DRC-2011-007726 - 0901a0688029ac53

DENISO
MINES
Denison ^es (US^Ccyfp.
105017th Street, Suite 950
Denver, CO 80265
USA
Tel: [phone]
Fax:[phone]
www.denisonmines.com
December 28, 2011
VIA E-MAIL AND OVERNIGHT DELIVERY
Mr. Rusty Lundberg
Utah Department of Environmental Quality
195 North 1950 West
P.O. Box 144850
Salt Lake City, UT 84114-4850
Re: Radioactive Materials License DRC-04, Reclamation Plan Revision 4.0
Response to Interrogatories 1 and 1A
Dear Mr. Lundberg:
This letter transmits Denison Mines (USA) Corp.'s ("Denison's") Responses to Supplemental Interrogatories
Round #1 and 1A regarding White Mesa Mill Reclamation Plan Revision 4.0, November 2009.
Please contact me if you have any questions or require any further information.
Yours very truly,
DENISON MINES (USA) CORP.
Jo Ann Tischler
Director, Compliance and Permitting
cc: David C. Frydenlund
Harold R. Roberts
David E. Turk
K. Weinel
Central files
Y:\Reclamatlon Plan\Rec Plan Interroatory response 12.28.11\12.28.11 Rec Plan Interrog respo9nsatmsmtl.doc
DENISON MINES (USA) CORP.
RESPONSES TO SUPPLEMENTAL
INTERROGATORIES - ROUND lA FOR
RECLAMATION PLAN, REVISION 4.0,
NOVEMBER 2009;
DECEMBER 2011
INTERROGATORY WHITE MESA RECPLAN 02/01 A: 10CFR40 APPENDIX A, CRITERION 1:
PERMANENT ISOLATION WITHOUT ONGOING MAINTENANCE
REGULATORY BASIS:
UAC R313-24-4 invokes the followins requirement from 10CFR40 Appendix A, Criterion 1: "The general
goal or broad objective in siting and design decisions is permanent isolation of tailings and associated
contaminants by minimizing disturbance and dispersion by natural forces, and to do so without ongoing
maintenance. For practical reasons, specific siting decisions and design standards must involve finite
times (e.g., the longevity design standard in Criterion 6). The following site features which will contribute
to such a goal or objective must be considered in selecting among altemative tailings disposal sites or
judging the adequacy of existing tailings sites:
• Remoteness from populated areas;
• Hydrologic and other natural conditions as they contribute to continued immobilization and
isolation of contaminants from ground-water sources; and
• Potential for minimizing erosion, disturbance, and dispersion by natural forces over the long
term.
The site selection process must be an optimization to the maximum extent reasonably achievable in terms
of these features.
In the selection of disposal sites, primary emphasis must be given to isolation of tailings or wastes, a
matter having long-term impacts, as opposed to consideration only of short-term convenience or benefits,
such as minimization of transportation or land acquisition costs. While isolation of tailings will be a
function of both site and engineering design, overriding consideration must be given to siting features
given the long-term nature of the tailings hazards.
Tailings should be disposed of in a manner that no active maintenance is required to preserve conditions
of the site."
INTERROGATORY STATEMENT:
1. Refer to Sections 3.2.2, 3.3, Section 5 of Attachment A, Figures A-5.1-1 through A-5.1-3, and
Table A-5.3.2.1-1 of the Rev 4.0 Reclamation Plan, and MWH 2010: In addition to the information
requested in Round 1 Interrogatory White Mesa RecPlan 02/01 (as it remains applicable to the
proposal alternative cover design), please provide the following information for the proposed
alternative tailings cell cover design (MWH 2010):
1. Provide additional information on the specific characteristics of soils (sandy clayey silt
materials) proposed for use in constructing the proposed altemative cover design to demonstrate
that the soil will have adequate properties (e.g., favorable water relations, appropriate nutrient
capacity and Sodium Absorption Ratio, etc..) that are compatible with the vegetation community
that is proposed for establishment in the final cover. Provide information demonstrating that the
soils would be likely to achieve the goal of establishing "primarily grasses " (MWH 2010) on the
cover in a manner which will allow the seeded/established grasses to competitively preclude
long-term invasion ofthe vegetated surfaces by deeper-rooted trees and shrubs.
Response 1(1):
Additional information on soil (as related to plant growth) and vegetation that would be
used as an integral part of the proposed evapotranspiration (ET) cover for reclamation of
the tailings cells is provided in Appendix D of the Updated Tailings Cover Design Report
(submitted to the Executive Secretary as Appendix D of the Denison 2011 Reclamation
interrogatory 02/01A: 10CFR40 Appendix A, Criterion 1: Pemianent Isolation without Ongoing IVlaintenance Page 1 of 25
Plan for the White Mesa Mill). Information on soils and vegetation discussed in
Appendix D of the Updated Tailings Cover Design Report include:
• Results of physical and chemical analysis of soils that are proposed for the cover
system;
• Ranges of soil characteristics from literature that are considered to be adequate
for sustained plant growth for a grassland community;
• List of soil properties for the proposed cover that appear to be deficient for plant
growth and recommendations for appropriate amendments;
• Recommendations for the proposed seed mixture; and
• Discussion on competition of the seeded species with weeds or woody species.
Describe assumptions that have been made, with supporting rationale, with respect to the degree
to which any more shallow-rooted plants (e.g., shallow-rooting trees or shrubs) could colonize
the proposed alternative cover during the required design life of the cover (200-1,000 years) and
that might be prone to future tip-up/blow-over, resulting in physical damage to the cover system
over the long term, unless they were removed through an active maintenance program.
Response 1(2):
See Response 1(1). Discussion regarding competition of the seeded species with
woody species is provided in Appendix D of the Updated Tailings Cover Design Report.
The potential for establishment of shallow rooted woody plants that would be prone to tip
up/blow over, thus causing physical damage to the cover system over the long term is
highly unlikely, even under a no-active maintenance scenario.
Evaluate and provide information to demonstrate the capability of the altemative cover design
for preventing possible future penetration of the tailings by plants or burrowing animals under
the no-active maintenance scenario. Please provide the following as part of this evaluation:
a. Information on the potential for future deep-rooted plants and deep-burrowing animals to
occur at/frequent the site or site vicinity, including any occurrences that could result from
future climate changes occurring within the required performance period for the cover (200-
1,000 years).
b. Information on the possible need for including a cobble layer, capillary break layer, and/or
later drainage layer in the cover system to mitigate/prevent penetration of the cover
throughout the required performance period (200-1,000 years) by burrowing animals or root
growth, under the no-active maintenance scenario.
Response 1(3):
See Response 1(1) and 1(2). Discussion regarding competition ofthe seeded species
with woody species, as well as an evaluation of biointrusion is provided in Appendix D of
the Updated Tailings Cover Design Report. The potential for deep-rooted plants and
deep-burrowing animals to occur at or frequent the site is extremely low.
The potential occurrence of deep-rooted plants or deep-burrowing animals as a result of
future climate change is discussed in Appendix D of the Updated Tailings Cover Design
Report. The occurrence of a warmer climate in southeastern Utah, with an increase in
atmospheric CO2 that might exist during the required performance period (200 - 1,000
years) is not expected to substantially change the established plant community,
regardless of either a corresponding decrease or increase in precipitation. The
Inten-ogatory 02/01A: 10CFR40 Appendix A, Criterion 1: Permanent Isolation without Ongoing Maintenance Page 2 of 25
community should remain grass dominated with some shift in dominance among warm
and cool season species. In addition, it is not expected that a change in climate within
the required performance period would lead to a change in small mammal presence or in
burrowing activity.
As discussed above, the expectation is for minimal change in plant and animal
communities throughout the required performance period. Therefore, there is no
recognizable need to incorporate biointrusion layer into the cover system.
Refer to Sections 3.2.2, 3.3, Section 5 of Attachment A, Figures A-5.1-1 through A-5.1-3, and
Table A-5.3.2.1-1 of the Rev 4.0 Reclamation Plan, and MWH 2010: In addition to the information
requested in Interrogatory White Mesa RecPlan 02/01 (as it remains applicable to the proposal
alternative cover design), please provide the following information for the proposed alternative
tailings cell cover design (MWH 2010):
• Provide information regarding the need for incorporating a filter layer at one or more of the
interface(s) between the sideslope cover components and the components of the topdeck
portion ofthe proposed alternative cover design. Evaluate filter requirements for limiting the
possible movement offine soil particles derived from intemal erosion of the proposed
topdeck gravel/topsoil unit and loosely compacted topdeck soil layers into any filter and
sideslope riprap erosion protection layer that would be incorporated into the cover. Provide
filter stability criteria and supporting calculations utilizing applicable filter design criteria
(e.g., as described in NUREG-1623), guidance contained in NUREG/CR-4620 (Nelson, et al.
1986), and other applicable guidance documents (e.g., USDA 1994). Altematively, provide
detailed information that would clearly justify why such filter layer would not be required.
Response 2:
An evaluation of the need for a filter layer between the top cover layer and the erosion
protection layer on the sideslopes, as well as below the rock aprons is provided in
Appendix G of the Updated Tailings Cover Design Report. A filter/bedding layer is
recommended beneath the erosion protection layer on the sideslopes. A filter/bedding
layer is not required beneath the riprap of the rock aprons.
BASIS FOR INTERROG A TORY:
As discussed in Round 1 Interrogatory White Mesa RecPlan 02/01, maximum burrowing depths for
animals at or near the site should be defined and justification provided as to how the proposed altemative
cover design will prevent potential long-term damage/disruption of the buried tailings by burrowing
animals and/or deep plant root penetration. Different published references indicate that Big Sagebrush in
the westem U.S. can exhibit typical average rooting depths between about 114 and 250 cm [between
about 3.7 and 8ft] (e.g., see Waugh, et al. 1994; Foxx, et all984; Klepper, et al. 1985, Reynolds 1990b);
however, at least one reference suggests that root depths for Big Sagebrush could be much deeper-
possibly extending to up to 914 cm [30ft] (Foxx, et all984).
The proposed alternative cover design (MWH 2010) does not contain a capillary break layer, lateral
drainage layer, or cobble rock layer. Inclusion of a layer of this type (with any required filter layers also
provided to prevent migration offines into the voids of this layer) could help provide a barrier to prevent
deep root penetration within the cover. For example, in certain circumstances, established plant species
could undergo agronomic stress (as a result of unfavorable water relations and/or insufficient nutrient
Inten-ogatory 02/01 A: 10CFR40 Appendix A, Criterion 1: Permanent Isolation wittiout Ongoing Maintenance Page 3 of 25
capacity in the cover soils during a dry weather period). Certain plants could likely extend their roots
seeking water and nutrients in response to such stresses (e.g., see DOE 1989, Section 4.3.4) - see also
Interrogatory RecPlan 09/OlA: UAC R313-25-7; UAC R313-25-8; UAC R317-6-1 (6)6.1: Infiltration
through the Final Cover, below. Additional information needs to be provided that demonstrates the
ability of the proposed altemative cover materials/system to provide and maintain the appropriate
nutrient capacity and favorable water relations required to promote an uninterrupted cover ofthe
intended/preferred grasses over the cover system throughout the required design life of the embankment
(200-1,000 years). The evaluation should take into consideration the future climate, soil properties,
pedogenesis, and rooting characteristics of the desired plants on the cover (DOE 1989).
Although compacted soil layers in final cover system may offer some protection against root penetration,
plants vary greatly in their ability to penetrate compacted soils (Waugh and Richardson 1997). At arid
and semi-arid sites, root densities can be higher in buried clayey-type soils and plant roots may
concentrate in and extract water from buried clayey layers, causing some seasonal desiccation
(Hakonson 1986 and Reynolds 1990a,b). Based on these considerations, there is likely to be uncertainty
as to the degree to which shallower-rooted trees or shrubs or deeper-rooted plants (e.g.. Big Sagebrush)
might eventually become established in the cover system during the required design life ofthe
embankment, especially during the future no-active maintenance period. The potential therefore exists for
some degree ofpenetration of the cover system by the roots of deeper-rooted plants following final cover
construction. The range ofpotential future plant development and animal burrowing conditions for the
final cover environment needs to be adequately defined for use as input in subsequent performance model
assessments.
Inclusion of a rocky layer within the final cover would also provide a deterrent against future burrowing
by animals as the animals would not attempt to move into a rocky, unfavorable layer in lieu ofa more
favorable soil medium.
The need for incorporating a filter layer included at critical interfaces between the sideslope cover
components and the components of the topdeck portion of the proposed altemative cover design. For
example, a filter layer should be included to limit the possible movement of fine soil particles derived
from intemal erosion of the proposed topdeck gravel/topsoil and loosely compacted topdeck soil layers
into any filter and sideslope riprap erosion protection layer included in the final cover design. Without
inclusion of an appropriate filter in such instances, piping offines from the top deck portion ofthe cover
system could occur if seepage gradients or pressures are high enough to initiate erosive discharge
velocities at the basefiow. (USDA 1994).
REFERENCES:
Foxx, T.S., G.D. Tiemey, and J.M. Williams 1984. Rooting Depths of Plants Relative to Biological and
Environmental Factors, Los Alamos Report LA-10254-MS, November 1984.
Hakonson, T.E. 1986. Evaluation of Geologic Materials to Limit Biological Intrusion into Low-Level
Radioactive Waste Disposal Sites. LA-10286-MS. Los Alamos National Laboratory, Los Alamos,
New Mexico.
Klepper, E. L., K. A. Gano, and L. L. Cadwell 1985. Rooting Depth and Distributions of Deep-Rooted
Plants in the 200 Area Control Zone of the Hanford Site, PNL-5247, Battelle Pacific Northwest
Laboratory, Richland, Washington.
MWH 2010. "Proposed Preliminary Altemative Cover Design for White Mesa Tailings Cells". Letter
from MHWto Harold Roberts of Denison Mines (USA) Corp. dated October 6, 2010.
Interrogatory 02/01A: 10CFR40 Appendix A, Criterion 1: Pemianent Isolation without Ongoing Maintenance Page 4 of 25
NRC (U.S. Nuclear Regulatory Commission) 2003. Standard Review Plan for the Review of a
Reclamation Plan for Mill Tailings Sites under Title II of the Uranium Mill Tailings Radiation
Control Act of1978. Washington, D.C, June 2003.
Reynolds, TD. 1990a. Effectiveness of Three Natural Biobarriers in Reducing Root Intrusion by Four
Semi-Arid Plant Species. Health Physics, Vol 59, pp. 849-852.
Reynolds, T. D. 1990b. "Root Mass and Vertical Root Distribution of Five Semiarid Plant Species. "
Health Physics, Vol 58, No. 2, pp. 191-197.
U.S. Department of Agriculture (USDA) 1994. "Chapter 26, Gradation Design of Sand and Gravel
Filters ". Part 633 - National Engineering Handbook, Washington, D.C. October 1994, 47pp.
U.S. Departmentof Energy (DOE) 1989. Technical Approach Document, Revision 2. UMTRA-DOE/AL
050425.0002, Albuquerque, New Mexico. December 1989.
Waugh, W. J.,JC. Charters, G. V. Last, B. N Bjomstad, S. O. Link, C. R. Hunter 1994. Barrier Analogs:
Long-Term Performance Issues, Preliminary Studies, and Recommendations, PNL-9004, Pacific
Northwest Laboratories, Richland, Washington.
Waugh, W.J., and Richardson, G.N., 1997. "Ecology, Design, and Long-Term Performance of Surface
Barriers: Applications at Uranium Mill Tailings Sites. " Barrier Technologies for Environmental
Management, National Academy Press, 1997.
Inten-ogatory 02/01 A: 10CFR40 Appendix A, Criterion 1: Pemnanent Isolation without Ongoing Maintenance Page 5 of 25
INTERROGATORY WHITE MESA RECPLAN 03/OlA: 10CFR4G, APPENDIX A, CRITERION
4: LOCATION AND DESIGN RQUIREMENTS
REGULA TORY BASIS:
UAC R313-24-4 invokes the following requirement from 10CFR40. Appendix A. Criterion 4: "The following
site and design criteria must be adhered to whether tailings or wastes are disposed of above or below
grade.
(a) Upstream rainfall catchment areas must be minimized to decrease erosion potential and the size ofthe
floods which could erode or wash out sections of the tailings disposal area.
(b) Topographic features should provide good wind protection.
(c) Embankment and cover slopes must be relatively flat after flnal stabilization to minimize erosion
potential and to provide conservative factors of safety assuring long-term stability. The broad objective
should be to contour final slopes to grades which are as close as possible to those which would be
provided if tailings were disposed of below grade; this could, for example, lead to slopes of about 10
horizontal to 1 vertical (10h:lv) or less steep. In general, slopes should not be steeper than about 5h:lv.
Where steeper slopes are proposed, reasons why a slope less steep than 5h:lv would be impracticable
should be provided, and compensating factors and conditions which make such slopes acceptable should
be identified.
(d) A full self-sustaining vegetative cover must be established or rock cover employed to reduce wind and
water erosion to negligible levels.
Where a full vegetative cover is not likely to be self-sustaining due to climatic or other conditions, such as
in semi-arid and arid regions, rock cover must be employed on slopes of the impoundment system. The
Executive Secretary will consider relaxing this requirement for extremely gentle slopes such as those
which may exist on the top of the pile.
The following factors must be considered in establishing the final rock cover design to avoid
displacement of rock particles by human and animal traffic or by natural process, and to preclude
undercutting and piping:
• Shape, size, composition, and gradation of rock particles (excepting bedding material
average particles size must be at least cobble size or greater);
• Rock cover thickness and zoning of particles by size; and
• Steepness of underlying slopes.
Individual rock fragments must be dense, sound, and resistant to abrasion, and must be free from cracks,
seams, and other defects that would tend to unduly increase their destmction by water and frost actions.
Weak, friable, or laminated aggregate may not be used.
Rock covering of slopes may be unnecessary where top covers are very thick (or less); bulk cover
materials have inherently favorable erosion resistance characteristics; and, there is negligible drainage
catchment area upstream of the pile and good wind protection as described in points (a) and (b) of this
criterion.
Furthermore, all impoundment surfaces must be contoured to avoid areas of concentrated surface runoff
or abrupt or sharp changes in slope gradient. In addition to rock cover on slopes, areas toward which
surface runoff might be directed must be well protected with substantial rock cover (rip rap). In addition
to providing for stability of the impoundment system itself overall stability, erosion potential, and
interrogatory 03/01 A: 10CFR40 Appendix A, Criterion 4: Location and Design Requirements Page 6 of 25
geomorphology of surrounding terrain must be evaluated to assure that there are not ongoing or
potential processes, such as gully erosion, which would lead to impoundment instability.
(e) The impoundment may not be located near a capable fault that could cause a maximum credible
earthquake larger than that which the impoundment could reasonably be expected to withstand. As used
in this criterion, the term "capable fault" has the same meaning as defined in section Ill(g) of Appendix A
of 10 CFR Part 100. The term "maximum credible earthquake" means that earthquake which would cause
the maximum vibratory ground motion based upon an evaluation of earthquake potential considering the
regional and local geology and seismology and specific characteristics of local subsurface material
(f) The impoundment, where feasible, should be designed to incorporate features which will promote
deposition. For example, design features which promote deposition of sediment suspended in any runoff
which fiows into the impoundment area might be utilized; the object of such a design feature would be to
enhance the thickness of cover over time. "
INTERROGATORY STATEMENT:
1. Refer to Sections 3.2.1, 3.2.2, 3.3, Section 5.1 of Attachment A, Figures A-5.1-1 through A-5.1-3,
and Table A-5.3.2.1-1 of the Rev 4.0 Reclamation Plan, and MWH 2010: In addition to the
information requested in Round 1 Interrogatory White Mesa RecPlan 03/01 (as it remains applicable
to the proposal alternative cover design), please provide and justify the adequacy of the following
information for the proposed alternative tailings cell cover design:
a. Provide procedures that will be used to produce and install the proposed gravel/topsoil
admixture layer on the topdeck portion of the proposed alternative cover system. Include
descriptions of rock cmshing/sizing operations (if any); the expected distribution ofparticle sizes
ofthe gravel materials of construction; and the processes to be used to mix, place, and compact
the gravel and topsoil materials that will constitute the final admix layer.
Response la:
Procedures for mixing, placement, and testing ofthe gravel/topsoil admixture layer (rock
mulch), as well as the required gradation of the material is provided in the updated
Technical Specifications (Attachment A of the 2011 Reclamation Plan).
b. Provide key data and material testing results for component materials proposed for use in
constmcting the gravel/topsoil admix layer (e.g., plasticity index of soil; dispersive vs. non-
dispersive nature and organic content of the topsoil; specific gravity of gravel materials; gravel
particle gradation; and percentage of gravel vs. topsoil in admixture). Provide separate
calculation(s) as needed showing how parameter values were determined (e.g., void ratio,
density, and composite gradation of the final admix) for the admix layer that are used as input
into erosion calculations.
Response lb:
The erosional stability analyses for the top surface and sideslopes of the reclaimed
tailings cells are provided in Appendix G of the Updated Tailings Cover Design Report.
The material properties used for the topsoil material and gravel/topsoil admixture in the
erosional stability analyses are based on laboratory testing results presented in
Appendix A of the Updated Tailings Cover Design Report.
c. Provide information on the types of vegetation proposed to be established (e.g., type of rangeland
grass and/or other plant species) and the type(s) of plant communities that are anticipated to
Inten-ogatory 03/01A: 10CFR40 Appendix A, Criterion 4: Location and Design Requirements Page 7 of 25
evolve in the final altemative cover system over the long term (i.e., describe likely plant
succession scenarios). Assess the abilities of both planned and successive plants to protect
against erosion and support transpiration.
Response Ic:
Detailed information on the proposed plant species and ecological characteristics of the
expected plant community is provided in Appendix D of the Updated Tailings Cover
Design Report.
d. Provide an analysis of rate of soil erosion of the gravel/topsoil admix surface layer due to sheet
erosion using USLE or MUSLE (Modified Uniform Soil Loss Equation based on Utah Water
Research Laboratory MUSLE [Apt and Ruff1978]).
Response Id:
Analysis of soil erosion due to sheet flows across the top surface of the reclaimed
tailings cells is provided in Appendix G (Erosional Stability Evaluation) of the Updated
Tailings Cover Design Report.
Provide calculations demonstrating the adequacy of the proposed gravel/topsoil admix layer to
protect against erosion from overland fiow (e.g., a calculation of allowable effective stress on the
admix layer surface using the tractive forces method) expected to occur across the cover surface.
Acceptable analysis methods include those described in NUREG-1623 (NRC 2002) and include
the Temple et al 1987 tractive force (allowable shear stress) method and the "permissible
velocity" method as discussed by Chow (1959). Ifthe latter method is used, justify the selection of
Manning's "n " values used in the calculations for a conservative range ofpotential vegetation
conditions (e.g., from an essentially bare "desertpavement" type condition to a well vegetated or
grassy condition).
Response le:
The erosional stability analyses for the top surface and sideslopes of the reclaimed
tailings cells including detailed calculations are provided in Appendix G of the Updated
Tailings Cover Design Report.
/ Provide information on and justification for values of all parameters used in erosion calculations
for assessing stability of the gravel/topsoil admix layer. Demonstrate that such layer properties
are representative of the expected as-built gravel/topsoil admix layer, as opposed to simply
relying on values estimated in the literature.
Response If:
The erosional stability analyses for the top surface and sideslopes of the reclaimed
tailings cells including material properties used for the calculations are provided in
Appendix G of the Updated Tailings Cover Design Report. The gravel/topsoil admixture
material properties used for the erosional stability analyses are consistent with the
material property specifications provided in the updated Technical Specifications
(Attachment A of the 2011 Reclamation Plan).
Inten-ogatory 03/01 A: 10CFR40 Appendix A, Criterion 4: Location and Design Requirements Page 8 of 25
g. Provide information to justify the value of the maximum allowable slope necessary to prevent
initiation of gullying in the topdeck portion of the altemative cover design. Acceptable analysis
methods include those described in NUREG-1623 (NRC 2002), including the Horton/NRC
equation and the Corps of Engineers Method (NRC 2002). Provide appropriate Manning's "n "
values for a conservative range ofpotential vegetation conditions that would be considered/used
in the calculation (i.e., an essentially bare "desertpavement" type condition to a well vegetated
or grassy condition).
Response lg:
The erosional stability analyses for the top surface and sideslopes of the reclaimed
tailings cells including detailed calculations are provided in Appendix G of the Updated
Tailings Cover Design Report.
h. Redefine the proposed altemative cover design shown in Exhibit A following the Introduction to
these Round lA interrogatories to:
• Include information regarding vegetation seed type and seeding process for the upper soil
layer; and
• Define characteristics of rock riprap that will be included on the sideslope portions of the
altemative cover design, or, alternatively, state that no rock armoring would be used on the
sideslopes and provide detailed justification for not including such armoring in the cover
system.
Response lh:
Detailed information on the proposed plant species and seeding rates is provided in
Appendix D of the Updated Tailings Cover Design Report. The Revegetation Plan is
provided as Appendix J of the Updated Tailings Cover Design Report.
Evaluation of the erosion protection for the sideslopes of the tailings cells is provided in
Appendix G of the Updated Tailings Cover Design Report.
2. Refer to Section 3.3.3 (Infiltration Analysis), Section 3.3.7 (Soil Cover-Animal Intrusion), and
Attachment A, Section 5.3.2.1 (Methods) and Table 5.3.2.1-1 of the Rev 4.0 Reclamation Plan and
MWH 2010: In addition to the information requested in Round 1 Interrogatory White Mesa RecPlan
03/01 (as it remains applicable to the proposal alternative cover design), please provide the
following information for the proposed alternative tailings cell cover design:
a. Provide additional information regarding how the gravel/topsoil admix layer will be constmcted
in the altemative cover system. Discuss whether the composite admixture will be prepared away
from the disposal unit and then transported to the topdeck surface with low ground pressure
equipment, or, alternatively, created in place as the cover is constmcted. In either case, describe
and justify the constmction equipment and process. Also provide additional information
regarding the proposed loose-lift thicknesses, moisture conditioning, and placement and
compaction methods (e.g., equipment to be used and number of passes to be made by such
equipment when constmcting the sandy clayey silt layers in the alternative cover system.
Demonstrate that installation procedures will result in soil systems that are compacted to a
degree to less than or equal to the estimated "Growth Limiting Bulk Density" of the soil system,
as described by Goldsmith, et al (2001) and Gray (2002), e.g., less than or equal to
Inten-ogatory 03/01 A: 10CFR40 Appendix A, Criterion 4: Location and Design Requirements Page 9 of 25
approximately 80 to 85 % standard Proctor density for the soils used, in order to not inhibit
vegetative growth in the topdeck portion of the cover system.
Response 2a:
Procedures for mixing and placement of the gravel/topsoil admixture layer (rock mulch)
are provided in the updated Technical Specifications (Attachment A of the 2011
Reclamation Plan). Information on lift thickness, moisture conditioning, placement and
compaction methods for the cover system layers is also provided in the updated
Technical Specifications.
b. Please revise Sections 3.3.3, 3.3.7 of the text in the Reclamation Plan, and Section 5.3.2.1 and
Table 5.3.2.1-1 in Attachment A to the Reclamation Plan, to reflect the final compaction criteria
selected for the final proposed topdeck cover system, e.g., as referenced in the proposed
Preliminary Alternative Cover Design forthe White Mesa Tailings Cells (MWH 2010).
Response 2b:
The main text of the 2011 Reclamation Plan lists the compaction criteria for the ET cover
components. The compaction criteria for the cover components are also provided in the
updated Technical Specifications (Attachment A of the 2011 Reclamation Plan).
BASIS FOR INTERROGATORY
The proposed alternative cover design includes a gravel/topsoil admix layer on the topdeck portion ofthe
cover system, rather than a layer of rock riprap. This layer needs to be evaluated for adequacy with
respect to long-term erosion protection, consistent with NRC guidelines and recommendations for
evaluating erosion protection (e.g., NRC 2002). Erosion protection calculations provided in Appendix F
ofthe Reclamation Plan, Rev. 4 need to be revised to address the proposed new cover system design.
The gravel/topsoil admix layer will be unique in its characteristics, depending on the specific composition
ofthe components used in its constmction and the specific procedures used to mix, place, and compact
the layer. For this reason, specific layer properties for this admix layer (e.g., admix layer void space and
density), as they are used in erosion protection evaluations/ calculations, should be specifically
calculated for the layer (i.e., rather than using literature-derived or assumed values for these layer
properties).
Information that needs to be provided, for review, for the proposed alternative cover design also includes
information on the types of vegetation proposed to be established (e.g., type of rangeland grass and/or
other plant species) and plant communities that are anticipated to develop in the final alternative cover
system over the long term. In other words, plant succession must be addressed. This information will be
used as input in separate modeling simulations and will support certain erosion analyses, including
determination of appropriate Manning's "n " roughness coefficients for use in design analyses.
Work conducted by Goldsmith and others (2001) and Gray (2002) suggests that a compaction between
80% and 85% of the standard Proctor maximum dry density provides many of the stabilizing benefits of
higher soil compaction without jeopardizing the viability of vegetation development and growth. Use of
excessive compactive effort and/or ineffective techniques when installing the gravel/topsoil admix layer
and use of too-small loose-lift thicknesses and/or excessive compactive effort during constmction of the
portion of the underlying sandy clayey silt layers that is intended to serve as the vegetative growth
Inten-ogatory 03/01A: 10CFR40 Appendix A, Criterion 4: Location and Design Requirements Page 10 of 25
medium could result in excessive amounts of compaction in these layers, thus deterring vegetation
growth. Additional information should be provided demonstrating that these potential concerns will be
adequately addressed in the design and constmction specifications.
The sideslope portions of the final cover system will be susceptible to long-term erosion. Applicable
erosion protection design criteria (e.g., NRC 2002) suggest that rock armoring of sideslope areas could
likely be required to ensure adequate long-term erosion protection of these sideslope areas.
REFERENCES:
Apt, S.R, and Ruff, J.F. 1978. "Three Procedures for Estimating Erosion from Construction Areas. "
Symposium on Uranium Mill Tailings Management, Volume II. Geotechnical Engineering
Program, Civil Engineering Department, Colorado State University, November 20 and 21, 1978,
pp. 87-102.
Chow, V.T. 1959. Open-Channel Hydraulics, McGraw-Hill Company, Inc., New York, NY.
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. URL:
http://el. erdc. usace. army. mil/elpubs/pdf/sr2 6.pdf.
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.
MWH 2010. "Proposed Preliminary Altemative Cover Desi^ for White Mesa Tailings Cells". Letter
from Melanie Davis of MHW to Harold Roberts of Denison Mines (USA) Corp. dated October 6,
2010.
Nelson, J.D., Abt, S.R., Volpe, R.L, van Zyf D., Hinkle, NE., and Staub, W.P. 1986. Methodologies for
Evaluating Long-Term Stabilization Designs of Uranium Mill Tailings Impoundments. Prepared
for Nuclear Regulatory Commission, Washington, D.C. NUREG/CR-4620, ORNL/TM-10067.
June 1986, 151 pp.
Temple, D.M., Robinson, KM., Ahring, R.M., and Davis, A.G. 1987. Stability Design of Grass-Lined
Channels. U.S. Department of Agriculture, Agricultural Handbook No. 667, U.S. Govemment
Printing Office, Washington, D.C, 167pp.
Nuclear Regulatory Commission (NRC) 2002. Design of Erosion Protection for Long-Term Stability,
NUREG-1623, September 2002.
Inten-ogatory 03/01 A: 10CFR40 Appendix A, Criterion 4: Location and Design Requirements Page 11 of 25
INTERROGATORY WHITE MESA RECPLAN 05/OlA: 10 CFR PART 40, APPENDIX A; UAC
R317-3-1; AND UAC R317-3: CONSTRUCTION QUALITY CONTROL AND ASSURANCE
REGULATORY BASIS:
Refer to R317-3-1(1.7). 1.7. Constmction Supervision. The applicant must demonstrate that adequate and
competent inspection will be provided during constmction. It is the responsibility of the applicant to
provide frequent and comprehensive inspection of the project.
Refer to R317-3-10(4)(E). E. Construction Quality Control and Assurance. A constmction quality control
and assurance plan showing frequency and type of testing for materials used in constmction shall be
submitted with the design for review and approval Results of such testing, gradation, compaction, field
permeability, etc., shall be submitted to the Executive Secretary.
INTERROG A TOR Y STA TEMENT:
1. Refer to Section 7.0 of Attachment A and Attachment B to the Rev. 4.0 Reclamation Plan, and
MWH 2010: In addition to the information requested in Round 1 Interrogatory White Mesa RecPlan
05/01 (as it remains applicable to the proposed altemative cover design), please include information
in the CQAQC Plan regarding DUSA's plans for constructing and monitoring a Test Pad to quantify
field/constmction parameters that are specifically pertinent to demonstrating the (short-term and
long-term) performance of the altemative tailings cell cover design. Address, as part of the Test Pad
program, testing of parameters (e.g.. National Research Council 2007; Albright, etal. 2007)
including, but not necessarily limited to:
• In-situ water content testing (e.g., soil moisture profile monitoring) and monitoring for potential
changes in water content according to depth through time.
• In-situ fiux rate testing (e.g, through use of one or more pan lysimeters) and monitoring to assess
potential changes in flux rates through time.
• Physical sampling and laboratory testing for index properties, including Plasticity Index and
saturated hydraulic conductivity, and other pertinent parameters (organic matter content,
compaction properties, etc.) and monitoring to assess potential changes in these properties
through time.
• Testing for determining soil water characteristic curves (SWCCs, e.g., according to ASTM D6836
[ASTM 2008]) and monitoring for potential changes in SWCCs through time. This also includes,
but is not limited to determination of individual soil total porosity, fleld capacity, wilting point,
and residual saturation, etc.
• Relevant climatological parameters (precipitation and evaporation rates, etc.).
Response 1:
Denison is not proposing a test pad for demonstrating short- and long-term performance
of the alternative tailings cell cover system. Rather, Denison has completed extensive
modeling of the cover system for demonstrating that the cover will perform effectively for
a variety of climatic and vegetative scenarios. It may be possible to extend a portion of
the cover system beyond the edge of the first tailings cell such that the hydraulic
conditions within the cover system could be evaluated through time (in a test pad like
setting) without causing deleterious effects to the cover above the tailings. This "test
pad" would be further evaluated after approval of the cover design. Additionally,
Denison is proposing monitoring in situ performance of the alternative tailings cell cover
system as discussed below in Response 2.
Interrogatory 05/01A: 10CFR40 Appendix A; UAC R317-3-1; and UAC R317-3: Construction Quality Control and Assurance Page 12 of 25
2. Provide justiflcation for monitoring approaches and monitoring devices (e.g., use ofTDRprobes,
heat dissipation probes, pan lysimeters, and/or neutron probe access tubes, etc.) proposed for use in
the cover performance veriflcation monitoring program.
Response 2:
Denison is proposing monitoring in situ performance of the alternative tailings cell cover
system to include monitoring hydraulic conditions at nested intervals within the soil
profile at three locations within the first tailings cell that is reclaimed. The depth intervals
that are evaluated would depend on the final design specifications of the approved
alternative cover system, but would likely represent data collected from three depths.
The first depth interval would be located immediately below the soil-gravel admixture
(0.6 feet), the second depth interval would be located near the midpoint of the maximum
rooting depth (1.5 feet), and the third depth interval would be located at or slightly below
the maximum rooting depth (3.8 feet) but above the proposed upper compacted layer.
The pertinent hydraulic properties to be monitored would include soil water tension and
volumetric water content. Soil water tension would be measured with a heat dissipation
probe, while volumetric water content would be measured with a time domain
reflectometry (TDR) probe. The use of these monitoring methods is consistent with what
was used to monitor conditions as part of the Alternative Cover Assessment Program
(ACAP). Changes in water content through time can be used to assess changes in soil
water storage through time. Measurements of volumetric water content and soil water
tension can be related to the soil water retention and hydraulic conductivity curves to
estimate a water flux rate and cover performance through time.
Climatological parameters are currently being measured at the site and include
precipitation, wind speed, and wind direction. In addition, air temperature and
barometric pressures are measured monthly for environmental air station calibrations.
Based on this information in addition to supplemental climate data from the nearest
weather station (Blanding, Utah station 420738), the daily amount of evapotranspiration
can be computed.
3. Describe how information on natural analogs (existingplant communities and existing natural soil
proflles at the borrow source site(s) or other sites that exhibit characteristics similar to those ofthe
flnal cover system at various times in its design life) will be used to complement the results ofthe
CQAQC Test Pad testing program/cover performance program discussed above. Describe possible
future changes in climate states and extreme precipitation events that were considered as part of the
design ofthe proposed alternative cover and in selecting analog sites for inspection/investigation.
Response 3:
See Responses 1 and 2. Denison is not currently proposing to construct a test pad.
4. Provide a Constmction Quality Assurance Constmction Quality Control (CQACQC) plan containing
detailed information on constmction procedures and equipment to be used for constructing the
proposed alternative flnal cover system and the Test Pad cover system. Describe the acceptable
tolerances that will apply when measuring flnal grades during constmction of the cover and the Test
Inten-ogatory 05/01A: 10CFR40 Appendix A; UAC R317-3-1; and UAC R317-3: Constmction Quality Control and Assurance Page 13 of 25
Pad cover system. Identify testing frequencies, equipment, and methods for testing of constmcted
flnal grades. Provide information demonstrating that the specifled grading tolerances for the flnal
cover and Test Pad cover constmction can be reliably, accurately, and consistently measured in the
fleld throughout the cover constmction effort. Provide case studies/examples from peer-reviewed
literature that clearly demonstrate that a flnal cover system constmcted to a similar scale and under
similar site conditions and using similar soils and equipment as the proposed cover system having a
topdeck slope of (only) 0.2 % can be effectively constmcted with a positive slope inclination
maintained throughout the entire cover surface area. Provide information demonstrating that long
term, post-constmction settlement and/or subsidence within the reclaimed tailings embankment will
not result in any areas that could allow ponding of water to occur on the cover surface and/or result
in increased percolation into the cover system.
Response 4:
The procedures for constructing and testing the alternative cover system are provided in
the Technical Specifications and Construction Quality Assurance and Quality Control
Plan (Attachments A and B of the 2011 Reclamation Plan). Information regarding
acceptable grading tolerances and testing frequencies is also provided in Attachments A
and B of the 2011 Reclamation Plan. Denison is not currently proposing to construct a
test pad (see Responses 1 and 2).
The current design for the proposed cover system has top surface slopes ranging from
0.5 to 1 percent. Covers with similar slopes have been constructed for Uranium Mill
Tailings Radiation Control Act (UMTRCA) Title I and II sites including;
Falls City Title I site in Texas (less than 1% cover slopes);
Bluewater Title II site in New Mexico (0.5 - 4% cover slopes);
Conquista Title II site in Texas (0.5 - 1% cover slopes);
Highland Title li site in Wyoming (0.5 - 2% cover slopes);
Panna Maria Title II site in Texas (0.5% cover slopes);
Ray Point Title II site in Texas (0.5 - 1% cover slopes); and
Sherwood Title il site in Washington (0.25% cover slopes).
Settlement analyses for the proposed cover design are provided in Appendix F of the
Updated Tailings Cover Design Report. Settlement of the thickest profile of tailings in
Cells 2, 3, and 4A and 4B is anticipated to range from 2 to 10 inches after placement of
interim cover and dewatering. Settlement monuments currently exist in Cell 2 and the
eastern portion of Cell 3 where interim cover has been placed. For the remainder of Cell
3, and for Cells 4A and 4B, settlement monuments wili be installed after placement of
interim cover. Monuments wili be monitored on a regular basis in order to verify that 90
percent of the settlement due to dewatering and interim cover placement has occurred
prior to construction of the final cover. Additional fill, if necessary, will be placed in any
low areas in order to maintain positive drainage of the cover surface. Additional
settlement due to the construction of the final cover is estimated to be on the order of 5
to 6 inches. The estimated amount of additional settlement is sufficientiy low such that
ponding is not expected with cover slopes of 0.5 to 1 percent.
Intenogatory 05/01A: 10CFR40 Appendix A; UAC R317-3-1; and UAC R317-3: Construction Quality Control and Assurance Page 14 of 25
5. Provide information on seed/seeding application rates and acceptable germination levels for
promoting vegetation (grass) growth on the flnal cover. Provide information in the CQAQC Plan on
application rates and procedures to be used for measuring/confirming that specifled application rates
are achieved
Response 5:
Detailed information on the proposed plant species and seeding rates is provided in
Appendix D of the Updated Tailings Cover Design Report. The Revegetation Plan is
provided as Appendix J of the Updated Tailings Cover Design Report, information in the
Revegetation Plan on seeding application rates and quality assurance/quality control
procedures is also included in the Construction Quality Assurance and Quality Control
Plan (Attachment B of the 2011 Reclamation Plan).
BASIS FOR INTERROGATORY
A cover system Test Pad capable of assisting in conflrming the performance of the proposed alternative
cover system should be constmcted and monitored. The proposed alternative cover design incorporates
more loosely compacted soil layers, and a surficial rock riprap layer is no longer to be included. The
alternative cover system appears to be intended to serve as a water balance cover system (an
evapotranspiration [ET]-type cover where the cover is designed to act not as a barrier, but as a sponge
or "reservoir" for storing moisture generated during precipitation events, for subsequent release back to
the atmosphere as ET, with plants established on the cover surface designed that survive on the naturally-
occurring precipitation capable of promoting vegetation growth to enhance evapotranspiration).
Characteristics ofthe proposed alternative cover will inevitably change in the long term in response to
climate, pedogenesis, and ecological succession (Albright, etal 2007; Benson, etal 2007). Use ofa less
compacted gravel/topsoil admixture layer and more loosely compacted underlying soil layers in the cover
without the riprap layer could render the alternative cover susceptible to post-constmction changes in
certain physical and hydraulic properties of the cover. For example, relatively large changes in moisture
content (wetting and drying cycles) in the cover system and plant root development would be expected to
occur through time during the post-closure period (200-1,000 years) which could eventually lead to
changes in some hydraulic properties of the soil cover system. Changes could include creation of larger
pore spaces and a broader pore size distribution as a result of wet-dry cycles (desiccation) and
reductions in soil density due to frost heave action, which could ultimately lead to changes in hydraulic
properties. By comparison, the conditions associated with the cover design presented in the Rev. 4.0
Reclamation Plan could have been expected to reduce evaporation and enhance water storage in the
cover (e.g., Groenevelt, et al 1989; Kemper, et al 1994), and thus provide some degree of buffering
(insulating) benefit against larger moisture fluctuations in the upper portion of the underlying soil
layer(s) in the cover.
Comparisons of data collected from a depth of 30 cm (1 foot) within water balance covers constmcted at
different fleld sites in the Altemative Cover Assessment Program at the time of constmction and data
collected 2 to 4 years following constmction of those covers indicate potentially large changes in
saturated hydraulic conductivity (increases by as much as 10,000 times); increases in the van Genuchten
parameter a (an increase by as much as 1,000 times was observed); and increases in the saturated
volumetric water content and the van Genuchten parameter n (e.g., Benson, et al 2007). Results of such
studies indicated that, depending on the speciflc materials and constmction methods, actual as-built
conditions, and actual climatic conditions present, the largest changes in soil cover properties (at least in
the upper 1-foot zone) were observed in those water balance covers that are comprised of denser, flne-
Intenogatory 05/01 A: 10CFR40 Appendix A; UAC R317-3-1; and UAC R317-3: Construction Quality Control and Assurance Page 15 of 25
textured soils that have more uniform pore space distributions. Less is known about how changes in
hydraulic properties vary with depth in ET cover systems evaluated.
Plasticity Index can be a useful indicator for assessing volume changes. Soil Water Characteristic Curves
for soils used in the cover system could be expected to change with time, based on post-constmction
changes that may occur in the controlling soil parameters of the soil layers. Such changes could modify
soil moisture storage/retention, and other hydraulic properties.
Monitoring the proposed altemative cover system or monitoring of a Test Pad simulating the cover
system components and geometry) to assess the long-term performance of the altemative cover is needed
to verify the characteristics and infiltration performance of the constmcted cover system as well as to
gain confldence in understanding long-term changes that may occur in the physical/hydraulic properties
ofthe alternative cover system over time following its constmction.
REFERENCES:
Albright, W.H., Waugh, W.J, and Benson, CH. 2007. "Alternative Covers: Enhanced Soil Water Storage
and Evapotranspiration in the Source Zone. " Enhancements to Natural Attenuation: Selected
Case Studies, Early, T.O. (ed), pp 9-17. Prepared for US. Dept. of Energy by Washington
Savannah River Company, WSRC-STI-2007-00250. URL:
http://www. dri edu/images/stories/research/programs/acap/acap-publications/l O.pdf
ASTM (American Society for Testing and Materials) 2006. ASMT D6836 - 02(2008)e2: Standard Test
Methods for Determination of the Soil Water Characteristic Curve for Desorption Using a
Hanging Column, Pressure Extractor, Chilled Mirror Hygrometer, and/or Centrijuge. ASTM,
West Conshohocken, Pennsylvania.
Benson, CH, Sawangsuriya, A., Trzebiatowski, B., and Albright, W.H. 2007. "Postconstruction Changes
in the Hydraulic Properties of Water Balance Cover Soils ", Journal of Geotechnical and
Geoenvironmental Engineering, 133:4, pp. 349-359.
Groenevelt, P.H., P. van Straaten, V. Rasiah, and J Simpson 1989. "Modiflcation in Evaporation
Parameters by Rock Mulches", Soil Technology 2:279-285 (1989).
Kemper, W.D., A.D. Nicks, and A.T. Corey 1994. "Accumulation of Water in Soils under Gravel and
Sand Mulches ", Soil Science Society of America Journal 58:56-63 (1994).
MWH 2010. "Proposed Preliminary Altemative Cover Design for White Mesa Tailings Cells". Letter
from MHWto Harold Roberts of Denison Mines (USA) Corp. dated October 6, 2010.
National Research Council 2007. Assessment of the Performance of Engineered Waste Containment
Barriers. Board of Earth Sciences and Resources. The National Academies Press, Washington,
D.C, 2007, 134pp.
inten-ogatory 05/01A: 10CFR40 Appendix A; UAC R317-3-1; and UAC R317-3: Constmction Quality Control and Assurance Page 16 of 25
INTERROGATORY WHITE MESA RECPLAN 09/OlA: UAC R313-25-7; UAC R313-25-8; UAC
R317-6-l(6)6.1 : WATER BALANCE DESIGN CONTROL FEATURES IN COVER SYSTEM
REGULATORY BASIS:
UAC R317-6-1(6)(6.1)(A) Implementation. Unless otherwise determined by the Executive Secretary, the
application for a permit to discharge wastes or pollutants to ground water shall include the following
complete information:
UAC R317-6-1 (6)(6.1)(G) Implementation. Information which shows that the discharge can be controlled
and will not migrate into or adversely affect the quality of any other waters of the state, including the
applicable surface water quality standards, that the discharge is compatible with the receiving ground
water, and that the discharge will comply with the applicable class TDS limits, ground water quality
standards, class protection levels or an alternate concentration limit proposed by the facility.
INTERROGATORY STATEMENT:
Although no Round 1 interrogatory was developed that focused speciflcally on design features included in
the flnal cover system for controlling the water balance within the reclaimed tailings embankment
following closure (namely, no Interrogatory White Mesa Recplan 09/01 exists) this interrogatory is
provided to address certain issues related to the design of the alternative cover system design that were
not germane to the existing authorized rock cover system design. In addition, it is acknowledged that
review ofa Revised Inflltration and Contaminant Transport (ICTM) Report is being conducted separately
and is still in progress and that additional issues and/or interrogatory items may arise from further
review and discussions with DUSA as an outcome of that review. Nonetheless, the following items are
provided here since the issue of long-term water balance within the closed tailings embankment is
integrally connected to details of the flnal cover system design.
1. Refer to Sections 3.2.2, 3.3, Section 5 of Attachment A, Figures A-5.1-1 through A-5.1-3, and
Table A-5.3.2.1-1 ofthe Rev 4.0 Reclamation Plan, and MWH 2010: Please provide the following
information:
• Provide information regarding potential long-term conditions in the proposed alternative cover
system that has been considered in developing the cover design. Include information on the
saturated hydraulic conductivity values expected to be achieved for the as-built soil layer
components in the proposed alternative cover system. Also provide information on the estimated
range of long-term hydraulic conductivity values projected to occur within each of the soil layer
components in the cover (e.g, under long-term, degraded cover conditions). Describe the
assumptions that have been made with respect to key variables that influence the cover design,
including, but not limited to: (1) Absence of ongoing maintenance of the cover system and lack of
maintenance/removal of leachate from tailings cell sumps in the future; (2) nature and extent of
degraded conditions projected to occur in the cover (and cell liner systems) over the required
design life of the embankment [200-1,000 years]; (3) magnitude ofpotentially wetter future
precipitation conditions that may occur at the site over the embankment's required design life;
(4) presence and distribution of different plant species/communities and animal-induced
burrowing that could occur in the cover system over the long term; and (5) other degraded
conditions that could develop within the cover system (and liner system) as a result of other
degradation mechanisms. Describe and quantify, to the extent practicable, uncertainties that are
associated with assumptions made with respect to these variables.
Interrogatory 09/01A: UAC R313-25-7; UAC R313-25-8; UAC R317-6-1(6)6.1: Water Balance Design Control Features in Cover System Page 17 of 25
Response 1 (bullet 1):
The hydraulic modeling of the alternative cover is presented in the Revised infitration
and Contaminant Modeling (ICTM) Report (MWH, 2010).
The hydraulic properties used as input for the infiltration model are summarized in Table
1. These properties were selected to represent long-term conditions within the cover
system, and utilized functions based on particle size distribution and compaction tests on
stockpiled soils. The water storage layer, which would comprise the majority of the soil
cover profile, was assumed to be compacted to 85 percent of standard Proctor dry
density.
fable 1. Cover Model Properties Used in the IH ydrus Moc els
Mode/
Layer ' {.Zone in Modef^; th ickness
;f ^y
Residual..
:|)y:iso||:}j|;ii
waters;
i;i:i,ebhteht'i
WyfzMt^y/^' |(#|^J
Saturated;
soil water
:.^^^|^y<>|)J|;:
''Zi'.'>&•'•'- '•i!iZ'y,5yy'y' •
. Curve fitting ,
' paranietefs in'
the soil water
y retehtibn
;^ Saturated i/
li^^'^Hj^raijli^
-conductivity
i in the ; ^
t|;B^>^ica!i|;;,i
^i-'1^lrectlb"h';*^i,
•yy^m^yy^'-^^
iins^(crfi/d>v:*-t^
Mode/
Layer ' {.Zone in Modef^; th ickness
;f ^y
Residual..
:|)y:iso||:}j|;ii
waters;
i;i:i,ebhteht'i
WyfzMt^y/^' |(#|^J
Saturated;
soil water
:.^^^|^y<>|)J|;:
''Zi'.'>&•'•'- '•i!iZ'y,5yy'y' •
z§yia'.$h
Mem!)
'y^$in'y%
Wgf%
;^ Saturated i/
li^^'^Hj^raijli^
-conductivity
i in the ; ^
t|;B^>^ica!i|;;,i
^i-'1^lrectlb"h';*^i,
•yy^m^yy^'-^^
iins^(crfi/d>v:*-t^
Model 1: Monolithic ET Cover''
1 Erosion Protection 15 0.045 0.254 0.0145 1.406 5.6
2 Water Storage &
Radon Attenuation 107 0.055 0.404 0.0145 1.406 7.4
3
Upper Platfonn Fill
(High Compaction)
Radon Attenuation
86 0.046 0.334 0.0229 1.261 3.6
4
Lower Platfonn Fill
(Base Grade)
Radon Attenuation
76 0.059 0.439 0.0125 1.461 10.4
While some minor changes to the soil structure could occur post-construction, the
stockpiled soils are generally of low plasticity, and would be compacted to densities
similar in natural conditions, such that post-construction changes would be minimized.
Furthermore, the values used as input to the numerical model correspond to the range of
post-construction hydraulic properties presented by Benson et al. (2007). Therefore, the
hydraulic properties used for the infiltration model represent post-construction
conditions, and the absence of ongoing maintenance of the cover system should not be
an issue providing the vegetation is successfully established.
A groundwater flow model was used to evaluate the removal of leachate from the tailings
ceil sumps for Cells 2 and 3. For the tailings ceil model, no-flow boundaries were
assumed to surround the domain, and a net flux rate from the cell was assumed across
the entire domain. This assumed flux rate represented the combination of potential
fluxes from the cell through the liner and potential infiltration into the cell through the
cover. The net flux rate was calculated using the average infiltration rate through the
cover predicted by the HYDRUS-1D tailings cover model and the potential flux rate
through the bottom of Cells 2 & 3. The tailings cell model was calibrated by varying the
drain conductance term until the flow rates approximately matched the 2007 dewatering
rates (average rate of 12.5 gpm) and average water levels of 20 feet above the liner.
The MODFLOW dewatering model predicts that the tailings would drain down
nonlinearly through time, reaching an average saturated thickness of 3.5 feet (1.07 m)
after 10 years of dewatering.
Inten-ogatory 09/01A: UAC R313-25-7; UAC R313-25-8; UAC R317-6-1 (6)6.1: Water Balance Design Control Features in Cover System Page 18 of 25
A dewatering model was not constructed for Cells 4A and 4B because dewatering rates
were estimated by Geosyntec Consultants (2007). Water levels in Cell 4A were
estimated to decline to less than one foot after approximately six years of dewatering.
Cells 4A and 4B is estimated to be dewatered significantly faster than Cells 2 and 3 due
to the more extensive slimes drain network. The dewatering system in Cell 4B is
assumed to be designed similarly to Cell 4A, thus dewatering rates were assumed to be
similar.
Therefore the lack of maintenance/removal of leachate from tailings cell sumps in the
future should not significantly affect the long-term potential flux rates through the liner
since the amount of recharge through the cover and buildup of head on the liner (and
subsequent potential water flow through the liners) should be minimal over the required
design life.
The nature and extent of degraded conditions projected to occur in the cell liner systems
over the required design life of the embankment is described in Appendix L (Evaluation
of potential water flow through the tailings cell liners) of the ICTM Report (MWH, 2010).
The magnitude of potentially wetter future precipitation conditions over the design life
was evaluated as part of a sensitivity analysis. To test the importance of simulating how
increased precipitation could influence the transport of water through the monolithic
evapotranspiration (ET) cover, the HYDRUS model was run using different assumptions
aimed at characterizing an anticipated scenario and increased precipitation scenario.
Rates of model-predicted water flux entering the tailings cells were compared between
simulations using different input assumptions.
The anticipated climate record for the White Mesa Mill was taken from historic data
recorded at the Blanding weather station between 1932 and 1988. To evaluate the
effects of long-term accumulation of water in the water storage layer and ET cover
performance, the three wettest years on record were inserted into the climate record.
Inclusion of consecutive-wet years is the recommended procedure for evaluating the
effects of increased precipitation on infiltration rates through an ET cover.
The average water flux predicted to enter the tailings cells was 0.45 mm/yr and 2.0
mm/yr for the anticipated and increased precipitation scenarios, respectively. The
model-predicted water flux through the ET cover indicates that the available storage
capacity of the cover should be sufficient to significantly minimize infiltration.
Information regarding the absence of ongoing maintenance of the cover system
presence and distribution of different plant species/communities and animal-induced
burrowing that could occur in the cover system over the long term is provided in
Appendix D of the Updated Tailings Cover Design Report regarding the establishment of
vegetation.
Evaluate and provide information regarding the need to include a low-permeability barrier
component (e.g., an HDPE geomembrane and a geosynthetic clay liner [GCL]) in the altemative
cover system for limiting long-term vertical movement of moisture through the cover.
Alternatively, provide detailed information that clearly demonstrates why such a low-
permeability barrier layer, which NRC recommends, be included in final tailings cell reclamation
interrogatory 09/01A: UAC R313-25-7; UAC R313-25-8; UAC R317-6-1(6)6.1: Water Balance Design Controi Features in Cover System Page 19 of 25
covers (NRC 2003, Section 2.7), is not warranted or necessary. Provide information
demonstrating that the proposed alternative cover system would provide an adequate level of
long-term reduction of vertical moisture movement through the cover to both minimize the
potential for long-term "bathtubbing" of liquid within the closed tailings embankment and
restrict the transport of contaminants from the closed tailings embankment to subsurface
groundwater throughout the design life [200-1,000 years] of the embankment to levels equivalent
to, or better than, a flnal cover system that includes such a low-permeability component.
Response 1 (bullet 2):
A composite liner system has not been proposed because infiltration modeling
presented in the ICTM Report (MWH, 2010) has indicated that the ET cover design is
the preferred alternative to minimize infiltration and meet the radon attenuation standard.
The model-predicted average long-term water flux rate through the proposed monolithic
ET tailings cell cover was 0.45 mm/yr. The average long-term water flux rate
corresponds to approximately 0.1 percent of the average annual amount of precipitation
recorded at the Blanding weather station.
To evaluate the potential for build-up of water in the tailings ("bathtub effect"), the long-
term average water flux rate through the tailings cell cover system (predicted with the
infiltration model) was used to calculate the amount of water entering the tailings during
the 200-year regulatory timeframe. The amount of water expected to migrate through
the cover and enter the tailings cells was then used to calculate the maximum potential
rise in water levels in the tailings assuming no water flow through the liners.
The volume of water estimated to enter the tailings after 200 years is equal to 90
millimeters (0.3 feet) of water. Assuming a tailings porosity of 57 percent, the calculated
water-level rise on the liner is approximately 160 millimeters (0.53 feet). Consequently,
a significant build-up of water ("bathtub effect") within the cells is not anticipated and the
leachate head within the tailings is not predicted to rise above or over-top the maximum
liner elevation (which typically is greater than 20 feet above the bottom of the cell),
meeting the requirement of the Groundwater Discharge Permit (Part I.D.8).
Evaluate and provide information regarding the need for including a capillary break or lateral
drainage and/or cobble layer in the topdeck portion of the proposed alternative cover, for further
limiting vertical downward movement of moisture through the cover system and into the tailings.
Provide information demonstrating that omitting such a design feature - which could provide a
means of virtually precluding "breakthrough " of excess moisture levels in the cover into the
tailings at a semi-arid to arid site as is the case for the White Mesa Site - will not jeopardize the
capacity ofthe altemative cover for minimizing long-term downward vertical movement of
moisture through the cover system throughout the requiredpostclosure performance period
(200-1,000 years). See also Interrogatory RecPlan 02/01 A: 10CFR40 Appendix A, Criterion 1:
Permanent Isolation without Ongoing Maintenance, above. If further analysis indicates that a
lateral drainage layer is needed in the flnal cover system, based on the proposed flnal cover
grading configuration and cover topdeck slope lengths, evaluate and provide information
regarding the need for including intermediate discharge/drain outlets and/or higher
transmissivity lateral drains in the drainage layer design in the cover in order to reduce the water
budget (inflltration) that could come into contact with the tailings during the postclosure
performance period.
Inten-ogatory 09/01A: UAC R313-25-7; UAC R313-25-8; UAC R317-6-1 (6)6.1: Water Balance Design Control Features in Cover System Page 20 of 25
Response 1 (bullet 3):
A cover design sensitivity analysis was completed to determine if an ET cover system
with a capillary break would significantly reduce long-term infiltration rates into the
tailings cells. The model predictions indicated that the inclusion of a capillary break
results in a moderate reduction of infiltration compared to the proposed monolithic cover
(see Table 2). However, performance of the cover design with a capillary break does
not account for reduced performance of the gravel layer due to migration of fines into the
gravel layer. Migration of fines into the gravel layer would produce a material type
similar to the overlying soil and would result in higher rates of infiltration (comparable to
results predicted for the monolithic ET cover design). The potential migration of fines
could be minimized by the inclusion of filter layers; however, inclusion of such materials
would significantly increase the difficulty to construct the cover system and lead to
uncertainty in performance. Given the simplicity, the monolithic ET cover can be
constructed with greater certainty and quality assurance.
Table 2. Average Infiltration Rate Predicted to Enter the Top of the Tailings Cells for the
Model ^ Cover Design
Water Flux
(mm/yr)
Water Flux
(% of Average Annual
Precipitation)
Amount of water entering-
tailings after 200 years
Model 1 Monolithic ET cover 0.45 0.14% 0.09 m (0.29 ft)
Model 2 ET cover with a
connpacted clay layer 0.20 0.062% 0.04 m (0.13 ft)
Model 3 ET cover with a gravel
layer 0.11 0.036% 0.02 m (0.066 ft)
Model 4 Rock cover with a
compacted clay layer 34 11% 6.7 m (22 ft)
Note: The average annual precipitation for the 57-year climate record was recorded 1932-1988.
An internal drainage layer was not included in the design because the majority of
precipitation would be consumed within the cover, and the relatively flat slope of the
surface would not dictate installation of a drainage layer.
Evaluate and provide information on the applicability ofpublished individual or joint NRC-EPA
guidance related to the conceptual design of LLRW disposal facilities that contain low-
permeability liner components to the design of the cover system for the tailings cells at the White
Mesa Mill Facility. Provide information that clearly demonstrates that the proposed altemative
cover system will not lead to potential bathtubbing of liquid within the tailings embankment
during the postclosure period when no active maintenance would be performed at the facility and
under the scenario involving long-term (degraded) conditions present in the cover system.
Provide quantitative estimates of potential long-term leachate head buildup amounts on liner
systems for each disposal cell where the liner system characteristics (e.g., PVC/compacted
subgrade, double composite HDPE/GCL liner systems, etc.) differ between the various disposal
cells. Provide calculations (e.g., using methods in Giroud 1997) of leakage rates through each
type of liner system that consider the range of uncertainties associated with: (1) the long-term
hydraulic performance of each liner system; (2) the long-term hydraulic performance of the cover
system at limiting downward vertical movement of moisture within the tailings embankment,
given potential long-term degradation of the cover system materials; and (3) extent and duration
of dewatering occurring within the various tailings disposal cells, during the embankment's
required performance period.
interrogatory 09/01A: UAC R313-25-7; UAC R313-25-8; UAC R317-6-1(6)6.1: Water Balance Design Control Features in Cover System Page 21 of 25
Response 1 (bullet 4):
Responses to the above concerns have been provided throughout this interrogatory and
in Appendix L of the ICTM Report (MWH, 2010).
Provide information evaluating potential worst-case/abnormal long-term leakage rates through
the various cell liner systems that consider: (1) the uncertainties associated with the potential
(progressive) changes in the number, size, and types of defects in the geosynthetic liner systems
that might occur during the required performance period of the tailings embankment, including
circular defects and linear [e.g., stress] cracks, etc.) as described in the peer-reviewed literature;
(2) uncertainties associated with the extent and duration of dewatering operations that may occur
within the various tailings cells active life, and during the embankment's required performance
period; and (3) uncertainties associated with potential long-term inflltration rates through the
(degraded) final cover system.
Response 1 (bullet 5):
As mentioned previously as a response to this interrogatory, the nature and extent of
degraded conditions projected to occur in the cell liner systems over the required design
life ofthe embankment is described in Appendix L ofthe ICTM Report (MWH, 2010).
In developing a response to this interrogatory, prior review comments and Requests for
Additional Information (RFIs) previously submitted to DUSA by the UDEQ DRC on the ICTM
report should also be considered and addressed as they apply to the proposed altemative cover
design depicted in Exhibit A. These documents include, but are not limited to: DRC's Request for
Additional Information (RFI) letter dated Febmary 2, 2009, and DRC's email dated September 3,
2009 (DRC 2009a and 2009b, respectively).
Response 2:
Some of the comments mentioned in this interrogatory have previously been brought up
by the UDEQ DRC and addressed by Denison in writing (December 1, 2009 response to
the RFI) and through the submission ofthe ICTM Report (MWH, 2010).
References for Responses to interrogatory 09/01 A: UAC R313-25-7; UAC R313-25-
8; UACR317-6-1(6)6.1
Benson, C.H., A. Sawangsuriya, B. Trzebiatowski, and W.H. Albright, 2007.
Postconstruction Changes in Hydraulic Properties of Water Balance Cover Soils.
In Journal of Geotechnical and Environmental Engineering, pp. 349-359. April.
Geosyntec Consultants, 2007. Analysis of Slimes Drains for White Mesa Mill - Cell 4A,
Computations submitted to Denison Mines, May 12.
MWH, Inc. (MWH), 2010. Revised Infiltration and Contaminant Transport Modeling
Report, White Mesa Mill Site, Blanding, Utah. Prepared for Denison Mines
(USA) Corporation. March.
Inten-ogatory 09/01 A: UAC R313-25-7; UAC R313-25-8; UAC R317-6-1 (6)6.1: Water Balance Design Control Features in Cover System Page 22 of 25
BASIS FOR INTERROG A TORY:
The proposed altemative cover design does not include a low-permeability component/low-permeability
barrier. In that regard, the proposed alternative cover does not appear to be consistent with NRC
guidelines and recommendations relating to standard acceptance criteria for evaluating tailings
reclamation cover designs. NUREG-1620 (NRC 2003), Section 2.7, specifies that a goal of a tailings
reclamation plan/decommissioning plan is to ensure that the disposal cell cover has a component having
minimal hydraulic conductivity, and provides the complimentary functions of both limiting radon
emissions from (also see Rd 1 Interrogatory White Mesa Recplan 04/01 addressing radon emissions), and
limiting water infiltration into, [the] stabilized mill tailings. The discussion in Section 2.7 of NRC 2003
suggests that NRC contemplates that a cover system containing a low-permeability component having a
properly field-and-laboratory-testing-verified saturated hydraulic conductivity value oflx 10'^ cm/sec or
less is sometimes considered to be generally acceptable.
Recent studies (e.g., Scalia and Benson 2011) describe results of testing of exhumed GCLs that were
previously installed in final cover systems immediately above a compacted soil subgrade and immediately
beneath a polyethylene synthetic geomembrane that had been left in place in the covers between about 5
and 7 years. Results of laboratory testing of exhumed GCL samples that had hydrated rapidly to at least
50% water content and had experienced osmotic swell indicate that the GCL samples essentially retained
their initial low hydraulic conductivity. These results provide evidence that including a composite
GCL/geomembrane low-permeability barrier in the final cover and ensuring that it would rapidly achieve
this level of hydration and swell would likely be beneficial in helping to achieve the objective (per
NUREG-1620) of reducing (long-term) downward movement of moisture through the fmal cover into the
tailings. Such a reduction would help minimize the potential for bathtubbing within the closed tailings
embankment and minimize potential long-term releases from the base of the embankment during the post-
closure post-maintenance period following final cover placement.
Inclusion ofa capillary break or lateral drainage layer and/or cobble layer (accompanied by appropriate
filter layers as needed) in a final cover would help contribute toward achieving the desired water balance
in the cover, i.e., the promotion of evapotranspiration relative to the downward movement of water into
the tailings (e.g., see DOE 1989; Stormont and Morris 1998), as well as help provide a barrier to deep
root penetration and minimize upward movement of contaminants (within the cover) via capillary forces-
See also Interrogatory RecPlan 02/01 A: 10CFR40 Appendix A, Criterion 1: Permanent Isolation without
Ongoing Maintenance, above. These benefits would be achieved by virtue of the incorporated
capillary/drainage/cobble layer, only allowing significant quantities of water to drain out of and move
downward from the overlying soil layer component when the overlying soil is completely saturated.
Additionally, research results (e.g., Soongand Koerner 1997; Thiel and Stewart 1993, etc.) indicate that
conventional model predictions have often underestimated percolation rates into lateral drainage layers
that have been incorporated into flnal cover systems, leading to slope failures at some facilities.
Some ofthe tailings cells (e.g.. Cells 4A and 4B) contain composite of very low-permeability liners under
the tailings, including GCL and geomembrane components (having as-built saturated hydraulic
conductivities less than 1 x 10'^ cm/sec). Use of a cover system that does not include a very low-
permeability component of equal or lower permeability than the liner components could create the
potential for future buildup of liquids within the tailings embankment following closure due to net
inflltration rates through the cover exceeding net leakage rates through the liner system over the long
term. Information needs to be provided that demonstrates that the selected flnal cover design will not
result in the creation of this bathtub effect within the closed embankment.
Published information (e.g., EPA 2002, Hsuan et al 2004; Rowe and Rimal 2008; others) suggests that
the potential exists for cracks (e.g., stress cracks) to occur in the HDPE geomembrane liners (in Cells 4A
Interrogatory 09/01A; UAC R313-25-7; UAC R313-25-8; UAC R317-6-1 (6)6.1: Water Balance Design Control Features in Cover System Page 23 of 25
and 4B) and/or the PVC liners (in Cells 2 and 3) in the tailings disposal cells during the tailings
embankment's required performance period. Cracking might occur as a result of one or more factors
including: (1) the stress crack resistance and the yield stress of the HDPE geomembrane liner used in
each cell depending on its age and manufacturing source; (2) degree of long-term antioxidant depletion
and/or embrittlement that may occur in the various HDPE geomembrane liners over the liner's service
life; (3) tensile stresses and wrinkles that might be present in each cell liner system; (4) type and amount
of plasticizers and rate of post-installation plasticizer loss that may occur in the PVC geomembrane
liners (Cells 2 and 3); and (5) other possible factors. Similar factors could also lead to changes in size
and/or shape, over time, of any circular defects that may be present in the liners as a result of installation
or subsequent long-term degradation processes occurring in the liner material
REFERENCES:
DOE (U.S. Department of Energy) 1989. Technical Approach Document, Revision II. UMTRA-DOE/AL
050425.0002. Albuquerque, New Mexico.
DRC 2009a. "White Mesa Uranium Mill, Ground Water Discharge Permit No. UGW370004. Inflltration
and Contaminant Transport Modeling Report: DRC Review Comments, Request for Additional
Information, " Febmary 2, 2009 Letter from Tom Rushing to David Frydenlund, 9 pp.
DRC 2009b. "Denison Mines: Further Thought on Meeting Yesterday - Radon Control Issues
September 3, 2009 Email from Loren Morton to Harold Roberts, lp.
EPA 2002. Assessment and Recommendations for Improving the Performance of Waste Containment
System. EPA/600/R-02/099, 2002; Compiled by Bonaparte, R., Daniels, D., and Koerner, R.M.
Giroud, J.P. 1997. "Equations for Calculating the Rate ofLiquid Migration Through Composite Liners
Due to Geomembrane Defects. " Geosynfhetics International, Vol 4, Nos. 3-4, pp. 335-348.
Hsuan, Y.G., Schroeder, H.F., Rowe, K, Greenwood, J, Cazzufl, D., and Koerner, R. M. 2008. Long-
Term Performance of Geosynthetics. EuroGeo4 Keynote Paper, 40 pp.
MWH 2010. "Proposed Preliminary Altemative Cover Design for White Mesa Tailings Cells". Letter
from MHWto Harold Roberts of Denison Mines (USA) Corp., dated October 6, 2010.
NRC (U.S. Nuclear Regulatory Commission) 2003. Standard Review Plan for the Review ofa
Reclamation Plan for Mill Tailings Sites under Title II of the Uranium Mill Tailings Radiation
Control Act of1978, Rev. 1. Washington, D.C, June 2003.
Rowe, R. K., and Rimaf S. 2008. "Aging and Long-term Performance of Geomembrane Liners,"
Geoamericas 2008, Cancun, Mexico, March. 2-5, 2008., 10pp.
Scalia, J, and Benson, CH. 2011. "Hydraulic Conductivity of Geosynthetic Clay Liners Exhumed from
Landflll Final Covers with Composite Barriers ", Joumal of Geotechnical and Geoenvironmental
Engineering, Vol 137, No.l, January 1, 2011: pp. 1-13.
Soong, T.Y., and Koerner, RM. 1997. The Design of Drainage Systems over Geosynthetically Lined
Slopes. GRI Report #19.
Stormont, J And Morris, C. 1998. "Method to Estimate Water Storage Capacity of Capillary Barriers,"
Journal of Geotechnical and Geoenvironmental Engineering 124: pp. 297-302. URL:
http://ro.uow.edu.au/engpapers/208/
Interrogatory 09/01A; UAC R313-25-7; UAC R313-25-8; UAC R317-6-1 (6)6.1: Water Balance Design Control Features in Cover System Page 24 of 25
Thiel, R.S., and Stewart, M.G. 1993. "Geosynthetic Landflll Cover Design Methodology and Constmction
Experience in the Pacific Northwest", Proceeding: Geo '93, Vancouver, B.C. IFAI. Pp. 1131-
1144.
U.S. EPA (Environmental Protection Agency) 1987. Joint NRC-EPA Guidance on a Conceptual Design
Approach for Commercial Mixed Low-Level Radioactive and Hazardous Waste Disposal
Facilities - Action Memorandum. U.S. EPA, Washington, D.C, August 18, 1987. URL:
nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=100018ZA.txt.
Interrogatory 09/01A: UAC R313-25-7; UAC R313-25-8; UAC R317-6-1 (6)6.1: Water Balance Design Control Features in Cover System Page 25 of 25
DENISON MINES (USA) CORP.
RESPONSES TO INTERROGATORIES -
ROUND 1 FOR RECLAMATION PLAN,
REVISION 4.0, NOVEMBER 2009;
DECEMBER 2011
TABLE OF CONTENTS
Interrogatory 01/01
Interrogatory 02/01
Interrogatory 03/01:
Interrogatory 04/01:
Interrogatory 05/01:
Interrogatory 06/01:
Interrogatory 07/01:
Interrogatory 08/01
10 CFR Part 40, Appendix A, Criterion 6(7); UAC R313-24-
3; Environmental Analysis - Long Term Impacts
10CFR40 Appendix A, Criterion 1: Permanent Isolation
without Ongoing Maintenance
10CFR40, Appendix A, Criterion 4: Location and Design
Requirements
10CFR40, Appendix A, Criterion 6(1): Cover and Closure
at End of Milling Operations
10 CFR PART 40, Appendix A; UAC R317-3-1; and UAC
R317-3: Construction Quality Control and Assurance
10CFR40, Appendix A, Criterion 9: Financial Surety
Arrangements
11E.(2); 10CFR40, Appendix A, Criterion 6(2); 6(3); 6(4):
Verify Effectiveness of Final Radon Barrier, and Phased
Emplacement of Final Radon Barrier, and Report Radon
Barrier Effectiveness
UAC R313-15-101; Radiation Safety Controls and
Monitoring
INTERROGATORY WHITE MESA RECPLAN 01/01:10 CFR PART 40, APPENDIX A,
CRITERION 6(7); UAC R313-24-3; ENVIRONMENTAL ANALYSIS - LONG TERM IMPACTS
REGULA TOR Y BASIS:
UAC R313-24-3:
(1) Each new license application, renewal or major amendment shall contain an environmental report
describing the proposed action, a statement of its purposes, and the environment affected. The environmental
report shall present a discussion of the following:
"(a) An assessment of the radiological and nonradiological impacts to the public health from the
activities to be conducted pursuant to the license or amendment;...
(d) Consideration of the long-term impacts including decommissioning, decontamination, and
reclamation impacts, associated with activities to be conducted pursuant to the license or
amendment... "
UAC R313-24-4 invokes the following requirement from 10CFR40. Appendix A, Criterion 6(7): "The
licensee shall also address the nonradiological hazards associated with the wastes in planning and
implementing closure. The licensee shall ensure that disposal areas are closed in a manner that
minimizes the need for further maintenance. To the extent necessary to prevent threats to human health
and the environment, the licensee shall control, minimize, or eliminate post-closure escape of
nonradiological hazardous constituents, leachate, contaminated rainwater, or waste decomposition
products to the ground or surface waters or to the atmosphere. "
INTERROG A TOR Y STA TEMENT:
Refer to Sections 2.2 and 3 of the Reclamation Plan, Rev. 4.0:
1. Handling and Disposal ofAsbestos-Containing Material, if Present: Please identify the
characteristics, nature of occurrence, and quantity(ies) of any asbestos-containing materials (ACM),
such as friable asbestos or other ACM, transit pipe, etc., that could be encountered during
reclamation/decommissioning activities.
If ACM are known or suspected to be encountered during decommissioning, please prepare and
submit an Asbestos Characterization, Removal, Handling and Disposal Plan for implementation
prior to and/or during site demolition and site reclamation activities. Indicate regulatory criteria and
statutes applicable to such materials. Provide information on, and the location of records important
to decommissioning procedures for any ACM, as applicable, for protection of health and safety.
Provide procedures for demonstrating that asbestos handling and disposal activities and practices
will be completed in accordance with all applicable state and Federal requirements, including, but
not limited to (1) Utah Solid and Hazardous Waste Control Board, Utah Solid Waste Permitting and
Management Rules (Utah Division of Solid and Hazardous Waste 2009, or latest version); and (2)
Utah Air Quality Rules (Utah Division of Air Quality 2010, or latest version).
Response No. 1:
An initial site survey to determine the amount of sampling and characterization required
for a facility-wide asbestos inspection has been completed in September of 2011. The
facility-wide inspection to determine the presence of asbestos in building materials in the
milling facility will be conducted for Denison in the spring of 2012. The investigation will
Inten-ogatory 01/01:10 CFR PART 40, Appendix A. Criterion 6(7); UAC R313-24-3; Environmental Analysis - Long Temn Impacts Page 1 of 44
identify buildings and facilities where no suspect materials are identified, or sampled
materials did not test positive for asbestos-containing materials. A detailed asbestos
survey will be conducted, if and as necessary, on a building-by-building basis to confirm
identification of building materials and outline methods of asbestos containment,
handling, and disposal. An inspection report will be prepared after the facility-wide
inspection. The report will be submitted to the DRC as a standalone document. This
report and any other future Denison records pertinent to decommissioning procedures
for asbestos-containing materials, as applicable, for protection of health and safety will
be stored on-site at the Safety Office. After decommissioning activities are complete and
prior to the site being turned over to the Department of Energy (DOE), pertinent records
will be stored on-site in a temporary storage facility or at the Denison office in Denver,
Colorado.
2. Handling and Disposal of (Other) Nonradiological Hazardous Constituents Present: Please
identify the characteristics, nature of occurrence, and quantity(ies) of other non-radiological
hazardous constituents present at the Mill Site that would be encountered during
reclamation/decommissioning activities. Include information on acid leach solutions (e.g., associated
with the seven acid leach tanks inside the Main Mill building) and solvent extraction (SX) reagents
(see Reclamation Plan, Sections 2.2.2 and 3.1), and other non-radiological and potential hazardous
constituents present. Please prepare and submit procedures for characterizing, handling, and
treating and/or disposing of such non-radiological hazardous constituents prior to and/or during site
demolition and site reclamation activities. Indicate regulatory criteria and statutes applicable to such
materials. Provide information on, and the location of records important to decommissioning
procedures for any such materials, as applicable, for protection of health and safety. Provide
procedures for demonstrating that handling and disposal activities and practices associated with the
management of these constituents will be completed in accordance with all applicable state and
federal requirements.
Response No. 2:
Discussion of handling and disposal of other non-radiological hazardous constituents at
the mill site is provided in the Preliminary Mill Decommissioning Plan (MWH, 2011b).
This plan was submitted to the Executive Secretary as Appendix G of the 2011
Reclamation Plan for the White Mesa Mill (Denison (2011) on September 30, 2011.
As stated in MWH (2011b), all mill decommissioning work shall conform to applicable
Federal, State, and County environmental and safety regulations. The work shall also
conform to applicable conditions in the Radioactive Materials License with the Utah
DRC. Safety practices, procedures, and monitoring shall be conducted as specified by
the Mine Safety and Health Administration (MSHA) and the current Denison health and
safety procedures in place, as well as the Denison Radiation Safety Program for
Reclamation (submitted to the Executive Secretary as Attachment D of the 2011
Reclamation Plan).
Denison records pertinent to decommissioning procedures for protection of health and
safety will be stored on-site at the Safety Office. After decommissioning activities are
complete and prior to the site being turned over to the Department of Energy (DOE),
pertinent records will be stored on-site in a temporary storage facility or at the Denison
office in Denver, Colorado.
Inten-ogatory 01/01:10 CFR PART 40, Appendix A, Criterion 6(7); UAC R313-24-3; Environmental Analysis - Long Tenn impacts Page 2 of 44
BASIS FOR INTERROGATORY:
Facility-related hazardous chemicals and reagents are present in one or more stmctures at the White
Mesa Mill Site. ACM might also be present in one or more stmctures at the Mill Site. Such materials
should be handled and disposed of in strict accordance with applicable state and federal requirements, in
order to minimize potential impacts to workers and public health and the environment. Additional
information needs to be fumished regarding the location of records important to decommissioning
procedures for any non-radiological hazardous constituents, and ACM, as applicable, for ensuring
protection of health and safety. All work related to characterization, removal, handling and disposal of
such materials should be conducted in accordance with applicable federal, state, and local air quality
and solid waste disposal mles, regulations and guidelines.
NUREG-1620 (NRC 2003), Section 5.2.3, indicates that the decommissioning plan will be acceptable if it
meets the following criteria:
"... (7) The plan indicates the location of records important to decommissioning procedures for
protection of health and safety and demonstrates that decommissioning will be completed as soon
as practicable, as required by 10 CFR 40.42 and Appendix A, Criterion 6A..."
" ...9) The plan adequately describes the control of non-radiological hazards associated with the
wastes as required by 10 CFR Part 40, Appendix A, Criterion 6(7). "
NRC Draft Guidance (DG) 3024 (NRC 2008), Section 8.1 specifies that license applicants should provide
the following with respect to reclamation/decommissioning projects:
"Provide the proposed plan for removing and disposing of stmctures, tanks, and equipment used
in conjunction with the uranium milling operations, including the plan for managing all
hazardous and radioactive materials. In the decommissioning plan, consider approaches for
identifying radiological hazards before initiating dismantlement of stmctures and equipment and
for detection and cleanup of removable contamination from such stmctures and equipment in
order to minimize occupational radiation exposure. Describe appropriate survey methods for
determining the extent of equipment contamination before initiating decontamination work.
Focus, in particular, on those parts of the mill process system that are likely to have accumulated
contamination over long time periods (e.g, pipes, ventilation, equipment, effluent control
systems, and facilities and equipment used in or near the yellowcake dryer area). Describe any
plans for the decontamination of equipment for release for unrestricted use... "
REFERENCES:
NRC (U.S. Nuclear Regulatory Commission). 2003. Standard Review Plan for the Review of a
Reclamation Plan for Mill Tailings Sites under Title II of the Uranium Mill Tailings Radiation
Control Act of1978. Washington DC, June 2003.
NRC 2008. Standard Format and Content of License Applications for Conventional Uranium Mills, Draft
Regulatory Guide DG-3024, May, 2008.
Utah Division of Air Quality. 2010. Utah Air Quality Rules. Effective June 3, 2010.
URL: http://www. airquality. Utah.gov/Planning/Rules/Actual_Rules/current-mles.pdf.
Utah Division of Solid and Hazardous Waste. 2009. Utah Solid And Hazardous Waste Control Board,
Utah Solid Waste Permitting and Management Rules Utah Administrative Code (R315-301
Through 320). Revised as of May 15, 2009. URL:
http://www.hazardouswaste.utah.gov/Rules/Adobe/SWRules/R315-301-320eff.pdf.
Interrogatory 01/01; 10 CFR PART 40, Appendix A, Criterion 6(7); UAC R313-24-3; Environmentai Analysis - Long Temi Impacts Page 3 of 44
INTERROGATORY WHITE MESA RECPLAN 02/01: 10CFR40 APPENDIX A, CRITERION 1:
PERMANENT ISOLATION WITHOUT ONGOING MAINTENANCE
REGULA TOR Y BASIS:
UAC R313-24-4 invokes the followins requirement from 10CFR40 Appendix A. Criterion 1: "The general
goal or broad objective in siting and design decisions is permanent isolation of tailings and associated
contaminants by minimizing disturbance and dispersion by natural forces, and to do so without ongoing
maintenance. For practical reasons, speciflc siting decisions and design standards must involve flnite
times (e.g., the longevity design standard in Criterion 6). The following site features which will contribute
to such a goal or objective must be considered in selecting among altemative tailings disposal sites or
judging the adequacy of existing tailings sites:
• Remoteness from populated areas;
• Hydrologic and other natural conditions as they contribute to continued immobilization and
isolation of contaminants from ground-water sources; and
• Potential for minimizing erosion, disturbance, and dispersion by natural forces over the long
term.
The site selection process must be an optimization to the maximum extent reasonably achievable in terms
of these features.
In the selection of disposal sites, primary emphasis must be given to isolation of tailings or wastes, a
matter having long-term impacts, as opposed to consideration only of short-term convenience or benefits,
such as minimization of transportation or land acquisition costs. While isolation of tailings will be a
function of both site and engineering design, overriding consideration must be given to siting features
given the long-term nature of the tailings hazards.
Tailings should be disposed of in a manner that no active maintenance is required to preserve conditions
of the site."
INTERROG A TOR Y STA TEMENT:
1. Refer to Section 3.3.7 of the Reclamation Plan:
a. Please evaluate and report the potential for long-term plant intrusion and animal intmsion
into the cover system that could impact the performance of the flnal cover system, including
the compacted radon barrier layer and buried tailings, assuming minimal to no long-term
maintenance following decommissioning.
b. Please provide a description of plant root characteristics (e.g., root depths, root
distribution, leaf area index) ofplant species that are currently present or could be
expected to be present in the future at the site
c. Please describe and estimate the range of burrowing depths and burrow densities for
animal species that presently frequent or could be expected to frequent the site or the site
vicinity
d. Please provide information on the required characteristics of a biobarrier layer, such as a
cobble layer (e.g., required particle size distribution and minimum required thickness); and
the need for, and design requirements relating to any adjacent fliter layer(s) that would be
incorporated into the flnal cover system to minimize or prevent potential burrowing
animals and root growth from penetrating the cover, including the radon barrier layer
inten-ogatory 02/01:10CFR40 Appendix A, Criterion 1: Pemianent Isolation without Ongoing Maintenance Page 4 of 44
and/or buried cell tailings. Include information justifying that the flnal specified
characteristics of the biobarrier layer would be adequate to deter long-term biointmsion
into the radon barrier layer, considering available published information on biontmsion
cases studies (e.g. Hakonson 1986; Cline et al. 1980, etc.). Alternatively, provide detailed
information that clearly demonstrates why such a biobarrier is not warranted or necessary:
Response 1:
This interrogatory references the cover design presented in the Denison's 2009
Reclamation Plan. Denison has proposed an evapotranspiration (ET) cover for
reclamation of the tailings cells. The updated design is presented in the 2011
Reclamation Plan submitted to the Executive Secretary on September 30, 2011. The
response to the comments in this interrogatory is applicable to the updated cover design.
Information on the evaluation of long-term plant and animal intrusion, description of plant
root characteristics, and evaluation of a biobarrier for the ET cover is provided in
Appendix D of the Updated Tailings Cover Design Report (submitted to the Executive
Secretary as Appendix D of the 2011 Reclamation Plan).
BASIS FOR INTERROG A TORY:
Burrowing animals have the potential to penetrate the cover system and disturb the waste tailings of a
cell. The burrowing animal could disturb the cover system resulting in "channels for movement of water,
vapors, roots, and other ammals " EPA, Draft Technical Guidance for RCRA/CERCLA Final Covers,
April 2004 [EPA 2004]). The extent of damage caused by animal burrowing depends on the animals
burrowing depth ability. Mammals such as the badger and deer mouse have been reported to depths of
150-230 cm [4.9 to 7.5 ft] (Anderson and Johns 1977, Gano and States 1982, Cline, et al 1982 and
Lindzey 1976) and 50 cm [1.6 ft], respectively (Reynolds and Laundre 1988 and Reynolds and Wakkinen
1987, and Smith, et al 1997). Moisture content and physical features of the soil can affect burrowing
potential (Reichman and Smith 1990). Maximum burrowing depths for animals at or near the site should
be identifled and appropriate measures taken to protect the cover system, especially the radon barrier
layer, from potential long-term damage/dismption by burrowing animals.
Plants growing into the cover could root into the radon barrier layer and/or into tailings. Penetrating
roots could provide channels for water movement and may cause shrinking or cracking of clay layers
(Reynolds 1990). At arid and semi-arid sites, root densities can be higher in buried clays and plant roots
may concentrate in and extract water from buried clays and plant roots may concentrated in and extract
water from buried clay layers, causing some seasonal desiccation (Hakonson 1986 and Reynolds 1990a).
The degree of root penetration depends on the rooting depth of the plants present at the site or in the site
vicinity and the ability of the plant roots to penetrate the soil.
Hakonson(l986) found that a biotic barrier of 28 inches composed of cobbles (of diameter to inches)
overlain by 12 inches of gravel was an effective deterrent to burrowing by gophers and mice and that the
large void spaces between the cobbles deterred plant root development. Cline et al (1980) and Cline
(1979) found a layer of cobblestone to be effective in limiting rodent and insect penetration. Final
selection ofthe minimum layer thickness and rock sizing in the biobarrier should be based on site-speciflc
conditions and characteristics (e.g., types of animals and plants that are or might be present in the area
over the design life of the closed embankment).
According to the Revision 4 Reclamation Plan (e.g.. Table 1.7-1), community types identifled within the
site boundary include Pinion-juniper Woodland, Big Sagebrush, and Controlled Big Sagebmsh. Different
published references indicate that Big Sagebmsh in the western U.S. can exhibit rooting depths between
Interrogatory 02/01:10CFR40 Appendix A, Criterion 1: Permanent Isolation without Ongoing Maintenance Page 5 of 44
about 114 and 250 cm [between about 3.7 and 8 ft] and possibly up to 914 cm [30 ft] (e.g., see Waugh, et
al 1994; Foxx, et all984; Klepper, et al 1985, Reynolds 1990b). The Reclamation Plan, Rev. 4 also
indicates (Section 1.7.1.2) that badgers, longtail weasels, and several rodents (e.g., deer mouse) exist in
the area.
Interrogatory 02/01:10CFR40 Appendix A, Criterion 1: Pemianent Isolation without Ongoing Maintenance Page 6 of 44
REFERENCES:
Anderson, D. C, and Johns, D. W. 1977. "Predation by Badger on Yellow-Bellied Marmot in Colorado, "
Southwestern Naturalist, Vol 22, pp. 283-284.
Cline, J.F.. 1979. Biobarriers Used in Shallow-Burial Ground Stabilization. Technical Report.. Pacific
Northwest Laboratory PNL-2918. March 1, 1979.
Cline, J F., K. A. Gano, and L. E. Rogers, 1980, "Loose Rock as Biobarriers in Shallow Land Burial, "
Health Physics, Vol 39, pp. 494-504.
Cline, J. F., F.G. Burton, D. A. Cataldo, W. E. Skiens, andK. A. Gano. 1982. Long-Term Biobarriers to
Plant and Animal Intrusion of Uranium Tailings, DOE/UMT-0209, Pacific Northwest
Laboratory, Richland, Washington.
EPA (U.S. Environmental Protection Agency). 2004. (Draft) Technical Guidance for RCRA/CERCLA
Final Covers. USEPA 540-R-04-007, OSWER 9283.1-26. April 2004, 421 pp. URL:
nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=P10074PP.txt.
Foxx, T.S., G.D. Tiemey, and J.M. Williams., 1984. Rooting Depths of Plants Relative to Biological and
Environmental Factors, Los Alamos Report LA-10254-MS, November 1984.
Hakonson, T.E. 1986. Evaluation of Geologic Materials to Limit Biological Intmsion into Low-Level
Radioactive Waste Disposal Sites. LA-10286-MS. Los Alamos National Laboratory, Los Alamos,
New Mexico.
Klepper, E. L., K. A. Gano, andL. L. Cadwell. 1985. Rooting Depth and Distributions of Deep-Rooted
Plants in the 200 Area Control Zone of the Hanford Site, PNL-5247, Battelle Paciflc Northwest
Laboratory, Richland, Washington.
Lindzey, F. G. 1976. "Characteristics of the Natal Den of the Badger, " Northwest Science, Vol 50, No. 3,
pp. 178-180.
Reichman, O.J., and Smith, S. C. 1990. "Burrows and Burrowing Behavior by Mammals," pp. 197-244 in
H.H. Genoways, ed.. Current Mammology. Plenum Press, New York and London. 1990.
Reynolds, T. D. andJ. W. Laundre, 1988. "Vertical Distribution of Soil Removed by Four Species of
Burrowing Rodents in Disturbed and Undisturbed Soils," Health Physics, Vol 54, No. 4, pp.
445-450.
Reynolds, T. D. and W. L. Wakkinen, 1987. "Burrow Characteristics of Four Species of Rodents in
Undisturbed Soils in Southeastern Idaho, " American Midland Naturalist, Vol 118, pp. 245-260.
Reynolds, TD. 1990a. "Effectiveness of Three Natural Biobarriers in Reducing Root Intmsion by Four
Semi-Arid Plant Species ", Health Physics, Vol 59, pp. 849-852.
Reynolds, T. D, 1990b. "Root Mass and Vertical Root Distribution of Five Semiarid Plant Species, "
Health Physics, Vol 58, No. 2, pp. 191-197.
Smith, E.D., Luxmoore, R.J, and Suter, G.W. 1997. "Natural Physical and Chemical Processes
Compromise the Long-Term Performance of Compacted Soil Caps, " in Barrier Technologies for
Environmental Management - Summary of a Workshop. National Research Council, National
Academy Press, Washington, DC, pp. D-61 to D-70.
Waugh, W. J., JC. Charters, G. V. Last, B. N. Bjornstad, S. O. Link, C. R. Hunter, 1994. Barrier
Analogs: Long-Term Performance Issues, Preliminary Studies, and Recommendations, PNL-9004,
Paciflc Northwest Laboratories, Richland, Washington.
Inten-ogatory 02/01:10CFR40 Appendix A, Criterion 1: Pemianent Isolation without Ongoing Maintenance Page 7 of 44
INTERROGATORY WHITE MESA RECPLAN 03/01: 10CFR40, APPENDIX A, CRITERION 4:
LOCATION AND DESIGN REQUIREMENTS
REGULA TORY BASIS:
UAC R313-24-4 invokes the following requirement from 10CFR40, Appendix A, Criterion 4: "The following
site and design criteria must be adhered to whether tailings or wastes are disposed of above or below
grade.
(a) Upstream rainfall catchment areas must be minimized to decrease erosion potential and the size ofthe
floods which could erode or wash out sections of the tailings disposal area.
(b) Topographic features should provide good wind protection.
(c) Embankment and cover slopes must be relatively flat after flnal stabilization to minimize erosion
potential and to provide conservative factors of safety assuring long-term stability. The broad objective
should be to contour flnal slopes to grades which are as close as possible to those which would be
provided if tailings were disposed of below grade; this could, for example, lead to slopes of about 10
horizontal to 1 vertical (10h:lv) or less steep. In general, slopes should not be steeper than about 5h:lv.
Where steeper slopes are proposed, reasons why a slope less steep than 5h:lv would be impracticable
should be provided, and compensating factors and conditions which make such slopes acceptable should
be identifled.
(d) A full self-sustaining vegetative cover must be established or rock cover employed to reduce wind and
water erosion to negligible levels.
Where a full vegetative cover is not likely to be self-sustaining due to climatic or other conditions, such as
in semi-arid and arid regions, rock cover must be employed on slopes of the impoundment system. The
Executive Secretary will consider relaxing this requirement for extremely gentle slopes such as those
which may exist on the top of the pile.
The following factors must be considered in establishing the flnal rock cover design to avoid
displacement of rock particles by human and animal traffic or by natural process, and to preclude
undercutting and piping:
• Shape, size, composition, and gradation of rock particles (excepting bedding material
average particles size must be at least cobble size or greater);
• Rock cover thickness and zoning of particles by size; and
• Steepness of underlying slopes.
Individual rock fragments must be dense, sound, and resistant to abrasion, and must be free from cracks,
seams, and other defects that would tend to unduly increase their destmction by water and frost actions.
Weak, friable, or laminated aggregate may not be used.
Rock covering of slopes may be unnecessary where top covers are very thick (or less); bulk cover
materials have inherently favorable erosion resistance characteristics; and, there is negligible drainage
catchment area upstream of the pile and good wind protection as described in points (a) and (b) ofthis
criterion.
Furthermore, all impoundment surfaces must be contoured to avoid areas of concentrated surface mnoff
or abrupt or sharp changes in slope gradient. In addition to rock cover on slopes, areas toward which
surface mnoff might be directed must be well protected with substantial rock cover (rip rap). In addition
to providing for stability of the impoundment system itself, overall stability, erosion potential, and
geomorphology of surrounding terrain must be evaluated to assure that there are not ongoing or
potential processes, such as gully erosion, which would lead to impoundment instability.
Inten-ogatory 03/01:10CFR40, Appendix A, Criterion 4: Location and Design Requirements Page 8 of 44
(e) The impoundment may not be located near a capable fault that could cause a maximum credible
earthquake larger than that which the impoundment could reasonably be expected to withstand. As used
in this criterion, the term "capable fault" has the same meaning as deflned in section 111(g) of Appendix A
of 10 CFR Part 100. The term "maximum credible earthquake" means that earthquake which would cause
the maximum vibratory ground motion based upon an evaluation of earthquake potential considering the
regional and local geology and seismology and speciflc characteristics of local subsurface material.
(f) The impoundment, where feasible, should be desired to incorporate features which will promote
deposition. For example, design features which promote deposition of sediment suspended in any mnoff
which flows into the impoundment area might be utilized; the object of such a design feature would be to
enhance the thickness of cover over time. "
INTERROGATORY STATEMENT:
1. Soil Cover-Plant and Animal Intrusion (Refer to Reclamation Plan, Rev. 4.0, Section 3.3):
a. Please provide information on the design and required characteristics of a biobarrier
system required in the flnal cover system to prevent long-term intmsion into the radon
barrier layer by burrowing animals or plants after closure, in accordance with
Interrogatory Item No. 1 under Interrogatory WhiteMesa RecPlan 02/01: 10CFR40
Appendix A, Criterion 1: "Permanent Isolation without Ongoing Maintenance" above.
Response Nol:
See Response 1 to Interrogatory 02/01. A biobarrier is not included in the cover design.
Information on evaluation of the need for a biobarrier for the ET cover is provided in
Appendix D of the Updated Tailings Cover Design Report.
2. Tailings and Evaporation Cells (Refer to Sections 3.2.2.1, 3.2.2.3, 3.2.2.4, and 3.2.2.5 and
Figure 5.1-1 in Attachment A of the Reclamation Plan, Rev. 4.0):
a. Please revise (steepen) the slope of the top deck portion of the flnal cover system to ensure
that an adequate factor of safety is provided to ensure long-term stability ofthe completed
embankment(s) considering the potential for future slope reversal(s) due to long-term
differential settlement or subsidence, in accordance with guidance contained in lOCFR 40,
Appendix A, Technical Criterion 4; to be consistent with published recommended ranges of
slopes for final cover systems for uranium mill tailings repositories, surface impoundments,
and landfills - i.e., approximately 2% to 5% (e.g, see DOE 1989; EPA 1989; EPA 1991,
ITRC 2003, and EPA 2004); and to ensure that the topslope portion of the embankment
surface will exhibit a slope across the entire embankment; after settlement/subsidence, that
is adequate to promote lateral mnoff ofprecipitation without ponding.
Response No 2:
The current design for the proposed cover system has top surface slopes ranging from
0.5 to 1 percent. Covers with similar "top deck" slopes have been constructed for
Uranium Mill Tailings Radiation Control Act (UMTRCA) Title I and II sites including;
Falls City Title I site in Texas (less than 1 % cover slopes);
Bluewater Title II site in New Mexico (0.5 - 4% cover slopes);
Conquista Title li site in Texas (0.5 - 1% cover slopes);
inten-ogatory 03/01:10CFR40, Appendix A, Criterion 4: Location and Design Requirements Page 9 of 44
• Highland Title II site in Wyoming (0.5 - 2% cover slopes);
• Panna Maria Title ii site in Texas (0.5% cover slopes);
• Ray Point Title 11 site in Texas (0.5 - 1 % cover slopes); and
• Shenvood Titie li site in Washington (0.25% cover slopes).
Settlement analyses for the proposed cover design are provided in Appendix F of the
Updated Tailings Cover Design Report. Settlement of the thickest profile of tailings in
Cells 2, 3, and 4A and 4B is anticipated to range from 2 to 10 inches after placement
of interim cover and dewatering. Settlement monuments currentiy exist in Cell 2 and
the eastern portion of Ceil 3 where interim cover has been placed. For the remainder
of Cell 3, and for Cells 4A and 4B, settlement monuments will be installed after
placement of interim cover. These monuments will be monitored on a regular basis in
order to verify that 90 percent of the settlement due to dewatering and interim cover
placement has occurred prior to construction of the final cover. Additional fill, if
necessary, will be placed in any low areas in order to maintain positive drainage of the
cover surface. Additional settlement due to the construction of the final cover is
estimated to be on the order of 5 to 6 inches. The estimated amount of additional
settlement is sufficiently low such that ponding is not expected with cover slopes of 0.5
to 1 percent.
3. Mill Decommissioning (Refer to Section 3.2.3.1 and Sections 4.0 through 4.3 of Attachment A
of the Reclamation Plan, Rev. 4.0):
a. Please specify a maximum allowable void space percentage that will be allowed when
disposing of demolition and decommissioning debris and mbble in tailings cells. Describe
construction practices that will enable satisfying this specified limit.
b. Please provide additional information on speciflc procedures that will be used for
placement, backfilling, and compaction of debris and mbble generated by demolition and
decommissioning activities. Address differences necessary to ensure specifled limits are
achieved for metallic stmctural components, pipe and pipe sections, wood debris, concrete
mbble, and large rock fragments within the embankment Describe in detail methods that
will be used to reduce the size of debris and mbble items before being blended with tailings
or contaminated soils. Describe procedures for compacting each type of debris or mbble
mixed with tailings or contaminated soil Include maximum allowable lift thickness and
maximum allowable dimensions for each type of debris or mbble to be disposed of.
c. Please include speciflcations, constraints, and procedures for constmcting the final waste
layer upon which the cover system (final closure cap) will be constructed. Demonstrate that
these speciflcations, constraints, and procedures are adequate to preserve the integrity and
stability of the cover system.
d. Please deflne the characteristics and volumes of organic materials (including, for example,
wood, branches, roots, paper, and plastic), if any, that might be disposed of Provide
speciflcations and procedures for disposing of organic materials such that long-term
biodegradation of the disposed organic materials will not compromise the integrity and
stability of the cover system.
e. Please provide detailed procedures that will be used to control residual voids to meet the
specifled maximum allowable void space percentage(s) and a description of constmction
intenrogatory 03/01:10CFR40, Appendix A, Criterion 4: Location and Design Requirements Page 10 of 44
quality assurance / quality control and veriflcation procedures to be used to demonstrate
that the void space criteria are achieved.
f Please provide an Asbestos Characterization, Removal, Handling and Disposal Plan for
implementation prior to and/or during site demolition and site reclamation activities for
any ACM (e.g., friable, transit pipe) that may be encountered during reclamation activities
(see also Interrogatory WhiteMesa RecPlan 01/01 above).
Response No 3:
Procedures for placement and compaction of demolition and decommissioning debris,
specifications for constructing the final waste layer, and specifications for disposal of
organic materials in the tailings cells is provided in updated Technical Specifications
(Attachment A of the 2011 Reclamation Plan, Denison (2011)). Quality assurance and
quality control procedures for controlling residual voids and minimizing void spaces
during disposal of demolition and decommissioning debris is provided in the
Construction Quality Assurance/Quality Control (CQA/QC) Plan (Attachment B of the
2011 Reclamation Plan, Denison (2011)). A maximum allowable void space percentage
for the placed demolition and decommissioning debris was not specified in the Technical
Specifications due to the difficulties associated with measuring that parameter for quality
controi during construction. The specifications, as outiined, provide a method
specification for proper sizing, placement and compaction of debris, as well as for
placement and compaction of covering fill. These method specifications are derived
from debris placement procedures successfully used for uranium mill demolition and
debris burial on other sites in the western U.S.
See Response 1 to Interrogatory 01/01 regarding a report for characterization, removal,
handling and disposal of asbestos-containing material.
4. Cover Design and Monitoring (Refer to Reclamation Plan, Rev. 4.0, Sections 3.2.2.1 and 3.3
and Section 5.4 of Attachment A):
a. Please describe quantitative acceptance criteria that will be used as the basis for
evaluating stability of the closed tailings cells in terms ofpotential long-term total and
differential settlement or subsidence that might occur within the closed embankments or
tailings cells. Provide information on parameters that could affect the long-term integrity
of the final closure cap and/or could affect long-term infiltration rates through the closed
embankment, including, but not necessarily limited to:
• The potential for (e.g., localized) slope changes and slope reversal in the final cap.
• The potential for cracking of the compacted clay layer (radon barrier layer). Provide
information regarding the relationship of the selected acceptance criteria for assessing
cracking potential in the compacted clay layer (e.g., a specified maximum allowable
tensile stress in clay) to the percent tensile strains in the compacted clay layer and the
range ofplasticity indices for the proposed clay layer source materials (see, for example,
Gilbert and Murphy 1987, Section 4; Daniel 1993, pp. 472-474; Koemer and Daniel
1994) as they relate to and support the final selected cover design. Demonstrate that the
proposed clay layer source materials are suitable for minimizing potential long-term
cracking within the compacted clay layer to within an acceptable level
b. Please provide engineering analyses (including calculations, numerical modeling and
simulations) documenting the projected long-term settlement performance ofthe closed
Interrogatory 03/01:10CFR40, Appendix A, Criterion 4: Location and Design Requirements Page 11 of 44
embankment for various scenarios involving disposal of tailings mixed with demolition
debris and/or rubble deemed reasonably representative of the range of tailings/debris and
mbble disposal configurations that could occur within the embankment Provide numerical
analyses demonstrating settlement performance of the embankment using a software tool
such as the Fast Lagrangian Analysis of Continuum (FLACf') code (Itasca 2009) or other
similar software, as appropriate, or altematively, provide information justifying why such
analyses are not warranted or necessary. Compare and document predicted
settlement/subsidence results against the acceptance criteria identified stated in response
to Item a. above.
Response No 4:
This interrogatory references the multi-layered cover design presented in the Denison's
2009 Reclamation Plan. Denison has since then proposed an evapotranspiration (ET)
cover for reclamation of the tailings ceils which does not include a ciay layer. This
updated design is presented in the 2011 Reclamation Plan. The response to the
comments in this interrogatory address comments pertinent to the updated cover design.
Cover cracking analyses are not applicable for the ET cover design, due to the absence
of a compacted clay layer susceptible to cracking. Settlement and liquefaction analyses
for the ET cover are provided in the Updated Tailings Cover Design Report.
5. Erosion Protection (Refer to Sections 3.2.2.2, 3.3.1, and 3.3.5; Section 6.0 and Figures A.5.1-1
through A-5.1.4 in Attachment A; and Attachment G to the Reclamation Plan, Rev. 4.0):
a. Please provide a clearly described, clearly referenced, up-to-date calculation ofthe
Probable Maximum Precipitation (PMP) Event to be used for final reclamation design
planning. Provide information demonstrating that the PMP Event was determined using
approaches that are consistent with guidelines contained in NUREG-1623 (NRC 2002).
b. Please provide information demonstrating that the riprap sizing proposed for all topslope
and sideslope areas is adequate for the updated PMP Event magnitude.
c. Please update Figures A.5.1-1 through A-5.1.4 in Attachment A to reference and refiect
applicable updated information and updated erosion protection design criteria as
described in this interrogatory item. Please describe and clearly indicate on the
reclamation plan drawings, the location(s), minimum horizontal reach length(s), and
minimum thickness(es) of any toe rock apron(s) to be installed at the toes of any final
closed embankment slopes, including all cells (Cells 1 through 4B). Provide updated
calculations necessary to justify the stone size required to maintain (stabilize) the transition
slope from the embankment sideslopes to surrounding fiatter terrain. Determine and justify
the Dso particle size of rock used in each such toe rock apron, the minimum horizontal
reach, and minimum depth for each such apron for the updated PMP Event and using an
appropriate methods as described in the following reference documents:
• NRC 2002
• NRC 2003 (Section 3)
• Robinson, et al 1998; and
• Apt, et al 2008 (if round-shaped riprap is used in instances where overtopping fiow
could occur).
Inten-ogatory 03/01:10CFR40, Appendix A, Criterion 4: Location and Design Requirements Page 12 of 44
d. Provide information on the shape characteristics of rock (stones) to be used in any rock toe
aprons (e.g., angular vs. rounded stones).
e. Please verify and justify how the minimum horizontal reach (7.0 ft) and the minimum depth
(2.0ft) for the rock apron depicted on Figure A-5.1-4 are adequate, when the
methodologies identified above are considered.
f For any areas adjacent to disposal Cells 1 through 4B where a toe rock apron is not
proposed to be installed, provide information to clearly demonstrate that the absence of
such will not compromise long-term erosion protection of the closed tailings cells.
Response No 5:
Erosional analyses for the ET cover design are provided in the Updated Tailings Cover
Design Report. An updated calculation of the PMP event was used for the analyses.
The required erosion protection is also provided on the Drawings as part of Attachment
A of the 2011 Reclamation Plan.
Rock Quality (Refer to Section 3.3.5 of the Reclamation Plan [Rev. 4.0], and Section 6.0 and
Figure A-5.1-4 of Attachment A and Attachment H to the Reclamation Plan [Rev. 4.0J) [Note:
This interrogatory item was previously provided to DUSA in January 2010 as part ofthe Round 2
Interrogatories submitted on the Cell 4B Environmental Report]:
a. Please include information as appropriate to refiect updated criteria contained in NUREG-
1623 (NRC 2002) regarding acceptability of rock, based on its rock quality score, for use
in areas that the NRC may classify as "frequently saturated areas, " including rock toe
apron areas at the toes of the closed cell outslopes, to be addressed in the final closure
design. Specifically, indicate that rock from the Brown Canyon Site borrow site would be
rejected (based on the NUREG-1623 rock scoring criteria) from use in the rock toe apron
areas at the base of the toes of cell outslopes in the final closure design. Please verify and
provide information to demonstrate that adequate quantities of acceptable rock (based on
the NUREG-1623 guidance) for completing required final reclamation activities at the
White Mesa Mill Site are available from other borrow sources.
Response No 6:
Evaluation of potential rock sources for use as riprap and erosion protection at the site is
included in the Updated Tailings Cover Design Report. Based on the information
provided in NUREG 1623, the Brown Canyon rock source will not be used to construct
the rock toe apron areas at the base of the ceil outslopes. Sufficient quantity of rock is
available for these areas from the other sources identified. Adequate quantities of rock
from all identified sources are sufficient for completing the other final reclamation
activities.
7. Filter Design (Refer to Sections 3.2.2.1, 3.3, 3.3.5; Sections 2.5, 5, and 6 in Attachment A; and
Figures A.5.1-2, through A.5.1-4 in Attachment A of the Reclamation Plan [Rev. 4.0]):
a. Please evaluate/demonstrate the need for incorporating a filter layer/filter blanket or
granular bedding layer(s) (1) in the final cover system; (2) beneath riprap at proposed toe
rock apron locations, at flow transition areas; (3) in diversion ditches/channels; (4) in the
Inten-ogatory 03/01:10CFR40, Appendix A, Criterion 4: Location and Design Requirements Page 13 of 44
Cell 1 area sedimentation basin, and (5) at other potential flow impact areas. Please revise
the Revision 4 Reclamation Plan design document and drawings as required to address the
inclusion ofany such layers demonstrated to be necessary for long-term stability. Provide
calculations conflrming the required gradations for materials used in each such
fllter/bedding layer in accordance with applicable fliter design criteria (e.g., as described
in NUREG-1623). Alternatively, provide detailed information that would clearly justify why
fllter/bedding layers are not required at these locations.
Response No 7:
Evaluation of the need for a filter/bedding layer for the areas listed in this interrogatory is
provided in Appendix G of the Updated Tailings Cover Design Report. The required
erosion protection is also included on the Drawings in Attachment A of the 2011
Reclamation Plan.
8. Discharge Channel and Sedimentation Basin (Refer to the Reclamation Plan, Revision 4.0,
Section 2.5, Attachment A,_and Figure A-2.2.4-1):.
a. Please clearly identify on Figure A-2.2.4-1 the topographic contours for all portions of the
proposed Cell 1 discharge channel and the surrounding terrain, and clearly identify the
slope (s) of the channel sides. Please verify and revise the dimensions ofthe Cell 1
discharge channel shown on the flgure as needed to correspond to dimensions ofthe
channel selected in the flnal design, e.g., consistent with the flnal channel dimensions used
in design calculations for the channel and toe apron (e.g.. Attachment G of the Reclamation
Plan).
b. Please provide detailed information, including a geologic map with cross sections as
appropriate, showing subgrade conditions (e.g., weathered vs. unweathered
soils/colluvium, weathered vs. unweathered bedrock of the Dakota Sandstone (and/or
Mancos Shale), fractured vs. unfractured Dakota (and/or Mancos Shale) bedrock, presence
and distribution of conglomeratic lenses, etc.) that would occur along the entire reach of
the proposed channel (i.e., those that might affect both the channel sideslopes and channel
bottom).
c. Please provide information justifying the discharge channel parameter values used in
calculations of discharge channel flow rates presented in Attachment G of the Reclamation
Plan. Please provide a clearly referenced calculation along with clearly referenced
methods to support the selection of an appropriate Manning 'n' coefficient or range of
Manning 'n' coefficients for the discharge channel subgrade conditions, reflecting the
variability of those conditions, as appropriate, along the channel reach. Please also
provide an engineering analysis and/or other information justifying and supporting the
proposed allowable peak channel velocity of 8-10 fps, assuming bedrock material, when
compared to published recommended (lower) allowable peak velocity ranges for bedrock
materials (e.g.. Nelson, et al 1986). Please also include a clearly referenced calculation of
the PMP-derivedflow rate.
d. Please provide additional information regarding the design of the sedimentation basin and
associated outlet channel, including information assessing design issues that are pertinent
to the design of riprap basin and apron systems (see, for example, U.S. Department of
Transportation - Federal Highway Administration 2006, Chapter 10):
• The need for armoring of the apron at the basin/discharge channel connection;
intenogatory 03/01:10CFR40, Appendix A, Criterion 4: Location and Design Requirements Page 14 of 44
• The estimated depth of scour that would occur in a thick pad of riprap and selection of
the sedimentation basin floor depth based on the scour depth;
• The need to include an energy dissipating pool in the basin/channel system design.
Include dimensions and drawings of the dissipating pool, discharge channel, and apron;
• The minimum D^o and thickness of a riprap layer lining the bottom of the sedimentation
basin;
• Riprap type, rounded rock and/or angular rock. Include minimum speciflcations for the
riprap, including but not limited to: lithology, material type, rock hardness, sodium
absorption ratio, LA abrasion test results, etc. as per the guidelines contained in
NUREG-1623 (NRC 2002).
• Riprap cutoff wall or sloping apron as needed if long-term downstream channel
degradation is anticipated;
• Specify design input/criteria and design procedure used for sizing and selecting
dissipating pool, discharge channel, and apron;
• Other pertinent factors that may relate to the design.
Please also provide information on the need for including one or more fliter layers/filter
blankets within the basin/channel system, in accordance with the guidance presented in
paragraph 2.1.1, Filter Requirements, of Appendix D, Designing Riprap Erosion Protection,
of NUREG-1623 (NRC 2002).
e. Provide revised sedimentation basin and drainage channel drawings as required to
address/resolve the issues identified above in the Reclamation Plan, Rev. 4.0.
f. Please provide the basis for allowing the channel to be constructed of bedrock and not
specifying riprap for the channel.
Response No 8:
Updated hydraulic and erosion protection calculations for the discharge channel and
sedimentation basin are provided in Appendix G of the Updated Tailings Cover Design
Report. Updated grading contours through the sedimentation basin and the channel are
shown on the Drawings in Attachment A of the 2011 Reclamation Plan. The proposed
channel dimensions shown on the Drawings correspond with the updated calculations.
Regarding comment b, additional geotechnical exploration along the channel alignment
would be required to characterize the unweathered sedimentary rock along the channel
reach. Denison intends to collect this information in order to finalize the detailed design
of the channel. Approximate bedrock elevations and typical properties were obtained
from previous site geotechnical evaluations as discussed in the Updated Tailings Cover
Design Report.
Portions of the channel and sedimentation basin will be excavated into unweathered
sedimentary rock. These areas will not be lined with riprap, and the channel will not
require an energy dissipation pool or cutoff wall. The transition from a soii surface to a
bedrock surface within the sedimentation basin will be protected with a rock apron. This
portion of rock apron has been conservatively designed to use the sizing of rock used
along the toe of slope at the base of Cell 2. Requirements for the durability of the apron
rock are included in the Technical Specifications (Attachment A of the 2011 Reclamation
Plan).
Inten-ogatory 03/01:10CFR40, Appendix A, Criterion4: Location and Design Requirements Page 15of44
9. Slope Stability Analysis (Refer to Section 3.3.6 of the Reclamation Plan, Rev. 4.0):
a. Please revise and update the information in Section 3.3.6 to:
• Include and/or clearly reference the updated seismic hazard evaluation (Tetra Tech
2010) that was completed for the White Mesa Mill Site, and describe the effects ofthe
results of that evaluation on slope stability analyses.
• Provide updated static and seismic (e.g., pseudostatic) stability analyses for
appropriately selected (e.g., most critical) slopes for the final cover design once it is
selected for implementation.
Response No 9:
The static and seismic slope stability analyses have been updated to include the revised
cover design and incorporate the most current seismic hazard evaluation (Tetra Tech,
2010). A cross section representing the most critical conditions was used for the
analyses. The results of the analyses are presented in Appendix E of the Updated
Tailings Cover Design Report.
BASIS FOR INTERROGATORY:
It is understood that a new design for a final cover system for the tailings cells is currently in
development and that such a design will be reviewed and approved in accordance with DRC's review of
the Infiltration and Contaminant Transport Modeling (ICTM) study at a future date. Any changes found
necessary as a result of this work may be incorporated in a future version of the Reclamation Plan.
Nonetheless, it is important that the current subject, i.e. the review of this separate final cover system
design, address all issues that could affect its long-term performance. Issues described below under this
interrogatory heading, and described in other interrogatories included in this set of interrogatories, must
also be adequately addressed and included in the revision to the Reclamation Plan, Rev. 4.0 (DUSA
2009a).
The "Basis for Interrogatory" discussion presented under Interrogatory WhiteMesa RecPlan 02/01:
10CFR40 Appendix A, Criterion 1: "Permanent Isolation without Ongoing Maintenance" above, provides
the basis/rationale for inclusion of Interrogatory Item No. 1 in this interrogatory.
The proposed cover slope (minimum of 0.2%) is very flat and likely to be problematic from the standpoint
of potential long-term differential settlement lOCFR 40, Appendix A, Technical Criterion 4(c) specifies
that embankment and cover slopes must be relatively flat after flnal stabilization to minimize erosion and
provide conservative factors of safety assuring long-term stability (emphasis added). Technical guidance
developed for and utilized by the U.S. Department of Energy on the UMTRA Project for design and
constmction of uranium mill tailings repositories included typical repository topslope inclinations of 2 to
3 percent (U.S. DOE 1989, Section 3, Figure 3-3).
Further, minimum technology guidance for flnal cover systems for surface impoundments recommended
by the USEPA (EPA 1989; EPA 1991) consists ofthe following:
"...a top layer..., the surface of which slopes uniformly at least 3 percent but not more than 5
percent, to facilitate mnoff while minimizing erosion, ..."
Additionally, an EPA document published in 2004 (EPA) further discusses this guideline in the following
context:
inten-ogatory 03/01:10CFR40, Appendix A, Criterion 4: Location and Design Requirements Page 16 of 44
"...[In the Draft Technical Guidance for RCRA/CERCLA Final Covers, EPA states that] most
landfill cover system top decks are designed to have a minimum inclination of 2% to 5%, after
accounting for settlement, to promote runoff of surface water. ...However, [EPA states that] in
some cases involving the closure or remediation of existing landfllls, waste piles, or source areas,
flatter slopes may already exist and that the cost to increase the slope inclination by flll
placement or waste excavation may be signiflcant In these cases, slightly flatter inclinations can
be considered ifthe future settlement potential can be demonstrated to be small, if concerns about
localized subsidence can be adequately addressed, and if monitoring and maintenance provisions
exist to repair areas of grade reversal or subsidence... "
The proposed cover slope (minimum of 0.2%) is much flatter than the above recommended ranges of
slope inclinations. The cover design should include a minimum embankment and topslope slope
inclination that is consistent with the above guidelines, to ensure that an adequate factor of safety is
provided to maintain long-term stability of the completed embankment(s), considering the potential for
future slope reversal(s) due to long-term differential settlement or subsidence given the range of potential
tailings and/or tailings and demolition debris disposal conditions for the embankment The flnal topslope
inclination must ensure that the topslope portion of the embankment surface will exhibit a positive slope
across the entire embankment; after settlement/subsidence, that will be adequate to promote lateral
runoff ofprecipitation without ponding, over the long-term.
According to Section 3.2.3.1 of the Reclamation Plan, Rev. 4.0, contaminated equipment, stmctures and
dry waste materials from Mill decommissioning, contaminated soils underlying the Mill areas, and
ancillary contaminated materials "will be disposed of in tailings Cell 3, Cell 4A, or the Cell 1 Tailings
Area. " [Note: Although not explicitly stated in the current Reclamation Plan, it is presumed that it is
DUSA's intent that such items may also be disposed in tailings Cell 4B.] The placement/disposal of
demolition debris materials in the tailings management cell(s) has the potential to create voids within
disposed materials or areas of insufficient compaction. The presence of excessive voids in the flnal
reclaimed waste disposal embankment following waste placement and constmction ofthe flnal closure
cap could lead to unacceptable long-term total or differential settlement in the reclaimed embankment.
Excessive amounts of such settlement could impact the integrity of the flnal closure cap that could
produce localized slope change(s) and/or slope reversal(s) in the flnal slopes of the reclaimed
embankment. A slope reversal would create an opportunity for localized ponding of moisture or water
that could increase inflltration rates through the embankment cap. Different materials derived from the
demolition of on-site buildings and/or other stmctures that are planned for disposal on site beneath the
flnal closure cap may have unique characteristics for unloading, placement, and compaction. Proper
disposal of demolition debris materials requires spreading such debris to allow adequate coverage with
contaminated soil and/or tailings that will allow proper compaction of the soil/tailings around the placed
debris items for support so that there is no reliance on the strength of debris for such support.
In order to provide confidence that the flnal cover system installed over any areas where demolition
debris materials are disposed will remain stable over the design life of the facility, the following
provisions should be assured:
• Speciflc procedures should be provided to deflne the processes that will be used for placing
debris materials to ensure that such placement is conducted deliberately and is carefully
controlled to prevent inclusion of voids within the waste matrix. This will facilitate
compaction of backfill around individual debris pieces.
• Specific procedures should be provided that deflne measures that will be taken for reducing
residual voids between individual pieces of debris. The procedures should ensure that
backfilling and other methods obtain proper compaction throughout the embankment.
Inten-ogatory 03/01:10CFR40, Appendix A, Criterion 4: Location and Design Requirements Page 17 of 44
• Specific procedures should be provided that define the methods for placement of debris
within the embankment to ensure that pieces that could protmde into the final cover system
do not remain in a vertical orientation.
• A specific maximum allowable residual void space percentage within tailings/debris
materials and/or contaminated soil/debris material mixtures in the disposal should be
prescribed.
Detailed procedures should be written that define speciflc methods for decommissioning and demolition
debris disposal that minimize residual void space within the Cell 1 embankment to be used for demolition
disposal, including procedures for spreading the materials uniformly and/or backfilling void spaces, and
that are designed to permit the prescribed maximum allowable void space limit to be achieved. Metal
waste materials should be placed in a tailings layer so that stmctural shapes or other large pieces do not
lie across or on top of each other. A procedure should be developed indicating that metal placement
would be conducted so that any large voids that cannot be fllled with soil or cmshed are minimized.
Additionally, in some cases it may not be possible to reach the void spaces with standard earthwork
placement, backfllling, and compaction methods. The Reclamation Plan should address such cases, by
providing a discussion regarding the need for, and criteria for deciding when to implement another
method or methods for filing the otherwise inaccessible void spaces. Such fllling methods may include
injecting grout, controlled low strength material, or other proposed flowable substance into the voids.
Special handling and disposal procedures for oversized and/or odd-shaped steel materials, including
procedures for placing any such materials to one side and cutting or trimming before positioning for
burial, should be addressed. Oversized or odd-shaped materials include any metal waste that cannot be
placed within the specified lift thickness. A procedure should be developed that indicates that placement
and compaction of wood materials would include, at a minimum, placement ofpieces or stacks of such
materials (e.g., bundles of siding or stacks of wood planks) within a specifled maximum lift thickness. A
procedure should be developed that limits the length and diameter of pipes that may be disposed on site
beneath the flnal closure cover at a specifled minimum depth. It is anticipated that the procedure might
require that all pipe (except transit pipe, if encountered at the site) would be cut into lengths of
approximately 10 feet or less, and pipe larger than 12 inches in diameter would be longitudinally split or
cut, while pipe less than 12 inches in diameter would not require splitting.
A procedure should also be developed that addresses the placement of concrete mbble and larger-sized
rock fragments, including procedures for placement and spreading these items into contaminated soil or
tailings material lifts that do not exceed a specifled maximum thickness (within a specifled tolerance
range), and for compacting the composite soil/tailings and mbble and/or rock layers using a specified
minimum number ofpasses of heavy-tracked constmction equipment. Applicable guidance documents
and/or case studies exist where such speciflc procedures have been successfully used at other tailings
disposal repositories (e.g, DOE 1995; DOE 2000; others) and where excessive amounts of post-closure
settlement have not been observed to occur following application of those procedures (e.g., see DOE
2009a, 2009b, 2009c; 2009d) have not been observed in tailings repositories where such debris
placement, backfilling, and compaction procedures were employed.
Additionally, residual voids might result from biodegradation of any disposed organic matter after final
closure of the disposal cells. Procedures should be provided to define measures that would be used to
limit the amount of organic materials disposed of in any lift of the tailings embankment
Specific, quantitative, acceptance criteria need to be defined for the final cover system design/
performance to serve as a basis for demonstrating the long-term stability ofthe final cover system/closed
embankment with respect to long-term settlement or subsidence. The effects of settlement/subsidence on
the long-term integrity of the embankment cover system through the closed embankment over its design
life need to be evaluated.
Inten-ogatory 03/01:10CFR40, Appendix A, Criterion 4: Location and Design Requirements Page 18of44
Available published information should be used to estimate the maximum amount of strain/maximum
distortion value that could tolerated within the compacted clay radon barrier layer over the design life of
the reclaimed embankment Such a limit should be based on properties (e.g., range of plasticity indices)
of the clay soils proposed for constmcting the radon barrier layer. Engineering analyses should be
provided for various representative disposal configurations involving disposed tailings and demolition
debris/mbble materials to demonstrate that predicted settlement/subsidence magnitudes and locations
will not exceed specified acceptance criteria for strain or distortion value. For example, the potential
exists for a substantial quantity of demolition debris materials to be generated and disposed within the
tailings embankment (e.g., see Sections 3.1 and 3.2 of Attachment A and the Mill Decommissioning
calculations in Attachment C of the Reclamation Plan). Consideration should therefore be given to
conducting numerical model simulations for estimating long-term settlement/subsidence performance for
a suite of different representative assumed tailings/debris disposal configurations.
Information needs to be provided to confirm that the proposed clay layer source materials are suitable
for minimizing the potential for long-term cracking of the compacted clay layer or radon barrier (e.g., for
the range of allowable plasticity indices specified in the final cover design). Information also needs to be
provided to demonstrate that the expected range of tailings and debris disposal configurations would not
result in excessive amounts of differential settlement/distortion in the compacted clay radon barrier that
could lead to cracking of that layer or slope reversal(s) in the final cover system surface. This
information, together with engineering analyses ( calculations, numerical model simulations, etc.) of
predicted long-term differential settlement/subsidence within the closed embankment, and consideration
of other specified design criteria (e.g., ponding of water not allowed to occur on the final cover surface as
a result of long-term differential settlement or subsidence) must demonstrate the long-term stability ofthe
closed embankment.
From the information provided in Section 3.2.2.2 and Attachment G of the Reclamation Plan Rev. 4.0
regarding the PMP Event it is unclear whether the method used to calculate the PMP Event is consistent
with guidance issued by the NRC after the information presented in Attachment G was developed (e.g.,
NRC 2002). Attachment G contains an excerpt from a 1998 document which references a 1990
Hydrologic Design Report as the source of the determined 6-hour storm rainfall event. A more recent
PMP Event Computation (DUSA 2009b) supercedes the 1990 PMP calculation and should be referenced.
Information needs to be provided that demonstrates that the proposed riprap sizing for all topslope and
sideslope areas is adequate for the updated PMP Event.
The potential for long-term erosion (sheet and gully) should be adequately mitigated through the use of
riprap and rock mulch in transition and/or channel areas surrounding the reclaimed disposal cells and
across the surface of the final reclamation cover system(s). Rock toe aprons may need to be placed at the
base of sloped embankments to:
• Stabilize and/or anchor any rock placed on the sideslope
• Provide toe drainage channel, to provide for energy dissipation
• Provide erosion protection at the toe of the embankment
• Allow transitioning offlow from the sideslope to the adjacent ground surface
• Provide protection long-term gully intmsion protection.
Published guidance documents (e.g., NRC 2002; Robinson, et al. 1998; Apt, et. al. 2008) provide
updated methodologies for determining the median stone size required to resist stone movement at the
transition of the toe of a slope and provide updated empirical data and recommendations regarding the
minimum depth and minimum horizontal reach of toe rock aprons at the toes ofa stabilized riprap slope.
For example, based on rock chute tests, as referenced in NRC (2002), Robinson et al (1998) provided a
Interrogatory 03/01:10CFR40, Appendix A, Criterion 4: Location and Design Requirements Page 19 of 44
recommendation that the horizontal reach (horizontal width) for rock toe aprons be a minimum of 15
times the D50 of the rock in a rock apron.
Guidance contained in Section 7.2 of Appendix D of NUREG-1623 (NRC 2002, issued after the NRC's
review ofthe Revision 3.0 of the Reclamation Plan), indicates that rock with aggregated rock quality
score of less than 65% should be rejected for use in (critical) areas that are frequently saturated areas
since such rock is generally more vulnerable to weathering than occasionally saturated areas where
freeze/thaw and wet/dry cycles occur less frequently,. According to information presented in Attachment
H to the Reclamation Plan (Revision 4.0), rock tested from the Brown Canyon Site borrow site have rock
quality scores less than 65% and so would be rejected from use in the rock toe apron areas at the base of
the toes of cell outslopes in the final closure design (Section 3.3.5 of Reclamation Plan, Revision 4.0; and
Section 6.0 and Figure A-5.1-4 of Attachment A to that Reclamation Plan). The Reclamation Plan and
Plans and Speciflcations for Reclamation do not present this information/finding, and are therefore
lacking. Implementing the flnal closure design, if found acceptable, depends on availability of adequate
quantities of suitable materials. Should insufficient quantities of suitably acceptable rock for use in
frequently saturated areas be reasonably and practically available, the viability of the flnal closure
design for these components ofthe final closure design would be called into question. Demonstration
must be provided that adequate rock quality and quantities are reasonably and practically available.
NUREG-1623 (e.g., see Appendix D, "Designing Riprap Erosion Protection, "paragraph 2.1.1, Filter
Requirements), recommends that a filter or bedding layer comprised of well-graded rock material be
placed on the cover or in locations where rock riprap is to be placed for erosion protection. Locations
where filter s are recommended include impoundment side slopes, toes of slopes, transition areas,
diversion ditches and channels, stilling areas, and fiow impact areas. As described in NUREG-1623, such
a filter should be designed to bed the riprap and prevent stone penetration into the cover, prevent soil
erosion from flow at the stone/soil interface, and prevent the pooling of precipitation and/or tributary
mnoff from infiltrating into the cover and waste materials. Acceptable fliter sizing criteria for preventing
migration ofthe selected fllter/bedding materials into the riprap and for minimizing or preventing erosion
ofthe soil layer below the fllter/bedding layer are described in NUREG/CR-4620 (Nelson, et al 1986).
Currently, no fliter blankets or bedding layers are shown or specifled in the Reclamation Plan (Rev. 4.0)
in any ofthe areas described in NUREG-1623 where fllters are generally recommended as discussed
above. A demonstration of long-term layer stability is needed to justify the omission of a fllter/bedding
blanket in the final cover system and in the other areas mentioned.
The dimensions shown for the Cell 1 discharge on Figure A-2.2.4-1 in Attachment A of the Reclamation
Plan (Rev. 4.0) are not consistent with the channel dimensions of the proposed channel as indicated in the
channel and toe apron design calculations presented in Attachment G of the Reclamation Plan (Rev. 4.0).
These inconsistencies must be resolved.
The Sedimentation Basin Detail figure provided as Figure A-2.2.4-1 in Attachment A of the Reclamation
Plan (Rev. 4.0) lacks clearly labeled contours and grading along the length and sides of the proposed
Cell 1 drainage ditch. NRC Regulatory Guide (RG) 3.8 (NRC 1992), Section 2.1 requires that license
applicants describe any plans for site modiflcations, and provide a contour map of the site with elevation
contours ofan interval suitable to show signiflcant variations of the site environs and drainage gradients.
Section 3.1 ofRG 3.8 specifles that a map of the site area should be included that clearly depicts contours
and shows a scale that will permit the measurement of distances with reasonable accuracy. This required
information need to be provided.
NUREG-1620 (NRC 2003), Section 3.1.3, also specifles that the hydrologic description of the site will
(only) be considered acceptable if:
"(1) The description of stmctures, facilities, and erosion protection designs is sufficiently
complete to allow independent evaluation of the impact offlooding and intense rainfall
inten-ogatory 03/01:10CFR40, Appendix A, Criterion 4: Location and Design Requirements Page 20 of 44
(2) Site topographic maps are of good quality and of sufficient scale to allow independent
analysis of pre- and post-constmction drainage pattems.
(3) The reclamation plan contains sufficient information for the staff to independently evaluate
the hydraulic designs presented. In general, detailed information is needed for each method that
is used to determine the hydraulic designs and erosion protection provided to meet NRC
regulations. NUREG-1623 (NRC, 2002) discusses acceptable methods for designing erosion
protection to provide reasonable assurance of effective long-term control and, thus, conform to
NRC requirements. NUREG-1623 (NRC, 2002) also provides discussions and technical bases for
use of specific criteria to meet the 1,000-year longevity requirement, without the use of active
maintenance, Speciflc design methods are provided and form the primary basis for staff review of
erosion protection designs. "
A geologic map with accompanying cross section(s) is (are) needed to deflne the earth materials that will
be penetrated by the drainage ditch and that would line the sides and bottom of the ditch along its entire
reach. This information is needed to support the design of the channel to ensure the adequacy of the
design for providing long-term erosion protection. Additional information needs to be provided to
demonstrate the adequacy of the sedimentation basin and Cell 1 discharge channel system with respect to
long-term scour and erosion protection, and to justify that the design is based on or considers potentially
applicable design guidelines. This necessary information needs to be provided.
The suitability of the proposed allowable peak channel velocity of 8-10 fps, based on the assumption of
bedrock material, has not been demonstrated. Published guidance documents (e.g., see Nelson, et al
1986) recommend a maximum allowable velocity for bedrock material of 6-8 fps. The allowable peak
velocities would be lower for substrates consisting of non- bedrock materials. This inconsistency needs to
be resolved.
Geologic conditions that could justify factoring in various adjustments into the determination of an
appropriate Manning 'n' value or range of Manning 'n' values s for (various segments of) the channel
are likely to vary along the reach of the proposed Cell 1 drainage channel Incorporating correction
factors to the 0.025 suggested Manning 'n' coefficient that account for roughness of the bedrock material
should be considered. The selected (base) value of0.025 assumes a smooth bedrock-lined channel along
the entire channel length. It is likely that the channel would exhibit some irregularity and variability
along its length. For example, the channel could have variable degrees of roughness due to initial
blasting vs. ripping of rock during channel constmction; differences in subgrade geologic conditions (e.g.
lithology); and possible variable amounts of accumulation of debris, vegetation, and roots within the
channel over the long term as a result of natural processes; differential erosion effects; and other factors
or processes. Appropriate adjustments (e.g., see Acrement and Schneider 1989) should be included to
account for such factors in the determination of appropriate Manning coefficient(s) for the discharge
channel along the channel's reach.
The slope stability analysis provided in the Revision 4 Reclamation Plan is applicable to a flnal cover
system that the DRC understands may yet be modifled. If at some future date, the cover system is
modifled, the flnal slope stability analyses would need to be re-evaluated to ensure it is directly
applicable.
As a part ofa proposed engineering design for tailings Cell 4B, DUSA provided a Technical
Memorandum (Tetra Tech 2010) that contains an updated seismic hazard evaluation study that includes:
• Summary of seismic studies done through 2006 to develop a design peak ground acceleration
(PGA) for the design of disposal cells and for use during the operational period of those cells
• Review of updated data (through January 2010) on seismic activity within 200 miles of the White
Mesa Mill Site
Interrogatory 03/01:10CFR40, Appendix A, Criterion 4: Location and Design Requirements Page 21 of 44
• Derivation of an updated predicted peak horizontal ground acceleration (peak HGA) value,
based on a 10,000-year return period, for use in the flnal disposal closure design effort for
proposed Cell 4B.
The study addressed updated published information, including the most recent USGS National Seismic
Hazard Maps, and also considered other studies, including 2008 deaggregation data. Next Generation
Attenuation Project information from 2007, and consideration of an updated attenuation relationship
published in 2007. Updated evaluation should, therefore, be described, applied to, and referenced in the
flnal slope stability analyses in Reclamation Plan, Rev. 4.0.
REFERENCES:
Abt, S.R., Thomton, C.I, Gallegos, H., and Ullmann, C. 2008. "Round-Shaped Riprap Stabilization in
Overtopping Flow," Joumal of Hydraulic Engineering, Vol 134, No. 8, August 2008, pp. 1035-
1041.
Abt, S.R., Johnson, T.L., Thornton, C.I, and Trabant, S.C 1998. "Riprap Sizing at Toe of Embankment
Slopes, " Journal of Hydraulic Engineering, Vol. 124, No. 7, July 1998, pp. 672-677.
Acrement, G.J, and Schneider, V.R. 1989. Guide for Selecting Manning's Roughness Coefficients for
Natural Channels and Flood Plains. United States Geological Survey Water-supply Paper 2339.
URL: http://www.fhwa.dot.gov/bridge/wsp2339.pdf.
Daniel, D.E. (Editor) 1993. Geotechnical Practice for Waste Disposal Chapman (& Hall Publishers, 2-6
Boundary Row, London, UK, 677pp.
Denison Mines (USA) Corporation. 2009a. Reclamation Plan, Revision 4.0, White Mesa Mill, Blanding,
Utah, Exhibit C: November 2009
Denison Mines (USA) Corp. 2009b. " Re: Cell 4B Lining System Design Report, Response to DRC
Request for Additional Information - Round 3 Interrogatory, Cell 4B Design ", Exhibit C:
Probable Maximum Precipitation (PMP) Event Computation, White Mesa Mill - Cell 4B,
Blanding, Utah". September 10, 2009. Letter to Dane Finerfrock, dated September 11, 2009.
DOE (U.S. Department of Energy). 1989. Technical Approach Document, Revision II UMTRA-DOE/AL
050425.0002.
DOE 1995. Uranium Mill Tailings Remediation Action Project, Slick Rock, Colorado. Subcontract
Documents: Bid Schedule, Special Conditions, Speciflcations, Subcontract Drawings. February
1995.
DOE. 2009a. 2008 UMTRCA Title I Annual Report: Slick Rock, Colorado. January 2009.
DOE. 2009b. 2008 UMTRCA Title I Annual Report: Rifle, Colorado. January 2009.
DOE. 2009c. 2008 UMTRCA Title I Annual Report: Grand Junction, Colorado. January 2009.
DOE. 2009d. 2008 Annual Inspection Report for the Weldon Spring, Missouri Site. January 2009.
DOE. 2000. WSSRAP Disposal Facility Technical Specifications, Section 2300: Waste Removal,
Handling, and Placement WP-437, Disposal Cell Constmction. May 15, 2000.
DOT (U.S. Department of Transportation).Federal Highway Administration. 2006. Hydraulic Design of
Energy Dissipators for Culverts and Channels. Hydraulic Engineering Circular No. 14, Third
Edition, PublicationNo. FHWA-NHl-06-086, 286pp. URL:
http://www.fhwa.dot.gov/engineering/hydraulics/pubs/06086/.
lnten-ogatory03/01:10CFR40, Appendix A, Criterion 4: Location and Design Requirements Page 22 of 44
EPA (U.S. Environmental Protection Agency). 1989a. Final Covers on Hazardous Waste Landfllls and
Surface Impoundments, Technical Guidance Document, EPA/53 O-SW-89-047, Office of Solid
Waste and Emergency Response, Washington, D. C. URL:
http://webcache.googleusercontent.com/search?q=cache:VEVCaJfyPDQJ:nepis.epa.gov/Exe/Zy
PURL.cgi%3FDockey%3D100019HCtxt+site:epa.gov+EPA+Final+Covers+Guidance(Sicd=4(&
hl-en&ct=clnk&gl-us.
EPA. 1991. Seminar Publication, Design and Constmction of RCRA/CERCLA Final Covers. EPA/625/4-
91/025. May 1991, 208 pp
EPA. 2004. (Draft) Technical Guidance for RCRA/CERCLA Final Covers. USEPA 540-R-04-007,
OSWER 9283.1-26. April 2004, 421 pp. URL:
nepis. epa.gov/Exe/ZyPURL. cgi?Dockey=Pl 0074PP. txt
Gilbert, P.A., and Murphy, W.M. 1987. Prediction/Mitigation of Subsidence Damage to Hazardous Waste
Landfill Covers. EPA/600/2-87/025, March 1987, 81 pp. NTIS PB-175386.
Itasca 2009. FLAC3D® - Advanced Three Dimensional Continuum Modeling for Geotechnical Analysis
of Rock, Soil, and Structural Support. Itasca. URL: http://www.itascacg.com/fiac3d/index.php.
Koerner, R.M. and Daniel, D.E., 1994, "Technical Equivalency Assessment of GCLs to CCLs ",
Geosynthetic Liner Systems: Innovations, Concems and Designs, Koerner, R.M. and Wilson-
Fahmy, R.F. Editors, IFAI, 1994, proceedings of a conference held in Philadelphia,
Pennsylvania, USA, pp. 265-285.
Nelson, JD., Abt, S.R., Volpe, R.L, van Zyf D., Hinkle, N.E., and Staub, W.P. 1986. Methodologies for
Evaluating Long-Term Stabilization Designs of Uranium Mill Tailings Impoundments. Prepared
for Nuclear Regulatory Commission, Washington, DC. NUREG/CR-4620, ORNL/TM-10067.
June 1986, 151 pp.
NRC (U.S. Nuclear Regulatory Commission). 1992. Preparation of Environmental Reports for Uranium
Mills, Regulatory Guide 3.8, October, 1992.
NRC 2002. U.S. Nuclear Regulatory Commission, "Design of Erosion Protection for Long-Term
Stability", NUREG-1623, September2002.
NRC. 2003. Standard Review Plan for the Review of a Reclamation Plan for Mill Tailings Sites under
Title II of the Uranium Mill Tailings Radiation Control Act of1978. Washington DC, June 2003.
Rawls, W.J, and Brakensiek, D.L. 1982. "Estimating Soil Water Retention from Soil Properties, "Joumal
ofthe Irrigation and Drainage Division, American Society of Civil Engineers, Vol. 108, No. IR2,
pp. 166-171.
Robinson, KM. Rice, C.E., and Kadavy, K.C. 1998. Design of Rock Chutes. Transactions of ASAE, Vol.
41, No. 3, pp. 621-626. URL:
http://www. ksda.gov/includes/document_center/stmctures/Stmctures/HL 178.pdf
Tetra Tech 2010. Technical Memorandum - White Mesa Uranium Facility, Seismic Study Update for a
Proposal Cell, Blanding, Utah, Febmary 3, 2010, Attachment E to Denison Mines (USA) Corp.,
White Mesa Uranium Mill - Second Round of Interrogatories from Review of License Amendment
Request and Environmental Report for Cell 4B, Febmary 8, 2010.
Interrogatory 03/01:10CFR40, Appendix A, Criterion 4: Location and Design Requirements Page 23 of 44
INTERROGATORY WHITE MESA RECPLAN 04/01: 10CFR40, APPENDIX A, CRITERION
6(1): COVER AND CLOSURE AT END OF MILLING OPERATIONS
REGULA TORY BASIS:
UAC R313-24-4 invokes the folio-wins requirement fr'om 10CFR40. Appendix A, Criterion 6(1): "In
disposing of waste byproduct material, licensees shall place an earthen cover (or approved alternative)
over tailings or wastes at the end of milling operations and shall close the waste disposal area in
accordance with a design which provides reasonable assurance of control of radiological hazards to (i)
be effective for 1,000 years, to the extent reasonably achievable, and, in any case, for at least 200 years,
and (ii) limit releases of radon-222from uranium byproduct materials, and radon-220from thorium
byproduct materials, to the atmosphere so as not to exceed an average release rate of 20 picocuries per
square meter per second (pCi/m^s) to the extent practicable throughout the effective design life
determined pursuant to (l)(i) of this criterion. In computing required tailings cover thicknesses, moisture
in soils in excess of amounts found normally in similar soils in similar circumstances may not be
considered. Direct gamma exposure from the tailings or wastes should be reduced to background levels.
The effects of any thin synthetic layer may not be taken into account in determining the calculated radon
exhalation level If non-soil materials are proposed as cover materials, it must be demonstrated that these
materials will not crack or degrade by differential settlement, weathering, or other mechanism, over long-
term intervals. "
INTERROG A TOR Y STA TEMENT:
1. Radon Flux (Refer to Sections 3.3.1 and 3.3.2 and Attachment F, including Table 1, to the
Reclamation Plan, Rev. 4.0) [Note: This interrogatory item was previously provided to DUSA in
January 2010 as part of the Round 2 Interrogatories submitted on the Cell 4B Environmental
Report]:
b. Please provide information describing the specific soil moisture data that are proposed to
be used in the future radon emissions calculations, where the proposed clay borrow
material soil samples tested are located in relation to the White Mesa Mill Site, and
information on the sampling depths of the clay borrow soil samples.
c. Please provide information regarding the laboratory test method that was used for
determining the long-term moisture content of the clay soil samples tested.
d. Please provide information regarding adjustments, if any, that were made to account
(adjust) for differences in site conditions at the borrow site(s) compared to the Mill Site,
with information to support such adjustments.
e. Please provide information justifying that the long-term moisture content selected to
represent the radon barrier layer in the radon emission calculations is conservative (e.g.,
relative to guidance provided in NRC Regulatory Guide 3.64 [NRC 1989] and Technical
Approach Document, Rev 2, 1989, UMTRA-DOE/AL 050425.0002, DOE 1989, Section 7).
Response:
This interrogatory references the cover design presented in the Denison's 2009
Reclamation Plan. Denison has proposed an evapotranspiration (ET) cover for
reclamation of the tailings cells. The updated design is presented in the 2011
Reclamation Plan. The response to the comments in this interrogatory is applicable to
Interrogatory 04/01:10CFR40, Appendix A, Criterion 6(1): Cover and Closure at End of Milling Operations Page 24 of 44
the updated cover design. Radon emanation modeling results are provided in Appendix
C of the Updated Tailings Cover Design Report.
BASIS FOR INTERROG A TOR Y:
Attachment F of the Reclamation Plan, Table 1 ("Selected Model Input Data "), lists water content
percentages for the radon barrier layer from locations listed as Clay (Site #1), Clay (Site #2), and Clay
(UT-1). However, no information has been provided as to where these three samples were collected at the
borrow area(s), or the depths from which they were collected. Also, in Attachment F of the Reclamation
Plan, Table 1, the footnote given for the 14.1%) moisture content value listed states that this percentage
was selected based on an "average of two tests ". No laboratory analysis results/data or information on
types of soil test methodologies used was included. Likewise, no information was provided regarding any
adjustments that were made, if any, to the laboratory soil testing results to account for differences in soil
conditions between the borrow site(s) and the engineered condition(s) that will exist at Mill Site after
cover construction.
NRC Regulatory Guide 3.64 (NRC 1989) specifies that information on the location of the clay borrow
site(s) proposed for supplying clay soils for the clay radon barrier layer in final disposal cell covers
needs to be provided with adjustments made, as appropriate, to account for any differences in conditions
between the borrow site(s) and the disposal site as necessary. Also, it is recommended that samples ofthe
clay soil materials be obtained from depths between 120 and 500 cm. In the information provided by
DUSA (e.g., Table 1 in Attachment F of the Reclamation Plan, Revision 4.0), the submittal suggests that
the long-term soil moisture content value selected for use in a previous radon barrier emission
calculation was estimated from an "average of two tests. " That approach does not appear to be
conservative with respect to guidance contained in Section 7.1.1 of DOE 1989, which states that "all
design parameters, except moisture content, are average values; (however) moisture content is
conservatively estimated. " DOE 1989, Section 7.1.3, describes ASTM laboratory soil test methods
considered acceptable for determining long-term moisture contents. As an acceptable altemative, a
conservative long-term moisture content for the radon barrier layer for radon emissions calculations can
be determined using a relationship such as the one described in NRC Regulatory Guide 3.64 developed
by Rawls and Brakensiek (1982).
REFERENCES:
DOE (US. Department of Energy). 1989. Technical Approach Document, Revision II. UMTRA-DOE/AL
050425.0002.
NRC (US. Nuclear Regulatory Commission). 1989. Regulatory Guide 3.64 (Task WM 503-4) -
Calculation of Radon Flux Attenuation by Earthen Uranium Mill Tailings Covers. June 1989.
NRC. 2008. Standard Format and Content of License Applications for Conventional Uranium Mills,
Draft Regulatory Guide DG-3024, May, 2008.
NRC. 2003. Standard Review Plan (NUREG-1620) for Staff Reviews of Reclamation Plans for Mill
Tailings Sites Under Title II of The Uranium Mill Tailings Radiation Control Act, NUREG-1620,
June, 2003.
Rawls, W.J, and Brakensiek, D.L. 1982. "Estimating Soil Water Retention from Soil Properties," Joumal
ofthe Irrigation and Drainage Division, American Society of Civil Engineers, Vol. 108, No. IR2,
pp. 166-171.
Interrogatory 04/01:10CFR40, Appendix A, Criterion 6(1): Cover and Closure at End of Milling Operations Page 25 of 44
INTERROGATORY WHITE MESA RECPLAN 05/01: 10 CFR PART 40, APPENDIX A; UAC
R317-3-1; AND UAC R317-3: CONSTRUCTION QUALITY CONTROL AND ASSURANCE
PRELIMINARY FINDING:
Refer to R313-25-7. Specific Technical Information. The application shall include certain technical
information. The following information is needed to determine whether or not the applicant can meet the
performance objectives and the applicable technical requirements of R313-25:
...(10) Descriptions of quality assurance programs, tailored to low-level waste disposal including audit and
managerial controls, for the determination of natural disposal site characteristics and for quality control
during the design, constmction, operation, and closure of the land disposal facility and the receipt, handling,
and emplacement of waste.
Refer to R317-3-1(1.7). 1.7. Constmction Supervision. The applicant must demonstrate that adequate and
competent inspection will be provided during constmction. It is the responsibility of the applicant to
provide frequent and comprehensive inspection of the project
Refer to R317-3-10(4)(E). E. Construction Quality Control and Assurance. A constmction quality control
and assurance plan showing frequency and type of testing for materials used in constmction shall be
submitted with the design for review and approval Results of such testing, gradation, compaction, field
permeability, etc., shall be submitted to the Executive Secretary.
INTERROG A TOR Y STA TEMENT:
Please revise and expand the Quality Plan for Constmction Activities, White Mesa Project, Blanding,
Utah (Attachment B to the Reclamation Plan, Revision 4.0) and submit it as a Constmction Quality
Assurance/Quality Control Plan (CQA/QC Plan) for site reclamation. Provide an expanded CQAQC
Plan that at a minimum, provides the following:
1. Include an organization chart that has sufficient detail to show the lines of communication and
authority (reporting relationships and directions) between the different CQA/QC personnel and
entities.
Response No. 1:
An organizational chart is included in the CQA/QC Plan (Attachment B of the 2011
Reclamation Pian).
Include sufficient detail to indicate who is responsible (between the Site Manager, Quality
Control Officer, Quality Assurance officer, the DRC Project Manager, Quality Control
Technicians, and any others) for, and when acceptance of the constmction work identified will
occur.
Response No. 2:
This information is included in the CQA/QC Plan (Attachment B ofthe 2011 Reclamation
Plan).
inten-ogatory 05/01:10 CFR PART 40, Appendix A; UAC R317-3-1; and UAC R317-3: Constmction Quality Controi and Assurance Page 26 of 44
3. Clarify responsibilities and criteria for acceptance of work and procedures, required actions, and
timelines to remediate material specification or constmction errors when identifying and
responding to non-conformances, so that CQA/QC Plan clearly identifies responsibility
assignments or procedures for when there is non-conformance, and how these will be addressed
and corrected, and ensures the timely implementation and documentation ofthe completed
corrective measure(s).
Response No. 3:
This information is included in the CQA/QC Plan (Attachment B of the 2011 Reclamation
Plan).
4. Describe minimum required experience and qualifications for all personnel indentified in the
Organizational Stmcture section of the CQA/QC Plan.
Response No. 4:
This information is included in the CQA/QC Plan (Attachment B ofthe 2011 Reclamation
Plan).
5. Include information on the Quality Assurance Testing Laboratory, including minimum experience
and qualifications, and information indicating that the required test procedures and testing
frequencies prescribed in the final CQA/QC Plan (for samples obtained from the site during
reclamation activities) will be implemented by the testing laboratory. Please demonstrate that
this soils testing laboratory will be currently certified and accredited by the AASHTO Material
Reference Laboratory (AMRL) for all soil / engineering related tests conducted on earth
materials at the site.
Response No. 5:
This information is included in the CQA/QC Pian (Attachment B ofthe 2011 Reclamation
Plan).
List and describe all CQA/QC activities related to earthwork operations that will occur during
reclamation activities, including:
a. A listing of earthwork activities.
b. Procedures for observing and performing conformance testing ofproposed materials of
constmction, and for inspection and protection of soil stockpiles.
c. Information regarding the review and evaluation of testing performed by Contractor(s) and
review and approval of Contractor's proposed constmction methods and proposed
equipment.
d. A statement regarding procedures and (estimated maximum) timeframes required for de-
watering and stabilizing the tailings, including veriflcation settlement monitoring, and
obtaining approval from the DRC for the flnal waste flll grades and elevations before
placement of cover materials.
Inten-ogatory 05/01:10 CFR PART 40, Appendix A; UAC R317-3-1; and UAC R317-3: Constmction Quality Control and Assurance Page 27 of 44
e. A description of the constmction, implementation, and sample collection and testing
procedures for an initial test pad or pads or any additional test pad constmcted, if needed
as part of the reclamation activities. Discuss the size and slope (inclination) of each such
test pad; equipment to be used and number of equipment passes to be used; and how the
test pad(s) will be used to demonstrate and verify that fhe specifled minimum requirements
for the final cover system and other disposal system components, as appropriate, can
reliably be achieved during the construction work. Include information on the criteria to be
used for determining when a test pad is needed. Provide information on fhe types and
locations of tests to be conducted on the test pad. Provide test methods for testing density
(e.g., ASTM D-698 and/or ASTM D-l557), Atterberg Limits, particle size analysis,
moisture/density (nuclear method and sand cone) and moisture content, relatively
undisturbed saturated hydraulic conductivity, and in-situ large-scale saturated hydraulic
compacted clay layer in the test pad (e.g.. Sealed Double-Ring Inflltrometer method [ASTM
5093-02 (ASTM 2008)], or other DRC-approved large-scale in-situ sampling/testing
method), in accordance with applicable published guidance documents (e.g., Daniel and
Koerner 1993; Daniel and Koerner 2007; ASTM2008). Include a description of
temperature or other weather conditions and constraints that would be associated with test
pad constmction and procedures for reworking any areas where a failing test result (e.g.,
permeability in excess of the specifled minimum value) is obtained. Specify all ASTM
methods as applicable and testing frequencies (recommend use of a tabular format).
f. A description of measurements, inspections, observations to be made during constmction of
each of the cover system layers, including monitoring of moisture conditioning, mixing
and/or blending/processing for uniformity of material and content, fleld density tests, and
other parameters as appropriate. Specify (in the revised version of the Quality Plan in
Attachment B) all ASTM methods as applicable and testing frequencies (recommend use
of a tabular format). Indicate all applicable and relevant guidance and standards that will
be addressed by the testing and inspection program, including NUREG/CR-3356 (NRC
1983); NRC Regulatory Guide 3.11, Rev. 3 (NRC 2008); ASTM Standards, and other
guidance considered applicable and relevant (e.g., Daniel and Koerner 1993; Daniel and
Koerner 2007). Include descriptions ofprocedures for observing, testing, and documenting
placement and compaction activities of each layer of the flnal cover system, including lift
thickness placement, compaction equipment usage, and number of passes made with
equipment. Include information on observations and sampling procedures related to
construction and testing of:
• The "platform flll and grading layer;"
• The upper portion (sublayer) of the "platform flll and grading layer", including specifled
restrictions on, or prohibition of, debris waste placement within that sublayer, and the
thickness of that sublayer for which such restrictions or prohibition will apply);
• The radon barrier layer;
• The "compacted random flll layer" (frost barrier and water storage layer; and/or
• Any other layers proposed for inclusion in the selected flnal cover system.
g. A description of temperature (or other weather conditions/constraints) and minimum
moisture content (desiccation prevention) that would be associated with the radon barrier
layer constmction.
h. A description ofprocedures to be followed to rework materials in portions of layers for
which a failing test result occurs and procedures for notiflcation of the Site Manager and
the DRC Manager for any failed test or failed retest result or for directing and approving
Interrogatory 05/01:10 CFR PART 40, Appendix A; UAC R317-3-1; and UAC R317-3: Constmction Quality Control and Assurance Page 28 of 44
further reworking of the failing material. Please include a description of maximum
timeframes for such verification testing, required approvals and notiflcation and approval
time frames. Specify all ASTM methods as applicable and related testing frequencies.
i. A description ofprocedures for conducting and documenting post-constmction inspections
and for completing corrective actions and materials testing, as required, in conjunction
with constmction of the compacted layer prior to its flnal acceptance.. Such activities
should include inspecting for any cracks/desiccation in the compacted clay layer;
inspecting any areas that are damaged or improperly mixed or compacted; and inspecting:
• Clod sizes (prior to compaction)
• Presence of areas that have been excessively eroded by rainfall or as a result of
constmction activities
• Areas containing excessive organic material or other deleterious and/or unsuitable (e.g.,
uncompactable) materials
• Depressions
• Other irregularities in the cover layers
• Procedures for completing and recording any repairs performed.
j. A description of methods for repairing/backfilling and re-testing repairs made to address
any holes or unrepaired damage in the constmcted compacted clay layer (radon barrier
layer) from density tests, field permeability tests, or other tests.
k. Revised versions of Form No. F-2 3 (Compliance Report) and Form No. F-2 6 (Design
Change Order) to refiect approval of DRC Project Manager rather than that of the NRC
Project Manager.
I. A revised version of Form No. F-26 (Design Change Order) as needed to refiect the
current discrepancy between this form, which requires approval by the Design Engineer,
and the absence of a description of this position/person in Section 2 (Organizational
Structure) of the Quality Plan for Construction Activities (Attachment B).
m. A description of contents of a Final Certification/CQA Documentation Report that will be
prepared and submitted by the State of Utah registered Professional Engineer that
indicates that the project was constmcted in accordance with the constmction drawings,
specifications, and the CQA/QC Plan. The report should include, at a minimum, a summary
ofall CQAQC operations, construction equipment and processes, results, and observations
of conformance / verification testing, and any actions taken to resolve constmction
problems encountered, as-built drawing(s) and details, field notes, and photographs. The
report must be prepared under the supervision of and stamped with the seal of a Utah
registered Professional Engineer.
n. Include information indicating that the Quality Control Officer (CQO) for implementing
and managing the CQA/QC Plan during reclamation activities, as identified in Quality
Plan for Constmction Activities (Attachment B), will be an independent Utah registered
Professional Engineer, party who will conduct both direct field observations and document
reviews.
inten-ogatory 05/01:10 CFR PART 40, Appendix A; UAC R317-3-1; and UAC R317-3: Constmction Quality Controi and Assurance Page 29 of 44
Response No. 6:
The majority of the information requested in this interrogatory is included in the updated
Technical Specifications and CQA/QC Plan (Attachments A and B of the 2011
Reclamation Pian). information regarding the estimated time frames for dewatering and
settlement is provided in the Updated Tailings Cover Design Report.
BASIS FOR INTERROG A TORY:
Section 7 of Attachment A (Quality Control/Quality Assurance) of the Reclamation Plan, Revision 4, and
the Quality Plan for Constmction Activities (Attachment B to that Reclamation Plan) do not adequately
specify CQA/QC activities that will need to be completed and documented during the reclamation work at
the White Mesa Mill Site in order to permit a transparent, documented, and verifiable certification that
the project will have been constmcted in accordance with the constmction drawings, specifications, and
the CQA/QC Plan. Further, the information presented in Section 7 ofAttachment A of the Reclamation
Plan (Rev. 4.0) and in the Quality Plan for Constmction Activities (Attachment B to the Reclamation
Plan) does not address guidelines or incorporate several ASTM test methods (e.g., ASTM D-698, ASTM
D-1556, ASTMD-2487, ASTMD-2922, ASTMD-3017, ASTMD-2937, ASTMD-4318, ASTMD-4643,
ASTM D-5084) that have been either adopted or updated since the time the NRC last reviewed the White
Mesa Mill Reclamation Plan (early 2000s).
Sections 2.6.2 and 2.6.3 of NUREG-1620 (NRC 2003) indicate that a review be performed ofproposed
construction quality control programs for verifying that adequate provisions are in place for ensuring
that construction will be in accordance with the approved reclamation plan, and that such a review
include, in particular, details of the proposed testing and inspection program, including the type and
frequency of tests proposed, for comparison with NRC-specified guidance on testing and inspection ,
including NUREG/CR-3356 (NRC 1983).
Section 3.4 of NUREG-1620 (NRC 2003) identifies "constmction considerations, including
specifications, quality assurance programs, quality control programs ("...to ensure that adequate
measures are being taken to constmct the design features according to accepted engineering practices "),
and inspection programs, as a key area for review when conducting reviews of erosion protection designs
for reclamation plans.
With regard to compliance with requirements of 10 CFR Part 40, Appendix A, Criterion 5(A) that relates
to the design of liners for surface impoundments. Section 4.4.3 of NUREG-1620 indicates that "the
design ofa clay or synthetic liner and its component parts should be presented. At a minimum, design
details, drawings, and pertinent analyses should be provided and that expected constmction methods,
testing criteria, and quality assurance programs should be presented. Planned modes of operation,
inspection, and maintenance should be discussed in the application. " Although these guidelines apply to
clay liners, the same guidelines would be applicable to the compacted clay radon barrier layer in the
final cover system.
With respect to demonstrating compliance with radon attenuation criteria specified in 10 CFR Part 40,
Appendix A, Criterion 6(1) and Criterion 6(5), Section 5.3.1 of NUREG-1620 (NRC 2003) indicates that
"the materials testing programs [should] employ appropriate analytical methods and sufficient and
[ensure that] representative samples were tested to adequately determine material property values for
both cover soils and contaminated materials. In the absence of sufficient test data, [ensure that]
conservative estimates are chosen and justified... and [ensure that] the quality assurance program for
parameter data is adequate and the data are available for inspection. "
NRC's Regulatory Guide 3.11, Rev. 3 (NRC 2008) also provides some guidance relevant to typical testing
procedures and testing frequencies for some parameters during embankment constmction.
intenogatory 05/01:10 CFR PART 40, Appendix A; UAC R317-3-1; and UAC R317-3: Constmction Quality Controi and Assurance Page 30 of 44
Maximum estimated timeframes for completing dewatering of the tailings, a critical-path item for the
reclamation schedule, should be described in the Reclamation Plan so that a conservative estimate ofthe
costs for carrying out final reclamation, including conducting the CQA activities described in this
interrogatory, can be estimated for inclusion in the financial surety.
REFERENCES:
American Society for Testing and Materials (ASTM). 2008. Standard Test Method for Field Measurement
of Inflltration Rate Using a Double-Ring Inflltrometer with a Sealed Inner Ring, Test Designation
ASTM D5093 - 02(2008), American Society for Testing and Materials, West Conshohoken, PA,
2008.
Daniel, D. E., and Koerner, R.M. 1993. Technical Guidance Document: Quality Assurance and Quality
Control for Waste Containment Facilities. EPA/600/R-93/182. Office of Research and
Development, Washington, D.C. 305pp.
Daniel, D. E., and Koerner, R.M. 2007. Waste Containment Facilities - Guidance for Constmction
Quality Assurance and Constmction Quality Control of Liner and Cover Systems. 2"^ Edition.
ASCE Press, Reston, VA. 353 pp.
NRC (U.S. Nuclear Regulatory Commission) 1983. NUREG/CR-3356. Geotechnical Quality Control:
Low Level Radioactive Waste and Uranium Mill Tailings Disposal Facilities. Prepared for U.S
Nuclear Regulatory Commission, 108 pp. plus Appendices, July 1983.
NRC 2003. NUREG-1620: Standard Review Plan for the Review of a Reclamation Plan for Mill Tailings
Sites Under Title II of the Uranium Mill Tailings Radiation Control Act of1978. Washington DC,
June 2003.
NRC 2008. Regulatory Guide 3.11, Rev. 3. Design, Constmction, and Inspection of Embankment
Retention Systems at Uranium Recovery Facilities. November 2008.
Inten-ogatory 05/01:10 CFR PART 40, Appendix A; UAC R317-3-1; and UAC R317-3: Construction Quality Control and Assurance Page 31 of 44
INTERROGATORY WHITE MESA RECPLAN 06/01: 10CFR40, APPENDIX A, CRITERION 9:
FINANCIAL SURETY ARRANGEMENTS
REGULA TOR Y BASIS:
UAC R313-24-4 invokes the following requirement from 10CFR40, Appendix A. Criterion 9:
"Financial surety arrangements must be established by each mill operator prior to the commencement of
operations to assure that sufficient funds will be available to carry out the decontamination and
decommissioning of the mill and site and for the reclamation of any tailings or waste disposal areas. The
amount of funds to be ensured by such surety arrangements must be based on Executive Secretary-
approved cost estimates in an Executive Secretary-approved plan for (1) decontamination and
decommissioning of mill buildings and the milling site to levels which allow unrestricted use of these
areas upon decommissioning, and (2) the reclamation of tailings and/or waste areas in accordance with
technical criteria delineated in Section I of this Appendix. The licensee shall submit this plan in
conjunction with an environmental report that addresses the expected environmental impacts ofthe
milling operation, decommissioning and tailings reclamation, and evaluates altematives for mitigating
these impacts. The surety must also cover the payment of the charge for long-term surveillance and
control required by Criterion 10. In establishing specific surety arrangements, the licensee's cost
estimates must take into account total costs that would be incurred if an independent contractor were
hired to perform the decommissioning and reclamation work. In order to avoid unnecessary duplication
and expense, the Executive Secretary may accept financial sureties that have been consolidated with
financial or surety arrangements established to meet requirements of other Federal or state agencies
and/or local goveming bodies for such decommissioning, decontamination, reclamation, and long-term
site surveillance and control, provided such arrangements are considered adequate to satisfy these
requirements and that the portion of the surety which covers the decommissioning and reclamation ofthe
mill, mill tailings site and associated areas, and the long-term funding charge is clearly identified and
committed for use in accomplishing these activities. The licensee's surety mechanism will be reviewed
annually by the Executive Secretary to assure, that sufficient funds would be available for completion of
the reclamation plan ifthe work had to be performed by an independent contractor. The amount of surety
liability should be adjusted to recognize any increases or decreases resulting from infiation, changes in
engineering plans, activities performed, and any other conditions affecting costs. Regardless of whether
reclamation is phased through the life of the operation or takes place at the end of operations, an
appropriate portion of surety liability must be retained until final compliance with the reclamation plan is
determined.
This will yield a surety that is at least sufficient at all times to cover the costs of decommissioning and
reclamation of the areas that are expected to be disturbed before the next license renewal The term ofthe
surety mechanism must be open ended, unless it can be demonstrated that another arrangement would
provide an equivalent level of assurance. This assurance would be provided with a surety instmment
which is written for a specified period of time (e.g., 5 years) yet which must be automatically renewed
unless the surety notifies the beneficiary (the Executive Secretary) and the principal (the licensee) some
reasonable time (e.g., 90 days) prior to the renewal date of their intention not to renew. In such a
situation the surety requirement still exists and the licensee would be required to submit an acceptable
replacement surety within a briefperiod of time to allow at least 60 days for the regulatory agency to
collect
Proof offorfeiture must not be necessary to collect the surety so that in the event that the licensee could
not provide an acceptable replacement surety within the required time, the surety shall be automatically
collected prior to its expiration. The conditions described above would have to be clearly stated on any
surety instmment which is not open-ended, and must be agreed to by all parties. Financial surety
arrangements generally acceptable to the Executive Secretary are:
inten-ogatory 06/01; 10CFR40, Appendix A, Criterion 9: Financial Surety An-angements Page 32 of 44
(a) Surety bonds;
(b) Cash deposits;
(c) Certificates of deposits;
(d) Deposits of govemment securities;
(e) Irrevocable letters or lines of credit; and
(f) Combinations ofthe above or such other types of arrangements as may be approved by the Executive
Secretary. However, self insurance, or any arrangement which essentially constitutes self insurance (e.g.,
a contract with a State or Federal agency), will not satisfy the surety requirement since this provides no
additional assurance other than that which already exists through license requirements. "
INTERROG A TOR Y STA TEMENT:
1. Preliminary Decommissioning Plan
Please provide a preliminary Decommissioning Plan as an attachment to the Reclamation Plan (refer to
NUREG-1620, Rev. 1, Section 5.2) that describes expected decommissioning activities in sufficient detail
to support cost estimates for surety purposes. Please include the following elements and address them in
appropriate detail, as follows:
a. Plans and procedures for disconnecting, isolating, draining, removing and disposing of all
utilities including, but not limited to lines and appurtenances for telephone, electrical power,
natural and tanked gas, water supply, sewer (or septic tank drainfields), and fuels. Include
stmctures, tanks, piping and equipment used in conjunction with the uranium milling operations,
including the plan for managing all hazardous and radioactive materials.
b. Consider approaches for identifying radiological hazards before initiating dismantlement of
stmctures and equipment and for detection and cleanup of removable contamination from such
stmctures and equipment in order to minimize occupational radiation exposure.
c. Describe appropriate survey methods for determining the extent of equipment contamination
before initiating decontamination work. Focus, in particular, on those parts of the mill process
system that are likely to have accumulated contamination over long time periods (e.g., pipes,
ventilation, equipment, effiuent control systems, and facilities and equipment used in or near the
yellowcake dryer area). Describe any plans for the decontamination of equipment for release for
unrestricted use.
d. Measures for cleanup of windblown tailings and other soils contaminated from mill operations
and for sampling and surveys to document that soils have been cleaned to acceptable levels.
Address the means for disposing of any ore remaining on site following the cessation of mill
operations. Provide procedures to identify, excavate, transfer, and deposit within designated
tailings cells all soils on and adjacent to the processing site that exceed the standards in 10 CFR
Part 40, Appendix A, Criterion 6(6), due to site activities. Describe how the plan will be
substantiated by the radiological characterization data and site operating history. (Refer also to
Item 1 of Section 5.2.2 of NUREG-1620, Rev. 1 for additional guidance.)
e. Proposed soil background values (different geological areas may need separate background
values) for Ra-226, and for U-nat, Th-230, and/or Th-232, as appropriate. Said background
Interrogatory 06/01:10CFR40, Appendix A, Criterion 9: Financial Surety Anrangements Page 33 of 44
values must be justified with supporting soil sampling/ analytical data. (Refer also to Item 2 of
Section 5.2.2 of NUREG-1620, Rev. 1 for additional guidance.)
f. If elevated levels of uranium or thorium are expected to remain in the soil after the Ra-226
criteria have been met, a commitment to use the "radium benchmark dose approach described in
Appendix H of NUREG-1620, Rev. 1 in developing decommissioning criteria forthe
radionuclides that remain at elevated levels. (Refer also to Item 3 of Section 5.2.2 of NUREG-
1620, Rev. 1 for additional guidance.)
g. Modify the plan to ensure that the instmmentation and procedures used for soil background
analyses and the radium-gamma correlation are the same or very similar to those proposed to
provide verification data to ensure consistency of measurement data. Please also demonstrate
how the proposed instmmentation has the appropriate sensitivity, and that proposed soil
sampling / analytical procedures are adequate to provide reliable soil activity data. (Refer also to
Items 4 and 5 of Section 5.2.2 of NUREG-1620, Rev. 1 for additional guidance.)
h. A detailed quality assurance and quality control plan for all aspects of decommissioning. Provide
and justify the basis for accepting or rejecting data and a procedure for sampling additional
grids when a verification Ra-226 sample fails to meet the standard. (Refer also to Item 6 of
Section 5.2.2 of NUREG-1620, Rev. 1 for additional guidance.)
i. Final verification (status survey) procedures that demonstrate compliance with the site soil and
stmcture cleanup standards. Specify survey instmments and provide procedures for their proper
calibration and testing. The proposed verification soil sampling density must consider and justify
(1) detection limits of sample analyses, (2) the extent of expected contamination (unaffected area
could have fewer measurements than affected areas), and (3) limits to the gamma survey for the
potentially contaminated area to be sampled. Justify the gamma guideline value to be used for
verification. Commit to provide the verification soil radium-gamma correlation and the number
of verification grids that had additional removal because of excessive Ra-226 values, to confirm
that the gamma guideline value was adequate. Commit to providing adequate data collection
beyond the excavation boundary (buffer zone). For stmctures expected to remain onsite, provide
plans and procedures that will demonstrate compliance with the limits for the surface activity
dose in Appendix H of NUREG-1620, Rev. 1. (Refer also to Item 7 of Section 5.2.2 of NUREG-
1620, Rev. 1 for additional guidance.)
j. The location where will be maintained records important to decommissioning procedures,
documenting the protection of health and safety, and demonstrating that decommissioning was
completed as soon as practicable, as required by 10 CFR 40.42 and Appendix A, Criterion 6A.
(Refer also to Item 8 of Section 5.2.2 of NUREG-1620, Rev. 1 for additional guidance.)
k. A description of methods to be used to control non-radiological hazards associated with the
wastes as required by 10 CFR Part 40, Appendix A, Criterion 6(7). (Refer also to Item 9 of
Section 5.2.2 of NUREG-1620, Rev. 1 for additional guidance on cost elements appropriate for
establishing surety amounts for conventional uranium mills.)
I. Procedures, equipment, and maximum timeframes needed for tailings de-watering and
stabilization, including settlement monitoring stands, elevation surveys, generation of reports,
and related performance criteria.
interrogatory 06/01:10CFR40, Appendix A, Criterion 9: Financial Surety An-angements Page 34 of 44
m. Qualifications, skills and abilities of all personnel involved in the reclamation and
decommissioning process, including but not limited to: site sampling / inspections, consulting,
and closure report preparation.
n. Minimum number, types, and locations of samples to be collected and analyzed to verify closure
constmction, decommissioning, and decontamination of the site.
o. Minimum number, types and locations of Radon-222 measurements to be made after embankment
closure to confirm and verify compliance with NESHAPS requirements (see Interrogatory
WhiteMesa RecPlan 07/01, below).
Response No. 1:
The majority of the information requested in this interrogatory is included in the
Preliminary Mili Decommissioning Plan submitted to the Executive Secretary as
Appendix G of the 2011 Reclamation Plan. Procedures for cleanup of windblown
contamination and other contaminated soils are outlined in the updated Technical
Specifications (Attachment A of the 2011 Reclamation Plan).
Additional detail requested in this interrogatory and not currently included in the 2011
Reclamation Plan documents for the soil cleanup plan wili be provided as part of
preparation of the final Miil Decommissioning Pian to be submitted to the Utah DRC for
approval within twelve months prior to commencement of decommissioning activities. A
detailed CQA/QC Plan is provided as Attachment B of the 2011 Reclamation Plan.
Information regarding dewatering, final cover verification, settlement analyses, and the
settlement monitoring plan is provided in the Updated Tailings Cover Design Report.
Foliowing final design of the reclamation cover, Denison wiii submit an Emissions
Measurement Plan to the DRC for review. The Emissions Measurement Plan will
provide a map showing the extent of the tailings disposal cells and reclamation cover, as
well as the measurement locations for the radon emissions testing. This Emissions
Measurement Plan will be developed in accordance with procedures outiined in 40 CFR
Part 61, Appendix B, Method 115.
2. Cost Estimates for Reclamation and Decommissioning (Refer to Section 3, Attachment A, and
Attachment C of the Reclamation Plan):
It is pmdent to provide a reclamation and decommissioning cost estimate with the revised Reclamation
Plan, that itemizes each cost component in sufficient detail and that defines the basis for each cost
component. The licensee should demonstrate that the total cost is reasonably conservative for the area of
the site and the expected reclamation and decommissioning activities. (Refer also to Item 10 of Section
5.2.2 and Appendix C of NUREG-1620, Rev. 1 for additional guidance.)
a. Provide estimated costs for completing final closure of the Mill Facility, including the costs for
constmcting those revised final closure cover and drainage systems and appurtenances for
determining/verifying the financial surety requirements for the White Mesa Mill with all tailings
management cells, including Cells 4A and 4B, and any new stmctures, features, or other
appurtenances associated therewith.
inten-ogatory 06/01:10CFR40, Appendix A, Criterion 9: Financial Surety Arrangements Page 35 of 44
b. Provide updated information and details pertaining to anticipated required reclamation activities
for any tailings or waste disposal areas or other contaminated areas, including contaminated
groundwater plumes known to have originated from the mill and its facilities and operations, viz.,
the chloroform plume. Provide cost estimates for each required reclamation activity.
Probabilistic cost estimates can be used to represent the costs of completing required remedial
activities where uncertainty exists, such as remediation of groundwater plumes. Software
packages that would support the development of probabilistic cost estimates include Crystal
Ball®, @Risk®, and GoldSim®, all of which are commercially available and allow cost elements
to be defined as probability distributions and develop cost distributions using Monte Carlo
simulations.
c. Provide updated cost estimates for carrying out the preliminary Decommissioning Plan.
d. Please provide a commitment to submit the final decommissioning plan for the Division's review
12 months ahead of scheduled closure as required by UAC R313-22-36(4).
Response No. 2:
An updated Reclamation Cost Estimate is provided as Attachment C of the 2011
Reclamation Plan.
A Preliminary Mili Decommissioning Plan was submitted to the Executive Secretary as
Appendix G of the 2011 Reclamation Pian. As stated in the plan, a final
decommissioning plan will be submitted to the Utah DRC for approval within twelve
months prior to commencement of decommissioning activities
BASIS FOR INTERROGATORY:
NRC Regulatory Guide 3.8 (NRC 1982), Chapter 9, indicates that detailed discussions should be
provided for the following:
1. Plans for reclaiming and restoring lands disturbed by mining and milling activities. These plans
should provide sufficient details for the staff to assess the suitability of these plans when
compared to other alternatives (e.g., horizontal-vertical slope, type of cover, sources and
thicknesses of cover materials, revegetation species, schedule of events from shutdown through
final reclamation).
2. A technical and financial feasibility assessment on methods and costs of mill decommissioning
and site reclamation, including tailings area.
3. Financial arrangements to be made (such as bonding arrangements) to ensure that adequate
funds will be available for mill decommissioning, site reclamation, and restoration when
operations are concluded."
NRC Draft Guide (DG)-3024 (NRC 2008), Section 8.3, also indicates that Criterion 9 of Appendix A to
10 CFR Part 40 specifies that each mill operator must establish financial surety arrangements before the
commencement of operations to ensure that sufficient funds will be available to carry out the
decontamination and decommissioning of the mill and site and for the reclamation ofany tailings or
waste disposal areas. In the application, a licensee should provide sufficient information to verify that the
amount of coverage provided by a flnancial surety arrangement will permit the completion ofall
decontamination, decommissioning, and reclamation of sites, stmctures, and equipment used in the
recovery and production of uranium and the concomitant generation of byproduct material This
document also specifles that a licensee should calculate the cost estimate on the basis of completion ofall
activities by a third party. The surety must also cover the payment of the charge for long-term
Interrogatory 06/01:10CFR40, Appendix A, Criterion 9: Financial Surety Arrangements Page 36 of 44
surveillance and control of the site as required by Criterion 10 of Appendix A to 10 CFR Part 40 (See
Appendix C to NUREG-1620for additional information on the scope and content of the cost information
to be submitted for flnancial assurance purposes.)
NUREG-1620 (NRC 2003), Section 4.4.3(10), specifles that a licensee must maintain a flnancial surety
for the cleanup of contaminated ground water, with the surety sufficient to cover the anticipated cost and
time frame for achieving compliance, before the land is transferred to the long-term custodian. This
document also indicates that the flnancial surety must be sufficient to cover the cost of corrective action
measures that will have to be implemented if required to restore goundwater quality to the established
site-speciflc standards before the site is transferred to the govemment for long-term custody. Guidance
on establishing financial surety is presented in NRC 1988 and NRC 1997. Appendix C to this standard
review plan provides an outline of the cost elements appropriate for establishing surety amounts for
conventional uranium mills. The document indicates that flnancial surety review should be considered
acceptable ifthe applicant's assessment and independent assessment of the surety amounts are
reasonably consistent.
A cost estimate for completing corrective action of existing identifled groundwater contamination known
to have originated from the mill and its facilities and operations needs to be provided and be included in
the flnancial surety. Probabilistic cost estimates can be used when uncertainty exists in the parameters
that enter into the cost estimate, including quantities, unit costs, and lump sum estimates. Based on
information about these cost elements, the cost elements can be represented as probability distributions.
The probability distribution for the cost elements can then be evaluated randomly hundreds or thousands
of times in a Monte Carlo simulation to develop a distribution of estimated costs. Given the required
level of confldence that actual costs will not exceed flnancial assurances provided, the cost estimate
distribution can be used to determine the required level of financial assurance. The costs can be
estimated using probabilistic techniques and to an extent dictated by the amount of information that is
available. As more deflning data become available, uncertainty in the cost estimate can be reflected by
revising the probability distributions that represent the cost elements, thereby reducing the uncertainty of
the cost estimate.
Finally, NUREG-1620 (NRC 2003), Section 5.2.3, specifies that, as required by 10 CFR Part 40
Appendix A Criteria 9 and 10, a licensee must maintain a financial surety, within the specific license, for
the surface reclamation and decommissioning, with the surety sufficient to recover the anticipated cost
and time frame for achieving compliance, and include the long-term surveillance as outlined in guidance
for establishing financial surety arrangements, as presented in NRC 1988 and NRC 1997. Appendix C to
NUREG-1620provides an outline of the cost elements appropriate for establishing surety amounts for
conventional uranium mills.
REFERENCES:
Denison Mines (USA) Corporation. 2009. Reclamation Plan, Revision 4.0, White Mesa Mill, Blanding,
Utah, November 2009.
NRC (U.S. Nuclear Regulatory Commission). 1988. Technical Position on Financial Assurances for
Restoration, Decommissioning, and Long-Term Surveillance and Control of Uranium Recovery
Facilities. Washington DC.
NRC. 1982. Preparation of Environmental reports for Uranium Mills, Regulatory Guide 3.8, October
1992.
NRC. 1997. Annual Financial Surety Update Requirements for Uranium Recovery Licensees. Generic
Letter 97-03. Washington, DC: NRC. July 1997.
Inten-ogatory 06/01:10CFR40, Appendix A, Criterion 9: Financial Surety Arrangements Page 37 of 44
NRC. 2003. Standard Review Plan for the Review of a Reclamation Plan for Mill Tailings Sites Under
Title II of the Uranium Mill Tailings Radiation Control Act of1978. NUREG-1620. Washington
DC, June 2003.
NRC. 2008. Standard Format and Content of License Applications for Conventional Uranium Mills,
Draft Regulatory Guide DG-3024, May 2008.
U.S. Nuclear Regulatory Commission, "Environmental Review Guidance for Licensing Actions
Associated with NMSS Programs. " NUREG-1748, Washington, DC, 2001.
U.S. Nuclear Regulatory Commission, "Standard Review Plan for the Review of a Reclamation Plan for
Mill Tailings Sites Under Title II of the Uranium Mill Tailings Radiation Control Act of1978. "
NUREG-1620, Revision 1, Washington DC, June 2003.
U.S. Nuclear Regulatory Commission, "Regulatory Guide 3.8; Preparation of Environmental Reports for
Uranium Mills", Washington DC, October 1982.
Interrogatory 06/01:10CFR40, Appendix A, Criterion 9: Financial Surety An-angements Page 38 of 44
INTERROGATORY WHITE MESA RECPLAN 07/01:11E.(2); 10CFR40, APPENDIX A,
CRITERION 6(2); 6(3); 6(4): VERIFY EFFECTIVENESS OF FINAL RADON BARRIER, AND
PHASED EMPLACEMENT OF FINAL RADON BARRIER, AND REPORT RADON BARRIER
EFFECTIVENESS
REGULA TOR Y BASIS:
UAC R313-24-4 invokes the following requirement from 10CFR40, Appendix A. Criterion 6(2):
"As soon as reasonably achievable after emplacement of the final cover to limit releases of radon-222
from uranium byproduct material and prior to placement of erosion protection barriers or other features
necessary for long-term control of the tailings, the licensee shall verify through appropriate testing and
analysis that the design and constmction of the final radon barrier is effective in limiting releases of
radon-222 to a level not exceeding 20 pCi/m^s averaged over the entire pile or impoundment using the
procedures described in 40 CFR part 61, appendix B, Method 115, or another method of verification
approved by the Executive Secretary as being at least as effective in demonstrating the effectiveness of the
final radon barrier."
UAC R313-24-4 invokes the followins requirement from 10CFR40, Appendix A, Criterion 6(3):
"When phased emplacement of the fmal radon barrier is included in the applicable reclamation plan, the
verification of radon-222 release rates required in paragraph (2) of this criterion must be conducted for
each portion ofthe pile or impoundment as the final radon barrier for that portion is emplaced. "
UAC R313-24-4 invokes the followins requirement fr-om 10CFR40, Appendix A, Criterion 6(4):
"Within ninety days of the completion of all testing and analysis relevant to the required verification in
paragraphs (2) and (3) of 10CFR40, Appendix A. Criterion 6, the uranium mill licensee shall report to the
Executive Secretary the results detailing the actions taken to verify that levels of release of radon-222 do
not exceed 20 pCi/m^s when averaged over the entire pile or impoundment. The licensee shall maintain
records until termination of the license documenting the source of input parameters including the results
ofall measurements on which they are based, the calculations and/or analytical methods used to derive
values for input parameters, and the procedure used to determine compliance. These records shall be
kept in a form suitable for transfer to the custodial agency at the time of transfer of the site to DOE or a
State for long-term care if requested. "
INTERROGATORY STATEMENT:
Effectiveness of Final Radon Barrier (Refer to Sections 3.3.2 of the Reclamation Plan and Attachment
B, Quality Plan for Construction):
1. Please provide the proposed methods, sets of criteria, type of testing, testing frequency, and form of
documentation that will be used to verify that the design and constmction of the flnal radon barrier is
effective in limiting releases of radon-222 to a level not exceeding 20 pCi/m^s, averaged over the
entire pile or impoundment. Indicate that this veriflcation will be completed using procedures
described in 40 CFR Part 61, Appendix B, Method 115, or another method of verification approved
by the Executive Secretary as being at least as effective in demonstrating the effectiveness of the final
radon barrier.
Response No. 1:
Discussion of final cover verification is provided in the Updated Tailings Cover Design
Report. Testing requirements and frequency of testing for the final cover verification are
Interrogatory 07/01:11E.(2); 10CFR40, Appendix A, Criterion 6(2); 6(3); 6(4): Verify Effectiveness of Final Radon Banier,
and Phased Emplacement of Final Radon Banier, and Report Radon Banier Effectiveness Page 39 of 44
provided in the updated Technical Specifications and CQA/QC Plan (Attachments A and
B of the 2011 Reclamation Plan). Following final design of the reclamation cover,
Denison will submit an Emissions Measurement Pian to the DRC for review. The
Emissions Measurement Pian will provide a map showing the extent of the tailings
disposal ceils and reclamation cover, as weil as the measurement locations for the radon
emissions testing. This Emissions Measurement Pian wiii be developed in general
accordance with procedures outlined in 40 CFR Part 61, Appendix B, Method 115.
2. Please provide a clear schedule indicating whether the radon barrier layer will be installed in phases
or as a continuous placement of the layer over the tailings management cells area(s), and provide a
schedule for completing radon emissions verification testing that is based on, and clearly tied to, that
radon barrier placement schedule.
Response No. 2:
See Response No. 1. The schedule for construction of the final cover is not known at
this time, and may either be performed in a phased manner, or may be performed as
continuous placement of the cover over all of the tailings cells. If the final cover is
constructed in phases, verification testing will be performed for each portion of the
reclaimed tailings after each phase of construction. However, if construction of the final
cover is performed as a continuous placement of the cover over aii of the tailings cells,
verification testing will be conducted for the entire reclaimed tailings area at once, in
either scenario, verification testing for radon emanation will be performed as soon as
reasonably achievable after placement of the final cover. Results of the verification
testing will be reported within ninety days of the completion of all testing and anaiysis
relevant to the verification.
Please provide and submit to for the Division's review, once the final tailings cover system design for
Revision 4.0 of the Reclamation Plan has been fmalized, a map of the disposal cells area indicating
the proposed measurement locations for radon emissions verification testing and the outline of
tailings and the radon barrier cover extent Submittal of such an emissions measurement plan is in
conformance with guidance contained in NUREG 1620 (NRC 2003), Section 5.1.2.1. . The emission
measurement locations must conform to the requirements of Method 115 stated in Appendix B to 40
CFR 61 or a comparable method based on reasonable statistical evaluations of background radon
fiux measurements and must provide acceptable preliminary measurements of radon fiux on the
radon barrier, and the required confidence level (refer, for example, to the statistical development
defined in NUREG-1575 [NRC 2000] for sampling contaminated areas).
Response No. 3:
See Response No. 1,
Please provide detailed procedures for conducting radon fiux measurements and analyses. Address in
these procedures actions taken and restrictions imposed to ensure that flux measurements are not
falsely constrained by transient moisture content of the radon barrier or by failure for radon flux to
have equilibrated at the time of measurement.
Interrogatory 07/01:11 E.(2); 10CFR40, Appendix A, Criterion 6(2); 6(3); 6(4): Verify Effectiveness of Final Radon Barrier,
and Phased Emplacement of Final Radon Barrier, and Report Radon Banier Effectiveness Page 40 of 44
Response No. 4:
See Response No. 1. Measurement, calculation of radon fiux, and reporting wili aii be
performed in accordance with procedures described in 40 CFR Part 61, Appendix B,
Method 115
5. Please provide a plan detailing the method in which records will be maintained, the length of time
records will be maintained and include any associated methods utilized in the veriflcation of the
radon barrier effectiveness.
Response No. 5:
See Response No. 1. As stated in the Updated Tailings Cover Design Report, the
documentation of final cover verification will include the results of all measurements, the
calculations and/or anaiytical methods used to derive radon flux, and the procedure used
to determine compliance. These records wiil be maintained on site or at an off-site
storage facility until the time of site transfer to the DOE.
•1
BASIS FOR INTERROG A TORY:
Information regarding the sequencing and durations of reclamation activities, including for the tailings
cells area needs to be provided for flnal cover closure as a part of the revised Reclamation Plan. The
requirement to verify effectiveness of the cover system's radon barrier by reporting all testing, including
methods, analysis, time length and testing outcomes, also needs to be satisfled as soon as reasonably
achievable after emplacement of the flnal cover, as required by UAC R313-24-4 [10 CFR Part 40,
Appendix A, Criterion 6(2)] (see below), and as described in NUREG-1620 (NRC 2003), Section 5.1.2.1.
DUSA has provided information indicating that the final reclamation of the tailings cells is planned as a
phased approach. However, DUSA indicates that the timing of placement of the final cover over the
platform fill will be based on the physical condition of the tailings cell and management's decision on
overall long range mill operations and economics. However, the Reclamation Plan provides no clear
schedule for radon barrier placement (or subsequent verification testing). It is therefore unclear as to the
precise sequencing of radon barrier placement for the tailings cells area(s), i.e., placement in distinct
phases or placement as a fairly continuous operation, and the amount of lag time, if any, between
completion of any given phase of radon barrier placement or continuous radon barrier placement and
final verification testing of that placed material This uncertainty significantly complicates the cost
estimates for the surety.
Ifthe radon barrier layer is placed in phases, UAC R313-24-4 [10 CFR Part 40, Appendix A, Criterion
6(2)] specifies that, as soon as reasonably achievable after emplacement of the final cover over
dewatered tailings licensees need to verify through appropriate testing and analysis that the design and
constmction of the final radon barrier is effective in limiting releases of radon-222 to a level not
exceeding 20 pCi/m^s, averaged over the entire pile or impoundment using the procedures described in
40 CFR Part 61, Appendix B, Method 115, or another method of verification approved by the Executive
Secretary as being at least as effective in demonstrating the effectiveness of the final radon barrier.
NUREG 1620 (NRC 2003), Section 5.1.2.1 indicates that a measured (not calculated) disposal cell
average radon fiux is required by Appendix A, Criterion 6(2), as soon as practical after placement ofthe
radon barrier, and Criterion 6(3) stipulates that radon-222 release rates must be verified for each
portion of the pile or impoundment as the final radon barrier for that portion is placed, when phased
emplacement of the final radon barrier is included in a reclamation plan. This section of NUREG-1620
also specifies that the final radon barrier must be placed as expeditiously as practicable, and indicates
interrogatory 07/01:11E.(2); 10CFR40, Appendix A, Criterion 6(2); 6(3); 6(4): Verify Effectiveness of Final Radon Banier,
and Phased Emplacement of Final Radon Barrier, and Report Radon Banier Effectiveness Page 41 of 44
that a commitment to measure and document the radon fiux on the final radon barrier, as required by
Criterion 6(2) and (4), should be in the reclamation plan. (This section of the NRC document also
recommends that, before the measurements are performed, a map of the disposal cell indicating the
measurement locations and outline of tailings and cover extent should be prepared for review before the
measurements are performed. This map needs to be prepared and submitted as a part of the preliminary
decommissioning plan, mentioned above. .
NUREG-1620 (NRC 2003), Section 5.2.3 specifies that a Reclamation Plan should indicate the location
of records important to decommissioning procedures for protection of health and safety and demonstrate
that decommissioning will be completed as soon as practicable, as required by 10 CFR 40.42 and
Appendix A, Criterion 6A.
REFERENCES:
Nuclear Regulatory Commission (NRC) 2000. Multi-Agency Radiation Survey and Site Investigation
Manual (MARSSIM) (NUREG-1575, Revision 1). August 2000.
NRC 2003. NUREG-1620: Standard Review Plan for the Review of a Reclamation Plan for
Mill Tailings Sites Under Title II of the Uranium Mill Tailings Radiation Control Act of
1978. Washington DC, June 2003.
intenogatory 07/01:11E.(2); 10CFR40, Appendix A, Criterion 6(2); 6(3); 6(4): Verify Effectiveness of Final Radon Banier,
and Phased Emplacement of Final Radon Barrier, and Report Radon Banier Effectiveness Page 42 of 44
INTERROGATORY WHITE MESA RECPLAN 08/01: UAC R313-15-101; RADIATION
SAFETY CONTROLS AND MONITORING
REGULATORY BASIS:
UAC R313-15-101. Radiation Protection Prosrams. The Utah Uranium Mills and Source Material
Tailinss Disposal Facilitv mles [UAC R313-24-1 (3)1 requires that the provisions of UAC R315-15 applv
to these licensees. In tum. UAC R313-15-101 requires:
"(1) Each licensee or registrant shall develop, document, and implement a radiation protection
program sufficient to ensure compliance with the provisions of Rule R313-15. See Section R313-
15-1102 for recordkeeping requirements relating to these programs.
(2) The licensee or registrant shall use, to the extent practical procedures and engineering controls
based upon sound radiation protection principles to achieve occupational doses and doses to
members of the public that are as low as is reasonably achievable (.ALARA).
(3) The licensee or registrant shall, at intervals not to exceed 12 months, review the radiation
protection program content and implementation.
(4) To implement the ALARA requirements of Subsection R313-15-101(2), and notwithstanding the
requirements in Section R313-15-301, a constraint on air emissions of radioactive material to the
environment, excluding radon-222 and its decay products, shall be established by licensees or
registrants such that the individual member of the public likely to receive the highest dose will not
be expected to receive a total effective dose equivalent in excess of 0.1 mSv (0.01 rem) per year
from these emissions. Ifa licensee or registrant subject to this requirement exceeds this dose
constraint, the licensee or registrant shall report the exceedance as provided in Section R313-15-
1203 and promptly take appropriate corrective action to ensure against recurrence. "
INT ERR OGA TOR Y STA TEMENT:
1. Please revise the Reclamation Plan, Rev. 4.0 to address modifications to the radiation protection
program necessary to protect site workers, the public, and the environmental from any unique
radiation hazards and effects associated with reclamation and decommissioning activities. Such
revisions to the Reclamation Plan, Rev. 4.0 should address the following:
a. Identify the radiation safety concems that are unique to reclamation and decommissioning
activities. These concems include characterization of radiation hazards associated with
inhalation of resuspended tailings material or yellowcake, gamma exposure from working
close to tailings, and inhalation of radon gas and its progeny (decay products) emanating
from tailings material
b. Describe any changes to an existing radiation safety or monitoring program that would be
necessary to ensure worker or public safety during reclamation or decommissioning
activities.
c. Standard dust control measures such as regular wetting and/or phased stabilization to be
used to control windblown tailings material or yellowcake dust.
d. Any proposed changes to the established bioassay pro-am will meet criteria ofthe
applicable parts of Regulatory Guide 8.22, "Bioassay at Uranium Mills " and Regulatory
Guide 8.9, Revision 1, "Acceptable Concepts, Models, Equations, and Assumptions fora
Bioassay Program " (NRC, 1993), or an acceptable justification is provided for selecting an
alternate approach.
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e. Proposed workplace airbome radiological monitoring program that will support the
proposed bioassay program and is consistent with applicable parts of Regulatory Guide 8.25,
"Air Sampling in the Workplace" and Regulatory Guide 8.30, "Health Physics Surveys in
Uranium Mills, " or an acceptable justification for selecting an altemate approach, if
preferred. The monitoring program will provide adequate protection of workers from radon
gas or particulate exposures to maintain compliance with the inhalation limits in 10 CFR
Part 20. If sampling locations will be revised, the reclamation plan contains one or more
maps of the site that indicate the location of all samplers for airbome radiation and provide
the justification for determining the revised locations.
f. Proposed contamination control program consistent with the guidance on conducting surveys
for contamination of skin and ofpersonal clothing presented in Regulatory Guide 8.30.
g. Proposed environmental radiological monitoring program consistent with applicable parts of
Regulatory Guide 4.14, "Radiological Effiuent and Environmental Monitoring at Uranium
Mills ", or an acceptable justification if an alternate approach if proposed. Demonstrate that
site-specific aspects of climate and topography have been considered in determining
locations of off-site airborne monitoring stations and environmental sampling areas so that
detection of maximum off-site concentrations of windblown tailings material and
contamination from any other significant transport pathways applicable to the site is
ensured.
h. Proposed radiation protection program contains plans for documenting exposures to all
monitored workers and contractors and for availability of exposure records in a single
location for inspection. The program should provide for recordkeeping that meets the
requirements of 10 CFR 20.2102; at least annual review of the program content and
implementation; and implementation of the "as low as is reasonably achievable "
requirements of 20.1101 (d).
Response No. 1:
The information requested in this interrogatory is provided in the Radiation Protection
Manual for Reclamation (Attachment D of the 2011 Reclamation Plan).
BASIS FOR INTERROG A TORY:
DUSA should document revisions to the existing radiation protection program that are necessary to
accommodate and protect against the hazards unique to the reclamation and decommissioning ofthe mill
and associated facilities.
REFERENCES:
Denison Mines (USA) Corporation. 2009. Reclamation Plan, Revision 4.0, White Mesa Mill, Blanding,
Utah, November 2009.
Nuclear Regulatory Commission (NRC) 2003. NUREG-1620: Standard Review Plan for the Review of a
Reclamation Plan for Mill Tailings Sites Under Title II of the Uranium Mill Tailings Radiation
Control Act of1978. Washington DC, June 2003.
interrogatory 08/01: UAC R313-15-101; Radiation Safety Controls and Monitoring Page 44 of 44