DRC-2010-005482 - 0901a068801cb8a0

State ofUtah
GARY R. HERBERT
Govemor
GREG BELL
Lieutenanl Governor
Department of
Environmental Quality
Amanda Sniith
Execulive Direcior
DIVISION OF RADIATION CONTROL
Rust Lundberg
Director
DRC-2010-005482
September 29, 2010
David Frydenlund, Vice President Regulatory Affairs and Counsel
' Denison Mines (USA) Corp.
1050 17'*'Street, Suite 950
Denver, Colorado 80265
RE: Radioactive Material License (RML) Number UTI 900479: Health Physics Inspection
RADMOD-RWP-02
Dear Mr. Frydenlund:
On September 21, 2010, an inspection was conducted at your facility by Ryan Johnson, a-
representative of the Division of Radiation Control of the Utah Department of Environmental
Quality. Observations from the inspection were discussed with Rich Bartlet and Ronnie Nieves at
the closeout meeting. The inspection was an examination of the activities conducted in your ,
facility as they relate to compliance with the Utah Radiation Control Rules, the conditions ofthe
Mills RML and Federal Regulations. The inspection consisted of an examination of
representative records, interviews of personnel, and observations by the inspector. During the
closeout meeting the DRC inspector made recommendations regarding items for improvement.
These recommendations can be found at the end of the inspection report under recommendations.
Enclosed is the inspection report regarding this inspection for your review. The DRC would like
to thank the Mill staff for their cooperation regarding this inspection. If you have any questions
conceming this letter contact Mr. Ryan Johnson [phone].
UTAH RADIATION CONTROL BOARD
Rusty Lundberg, Executive Secretary
RL/RJ:r)
Cc; David Turk, Site Radiation Officer
Enclosures
195 Nonh 1950 West • Salt Lake City, UT
Mailing Address: P.O. Box 144850 • Salt Uke City, UT 84114^850
Telephone [phone] • Fax [phone] • T.D.D. [phone]
www.deq.utah.gov
Printed on 100% recycled paper
INSPECTION REPORT
Inspection Module: RADMOD-RWP-02: Radiation Work Permits, Personal Protection
Equipment and Daily, Weekly and Monthly Inspections
Inspection Location: Denison Mines- White Mesa Uranium Mill, Blanding Utah.
Inspection Items: Radiation Work Permits, Personnel Protection Equipment and Daily,
Weekly and Monthly Inspections
Inspection Dates: September 21, 2010
Inspectors: Ryan Johnson, Utah Division of Radiation Control (DRC)
Personnel Contacted:
Dave Turk (Radiation Safety Officer (RSO)) Ronnie Nieves (Radiation Coordinator)
Ryan Palmer (Environmental Technician)
Goveming Documents:
• UACR313-15
• NRC Regulatory Guide 8.31
• Radioactive Materials License (RML) UTI900479
RML UTI 900479 License Renewal Application (2/28/07)
Opening Meetine
Denison Mines: Dave Turk (RSO)
Ronnie Nieves (Radiation Coordinator)
Ryan Palmer (Environmental Technician)
Utah DRC: Ryan Johnson (DRC Inspector)
During the opening meeting, the inspector discussed the items ofthe inspection. These items
included the documentation to be reviewed and the specific areas of the Mill that the inspector
wanted to see during the inspection.
Inspection Items:
• Radiation Work Permits (RWPs)
• Personal Protection Equipment (PPE)
• Daily Inspections
• Weekly Inspections
• Monthly Reports
• Follow-up Items
o 1 le(2) disposal
o Intermodal Release Surveys
o Personnel Exit Surveys ,
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Item 1. RWPs: The inspector reviewed RWPs from the last two years, specifically looking at the
information that is required by the Mills Radiation Protection Manual (Work to be done, Location
of the work, Duration of the work, Personnel doing the work, PPE requirements, Monitoring
requirements and the RSO signature). The inspector observed that the RWPs were filled out by
members of the Radiation Safety staff and the Occupational Safety staff. The inspector also
observed that most RWPs had supporting documentation attached to them (Safe Work Permits,
Confined Space Permits and Bioassay Results). Also in the Mills Radiation Protection Manual
RWPs are required for the receipt, handling and processing of any altemate feed material unless
there is a Standard Operating Procedure (SOP) for it. Currently the Mill is processing UF4
altemate feed material and it has its own SOP. The inspector reviewed the UF4 SOP to verify that
it covered the radiation safety concems for UF4 material.
The inspector discussed with the Radiation Coordinator whether the radiation safety staff has
sufficient time to prepare RWPs and how the radiation safety staff verifies that the RWPs are being
followed. During this discussion the Radiation Coordinator indicated that the staff has sufficient
time to prepare RWPs (approximately 20 minutes) and that the Radiation Safety staff verifies that
RWPs are being followed during their daily inspections.
There was one RWP currently approved and in progress during the inspection for removing super
sacks from the alternate feed "fan steel" material so it can be processed with convendonal ore. On
the day of the inspecdon no work was being done in association with that RWP and the inspector
was not able to observe work being done and verify that the RWP is being followed.
Deficiencies: TTie inspector observed that the estimated exposure line was not being properly filled
out. Mill staff members were inconsistent on how to document this information. Some staff
members were putting the calculated approximate dose, others were putting the different routes of
entry and some were leaving it blank. The inspector spoke with RSO about these observations and
the RSO said that a new Radiation Technician Training manual is waiting to be approved by the
corporate office and these inconsistencies are addressed in that.
Item 2. PPE: The inspector discussed with the RSO the PPE requirements for all of the different
departments within the Mill. During the Mill tour the inspector observed that Mill employees were
wearing the appropriate PPE for each department that they work in. The inspector discussed with
the Radiation Coordinator:
• How Mill employees receive information on what PPE they are required to use;
• How Mill employees replace worn-out PPE;
• How the Mill verifies employees are using the PPE that they are supposed to use; and
• Where PPE is stored at the Mill.
The inspector observed Decon personnel not wearing face shields while decontaminating an
intermodal container. When the inspector brought up this concem, the RSO said that face shields
are not required.
Deficiencies: The inspector verified that face shields are not listed as required PPE for washing
intermodals. However, the inspector deems the use of face shields is a practice that should be
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\
\ considered as part of the ALARA philosophy for personnel working at the Decon Pad.
Item 3. Daily Inspections: The inspector reviewed the Daily Inspection Reports for the past year.
The inspector observed that daily inspections were being done and that the Daily Inspection Sheet
was divided into different areas of the Mill for the Mill staff inspect.
Deficiencies: Based on the above paper review, the inspector could not determine if the radiation
safety staff was verifying that RWPs were being followed because the daily inspection report does
not document that Mill employees assigned to that work were following the RWP.
Item 4. Weekly Inspections: The inspector reviewed the Weekly Inspection Reports for the past
year. The inspector observed that safety and radiological safety concems (i.e. yellowcake spills)
were being identified and that different Mill department managers were being contacted to get
., them corrected.
Deficiencies: The inspector observed that things were being identified that needed to be taken care
of but there was no documentation if those identified items were being corrected.
Item 5. Monthly Reports: The inspector reviewed the monthly reports from the last year.
Specifically, the inspector looked for the information that is required by the Mills Radiation
Protection Manual;
• A summary of recent personnel exposure data, including bioassay and time -weighted
calculafions;
• A summary of all pertinent radiation survey records;
• A discussion of any trends or deviafions from the radiation protection and ALARA
programs, including and evaluafion of the adequacy of the implementafion of license
condifions regarding radiafion protection and ALARA; and
• A description of umesolved problems and the proposed corrective measures.
Deficiencies: None
Item 6. Follow-up Items: The following were items that the inspector was following-up on from
previous inspecfions:
• 11 e(2) disposal: The inspector observed 11 e(2) material being disposed of in Cell #3. This
material was not placed in a slit trench because it was a soil not debris.
• Intermodal Release Surveys: The inspector observed an unrestricted survey on an
intermodal container. The inspector performed a verification survey on the same intermodal
container. Both the Radiation Technician and inspector did not find any contaminafion
levels above Department of Transportation limits.
• Personnel Exit Surveys: The inspector observed Mill employees surveying themselves as
they exit the restricted area. The Mill employees that were observed were surveying
themselves appropriately.
Deficiencies: None
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ReportRADMOD-RWP-02 9-21-10RJl.doc
Closeout Meeting
Denison Mines:
Utah DRC:
Findings
None
Rich Bartlet (Mill Manager)
Ronnie Nieves (Radiafion Coordinator)
Ryan Johnson (Inspector)
Recommendations
During the close out meeting the DRC inspector made the following recommendations regarding
items for improvement:
1. Train the radiafion safety staff and the occupational safety staff on the appropriate way to
fill out the RWP form specifically the estimated exposure line.
2. Add face shields to the required PPE for personnel decontaminating tmcks, intermodals and
equipment.
3. Add a RWP section to the Daily Inspection Report to document that acfive RWPs are being
adhered to.
4. Document with the Weekly Inspecfion Report when non-compliance and safety items
identified during weekly inspections have been corrected.
Recommendation for Next Inspection
1. Observe ISL material being placed in slit trenches on Tailing Cell #3
2. Employee Exit Monitoring
3. Continue to do verification surveys on intermodals and ore tmcks
4. Spills (yellowcake and other materials) being cleaned up in the mill immediately
Prepared By: Ryan Johnson
(Print Name) x
9/29/10
(Date)
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I UTAMIVISION OF RADIATION COWROL
RADIATION PROTECTION INSPECTION MODULE RADMOD-RWP-02
RWPs/PPE
DENISON MINES - WHITE MESA URANIUM MILL
RADIOACTIVE MATERIAL LICENSE UTI900479
References: Radioacfive Material License UTI900479, License Renewal Applicafion dated Febmary 28, 2007,
Radiafion Protecfion Manual, Section 5, 10CFR20, NRC Regulatory Guide 8.30, NRC Regulatory Guide 8.31,
Utah Administrative Code R313-15.
RADIATION WORK PERMITS (Appendix E Section 5, 2007 License Renewal)
Radiafion Protection Manual Secfion 5 Radiation Work Permits (RWPs) (Appendix E license renewal)
1) According to the Radiafion Protection Manual RWPs are required to contain the following informafion and
copies ofthe RWPs are kept on file for five years. Review five (5) RWPs from the past 2 years (starting
from the present year). Verify (Yes or No) that the forms contain all of the informafion that is required.
Date RWP
Number
Work to
be Done
Location
of Work
Duration
of Work
Personnel
Woridng
PPE
Required
Monitoring
Required
RSO
Signature
^> % % s
/:.^f Y^. s
•/•/ ^
Yi%
1~lo IL Ye-.
2) Were all of the RWPs that were reviewed complete?
Comments:
Yes No >£1
3) Was supporting documentation (i.e. Safe Work Permits and Confined Space Permits) attached to the RWPs?
Comments: y ^ .i ^ y Yes No><r^
^.^/iZ..^' r>/n
U:\rad\COMMON\Uranium milisM le(2)UTl900479 Denison Mines - White Mesa UMill\HP Inspection modules\2010\hispection Modules\RADMOD-RWP-02.doc
n^if RWPs lined out or marked with an 4) Were non-applicable items on^c RWPs lined out or marked with an Yes VcT No_
Comments: 7 ^ x
5) Does the RWP form adequately cover all of the informafion required? Yes No
Comments: ; ^
/•'•'-. • 6) On average, how much fime does the RSO and Radiation Safety staff has to review requests for RWPs
before they approve them?
Comments:
7) How does the RSO/Radiation Safety staff verify the RWPs are being followed?
Comments: • ^ ^ .jf //
iy^^'<^ ^^^^ />5t--.?-s /e- /pc^i--^ j.^ I i V^Y/(^^
—,
8) Section 5.1 of the Mills Radiafion Protection manual says "The receipt, handling or processing of any
altemate feed material, which has been determined by the RSO, not to within existing operafing procedure".
What is the Altemate feed being processed in the Altemate feed Circuit?
Comments: / ^
l A f'^^^ ' > ^^^^ "^Op /^^.-^.^ y^A <C S^P
9) If no SOP for the altemate feed is there a RWP? Yes No_
Comments: , A
iMi. ^
10) Observe the Altemate Feed Circuit are the employees following the SOP or RWP for the material they are
processing? Yes No
Comments: , ^-i
U:\rad\COMMON\Uraniuni millsM le(2)UTI900479 Denison Mines - White Mesa UMill\HP Inspection iTiodules\201 OMnspection Modules\RADMOD-RWP-02.doc
11) Identify a RWP that is being worked under during the inspection and go to that work site and verify that the
RWP is being followed. What are the details of the job?
Comments: y
12) What precaufions are necessary to reduce exposure to Uranium and daughters
Comments: ^
P aP YF.^ ff^M}^^ Yy/p^ ^ ^ Pl/^.^ ; 4'^ ^.y>P6 . pP<
13) What are the monitoring requirements for the RWP?
Comments: . .
Y-r^-^:^^ AY/CY.^^ /^r-jyiM'-
14) Are the following being done for the RWP being observed?
Yes No
Monitoring requirements being done?
Mill personnel wearing the appropriate PPE?
Other ALARA pracfices being done?
Was there specialized training documented?
Comments" ^— y;
APPh P/P P'j^ /P.^ ... l-n .^ P-—
15) Are RWP jobs being documented on the daily and weekly inspecfions?
Comments:
16) Any non-compliance issues observed?
Comments:
U:\rad\COMMON\Uranium millsM le(2)UTI 900479 Denison Mines - White Mesa UMill\HP hispection modules\201 OMnspection ModulesMlADMOD-RWP-02.doc
17) If yes, was it corrected and ho^Pl-as it corrected?
Comments: ,
MP-
Daily, Weekly and Monthlv Inspections
18) Review the Daily inspections for the last year. Were any non-compliance issues identified?
Comments: i ^
—dPl^ X^b./n .- ^^-^^Z..,,,, C4>_ y<,C'.. .z,3: }yi,^ , PP^P
19) How was the non-compliance issue resolved?
Comments:
20) Were there any re-occurrences?
Comments: J
/PJh-
21) Review the Weekly inspecfions for the last year. Were any non-compliance issues identified?
Comments: ^ ^
'r>^ /-u..^ 7^ .Up'Y Ai-j^.'P 4 ^^.y r P/^-^j^ '^^^P.-
22) How was the non-compliance issue resolved?
Comments: / ^ ' PP
23) Were there any re-occurrences?
Comments: ,
7^
U:\rad\C0MM0N\Uranium millsM le(2)UTI900479 Denison Mines - While Mesa UMill\HP Inspeclion modulesVZO I OMnspection Modules\RADMOD-RWP-02.doc
24) Review the monthly Reports Mm.he following being documented?
Yes No
A summary ofthe recent personnel exposure data, including
bioassay and time-weighted calculations
A summary ofall pertinent radiation survey records
A discussion ofany trends or deviations from the radiation
protecfion and ALARA programs, including an evaluation of the
adequacy ofthe implementafion of license conditions regarding
radiation protecfion and ALARA
A descripfion of unresolved problems and the proposed correcfive
measures
Comments:
25) Review the Monthly reports for the last year. Were any non-compliance issues identified?
Comments:
Aht-t 'i^P^, '!7/P^.
26) How was the non-compliance issue resolved?
Comments:
27) Were there any re-occurrences?
Comments:
28) Were any non-compliance issues need to be reported to the State?
Comments:
29) Were all issues reported?
Comments:^^^
U:\rad\COMMON\Uranium millsM I e(2)UTl 900479 Denison Mines - While Mesa UMill\HP hispection modules\201 OMnspection Modules\RADMOD-RWP-02.doc
enl^( 30) Determine the PPE requirememPfor each Department/Mill Location frOTPihe RSO. Then during mill tour,
Department/Location PPE Requiremen ts (check applicable)
Laboratory
PPE Observed Y/N
Hard Hats Tyvek Disp. Gloves •^yeiP Laboratory
PPE Observed Y/N Safety Glasses '^llearing Face Shields
Laboratory
PPE Observed Y/N
Safety Boots !/ ^Respirators y "^Rubber Suits
Laboratory
PPE Observed Y/N
Rubber Boots Lab Coats y Other
Laboratory
PPE Observed Y/N
Coveralls Gloves AlYi/A t7
Mill
PPE Observed Y/N
Hard Hats 1/ ^yvek i/ '^Disp. Gloves Mill
PPE Observed Y/N Safety Glasses 'Hearing 1/ '^Face Shields
Mill
PPE Observed Y/N
Safety Boots V ' Respirators y -Rubber Suits
Mill
PPE Observed Y/N
Rubber Boots / Lab Coats Other
Mill
PPE Observed Y/N
Coveralls A. ''Gloves
Alternate Feed Circuit
PPE Observed Y/N
Hard Hats V Tyvek y 'Disp. Gloves Alternate Feed Circuit
PPE Observed Y/N Safety Glasses. / Hearing y '^Face Shields y
Alternate Feed Circuit
PPE Observed Y/N
Safety Boots iy ''Respirators "Rubber Suits
Alternate Feed Circuit
PPE Observed Y/N
Rubber Boots i/ '^Lab Coats Other
Alternate Feed Circuit
PPE Observed Y/N
Coveralls ^Gloves
Maintenance
PPE Observed Y/N
Hard Hats Y Tyvek Disp. Gloves Maintenance
PPE Observed Y/N Safety Glasses '^Hearing Face Shields
Maintenance
PPE Observed Y/N
Safety Boots '^Respirators Rubber Suits
Maintenance
PPE Observed Y/N
Rubber Boots Lab Coats Other
Maintenance
PPE Observed Y/N
Coveralls Gloves
Office
PPE Observed Y/N
Hard Hats Tyvek Disp. Gloves Office
PPE Observed Y/N Safety Glasses y 'Hearing Face Shields
Office
PPE Observed Y/N
Safety Boots '^Respirators Rubber Suits
Office
PPE Observed Y/N
Rubber Boots Lab Coats Other
Office
PPE Observed Y/N
Coveralls Gloves
Ore Receiving
PPE Observed Y/N
Hard Hats U '^yvek Disp. Gloves Ore Receiving
PPE Observed Y/N Safety Glasses ^Hearing Face Shields
Ore Receiving
PPE Observed Y/N
Safety Boots >/ "Respirators Rubber Suits
Ore Receiving
PPE Observed Y/N
Rubber Boots Lab Coats Other
Ore Receiving
PPE Observed Y/N
Coveralls Gloves
Warehouse
PPE Observed Y/N
Hard Hats y '^yvek Disp. Gloves Warehouse
PPE Observed Y/N Safety Glasses •Rearing Face Shields
Warehouse
PPE Observed Y/N
Safety Boots y 'iRespirators Rubber Suits
Warehouse
PPE Observed Y/N
Rubber Boots Lab Coats Other
Warehouse
PPE Observed Y/N
Coveralls Gloves
Utility Crew
PPE Observed Y/N
Hard Hats y Ifyvek Disp. Gloves Utility Crew
PPE Observed Y/N Safety Glasses 'Tjearing Face Shields
Utility Crew
PPE Observed Y/N
Safety Boots y Respirators Rubber Suits-*
Utility Crew
PPE Observed Y/N
Rubber Boots Lab Coats Other
Utility Crew
PPE Observed Y/N
Coveralls ^Gloves
Decon Crew
PPE Observed Y/N
Hard Hats Y Jyvek Disp. Gloves Decon Crew
PPE Observed Y/N Safety Glasses y llearing Face Shields
Decon Crew
PPE Observed Y/N
Safety Boots y "^Respirators Rubber Suits
Decon Crew
PPE Observed Y/N
Rubber Boots Lab Coats Other
Decon Crew
PPE Observed Y/N
Coveralls Gloves
U:\rad\COMMON\Uranium millsM le(2)UTl 900479 Denison Mines - White Mesa UMil|\HP Inspeclion modules\201 OMnspection Modules\RADMOD-RWP-02.doc
PERSONAL PROTECTIVE E^PMENT (PPE)
31) Were there any areas in the mill that were observed that did not have an appropriate type or amount of PPE
required? Yes j><^ No
Comments
P^y, :-^..y^ JJ ,y^.'jf P.yt^J^jAOL 5-;^-v/^ .^..P P -^^X^^
" y ^ Y,, y^ 7^ : > y. y .y " / Ps r^f^f Pr-^y7j. f^._:r^ \ /..-^ y'^yiP
32) Where do the mill personnel find out what PPE requirements there are for the department or area that they
are working in?
Comments ^^ . ' ./ , ,
33) How does the Mill verify that the mill personnel are wearing their PPE?
Comments: /
34) How is PPE stored and distributed to employee?
Comments: ^ / / <' / A /
yP-^^P c-yyx^'P-A- I- yPcPJ iy(y^y^/i^.<^y^^.^y
35) When PPE needs to be replaced what is the Mills policy?
Comments: /
FOLLOWUP ITEMS
36) Do a verification Survey on any Intermodal Containers that may be onsite
Comments: , ^
p^
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Dor,o 7 of 0
37) Observe 1 le(2) material bein^Rposed of in the tailing cells
Comments:
PPP.'^'y:> ^•/j'^,..<;. JS^^P P ^ Xi^^ fe? ysP yyP^
P..-'^*^ PP^l j'y[ :^',^^P -7&,,fi' yP^L^ r .•• ^x. ^-J!--, ^ 'iT? /'T^''-^ ^
P y.rY. Ay, ^ c/ / ^^.^ "
38) Observe employees exifing the Restricted Area are the properly surveying themselves?
Comments:
/yJ-^y/y^ ^JhwyPiL .^c.-^/T^ 'P A'S^pcPP ^(Py, — .>,P PP /\y-ye^
-r
39) During the Mill Tour look for yellowcake and see if it is being cleanup.
Comments:
7)J A/P ^ ^a/P/^.. ,/^P.>. -P /^///
y,
ipJpo^s^yL yy^yT PiL U^j^y^:^P^ ^ <^ytZ^/{
U;\rad\COMMON\Uranium millsM le(2)UT 1900479 Denison Mines - White Mesa UMill\HP hspeclion modules\201 OMnspection Modules\RADMOD.-RWP-02.doc
Dnnn e of e
A. ^ ^ ,.s/yp3^ ^-^^^
RADIATION WORK PERMIT
RWP# 3Pk^
Requestor -^ .-d^ R,.,.4.U-VV
Job Location <?r^ fi^..,,.>
Job Description
Radiological Monitoring and Sampling
At Start ty^ Intermitte Continuous
^L^Dust (B) Radon Daughters (C) Beta-Gamma"
((5><^ross Alpha (E) Removable Alpha
Breathing Zon^_^ ____ Minutes Ran
Bioassay (^^-^ No
At End
pCi
Personnel leaving
Protective Equipment
Rubber Gloves
Coveralls /TI., ,^VS
Respirator Fit Testing
Rubber boots
Hoods
Rubber suits
Local Ventilation
Name Type1/^S) Irritant Smoke Size Proper Fit Worn Fitted by (Initials)
fol.\ fa^ie^ y >^
y
.y , /La
ALARA Considerations
Estimated Job Duration:
Standby Workers NA
Cleanup ... \\ ,^\,^
Estimated exposure RPWI.-.. i ,.; .k..
APPROVEDBY:
iJ4^il?,4L»,L ^.Tv^r^U.Li Number of Workers_
Showers Required — Time Limitations _
Date
Name In Out In Out In Out In Out Total Time
•rci/v ^^^^ fiyy-
(iu U '<^-t b
.-9.'J/7 '3'/(7
Job Status: Completed_
Permit Terminated
Reviewed By
Changed
Date
Cancelled
Time
Date
.By
'1
No.: PBL-21
•
DENISON MINES (USA) CORP.^
STANDARD OPERATING PROCEDlMs Rev. No.: R-l •
DENISON MINES (USA) CORP.^
STANDARD OPERATING PROCEDlMs Page 1 of
Date: June 24, 2009 Title: UF4 Processing 25
STANDARD OPERATING PROCEDURES FOR UF4 PROCESSING
Overview
The following standard operating procedures ("SOP") are for the processing of the UF4
altemate feed material. These operating procedures are summarized by nodes with the
hazards, PPE, cautionary statements and operating instructions for each node. A node is
a phase of recovery in the overall process and is indicated by graphic presentation of the
process flow. A block flow diagram of the overall process is set out on the following
page.
There are general considerations that are applicable to all process nodes. They are:
• Lines and Pumps
All lines, pumps and valves must be used according to specific operating
instructions that will be issued as required during process evaluations and
recovery.
• Specific Operatmg Instructions
Specific operating instmctions apply to each process node based upon the
metallurgical requirements necessary for recovery of an on-specification product.
These instmctions will change periodically after operating process and parameters
have been determined.
• Hazard Assessment Worksheet
Each hazard assessment worksheet identifies hazardous parameters for each node,
such as operating temperature, pressure and radioactive content of each stream.
The overall hazard rating is based on quantity of chemical, phase of the chemical
(gas, solid, and liquid) and the MSDS health rating for each chemical. The
overall health rating is the sum of the three ratings.
• Persoimel Protective Equipment ("PPE")
PPE is identified on each node and is accompanied by cautionary statements of
each important hazardous chemical.
This information will be presented to all operations personnel, and any questions
regarding this mformation will be answered.
This SOP may be modified as necessary by a Radiation Work Permit ("RWP") which
would establish new procedures and requirements during the processing of the UF4
altemate feed material.
No.: PBL-21
Rev. No.: R-l
Date: June 24, 2009
DENISON MINES (USA) CORP. _
STAKT)ARD OPERATING PROCEDURES Page 2 of
Title: UF4 Processing 25
Block Flow Diagram of Overall Process
BartBh Solids
To Tailings
1
To Nomnal
Yellowcake
Precipitation Product
Holding Tank
No.:PBL-21
#
DENISON MINES (USA) CORP^
STANDARD OPERATING PROCEDlWs Rev. No.: R-l #
DENISON MINES (USA) CORP^
STANDARD OPERATING PROCEDlWs Page 3 of
Date: June 24, 2009 Title: UF4 Processing 25
NODE #1 - UF4 DRUM DUMPING
Hazard Assessment Worksheet
Equipment Component UF4 Drum Dumping Node
Individual Equipment No.
Parameter Process Material in Component
Process Flow Diagram Uranium
Tetra-
fluoride
Sodium
Carbonate
Hydrogen
Peroxide
Quantity in Equipment (lb) 1600 8,300 250
Concentration (%) 70-90 10 50
Flashpoint, °F — —
TLV-TWA mg/m'
STEL mg/m' —
Radioactivity, pCi/g 484,263 —
Temperature, °C 25-80 25-80
Pressure, psig — ~
Health Rating 1 1 2
Hazard Rating Rad 0 Oxy
Assessment Description: The UF4 material is a dry solid and can become airbome easily.
Also, the UF4 material contains fluorides which can become highly corrosive if allowed
to come in contact with acids. The material should be left undisturbed as much as
possible once the drums are opened until the drums are loaded in the drum dumper. The
UF4 material is also radioactive and you must follow established health physics
controls. If any UF4 gets on your clothing or skin, wash it off with generoiis
amounts of soap and water.
No.: PBL-21
Rev. No.: R-l
Date: June 24, 2009
DENISON MINES (USA) CORP.
STANDARD OPERATING PROCEDUR:
Title: IJF4 Piocessing
ORES Page 4 of
25
Steam -i
H,0
NajCOs
OO
NajCOj Make-
up Tank
Steam
H,0
Submerged Drum
Dumping Station
Digestion /
Precipitation
Tank
Operating Instructions
The UF4 drums must be kept sealed or covered as much as possible until all process
components are ready for dumping the drums.
• Make sure you are familiar with the MSDS sheets for the UF4 material and the
sodium carbonate, copies of which are attached to this procedure.
• Make a safety inspection of all lines and equipment.
o Inspect lines for leaks or seeps.
o Inspect safety showers and eyewash fountains.
This processing of UF4 consumes significant volumes of sodium carbonate (soda ash)
solution. A batch of the sodium carbonate (soda ash) solution is made up as follows:
• Add a volume ofi water to the sodium carbonate make-up tank as instructed by
your supervisor.
• Tura on agitation in the tank and add steam as needed to raise the water
temperature as instructed by your supervisor (normally about 80°C).
• Raise a supersack of soda ash into position and gradually add soda ash to the
stirred water in the tank. Repeat with additional supersacks of soda ash until you
have added the amount of soda ash as instructed by your supervisor.
i)
No.: PBL-21
•
DENISON MINES (USA) CORPj^
STANDARD OPERATING PROCEDlMs Rev. No.: R-l •
DENISON MINES (USA) CORPj^
STANDARD OPERATING PROCEDlMs Page 5 of
Date: June 24, 2009 Title: UF4 Processing 25
• Continue stirring and heating the contents of the tank as instructed by your
supervisor until all of the soda ash has dissolved.
• Transfer a volume of sodium carbonate (soda ash) solution from the make up tank
to the drum dumping station as instmcted by your supervisor.
• Add a volume of hydrogen peroxide solution to the drum dumping station as
instmcted by your supervisor.
The procedure for dumping the UF4 drums is as follows:
• Put on die PPE specified in the applicable RWP-or as otherwise specified by die
Radiation Safety Officer. .
• Tum on the drum dumping station and the weigh scale.
• Place a UF4 dmm in position for handling.
• Weigh the drum and record the drum weight.
• Undo the dmm lid carefully and report any unusual conditions to your supervisor.
• Examine the contents of the drum. If the contents of the dmm have solidified to
the extent that the material cannot be easily removed from the dmm, then refasten
the lid and set the dmm aside for special handling at a later date. For all other
dmms, proceed with the following steps.
• Place the dmm in die drum dumper. Make sure the dmm is properly secured and
make sure all personnel are clear of the dmm dumper mechanisms. Then actuate
the dmm dumper and dump its contents into the bath portion of the dumping
station while the dmm is submerged in the bath.
• Set the valves in the appropriate positions to re-circulate the contents of the badi
and start the discharge pump.
e Operate water jets and other features of the dumping station until the dnmi has
been completely emptied. Then actuate the dumping mechanism to remove the
empty dmm from the bath.
• Inspect the dmm to assure it is empty and then remove the empty dmm from the
process area as instmcted by your supervisor. If the drum is not empty, repeat
No.: PBL-21 ^ DENISON MINES (USA) CORP. ^
Rev. No.: R-l STANDARD OPERATING PROCEDURES Page 8 of
Date: June 24, 2009 Title: IJF4 Processing 25
Steam
CO
H,0,
CO
Na2C03 Digestion /
Make-Up Precipitation
Tank Tank
Operating Instructions
This node deals witli digesting the UF4 material in sodium carbonate (soda
ash) solution at 80°C for about 4 hours.
• Make a safety inspection of all lines and equipment.
o Inspect lines for leaks or seeps.
o Inspect safety showers and eyewash fountains
• As the digestion tank is being filled from the drum dumping station,
once the level of slurry in the digestion tank is appropriate for starting
agitation without causing splashing or spillage - then start agitation.
Continue receiving slurry from the dmm dumping station until a full
batch has been received.
• Add the required volume of hydrogen peroxide solution to the
digestion tank as instmcted by your supervisor. Wear appropriate PPE
for handling hydrogen peroxide, as specified below.
• Add steam to the contents of the tank until the contents reach 80°C.
Continue adding steam as needed to maintain this temperature.
• Continue agitation of the tank contents at 80°C for 4 hours to complete
the necessary digestion.
• At the end of the digestion time, measure the volume of final digestion
solution in the tank and take a sample of the contents of the tank and
No.: PBL-21
Rev. No.: R-l
Date: June 24, 2009
DENISON MINES (USA) CORR^JT
STANDARD OPERATING PROCEDL^Ss
Tide: UF4 Piocessing
Page 9 of
25
place the sample in an appropriately marked container. Make sure this
sample container is marked clearly witii the batch number, the sample
identification and the date. Make sure this sample is collected by
laboratory technicians and transported to the laboratory.
Whenever working in, around or on this process you must avoid
splashing and any contact with the skin and you must wear PPE which
includes at a mininium, hard hat, coveralls, mbber boots and gloves,
safety glasses witii side shields, and .may include respiratory
protection, a face shield or safety^ goggles, all as specified in the
applicable RWP or as otherwise specified by the Radiation Safety,
Officer.
1
No.: PBL-21 ^ DENISON MINES (USA) CORP. ^
Rev. No.: R-1 STANDARD OPERATING PROCEDURES Page 10 of
Date: June 24, 2009 Tide: UF4 Processing 25
NODE #3 - NaOH PRECIPITATION NODE
Hazard Assessment Worksheet
Equipment Component
Individual Equipment No.
NaOH Precipitation Node
Parameter per Tank Process Material in Component
Process Flow Diagram Uranium Sodium NaOH Diatomaceous Process Flow Diagram
Carbonate Earth Filter
Aid
Quantity in Equipment (lb) 1200 8,300 6,800 3,000
Concentration (%) 1.4 10 50 3
Flashpoint, °F — — —
TLV-TWA mg/m' — — -
STEL mg/m' — — —
Radioactivity, pCi/g 484,242 — — —
Temperature, °C 70 70 Amb Amb
Pressure, psig — — — —
Health Rafing 1 1 3 0
Health Hazard Rad 0 Cor 0
Assessment Description: A uranium-rich precipitate is formed by NaOH addition to the
solution from the carbonate digestion of the UF4 material in this processing step. The
liquid in the tank is strongly basic. Any splashing or contact with the skin should be
avoided. These materials can cause skin and eye burns. The solution and the
precipitate that is formed are also radioactive and you must follow established
health physics controls. If any of the solution or precipitate gets on you, wash it off
with generous amounts of soap and water.
No.: PBL-21
Rev. No.: R-l
Date: June 24, 2009
I ll I II III I I lil II III I II II idH
STANDARD OPERATING PR0CEDIJKE5
Title: UF4 Processing
Page 11 of
25
Digestion/
Precipitation
Tank
1
Operating Instructions
This node deals with formation of a uranium-rich precipitate by addition of
NaOH to the final solution from the carbonate digestion of the UF4 material.
• This precipitation processing step will be done in the same tank in
which the carbonate digestion was performed.
• Make a safety inspection of all lines and equipment.
6 Inspect lines for leaks or seeps.
o Inspect safety showers and eyewash fountains
• Continue agitation of the final solution from carbonate digestion of the
UF4 material. Add steam, if necessary, to maintain the contents of the
digestion/precipitation tank at least at 70°C (158°F).
• Make'sure you are wearing all appropriate PPE for handling 50%
NaOH (caustic) solution, as specified below.
• To the agitated contents of the digestion/precipitation tank carefully
add 50% NaOH (caustic) solution until the pH of the contents of the
tank reaches at least 13.0 as instmcted by your supervisor. Measure
the pH of the tank contents with pH paper obtained from the lab. Do
not measure the pH using an ordinary pH meter and probe - these may
not give correct pH readings in this solution.
• After the contents of the tank reach the target pH, continue for 4 hours
to agitate the tank contents at the target temperature and continue to
No.: PBL-21
Rev. No.: R-l
Date: June 24, 2009
DENISON MINES (USA) CORP.
STANDARD OPERATING PROCED
Tide: UF4 Piocessing
Page 12 of
25
carefully add small volumes of the 50% NaOH solution to the tanic as
necessary to maintain the target pH.
After four hours the precipitation reaction should be complete. At this
point add to the sluiry in the digestion/precipitation tank the amount of
filter aid (diatomaceous earth) as instmcted by your supervisor. Make
sure you are wearing the appropriate respirator protection as
determined by the RSO whenever handling or working in the vicinity
of filter aid in its dry condition. Then adjust the necessary valves, tuiTi
on the pump, and transfer the contents of the digestion/precipitation
tank to the filter feed tank.
After the batch of material has been transferred as completely as
practical from the digestion/precipitation tank to the filter feed tank
then make sure the digestion/precipitation tank agitator is tumed off
and that all valves, pumps, etc. have been retumed to the proper
settings for starting handling of the next batch of UF4 slurry from the
drum dumping station.
Whenever working in, around or on this process you must avoid
splashing and any contact with the skin and YOU MUST wear PPE
which includes at a minimum, hard hat, coveralls, rubber boots and
gloves, safety glasses with side shields, and may include respiratory
protection, a face shield or safety goggles, all as specified in the
applicable RWP or as otherwise specified by the Radiation Safety
Officer.
)
No.: PBL-21 DENISON MINES (USA) CORP«
STANDARD OPERATING PRGCEDUIES Rev. No.: R-l
DENISON MINES (USA) CORP«
STANDARD OPERATING PRGCEDUIES Page 13 of
Date: June 24, 2009 Title: UF4 Processing 25
NODE #4 - NaOH PRECIPITATE FILTRATION NODE
Hazard Assessment Worksheet
Equipment Component NaOH Precipitate Filtration Node
Individual Equipment No.
Parameter per Tank Process Material in Component
Process Flow Diagram Uranium Sodium
Carbonate
NaOH Diatomaceous
Earth Filter Aid
Quantity in Equipment (lb) 1200 8,300 6,800 3,000
Concentration (%) 1.4 10 8 3
Flashpoint, °F — — —
TLV-TWA mg/m' — — —
STEL mg/m' — —
Radioactivity, pCi/g 484,242 — — —
Temperature, °C 70 70 70 Amb.
Pressure, psig — — .r-~
Health Rating 1 1 3 0
Health Hazard Rad 0 Cor 0
Assessment Description: The uranium-rich precipitate formed by NaOH addition to the
solution from the carbonate digestion of the UF4 material is separated from the solution
by pressure filtration. Make sure all pressurized lines, connections and fittings are in
good condition and not leaking. The liquid in the tank is strongly basic. Any splashing
or contact with the skin should be avoided. The chemicals in the liquid can cause skin
and eye burns. The solution ahd the precipitate are also radioactive and you must
follow established health physics controls. If any of the solution or precipitate gets
on you, wash it off with generous amounts of soap and water. The filter aid material
is dusty in the dry condition and you must avoid breathing the dust.
No.: PBL-21
Rev. No.: R-l
Date: June 24, 2009
DENISON MIMES (USA) CORP.
STANDARD OPERATING PROCEDURES
Title: UF4 Processing
To Tails
- Cell 1
Filter Cake Filter Cake Filter Aid
Addition Tank Re-Pulp
Tank 1
Filter Aid
Addition Tank
Page 14 of
25
Y
c o
CO
Filter Cake
Acid Re-
Dissolution
Tank
1
Operating Instructions
This node deals with the pressure filtration processing step to recover the
uranium-rich precipitate formed by NaOH addition to the solution from tiie
carbonate digestion of the UF4 material.
• Make a safety inspection of all lines and equipment.
o Inspect lines for leaks or seeps.
o Inspect safety showers and eyewash fountains
o Inspect the filter to make sure it has been fully dumped,
cleaned, and prepared to receive fresh feed material.
• If body feed filter aid has already been added in the
digestion/precipitation tank, omit the first two steps of this SOP Node.
Otherwise, open or close the necessary valves and turn on the
necessary pumps to circulate the slurry from the filter feed tank
through the filter aid addition tank and back to the filter feed tank.
Tum on agitation in the filter aid addition tank. Add and mix into the
contents of the filter aid addition tank the amount and type of body
feed filter aid as instructed by your supervisor. Make sure you are
wearing the appropriate respirator as determined by the Radiation
Safety Officer whenever handling or working in the vicinity of filter
aid in its dry condition.
)
.)
No.: PBL-21
Rev. No.: R-l
Date: June 24, 2009
DENISON MINES (USA) CORPf _
STANDARD OPERATING PROCEDURES
Tide: UF4 Processing
Page 15 of
25
• When all body feed filter aid has been added, turn off appropriate
pumps and adjust the appropriate valves to shut off flow from tiie filter
feed tank to the filter aid addition tank. Complete transfer of all slurry
from the filter aid addition tank to the filter feed tank, using a small
volume of water as necessary to rinse out the tank. Then tmn off the
pump and adjust the valves to shut off flow from the filter aid addition
tank to the filter feed tank.
• Add water to the filter aid addition tank for pre-coating the pressure
filter according to instructions from your supervisor. Start agitation of
the tank and then add pre-coat filter aid to the tank according to
instructions from your supervisor. Mix the contents of the tank
thoroughly. Make sure you are wearing the appropriate respirator as
determined by the Radiation Safety Officer whenever handling or
working in the vicinity of filter aid in its dry condition.
• Adjust all necessary valves and tum on the pump to transfer pre-coat
filter aid slurry from the filter aid addition tank to the filter press.
Pump the entire contents of the filter aid addition tank through the
filter press. Then turii off tiie pump and adjust all necessary valves to
leave the pre-coated filter press filled with water under some pressure.
• Adjust all necessary valves and tum on the pump from the filter feed
tank to the filter press. Recycle filtrate back to the filter feed tank until
the solution clears and then adjust the appropriate valves to send all
barren filtrate to the filtrate and wash surge tank. Pump the contents of
the filter feed tank through the filter press until the tank is empty or tiie
pressuris or flow rate indicates the filter press chambers are full of filter
cake.
• Tum off the pump from the filter feed tank, adjust the necessary
valves, and run wash water through the filter press according to
instmctions from your supervisor. Send the filter discharge to the
filtrate and wash surge tank.
• Shut off the wash water, adjust the appropriate valves, and mn
compressed air through the filter press according to instmctions from
your supervisor. Send the filter discharge liquid to the filtrate and
wash surge tank.
• When the filter cake has been adequately dried by the compressed air,
shut off the air flow and depressurize the filter press.
No.: PBL-21 ^ DENISON MINES (USA) CORP.^
Rev. No.: R-l STANDARD OPERATING PROCEDURES Page 16 of
Date: June 24, 2009 Title: UF4 Processing 25
Tum on the screw conveyor system under the filter press, open the
filter, and dump and transfer all filter cake to the filter cake re-pulp
tank 1.
Add water to the filter cake re-pulp tank 1 as instructed by your
supervisor and agitate the contents of the tank until tiie filter cake is
fully re-pulped. Adjust appropriate valves and tum on the pump to
transfer the re-pulped filter cake slurry to the filter cake acid re-
dissolution tank according to instmctions from your supervisor.
Clean the filter press, close it up, and prepare it for its next filtration
cycle.
Repeat pre-coating the filter, filtering the contents of the filter feed
tank, and dumping and re-pulping the filter cake and transferring it to
the filter cake acid re-dissolution tank until the filter feed tank is
empty.
Make sure the volume in the filtrate and wash surge tank is measured
and recorded and make sure a sample of the contents of the tank is
placed in an appropriately marked sample container for analysis by the
lab. Then send the contents of the filtrate and wash surge tank to
tailings.
Whenever working in, around or on this process you must avoid
splashing and any contact with the skin and YOU MUST wear PPE
which includes at a minimum, hard hat, coveralls, mbber boots and
gloves, safety glasses with side shields, and may include respiratory
protection,, a face shield or safety goggles, all as specified in the
applicable RWP or as otherwise specified by the Radiation Safety
Officer.
Always keep your work area clean and ensure your work area is free
of obstmctions.
No.: PBL-21
•
DENISON MINES (USA) CORP^
STANDARD OPERATING PROCEDllBs Rev. No.: R-l •
DENISON MINES (USA) CORP^
STANDARD OPERATING PROCEDllBs Page 17 of
Date: June 24, 2009 Title: UF4 Processing 25
NODE #5 - FILTER CAKE ACID RE-DISSOLUTION NODE
Hazard Assessment Worksheet
Equipment Component Filter Cake Acid Re-Dissolution Node
Individual Equipment No.
O
Parameter per Tank Process Material in Component
Process Flow Diagram Uranium Sulfuric Acid Sodium
Chlorate
Quantity m Equipment (lb) 1200 1250 150
Concentration (%) 1-8 93 50
Flashpoint, °F — —
TLV-TWA ppm — ,—
STEL ppm — —
Radioactivity, pCi/g 484,242 — — —
Temperature, °C 25-40 25-40
Pressure, psig — 0-100 — —
Health Ratmg 1 3 1
Health Hazard Rad Cor Oxy
Assessment Description: The re-pulped filter cake of basic uranium-rich precipitate and
the acidic solution in which it will be digested should be handled with caution. Any
splashing or contact with the skin should be avoided. The acidic chemicals in the liquid
can cause skin and eye burns. The solution and the filter cake are also radioactive
and you must follow established health physics controls. If any of the solution or
filter cake gets on you, wash it off with generous amounts of soap and water.
• )
No.: PBL-21
Rev. No.: R-l
Date: June 24, 2009
DENISON MINES (USA) CORR^fc"
STANDARD OPERATING PROCEDURES
Title: UF4 Processing
Page 18 of
25
H2SO4
Steam
NaClO,
Filter Cake Acid
Re-Dissolution
Tank
Operating Instructions
This node deals with the acid digestion of re-pulped uranium-rich filter cake.
• Make a safety inspection of all equipment.
o Inspect safety showers and eyewash fountains
o Inspect valves and fittings in the acid line.
• As the slurry of re-pulped filter cake is being transferred to the filter
cake acid re-dissolution tank, turn on agitation in the tank as soon as
the level is sufficient according to your supervisor's instmctions.
• Add water to the contents of the filter cake acid re-dissolution tank
according to instmctions from your supervisor and carefully add
sulfuric acid to bring the pH of the slurry to 2.0 or a lower pH as
instructed by your supervisor. Add a volume of sodium chlorate
solution to the contents of the filter cake acid re-dissolution tank as
instmcted by your supervisor.
• Add steam to bring the contents of the filter cake acid re-dissolution
tank to 40°C or another temperature as instmcted by your supervisor.
Agitate the slurry in the tank at the target temperature and pH for a
time of at least one hour as instmcted by your supervisor, adding
steam and sulfuric acid as needed to maintain these conditions.
No.: PBL-21
Rev. No.: R-l
Date: June 24, 2009
DENISON MINES (USA) CORP^^
STANDARD OPERATING PROCEDlWs
Titie: UF4 Processing
Page 19 of
25
Whenever working in,, around or . on this process, you rnust avoid
splashing and any contact with the skin and YOU MUST wear PPE
which includes at a mininium, hard hat, coveralls, nibber boots and
gloves, safety glasses with side shields, and respiratory protection, a
face shield or safety goggles, all as specified in the applicable RWP or
as otherwise specified by the Radiation Safety Officer.
No.: PBL-21
Rev. No.: R-l
Date: June 24, 2009
DENISON MINES (USA) CORP.
STANDARD OPERATING PROCED
Titie: UF4 Processing
URES Page 20 of
25
NODE #6 - FILTRATION AFTER ACID DIGESTION OF FILTER CAKE NODE
Hazard Assessment Worksheet
Equipment Component Filtration After Acid Digestion of Filter Cake Node
Individual Equipment No.
Parameter Process Material in Component
Process Flow Diagram Uranium Dilute H2SO4 Diatomaceous
Earth Filter
Aid
Quantity in Equipment (lb) 1,200 50 3,000
Concentration (%) 2-4 0.1-0.2 8-10
Flashpoint, °F ~ — —
TLV-TWA mg/m' — —
STEL mg/m' — —
Radioactivity, pCi/g — —
Temperature, "C 40 40 40
Pressure, psig ~ —
Healtii Rating 1 3 0
Hazard Rating Rad Cor 0
Assessment Description: This processing step involves pressure filtration of an acidic
slurry. Any splashing or contact with the skin should be avoided. The acidic chemicals
in the liquid can cause skin and eye burns. The solution and the filter cake are also
radioactive and you must follow established health physics controls. If any of the
solution or filter cake gets on you, wash it off with generous amounts of soap and
water. If any of the filter cake becomes dry, respiration of the dust must be avoided.
The filter press and piping leading to it will be under pressure and should be handled
carefully.
No.: PBL-21
Rev. No.: R-l
Date: June 24, 2009
DENISON MINES (USA) C^ORP^"
STANDARD OPERATING PROCEDURES
Tide: UF4 Processing
Page 21 of
25
Filtrate
and
Wash
Coinp.
Air
H2O
Second Stage
Filter Press
H2O
CO CO
Y
c 0
Filter Cake
CO
Impurity Impurity
Removal Tank Removal Tank
1 , 2
Filter Cake
Re-Pulp
Tank 2
Filter Cake Acid
Re-Dissolution
Tank
H2O Cake Washing
Tank
Operating Instructions
In this processing step the used filter aid is separated from the dissolved
uranium by pressure filtration.
• Make a safety inspection of all lines and equipment.
o Inspect lines for leaks or seeps.
o Inspect the filter feed pump and the filter press for leaks and
proper assembly.
o Inspect safety showers and eyewash foimtains.
• Adjust ail necessaiy valves and tum on the pump from the filter cake
acid re-dissolution tank to the filter press. Recycle filtrate back to the
filter cake acid re-dissolution tank untU the solution clears and then
adjust the appropriate valves to send the filtrate to impurity removal
tank 1 or tank 2. Pump the contents pf the filter cake acid re-
dissolution tank through the filter press until the tank is empty or the
pressure pr flow rate indicates the filter press chanibers are full of filter
cake.
• When the pressure or flow rate indicates the filter press chambers are
full of filter cake, tum off the pump from the filter cake acid re-
dissolution tank, adjust the necessary valves, and run wash water
through the filter press according to instmctions from your supervisor.
Send the filtrate from washing to the same impurity removal tank.
\ )
No.: PBL-21
Rev. No.: R-l
Date: June 24, 2009
DENISON MCNTES (USA) CORP
STANDARD OPERATING PROCED
Titie: UF4 Processing
URES Page 22 of
25
• Wlien the water wash is completed, shut off the wash water, adjust
appropriate valves, and mn compressed air through the filter press
according to instructions from your supervisor. Send any liquid
discharged from the filter press to the same impurity removal tanic.
• When the filter cake has been adequately dried by tiie compressed air,
shut off the air flow and depressurize the filter press.
• Tum on the screw conveyor system under the filter press, open the
filter, and dump and transfer all filter cake to the filter cake re-pulp
tank 2.
• Add water to the filter cake re-pulp tank according to instructions from
your supervisor and agitate contents of the tank until the filter cake is
fully re-pulped. Transfer the re-pulped filter cake slurry to the cake
washing tank according to instmctions from your supervisor.
• Clean the filter press, close it up, and prepare it for its next filtration
cycle.
• Repeat, as needed, steps for filtering the contents of the filter cake acid
re-dissolution tank and dumping and re-pulping and transferring the
filter cake until the filter cake acid re-dissolution tank is empty.
• Transfer the clear supernatant liquid from the cake washing tank back
into the process to recover the contained uranium according to
instmctions from your supervisor. Wash the filter cake solids in the
cake washing tank with water as instructed by your supervisor. Once
the washing of the filter cake solids is sufficient, transfer the solids
from the cake washing tank to tailings according to instructions from
your supervisor.
• Make sure a sample is taken of the underflow solids slurry transferred
from the cake washing tank to tailings.
• Whenever working in, around or on this process you must avoid
splashing and any contact with the skin and YOU MUST wear PPE
which includes at a minimum, hard hat, coveralls, mbber boots and
gloves, safety glasses with Side shields, and may include respiratory
protection, a face shield or safety goggles, all as specified in the
applicable RWP or as otherwise specified by the Radiation Safety
Officer.
Always keep your work area clean and ensure your work area is free
of obstmctions.
No.: PBL-21
Rev. No.: R-l
Date: June 24, 2009
DENISON MINES (USA) CO:
STANDARD OPERATING PROCED
Titie: UF4 Processing
R^^
Page 23 of
25
NODE #7 - IMPURITY REMOVAL NODE
Hazard Assessment Worksheet
Equipment Component Impurity Removal Node
Individual Equipment No.
Parameter Process Material in Component
Process Flow Diagram Uranium H2SO4 Ammonia
Quantity in Equipment (lb) 1200-2400 50-500 100-250
Concentration (%) 2-4 93 100
Flashpoint, °F — — ._
TLV-TWA mg/m' — . 25
STEL mg/m' — 35
Radioactivity, pCi/g .— — ::
Temperature, °C 40 20 20
Pressure, psig
Health Rating 1 3 3
Hazard Rating Rad Cor
Assessment Description: In this step, impurities will be separated from the uranium by
pH adjustment and precipitation, using ammonia, followed by settling and decantation.
REMEMBER Ammonia vapor, fumes and mists are Toxic Atmospheres and cannot
be detected by smell above approximately 100 ppm. IF you smell strong ammonia
fumes you must wear a full face respirator with universal cai-tridges. At high
concentrations your skin and eyes can be burned. The beginning solution and the
precipitate are also radioactive and you must follow established health physics
controls. If any of the solution or precipitate gets on you, wash it off with generous
amounts of soap and water.
No.: PBL-21
Rev. No.: R-l
Date: June 24, 2009
DENISON MINES (USA) CORP.'
STANDARD OPERATING PROCEDURES
Title: UF4 Piocessing
Page 24 of
25
To Tails'
Cell 1 NHsor
H2SO4
Steam Steam
CO CO
NH3 or
H2SO4
Impurity Impurity
Removal Removal
Tank 1 Tank 2
To Normal
Yellowcake
Precipitation
Product
Holding Tank
Operating Instructions
This node deals with the separation of uranium from impurities, by adjusting
pH with ammonia (NH3), to form a precipitate, allowing the precipitate to
settle to the bottom of the tank, and then decanting and pumping away the
clear liquid.
• Make a safety inspection of all lines and equipment.
o Inspect lines and tanks for leaks or seeps,
o Inspect safety showers and eyewash fountains
• Measure contained volume and then tum on the agitator and take a
sample of the tank contents for the impurity removal tank containing
tiie acid digestion liquor that has most recently been clarified by
filtration in the filter press. Place the sample in an appropriately
labeled sample bottle for analysis by the lab.
• Add steam, as necessary, to the contents of the impurity removal tank
according to instmctions from your supervisor to establish and
maintain the target temperature for the tank contents. Add ammonia to
the contents of the impurity removal tank according to instructions
from your supervisor. Continue adding ammonia until the contents of
the tank reach and remain at the target pH, as instructed by your
supervisor, and then continue agitation for an additional 30 minutes.
• Tum off the agitator in the impurity removal tank and allow the
precipitate to settle according to instmctions from your supervisor.
J
No.: PBL-21
Rev. No.: R-l
Date: June 24, 2009
DENISON MINES (USA) CORP
STANDARD OPERATING PROCEDU
Titie: UF4 Processing
Page 25 of
25
Depending on the impurity being removed from the uranium, the
uranium may be contained in either the precipitate or in tiie
supernatant liquid. Once your supervisor has determined that the
precipitate in the impurity removal tank has settled sufficientiy, begin
decanting the clear supernatant liquid from the tank.
If tiie uranium is in the precipitate, then transfer the decanted liquid to
tailings as instmcted by your supervisor. Be sure to take a sample of
the decanted liquid and record and report the volume of decanted
liquid. After the liquid is completely decanted as instmcted by youi"
supervisor, add water to wash the precipitate as instructed by your
supervisor and agitate, settle and decant again. After washing the
precipitate, add water and sulfuric acid to the precipitate as instructed
by your supervisor and agitate until the uranium is all re-dissolved.
Then either conduct other impurity removal steps on the liquor or
transfer it to the product holding tank.
If the uranium is in the decanted liquid, tiien transfer the liquid to the
other impurity removal tank if addition impurity removal is needed, or
else transfer the liquid to the product holding tank. Once the decanting
is complete, add water, agitate, settle and decant again to wash the
precipitate, sending the liquid removed to the same tank as previously.
If tiie washed precipitate is sufficiently low in uranium, transfer it to
tailings as instructed by your supervisor. Otherwise, send the
precipitate to re-processing as instructed by your supervisor.
Once impurities have been sufficiently removed and the liquor has
accumulated sufficiently in the product holding tank, transfer the
contents of the product holding tank slowly to the normal yellowcake
precipitation area of the plant. Each time a transfer from tiiis tank
occurs, record and report the volume transferred and take a sample of
the liquor transferred in a properly marked sample container.
Whenever working in, aroimd or on this process YOU MUST wear
PPE which includes at a minimum, hard hat, coveralls, mbber boots
and gloves, safety glasses with side shields, and may include
respiratory protection, a face shield or safety goggles, all as specified
in the applicable RWP or as otherwise specified by the Radiation
Safety Officer.