HomeMy WebLinkAboutDRC-2011-007451_5 - 0901a0688027e863ATTACHMENT A
PLANS AND TECHNICAL SPECIFICATIONS FOR
RECLAMATION OF WHITE MESA MILL FACILITY
BLANDING, UTAH
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White Mesa Mill Reclamation Plan
TABLE OF CONTENTS
1 SPECIAL PROVISIONS .............................................................................................. A-1
1.1 Scope of Document ...................................................................................................... A-1
1.2 Definitions and Roles ................................................................................................... A-1
1.3 Scope of Work .............................................................................................................. A-3
1.4 Applicable Regulations and Standards ......................................................................... A-4
1.5 Permits .......................................................................................................................... A-5
1.6 Inspection and Quality Assurance ................................................................................ A-5
1.7 Construction Documentation ........................................................................................ A-6
1.8 Design Modifications ................................................................................................... A-7
1.9 Environmental Requirements ....................................................................................... A-7
1.10 Water Management ...................................................................................................... A-8
1.11 Historical and Archeological Considerations ............................................................... A-8
1.12 Health and Safety Requirements .................................................................................. A-8
1.13 Personnel Monitoring ................................................................................................... A-9
1.14 Environmental Monitoring ........................................................................................... A-9
2 SITE CONDITIONS .................................................................................................... A-10
2.1 Site Location .............................................................................................................. A-10
2.2 Climate and Geology .................................................................................................. A-10
2.3 Past Operations ........................................................................................................... A-10
2.4 Facilities Demolition .................................................................................................. A-11
2.5 Disposed Materials ..................................................................................................... A-11
2.6 Construction Materials ............................................................................................... A-11
2.6.1 Liner Materials .................................................................................................... A-12
2.6.2 Random Fill ........................................................................................................ A-12
2.6.3 Topsoil ................................................................................................................ A-12
2.6.4 Rock Mulch ......................................................................................................... A-12
2.6.5 Erosion Protection and Perimeter Apron Material.............................................. A-12
2.6.6 Filter Materials .................................................................................................... A-12
2.6.7 Granular Materials .............................................................................................. A-13
2.7 Staging and Stockpile Areas ...................................................................................... A-13
2.8 Access and Security ................................................................................................... A-13
2.9 Utilities ....................................................................................................................... A-13
2.10 Sanitation Facilities .................................................................................................... A-13
3 WORK AREA PREPARATION ................................................................................ A-14
3.1 General ....................................................................................................................... A-14
3.2 Water Management .................................................................................................... A-14
3.3 Cell Construction........................................................................................................ A-15
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3.4 Soil Borrow Areas ...................................................................................................... A-15
3.5 Clearing and Stripping ............................................................................................... A-15
3.5.1 Clearing ............................................................................................................... A-15
3.5.2 Stripping .............................................................................................................. A-16
4 CELL 1 DISPOSAL AREA BASE CONSTRUCTION ........................................... A-17
4.1 General ....................................................................................................................... A-17
4.2 Materials Description ................................................................................................. A-17
4.2.1 Subgrade Fill ....................................................................................................... A-17
4.2.2 Clay Liner Material ............................................................................................. A-17
4.3 Work Description ....................................................................................................... A-18
4.3.1 Foundation Preparation ....................................................................................... A-18
4.3.2 Disposal Cell Foundation Area ........................................................................... A-18
4.3.3 Subgrade Fill Placement ..................................................................................... A-18
4.3.4 Clay Liner Material Placement ........................................................................... A-18
4.4 Performance Standards and Testing ........................................................................... A-19
4.4.1 Subgrade Testing ................................................................................................ A-20
4.4.2 Clay Liner Testing .............................................................................................. A-20
4.4.3 Grading Tolerances ............................................................................................. A-21
5 DISCHARGE CHANNEL GRADING ...................................................................... A-22
5.1 General ....................................................................................................................... A-22
5.2 Work Description ....................................................................................................... A-22
5.2.1 Discharge Channel Excavation ........................................................................... A-22
5.2.2 Grading Tolerances ............................................................................................. A-22
6 MILL DECOMMISSIONING .................................................................................... A-23
6.1 Mill Buildings and Equipment ................................................................................... A-23
6.2 Mill Site ...................................................................................................................... A-25
6.3 Windblown Contamination ........................................................................................ A-25
6.4 Guidance ..................................................................................................................... A-26
6.5 General Methodology ................................................................................................. A-26
6.6 Scoping Survey .......................................................................................................... A-27
6.7 Characterization and Remediation Control Surveys .................................................. A-29
6.8 Final Survey ............................................................................................................... A-29
6.9 Employee Health and Safety ...................................................................................... A-32
6.10 Environment Monitoring ............................................................................................ A-32
6.11 Quality Assurance ...................................................................................................... A-32
7 MATERIAL DISPOSAL ............................................................................................ A-33
7.1 General ....................................................................................................................... A-33
7.2 Materials Description ................................................................................................. A-33
7.2.1 Raffinate Crystals................................................................................................ A-33
7.2.2 Synthetic Liner .................................................................................................... A-33
7.2.3 Contaminated Soils ............................................................................................. A-33
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7.2.4 Mill Debris .......................................................................................................... A-34
7.3 Work Description ....................................................................................................... A-34
7.3.1 Raffinate Crystals................................................................................................ A-34
7.3.2 Synthetic Liner .................................................................................................... A-34
7.3.3 Contaminated Soils ............................................................................................. A-34
7.3.4 Mill Debris .......................................................................................................... A-35
7.3.5 Material Sizing and Preparation .......................................................................... A-35
7.3.6 Incompressible Debris ........................................................................................ A-35
7.3.7 Compressible Debris ........................................................................................... A-36
7.3.8 Organic Debris .................................................................................................... A-36
7.3.9 Soils and Similar Materials ................................................................................. A-37
7.4 Performance Standards and Testing ........................................................................... A-37
7.4.1 Material Compaction – Debris Lifts ................................................................... A-37
7.4.2 Material Compaction - Disposed Materials ........................................................ A-38
7.4.3 Testing Frequency ............................................................................................... A-38
7.4.4 Final Slope and Grades ....................................................................................... A-39
8 COVER CONSTRUCTION ....................................................................................... A-40
8.1 General ....................................................................................................................... A-40
8.2 Materials Description ................................................................................................. A-40
8.2.1 Cover Random Fill .............................................................................................. A-40
8.2.2 Organic Matter Amendment ............................................................................... A-40
8.2.3 Rock Mulch ......................................................................................................... A-41
8.2.4 Erosion Protection and Perimeter Apron Rock ................................................... A-41
8.2.5 Erosion Protection Filter ..................................................................................... A-42
8.2.6 Topsoil ................................................................................................................ A-42
8.3 Work Description ....................................................................................................... A-42
8.3.1 Monitoring Interim Cover Settlement ................................................................. A-43
8.3.2 Monitoring Final Cover Settlement .................................................................... A-44
8.3.3 Monitoring Settlement Points ............................................................................. A-44
8.3.4 Platform Layer Fill .............................................................................................. A-44
8.3.5 Highly Compacted Layer .................................................................................... A-44
8.3.6 Water Storage Layer Fill Placement .................................................................. A-45
8.3.7 Organic Matter Amendment ............................................................................... A-45
8.3.8 Rock Mulch Placement ....................................................................................... A-45
8.3.9 Topsoil Placement ............................................................................................... A-46
8.3.10 Rock and Filter Material Placement ................................................................... A-46
8.4 Performance Standard and Testing ............................................................................ A-47
8.4.1 Platform Fill Testing ........................................................................................... A-47
8.4.2 Highly Compacted Layer Testing ....................................................................... A-48
8.4.3 Water Storage Layer Fill Material Testing ........................................................ A-49
8.4.4 Topsoil Testing ................................................................................................... A-50
8.4.5 Rock Mulch Testing ............................................................................................ A-50
8.4.6 Erosion Protection and Perimeter Apron Rock Testing ...................................... A-52
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8.4.7 Erosion Protection Filter Testing ........................................................................ A-52
8.4.8 Rock Durability Testing ...................................................................................... A-53
8.5 Surface Slopes and Grades ......................................................................................... A-53
8.6 Grading Tolerances .................................................................................................... A-53
9 REVEGETATION ....................................................................................................... A-54
9.1 General ....................................................................................................................... A-54
9.2 Materials Description ................................................................................................. A-54
9.2.1 Soil Amendments ................................................................................................ A-54
9.2.2 Seed Mix ............................................................................................................. A-54
9.2.3 Erosion Control Materials ................................................................................... A-55
9.3 Work Description ....................................................................................................... A-56
9.4 Soil Amendment Application ..................................................................................... A-56
9.5 Growth Zone Preparation ........................................................................................... A-56
9.6 Seed Application ........................................................................................................ A-56
9.7 Erosion Control Material Application ........................................................................ A-57
9.8 Performance Standard and Testing ............................................................................ A-58
9.8.1 Seeding Rates ...................................................................................................... A-58
9.8.2 Erosion Control ................................................................................................... A-58
9.8.3 Weed Control ...................................................................................................... A-58
9.8.4 Vegetation Establishment Performance .............................................................. A-58
10 REFERENCES ............................................................................................................. A-59
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1 SPECIAL PROVISIONS
1.1 Scope of Document
The following technical specifications have been prepared for reclamation and decommissioning
of the Denison Mines (USA) Corp. (Denison), White Mesa Uranium Mill Facility in Blanding,
Utah. These technical specifications have been prepared for review and approval by the Utah
Department of Environment Quality (“DEQ”), Division of Radiation Control (“DRC”) and are
submitted as an attachment to the 2011 Reclamation Plan. The design drawings for reclamation
are included in this attachment and are designated as the “Drawings”. The Construction Quality
Assurance/Quality Control Plan (“CQA/QC Plan”) referenced in this document is provided as
Attachment B to the 2011 Reclamation Plan.
These technical specifications have been written assuming (a) a contractor will conduct tailings
impoundment reclamation under contract with Denison and under Denison’s direction, and (b)
the work quality will be checked with independent (third-party) construction quality assurance.
1.2 Definitions and Roles
Construction Quality Assurance (CQA) – A planned and systematic pattern of means and
actions designed to assure adequate confidence that the materials or services meet contractual
and regulatory requirements and will perform satisfactorily in service. CQA refers to means and
actions employed by the involved parties to assure conformity of the project work with the
CQA/QC Plan, the Drawings, and the Technical Specifications.
Construction Quality Control (CQC) – Actions which provide a means to measure and
regulate the characteristics of an item or service in relation to contractual and regulatory
requirements. CQC refers to those actions taken by the Contractor, technicians, or other
involved parties to verify that the materials and the workmanship meet the requirements of the
CQA/QC Plan, the Drawings, and the Technical Specifications.
Technical Specifications – The document that prescribes the requirements and standards for the
specific elements of the reclamation. The Technical Specifications will be prepared in final form
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prior to commencement of reclamation activities.
Drawings – The detailed project drawings to be used in conjunction with the Technical
Specifications. The Drawings will be prepared in final form as construction drawings prior to
reclamation.
Construction Project – The total authorized/approved reclamation project that requires several
construction segments to complete.
Construction Segment – A portion of the total construction project involving a specific area or
type of work. Several construction segments will likely take place simultaneously during
reclamation.
Construction Task – A basic construction feature of a construction segment involving a specific
construction activity.
ASTM Standards – The latest versions of the American Society for Testing and Materials
specifications, procedures and methods.
For these Technical Specifications, Denison is referred to as the Owner, with overall
responsibility for closure, as well as site reclamation.
The on-site Construction Manager is responsible for the conduct, direction and supervision of
all reclamation activities as detailed in the Drawings and Technical Specifications.
The Design Engineer is responsible for the design of the various elements of the reclamation
project and for preparing the Drawings and Technical Specifications.
The Contractor is defined as the group (or groups) selected by Denison and responsible for
conducting the work tasks outlined in Section 1.3 under the direction of, and under contract with
Denison.
The Surveyor is a party, independent from the Owner or Contractor, who is responsible for
surveying, documenting, and verifying the location of all significant components of the work.
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The CQA/QC Consultant is a party, independent from the Owner or Contractor, who is
responsible for observing, testing, and documenting the various activities comprising the
Reclamation Project in accordance with the CQA/QC Plan, the Technical Specifications and the
Drawings.
The CQA Officer will be responsible for overall implementation and management of the
CQA/QC Plan for the reclamation project.
The CQA Site Manager will be appointed by the CQA Consultant to provide day-to-day, on-
site oversight of the CQA/CQC activities. The CQA Manager could be a Denison employee or a
third-party consultant.
The CQA Consultant will utilize various QC Technicians to assist the on-site CQA Site
Manager to perform specific tasks through the project to verify the adequacy of construction
materials and procedures.
The Document Control Officer will be appointed by the Construction Manager to assist with
managing the various documents that will be produced throughout the project.
The CQA Laboratory is a party, independent from the Owner and Contractor, responsible for
conducting tests of soils and other project materials in accordance with ASTM and other
applicable standards in either an on-site or off-site laboratory.
The DRC Project Manager will represent the DRC's interests in the reclamation project.
The CQA/QC Plan (Attachment B of the 2011 Reclamation Plan) contains more detailed
descriptions of the project roles.
1.3 Scope of Work
The work outlined in these Technical Specifications consists of execution of the following tasks
associated with reclamation of the disposal cells and associated site reclamation.
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a. Preparation of borrow areas for material excavation by removal of vegetation; and
stripping, salvaging, and stockpiling of topsoil;
b. Preparation of material staging and stockpile areas by removal of vegetation; stripping,
salvaging, and stockpiling of topsoil; and providing for storm water diversion and
internal water collection;
c. Removal of raffinates and PVC liner materials from Cell 1 and placement within the last
active tailings cell;
d. Construction of a clay-lined disposal cell along the Cell 1 containment dike for disposal
of mill demolition debris and contaminated soils;
e. Construction of a sedimentation basin in the location of Cell 1;
f. Excavation of process area structure foundations, paved areas, concrete pads and
roadways, and placement of these materials in the disposal cell;
g. Excavation of contaminated subsoils from the process area, and placement in the last
active tailings cell or Cell 1.
h. Construction of the cover system over the tailings cells, with placement of rock mulch
and/or topsoil over the disposal cell cover surface.
i. Regrading and placement of topsoil over excavated areas, stockpile and staging areas,
and other disturbed areas of the site.
j. Establishment of vegetation on the disposal cell surface and surrounding reclaimed areas
on site.
Work not included in these Technical Specifications consists of salvage of facility equipment,
demolition of facility structures, groundwater monitoring and remediation, and post-reclamation
performance monitoring.
1.4 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 Owner’s radioactive
materials license. Geotechnical testing procedures shall conform to applicable ASTM standards,
as documented in the most current edition of standards in force at the start of work. Personnel
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safety procedures and monitoring shall be conducted in accordance with the Owner’s Radiation
Protection Manual for Reclamation and as directed by the Radiation Safety Officer (RSO).
1.5 Permits
The work will be conducted under the Owner’s existing radioactive materials license and State of
Utah Air Quality Approval Order (DAQE-AN1205005-06, issue date July 20, 2006). The
Contractor will be responsible for applying for, and obtaining (permit fees included), all other
necessary permits required to complete the work outlined in these Technical Specifications.
1.6 Inspection and Quality Assurance
In general, the QA/QC Plan details the Owner’s organizational structure and responsibilities,
qualifications of personnel, operating procedures and instructions, record keeping and document
control, and quality control in the sampling procedure and outside laboratory. The Plan will
adopt the existing quality assurance/quality control procedures utilized in compliance with the
existing license.
The RSO (and approved assistants as needed) will conduct on-site training, and full-time
personnel monitoring, and inspection of construction activities while the site reclamation work is
in progress. The RSO (and assistants) will be independent representatives of and appointed by
the Owner. The responsibilities and duties of the RSO shall be as outlined in the Owner’s
Protection Manual for Reclamation.
The CQA Manager (and approved assistants as needed) will provide full-time, on-site inspection
of all construction activities and quality assurance testing outlined in these Technical
Specifications and the CQA/QC Plan while the construction work is in progress. The CQA
Manager and assistants will be independent representatives of and appointed by the Owner. The
inspection and CQA testing conducted by the CQA Manager shall be under the supervision of
the Reclamation Project Manager. Inspection and CQA testing shall include the tasks described
in the CQA/QC Plan and listed below.
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a. Observation of construction practices and procedures for conformance with the
Technical Specifications.
b. Testing material characteristics to ensure that earthen materials used in the
construction conform to the requirements in the Technical Specifications.
c. Documentation of construction activities, test locations, samples, and test results.
d. Notification of results from quality assurance testing to the Owner and the Contractor.
e. Documentation of field design modifications or approved construction work that
deviates from the Technical Specifications.
The CQA Manager shall record the documentation outlined above on a daily basis. The
Reclamation Project Manager shall approve deviations from the Technical Specifications (if
necessary), with notification to the Owner and DRC or other appropriate Utah state regulatory
agency personnel. Quality control procedures have been developed for reclamation and
presented in Attachment B of this Reclamation Plan. Procedures will be used for testing,
sampling, and inspection functions.
1.7 Construction Documentation
During construction, the CQA Manager will record documentation of construction inspection
work on a daily basis. Documentation will include the following items.
a. Work performed by the Contractor.
b. CQA testing and surveying work conducted.
c. Discussions with the Owner and the Contractor.
d. Key decisions, important communications, or design modifications.
e. General comments including: weather conditions, work area surface conditions, and
visitors to the site.
All earthwork test results will be documented on a daily basis, with a copy of the results given to
the CQA Manager by the end of the following working day after the testing.
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The CQA Manager or his representative will take photographs of key construction activities and
critical items for documentation.
A final construction completion report, documenting the as-built conditions of the tailings
impoundment reclamation components will be submitted to DRC at the end of construction. This
report will include the following items.
a. All design modifications or changes to the Technical Specifications that were made
during construction.
b. An as-built layout of the facility prior to, and at the completion of reclamation
construction.
c. An as-built layout of other reclaimed areas of the site.
d. Documentation of soil cleanup verification work (soil radiation survey and soil sampling
and analyses) in areas of contaminated soil excavation.
e. Documentation of the revegetation work (soil amendments, seed mix, and vegetation
establishment).
1.8 Design Modifications
Design modifications (due to unanticipated site conditions or field improvements to the design)
will be made following the protocol outlined below.
a. Communication of modification with the Reclamation Project Manager.
b. Possible submittal to, and review by, DRC for approval.
c. Documentation of modification(s) in the construction completion report.
1.9 Environmental Requirements
The Contractor shall store materials, confine equipment, and maintain construction operations
according to applicable laws, 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 groundwater. If quantities of fuel, lubricating
oils or chemicals exceed the threshold quantities specified in Utah regulations, the Contractor
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shall prepare and follow a Spill Prevention Control and Countermeasures Plan (SPCCP), as
prescribed in applicable Utah regulations. The Owner shall approve said plan. Used lubricating
oils shall be disposed of or recycled at an appropriate facility. Disposal of all waste associated
with the project work will be the responsibility of the Contractor.
1.10 Water Management
The Contractor shall construct and maintain all temporary diversion and protective works
required to divert storm water 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.
Water required by the Contractor for dust suppression or soil-moisture conditioning shall be
obtained from the Owner.
1.11 Historical and Archeological Considerations
The Contractor shall immediately notify the Owner if materials of potential historical or
archeological significance are discovered or uncovered. The Owner 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 significance shall be protected as determined by appropriate
regulatory agencies, including removal or adjustment of work areas.
1.12 Health and Safety Requirements
Work outlined in these Technical Specifications shall be conducted under the Owner’s Radiation
Protection Manual for Reclamation, as directed by the RSO.
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 CQA Manager, Reclamation Project
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Manager, and RSO each have the authority to stop Contractor work if unsafe conditions or
deviations from Technical Specifications are observed.
1.13 Personnel Monitoring
Programs currently in place for monitoring of exposures to employees will remain in effect
throughout the time period during which tailings cell reclamation, mill decommissioning and
clean up of windblown contamination are conducted. These programs will include personal
monitoring and the ongoing bioassay program. 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. In general, no changes to the existing programs
are expected and reclamation activities are not expected to increase exposure potential beyond
the current levels. The Owner will assign an employee to act as RSO responsible for assuring
site workers comply with the Owner’s Radiation Protection Manual for Reclamation and the
requirements set forth in the Owner’s radioactive materials license.
1.14 Environmental Monitoring
Existing environmental monitoring programs will continue during the time period in which
reclamation and decommissioning is conducted. This includes monitoring of surface and
groundwater, airborne particulates, radon, soils and vegetation, according to the existing License
conditions. In general, no changes to the existing programs are expected and reclamation
activities are not expected to increase exposure potential beyond the current levels.
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2 SITE CONDITIONS
2.1 Site Location
The White Mesa mill site is located about 6 miles south of Blanding, Utah in San Juan County,
along County Road 191.
2.2 Climate and Geology
The climate of southeastern Utah is classified as dry to arid continental. Although varying
somewhat with elevation and terrain, the climate in the vicinity of the mill can be considered as
semi-arid with normal annual precipitation of about 13.3 inches. The mean annual relative
humidity is about 44 percent and is normally highest in January and lowest in July. The average
annual Class A pan evaporation rate is 68 inches (National Oceanic and Atmospheric
Administration and U.S. Department of Commerce, 1977), with the largest evaporation rate
typically occurring in July. (Denison, 2009)
The mill is located within the Blanding Basin of the Colorado Plateau physiographic province.
The average elevation of the site is approximately 5,600 ft (1,707 m) above mean sea level
(amsl). Typical of large portions of the Colorado Plateau province, the rocks underlying the site
are relatively undeformed. 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 fine-grained aeolian sands with a thickness varying from a few feet to
as much as 25 to 30 ft (7.6 to 9.1 m) across the site. The alluvium is underlain by the Dakota
Sandstone and Burro Canyon Formation, which are sandstones having total thicknesses ranging
from approximately 100 to 140 ft (31 to 43 m). (Denison, 2009)
2.3 Past Operations
The mill is a uranium/vanadium mill that was developed in the late 1970's by Energy Fuels
Nuclear, Inc. (“EFN”) as an outlet for the many small mines that are located in the Colorado
Plateau and for the possibility of milling Arizona strip ores. Construction on the tailings area
began on August 1, 1978. The mill was operated by EFN from the initial start-up date of May 6,
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1980 until the cessation of operations in 1983 and then intermittently under different ownership
through present-day. Denison (then named International Uranium (USA) Corporation), and its
affiliates, purchased the assets of EFN in May of 1997 and is the current owner of the facility.
2.4 Facilities Demolition
Demolition of equipment, structures, and associated facilities at the mill site will be conducted
according to applicable conditions of the radioactive materials license, the demolition plan for
the facility, and the Owner’s Radiation Protection Manual for Reclamation. Facilities demolition
is not included in this document.
2.5 Disposed Materials
The materials to be placed in the disposal and tailings cells consists of process waste materials,
structural debris, underlying liner materials, and subsoils from planned site cleanup activities.
Additional detail on each material type is outlined later in the Specification. The four major
types of materials are outlined below:
Raffinate Crystals – located in Cell 1,
Synthetic Liner – PVC liner from Cell 1,
Contaminated Soils - soils located in and around the mill site with concentrations
exceeding prescribed Radium-226 concentrations,
Mill Debris – all equipment and structures from the demolition of the mill.
2.6 Construction Materials
Construction materials for the disposal cell liner, cover system, and for erosion protection of the
cover and discharge channel will include soils and aggregates from on-site and off-site sources.
These materials are outlined below.
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2.6.1 Liner Materials
The disposal cell will be constructed, prior to the placement of contaminated soils and mill
demolition debris, with a compacted clay liner consisting of fine-grained soils. The fine-grained
soils will be obtained from suitable materials stockpiled on site during cell construction.
2.6.2 Random Fill
Random fill will be used within the disposal cell and tailings cells, placed on and around mill
material and debris and placed for the components of the cover system. Fill materials will be
obtained from soils stockpiled on site.
2.6.3 Topsoil
Topsoil for the surface of the disposal cell and surrounding areas to be revegetated will be
obtained from on-site stockpile areas.
2.6.4 Rock Mulch
A mixture of gravel and topsoil will be used in select areas on the cover. The mixture will be
25% gravel (with a D100 less than 1-inch) by weight. The sources of rock are nearby commercial
sources of alluvial gravel and cobbles. Rock mulch shall meet the particle-size distribution
requirements outlined in Section 8.
2.6.5 Erosion Protection and Perimeter Apron Material
A layer of rock will form the erosion protection zone on the side slopes and on the perimeter
apron of the disposal cell as well as within the discharge channel. The sources of rock are
nearby commercial sources of alluvial gravel and cobbles. Perimeter apron material shall meet
the particle-size distribution and durability requirements outlined in Section 8.
2.6.6 Filter Materials
Filter layer materials will be obtained from an off-site local commercial source or from select on-
site borrow areas. Riprap materials shall meet requirements for rock durability outlined in NRC
(1990) and Johnson (1999, 2002).
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2.6.7 Granular Materials
Granular materials will be used for filter material. Granular materials may also be used for
subsurface fill for the cell base. The sources of these materials are nearby commercial sources of
alluvial sand and gravel.
2.7 Staging and Stockpile Areas
Areas on site identified as staging areas or stockpile locations shall be approved by the Owner.
These areas will be constructed and used in a manner consistent with the Owner’s plans for
storm water management. The contractor shall maintain proper erosion control measures for
stockpiles and may be required to cover piles in situations where precipitation is anticipated.
2.8 Access and Security
Access to the site will be controlled at gated entrances through the existing restricted area
fencing. All gated entrances and security for Denison property will be maintained by the Owner.
2.9 Utilities
Utilities on site will be maintained by the Owner outside of work areas (areas to be demolished
or reclaimed). Utilities inside of work areas will be provided and maintained by the Contractor.
2.10 Sanitation Facilities
The Contractor, in accordance with the Owner’s Radiation Protection Manual for Reclamation,
will maintain sanitation facilities required during construction.
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3 WORK AREA PREPARATION
3.1 General
This Section describes the preparation of site areas for reclamation. This work will be conducted
according to applicable sections of the Owner’s Radiation Protection Manual for Reclamation.
3.2 Water Management
Preparation for work in the site area will include the water management tasks outlined below.
a. Removal of raffinate crystals from Cell 1.
b. Breach Cell 1 and construct the cell as a sedimentation basin. Re-route runoff from the
mill area and areas immediately north of the cell into the sedimentation basin for
discharge onto the natural ground via the channel to be located at the southwest corner of
the basin.
c. Diversion of clean area storm water runoff from work areas (where facilities demolition
and material excavation will take place) and from the disposal cell footprint area.
d. Collection of storm water runoff from within the work areas and the disposal cell
footprint for treatment and permitted discharge, or for disposed material compaction or
dust control. The planned storage location for this affected storm water is the
sedimentation pond.
e. Isolation of water used for processing operations associated with reclamation from storm
water runoff.
f. Water from processing operations or other contaminated water will not be used for
disposal cell construction.
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3.3 Cell Construction
A clay lined disposal area will be constructed adjacent to and parallel with the existing Cell 1
dike for permanent disposal of contaminated material and debris from the mill site
decommissioning and the Cell 1 Tailings Area. The area will be lined with a 12-inch thick layer
of compacted clay prior to placement of contaminated materials and installation of the final
reclamation cap.
3.4 Soil Borrow Areas
Disposal cell fill and liner materials will be excavated from among the identified borrow areas on
site. Cover and liner soil will be from suitable materials stockpiled on site during cell
construction.
The use of specific soil borrow areas will be selected based on haul distance to the disposal cell,
ease of excavation of cover material, geotechnical characteristics, uniformity of the borrow
material, and acceptable radiological and geochemical characteristics.
Borrow area preparation will consist of setup for storm water management (Section 3.2) and
clearing and stripping (Section 3.5).
3.5 Clearing and Stripping
For work areas that are vegetated, preparation work will include the tasks outlined below.
3.5.1 Clearing
Clearing of vegetation and grubbing of roots will be in identified work areas. Clearing and
grubbing shall not extend beyond 20 feet from the edge of the work area, unless as shown on the
Drawings or as approved by the Reclamation Project Manager.
Vegetation from clearing and grubbing may be shredded or chipped to form mulch. Alternative
methods of on-site or off-site disposal or burning of stripped vegetation shall be conducted only
as approved by the Reclamation Project Manager.
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3.5.2 Stripping
Stripping of salvageable topsoil (if present) shall be done within the entire work area. Stripping
of topsoil shall not extend beyond 10 feet from the edge of the work area, unless approved by the
Reclamation Project Manager. The depth of stripping of reclamation soil shall be based on the
presence of suitable topsoil and approved by the Reclamation Project Manager. Water shall be
added to the area of excavation if the soils are dry and stripping work is generating dust.
Topsoil shall be stockpiled in approved stockpile areas. The final stockpile surface shall be
graded and smoothed to minimize erosion and facilitate interim revegetation of the stockpile
surfaces.
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4 CELL 1 DISPOSAL AREA BASE CONSTRUCTION
4.1 General
This section outlines the work associated with construction of the disposal cell base for receipt of
materials (as described in Section 7.0) within Cell 1. The base of the disposal cell will be lined
with a compacted clay liner. The cell base will be constructed as shown on the Drawings and
outlined in these Technical Specifications.
4.2 Materials Description
4.2.1 Subgrade Fill
The disposal cell footprint is likely to have an irregular surface from areas that have been
excavated. Low areas of the excavated surface should be filled to form a smooth, competent
foundation for clay liner construction. Subgrade fill will be used in excavated areas of the
disposal cell footprint to meet desired grades and elevations for the disposal cell foundation
(shown on the Drawings).
Subgrade fill may consist of off-site granular materials, or soils and weathered sedimentary rock
from approved on-site excavation areas. Subgrade fill shall be minus 6-inch size, and shall be
free from roots, branches, rubbish, and process area debris.
4.2.2 Clay Liner Material
Clay liner material shall be minus 1-inch size, and shall be free from roots, branches, rubbish,
and process area debris. Clay liner material shall have a minimum of 40 percent passing the No.
200 sieve and a minimum plasticity index (PI) of 15%. Suitable materials will classify as CL,
CH, or SC materials under the Unified Soil Classification System.
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4.3 Work Description
4.3.1 Foundation Preparation
The footprint of the disposal cell shall form a competent foundation for clay liner and cover
construction. The surface of the disposal cell footprint shall be filled (where required) in low
areas to form a smooth, competent foundation for clay liner and cover construction. Subgrade
fill (Section 4.2.1) shall be placed in lifts and compacted in excavated areas of the disposal cell
footprint to meet desired grades and elevations for the disposal cell foundation (shown on the
Drawings). The final filled surface shall be compacted with approved construction equipment to
provide a foundation surface with uniform density for clay liner placement.
4.3.2 Disposal Cell Foundation Area
The footprint of the disposal cell is established along the north side of the tailings dike along the
south edge of Cell 1 (shown on the Drawings).
4.3.3 Subgrade Fill Placement
Subgrade fill (Section 4.2.1) shall be placed in lifts and compacted in excavated areas of the
disposal cell footprint to meet desired grades and elevations for the disposal cell foundation.
Subgrade fill may be (1) granular material from off-site commercial sources, or (2) soils and
weathered sedimentary rock from approved on-site excavation areas.
4.3.4 Clay Liner Material Placement
Clay liner material (Section 4.2.2) shall be placed in lifts with maximum compacted thickness of
6 inches to form a continuous layer with a total minimum compacted layer thickness of 12
inches. Clay liner material shall be placed over the prepared subgrade surface of the disposal
cell (Section 4.3.1).
Compaction of the clay liner material shall be done with a sheepsfoot or tamping-foot roller of
sufficient weight to achieve the required compaction specifications. Rubber-tired equipment
shall not be used solely to compact the clay liner material.
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If the moisture content of any layer of clay liner is outside of the allowable placement moisture
content range specified, the material shall be moistened and/or reworked with a harrow, scarifier,
or other suitable equipment to a sufficient depth to provide relatively uniform moisture content
and a satisfactory bonding surface before the next succeeding layer of clay material is placed. If
the compacted surface of any layer of clay liner material is too wet (due to precipitation), for
proper compaction of the fill material to be placed thereon, it will be reworked with a harrow,
scarifier or other suitable equipment to dry out the layer and reduce the moisture content to
within the required limits and recompacted.
The layers of the placed clay liner will be such that the liner will, as far as practicable, be free of
lenses, pockets, streaks or layers of material differing substantially in texture, gradation or
moisture content from the surrounding material. Oversized material will be controlled through
selective excavation of stockpiled material, observation of placement by a qualified individual
with authority to stop work and reject material being placed and by culling oversized material
from the fill.
No clay liner material will be placed when either the materials, or the underlying material, is
frozen or when ambient temperatures do not permit the placement or compaction of the materials
to the specified density, without developing frost lenses in the fill.
Any holes in the clay liner material resulting from testing should be repaired by hand by filling
with clay fill, or by filling with bentonite powder which is hydrated to fully seal the hole.
4.4 Performance Standards and Testing
Test results indicating dry densities less than the specified values will be rejected. Such rejected
material shall be reworked by the contractor as necessary and rerolled until a dry density equal to
or greater than the specified percent of standard Proctor maximum density is attained. Material
that is too dry or too wet to permit bonding of layers during compaction will be rejected and shall
be reworked by the contractor until the moisture content is within the specified limits.
Reworking may include removal, re-harrowing, reconditioning, rerolling, or combinations of
these procedures.
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4.4.1 Subgrade Testing
Where required, checking of compaction of compacted subgrade fill and the final subgrade
surface shall consist of a minimum of one field density test per 1,000 cubic yards of material
compacted. A minimum of two tests will be taken for each day that an applicable amount of fill
is placed in excess of 150 cubic yards. A minimum of one test per lift and at least one test for
every full shift of compaction operations will be taken.
Field density tests shall be compared with standard Proctor tests (ASTM D698 Method A or C).
Where required, standard Proctor or Maximum Index Density tests shall be conducted at a
frequency of at least one test per 5,000 cubic yards of material compacted, or when material
characteristics show significant variation.
Field density testing may be conducted with the sand cone test (ASTM D1556) or a nuclear
density gauge (ASTM D6938, or as modified by the QA Manager). Correlation of nuclear
density gauge results shall be by comparison with results from sand cone test(s) and laboratory
testing for water content(s) using the oven drying method (ASTM D2216) on similar material.
Subgrade fill will be placed in lifts not exceeding 8 inches in loose thickness. Each lift shall be
compacted to a minimum of 90 percent of standard Proctor (ASTM D698) density and within
three percent of the optimum moisture content for the material.
4.4.2 Clay Liner Testing
Material specifications for the clay liner material shall be confirmed by gradation testing
conducted by approved personnel. Testing shall consist of No. 200 sieve wash and maximum
particle size testing (ASTM D422), and Atterberg limits testing (ASTM D4318) on samples of
clay liner materials, at a frequency of at least one test per 1,000 cubic yards of fill placed, or
when material characteristics show a significant variation.
Checking of compaction of the clay liner material shall consist of a minimum of one field density
test per 500 cubic yards of material compacted. A minimum of two tests will be taken for each
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day that an applicable amount of fill is placed in excess of 150 cubic yards. A minimum of one
test per lift and at least one test for every full shift of compaction operations will be taken.
Field density tests shall be compared with Standard Proctor tests (ASTM D698 Method A or C)
on the same material. Standard Proctor tests shall be conducted at a frequency of at least one test
per 2,500 cubic yards of material compacted, or when material characteristics show significant
variation.
Field density testing may be conducted with the sand cone test (ASTM D1556) or a nuclear
density gauge (ASTM D6938, or as modified by the QA Manager). Correlation of nuclear
density gauge results shall be by comparison with results from sand cone test(s) and laboratory
testing for water content(s) using the oven drying method (ASTM D2216) on similar material.
Each lift of clay liner material shall be compacted to at least 95 percent of the maximum dry
density for the material, as determined by the standard Proctor test (ASTM D698). During
compaction, the material shall be within 2 percent above to 2 percent below optimum moisture
content for the material, as determined by the standard Proctor test. If water addition is required
to achieve this range of moisture contents, the added water shall be thoroughly mixed into the
material prior to compaction.
4.4.3 Grading Tolerances
The completed grading for the clay liner shall be within 1.0 foot (horizontally) of the lines as
designed, and within 0.1 foot (vertically) of the elevations as designed. The final surfaces shall
be smoothed to avoid abrupt changes in surface grade or areas of runoff concentration. The layer
thicknesses shall meet the required minimum thicknesses.
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5 DISCHARGE CHANNEL GRADING
5.1 General
This section outlines specifications for the work associated with excavating the discharge
channel into competent bedrock. Portions of the grading for the sedimentation basin may be in
soil, while other areas may require rock excavation. In general, the rock is believed to be
rippable, however the Contractor should account for the possibility that harder rock may be
encountered in the excavation areas.
5.2 Work Description
5.2.1 Discharge Channel Excavation
The discharge channel shall be excavated to the slopes and grades shown on the Drawings. The
channel width(s) shall be constructed to the dimensions shown on the Drawings. The side slopes
of the channel shall be 3:1 (horizontal to vertical).
Discharge channel excavation will include breaching of the Cell 1 embankment on the east side.
Riprap will not be required to armor the discharge channel because the channel excavation will
extend into competent sedimentary rock. The competency of the sedimentary rock must be
verified, in the field, by the CQA Manager.
5.2.2 Grading Tolerances
The completed grading for the sedimentation basin, in soil, shall be within 1.0 foot (horizontally)
of the lines as designed, and within 0.1 foot (vertically) of the elevations as designed. The final
surfaces shall be smoothed to avoid abrupt changes in surface grade or areas of runoff
concentration.
The completed grading for the discharge channel (and portions of the sedimentation basin) in
rock shall be within 2.0 foot (horizontally) of the lines as designed, and within 0.5 foot
(vertically) of the elevations as designed. The final rock surfaces will be rough and should not be
filled to make grade. The bedrock channel should be constructed at or below the design grades
in order to meet the intent of the design.
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6 MILL DECOMMISSIONING
The following subsections describe decommissioning plans for the mill buildings and equipment,
the mill site, and associated windblown contamination.
6.1 Mill Buildings and Equipment
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 will 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 leach 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;
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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;
The decontamination pads;
The office building;
The shop and warehouse building;
The sample plant building; and
The reagent storage building.
The sequence of demolition will proceed so as to allow the maximum use of support areas of the
facility such as the office and shop areas. It is anticipated that all major structures and large
equipment will be demolished with the use of hydraulic shears. This equipment will speed the
process, provide proper sizing of the materials for transport and placement, and reduce exposure
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to radiation and other safety hazards during the demolition. Any uncontaminated or
decontaminated equipment to be considered for salvage will be released in accordance with the
terms of License Condition 9.10. As with the equipment for disposal, any contaminated soils
from the mill area will be disposed of in the tailings cells in accordance with Section 7.0 of the
Technical Specifications.
6.2 Mill Site
Contaminated areas around the mill site are expected to 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. All contaminated materials will
be excavated and be disposed in one of the tailings cells in accordance with Section 7.0 of these
Technical Specifications. The depth of excavation will vary depending on the extent of
contamination and will be based on the criteria in Section 7.2.3 of these Technical
Specifications. All other 11e.(2) byproduct materials will be disposed of in the tailings cells.
All ancillary contaminated materials including pipelines will be removed and will be disposed of
by disposal in the tailing cells in accordance with Section 7.0 of these Technical Specifications.
Disturbed areas will be covered, graded and vegetated as required and shown on the plans.
6.3 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.
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6.4 Guidance
The necessity for remedial actions will be based upon an evaluation prepared by the Owner, and
approved by the DRC, of the potential health hazard presented by any windblown materials
identified. The assessment will be based upon analysis of all pertinent radiometric and past land
use information and will consider the feasibility, cost-effectiveness, and environmental impact of
the proposed remedial activities and final land use. All methods utilized will be consistent with
the guidance contained in NUREG-5849: "Manual for Conducting Radiological Surveys in
Support of License Termination."
6.5 General Methodology
The facility currently monitors soils for the presence of Ra-226, Th-230, and natural uranium,
such results being presented in the second semi-annual effluent report for each year. Guideline
values for these materials will be determined and will form the basis for the cleanup of the mill
site and surrounding areas. For purposes of determining possible windblown contamination,
areas used for processing of uranium ores as well as the tailings and evaporative facilities will be
excluded from the initial scoping survey, due to their proximity to the uranium recovery
operations. Those areas include:
The mill building, including CCD, Pre-Leach Thickener area, uranium drying and
packaging, clarifying, and preleach;
The SX building, including reagent storage immediately to the east of the SX building;
The alternate feed circuit;
The ore pad and ore feed areas;
Tailings Cells No. 2, 3, 4A, and 4B; and
Evaporation Cell No. 1.
The remaining areas of the mill will be divided up into two areas for purposes of windblown
determinations:
The restricted area, excluding the areas listed above; and
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A halo around the restricted area.
6.6 Scoping Survey
Areas within the restricted area will be initially surveyed on a 30 x 30 meter grid as described
below. The halo around the suspected area of contamination will be initially surveyed on a 50 x
50 meter grid using the methodologies described. Any areas which are found to have elevated
activity levels will be further evaluated. Initial surveys of the areas surrounding the mill and
tailings area have indicated potential windblown contamination only to the north and east of the
ore storage area, and to the southwest of Cell 3.
Areas contaminated through process activities or windblown contamination from the tailings
areas will be remediated to meet applicable cleanup criteria for Ra-226, Th-230, and natural
uranium. Contaminated areas will be remediated such that the residual radionuclides remaining
on the site, that are distinguishable from background, will not result in a dose that is greater than
that which would result from the radium soil standard (5 pCi/g above background).
Soil cleanup verification will be accomplished by use of several calibrated beta/gamma
instruments. Multiple instruments will be maintained and calibrated to ensure availability during
Remediation efforts.
Initial soil samples will be chemically analyzed to determine on-site correlation between the
gamma readings and the concentration of radium, thorium and uranium, in the samples. Samples
will be taken from areas known to be contaminated with only processed uranium materials (i.e.
tailings sand and windblown contamination) and areas in which it is suspected that unprocessed
uranium materials (i.e. ore pad and windblown areas downwind of the ore pad) are present. The
actual number of samples used will depend on the correlation of the results between gamma
readings and the Ra-226 concentration. A minimum of 35 samples of windblown tailings
materials and 15 samples of unprocessed ore materials is proposed.
Adequate samples will be taken to ensure that graphs can be developed to adequately project the
linear regression lines and the calculated upper and lower 95 percent confidence levels for each
of the instruments. The 95 percent confidence limit will be used for the guideline value for
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correlation between gamma readings and radium concentration. Because the unprocessed
materials are expected to have proportionally higher values of uranium in relation to the radium
and thorium content, the correlation to the beta/gamma readings are expected to be different than
readings from areas known to be contaminated with only processed materials. Areas expected to
have contamination from both processed and unprocessed materials will be evaluated on the
more conservative correlation, or will be cleaned to the radium standard which should ensure
that the uranium is removed.
Radium concentration in the samples should range from 25% of the guideline value (5 pCi/g
above background) for the area of interest, through the anticipated upper range of radium
contamination. Background radium concentrations have been gathered over a 16-year period at
sample station BHV-3 located upwind and 5 miles west of the mill. The radium background
concentration from this sampling location is 0.93 pCi/g. This value will be used as an interim
value for the background concentration. Prior to initiating cleanup of windblown contamination,
a systematic soil sampling program will be conducted in a geologically similar (soil types and
soil chemistry) area within 3 miles of the site that is similar to the areas to be cleaned, to
determine the average background radium concentration, or concentrations, to be ultimately used
for the cleanup.
An initial scoping survey for windblown contamination will be conducted based on analysis of
all pertinent radiometric and past land use information. The survey will be conducted using
calibrated beta/gamma instruments on a 30 meter by 30 meter grid. Additional surveys will be
conducted in a halo, or buffer zone, around the projected impact area. The survey in the buffer
area will be conducted on a 50 meter by 50 meter grid. Grids where no readings exceed 75% of
the guideline value (5 pCi/g above background) will be classified as unaffected, and will not
require remediation.
The survey will be conducted by walking a path within a grid as shown on Figure A-1. The
paths are designed so that a minimum of 10% of the area within the grid sidelines will be
scanned, using an average coverage area for the instrument of one meter wide. The instrument
will be swung from side to side at an elevation of six inches above ground level, with the rate of
coverage maintained within the recommended duration specified by the specific instrument
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manufacturer. In no case will the scanning rate be greater than the rate of 0.5 meters per second
(m/sec) specified in NUREG/CR-5849 (NRC, 1992).
6.7 Characterization and Remediation Control Surveys
After the entire sub-area has been classified as affected or unaffected, the affected areas will be
further scanned to identify areas of elevated activity requiring cleanup. Such areas will be
flagged and sufficient soils removed to, at a minimum, meet activity criteria. Following such
remediation, the area will be scanned again to ensure compliance with activity criteria. A
calibrated beta/gamma instrument capable of detecting activity levels of less than or equal to 25
percent of the guideline values will be used to scan all the areas of interest.
6.8 Final Survey
After removal of contamination, final surveys will be taken over remediated areas. Final surveys
will be calculated and documented within selected, specific ten meter by ten meter grids with
sample point locations, as shown in Figure A-2. Soil samples from 10% of the surveyed grids
will be chemically analyzed to confirm the initial correlation factors utilized and confirm the
success of cleanup effort for radium, thorium and uranium. Ten percent of the samples
chemically analyzed will be split, with a duplicate sent to an off-site laboratory. Spikes and
blanks, equal in number to 10% of the samples that are chemically analyzed, will be processed
with the samples.
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----------.......
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1-------------10m
LOCATION OF SYSTEMATIC SOIL SAMPLING
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Denison Mines (USA) Corp
mu
WHITE MESA MILL TAILINGS RECLAMATION
STANDARD SAMPLING PATIERN FOR
SYSTEMATIC SURVEY OF SOIL
10 m
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6.9 Employee Health and Safety
Programs currently in place for monitoring of exposures to employees will remain in effect
throughout the time period during which tailings cell reclamation, mill decommissioning and
clean up of windblown contamination are conducted. This will include personal monitoring and
the ongoing bioassay program. 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. In general, no changes to the existing programs are expected and
reclamation activities are not expected to increase exposure potential beyond the current levels.
6.10 Environment Monitoring
Existing environmental monitoring programs will continue during the time period in which
reclamation and decommissioning is conducted. This includes monitoring of surface and
groundwater, airborne particulates, radon, soils and vegetation, according to the existing License
conditions. In general, no changes to the existing programs are expected and reclamation
activities are not expected to increase exposure potential beyond the current levels.
6.11 Quality Assurance
In general, the QA/QC Plan details the Owner’s organizational structure and responsibilities,
qualifications of personnel, operating procedures and instructions, record keeping and document
control, sampling procedures and outside laboratory testing.
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7 MATERIAL DISPOSAL
7.1 General
This section outlines the work associated with placement of materials in the disposal cell and
tailings cells.
7.2 Materials Description
The types of materials to be disposed of are outlined below.
7.2.1 Raffinate Crystals
After the residual liquid in Cell 1 has been evaporated, the contractor will remove the raffinate
crystals from Cell 1 and move them to the tailings disposal cells. The crystals are likely to have
the consistency of a granular material with larger crystal masses which may require being broken
down for loading and transport (using the loading equipment).
7.2.2 Synthetic Liner
The existing PVC liner shall be removed from Cell 1 and disposed of in the tailings disposal
area.
7.2.3 Contaminated Soils
Soils located in and around the mill site with concentrations of Radium-226 averaged over any
area of 100 square meters exceeding the background level by more than:
5 pCi/g averaged over the first 15 cm of soils below the surface, and
15 pCi/g averaged over a 15 cm thick layer of soils more than 15 cm below the
surface;
The contaminated soils will be placed in the tailings disposal cells. Soils excavated from Cell 1
shall be placed in the tailings disposal cells.
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7.2.4 Mill Debris
The mill debris will include all equipment, including tankage and piping, agitation equipment,
process control instrumentation and switchgear, and contaminated structures; including concrete
structures and foundations, will be placed in the disposal cell.
7.3 Work Description
The materials described will be spread over the working surface as much as possible to provide
relatively uniform settlement and consolidation characteristics of the cleanup materials.
7.3.1 Raffinate Crystals
Raffinate crystals will be removed from Cell 1 and transported to the tailings cells. Placement of
the crystals will be performed as a granular fill, with care being taken to avoid nesting of large
sized material. Voids around large material will be filled with finer material or the crystal mass
will be broken down by the equipment. Actual placement procedures will be evaluated by the
QC officer during construction as crystal materials are placed in the cells and modified with the
agreement of the DRC.
7.3.2 Synthetic Liner
The PVC liner will be cut, folded (when necessary), removed from Cell 1, and transported to the
tailings cells. The liner material will be spread as flat as practical over the designated area.
After placement, the liner will be covered as soon as possible with at least one foot of soil,
crystals or other materials for protection against wind uplift, as approved by the CQA Manager.
7.3.3 Contaminated Soils
The extent of contamination of the mill site will be determined by a scintillometer survey. If
necessary, a correlation between scintillometer readings and U-nat/Radium-226 concentrations
will be developed. Scintillometer readings can then be used to define cleanup areas and to
monitor the cleanup. Soil sampling will be conducted to confirm that the cleanup results in
levels that meet the criteria described in 7.2.3.
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Where surveys indicate the above criteria have not been achieved, the soil will be removed to
meet the criteria. Soil removed from Cell 1 will be excavated and transported to the tailings
cells.
7.3.4 Mill Debris
Placed debris will be spread across the bottom of the disposal cell to avoid nesting and to reduce
the volume of voids present in the disposed mass. Stockpiled soils and/or other approved
materials will be placed over and into the scrap in sufficient amount to fill the voids between the
large pieces and the volume within the hollow pieces to form a coherent mass. It is recognized
that some voids will remain because of the scrap volume reduction specified, and because of
practical limitations of these procedures. Reasonable effort will be made to fill the voids. The
approval of the CQA Manager or a designated representative will be required for the use of
materials other than stockpiled soils for the purpose of filling voids.
7.3.5 Material Sizing and Preparation
Demolition debris to be placed in the disposal cell will consist of equipment and structural
material from facilities demolition. The demolition procedures are outlined in the Preliminary
Mill Decommissioning Plan. Because of the wide variety in shape and size of demolition debris,
material of odd shapes will be cut or dismantled, to the extent practical, prior to disposal, to
facilitate handling and placement and minimize void spaces in the disposal cell. The maximum
size of dismantled or cut materials shall not exceed 20 feet in the longest dimension and a
maximum volume of 30 cubic feet for placement in the cells. Smaller dimensions may be
necessary for loading, handling, hauling, and placement of material in the disposal cell.
The debris, after having been reduced in dimension and volume, if required, will be placed in the
tailings cells as directed by the CQA Manager.
7.3.6 Incompressible Debris
Material that is not compressible (steel columns and beams, concrete, and other solid material)
shall be reduced in size for loading, hauling, and placement in the disposal cell. Incompressible
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debris shall be placed, oriented, or spread in a manner that minimizes void spaces below,
between, and above these materials. Incompressible debris shall be placed on and covered with
soils or similar materials (Specification Section 7.3.3). Incompressible debris such as steel
members shall be placed in the disposal cell with the longest dimension oriented horizontally.
Thick-walled pipe, conduit, tanks, vats, pressure vessels, and other hollow materials that cannot
be crushed or dismantled shall be transported to the planned location within the disposal cell and
oriented for filling and burial. The voids on the inside of the item shall be filled with sand or
grout (controlled low-strength material, flowable fill, etc.). Contaminated soil (Section 7.3.3) or
sand will be placed outside of the items and compacted with standard compaction equipment
(where possible) or hand-operated equipment to the compaction requirements in Specification
Section 7.4. Several lifts of compacted contaminated soil may be necessary to fill around and
cover these items.
7.3.7 Compressible Debris
Materials that are compressible (such as thin-walled piping and thin-walled tanks) shall be
flattened or crushed in the disposal cell, prior to final placement. Flattening or crushing shall be
done with hydraulic excavator attachments, or with a dozer or other steel-tracked equipment.
These materials shall be placed in the disposal cell and spread to form a lift with a maximum
thickness of two feet. Spreading shall be done in a manner resulting in materials laying flat and
minimizing void spaces. All pipe that shall be cut into lengths of approximately 10 feet or less
for disposal. Pipe larger than 12 inches in diameter shall be longitudinally split or cut.
7.3.8 Organic Debris
The volume of organic materials (such as wood and paper) that may be prone to long-term
biodegradation within the cell is anticipated to be a small percentage of the material being
disposed. However, to limit the potential for settlement due to consolidation of organics, the
contractor shall not dispose of organic materials in any lift thicker than 12 inches. The material
shall be spread with a dozer in lifts, or thoroughly mixed with soil that will be placed around
incompressible debris, and compacted.
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7.3.9 Soils and Similar Materials
Soils and soil-like materials to be placed in the disposal cell will be from on-site areas identified
by the Owner for excavation. Soil or soil-like material shall be placed and compacted over each
lift of debris (Section 7.2.4) or other materials in lifts not to exceed two feet in loose thickness
and compacted prior to placement of additional lifts. Soils will also be used for interim soil
cover to minimize exposure of demolition materials and other materials to air and meteoric
water.
7.4 Performance Standards and Testing
7.4.1 Material Compaction – Debris Lifts
During construction, the compaction requirements for the crystals will be evaluated based on
field conditions and material quantities. The compaction requirements will be determined by the
CQA Manager and the Reclamation Project Manager or a designated representative, with the
agreement of the Owner.
The debris, contaminated soils and other materials for the first lift will be placed to a depth of up
to four feet thick, in a bridging lift, to allow access for placing and compacting equipment. The
first lift will be compacted by the tracking of heavy equipment, such as a Caterpillar D6 Dozer
(or equivalent), using at least 4 passes, prior to the placement of the next lift. Subsequent lifts
will not exceed 12 inches and will be compacted using a minimum of 4 passes with the tracked
equipment.
Soil or similar material shall be compacted with a minimum of 6 passes with self-propelled,
towed, or hand-held vibratory compaction equipment. The number of passes shall be confirmed
with actual compaction equipment on site with a field test section of soil to establish a
correlation between the field compaction method and 80 percent of maximum dry density for the
soil, as determined by the Standard Proctor test (ASTM D698). During compaction, the material
shall be within 1 percent above to 4 percent below optimum moisture content for the material, as
determined by the Standard Proctor test. If water addition is required to achieve this range of
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moisture contents, the added water shall be thoroughly mixed into the material prior to
compaction.
The CQA technicians will monitor and approve of the final debris placement. In areas where
voids are observed during placement, the contractor shall re-excavate the area, fill any voids
encountered with soil and recompact the materials, or grout the voids.
7.4.2 Material Compaction - Disposed Materials
The upper 12 inches of the final disposed material surface shall be compacted to 90 percent of
the maximum dry density for the material, as determined by the Standard Proctor test. During
compaction, the material shall be within 1 percent above to 4 percent below optimum moisture
content for the material, as determined by the Standard Proctor test. If water addition is required
to achieve this range of moisture contents, the added water shall be thoroughly mixed into the
material prior to compaction.
7.4.3 Testing Frequency
Field density tests shall be compared with Standard Proctor tests (ASTM D698 Method A or C)
on the same material. Standard Proctor tests shall be conducted at a frequency of at least one test
per 5,000 cubic yards of material compacted, or when material characteristics show significant
variation.
Field density testing may be conducted with the sand cone test (ASTM D1556) or a nuclear
density gauge (ASTM D6938, or as modified by the QA Manager). Correlation of nuclear
density gauge results shall be by comparison with results from sand cone test(s) and laboratory
testing for water content(s) using the oven drying method (ASTM D2216) on similar material.
The frequency of the field density and moisture tests will be not less than one test per 1,000
cubic yards of compacted fill. A minimum of two tests will be taken for each day that an
applicable amount of fill is placed in excess of 150 cubic yards. A minimum of one test per lift
and at least one test for every full shift of compaction operations will be taken.
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7.4.4 Final Slope and Grades
The final disposed material surface shall have maximum side slopes of 5:1 and a top surface
sloping in the directions and grades shown on the Drawings. The side slopes and top surface
shall be free from abrupt changes in grade or areas of runoff concentration. The final disposed
material surface shall be compacted with approved construction equipment to form a smooth
surface with uniform density for subsequent cover placement.
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8 COVER CONSTRUCTION
8.1 General
This section outlines the work associated with construction of the earthen cell cover. A multi-
layered earthen cover will be placed over tailings Cells 2, 3 and 4A and a portion of Cell 1 used
for disposal of contaminated materials (the Cell 1 Tailings Area).
8.2 Materials Description
8.2.1 Cover Random Fill
The random fill for the radon attenuation layers, and the water storage/frost protection layer will
consist of a mixture of sands and silts with varying amounts of clay.
In the initial bridging (platform) lift of the tailings, rock sizes of up to 2/3 of the thickness of the
lift will be allowed. On all other fill lifts, rock sizes will be limited to 2/3 of the lift thickness,
with at least 30 percent of the material finer than the no. 40 sieve. The portion passing the no. 40
sieve, will classify as CL, SC, ML or SM materials under the Unified Soil Classification System.
Oversized material will be controlled through selective excavation at the stockpiles and through
the utilization of a grader, bulldozer or backhoe to cull oversize materials from the fill.
The source of these materials will be on-site stockpiles from previous cell construction activities.
8.2.2 Organic Matter Amendment
The organic matter amendment Biosol® will be used to amend the properties of the water
storage/frost barrier fill for plant growth. The current amendment proposal is to add 1.5
tons/acre of Biosol®, however the final amount will be based on analysis of the soils during
construction.
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8.2.3 Rock Mulch
Gravel will be mixed with topsoil and placed on portions of the cover on Cells 2, 3, 4A, and 4B
top surfaces (as shown on the Drawings) for erosion protection. Rock mulch material shall be
shall be free from roots, branches, rubbish, and debris.
The rock portion of the rock mulch will consist of granular materials from approved off-site
areas. The mixture shall be 25% gravel by weight. The rock (gravel) portion of the rock mulch
shall be a screened product and have a D100 particle size of less than 1-inch (100% passing the 1-
inch sieve).
The soil portion of the rock mulch will consist of select material from the on-site topsoil borrow
area (Section 3.5).
8.2.4 Erosion Protection and Perimeter Apron Rock
Material for the perimeter apron erosion protection will consist of granular materials from
approved off-site sources. The perimeter apron rock will be placed along the toe of the disposal
cell and the tailings cells in the erosion protection areas (as shown on the Drawings). Perimeter
apron rock shall meet NRC long-term durability requirements (a rock quality designation of 65
or more).
Perimeter apron rock shall be shall be a screened product, free from roots, branches, rubbish, and
debris. The specifications as given below are for rock quality designations of 70 or higher. If
actual rock quality designation is between 65 and 69, oversizing will be required. Rock quality
designations below 65 will not be acceptable.
Designated gradations for the apron rock will be specified on the final drawings for construction.
Apron rock will be imported from off-site.
Side Slope riprap will have a minimum D50 of 7.4 in.;
Rock Apron #1 will have a minimum D50 of 7.4 in.,
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o Minimum layer thickness of 24 inches;
Rock Apron #2 will have a minimum D50 of 15 in.,
o Minimum layer thickness of 45 inches.
8.2.5 Erosion Protection Filter
Erosion protection filter material shall be shall be free from roots, branches, rubbish, and debris.
The filter material will generally classify as sand containing gravel and fines and shall meet the
following gradation specifications.
Table 8.1 – Filter Material Gradation
Sieve Size Percent Passing,
By Weight
3-inch 100
No. 4 70-100
No. 20 35-70
No. 200 5-15
8.2.6 Topsoil
Topsoil will consist of select material from the designated, on-site topsoil borrow area (Section
3.5). The topsoil shall have a plasticity index (PI) less than 10 (%), as determined by Atterberg
limits testing.
8.3 Work Description
The contractor will place cover materials based on a schedule determined by the Owner and the
Owner’s analysis of settlement data, piezometer data and equipment mobility considerations.
The DRC must approve fill grades and elevations prior to placement of final cover materials.
Settlement monitoring points (both temporary and permanent) will be established and monitored
in accordance with Sections 8.3.1 to 8.3.3 of the Technical Specifications and the Settlement
Monitoring Plan approved by DRC for the site.
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In each layer of the cover, the distribution and gradation of the materials throughout each fill
layer will be such that the fill will, as far as practicable, be free of lenses, pockets, or layers of
material differing substantially in texture, gradation or moisture content from the surrounding
material. Nesting of oversized material will be controlled through selective excavation of
stockpiled material, observation of placement by a qualified individual with authority to stop
work and reject material being placed and by culling oversized material from the fill utilizing a
grader. Successive loads of material will be placed on the fill so as to produce the best practical
distribution of material.
If the compacted surface of any layer of fill is too dry or smooth to bond properly with the layer
of material to be placed thereon, it will be moistened and/or reworked with a harrow, scarifier, or
other suitable equipment to a sufficient depth to provide relatively uniform moisture content and
a satisfactory bonding surface before the next succeeding layer of fill is placed. If the compacted
surface of any layer of fill in-place is too wet, due to precipitation, for proper compaction of the
fill material to be placed thereon, the contractor will rework the material with a harrow, scarifier
or other suitable equipment to reduce the moisture content to the specified range. The contractor
will then recompact the fill.
No material will be placed when either the material being compacted, or the underlying material,
is frozen or when ambient temperatures do not permit the placement or compaction of the
materials to the specified density, without developing frost lenses in the fill.
8.3.1 Monitoring Interim Cover Settlement
The contractor will maintain the existing settlement monitoring points located within tailings
disposal cells by extending them through additional fill placement. For areas without settlement
monitoring points, the contractor will install temporary settlement points to monitor settlements
of the interim cover surface. The temporary settlement points will consist of wooden stakes,
rebar, or an approved equivalent; set a minimum of 12 inches into the interim cover surface.
Settlement data will be collected and analyzed; and the reclamation techniques and schedule will
be adjusted accordingly.
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8.3.2 Monitoring Final Cover Settlement
After placement of final cover material, the contractor will install permanent settlement plates to
monitor settlement of the final cover surface. The settlement plates will consist of a corrosion
resistant steel plate (1/4-inch thick; two-foot square to which a one-inch diameter corrosion
resistant monitor pipe has been welded. The one-inch diameter monitor pipe will be surrounded
by a three-inch diameter guard pipe which will not be attached to the base plate.
The installation will consist of leveling an area on the surface and placing the base plate directly
on the cover soil. A minimum of two feet of initial soil will be placed on the base plate for a
minimum radial distance of five feet from the center pipe.
8.3.3 Monitoring Settlement Points
Settlement monument placement and data collection will be made in accordance with the DRC
approved Settlement Monitoring Plan.
8.3.4 Platform Layer Fill
A layer of 2.5 feet of platform fill will be placed over the tailings surface to form a stable
working platform for subsequent controlled fill placement. This initial lift will be placed by
pushing random fill material or contaminated materials across the tailings in increments, slowly
enough that the underlying tailings are displaced as little as possible. The fill soils shall be
placed in lifts of 12-inch maximum loose thickness to form a uniform subsoil layer for the cover
system. If water addition is required to achieve the required range of moisture contents, the
added water shall be thoroughly mixed into the material prior to compaction.
8.3.5 Highly Compacted Layer
The highly compacted layer shall be placed in lifts with maximum compacted thickness of 6
inches to form a continuous layer with a total minimum compacted layer thickness of 30 inches.
If water addition is required to achieve the required range of moisture contents, the added water
shall be thoroughly mixed into the material prior to compaction.
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8.3.6 Water Storage Layer Fill Placement
Random fill will be placed to a minimum of 42 inches thick, above the highly compacted layer in
12-inch lifts. If oversized material is observed during the excavation of fill material, it will be
removed, as far as practicable, before it is placed in the fill. If water addition is required to
achieve the required range of moisture contents, the added water shall be thoroughly mixed into
the material prior to compaction.
8.3.7 Organic Matter Amendment
The organic matter amendment Biosol® will be applied prior to the placement of topsoil or the
topsoil-gravel mixture. Biosol® will be uniformly spread over the surface of the water storage
layer (frost barrier) and mixed to a depth of 12 in. (30 cm). The proposed application rate may
be adjusted, up or down, based on soil chemical analysis that is conducted prior to placement of
frost barrier fill material (the water storage layer). The soil amendment will be applied prior to
placement of the topsoil and topsoil-rock mixture.
8.3.8 Rock Mulch Placement
The contractor shall provide a method of thoroughly mixing the topsoil and the gravel mixture to
provide the 25% gravel- 75% topsoil mixture (by weight). The mixture shall be prepared prior to
transport to the placement areas. Gradation samples will be collected at the point of placement
(on the topdeck) to verify the mixture’s content. The CQA manager will approve the
contractor’s proposed method of mixing based on the gradation results during initial placement.
The mixture shall be placed in one or more loose lifts to form a uniform layer with a final
thickness of 6 inches on the slope surfaces of the disposal cell (shown on the Drawings). The
gravel-topsoil mixture shall be spread with tracked equipment and compacted using two passes
with rubber-tracked equipment. Low-ground pressure equipment may be necessary to prevent
over-compaction of the mixture. Field density tests will be conducted to monitor and prevent
overcompaction of the material.
The topsoil-gravel erosion control layer will not be amended for organic matter or nutrients to
avoid the stimulation of undesirable weedy species.
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Following placement of the topsoil-gravel erosion protection layer, the area shall be harrowed to
reduce any compaction that may have occurred during placement of the cover and to create an
uneven surface for optimum seedbed conditions.
8.3.9 Topsoil Placement
Topsoil (Section 8.2.7) shall be placed in one or more lifts to form a uniform layer with a final
thickness of 6 inches on the top and side slope surfaces of the disposal cell (shown on the
Drawings). The topsoil shall be spread with tracked equipment and compacted using two passes
with rubber-tracked equipment. Low-ground pressure equipment may be necessary to prevent
over-compaction of the topsoil.
The topsoil layer will not be amended for organic matter or nutrients to avoid the stimulation of
undesirable weedy species.
Following placement of the topsoil layer, the area will be harrowed to reduce any compaction
that may have occurred during placement of the cover and to create an uneven surface for
optimum seedbed conditions.
8.3.10 Rock and Filter Material Placement
The side slopes of the reclaimed cover will be protected by rock surfacing. Riprap, perimeter
apron rock (Section 8.2.5), and erosion protection filter material (Section 8.2.6) shall be placed
in one or more lifts to the depths outlined in the Drawings and using the methods outlined below.
The Drawings show the location of rock protection with the size and thickness requirements for
the various side slopes and aprons.
Filter material and rock shall be handled, loaded, transported, stockpiled, and placed in a manner
that minimizes segregation. Rock and filter material shall be placed in or near its final location
by dumping, then spreading with a small dozer, the bucket of a trackhoe, or other suitable
equipment. Rock and filter material shall be placed and spread in a manner that minimizes
displacement of underlying cover soils, natural soils, or filter material. Each layer of rock and
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filter material shall be track-walked with a small dozer, tamped with the bucket of a trackhoe, or
densified by other approved methods.
Placement of the riprap will avoid accumulation of riprap sizes less than the minimum D50 size
and nesting of the larger sized rock. The riprap layer will be compacted by at least two passes by
a D7 Dozer, tamping with the bucket of a trackhoe, or equivalent methods in order to key the
rock for stability. The completed layer of rock mulch and filter material shall be well-graded in
particle-size distribution and free from pockets of smaller material and free from large voids or
loose areas.
8.4 Performance Standard and Testing
8.4.1 Platform Fill Testing
Compaction of the initial lift will be limited to what the weight of the placement equipment
provides. Placement of fill will be monitored by a qualified individual with the authority to stop
work and reject material being placed.
Testing shall consist of No. 200 sieve wash and particle-size distribution testing (ASTM D422)
and Atterberg limits (ASTM D4318) at a frequency of at least one test per 2,000 cubic yards of
fill placed, or when material characteristics show a significant variation. The lower portion of
the platform fill layer will be compacted to a minimum of 80% maximum dry density for the
material, as determined by the standard Proctor test (ASTM D698) and the top surface (upper 6
inches) of the platform fill will be compacted to 95% maximum dry density for the material, as
determined by the standard Proctor test (ASTM D698). Water contents should be adjusted as
needed to meet the density requirements. If additional water is required to achieve this range of
water contents, the added water shall be thoroughly mixed into the material prior to placement
and/or compaction. The contractor may moisture condition the borrow materials in the borrow
areas and/or during placement.
The frequency of the field density tests will be not less than one test per 1,000 cubic yards of
compacted platform (random fill). A minimum of two tests will be taken for each day that an
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applicable amount of fill is placed in excess of 150 cubic yards. A minimum of one test per lift
and at least one test for every full shift of compaction operations will be taken.
Field density tests shall be compared with Standard Proctor tests (ASTM D698 Method A or C)
on the same material. Standard Proctor tests shall be conducted at a frequency of at least one test
per 5,000 cubic yards of material compacted, or when material characteristics show significant
variation.
Field density testing may be conducted with the sand cone test (ASTM D1556) or a nuclear
density gauge (ASTM D6938, or as modified by the QA Manager). Correlation of nuclear
density gauge results shall be by comparison with results from sand cone test(s) and laboratory
testing for water content(s) using the oven drying method (ASTM D2216) on similar material.
8.4.2 Highly Compacted Layer Testing
Each lift of the highly compacted layer shall be compacted to at least 95 percent of the maximum
dry density for the material, as determined by the standard Proctor test (ASTM D698). Water
contents should be adjusted, as needed, to meet the density requirements.
Material specifications for the random fill material shall be confirmed by gradation testing
conducted by approved personnel. Testing shall consist of No. 200 sieve wash and particle-size
distribution testing (ASTM D422) and Atterberg limits (ASTM D4318) at a frequency of at least
one test per 2,000 cubic yards of fill placed, or when material characteristics show a significant
variation.
Checking of compaction shall consist of a minimum of one field density test per 500 cubic yards
of material compacted. A minimum of two tests shall be taken for each day that an applicable
amount of fill is placed in excess of 150 cubic yards. A minimum of one test per lift and at least
one test for every full shift of compaction operations will be taken.
Field density tests shall be compared with Standard Proctor tests (ASTM D698 Method A or C)
on the same material. Standard Proctor tests shall be conducted at a frequency of at least one test
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per 2,500 cubic yards of material compacted, or when material characteristics show significant
variation.
Field density testing may be conducted with the sand cone test (ASTM D1556) or a nuclear
density gauge (ASTM D6938, or as modified by the QA Manager). Correlation of nuclear
density gauge results shall be by comparison with results from sand cone test(s) and laboratory
testing for water content(s) using the oven drying method (ASTM D2216) on similar material.
8.4.3 Water Storage Layer Fill Material Testing
Material specifications for the random fill for water storage layer shall be confirmed by gradation
testing conducted by approved personnel. Testing shall consist of No. 200 sieve wash and
particle-size distribution testing (ASTM D422) and Atterberg limits (ASTM D4318) at a
frequency of at least one test per 2,000 cubic yards of fill placed, or when material characteristics
show a significant variation. Cover material compaction will be verified by the maximum lift
thickness outlined in Section 8.3.6.
Each lift of this upper fill material layer shall be compacted to at least 85 percent of the
maximum dry density for the material, as determined by the standard Proctor test (ASTM D698).
Water contents should be adjusted, as needed, to meet the density requirements.
The frequency of the field density and moisture tests will be not less than one test per 1,000
cubic yards of compacted fill. A minimum of two tests will be taken for each day that an
applicable amount of fill is placed in excess of 150 cubic yards. A minimum of one test per lift
and at least one test for every full shift of compaction operations will be taken.
Field density tests shall be compared with Standard Proctor tests (ASTM D698 Method A or C)
on the same material. Standard Proctor tests shall be conducted at a frequency of at least one test
per 5,000 cubic yards of material compacted, or when material characteristics show significant
variation.
Field density testing may be conducted with the sand cone test (ASTM D1556) or a nuclear
density gauge (ASTM D6938, or as modified by the QA Manager). Correlation of nuclear
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density gauge results shall be by comparison with results from sand cone test(s) and laboratory
testing for water content(s) using the oven drying method (ASTM D2216) on similar material.
8.4.4 Topsoil Testing
Material specifications for the topsoil material shall be confirmed by Atterberg limits testing
(ASTM D4318) on samples of the topsoil, once for each 1,000 cubic yards of total topsoil
material placed (including the quantity of topsoil added to the rock mulch mixture).
The topsoil shall be compacted to between 80 and 85 percent of the maximum dry density for the
material, as determined by the standard Proctor test. During placement, the material shall be
within the optimum moisture content and 3 percent below the optimum moisture content for the
material, as determined by the standard Proctor test.
Checking of compaction of the topsoil shall consist of a minimum of one field density test per
500 cubic yards of material placed. A minimum of two tests shall be taken for each day that an
applicable amount of fill is placed in excess of 150 cubic yards. A minimum of one test per lift
and at least one test for every full shift of placement operations will be taken.
Field density tests shall be compared with Standard Proctor tests (ASTM D698 Method A or C)
on the same material. Standard Proctor tests shall be conducted at a frequency of at least one test
per 2,500 cubic yards of material placed, or when material characteristics show significant
variation.
Field density testing may be conducted with the sand cone test (ASTM D1556) or a nuclear
density gauge (ASTM D6938, or as modified by the QA Manager). Correlation of nuclear
density gauge results shall be by comparison with results from sand cone test(s) and laboratory
testing for water content(s) using the oven drying method (ASTM D2216) on similar material.
8.4.5 Rock Mulch Testing
The maximum particle size for the rock used for rock mulch material shall be confirmed by
gradation testing prior to mixing with the topsoil, to determine the maximum particle size.
Testing shall consist of particle-size distribution testing (ASTM D422) at a frequency of at least
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one test per 2,000 cubic yards of rock delivered to the site, or when rock characteristics show a
significant variation.
The gradation specifications for the rock mulch material (topsoil-gravel mixture) (Specification
Section 8.2.4) shall be confirmed by gradation testing, on samples collected from the point of
placement (on the topdeck). Testing shall consist of particle-size distribution testing (ASTM
D422) at a frequency of at least one test per 2,000 cubic yards of mixture placed, or when the
characteristics of the mixture show a significant variation. The QA Manager may choose to
conduct to increase the frequency of testing at the beginning of placement to evaluate the mixing
method proposed by the contractor.
Rock mulch thickness will be controlled through the establishment of grade stakes placed on a
200 x 200 foot grid on the top of the cells and by a 100 x 100 foot grid on the cell slopes.
Physical checks of rock mulch depth will be accomplished through the use of hand dug test pits
at the center of each grid in addition to monitoring the depth indicated on the grade stakes.
The rock mulch mixture shall be compacted to between 80 and 85 percent of the maximum dry
density for the material, as determined by the standard Proctor test. During placement, the
material shall be within the optimum moisture content and 3 percent below the optimum
moisture content for the material, as determined by the standard Proctor test.
Checking of compaction of the rock mulch mixture shall consist of a minimum of one field
density test per 500 cubic yards of material placed. A minimum of two tests shall be taken for
each day that an applicable amount of fill is placed in excess of 150 cubic yards. A minimum of
one test per lift and at least one test for every full shift of placement operations will be taken.
Field density tests shall be compared with Standard Proctor tests (ASTM D698 Method A or C)
on the same material. Rock corrections (ASTM D4718) for oversize particles may be required
for the mixture depending on the gradation of the gravel material selected. Standard Proctor tests
shall be conducted at a frequency of at least one test per 2,500 cubic yards of material placed, or
when material characteristics show significant variation.
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Field density testing may be conducted with the sand cone test (ASTM D1556) or a nuclear
density gauge (ASTM D6938, or as modified by the QA Manager). Correlation of nuclear
density gauge results shall be by comparison with results from sand cone test(s) and laboratory
testing for water content(s) using the oven drying method (ASTM D2216) on similar material.
The durability of the rock shall be verified by durability tests outlined in Specification Section
8.4.8.
8.4.6 Erosion Protection and Perimeter Apron Rock Testing
Material specifications for the perimeter apron rock shall be confirmed by gradation testing
conducted by approved personnel. Testing shall consist of particle-size distribution testing
(ASTM D422) at a frequency of at least one test per 2,000 cubic yards of rock delivered to the
site, or when rock characteristics show a significant variation.
Rock layer thickness will be controlled through the establishment of grade stakes placed on a
200 x 200 foot grid on the top of the cells and by a 100 x 100 foot grid on the cell slopes.
Physical checks of riprap depth will be accomplished through the use of hand dug test pits at the
center of each grid in addition to monitoring the depth indicated on the grade stakes.
The durability of the rock shall be verified by durability tests outlined in Specification Section
8.4.8.
8.4.7 Erosion Protection Filter Testing
Material specifications for erosion protection filter material (Section 8.2.6) shall be confirmed by
gradation testing conducted by approved personnel. Testing shall consist of No. 200 sieve wash
and maximum particle size testing (ASTM D422) at a frequency of at least one test per 2,000
cubic yards of fill placed, or when material characteristics show a significant variation.
Filter layer thickness will be established during construction with grade stakes placed on a grid
or centerline and offset pattern and layer thickness marks on each grade stake. The minimum
thickness of the layer will be verified by spot checking of layer thickness by hand excavation in
selected locations.
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8.4.8 Rock Durability Testing
For riprap materials, each load of material will be visually checked against standard piles for
gradation prior to transport to the tailings piles. Prior to delivery of any riprap materials to the
site, rock durability tests will be performed for each gradation to be used. Test series for riprap
durability will include specific gravity, absorption, sodium soundness and LA abrasion. During
construction, additional test series and gradations will be performed for each type of riprap when
approximately one-third (1/3) and two-thirds (2/3) of the total volume of each type have been
produced or delivered. For any type of riprap where the volume is greater than 30,000 cubic
yards, a test series and gradations will be performed for each additional 10,000 cubic yards of
riprap produced or delivered.
8.5 Surface Slopes and Grades
The final cover surface shall have maximum side slopes of 5:1 and a top surface sloping in the
direction and grade shown on the Drawings. The side slopes and top surface shall be free from
abrupt changes in grade or areas of runoff concentration. The perimeter apron at the toe of the
side slopes shall have a minimum width of 20 feet from the toe of the side slopes and slope away
from the toe of the side slopes (as shown on the Drawings).
8.6 Grading Tolerances
The completed cover surface shall be constructed to within 1.0 foot (horizontally) of the lines as
designed, and within 0.1 foot (vertically) of the elevations as designed. The final surface of the
subsoil zone shall be smoothed to avoid abrupt changes in surface grade. The layer thicknesses
shall meet the required minimum thicknesses.
The completed riprap shall be placed to within 5.0 foot (horizontally) of the layout as designed,
and within 0.5 foot (vertically) of the elevations as designed. The rock layer thicknesses shall
meet the minimum requirements.
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9 REVEGETATION
9.1 General
Following topsoil placement, the cover surface and other areas disturbed during reclamation
work will be revegetated. This section outlines the requirements for vegetation establishment
where required. This section may be revised as necessary based on field requirements and soil
nutrient analyses at the time of revegetation.
9.2 Materials Description
The soil amendments, seed mixture, and erosion control materials for revegetation are outlined
below. Submittals for each of the following products shall be provided to the Owner for approval
prior to use of such products.
9.2.1 Soil Amendments
The proposed application rate may be adjusted up or down based on soil chemical analysis that is
conducted prior to placement of the water storage layer.
Biosol® shall be added at a rate 1.5 tons/acre and uniformly spread over the surface of the water
storage layer and mixed to a depth of 30 cm. This treatment will be applied after the water
storage layer is in-place and before placement of the topsoil-gravel erosion protection layer.
9.2.2 Seed Mix
Species selection for the seed mixture was based on native vegetation found at the site area as
well as soil and climatic conditions of the area. Changes to the seed mixture will be as approved
by the Owner. The following seed mixture shall be used on all seeded areas.
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Table 9.1 – Seed Mixture
Scientific Name Common Name
Native/
Introduced
Seeding
Rate
(# PLS/ft2) †
Seeding
Rate (lbs
PLS/acre)†
Grasses
Pascopyrum smithii Western wheatgrass Native 6.0 3.0
Pseudoroegneria
spicata
Bluebunch
wheatgrass
Native 8.0 3.0
Elymus trachycaulus Slender wheatgrass Native 5.0 2.0
Elymus lanceolatus Streambank
wheatgrass
Native 5.5 2.0
Elymus elymoides Squirreltail Native 7.0 2.0
Thinopyrum
intermedium
Pubescent
wheatgrass
Introduced‡ 1.5 1.0
Achnatherum
hymenoides
Indian ricegrass Native 8.0 4.0
Poa secunda Sandberg bluegrass Native 9.0 0.5
Festuca ovina Sheep fescue Native 9.0 1.0
Bouteloua gracilis Blue grama Native 13.0 1.0
Forbs
Achillea millefolium Common yarrow Native 23.0 0.5
Artemisia ludoviciana White sage Native 23.0 0.5
Total 118.0 21.0
†Seeding rate is for broadcast seed and presented as number of pure live seeds per ft2 & pounds of pure live seed
per acre. ‡Introduced refers to species that have been ‘introduced’ from another geographic region, typically outside of N.
America.
Seed shall be purchased as pounds of pure live seed and will be certified by the Utah State
Department of Agriculture and Food Certification that the seed is correctly identified and
genetically pure. Once the seed is obtained, seed labels will be checked to determine the percent
PLS and the date that the seed was tested for percent purity and percent germination. If the test
date is greater than 6 months old, the seed must be tested again before being accepted.
9.2.3 Erosion Control Materials
Wood fiber mulch will consist of specially prepared wood fibers and will not be produced from
recycled material such as sawdust, paper, cardboard, or residue from pulp and paper plants. The
fibers will be dyed an appropriate color, with non-toxic, water-soluble dye to facilitate visual
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metering during application. Wood-fiber mulch will be supplied in packages and each package
will be marked by the manufacturer to show the air-dry weight.
A tackifier will be used with the wood-fiber mulch to improve adhesion. The tackifier will be a
biodegradable organic formulation processed specifically for the adhesive binding of mulch. In
addition, the tackifier will uniformly disperse when mixed with water and will not be detrimental
to the homogeneous properties of the mulch slurry.
9.3 Work Description
Revegetation efforts shall be directed at all reclaimed and disturbed areas. The goal of the
revegetation plan is to ensure that a self-sustaining vegetative community is established.
9.4 Soil Amendment Application
Following the final placement and grading of the frost barrier layer, amendments will be applied
as necessary (Section 9.2.1). Organic amendments will be applied based on the nature of organic
material used. Inorganic sources of nitrogen, phosphorus, and potassium will be applied to the
soil by broadcast spreader. Rates of application will be determined from soil analyses.
9.5 Growth Zone Preparation
A favorable seedbed shall be prepared on the topsoil layer or topsoil-rock mixture, prior to
seeding operations. The soil should be loose and friable so as to maximize contact with the seed.
The soil will be tilled, following site contours with a disc or harrow (or similar approved
equipment) to a maximum depth of 6 inches. The depth of valleys and the height of ridges
caused by the final tillage operations are not to exceed 3 inches.
9.6 Seed Application
Seeding will follow the application of soil amendments and seedbed preparation, by broadcast
spreading method. This procedure will use a centrifugal type broadcaster, also called an end gate
seeder. The broadcasters will have a minimum effective spreading width of 20 feet. Seed will
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be applied in two separate passes. One-half of the seed will be spread in one direction and the
other half of seed will be spread in a perpendicular direction. This will ensure that seed
distribution across the site is highly uniform and also provide the opportunity to adjust the
seeding rate if the specified rate is not being achieved. Seeding will not occur if wind speeds
exceed 10 mph.
Immediately following seeding, the area will be lightly harrowed to provide seed coverage and to
maximize seed-soil contact. Broadcast seed shall be harrowed into the soil to a depth of 0.25 to
0.75 inches.
Seeding will take place as soon as practical after the cover system is in place. Successful seeding
in southeastern Utah can occur either in late fall (e.g. October) as a dormant seeding, with
germination and establishment occurring the following spring or can be conducted in June, prior
to the summer monsoon season. The timing for seeding will be dependent upon the construction
schedule for the cover system.
9.7 Erosion Control Material Application
Mulch will be applied immediately following seeding. A weed-free, wood-fiber mulch shall be
applied to the seeded area at a minimum rate of 1.0 ton/acre. The wood-fiber mulch will be
applied by means of hydraulic equipment that utilizes water as the carrying agent. A continuous
agitator action, that keeps the mulching material and approved additives in uniform suspension,
will be maintained throughout the distribution cycle.
The pump pressure will be capable of maintaining a continuous non-fluctuating stream of slurry.
The slurry distribution lines will be large enough to prevent stoppage and the discharge line will
be equipped with a set of hydraulic spray nozzles that will provide an even distribution of the
mulch slurry to the seedbed. Mulching will not be done in the presence of free surface water
resulting from rains, melting snow, or other causes.
Tackifier may be added either during the manufacturing of the mulch or incorporated during
mulch application.
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9.8 Performance Standard and Testing
The following section describes performance-based criteria for successful revegetation.
9.8.1 Seeding Rates
Prior to seeding, a known area will be covered with a tarp and seed will be distributed using the
broadcaster and simulating conditions that would exist under actual seeding conditions. Seed
will then be collected and weighed to determine actual seeding rate in terms of pounds per acre.
This process will be repeated until the specified seeding rate is obtained.
During the seeding process, the seeding rate will be verified at least once by comparing pounds
of seed applied to the size of the area seeded.
9.8.2 Erosion Control
The cover shall be inspected two times per year for eroded areas. Any area that has experienced
erosion shall be backfilled and reseeded. Erosion control materials shall also be reapplied over
reseeded areas.
9.8.3 Weed Control
The cover shall be inspected for the presence of weedy species at least two times per year (once
in late spring, and once in mid-summer). Weed species should be identified and the approximate
coverage should be noted. Spot-spraying of weeds may be necessary to control unwanted
species.
9.8.4 Vegetation Establishment Performance
Total vegetative cover sampling shall be performed at a future date to ascertain vegetation
establishment success. The revegetation effort shall be deemed successful if the total vegetation
cover on the mill tailings cover is at least 70 percent of the total cover of a nearby background
reference area for two consecutive years. Areas that do not meet this performance criterion shall
be reseeded.
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10 REFERENCES
American Society for Testing and Materials (ASTM), 2011. Annual Book of ASTM Standards:
Section 4, Construction; Volume 4.08, Soil and Rock(I), D420 to D5876.
Denison Mines (USA) Corp. 2009. Reclamation Plan White Mesa mill, Blanding Utah, Rev. 4.
November.
Goldsmith, W., Silva, M., and Fischenich, C. 2001. Determining Optimal Degree of Soil
Compaction for Balancing Mechanical Stability and Plant Growth Capacity, Report
ERDC-TN-EMRRP-SR-26., U.S. Army Engineer Research and Development Center,
Vicksburg, MS. May 2001, 9 pp.
Gray, D. H. 2002. “Optimizing Soil Compaction and Other Strategies,” Erosion Control. Volume
9, No. 5, September-October 2002. URL: http://www.erosioncontrol.com/september-
october-2002/optimizing-soil-compaction.aspx.
Johnson, T.L., 1999. “Design of Protective Covers.” U.S. Nuclear Regulatory Commission
(NRC), NUREG 2615 Draft for Comment. February.
Johnson, T.L., 2002. “Design of Erosion Protection for Long-Term Stabilization.” U.S. Nuclear
Regulatory Commission (NRC), NUREG 1623, Final Report. September.
Nuclear Regulatory Commission (NRC), 1989. “Staff Technical Position on Testing and
Inspection Plans During Construction of DOE’s Remedial Action at Inactive Uranium
mill Tailings Sites.” Revision 2. January.
Nuclear Regulatory Commission (NRC), 1990. “Final Staff Technical Position, Design of
Erosion Protective Covers for Stabilization of Uranium mill Tailings Sites.” January.