HomeMy WebLinkAboutDRC-2011-007451_12 - 0901a0688027e86fAPPENDIX G
PRELIMINARY MILL DECOMMISSIONING REPORT
WHITE MESA MILL
SEPTEMBER 2011
PREPARED BY
MWH AMERICAS
3665 JFK PARKWAY, BLDG 1, SUITE 206
FORT COLLINS, CO 80525
Denison Mines (USA) Corp.
WHITE MESA MILL
Preliminary Mill
Decommissioning Plan
September 2011
3665 JFK Parkway
Suite 206
Fort Collins, CO USA
Preliminary Mill Decommissioning Plan
Denison Mines Corp. MWH Americas, Inc.
i September 2011
TABLE OF CONTENTS
1.0 SPECIAL PROVISIONS ................................................................................................... 1
1.1 Scope of Document ............................................................................................... 1
1.2 Definitions .............................................................................................................. 1
1.3 Decommissioning Goals and Implementation Strategy ......................................... 1
1.4 Scope of Work ....................................................................................................... 2
2.0 GENERAL REQUIREMENTS AND PROCEDURES ........................................................ 4
2.1 General .................................................................................................................. 4
2.2 Applicable Regulations and Standards ................................................................. 4
2.3 Health and Safety Requirements .......................................................................... 4
2.4 Environmental Requirements ................................................................................ 4
2.4.1 Contractor Activities ................................................................................... 4
2.4.2 Environmental Monitoring .......................................................................... 5
2.5 Medical Emergency Procedures............................................................................ 5
2.5.1 Level One Priority ...................................................................................... 5
2.5.2 Level Two Priority ...................................................................................... 5
2.6 Water and Contaminant Management .................................................................. 6
2.6.1 Runon/Runoff Control ................................................................................ 6
2.6.2 Residue Management ................................................................................ 6
2.6.3 Contamination Control ............................................................................... 7
2.6.4 Dust Control ............................................................................................... 7
2.6.5 Historical and Archaeological Considerations ........................................... 7
3.0 SITE REQUIREMENTS AND PROCEDURES ................................................................. 9
3.1 General .................................................................................................................. 9
3.2 Site Location .......................................................................................................... 9
3.3 Climate and Soil Conditions .................................................................................. 9
3.4 Site Layout and Facilities ...................................................................................... 9
3.4.1 Operation History ....................................................................................... 9
3.4.2 Access and Security ................................................................................ 10
3.4.3 Utilities ..................................................................................................... 10
3.4.4 Sanitation Facilities .................................................................................. 10
3.4.5 Fire Protection ......................................................................................... 10
3.5 Personal Protection Requirements ...................................................................... 10
3.6 Occupational Monitoring Requirements .............................................................. 11
3.7 Operational Issues .............................................................................................. 11
3.8 Training ............................................................................................................... 11
4.0 EQUIPMENT SALVAGE ................................................................................................ 13
4.1 General ................................................................................................................ 13
4.2 Decontamination ................................................................................................. 13
4.3 Decontamination Procedures .............................................................................. 13
4.4 Decontamination Areas ....................................................................................... 13
5.0 PRE-DEMOLITION ACTIVITIES .................................................................................... 14
5.1 General ................................................................................................................ 14
5.2 Area Evaluation Process ..................................................................................... 14
5.3 General Preparation Work ................................................................................... 15
5.3.1 Circuit Cleanup ........................................................................................ 15
Preliminary Mill Decommissioning Plan
Denison Mines Corp. MWH Americas, Inc.
ii September 2011
5.3.2 Laboratory Reagents ............................................................................... 15
5.3.3 Oils and Lubricants .................................................................................. 15
5.3.4 Asbestos .................................................................................................. 15
5.4 Process Area Preparation ................................................................................... 15
5.5 Staging and Storage Areas ................................................................................. 16
6.0 PROCESS AREA DEMOLITION .................................................................................... 17
6.1 General Description ............................................................................................. 17
6.2 Mill Area .............................................................................................................. 17
6.3 Demolition Strategy ............................................................................................. 18
6.3.1 Staging of Decommissioning ................................................................... 18
6.3.2 Remote Demolition .................................................................................. 18
6.3.3 Demolition Equipment .............................................................................. 18
6.4 Utilities Management ........................................................................................... 19
6.4.1 Liquefied Natural Gas and Propane Systems Disconnect ....................... 19
6.4.2 Electrical System Disconnect .................................................................. 20
6.4.3 Water System Disconnect ....................................................................... 20
6.4.4 Phone System ......................................................................................... 20
6.5 Surface Structure Removal ................................................................................. 20
6.6 Concrete Removal ............................................................................................... 20
6.7 Utility Removal .................................................................................................... 21
6.8 Miscellaneous Site-Wide Facilities ...................................................................... 21
6.9 Contaminated soils .............................................................................................. 21
6.10 Windblown Contamination ................................................................................... 22
6.11 Preparation of demolition debris for Disposal ...................................................... 22
7.0 REGRADING AND REVEGETATION ............................................................................ 23
7.1 Regrading ............................................................................................................ 23
7.2 Revegetation ....................................................................................................... 23
8.0 REFERENCES ................................................................................................................ 24
LIST OF FIGURES
Figure 1 Regional Location Map
Figure 2 Site Map of Mill Area
Preliminary Mill Decommissioning Plan
Denison Mines Corp. MWH Americas, Inc.
1 September 2011
1.0 SPECIAL PROVISIONS
1.1 Scope of Document
This document outlines the preliminary plans for decommissioning the Denison Mines (USA)
Corp. (Denison) White Mesa Uranium Mill (the “Mill”) site near Blanding, Utah. These plans are
consistent with the previous decommissioning information provided by Denison in their 2009
Reclamation Plan, Version 4.0 (Denison, 2009b). This plan has been prepared by MWH
Americas, Inc. (MWH) for Denison for review and approval by the Utah Department of
Environmental Quality, Department of Radiation Control (Utah DRC). A final decommissioning
plan will be submitted to the Utah DRC for approval within twelve months prior to
commencement of decommissioning activities.
1.2 Definitions
Sections referred to in this document are specific sections of the Preliminary Mill
Decommissioning Plan, referred to as the Plan. The Drawings referred to in this document are
drawings provided in Attachment A to the 2011 Reclamation Plan (Denison, 2011c) that form a
necessary component of this Plan.
For this Plan, Denison is referred to as the Owner, with overall responsibility for site reclamation
and decommissioning.
The Contractor is defined as the group (or groups) selected by Denison and responsible for
conducting the work tasks outlined in Section 1.4 under the direction of and under contract with
Denison.
The Reclamation Project manager is defined as the person appointed by Denison responsible
for ensuring that preparatory work, demolition, material placement, and reclamation site
activities, are conducted according to this Plan.
The Radiation Safety Officer (RSO) is defined as the person appointed by Denison responsible
for worker safety and personnel monitoring. The RSO will be responsible for personnel safety
training, personnel monitoring, and documentation. These tasks will be conducted in
accordance with the Denison Radiation Protection Manual for Reclamation (Denison, 2011b).
1.3 Decommissioning Goals and Implementation Strategy
The project goals for mill decommissioning are outlined below.
1. Attain an as low as reasonably achievable (ALARA) dose outcome for:
a. workers doing the decommissioning,
b. other on-site personnel, and
c. off-site individuals.
2. Optimize the effectiveness of the mill decommissioning plan.
3. Complete decommissioning as soon as practical.
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Denison Mines Corp. MWH Americas, Inc.
2 September 2011
The implementation strategy to achieve the goals for mill decommissioning is listed below.
1. Utilize commercially available demolition equipment to minimize exposures by: (i)
minimizing time of demolition and (ii) keeping personnel from close proximity to
actual demolition activities.
2. Plan the components and establish a work system for these components.
3. Train the work force.
4. Follow the work plan.
5. Evaluate the work plan through project oversight and quality assurance.
6. Modify and continuously improve the work plan.
1.4 Scope of Work
The work outlined in this Plan consists of execution of the following major tasks associated with
facility decommissioning.
1. Setup of health and safety procedures for safety equipment, personnel protective
equipment, personnel monitoring, and personnel exit screening.
2. Execution of pre-decommissioning activities, such as establishing permanent utility
shutoff, material haulage routes, and equipment screening areas.
3. Demolition of above-ground facilities in the process area.
4. Demolition of below-ground facilities in the process area (foundations, paved areas,
concrete pads, roadways, and underground utilities) and placement of these
materials in the last active tailings cell or Cell 1.
5. Excavation of contaminated subsoils from the process area and placement in the last
active tailings cell or Cell 1.
6. Clean-up of windblown contamination and placement in the last active tailings cell or
Cell 1.
7. Regrading and revegetation.
This Plan describes these elements as well as the requirements prior to demolition and the
procedures to be used for specific areas of the process area. The facilities described in this
Plan are shown in Figures 1 and 2.
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DENISON MINES (USA)
MESA MILL,
NOVEMBER.
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MINES
Denison Mines (USA)Corp
PROJECT
TITLE
WHITE MESAMILL TAILINGS RECLAMATION
REGIONAL LOCATION MAP
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DA~EP2011 FIGURE 1
FILE NAME 1009740 LOC MAP
Preliminary Mill Decommissioning Plan
Denison Mines Corp. MWH Americas, Inc.
4 September 2011
2.0 GENERAL REQUIREMENTS AND PROCEDURES
2.1 General
This section outlines the general requirements and procedures to be used during mill
decommissioning.
2.2 Applicable Regulations and Standards
The work shall conform to applicable Federal, State, and County environmental and safety
regulations. The work shall conform to applicable conditions in the Radioactive Materials
License with the Utah DRC. Safety practices, procedures, and monitoring shall be conducted
as specified by the Mine Safety and Health Administration (MSHA) and the current Denison
health and safety procedures in place.
2.3 Health and Safety Requirements
Work outlined in this Plan shall be conducted under the Denison Radiation Protection Manual
for Reclamation (Denison, 2011b), as directed by the RSO. The RSO (and approved assistants
as needed) shall conduct full-time, on-site training, personnel monitoring, and inspection of
construction activities while the site decommissioning work is in progress. The responsibilities
and duties of the RSO for site reclamation and decommissioning shall be as outlined in the
Denison Radiation Protection Manual for Reclamation (Denison, 2011b).
The Contractor shall suspend construction or demolition operations, or implement necessary
precautions whenever (in the opinion of the Reclamation Project Manager or RSO),
unsatisfactory conditions exist due to rain, snow, wind, cold temperatures, excessive water, or
unacceptable traction or bearing capacity conditions. The Reclamation Project Manager and
RSO each have the authority to stop Contractor work if unsafe conditions or deviations from the
Plan are observed.
Process area demolition work will be conducted in accordance with the Denison Radiation
Protection Manual for Reclamation (Denison, 2011b), as directed by the RSO. Due to the
different work activities and potential hazards involved with process area demolition, more
specific procedures will be utilized for demolition work (documented as special operating
procedures or work permits). These procedures will define personal protective equipment and
personnel monitoring (as necessary), regular safety meetings, and communication.
Records pertinent to decommissioning procedures for protection of health and safety will be
stored on-site at the Safety Office during decommissioning. After decommissioning activities
are complete and prior to the site being turned over to the Department of Energy (DOE),
pertinent records will be stored on-site in a temporary storage facility or at the Denison office in
Denver, Colorado.
2.4 Environmental Requirements
2.4.1 Contractor Activities
The Contractor shall store materials, confine equipment, and maintain construction operations
according to applicable law as, ordinances, or permits for the project site. Fuel, lubricating oils,
and chemicals shall be stored and dispensed in such a manner as to prevent or contain spills
and prevent said liquids from reaching local streams or ground water. If quantities of fuel,
Preliminary Mill Decommissioning Plan
Denison Mines Corp. MWH Americas, Inc.
5 September 2011
lubricating oils or chemicals exceed the threshold quantities specified in the Utah regulations,
the Contractor shall prepare and follow a spill Prevention Control and Countermeasures Plan
(SPCCP) as prescribed in applicable Utah regulations. Denison shall approve said plan. Used
lubricating oils shall be disposed of or recycled at an appropriate facility.
2.4.2 Environmental Monitoring
Existing environmental monitoring programs will continue during the time period in which
reclamation and decommissioning is conducted. The environmental monitoring includes
ambient air, external radiation, soil and vegetation, meteorological, stack emissions, and surface
water monitoring. In general, no changes to the existing programs are expected and
decommissioning activities are not expected to increase exposure potential beyond the current
levels. Monitoring procedures are provided in the Denison Environmental Protection Manual
(Denison, 2011a). All records for environmental monitoring are kept in the Environmental Office
at the Mill site as per the Denison Environmental Protection Manual (Denison, 2011a).
2.5 Medical Emergency Procedures
The following procedures will be used when medical services are required, based on two priority
levels.
2.5.1 Level One Priority
For a minor emergency requiring medical treatment (level one priority), the procedures listed
below will be followed.
1. The specific work crew will suspend activities.
2. A member of the work crew will assist the victim and perform first aid.
3. If available, other crew members will contact Denison personnel or the Denison
Safety Coordinator and emergency services personnel.
4. Denison radiation safety personnel will perform a contamination survey on victim and
decontaminate as appropriate.
5. After medical services have been provided, Denison radiation safety personnel will
perform a contamination survey on emergency personnel and equipment.
6. Contaminated equipment or clothing will be retained for evaluation and
decontamination.
2.5.2 Level Two Priority
For a major emergency requiring medical treatment (level two priority), the procedures listed
below will be followed.
1. The specific work crew will suspend activities.
2. If injuries are life threatening, emergency services will be performed immediately and
the victim transported to the nearest emergency medical facility.
3. Surveys for decontamination will be performed after medical services have been
provided. The survey will also be performed on emergency personnel and
equipment for alpha contamination.
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Denison Mines Corp. MWH Americas, Inc.
6 September 2011
4. Contaminated equipment or clothing will be retained for evaluation and
decontamination.
5. Follow other steps as listed for Level One as appropriate.
2.6 Water and Contaminant Management
Management of water and site contaminants is outlined below.
2.6.1 Runon/Runoff Control
Procedures for control of runon and runoff of meteoric water and containment of other liquids
are outlined below. In addition to the procedures listed below, runon and runoff controls will also
follow the Stormwater Best Management Practices Plan (Denison, 2008).
1. Water usage for outdoor dust suppression will be controlled to minimize runoff.
2. Runoff generated from decommissioning operations will be contained on concrete or
asphalt pads or in building sumps.
3. Runon diversion berms will be installed up slope of the facility, if and as necessary, to
minimize storm runon into the decommissioning work area.
4. Runoff retention berms will be installed down slope of the facility, if and as necessary,
to minimize runoff of decontamination liquids and sediment. The liquids contained
will be pumped to a collection sump for removal and be transferred to appropriate
receiving ponds.
5. The control berms will be inspected periodically, and modified or extended during
decommissioning operations, as needed.
6. In addition to berms, the existing runoff control devices and others, such as silt
fences, may be utilized, if and as necessary.
7. The Contractor shall construct and maintain all temporary diversion and protective
works required to divert stormwater from around work areas. The Contractor shall
furnish, install, maintain, and operate all equipment required to keep excavations and
other work areas free from water in order to construct the facilities as specified.
8. Water required by the Contractor for dust suppression or soil moisture conditioning
shall be obtained from wells or surface water storage areas identified by Denison.
2.6.2 Residue Management
Procedures for control of residues are outlined below.
1. Water usage for dust suppression and decontamination washing will be required
during decommissioning operations. Water required by the Contractor for dust
suppression or soil moisture conditioning shall be obtained from wells or surface
water storage areas identified by Denison.
2. Liquids identified during these activities will be contained in the building sumps, area
tanks or on concrete or asphalt pads.
3. The liquid, sediment, and solids collected will either be reused or transported to the
last active tailings cell or Cell 1, or treated for permitted discharge.
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7 September 2011
2.6.3 Contamination Control
Every effort will be made to prevent or minimize the spread of contamination during the
decommissioning operations. Procedures for control of contaminants are outlined below.
1. Personnel, vehicles, and testing equipment shall be surveyed for contamination prior
to leaving the restricted area of the facility.
2. All workers involved in decommissioning operations shall be surveyed for
contamination at the exit screening station and will shower if necessary prior to
leaving the facility. As far as practical, the specific limits will be stated in each
section of this Plan, as determined during the area evaluation.
3. Work area access will be restricted to only authorized personnel during demolition
operations. Access will be restricted during active operations and at the disposal
cell. Signs and /or barrier tape will be used to post areas where access is restricted.
2.6.4 Dust Control
Dust generation will be minimized during all preparation, salvage and demolition activities.
Procedures for control of dust are outlined below.
1. During demolition and removal operations, the equipment and structure surfaces will
be sprayed with water to prevent dust generation.
2. A chemical fixant may be applied to surfaces prone to dust generation.
3. The use of HEPA vacuuming equipment may be utilized.
4. Equipment shall be used in an efficient manner to avoid dust generation.
5. Haul roads, loading, off-loading, material evaluation and disposal areas will be
sprayed with water periodically to control dust generation.
6. Water required by the Contractor for dust suppression or soil moisture conditioning
shall be obtained from wells or surface water storage areas identified by Denison.
2.6.5 Historical and Archaeological Considerations
The Contractor shall immediately notify Denison if materials are discovered or uncovered that
are of potential historical or archeological significance. Denison may stop work in a specific
area until the materials can be evaluated for historical, cultural, or archeological significance. All
materials determined to be of significances shall be protected as determined by appropriate
regulatory agencies, including removal or adjustment of work areas.
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Denison Mines Corp. MWH Americas, Inc.
9 September 2011
3.0 SITE REQUIREMENTS AND PROCEDURES
3.1 General
This section outlines the site-specific requirements and procedures to be used during
decommissioning.
3.2 Site Location
The Denison Mill site is located six miles south of Blanding, Utah on U.S. Highway 191 on a
parcel of land encompassing all or part of Sections 21, 22, 27, 28, 29, 32, and 33 of T37S,
R22E, and Sections 4, 5, 6, 8, 9, and 16 of T38S, R22E, Salt Lake Base and Meridian. The
location description is provided in more detail in Section 3.1 of the Reclamation Plan (Denison,
2011c). The site encompasses approximately 5,415 acres. The Denison facilities are primarily
located within the approximately 686-acre restricted area.
3.3 Climate and Soil Conditions
The climate in the vicinity of the Mill can be considered as semi-arid. Average annual
precipitation is 13.32 inches. Average annual evaporation is approximately 68 inches for Class
A Pan data (Denison, 2009b).
The Mill is located within the Blanding Basin of the Colorado Plateau physiographic province.
The site is underlain by unconsolidated alluvium and indurated sedimentary rocks consisting
primarily of sandstone and shale. The alluvial materials consist mostly of aeolian silts and fin-
grained aeolian sands with thicknesses ranging from a few feet up to 30 feet. The alluvium is
underlain by Mancos Shale (thickness of less than 5 feet), Dakota Sandstone (thickness of
approximately 60 feet) and the Burro Canyon Formation (sandstone with thickness of
approximately 100 feet).
3.4 Site Layout and Facilities
A general layout of the Mill area is shown in Figure 2.
3.4.1 Operation History
The Mill was developed in the 1970s by Energy Fuels Nuclear, Inc. (EFN) and started
operations on May 6, 1980. The Mill processed conventional ores for approximately two and
one-half years before ceasing operations in February 1983. Union Carbide Corporation’s (UCC)
Metals Division obtained a majority ownership interest in 1984. UCC’s Metals Division later
became Umetco Minerals Corporation (Umetco), a wholly owned subsidiary of UCC. Umetco
became the Mill operator starting in 1984. The Mill did not operate in 1984. The Mill processed
conventional ores for part of each year from October 1985 through December 1987 and from
July 1988 through November 1990. Mill operations ceased again from 1991 through 1994.
EFN reacquired sole ownership on May 26, 1994 and processed conventional ores from August
1995 through January 1996. EFN processed alternate feed material (calcium fluoride) from May
1996 through September 1996. Denison (then named International Uranium (USA)
Corporation) and its affiliates acquired the Mill in May 1997 and processed alternate feed from
various sources from 1997 through early 1999, and processed conventional ore from the middle
of 1999 through early 2000. Denison processed alternate feed materials from government
cleanup projects in 2002 and 2003, and processed other alternate feed materials in 2007.
Denison processed uranium and vanadium ores from April 2008 through May 2009. Mill
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Denison Mines Corp. MWH Americas, Inc.
10 September 2011
operations for conventional ore processing were suspended in May 2009 and resumed in March
2010. Conventional ore processing was again suspended in July 2011. Alternate feed
materials were still processed during this time period.
From the early 1990s through 2009, the Mill processed alternate feed materials when the Mill
was not processing conventional ores. An alternate feed circuit was added to the Mill in June
2009 to allow for processing alternate feed materials at the same time as conventional ores.
3.4.2 Access and Security
The access and security at the Mill site during decommissioning will follow the existing Security
Program (Denison, 2007). Access control will be maintained at the Restricted Area boundary
to ensure employees and equipment are released from the site in accordance with the current
License conditions. The Restricted Area is enclosed by a combination of barbed wire and chain
link fencing. The access gates are padlocked and controlled by Denison personnel. Denison
personnel are on-site 24-hours a day, regardless if the mill is in operation. Contractors must
have required training before entering the restricted area.
3.4.3 Utilities
Utilities on site will be maintained by Denison outside of work areas (areas to be
decommissioned or reclaimed). Utilities inside work areas will be provided and maintained by
the Contractor.
3.4.4 Sanitation Facilities
Sanitation facilities will be provided and maintained by the Contractor inside work areas.
3.4.5 Fire Protection
Fire protection will be provided by fire water supply facilities on-site, which include: 1) a 400,000
gallon Storage Tank, of which 250,000 gallons are reserved for fire emergencies; and 2) a
centrifugal diesel driven pump rated at 2,000 gpm at 100 psi. This pump starts automatically
when the pressure in the fire main drops below 100 psi. These fire protection facilities will
decommissioned at the end of the decommissioning schedule. In addition, a fire watchman and
fire extinguisher will be required during demolition-related cutting with a torch or welding
operations.
3.5 Personal Protection Requirements
The protection requirements and procedures to be followed have been developed to assure that
occupational exposures are maintained within the regulatory requirements and As Low as
Reasonably Achievable (ALARA).
1. The standard personnel protection equipment includes full-face respiratory unit
(includes eye protection), hard hat, coveralls, rubber boots or shoe covers, and work
gloves.
2. Alternative personnel protection requirements (either more or less) may be specified
by the area evaluation. If such is the case, each worker will receive a checklist
identifying the specific personnel protection equipment required.
3. Long sleeved coveralls and work gloves will be laundered onsite. New clothing and
gloves will be issued to replace damaged and non-repairable items.
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11 September 2011
4. In accordance with the existing tobacco policy at the mill facility, tobacco use is not
allowed. Eating or drinking anything, including chewing gum, is only allowed in
designated areas.
3.6 Occupational Monitoring Requirements
Programs currently in place for monitoring of exposures to employees will remain in effect
throughout the time period during which mill decommissioning and clean up of windblown
contamination are conducted. This will include personal monitoring and the ongoing bioassay
program. In general, no changes to the existing programs are expected and reclamation and
decommissioning activities are not expected to increase exposure potential beyond the current
levels. The current requirements to monitor potential personnel exposure to radionuclides are
specified in the Denison Radiation Protection Manual for Reclamation (Denison, 2011b).
3.7 Operational Issues
The Plan presumes that virtually all structures on the site can be demolished using heavy
equipment as described below. As a result, little or no manual labor is anticipated. This
approach should accelerate the demolition process, as well as reduce occupational exposures.
The following describes the typical work routine to be followed during demolition.
1. The demolition crew supervisor shall review the Plan requirements and confer with
the Reclamation Project Manager for changes made to the Plan. The crew
supervisor will inform the work crew of the requirements and any changes to the
Plan. The RSO will assist when requested.
2. A staging area will be established near the work area and used as a personnel
screening, PPE changing and storage area.
3. Personnel involved in the demolition will don the required PPE and required
monitoring equipment.
4. Demolition personnel will be surveyed for contamination, decontaminated if over the
specific limits and resurveyed prior to leaving the Restricted Area.
5. All personnel performing demolition work shall be scanned for contamination and
may shower before release from the Restricted Area.
6. PPE equipment will be inspected, decontaminated, and maintained in good working
order and replaced when damaged.
7. Personnel involved in demolition operations must report problems encountered or
changes that need to be made to the Plan to the Reclamation Project Manager.
Problems encountered and changes made will be documented in daily progress
reports.
3.8 Training
Formal worker training will be required for all decommissioning activities and will be appropriate
for the activity to be performed. The training will be given by the RSO or designee, and will
include the following information.
1. Goals, strategies and specific tasks encompassed by this Plan.
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12 September 2011
2. Radiation protection training will be conducted for all contractor employees as
specified in the Denison Radiation Safety Training Program (Denison, 2009a). The
general training will include radiological safety procedures, ALARA philosophy and
emergency procedures. The personnel will receive instruction pertaining to the risks
of radiation exposure, monitoring procedures and personal protective equipment.
3. MSHA training will be required for all contractor employees. This training will be site
and job specific, and will include information on industrial safety, building safety,
chemical hazards, fire safety, emergency procedures, protective equipment, and an
overview of planned activities.
4. Training will be documented as required by MSHA, and the appropriate procedures
in the Denison Radiation Safety Training Program (Denison, 2009a).
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13 September 2011
4.0 EQUIPMENT SALVAGE
4.1 General
Equipment and structural materials (if of sufficient value for salvage) may be removed from the
facility, decontaminated and surveyed for release from the site for unrestricted use. All
salvageable equipment will be decontaminated as outlined below and surveyed for release in
accordance with the terms of License Condition 9.10. Equipment and structural materials that
are not of sufficient value or salvage or cannot be feasibly decontaminated will be placed in the
in the last active tailings cell or Cell 1.
4.2 Decontamination
Decontamination of potentially salvageable equipment will be conducted based on the nature of
contamination, the surfaces to be decontaminated, and worker health and safety.
Decontamination methods will include low-pressure washing, followed by surveying of washed
surfaces. If contamination remains, decontamination methods will include scraping, steam
cleaning, sand blasting, or grinding. Surveying of cleaned surfaces will be conducted on dried
surfaces, with release based on criteria specified in the Denison Radiation Protection Manual for
Reclamation (Denison, 2011b). Equipment and structural materials shall not be release from
the site without approval by the RSO.
4.3 Decontamination Procedures
Efforts will be made to minimize the spread of contamination on salvageable equipment.
Decontamination liquids or chemicals may be used to aid in equipment contamination removal.
General procedures for decontamination are listed below.
1. Wet down areas and equipment surfaces with water spray followed by water
washing. Steam cleaning may be required to augment washing.
2. Wash equipment and structures and remove loose residue.
3. Wash insides of equipment and dispose of residues.
4. Collect liquids generated during decontamination activities for disposal.
Material and equipment slated for disposal will be transported to the last active tailings cell or
Cell 1. Salvageable items meeting unrestricted release criteria will be transported to a
designated clean area for storage. Salvageable items meeting restricted release criteria will be
transported to a designated restricted release are for storage.
4.4 Decontamination Areas
A decontamination area will be established so that equipment to be offered for salvage may be
decontaminated, as necessary. This area is planned to be an existing concrete pad with a water
collection area or sump.
A laydown area will be established outside of the facility Restricted Area so that
decontaminated, salvageable equipment that has been surveyed and approved for unrestricted
release can be stored prior to release from Denison custody. A separate laydown area will be
established within the restricted area for equipment decontaminated for restricted release, if any.
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14 September 2011
5.0 PRE-DEMOLITION ACTIVITIES
5.1 General
This section describes the preparation of the site areas for reclamation and decommissioning.
This work will be conducted according to applicable sections of the Denison Radiation
Protection Manual for Reclamation (Denison, 2011b). The Contractor shall conduct these
activities using written procedures that have been approved by Denison.
5.2 Area Evaluation Process
For each structure in the process area, a pre-demolition survey and inventory will be conducted.
This work (area evaluation process) will include the items listed below.
1. Review health protection requirements (if different from the standard).
2. Review monitoring requirements (if different from the standard).
3. Review utilities to confirm that electrical power lines, high pressure pipelines and
other potential hazards to demolition are identified.
4. Perform radiation surveys to identify areas of above-background exposure to ionizing
radiation. Denison’s historical survey data may be used for this purpose.
5. Sample air to identify the need for respiratory protection from dust, gases, and
airborne radioactivity. This would include radon daughter surveys to identify potential
areas of exposure to radon-222 gas.
6. Survey hazardous materials to identify and quantify potentially hazardous materials
such as strong acids or bases, oxidizing agents, corrosive materials, flammable
materials or pressurized gases.
7. Review asbestos inspection report (see Section 5.3.4) to determine the presence of
asbestos-containing materials and procedures for handling and disposal.
8. Survey residual liquid to identify residual liquids in tanks, vessels, pipelines, and
other storage areas that would require liquid management for treatment and
disposal.
9. Conduct structural engineering surveys to assess the physical condition of the
structure and its supporting members.
10. Identify equipment that will be reused, salvaged, or disposed.
11. Determine what structural members or equipment needs to be cut into manageable
sections for transport.
12. Decide if supplemental runoff control berms need to be constructed or modified.
13. Obtain area and equipment contamination measurements.
14. Mark salvageable equipment, if necessary.
15. Plan haulage routes.
Preliminary Mill Decommissioning Plan
Denison Mines Corp. MWH Americas, Inc.
15 September 2011
5.3 General Preparation Work
5.3.1 Circuit Cleanup
Circuits will be flushed and resultant fluids and solids will be pumped to the appropriate
receiving pond. All products will be removed from product storage buildings, prior to demolition
of those buildings. Reagents used in the processing will be removed from the site or disposed
of as described below.
Process inorganic compounds. Acids, bases or other inorganics that have become
contaminated with radioactive materials will be pH-adjusted or otherwise neutralized, if and as
necessary, and will be disposed of in the last active tailings cell or Cell 1. Inorganics that are
unaffected by the process (because they were unused) will be sold or returned to the original
vendor, if possible. Otherwise, the pH will be adjusted or otherwise neutralized, if and as
necessary, and disposed of in the last active tailings cell or Cell 1.
Process organic compounds. Organics used in processing will be stripped with sulfuric acid
or other reagents to remove radionuclides and metals and disposed as appropriate.
Uncontaminated organics will be returned to the original vendor or sold, if possible.
5.3.2 Laboratory Reagents
Laboratory reagents will be returned to the original vendor, sold, donated to appropriate users or
neutralized and placed in the appropriate disposal location.
5.3.3 Oils and Lubricants
New oils will be returned to the original vendor, sold to another party, or disposed as necessary.
Used oils will be disposed locally, if not contaminated. If contaminated, the used oils will be
disposed of at a mixed waste disposal facility.
5.3.4 Asbestos
An initial site survey to determine the amount of sampling and characterization required for a
facility-wide asbestos inspection is scheduled to be completed by September 30, 2011. The
facility-wide inspection to determine the presence of asbestos in building materials in the milling
facility will be conducted for Denison in the spring of 2012. The investigation will identify
buildings and facilities where no suspect materials are identified, or sampled materials did not
test positive for asbestos-containing materials. A detailed asbestos survey will be conducted, if
and as necessary, on a building-by-building basis to confirm identification of building materials
and outline methods of asbestos containment, handling, and disposal. An inspection report will
be prepared after the facility-wide inspection. The report will be submitted to the DRC as a
standalone document. Asbestos-containing materials will be removed according to pertinent
asbestos regulations and procedures presented in the inspection report and will be placed in the
last active tailings cell or Cell 1.
5.4 Process Area Preparation
Work in the process area includes the water management tasks outlined below.
1. Removal and/or evaporation of water in existing ponds.
2. Diversion of clean area stormwater runoff from work areas (where facilities
demolition and material excavation will take place).
Preliminary Mill Decommissioning Plan
Denison Mines Corp. MWH Americas, Inc.
16 September 2011
3. Collection of stormwater runoff from within the work areas to be used for disposed
material compaction or dust suppression and/or retained in a temporary evaporation
pond.
5.5 Staging and Storage Areas
Areas on site used for equipment or material staging or temporary storage will be in approved
areas of the site. These areas will be prepared in a manner consistent with Denison plans for
stormwater management. These areas will be prepared in conjunction with facilities demolition
and site reclamation work.
Preliminary Mill Decommissioning Plan
Denison Mines Corp. MWH Americas, Inc.
17 September 2011
6.0 PROCESS AREA DEMOLITION
6.1 General Description
This section outlines the demolition of facilities and structures in the process area. The major
structures are shown on Figure 2 and are outlined in this section.
6.2 Mill Area
The uranium and vanadium processing areas of the Mill, including all equipment, structures and
support facilities, will be decommissioned and disposed of in tailings or buried on site as
appropriate. All equipment, including tankage and piping, agitation equipment, process control
instrumentation and switchgear, and contaminated structures will be cut up, removed and buried
in tailings prior to final cover placement. Concrete structures and foundations will be broken up
and removed. Concrete foundations may be left in place and covered with soil as appropriate.
These decommissioned areas would include, but not be limited to the following:
Coarse ore bin and associated equipment, conveyors and structures.
Grind circuit including semi-autogeneous grind (SAG) Mill, screens, pumps and
cyclones.
The three pulp storage tanks to the east of the Mill building, including all tankage,
agitation equipment, pumps and piping.
The seven leach tanks inside the main Mill building, including all agitation equipment,
pumps and piping.
The counter-current decantation (CCD) circuit including all thickeners and
equipment, pumps and piping.
Uranium precipitation circuit, including all thickeners, pumps and piping.
The two yellow cake dryers and all mechanical and electrical support equipment,
including uranium packaging equipment.
The clarifiers to the west of the Mill building including the preleach thickener (PLT),
clarifier and claricone.
The boiler and all ancillary equipment and buildings.
The entire vanadium precipitation, drying and fusion circuit.
All external tankage not included in the previous list including reagent tanks for the
storage of acid, ammonia, kerosene, water, dry chemicals, etc. and the vanadium
oxidation circuit.
The uranium and vanadium solvent extraction (SX) circuit including all SX and
reagent tankage, mixers and settlers, pumps and piping.
The SX building.
The Mill building.
The Alternate Feed processing circuit
Decontamination pads
Preliminary Mill Decommissioning Plan
Denison Mines Corp. MWH Americas, Inc.
18 September 2011
The office building.
The shop and warehouse building.
The sample plant building.
The Reagent storage building.
6.3 Demolition Strategy
As described above, a number of pre-demolition activities will be completed prior to actual
demolition of the structures and buildings. This approach assumes that the facility equipment,
buildings, and structures will have any product, reagents, residues and other fluids removed.
Utilities for individual buildings will be disconnected on a building-by-building basis.
6.3.1 Staging of Decommissioning
Although different types of decommissioning equipment will be used to demolish each different
type of structure or equipment, demolition will proceed according to the general staging process
described below while allowing for maximum use of the support areas of the facility such as the
office and shop areas. The first stage consists of demolition of above-ground structures such as
piping and tanks, then building and enclosed structures. The second stage consists of concrete
removal (structure floor slabs, below-ground walls, and footings). The third stage consists of
removal of underground utilities (most likely conducted at the same time as concrete removal).
The fourth stage is excavation and removal of contaminated soils.
6.3.2 Remote Demolition
The strategy for demolition is based on current equipment and procedures used for structural
demolition and used successfully at uranium mill sites in the western United States. This
strategy consists of use of mechanized equipment specially designed for equipped for
demolition work, minimizing manual labor. Heavier duty equipment will allow remote-controlled
water sprays to be directed as necessary, will require fewer staff, and will lower occupational
exposures.
6.3.3 Demolition Equipment
The anticipated demolition equipment is described below. All heavy equipment to be used for
demolition should have an enclosed operator’s cabin that is equipped with a HEPA filter and an
air conditioning system. This enclosure will reduce potential internal exposures from airborne
materials.
Hydraulic shear. This is a hydraulically operated attachment on the end of the arm of a track-
mounted excavator or crane. This shear will be used to cut piping, I-beams, tanks and other
steel into pieces that will fit onto trucks for transport to the last active tailings cell or Cell 1.
Grapple. This is a hydraulically operated attachment on the end of the arm of the track-
mounted excavator or crane. The grapple is either an excavator bucket with a thumb, or a
grasping attachment with several “fingers.” The grapple will be used to load dismantled pieces
of piping, tanks, and concrete onto trucks for transport to the last active tailings cell or Cell 1.
Hydraulic excavator. A large hydraulic excavator will be used to load dismantled pieces of
piping, tanks, and concrete onto trucks for transport to the last active tailings cell or Cell 1. Also,
Preliminary Mill Decommissioning Plan
Denison Mines Corp. MWH Americas, Inc.
19 September 2011
excavator buckets with different widths may be used to excavate solids from tanks or cemented
soils from around deeper foundations or pilings.
Front-end loader. In areas with smooth ground conditions and free from debris that may
damage rubber tires, a front-end loader will be used to load soil, dismantled pieces of piping,
tanks, or concrete onto trucks for transport to the last active tailings cell or Cell 1.
Concrete shear. This is a hydraulically operated attachment on the end of the arm of a track-
mounted excavator or crane. The concrete shear is similar to the steel shear, used to break
concrete walls, slabs, and other facilities that will fit into the jaws of the shear. The shear breaks
the concrete into pieces that can be loaded for transport to the last active tailings cell or Cell 1.
Concrete impactor. For concrete foundations that are of dimensions that cannot be broken
with the concrete shear, a concrete impactor will be used. This is another attachment on the
end of the arm of a track-mounted excavator or crane. The impactor use a vibratory tip (similar
to a jack-hammer) to break concrete into pieces that can be loaded into trucks for transport to
the last active tailings cell or Cell 1.
Trucks. Dump trucks as large as are practical and available will be used to transport
dismantled equipment, concrete, and soils to the last active tailings cell or Cell 1 with minimal
handling. The size of the truck beds will dictate the size of the facility debris to be broken or cut.
Scraper. For soils excavated during the later phase of contaminated soil excavation, scrapers
may be used in place of trucks and loaders. Push-loading scrapers would most likely be used
for soil excavation, transport, and placement.
Soil ripper. To expedite contaminated soil excavation, a dozer or grader-mounted soil ripper or
ripping bar will be used to break up cemented soil or sedimentary rock to enable scrapers or
loaders to load contaminated soils.
Water truck. A water truck or similar rubber-tired watering equipment will be routinely used for
dust suppression to wet haul roads from the specific demolition site to the area of the last active
tailings cell and Cell 1.
Grader. A road grader or blade will be used to smooth haul roads and other work surfaces on a
routine basis. Debris, rock, or wet materials generated by the blade work will be transported to
the last active tailings cell or Cell 1.
6.4 Utilities Management
All utilities to the facility will be disconnected prior to starting demolition operations for a given
building, structure or area. The specific procedures and precautionary measures for each utility
to be followed are listed below.
6.4.1 Liquefied Natural Gas and Propane Systems Disconnect
1. Shut off main valve at meter.
2. Light heating equipment to burn off residual fuel.
3. Blow out all lines with compressed air.
4. Verify with combustible gas meter that lines are free of fuel.
Preliminary Mill Decommissioning Plan
Denison Mines Corp. MWH Americas, Inc.
20 September 2011
6.4.2 Electrical System Disconnect
1. Shut down service at electrical substations.
2. Verify with metering equipment that the power is off.
3. Disconnect power feeders to the milling facility.
4. Verify with metering equipment that all systems are disconnected.
6.4.3 Water System Disconnect
1. Disconnect the piping system to the milling facility (if not already disconnected).
2. Check main valve to verify system is off and disconnected.
6.4.4 Phone System
Denison will also have telephone services maintained in the office build for use during
decommissioning and eventually disconnected by the provider.
6.5 Surface Structure Removal
As described in the strategy above, the order in which structures will be demolished and
removed is generally determined by the types of tools that are best suited to those types of
structures. Therefore, all surface structures will be demolished prior to concrete and
contaminated soil removal. All materials will be disposed in last active tailings cell or Cell 1.
Depending on the type of building, it may be demolished with equipment and structures
remaining inside or the equipment may be removed prior to the building’s structure being
demolished. Buildings and their associated equipment will be the first major category of
demolition that is performed, except for support areas of the facilities such as the office and
shop areas. It is anticipated that the type of demolition equipment used to take down buildings
will be the same required for outdoor piping and tanks.
6.6 Concrete Removal
Once surface structures, including all buildings, tanks, piping, and pipe racks, have been
demolished and disposed, then specialized concrete removal operations may begin.
It is anticipated that the major equipment used will be a concrete shear, a concrete impactor, a
large backhoe, and haulage trucks. Each of these will be operated from within an enclosed cab,
thus reducing exposure to radioactive materials. Concrete floors and walls of normal size and
thickness (up to 1 foot) will be removed using the heavy equipment described above. Concrete
shears will be used to cut slabs into pieces that are transportable to the disposal cell.
Concrete below grade and thicker than 1 foot will likely be broken using a combination of the
impactor, the shear, and a backhoe that will dig access trenches. Removal of structure
foundations, interior floor slabs, and exterior slabs and parking areas will follow the general
sequence listed below.
1. Cutting (with a concrete saw) or breaking up (with a hydraulic shear, remote jack
hammer or similar vibratory tool) the slab or foundation material into pieces that can
be loaded and hauled by construction equipment.
Preliminary Mill Decommissioning Plan
Denison Mines Corp. MWH Americas, Inc.
21 September 2011
2. Excavation of contaminated soils from under floor areas and around footings.
3. Transport of the concrete pieces and excavated soils to last active tailings cell, Cell 1
or approved temporary storage location.
4. Placement of the pieces in the disposal cell by dumping and (where possible)
working with a dozer or trackhoe to minimize void spaces.
5. Covering the pieces with contaminated soil or similar material, with vibratory
compaction to minimize void spaces.
6.7 Utility Removal
Equipment to be used to utilities (both above-ground and below-ground) depend on the location
of the structure. It is anticipated that the major equipment used will be a hydraulic shear, a
grapple, a large backhoe, and haulage trucks. Each of these will be operated from within an
enclosed cab, thus reducing exposure to radioactive materials.
Once the concrete structures are removed, the underground utilities will be located and exposed
with a metal detector or conductivity meter in conjunction with existing utility maps will be used
to locate pipes and lines. A combination of the backhoe and the grapple will be used to expose
the lines, which will be severed using the hydraulic shear.
6.8 Miscellaneous Site-Wide Facilities
An outside contractor will be retained to empty the septic tanks prior to demolition. The septic
tanks and the drain fields will be excavated and transported to last active tailings cell or Cell 1.
Sewer system piping will be excavated and disposed of after flushing.
Miscellaneous facilities to be decommissioned include the boneyard, tailings lines, and mill
runoff controls. The boneyard is located to the south of the Mill area and consists of a collection
of used and potentially contaminated equipment and equipment parts that have been removed
from the Mill or various other buildings over a period of time. The surface tailings lines will be
removed one all liquid effluent from the demolition is completed and not more liquid effluent is
expected. Mill runoff control systems including underground culverts and miscellaneous
concrete structures will be decommissioned.
6.9 Contaminated Soils
Contaminated areas on the Mill site will be primarily superficial and include the ore storage area
and surface contamination of some roads. All ore and alternate feed materials will have been
previously removed from the ore stockpile area or will be transported and disposed of as
contaminated material. The depth of excavation will vary depending on the extent of
contamination and will be governed by the criteria outlined in Attachment A (Plans and
Specifications) of the Reclamation Plan (Denison, 2011c).
Contaminated soils will be disposed of in last active tailings cell or Cell 1. Contaminated soils
will be placed in the last active cell or Cell 1 as random fill material (material used to fill voids
within mill material, achieve desired cover system slopes, and provide a firm base for
construction of the cover system). Only uncontaminated soils meeting criteria for cover
materials will be used in the cover system over the tailings cells.
Preliminary Mill Decommissioning Plan
Denison Mines Corp. MWH Americas, Inc.
22 September 2011
6.10 Windblown Contamination
Windblown contamination is defined as Mill derived contaminants dispersed by the wind to
surrounding areas. The potential areas affected by windblown contamination will be surveyed
using scintillometers taking into account historical operational data from the Semi-annual
Effluent Reports and other guidance such as prevailing wind direction and historical background
data. Areas covered by the existing Mill facilities and ore storage pad, the tailings cells and
adjacent stockpiles of random fill, clay and topsoil, will be excluded from the survey. Materials
from these areas will be removed in conjunction with final reclamation and decommissioning of
the Mill and tailings cells. Windblown contaminated material will be detected by a gamma survey
using the criteria in Attachment A (Plans and Specifications) of the Reclamation Plan (Denison,
2011c) and will be excavated and disposed of in the last active tailings cell or Cell 1.
6.11 Preparation of Demolition Debris for Disposal
Because of the wide variety in shape and size of equipment and structural materials, the
following guidelines will be used in sizing, handling and disposing of debris. Additional detail on
material placement is provided in Attachment A (Plans and Specifications) of the Reclamation
Plan (Denison, 2011c).
1. Material will be cut or dismantled into pieces that can be safely lifted or carried with
the equipment being used. Material will also be cut or dismantled to minimize void
spaces after disposal.
2. A front-end loader, crawler, hydraulic excavator, or equivalent equipment will be
utilized to crush or compact compressible materials. These materials will be laid out
in a staging area or other approved area to facilitate crushing or compacting with
equipment.
3. Pipe or conduit with an opening or diameter large than 12 inches that cannot be
crushed will be filled with random fill prior to disposal.
4. Tanks and vats will be handled according to the wall material and wall thickness.
Tanks will be crushed or compacted if possible. Tanks that cannot be crushed will be
dismantled, if feasible. Tanks that cannot be crushed or dismantled will be
transported to the last active tailings cell or Cell 1, filled with random fill and buried.
Preliminary Mill Decommissioning Plan
Denison Mines Corp. MWH Americas, Inc.
23 September 2011
7.0 REGRADING AND REVEGETATION
7.1 Regrading
Regrading will be conducted after completion of contaminated soil excavation. The excavated
surface of the mill facility will be regraded to remove depressions and direct storm water runoff
in directions and toward areas desired for final site drainage. The completed regraded surfaces
will be covered with a layer of topsoil or suitable plant growth media soil at a minimum thickness
of six inches.
7.2 Revegetation
Revegetation will consist of establishing a self-sustaining cover of selected vegetation of the
completed regraded and covered surfaces of the milling facility. The vegetation species mix,
planting methods, weed control procedures, and revegetation success monitoring will be
selected and approved prior to start of revegetation work.
Preliminary Mill Decommissioning Plan
Denison Mines Corp. MWH Americas, Inc.
24 September 2011
8.0 REFERENCES
Denison Mines (USA) Corp. (Denison), 2007. White Mesa Mill Security Program, Book #16,
Revision R-1. February 25.
Denison Mines USA Corp. (Denison), 2008. Stormwater Best Management Practices Plan,
White Mesa Mill, Blanding Utah, Revision 1.3, June 12.
Denison Mines (USA) Corp. (Denison), 2009a. White Mesa Mill – Standard Operating
Procedures, Book #13, Training, Addendum 9 – Radiation Safety Training Program. August
Denison Mines (USA) Corp. (Denison), 2009b. Reclamation Plan White Mesa Mill, Blanding,
Utah, Version 4.0. November.
Denison Mines (USA) Corp. (Denison), 2011a. White Mesa Mill – Standard Operating
Procedures, Book #11, Environmental Protection Manual. January.
Denison Mines (USA) Corp. (Denison), 2011b. White Mesa Mill, Standard Operating
Procedures, Book #20, Radiation Protection Manual for Reclamation. September.
Denison Mines (USA) Corp. (Denison), 2011c. Reclamation Plan White Mesa Mill, Blanding,
Utah, Version 5.0. September.