA) Corp.
White Mesa Mill Reclamation Plan
Dato ____ _
._--_ .. -._------------
By: QC Officer ________________ .. _______ .. __
Approvals
Site Manage' _________________________ _
Form No. F-25
Project No. _______ _
Drawing No. _______ _
FIELD CHANGE ORDER
Page B-21
Revision 4.0
Denison Mines (USA) Corp.
White Mesa Mill Reclamation Plan
Date ___________ _
Specification No., ________ _
Design Feature
Modifications
Reason
Initiated by: ________________________ _
Approved by: _______________________ _
Site Manager
Form No, 1'-26 Page 8-22
Revision 4,0
Denison Mines (USA) Corp,
White Mesa Mill Reclamation Plan
DESIGN CHANGE FORM
Project No, Date ____ .. ________ _
Drawing NO. __ ...... _____ _
Specification No, __ _
Design Feature
Change in Design
'---------_._--_ .... _ .. -
Reason
-----------
Initiated by: ______ . _________________ _
Approvals:
Site Manager ___ .. _. _____________ _
DRC Project Manager _____________________ _
Design Engineer ____ ,
Attachment G
Revision 4.0
Denison Mines (USA) Corp.
White Mesa Mill Reclamation Plan
SCHEDULE OF AMENDMENTS
The following is a schedule that identifies all amendments made to the Plan since its date of
issuance on November 24, 2009:
Date of Amendment Section, Page, Table, Figure, Attachment Revision Date or
or Appendix, and Nature of Amendment Revision No., if
Applicable
March 3, 2010 Replaced Figure A-2.2.4-1 with revised March 2010
version
March 3, 2010 Replaced Figures A-S.I-I, A-S.I-2 and A-March 2010
S.I-3, with revised versions
March 3, 2010 Added January 29, 2010 Technical March 2010
Memorandum from MWH Americas, Inc. to
the end of Attachment G to the Plan
March 3, 2010 Replaced Figure 3.2.3-1 with revised version March 2010
March 3, 2010 Replaced Forms Nos. F-23, F-2S and F-26 of NA
Attachment B, with revised versions
March 3, 2010 Replaced Attachment C in its entirety Revision 4.1
This Schedule was last revised on March 3, 2010