DRC-2009-008035 - 0901a06880140983

Environmental Report In Support of Construction
Tailings Cell 4b
White Mesa Uranium Mill
Blanding,Utah
Prepared by Denison Mines (USA)Corp.
I050 1i h Street,Suite 950
Denver,Colorado 80265
April 30,2008
Introduction
Denison Mines (USA)Corp.is seeking an amendment to its'Radioactive Materials
License,No.UT1900479 in order to obtain UDEQ's approval to construct,operate and
(when operations are complete)reclaim a proposed new tailings impoundment at its
White Mesa Uranium Mill,Cell 4b.The construction of the Cell 4b is an essential
element of future operations at the White Mesa Mill as its construction is necessary in
order to continue providing sufficient impoundment surface area for the evaporation of
Mill processes water.This Cell also provides additional tailings capacity which is
necessary to accommodate the tailing volume associated with routine ore processing
operations.While the new cell has not yet been constructed,it was contemplated,
described and assessed previously,being a critical component of the initial 1978 NRC-
FEIS and attendant licensing of the facility.More specifically,the initial environmental
analysis and license application for the facility contemplated six tailing cells;operating
cells 1,2 and 3,as well as 3 additional 80 acre cells,Cells 4,5 and 6.With the
construction of Cell 4a (40 acres),Cell 4b will consume the second 40 acres of the
previously authorized 80 acre Cell 4.
The information required for an amendment to the Mill's Radioactive Materials License
is found at R313-24-3.More specifically,the regulations state the following:
(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 non-radiological impacts to the
public health from the activities to be conducted pursuant to the license or
amendment;
(b)An assessment of any impact on waterways and groundwater resulting
from the activities conducted pursuant to the license or amendment;
(c)Consideration of alternatives,including alternative sites and
engineering methods,to the activities to be conducted pursuant to the
license or amendment;
and
(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.
In order to fulfill the requirements above,Denison considered and used the information
topics and format cited by NRC in its guidance document NUREG 1359 for its recent
License Renewal Application.Because the Renewal Application provided current
environmental information and assessments,the scope of this Environmental Report can
be limited in some respects,focusing on pathways and assessments directly related to the
construction of the new tailings cell.Accordingly,topical headings suggested by
NUREG 1359 have been included in this document;however,where previously provided
information is sufficient and unaffected by this amendment request,the prior information
is incorporated by reference.Denison's assessment ofthe pathways to be considered for
construction of cell 4b is principally focused on the examination of potential airborne
releases from the pond and the groundwater considerations typically attendant to the
design of a tailing cell.It is important to note that UDEQ has approved the design and
construction of directly adjacent and nearly completed Cell 4a.The liner design and
underlying ground conditions for Cell 4b are identical to those ofCell 4a.
11
Table of Contents
Introduction 1
Table ofContents 111
Index ofFigures.iv
1.0 Site Location and Layout......................................................1
2.0 Climate and Meteorology...1
1.1 Regional Climate " .............................. 1
1.2 Onsite Monitoring Program ,.4
3.0 Use ofAdjacent Lands and Water......4
4.0 Population Distribution and Socioeconomic Profile.....6
5.0 Topography ;'...............................8
6.0 Geologic Setting.....................................................................8
6.1 Regional Geology............................................................ 8
6.2 Local Geology ,.9
6.3 Site-Specific Geologic Setting ,.9
7.0 Hydrologic Setting.................................................................12
7.1 Perched Zone Hydrogeology ,'"12
7.2 Perched Groundwater Flow.................................15
7.3 Perched Hydrogeology (Down-gradient ofTailings Cells............15
7.4 Groundwater Quality ,.19
8.0 Ecological Resources and Biota............23
8.1 TerrestriaL...................................................................23
8.2 Aquatic and Wetland Biota '"26
9.0 Background Radiological and Non-Radiological Characteristics..26
10.0 Environmental Effects Related Directly to the Construction ofCell 4b 26
10.1 Groundwater Pathway Impact.......27
10.2 Proposed Additional Groundwater Monitoring........................27
10.3 Radiological Impact Related Directly to the Construction ofCell 4b 28
10.4 Radiological Monitoring Assessment....................................30
11.0 Alternatives..........................................30
11.1 Issuance ofAmendment for Ce1l4b...31
11.2 No Action Alternative..........................................31
11.3 Alternatives Considered But Eliminated..................................32
11.4 Cumulative Effects.............................................................33
11.5 Comparison ofPredicted Environmental Impacts............33
11.6 Updates and Changes to Factors That May Cause Reconsideration of
Alternatives...................................................................33
12.0 Costs and Benefits...34
13.0 Mitigaiton ofImpacts.34
14.0 Long Tenn Impacts.....................................................35
Appendix A
Site Hydrogeology Estimation Of Groundwater Travel Times and Recommended
Additional Monitoring Wells For Proposed Tailings Ce1l4BWhite Mesa Uranium Mill
Site Near Blanding,Utah
111
Appendix B
Dose Assessment Pertaining to the Proposed Development ofNew Tailings Cells For the
White Mesa Uranium Mill,SENES Consultants,Hydro Geo Chern,Inc
Appendix C
Review ofEnvironmental Monitoring Program,SENES Consultants
Index of Figures
Figure
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Figure 11
Figure 12
Location Map White Mesa Mill
White Mesa Mill Land Map
White Mesa Wind Rose
Population in the Project Vicinity
Local Topography
Generalized Stratigraphy ofWhit Mesa Mill
Approximate Elevation Top ofBrushy Basin
Kriged 4th Quarter Water Levels
Approximate Location ofRuin Spring
Depth to Perched Water
Stock Watering Pond Locations
Reclamation Cover Grading Plan for Cell 4b
IV
2
3
5
7
9
10
13
16
17
18
20
36
1.0 Site Location and Layout
The Mill is regionally located in central San Juan County,Utah,approximately 6 miles (9.5 km)
south of the city of Blanding.The Mill can be reached by taking a private road for
approximately 0.5 miles west ofUtah State Highway 191.See Figure 1.
Within San Juan County,the Mill is located on fee land and mill site claims,covering
approximately 5,415 acres,encompassing all or part ofSections 21,22,27,28,29,32,and 33 of
T37S,R22E,and Sections 4,5,6,8,9,and 16 of T38S,R22E,Salt Lake Base and Meridian.
See Figure 2.
All operations authorized by the License are conducted within the confines of the existing site
boundary.The milling facility currently occupies approximately 50 acres and the current tailings
disposal cells encompass another 250 acres.See Figure 2.
The resident currently nearest to the milling facility is located approximately 1.2 miles (1.9 km)
north ofthe Mill site,just north ofair sampling station BHV-1.See Figure 2.
2.0 Climate and Meteorology
2.1 Regional Climate
The climate of southeastern Utah is classified as dry to arid continental.Although varying
somewhat with elevation and terrain,the climate in the vicinity ofthe Mill can be considered as
semi-arid with nOlma1 annual precipitation of about 13.4 inches.Most precipitation is in the
form ofrain with snowfall accounting for about 29%of the annual total precipitation.There are
two separate rainfall seasons in the region,the first in late summer and early autumn (August to
October)and the second during the winter months (December to March).The mean annual
relative humidity is about 44 percent and is normally highest in January and lowest in July.The
average annual Class A pan evaporation rate is 68 inches (National Oceanic and Atmospheric
Administration and U.S.Department of Commerce,1977),with the largest evaporation rate
typically occurring in July.This evaporation rate is not appropriate for determining water
balance requirements for the tailings management system and must be reduced by the Class A
pan coefficient to detelmine the later evaporation rate.Values of pan coefficients range from
60%to 81 %.Denison assumes for a water balance calculations an average value of 70%to
obtain an annual lake evaporation rate for the Mill area of47.6 inches.Given the annual average
precipitation rate of 13.4 inches,the net evaporation rate is 34.2 inches per year.
1
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White Mesa Mill
Location Map
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White Mesa Mill
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The weather in the Blanding area is typified by warm summers and cold winters.The mean
annual temperature in Blanding is about 50°(F).January is usually the coldest month and July is
usually the warmest month.
Winds are usually light to moderate in the area during all seasons,although occasional stronger
winds may occur in the late winter and spring.The predominant winds are from the north
through north-east (approximately 30 percent ofthe time)and from the south through south-west
(about 25 percent of the time).Winds are generally less than 15 mph,with wind speeds faster
than 25 mph occurring less than one percent of the time.The National Weather Service Station
in Blanding,Utah is located about 6.25 miles north of the Mill.Data from the station is
considered representative ofthe local weather conditions (1978 ER,Section 2.7.2).However,as
an element of the pre-construction baseline study and ongoing monitoring programs,the Mill
operates an onsite meteorological station,described in greater detail below.Further details about
weather and climate conditions are provided in the 1978 ER (Section 2.7)and in the FES
(Section 2.1).The 1978 ER and FEIS are resource documents,incorporated here by reference.
2.2 On Site Monitoring Program
On-site meteorological monitoring at the Mill was initiated in early 1977 and continues today.
The original purpose of the meteorological monitoring program was to document the regional
atmospheric baseline and to provide data to assist in assessing potential air quality and
radiological impacts arising from operation ofthe Mill.
After the Mill construction was completed,the monitoring programs were modified to facilitate
the assessment ofMill operations.The current meteorological monitoring program includes data
collection for wind speed,wind direction,atmospheric stability according to the standard
Pasquill scheme (via measurements of deviations in wind direction,referred to as sigma-theta),
and precipitation as either rain or snow.The recorded on-site meteorological conditions are
reported to Denison on a semi-annual basis and are described in semi-annual reports prepared for
Denison and maintained at the Mill.Figure 3 shows the windrose for the Mill site during the
period ofJanuary -December 2007,the most recent full year ofcompiled meteorological data.
3.0 Use ofAdjacent Lands and Water
Approximately 65.8%of San Juan County is federally owned land administered by the U.S.
Bureau of Land Management,the National Park Service,and the U.S.Forest Service.Primary
land uses include livestock grazing,wildlife range,recreation,and exploration for minerals,oil,
and gas.Approximately 22%of the county is Native American land owned either by the Navajo
Nation or the Ute Mountain Ute Tribe.The area within 5 miles of the Mill site is predominantly
range land owned by Blanding residents.The Mill site,including tailings cells,encompasses
approximately 300 acres.
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A more detailed discussion of land use at the Mill site,in surrounding areas,and in southeastern
Utah,is presented in the FES (Section 2.5).Results ofarcheological studies conducted at the site
and in the surrounding areas as part of the 1978 ER are also documented in the FES (Section
2.5.2.3).
4.0 Population Distribution and Socioeconomic Profile
Demographic information is generally derived from information obtained by the U.S.Census
Bureau.These records are updated on a five year frequency for population centers which exceed
65,000 people and on a ten year frequency for lesser populations.As such,the local population
update for the area of interest was last recorded in the year 2000,and it is that data base which
was utilized to formulate the demographic information provided in the recent license renewal
effort and this report.According to the 2000 census,the population density of San Juan County,
in which the Mill is located,is 1.8 individuals per square mile.By comparison,the statewide
density is greater than 27.2 persons per square mile.The town ofBlanding,Utah,approximately
6 miles north of the Mill,is the largest population center near the Mill site,with 3,162 persons.
Approximately 5 miles southeast of the Mill site is the White Mesa community,where
approximately 277 Ute Mountain Ute tribal members reside.See Figure 4.The Navajo
Reservation is located approximately 19 miles southeast of the Mill.The nearest community on
the Navajo Reservation is Montezuma Creek,a community of approximately 507 individuals in
Utah.The nearest resident to the Mill is located approximately 1.5 miles to the north ofthe Mill,
near air monitoring station BHV-1.
Table 1 provides population centers located within 50 miles of the Mill site.
Table I-Population Centers Within 50 Miles of the Mill Site
Population Center 2000 Population Distance From Sitel
(miles)
Blanding,UT 3,162 6
White Mesa,UT 277 4
Bluff,UT 320 15
Montezuma Creek,UT 507 20
Aneth,UT 598 27
Mexican Hat,UT 88 30
Monticello,UT 1,958 27
Eastland/Ucolo,UT 2495 32
Dove Creek,CO 698 37
Towaoc,CO 1,097 50
Source:http://factfinder.census.gov
I 2000 Census
2 Approproximatedistance from Mill siteby air
J Based on 1978 population estimate
San Juan County,Utah,is the largest and poorest county in Utah.As of December 2006,the
unemployment rate in San Juan County was 4.9%,compared to 2.6%for Utah as a whole,and
4.5%for the nation as a whole.When operating,the Mill is one of the largest private employers
in San Juan County,employing up to 60-140 full time employees.As
6
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Figure 4
Population in The Project Vicinity
2000 Census
such,the Mills employees represent a significant economic base for the city of Blanding and
rural residents of San Juan County.In addition,the Company pays local taxes to San Juan
County,further supporting the development of the local economic base.The Mill also provides
income to local minorities,typically employing a high percentage of minority workers ranging
from 45-75%Native Americans.
Since its inception in 1980,the Mill has run on a campaign basis,in each case remaining on
standby pending accumulation of sufficient ore stockpiles to justify a milling campaign.
Currently,Mill employees are predominantly residents of San Juan County,or residents of
neighboring counties who commute to the Mill on a daily basis.Historically,the Mill has drawn
upon such residents of San Juan County and neighboring counties for each milling campaign,
rather than relying upon an influx of workers to the area.As a result,Mill campaigns have not
given rise to any unusual demands on public services or resulted in any cultural or
socioeconomic issues for the surrounding areas.
5.0 Topography
The Mill site is located on a gently sloping mesa that,from the air,appears similar to a
peninsula,as it is surrounded by steep canyons and washes and is connected to the Abajo
Mountains to the north by a narrow neck of land.On the mesa,the topography is relatively flat,
sloping at less than one (1)percent to the south and nearly horizontal from east to west.See
Figure 5.
6.0 Geologic Setting
6.1 Regional Geology
The Mill site lies within a region designated as the Canyon Lands section of the Colorado
Plateau physiographic province.Elevations in the region range from approximately 3,000 feet in
the bottom of canyons to over 11,000 feet among the peaks of the Henry,Abajo and La Sal
Mountains.The average elevation for the area,excluding deeper canyons and isolated mountain
peaks,is about 5,000 feet.
The sedimentary rocks exposed in southeastern Utah have a total thickness of approximately
6,000 to 7,000 feet.These sedimentary units range in age from Pennsylvanian to Late
Cretaceous;older rock units which underlie those of Pennsylvanian age are not exposed in the
Mill site area.
Structural features in the Mill site area have been divided into three main categories on the basis
oforigin or mechanism ofthe stress that created the structure.These categories are:(1)structures
related to large-scale regional uplifting or downwarping directly related to movements in the
basement complex (the Monument Uplift and the Blanding Basin);(2)structures due to diapiric
deformation of thick sequences of evaporate deposits,salt plugs and salt anticlines (the Paradox
Fold and Fault Belt);and (3)structures formed due to magmatic intrusions (the Abajo
Mountains).A generalized stratigraphic column for the region is provided as Figure 6.
8
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Local Topography
And Location ofRuin Spring
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Denison Mines (USA)Corp
Figure 6
Generalized Stratigraphy of
\Vhite Mesa Mill
The Summerville Fonnation,Entrada Sandstone,and Navajo Sandstone are the deepest units of
concern encountered at the site.
6.2 Local Geology
The Mill site is located on the western edge of the Blanding Basin,sometimes referred to as the
Great Sage Plain,lying east of the north/south-trending Monument Uplift,south of the Abajo
Mountains and adjacent to the northwest-trending Paradox Fold and Fault Belt.The Abajo
Mountains are the most prominent topographic feature in the region,rising over 4,000 ft above
the surface of the plain.The lithology of the immediate area is composed of thousands offeet of
multi-colored pre-Tertiary age marine and non-marine sedimentary rocks.Erosion on the
regionally-uplifted sedimentary strata has produced an array of eroded canyons and mesas.
The Mill is more specifically located on White Mesa and rests on alluvial windblown silt and
sand which covers sandstones and shales of Jurassic and Cretaceous age.The surface ofthe mesa
is nearly flat,with a surface relief of 98 ft.The maximum relief between White Mesa and the
adjacent Cottonwood Canyon is about 750 ft.
6.3 Site-Specific Geologic Setting
The Mill is located within the Blanding Basin of the Colorado Plateau physiographic province.
Typical of large portions of the Colorado Plateau province,the rocks underlying the site are
relatively underfonned.The average elevation of the site is approximately 5,600 ft (1,707 m)
above mean sea level (amsl).
The site is underlain by unconsolidated alluvium and indurated sedimentary rocks consisting
primarily of sandstone and shale.The indurated rocks are relatively flat lying with dips
generally less than 30.The alluvial materials consist mostly of aeolian silts and fine-grained
aeolian sands with a thickness varying from a few feet to as much as 25 to 30 ft (7.6 to 9.1 m)
across the site.The alluvium is underlain by the Dakota Sandstone and Burro Canyon
Fonnation,which are sandstones having a total thickness ranging from approximately 100 to 140
ft (31 to 43 m).Beneath the Burro Canyon Fonnation lies the Morrison Fonnation,consisting,
in descending order,of the Brushy Basin Member,the Westwater Canyon Member,the
Recapture Member,and the Salt Wash Member.The Brushy Basin and Recapture Members of
the Morrison Fonnation,classified as shales,are very fine-grained and have a very low
penneability.The Westwater Canyon and Salt Wash Members also have a low average vertical
penneability due to the presence of interbedded shales.See Figure 6 for a generalized
stratigraphic column for the region.
Beneath the MOlTison Fonnation lies the Summerville Fonnation,an argillaceous sandstone with
interbedded shales,and the Entrada Sandstone.Beneath the Entrada lies the Navajo Sandstone.
The Navajo and Entrada Sandstones constitute the primary aquifer in the area of the site.The
Entrada and Navajo Sandstones are separated from the Burro Canyon Fonnation by
approximately 1,000 to 1,100 ft (305 to 335 m)of materials having a low average vertical
penneability.Groundwater within this system is under
11
artesian pressure in the vicinity ofthe site,and is used only as a secondary source of water at the
site.
7.0 Hydrogeologic Setting
The site is located within a region that has a dry to arid continental climate,with average annual
precipitation ofapproximately 13.4 in.Recharge to aquifers occurs primarily along the mountain
fronts (for example,the Henry,Abajo,and La Sal Mountains),and along the flanks of folds such
as Comb Ridge Monocline.
Although the water quality and productivity of the Navajo/Entrada aquifer are generally good,
the depth ofthe aquifer (approximately 1,200 ft below land surface (bls))makes access difficult.
The Navajo/Entrada aquifer is capable of yielding significant quantities of water to wells
(hundreds of gallons per minute (gpm)).Water in wells completed across these units at the site
rises approximately 800 ft above the base ofthe overlying Summerville Formation.
7.1 Perched Zone Hydrogeology
Perched groundwater beneath the site occurs primarily within the Burro Canyon Formation.
Perched groundwater at the site has a generally low quality due to high total dissolved solids
(TDS)in the range of 1,200 to 5,000 milligrams per liter (mg/L),and is used primarily for stock
watering and irrigation in the areas upgradient (north)ofthe site,The saturated thickness of the
perched water zone generally increases to the north of the site,increasing the yield of the
perched zone to wells installed north of the site.Perched water is supported within the Burro
Canyon Formation by the underlying,fine-grained Brushy Basin Member.Figure 7 is a contour
map showing the approximate elevation ofthe contact of the Burro Canyon Formation with the
Brushy Basin Member,which essentially forms the base of the perched water zone at the site.
Contact elevations are based on monitoring well drilling and geophysical logs and surveyed land
surface elevations.As indicated,the contact generally dips to the south/southwest beneath the
site.
The permeability of the Dakota Sandstone and Burro Canyon Formation at the site is generally
low.No significant joints or fractures within the Dakota Sandstone or Burro Canyon Formation
have been documented in any wells or borings installed across the site (Knight Piesold,1998).
Any fractures observed in cores collected from site borings are typically cemented,showing no
open space.
Based on samples collected during installation of wells MW-16 and MW-17 (the locations ofthe
various monitoring wells are indicated on Figure 7),located immediately downgradient of the
tailings cells at the site,porosities ofthe Dakota Sandstone range from 13.4%to 26%,averaging
20%,and water saturations range from 3.7%to 27.2%,averaging 13.5%.The average
volumetric water content is approximately 3%.The permeability ofthe Dakota Sandstone based
on packer tests in borings installed at the site ranges from 2.71E-06 centimeters per second
(cm/s)to 9.12E-04 cm/s,with a geometric average of3.89E-05 cm/s.
12
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EXPLANATION
MW-11 PERCHED MONITORING WELL5479SHOWINGAPPROXIMATEELEVATION OF BRUSHY BASIN CONTACT IN FEET AMSL
o 5536
~P-5
5552
TEMPORARY PERCHED MONITORING WELLSHOWINGAPPROXIMATEELEVATIONOFBRUSHY BASIN CONTACT IN FEET AMSL.
PIEZOMETERSHOWINGAPPROXIMATE ELEVATION OF BRUSHY BASIN CONTACT IN FEET AMSL
N
t
~CONTOUR LINE IN FEET AMSL,DASHED WHERE UNCERTAIN
/
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w WILDLIFE POND o 3000
SCAlE IN FEET
Denison Mines (USA)Corp
Figure 7
White Mesa Mill
Approximate Elevation
Top ofBrushy Basin
The average porosity of the Burro Canyon Formation is similar to that of the Dakota Sandstone.
Based on samples collected from the Burro Canyon Formation at MW-16,located immediately
downgradient of the tailings cells at the site,porosity ranges from 2%to 29.1%,averaging
18.3%,and water saturations of unsaturated materials range from 0.6%to 77.2%,averaging
23.4%.Titan,1994,reported that the hydraulic conductivity of the Burro Canyon Formation
ranges from 1.9E-07 to 1.6E-03 cmls,with a geometric mean of 1.1 E-05 cmls,based on the
results of 12 pumplrecovery tests performed in monitoring wells and 30 packer tests performed
in borings prior to that time.
Hydraulic testing of wells MW-l,MW-3,MW-5,MW-17,MW-18,MW-19,MW-20,and MW-
22 during the week of July 8,2002,yielded average perched zone permeabilities ranging from
approximately 4.0E-07 cmls to 5.0E-04 cmls,similar to the range reported by previous
investigators at the site (HGC,2002).Downgradient (south to southwest)of the tailings cells,
average perched zone permeabilities based on tests at MW-3,MW-5,MW-17, MW-20,and
MW-22 ranged from approximately 4.0E-07 to 4.0E-05 cm/s.Permeability estimates were based
on pumplrecovery and slug tests analyzed using several different methodologies.
A number of temporary monitoring wells have been installed at the site to investigate elevated
concentrations of chloroform initially discovered at well MW-4 in 1999.Some of the
conglomeratic zones encountered within the perched zone during installation of these wells are
believed to be partly continuous or at least associated with a relatively continuous zone ofhigher
permeability (IUSA and HGC,2001).The higher permeability zone defined by these wells is
generally located east to northeast of the tailings cells at the site,and is hydraulically cross-
gradient to upgradient of the tailings cells with respect to perched groundwater flow.Relatively
high permeabilities measured at MW-11,located on the southeastern margin ofthe downgradient
edge of tailings Cell 3,and at MW-14,located on the downgradient edge of tailings Cell 4,of
1.4E-03 cmls and 7.5E-04 cmls,respectively (UMETCO,1993),may indicate that this zone
extends beneath the southeastern margin ofthe cells.This zone ofhigher permeability within the
perched water zone does not appear to exist downgradient (south-southwest)ofthe tailings cells,
however.At depths beneath the perched water table,the zone is not evident in lithologic logs of
the southernmost temporary wells TW4-4 and TW4-6 (located east (cross-gradient)of Cell 3),
nor is it evident in wells MW-3,MW-5,MW-12,MW-15,MW-16,MW-17,MW-20,MW-21,
or MW-22,located south to southwest (downgradient)of the tailings cells,based on the
lithologic logs or hydraulic testing ofthe wells.
Because of the generally low permeability of the perched zone beneath the site,well yields are
typically low (less than 0.5 gpm),although yields of about 2 gpm may be possible in wells
intercepting the higher permeability zones on the east side of the site.Sufficient productivity
can,in general,only be obtained in areas where the saturated thickness is greater,which is the
primary reason that the perched zone has been used on a limited basis as a water supply to the
north (upgradient)ofthe site.
14
7.2 Perched Groundwater Flow
Perched groundwater flow at the site is generally to the south/southwest.Figure 8 displays the
local perched groundwater elevation contours at the Mill.As indicated,the perched groundwater
gradient changes from generally southwesterly in the western portion of the site to generally
southerly in the eastern portion ofthe site.
Perched water discharges in springs and seeps along Westwater Creek Canyon and Cottonwood
Canyon to the west-southwest of the site,and along Corral Canyon to the east of the site,where
the Burro Canyon Formation outcrops.Perched water flowing beneath the tailings cells
eventually discharges in springs and seeps located in Westwater Canyon,to the south-southwest
of the cells.The primary discharge point for perched water flowing beneath the tailings cells is
believed to be Ruin Spring,located approximately 10,000 ft south-southwest of the Mill site,as
shown in Figure 9.
7.3 Perched Zone Hydrogeology
(Beneath and Down-gradient Ofthe Tailings Cells)
As of the 4th Quarter,2006,perched water has been encountered at depths of approximately 50
to 115 ft bls in the vicinity of the tailings cells at the site (Figure 10).Beneath tailings Cell 3,
depths to water ranged from approximately 72 ft below top of casing (btoc)east of the cell (at
MW-3l),to approximately 115 ft btoc at the southwest margin of the cell (at MW-23).
Assuming an average depth ofthe base oftailings Cell 3 of 25 ft below grade,this corresponds
to perched water depths of approximately 47 to 90 ft below the base of the cell,or an average
depth ofapproximately 70 feet beneath the base ofthe cell.
The saturated thickness of the perched zone as of the 4th Quarter,2006 ranged from
approximately 94 ft in the northeast portion ofthe site to less than 5 ft in the southwest portion of
the site.Beneath tailings Cell 3,the saturated thickness varies from approximately 49 ft in the
easternmost comer ofthe cell to approximately 6 ft in the westernmost comer ofthe cell.South-
southwest of the tailings cells,the saturated thickness ranges from less than 1 ft at MW-21 to
approximately 25 ft at MW-17.The average saturated thickness south-southwest of the tailings
cells,based on measurements at MW-3,MW-5,MW-12,MW-14,MW-15,MW-17,and MW-
20,is approximately 14 ft.The average saturated thickness based on measurements at MW-5,
MW-15,MW-3,and MW-20,which lay close to a line between the center oftailings Cell 3 and
Ruin Spring,is approximately 12 ft.By projecting conditions at these wells,the average
saturated thickness is estimated to be approximately 10 to 15 ft between MW-20 and Ruin
Spring.
15
Fig.8
PROPERTy
BOUNDARY
MW·22-es450
548°_____
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/'.,//
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Figure 8
Kriged 4th Quarter,2007 Water Levels
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NOTES;Locations and elevations for TW4·23. TW4·24.and TW4·25 are approximate;
Water level for TW4·&is from the third quarter,2007
3000
MW-G371
MW·20es461
,/
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SCALE IN FEET
EXPLANATION
perched monitoringwell showing
elevation infeet amsl
temporary perchedmonitoring well
showing elevation in feet amsl
perched piezometer showing
elevation in feet amsl
perched monitoringwell installed April,2005
showing elevation in feet amsl
temporary perched monitoring well installed
April,2005 showing elevation in feet amsl
temporary perched monitoringwell installed
May,2007 showingapproximate elevation
-:::--:::-
I/f
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o 84
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PIEZOMETER
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WILDLIFE POND
o
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3000
SCALE IN FEET
Denison Mines (USA)Corp.
Figure 10
White Mesa Mill
Depth to Perched Water
September,2002
Perched zone hydraulic gradients currently range from a maximum of approximately 0.04 feet
per foot (ft/ft)immediately northeast oftailings Cell 3 to less than 0.01 ft/ft downgradient ofCell
3,between Cell 3 and MW-20.The average hydraulic gradient between the downgradient edge
of tailings Cell 3 and Ruin Spring was approximated by HGC to be approximately 0.012 ft/ft.
HGC also estimated a hypothetical worst case average perched zone hydraulic gradient,
assuming the perched water elevation to be coincident with the base of tailings Cell 3,to be
approximately 0.019 ft/ft.See Section 3.2 ofAppendix A.
HGC also estimated the average permeability ofthe perched zone downgradient of tailings Cell
3,based on pump/recovery test and slug test data obtained from perched zone wells located
along the downgradient edge of and south of Cell 3,to be between 2.39E-05 cm/s and 4.3E-05
cm/s.See Section 3.3 of Appendix A to the February 28,2007 Environmental RepOli
incorporated here by reference.
7.4 Groundwater Quality
7.4.1 Entrada/Navajo Aquifer
The Entrada and Navajo Sandstones are prolific aquifers beneath and in the vicinity of the site.
Water wells at the site are screened in both of these units,and therefore,for the purposes of this
discussion,they will be treated as a single aquifer.Water in the Entrada/Navajo Aquifer is under
artesian pressure,rising 800 to 900 ft above the top of the Entrada's contact with the overlying
Summervillle Formation;static water levels are 390 to 500 ft below ground surface.
Within the region,this aquifer is capable ofyielding domestic quality water at rates of 150 to 225
gpm,and for that reason,it serves as a secondary source ofwater for the Mill.Additionally,two
domestic water supply wells drawing from the Entrada/Navajo Aquifer are located 4.5 miles
southeast of the Mill site on the Ute Mountain Ute Reservation.Although the water quality and
productivity ofthe Navajo/Entrada aquifer are generally good,the depth ofthe aquifer (>1,000 ft
bls)makes access difficult.
Table 2 is a tabulation of groundwater quality of the Navajo Sandstone aquifer as reported in the
FES and subsequent sampling.The total dissolved solids (TDS)range from 244 to 1,110
mg/liter in three samples taken over a period from January 27,1977,to May 4,1977.High iron
(0.057 mg/liter)concentrations are found in the Navajo Sandstone.Because the Navajo
Sandstone aquifer is isolated from the perched groundwater zone by approximately 1,000 to
1,100 ft of materials having a low average vertical permeability,sampling of the Navajo
Sandstone is not required under the Mill's previous NRC Point of Compliance monitoring
program or under the state's GWDP.However,samples were taken at two other deep aquifer
wells (#2 and #5)on site (See Figure 11 for the locations of these wells),on June 1,1999 and
June 8,1999,respectively,and the results are included in Table 2.
19
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84
MW-12
109
MW-2 •
110
32
PROPERTY
BOUNDARY
•
•MW-20
79
EXPLANATION
•MW-11 PERCHED MONITORING WELL
97 SHOWING DEPTH TO WATER IN FEET STOC
T388
4
MW-22 •
70
;-
NOTE:DATA FOR PIEZOMETERS
ARE FROM AUGUST,2002
o 84
'iI)P-5
52
W
TEMPORARY PERCHED MONITORING WELL
SHOWING DEPTH TO WATER IN FEET STOC
PIEZOMETER
SHOWING DEPTH TO WATER IN FEET STOC
WILDLIFE POND
o
N
t
3000
SCALE IN FEET
Denison Mines (USA)Corp.
Figure 11
White Mesa Mill
Stock Watering Pond Locations
Table 2
Water Quality of Groundwater in the Mill Vicinity
FES,Test Well Well #2 Well #5Parameter(G2R)6/011991 6/08/991
(1/27/77 -3/23/781)
Field Specific Conductivity 310 to 400(umhos/cm)
Field pH 6.9 to 7.6
Temperature eC)11 to 22
Estimated Flow m/hr (gpm)109(20)
pH 7.9 to 8.16
Determination,mglliter
TDS (\a}180°C)216toll10
Redox Potential 211 to 220
Alkalinity (as CaCOS3)180 to 224
Hardness,total (as CaC03)177 to 208
Bicarbonate 226 214
Carbonate (as C03)0.0 <1.0 <1.0
Aluminum 0.003 0.058
Aluminum,dissolved <0.1
Ammonia (as N)0.0 to 0.16 <0.05 <0.05
Antimony <0.001 <0.001
Arsenic,total .007 to 0.014 0.018 <0.001
Barium,total 0.0 to 0.15 0.119 0.005
Beryllium <0.001 <0.001
Boron,total <0.1 to 0.11
Cadmium,total <0.005 to 0.0 <0.001 0.018
Calcium 50.6 39.8
Calcium,dissolved 51 to 112
Chloride 0.0 to 50 <1.0 2.3
Sodium 7.3 9.8
Sodium,dissolved 5.3 to 23
Silver <0.001 <0.001
Silver,dissolved <0.002 to 0.0
Sulfate 28.8 23.6
Sulfate,dissolved (as S04)17 to 83
Vanadium 0.003 0.003
Vanadium,dissolved <.002 to 0.16
Manganese 0.011 0.032
Manganese,dissolved 0.03 to 0.020
Chromium,total 0.02 to 0.0 0.005 0.005
Copper,total 0.005 to 0.0 0.002 0.086
Fluoride 0.18 0.18
Fluoride,dissolved 0.1 to 0.22
Iron,total 0.35 to 2.1 0.43 0.20
Iron,dissolved 0.30 to 2.3
1 Zero values (0.0)are below detection limits.
21
FES,Test Well Well #2 Well #5Parameter(G2R)6/011991 6/08/991
(1127/77 -3/23/781)
Lead,total 0.02 -0.0 <0.001 0.018
Magnesium 20.4 21.3
Magnesium,dissolved 15 to 21
Mercury,total <.00002 to 0.0 <0.001 <0.001
Molybdenum 0.001 <0.001
Molybdenum,dissolved 0.004 to 0.010
Nickel <0.001 0.004
Nitrate +Nitrate as N <0.10 <0.10
Nitrate (as N)<.05 to 0.12
Phosphorus,total (as P)<0.01 to 0.03
Potassium 3.1 3.3
Potassium,dissolved 2.4 to 3.2
Selenium <0.001 <0.001
Selenium,dissolved <.005 to 0.0
Silica,dissolved (as SiOz)5.8 to 12
Strontium,total (as U)0.5 to 0.67
Thallium <0.001 <0.001
Uranium,total (as U)<.002 to 0.16 0.0007 0.0042
Uranium,dissolved (as U)<.002 to 0.031
Zinc 0.010 0.126
Zinc,dissolved 0.007 to 0.39
Total Organic Carbon 1.1 to 16
Chemical Oxygen Demand <1 to 66
Oil and Grease 1
Total Suspended Solids 6 to 1940 <1.0 10.4
Turbidity 5.56 19.1
Determination (pCilliter)
Gross Alpha <1.0
Gross Alpha +precision 1.6+1.3 to 10.2+2.6
Gross Beta <2.0
Gross Beta +precision 8+8 to 73+19
Radium 226 +precision 0.3+0.2
Radium 228 <1.0
Ra-226 +precision 0.1 +.3 to 0.6+0.4
Th-230 +precision 0.1+0.4 to 0.7+2.7
Pb-210 +precision 0.0+4.0 to 1.0+2.0
Po-21O +precision 0.0+0.3 to 0.0+0.8
Source:Adapted from FES Table 2.25 with additional Mill sampling data
7.4.2 Perched Groundwater Zone
Perched groundwater in the Dakota/Burro Canyon Formation is used on a limited basis to the
north (upgradient)of the site because it is more easily accessible.The quality of the Burro
Canyon perched water beneath and downgradient from the site is poor and extremely variable.
The concentrations of total dissolved solids (TDS)measured in water sampled from upgradient
and downgradient wells range between approximately 1,200 and 5,000 mg/l.Sulfate
concentrations measured in three upgradient wells varied between 670 and 1,740 mg/l (Titan,
1994).The perched groundwater therefore is used primarily for stock watering and irrigation.
22
The saturated thickness of the perched water zone generally increases to the north of the site.
See the Background Groundwater Quality Report:Existing Wells For Denison Mines (USA)
Corp.'s White Mesa Mill Site,San Juan County,Utah dated December 2006 prepared by Intera,
Inc.,Appendix B.
At the time of renewal of the Mill license by the NRC in March,1997 and up until issuance of
the Mill's Groundwater Discharge Permit ("GWDP")in March 2005,the Mill implemented a
groundwater detection monitoring program to ensure compliance to 10 CFR Part 40,Appendix
A,in accordance with the provisions of Mill License condition 11.3A.The detection monitoring
program was in accordance with the report entitled,"Points of Compliance,White Mesa
Uranium Mill,"submitted by letter to the NRC dated October 5,1994.Under that program,the
Mill sampled monitoring wells MW-5,MW-ll,MW-12,MW-14,MW-15 and MW-17,on a
quarterly basis.Samples were analyzed for chloride,potassium,nickel and uranium,and the
results of such sampling were included in the Mill's Semi-Annual Effluent Monitoring Reports
that were filed with the NRC up until August 2004 and with the DRC subsequent thereto.
Prior to 1997,commencing in 1979,the Mill monitored up to 20 constituents in up to 13 wells.
That program was changed to the Points ofCompliance Program in 1997 because:
•The Mill and tailings system had produced no impacts to the perched zone or deep
aquifer;and
•The most dependable indicators of water quality and potential cell failure were
considered to be chloride,nickel,potassium and natural uranium.
8.0 Ecological Resources and Biota
8.1 Terrestrial
a)Flora
The natural vegetation presently occurring within a 25-mile (40-krn)radius of the Mill site is
very similar to that of the region,being characterized by pinyon-juniper woodland intergrading
with big sagebrush (Artemisia tridentata)communities.The pinyon-juniper community is
dominated by Utah juniper (Juniperus osteosperma)with occurrences of pinyon pine (Pinus
edulis)as a codominant or subdominant tree species.The understory of this community,which
is usually quite open,is composed of grasses,forbs,and shrubs that are also found in the big
sagebrush communities.Common associates include galleta grass (Hilaria jamesii),green
ephedra (Ephedra viridis),and broom snakewood (Gutierrezia sarothrae).The big sagebrush
communities occur in deep,well-drained soils on flat terrain,whereas the pinyon-juniper
woodland is usually found on shallow rocky soil of exposed canyon ridges and slopes.See
Section 2.9 of the 1978 ER.
Based on the work completed by Dames &Moore in the 1978 ER,no designated or proposed
endangered plant species occur on or near the project site (1978 ER,Section 2.8.2.1).Ofthe 65
proposed endangered species in Utah at that time,six have documented distributions in San Juan
23
County.A careful review of the habitat requirements and known distributions of these species
by Dames &Moore in the 1978 ER indicated that,because of the disturbed environment,these
species would probably not occur on the project site.The Navajo Sedge has been added to the
list as a threatened species since the Dames &Moore study.
In completing the 2002 EA,NRC staffcontacted wildlife biologists from the BLM and the Utah
Wildlife Service to gather local information on the occurrences of additional species surrounding
the Mill.In the 2002 EA,NRC staff concluded that the Navajo Sedge has not been observed in
the area surrounding Blanding,and is typically found in areas ofmoisture (2002 EA at 4).
b)Fauna
Wildlife data were collected by Dames &Moore through four seasons at several locations on the
Mill site,prior to construction of the Mill.The presence of a species was based on direct
observations,trappings and signs such as the occurrence of scat,tracks,or burrows.A total of
174 vertebrate species potentially occur within the vicinity of the Mill (1978 ER,Appendix D),
78 ofwhich were confirmed (1978 ER,Section 2.8.2.2).
Although seven species of amphibians are thought to occur in the area,the scarcity of surface
water limits the use of the site by amphibians.Eleven species of lizards and five snakes
potentially occur in the area (1978 ER,Section 2.8.2.2).
Fifty-six species ofbirds were observed in the vicinity ofthe Mill site (1978 ER,Section
2.8.2.2).
The food habits of eagles vary depending on the season and the region in which they live.Fish,
carrion and waterfowl such as mallard,are consumed by eagles when available to them.The
FES indicates that mallards are both common and permanent in the vicinity of the Mill (FES,
Table 2.28).
Raptors are prominent in the western United States.Five species were observed in the vicinity
of the site.Although no nests ofthese species were located at the time ofthe FES,all (except the
golden eagle,Aquila chrysaetos)have suitable nesting habitat in the vicinity ofthe site.The nest
of a prairie falcon (Falco mexicanus)was found about 3/4 mile (1.2 km)east of the site.
Although no sightings were made of this species,members tend to return to the same nests for
several years if undisturbed (1978 ER,Section 2.8.2.2).
Of several mammals that occupy the site,mule deer (Odocoileus hemionus)is the largest
species.The deer inhabit the project vicinity and adjacent canyons during winter to feed on the
sagebrush and have been observed migrating through the site to Murphy Point (1978 ER,Section
2.8.2.2).Winter deer use of the project vicinity,as measured by browse utilization,is among the
heaviest in southeastern Utah at 25 days ofuse per acre in the pinyon-juniper-sagebrush habitats
in the vicinity of the project site.In addition,this area is heavily used as a migration route by
deer traveling to Murphy Point to winter.Daily movement during winter periods by deer
inhabiting the area has also been observed between Westwater Creek and Murphy Point.The
present size ofthe local deer herd is not known.
24
Other mammals present at the site include the coyote (Canis latrans),red fox (Vulpes vulpes),
gray fox (Urocyon cineroargenteus),striped skunk (Mephitis mephitis),badger (taxidea taxus),
longtail weasel (Mustela frenata),and bobcat (Lynx rufus).Nine species ofrodents were trapped
or observed on the site,the deer mouse (Peromyscus maniculatus)having the greatest
distribution and abundance.Although desert cottontails (Sylvilagus auduboni)were uncommon
in 1977,black-tailed jackrabbits (Lepus califomicus)were seen during all seasons.
In the 2002 EA,NRC staff noted that,in the vicinity of the site,the U.S.Fish and Wildlife
Service had provided the list set out in Table 3.12-1,of the endangered,threatened,and
candidate species that may occur in the area around the site.
Table 3 Endangered,Threatened and Candidate Species in the Mill Area
Common Name Scientific Name Status
Navajo Sedge Carex specuicola Threatened
Bonytail Chub Gila elegans Endangered
Colorado Pikeminnow Ptychocheilus lucius Endangered
Humpback Chub Gila cypha Endangered
Razorback Sucker Xyrauchen texanus Endangered
Bald Eagle Haliaeetus leucocephalus Threatened
California Condor Gymnogyps californianus Endangered
Gunnison Sage Grouse Centrocercus minimus Candidate
Mexican Spotted Owl Strix occidentalis lucida Threatened
Southwestern Willow Flycatcher Empidonax traillii extimus Endangered
Western Yellow-billed Cuckoo Coccyzus americanus occidentalis Candidate
Black-footed Ferret Mustela nigripes Endangered
Source:2002 EA
The 2002 EA also noted that,in addition,the species listed on Table 3.12-2 may occur within the
Mill area that are managed under Conservation Agreements/Strategies
Table 4
Species Managed Under Conservation Agreements/Strategies at the Mill Area
Common Name Scientific Name
Colorado River Cutthroat Trout Oncorhynchus clarki pleuriticus
Gunnison Sage Grouse Centrocercus minimus
Source:2002 EA
For the 2002 EA,NRC staff contacted wildlife biologists from the BLM and the Utah Wildlife
Service to gather local information on the occurrences of these additional species surrounding
the Mill.NRC staff made the following conclusions (2002 EA p.4):
While the ranges of the bald eagle,peregrine falcon,and willow flycatcher encompass the
project area,their likelihood of utilizing the site is extremely low.The black-footed ferret has
not been seen in Utah since 1952,and is not expected to occur any longer in the area.The
25
California Condor has only rarely been spotted in the area of Moab,Utah,(70 miles north)and
around Lake Powell (approximately 50 miles south).The Mexican Spotted Owl is only found in
the mountains in Utah,and is not expected to be on the Mesa.The Southwestern Willow
Flycatcher,Western Yellow-billed Cuckoo,and Gunnison Sage Grouse are also not expected to
be found in the immediate area around the Mill site.
8.2 Aquatic and Wetlands Biota
Aquatic habitat at the Mill site ranges temporally from extremely limited to nonexistent due to
the aridity,topography and soil characteristics of the region and consequent dearth of perennial
surface water.Two small stockwatering ponds are located on the Mill site a few hundred yards
from the ore pad area (See Figure 11).One additional small "wildlife pond",east of Cell 4A,
was completed in 1994 to serve as a diversionary feature for migrating waterfowl.Although
more properly considered features of the terrestrial environment,these ponds essentially
represent the total aquatic habitat on the Mill site.These ponds probably harbor algae,insects,
other invertebrate forms,and amphibians.They also provide a water source for small mammals
and birds.Similar ephemeral catch and seepage basins are typical and numerous to the northeast
ofthe Mill site and south of Blanding.
Aquatic habitat in the Mill vicinity is similarly limited.The three adjacent streams (Corral
Creek,Westwater Creek,and an unnamed arm of Cottonwood Wash)are only intermittently
active,carrying water primarily in the spring during increased rainfall and snowmelt runoff,in
the autumn,and briefly during localized but intense electrical storms.Intermittent water flow
most typically occurs in April,August,and October in those streams.Again,due to the
temporary nature of these steams,their contribution to the aquatic habitat of the region is
probably limited to providing a water source for wildlife and a temporary habitat for insect and
amphibian species.
In the 2002 EA,NRC staffconcluded that (p.4)no populations offish are present on the project
site,nor are any known to exist in the immediate area ofthe site.Four species of fish designated
as endangered or threatened (the Bonytail Chub,Colorado Pikeminnow,Humpback Chub and
Razorback Sucker)occur in the San Juan River 18 miles south of the site,which Dames &
Moore noted in the 1978 ER (Section 2.8.2)is the closest habitat suitable for these species.NRC
staff further concluded that there are no discharges of mill effluents to surface waters,and
therefore,no impacts are expected for the San Juan River due to operations ofthe Mill.
9.0 Background Radiological and Non-Radiological Characteristics
Background Radiological and Non-Radiological Effects have been evaluated,updated and
reported extensively in Denison's February 28,2007 License Renewal Application and
accompanying Environmental Report,incorporated here by reference.
10.0 Environmental Effects Related Directly to the Construction of Ce1l4b
The environmental effects of Cell 4b construction consist of those related to the release of
airborne particulate (dusting),radon release from the operating cell,and the impact,if any,on
26
groundwater beneath the pond.In order to evaluate these environmental considerations two
separate evaluations were completed,Site Hydrogeology Estimation Of Groundwater Travel
Times and Recommended Additional Monitoring Wells For Proposed Tailings Cell 4BWhite
Mesa Uranium Mill Site Near Blanding,Utah,Hydro Geo Chem,Inc.,2008 and Dose
Assessment Pertaining to the Proposed Development ofNew Tailings Cells For the White Mesa
Uranium Mill,SENES Consultants,Ltd,2008.
These evaluations are provided as Appendix A and Appendix B,respectively,and are discussed
in summary in the pertinent subsections below.
10.1 Groundwater Pathway Impact
The evaluation provided by Hydro Geo Chern Inc.finds that travel time for any water exiting the
pond to the perched water zone and then to the point(s)of perched zone discharge is very long,
far exceeding the time period of milling operations and closure of the tailings cells when little
free liquid is available for infiltration through the cell liner system.More specifically,HGC
found that the time for fluids that could be released from the cells to reach the points of seepage
and spring formation at ruin spring and Cottonwood seep are on the order of several thousand
years.However,this analysis is very conservative in that travel time through the pond liner was
not considered,and because the liner system is robust state-of-the art construction,travel time
through the liner is a significant protective factor.In fact,this aspect has been evaluated
extensively by MWH Americas,Inc.in their report Infiltration and Contaminant Transport
Modeling Report,White Mesa Mill Site,Blanding Utah,November,2007,incorporated here by
reference.The infiltration modeling effort revealed that the construction design for Cells 4a
and 4b will meet the "Closed Cell Performance Requirements"of the Groundwater Discharge
Permit at Part I.D.6.More specifically,MWH concluded that the approved reclamation plan for
the cells will meet the following regulatory requirements for a period ofnot less than 200 years:
a)Minimize infiltration of precipitation or other surface water into the tailings,
including but not limited to the radon barrier;
b)Prevent the accumulation of leachate head within the tailings waste layer that
could rise above or over-top the maximum FML liner elevation internal to any
disposal cell,i.e.create a "bathtub"effect;and,
c)Ensure that groundwater quality at the compliance monitoring wells does not
exceed Ground Water Quality Standards or Ground Water Compliance Limits
specified in Part I.C.l and Table 2 ofthe Permit.
10.2 Proposed Additional Groundwater Monitoring
In order to monitor the performance of Cell 4b,and consistent with EPA Guidance,it was
concluded by Hydro Geo Chern Inc.that an additional well or wells will be needed to monitor
the Cell's performance at the downgradient edge of the cell.This in addition to the many wells
already incorporated into the Groundwater Discharge Permit for the facility.Accordingly,two
additional wells are proposed,one at the southwest comer of proposed Cell 4b and one between
the southwest comer well and existing well MW-15 (See Figure 10 of Appendix B.These
27
installations will conservatively maintain the approximate existing spacing as defined by the
proximity ofMW-14 to MW-15 along the downgradient edge ofexisting Cell 4a.
10.3 Radiological Impact
In February 2007,a dose assessment was prepared for DUSA by SENES Consultants,Ltd.in
support of the license renewal application for the mill.MILDOS-AREA was used to estimate
the dose commitments that could potentially be received by individuals and the general
population within a 50 mile (80 km)radius for processing of conventional ores.The assessment
was prepared for scenarios in which Colorado Plateau (0.25%U30 S and 1.5%V20 S)or Arizona
Strip (0.637%)ores are processed at the mill.
In order to evaluate the radiological impact of Cell 4b's operation the prior dose assessment
analyses was extended from the previous report of February 2007 to incorporate the dose from
the proposed development of new tailings cells anticipated in the future.The results of this
extended assessment are provided as Attachment B to this report (Proposed Development ofNew
Tailings cells For The White Mesa Uranium Mill,SENES,2008),and reveal that the addition of
Cell 4b to the facility will not impact the ability of the facility to comply with regulatory
requirements
The U.S.NRC approved MILDOS-AREA was used to estimate the dose commitments received
by individuals and the general population within a 50 mile (80 km)radius of the site for the
processing of either Colorado Plateau or Arizona Strip ore separately.In each scenario,the
doses arising from emissions of dust and radon from the mill area and ore pads were assumed to
be the same as the previous 2007 report since the scenarios both involve the processing of
Colorado Plateau and Arizona Strip ores.Therefore,MILDOS-AREA runs from the previous
report were revised to exclude the tailings cells.The doses from the tailings cells were estimated
in separate MILDOS-AREA runs and added to the dose from the mill area and ore pads.Table 4
provides a summary of the source terms included in Phases 1 and 2 of the development of new
tailings cells including Cells 4a and 4b.
TABLE 4
SOURCE TERMS INCLUDED IN PHASE 1 AND 2
Source Term Phase 1 Phase 2
Mill area included included
Ore Pads included included
Tailings Cell 2 with Interim Soil Cover included included
Tailings Cell 3 active interim soil cover
Tailings Cell 4A active active
Tailings Cell 4B excluded active
28
The wind erosion and radon release rates from the tailings cells (active and with interim
soil cover)were modeled by using a maximal worst case approach.
Each active tailings cell was modeled to have an active area of 10 acres (i.e.,the
maximum expected to be uncovered at any time since it is not possible to predict the
distribution ofuncovered tailings between the active cells at any given time.The release
rate of wind-eroded tailings dust was estimated for 10 acres.The total annual radon
release rate was estimated by assuming a radon release rate of20 pCi/m2s (i.e.,maximum
radon-222 emissions to ambient air from an existing uranium mill pile)over the entire
area of each cell consistent with NESHAPs.
Emissions from the tailings cells (2 and 3)with interim soil cover were assumed to occur
over the entire area of each cell;however,only radon is released at a rate of 10 pCi/m2s
after the application ofthe soil cover.
The calculated total annual effective dose commitments (including radon)calculated
using MILDOS-AREA were compared to the Utah Administrative Code R313-15-
301(1)(a)requirement that the dose to individual members of the public shall not exceed
100 mrem/yr (radon included).For proposed development of new tailings cells for the
processing of Colorado Plateau ore,the maximum total annual effective dose
commitments was calculated to be a maximum of 1.4 mrem/yr for an infant at the nearest
potential resident,BHV-1 (Tables 6.1-1 and 6.1-3)(i.e.,effective dose)and is about 1.4%
ofthe R313-15-301(1)(a)limit of 100 mrem/yr (radon included)to an individual member
of the public for Phases 1 and 2.For proposed development of new tailings cell for the
processing of Arizona Strip ore,the total annual effective dose commitments were
calculated to be a maximum of3.1 mrem/yr for an infant at the nearest potential resident,
BHV-1 (i.e.,effective dose)and is about 3.1 %of the 100 mrem/yr limit (radon included)
to an individual member ofthe public for Phases 1 and 2.Overall,the predicted annual
effective dose commitments for proposed development of new tailings cells during
anticipated ore processing operations comply with R313-15.
In addition,our MILDOS-AREA calculated 40 CFR 190 annual dose commitments
(excluding radon)were compared to the 40 CFR 190 criterion,which is 25 mrem/yr to
the whole body (excluding the dose due to radon)and 25 mrem/yr to any other organ to
any member of the public (U.S.EPA 2002).The 40 CFR 190 doses were also used to
demonstrate compliance with R313-15-101(4)(10 CFR 20.1101(d»(i.e.,the licensee
must demonstrate that total effective dose equivalent to the individual member of the
public likely to receive the highest total effective dose equivalent will not exceed 10
mrem/yr (absent of the radon dose).For proposed development ofnew tailings cells for
the processing of Colorado Plateau ore,the 40 CFR 190 annual dose commitments were
29
calculated to be a maximum of4.8 mrem/yr for a teenage at the nearest potential resident,
BHV-l (i.e.,dose to the bone)and is about 19%of the 40 CFR 190 dose criterion of25
mrem/yr for Phases 1 and 2.Further,the 40 CFR 190 annual effective dose
commitments demonstrate compliance with the R3l3-15-10l(4)(10 CFR 20.1101(d»
limit of 10 mrem/yr to the individual member of the public likely to receive the highest
total effective dose equivalent.For Arizona Strip ore,the 40 CFR 190 annual dose
commitments were at most 12 mrem/yr for a teenage at the nearest potential resident,
BHV-1 (i.e.,dose to the bone)and is well within the 40 CFR 190 dose criterion of 25
mrem/yr for Phases 1 and 2.Further,the annual effective dose commitments
demonstrate compliance with R313-15-10l(4)(10 CFR 20.1101(d»limit of 10 mrem/yr
to the individual member of the public likely to receive the highest total effective dose
equivalent.
10.4 Proposed Radiological Monitoring to Accommodate Cell 4b Operations
As an element of evaluating potential off-site doses related to the construction and
operation of Cell 4b,Denison commissioned a review of its environmental monitoring
programs in order to determine what,if any,additional monitoring would be needed to
accommodate the operation of Cell 4b.The review was conducted by SENES
Consultants,Ltd who concluded that the current environmental monitoring regime was
sufficient and that added monitoring was not warranted due to the operation of Cell 4b.
The results of the SENES review are attached here as Appendix C to this report.
11.0 Alternatives
The action under consideration is the construction of an already contemplated tailings
Cell (Cell 4b)in order accomodate continued operation of the Mill.The alternatives
available to the Executive Secretary are to:
a)Amend the License to include the construction of Cell 4b with its existing
terms and conditions;
b)Amend the License to include the construction ofCell 4b with such additional
conditions as are considered necessary or appropriate to protect public health,
safety and the environment;or
c)Deny the addition ofCe1l4b construction into the License.
As demonstrated in this ER,the environmental impacts associated with construction and
operation of Cell 4b do not warrant either limiting the Mill's future operations or denying
the Cell 4b construction approval request.As there are no significant public health,
safety or environmental impacts associated with the construction of Cell 4b,Denison
30
asserts that alternatives with equal or greater impacts need not be evaluated,and
alternative a)is the appropriate alternative for selection.
11.1 Issuance ofAmendment for Cell 4a
The Mill is one of only two operating uranium mills in the Unites States and the only
uranium mill on the western slope of the Rocky Mountains.As a result,the Mill is the
only cUlTently available opportunity for production of uranium from conventionally
mined ore in San Juan County and in the four comers area ofthe United States.The Mill
therefore provides a benefit to the regional community and to the uranium industry as a
whole in the United States.The construction of Cell 4b would allow the Mill to continue
to provide these benefits for many more years and as contemplated in the original
licensing effort.
As was demonstrated in Section 3 of the ER accompanying the 2007 License Renewal
Application,the Mill's equipment,facilities and procedures are adequate to minimize
impacts to public health,safety and the environment.More importantly,UDEQ has
already approved the construction of Cell 4a which is identical to Cell 4b with regard to
its robust and state-of-the-art protective design features.Also,the Mill has operated
since its inception in compliance with all applicable regulatory standards and ALARA
goals and is capable of continuing to operate in compliance with such standards and
goals.
In addition to the License,the Mill has been issued a Groundwater Discharge Permit,
which provides additional protection for public health and the environment,including a
rigorous groundwater monitoring program to monitor and assess the performance of
tailings cells associated with the facility.The Mill has demonstrated that it is capable of
continuing to operate in a manner that satisfies all regulatory standards and ALARA
goals under the existing terms and conditions ofthe License and GWDP,this amendment
application has assessed and proposed additional monitoring necessary to accommodate
newly constructed Cell 4b.Based upon these factors and considerations Denison asserts
that there is no need to add any additional conditions to the License in order to protect
public health,safety or the environment as a result ofCell 4b construction.
11.2 No Action Alternative
A "no action"alternative would result in the amendment request being denied and the
immediately available processing oppOliunities for mined uranium ore being lost in the
short term,severely impacting independent uranium miners in the area and lessening the
United States'capability to respond to the need for uranium for nuclear power
generation.
Denying the request for construction of Cell 4b severely constrain the utilization of the
Mill in the near term and eliminate its ability to operate over the longer term during a
time when commodity prices for uranium are favorable,and the demand for uranium
milling capacity is unprecedented.Permitting the Mill to continue processing
31
conventionally mined ore for the recovery ofuranium and the construction ofCell 4b will
provide the opportunity for regular employment in an economically depressed area ofthe
United States.A large percentage of the workers at the Mill are Native American,and
this employment opportunity has significant direct impact in the local Native American
community.In addition to the direct hiring of employees at the Mill,local miners and
other western United States mining companies require access to an operating uranium
mill.The inability of these mining entities to gain access to local milling services will
prevent the mining industry from responding to the current uranium supply shortage.
Thus,secondary local economies will not enjoy the benefit of renewed mining income,
and national demand for uranium will continue to be reliant primarily on foreign supplies
of uranium for nuclear fuel.In order to respond to the current uranium market,
conventional mining companies will be forced to license and construct new uranium
milling facilities to engage in conventional ore processing,directly in opposition to the
objective of non-proliferation of new uranium mill tailings disposal facilities embodied
by 10 CFR Part 40 Appendix A,Criterion 2.
As has been demonstrated by the forgoing assessments,the impacts associated with the
construction and operation of Cell 4b are well within the realm of impacts anticipated in
the FES,the 1985 EA and the 1997 EA,and UDEQ's approval of Cell 4b construction
will satisfy applicable criteria in R313-22-33 and R313-24.As a result,Denison asserts
that the Executive Secretary should have no basis for denying the proposed action.
11.3 Alternatives Considered But Eliminated
a)Consideration ofAlternative Sites
The Mill is already sited and in existence and has been operating for over 25 years.It is
not feasible to consider moving the Mill to an alternative site or to construct additional
tailing cells at a different location.Even ifthat were possible,it has been demonstrated
in Section 3 of the February,2007 ER accompanying the License Renewal Application
that the Mill is sited in a good hydrogeologic setting and is otherwise well sited for its
operations,including tailings cells contemplated at the time of the Mill's original
licensure.This is evident £i'om the fact that the Mill has operated since its inception in
compliance with applicable regulatory standards and ALARA goals.
If the construction of Cell 4b is not approved as an element of continued milling
operations,there can be no assurance that,as an alternative,an equally well-suited site
for milling and tailings cell contruction,that complies with the applicable siting
requirements of 10 CFR Part 40 Appendix A,can be identified and obtained.Even if a
suitable alternative site were to be identified and obtained,licensing and construction of a
new mill and tailings cells could not be accomplished in a time frame that would ensure
production could commence in a period of suitable market conditions.Furthermore,as
the existing Mill tailings would have to be decommissioned in place,creation of a new
mill site would result in unnecessary proliferation of mill tailings disposal facilities in
contravention of 10 CFR Part 40 Appendix A,Criterion 2.
32
b)Consideration ofAlternative Engineering Methods
As will be demonstrated in Section 3,the existing Mill facilities,equipment,procedures
and training of personnel have resulted in the Mill operating since inception in
compliance with all applicable regulatory standards and ALARA goals.Current
modeling demonstrates that the Mill is capable ofcontinuing to operate under the existing
terms and conditions of the License in a manner that will continue to comply with such
standards and goals.Furthermore,the Mill's GWDP institutes additional protections and
engineering controls,including the requirement that any new construction oftailings cells
must meet current best available technology standards.Therefore,there is no need to
consider alternative engineering methods.The existing equipment and facilities,together
with the existing terms and conditions of the License and the GWDP are sufficient to
ensure that all applicable requirements will continue to be satisfied.
11.4 Cumulative Effects
There are no past,present,or reasonably foreseeable future actions which could result in
cumulative impacts that have not been contemplated and previously approved under the
existing Mill License and the design ofCell 4b.
As stated throughout this License Amendment request,the Cell 4b construction will
result in no activity with potential,significant,incremental impacts to public health,
safety or the environment over and above the actions contemplated in the FES,the 1985
EA and the 1997 EA.The activities contemplated with regard to ore processing and
disposal of tailings remain unchanged from those previously authorized under the
License.
11.5 Comparison ofthe Predicted Environmental Impacts
There have been no observed significant impacts which were not previously quantified
and addressed to public health,safety or the environment resulting from the proposed
construction of Cell 4b.As there will be no significant changes in Mill operations if the
License is amended to accommodate construction of Cell 4b,possible impacts to public
health,safety or the environment will not exceed those predicted in the original License
application and periodic renewals.
11.6 Updates &Changes to Factors That May Cause Reconsideration of
Alternatives
As discussed in Section 12 below,Costs and Benefits,there have been no changes to
factors that may cause reconsideration of alternatives.There have been no significant
changes in the costs associated with operation of the Mill (including its impoundments),
and the benefits associated with continued operation and construction of already
contemplated tailing cells have become more evident over time as the number ofuranium
mills has dwindled and the demand for uranium milling service capacity from local
miners and the industry as a whole has increased in recent years.FurthelIDore,no new
33
alternatives to the services provided by the Mill and its impoundments have been
identified since the last License renewal in 1997.
12.0 Cost and Benefits
Appendix A to NUREG 1569 requires that the applicant for a license renewal describe
any updates and changes to the economic costs and benefits for the facility since the last
application.
There have been no significant changes to the costs associated with the Mill since the last
License renewal in 1997.While there will a change to the currently disturbed area as a
result of the Cell 4b construction,this additional Cell was contemplated,described and
assessed,as a critical component ofthe initial 1978 NRC-FEIS and attendant licensing of
the facility.As indicated in Section 3 of February,2007 ER accompanying the renewal
application,the Mill has operated in accordance with applicable regulatory standards and
ALARA goals since its inception,and updated MILDOS AREA modeling indicates that
the Mill is capable ofcontinuing to operate well within those standards and goals.There
have been no significant demographic changes that have impacted the ability of the Mill
to operate in a manner that will result in no significant impacts to public health,safety or
the environment.It is expected that continued Mill operations will continue to draw
primarily upon the existing work force in the area with little impact on social services.
The Mill is one of only two operating uranium mills in the United States and is one ofthe
largest private employers in San Juan County.The benefits of the Mill will continue to
be the provision ofwell-paying jobs to workers in San Juan County and the support ofthe
tax base in that County.Moreover,as the only operating uranium mill on the western
slope ofthe Rocky Mountains,the Mill is relied upon by the large number of independent
uranium miners in San Juan County and the Colorado Plateau as the only feasible
uranium mill for their uranium ores.With the recent gap between the supply and demand
for uranium and the increases in the price ofuranium,the need for continued licensing of
the Mill is crucial for such miners and for the uranium industry in the United States as a
whole.
In sum,the costs associated with the operation ofthe Mill have not changed significantly,
but the benefits have become more evident over time as the number ofuranium mills has
dwindled and the demand for uranium milling services from local miners and the industry
as a whole has increased.
13.0 Mitigation of Impacts
NUREG 1569 requires that the ER provide the "results ofeffectiveness ofany mitigation
proposed and implemented in the origina11icense".In the case ofthe White Mesa Mill,
there have not been any mitigations proposed or implemented under the License.
34
14.0 Long Term Impacts
The long term impacts,including decommissioning,decontamination,and reclamation
impacts associated with activities conducted pursuant to the License have been
considered in detail in the FES,the Mill's Reclamation Plan,and the 2000 EA prepared
by the NRC in connection with the Reclamation Plan.
The Mill's Reclamation Plan and financial surety arrangements,as well as the provisions
in the Mill's GWDP that relate to final reclamation ofthe site are described in detail in
Section 8 ofthe February,2007 License Renewal Application,and are incorporated here
by reference.The construction ofCell 4b will not result in any changes to operations at
the Mill that would impact decommissioning,decontamination or reclamation aspect
associated with Mill activities,or the previous analyses ofsuch aspects.The grading
contours and other reclamation features related to closure ofCell 4b at site closure are
shown in Figure 12.All design features for Cell 4b are included in the Cell 4b Design
Report prepared by Geosyntec Consultants which was transmitted to UDEQ in January of
2008.
35
Appendix A
SITE HYDROGEOLOGY
ESTIMATION OF GROUNDWATER TRAVEL TIMES
AND RECOMMENDED ADDITIONAL MONITORING WELLS
FOR PROPOSED TAILINGS CELL 4B
WHITE MESA URANIUM MILL SITE
NEAR BLANDING,UTAH
Prepared for:
DENISON MINES (USA)CORP
Independence Plaza,Suite 950
1050 1i h Street
Denver,Colorado 80265
[phone]
Prepared by:
HYDRO GEO CHEM,INC.
51 West Wetmore,Suite 101
Tucson,Arizona 85705-1678
[phone]
January 8,2008
TABLE OF CONTENTS
1.INTRODUCTION 1
2.SITE HyDROGEOLOGy 3
2.1 Geologic Setting 3
2.2 Hydrogeologic Setting 4
2.3 Perched Zone Hydrogeology 5
2.3.1 Lithologic and Hydraulic Properties 6
2.3.1.1 Dakota 7
2.3.1.2 Burro Canyon 7
2.3.2 Perched Groundwater Flow 9
3.PERCHED ZONE HYDROGEOLOGY BENEATH AND DOWNGRADIENT
OF THE TAILINGS CELLS 11
3.1 Saturated Thickness 11
3.2 Perched Water Flow 12
3.3 Permeability 13
4.EVALUATION OF POTENTIAL FLOW PATHS AND TRAVEL TIMES
FOR HYPOTHETICAL SEEPAGE ORIGINATING FROM CELL #3 15
4.1 Estimated Travel Time from the Base ofCell #3 and Proposed Cell 4B
to the Perched Zone 15
4.2 Estimated Travel Times from Tailings Cell #3 and Proposed Cell4B
to Ruin Spring 16
4.3 Estimated Total Travel Time from the Base ofTailings Cell #3
and Proposed Cell4B to Ruin Spring 17
5.RECOMMENDED ADDITIONAL PERCHED ZONE MONITORING WELLS
DOWNGRADIENT OF PROPOSED CELL 4B 21
6.REFERENCES 23
7.LIMITATIONS STATEMENT 25
TABLES
1 Peel Hydraulic Test Results
2 Results ofJuly 2002 and June 2005 Hydraulic Tests
Site Hydrogeology OWTravel Times Proposed Wells Ce1l4B
H:\718000\ce1l4blhydrce1l4b.doc
January 8,2008
TABLE OF CONTENTS (Continued)
FIGURES
1 Site Plan and Perched Well Locations
2 Kriged Brushy Basin Contact Elevations
3 Perched Water Levels,August 1990
4 Perched Water Levels,August 1994
5 Perched Water Levels,September 2002
6 Kriged 3rd Quarter,2007 Water Levels
7 Portion of USGS Black Mesa 7.5'Sheet Showing Approximate Location ofTailing Cells
in Relation to Nearby Canyons and Ruin Spring
8 Depth to Water,3rd Quarter 2007
9 Approximate Saturation Thickness,3rd Quarter 2007
10 Site Plan Showing Existing and Proposed Perched Well Locations
Site Hydrogeology GW Travel Times Proposed Wells Cell 4B
H:\718000\ce1l4b\hydrce1l4b.doc
Januaty 8,2008 11
1.INTRODUCTION
This report provides a brief description of the hydrogeology of the White Mesa Uranium
Mill site (the "Mill"or the "site"),located south of Blanding,Utah,and focuses on the
occurrence and flow of groundwater within the relatively shallow perched groundwater zone at
the site.Based on available existing hydrogeologic information from the site,estimates of
hydraulic gradients and intergranular rates of groundwater movement (interstitial or pore
velocities)are provided.These estimates are used to calculate average travel times for a
hypothetical conservative solute (assuming no dispersion)from existing tailings cell #3 and
proposed cell 4B at the site to a downgradient discharge point.Recommendations for additional
perched zone monitoring wells downgradient ofproposed cell4B are also provided.Figure 1 is a
site plan showing the locations ofperched monitoring wells and proposed cell4B.
Tailings cell #3 has been in service for many years and a large quantity of groundwater
monitoring and hydraulic test data exists for perched monitoring wells completed around the
perimeter of the cell.Data from the vicinity of the cell are used in conjunction with data
downgradient of the cell to calculate perched zone hydraulic properties and groundwater
gradients between cell #3 and the discharge point.Cell 4B is proposed to be installed at the
downgradient edge of cell #3.The data from the immediate vicinity and downgradient ofcell #3
used to compute rates of movement and travel times for a hypothetical conservative solute will
likewise be used to calculate travel times for the hypothetical solute from proposed ce1l4B to the
discharge point.
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2.SITE HYDROGEOLOGY
Titan,1994 provides a detailed description of site hydrogeology based on infonnation
available at that time.A brief summary of site hydrogeology that is based primarily on Titan,
1994,but includes the results ofmore recent site investigations,is provided below.
2.1 Geologic Setting
The White Mesa Uranium Mill site is located within the Blanding Basin ofthe Colorado
Plateau physiographic province.Typical of large portions of the Colorado Plateau province,the
rocks underlying the site are relatively undefonned.The average elevation of the site is
approximately 5,600 feet above mean sea level (amsl).
The site is underlain by unconsolidated alluvium and indurated sedimentmy rocks
consisting primarily of sandstone and shale.The indurated rocks are relatively flat lying with
dips generally less than 3°.The alluvial materials consist mostly ofaeolian silts and fine-grained
aeolian sands with a thickness varying from a few feet to as much as 25 to 30 feet across the site.
The alluvium is underlain by the Dakota Sandstone and Burro Canyon Fonnation,which are
sandstones having a total thickness ranging from approximately 100 to 140 feet.Beneath the
Burro Canyon Fonnation lies the Morrison Fonnation,consisting,in descending order,of the
Brushy Basin Member,the Westwater Canyon Member,the Recapture Member,and the Salt
Wash Member.The Brushy Basin and Recapture Members of the Morrison Fonnation,
classified as shales,are very fine-grained and have a very low permeability.The Brushy Basin
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Member is primarily composed of bentonitic mudstones,siltstones,and claystones.The
Westwater Canyon and Salt Wash Members also have a low average vertical permeability due to
the presence of interbedded shales.
Beneath the Morrison Formation lie the Summerville Formation,an argillaceous
sandstone with interbedded shales,and the Entrada Sandstone.Beneath the Entrada lies the
Navajo Sandstone.The Navajo and Entrada Sandstones constitute the primary aquifer in the
area of the site.The Entrada and Navajo Sandstones are separated from the Burro Canyon
Formation by approximately 1,000 to 1,100 feet of materials having a low average vertical
permeability.Groundwater within this system is under artesian pressure in the vicinity of the
site,is ofgenerally good quality,and is used as a secondary source ofwater at the site.
2.2 Hydrogeologic Setting
The site is located within a region that has a dry to arid continental climate,with average
annual precipitation of less than 11.8 inches,and average annual evapotranspiration of
approximately 61.5 inches.Recharge to aquifers occurs primarily along the mountain fronts (for
example,the Henry,Abajo,and La Sal Mountains),and along the flanks of folds such as Comb
Ridge Monocline.
Although the water quality and productivity of the Navajo/Entrada aquifer are generally
good,the depth of the aquifer (approximately 1,200 feet below land surface [blsD makes access
difficult.The Navajo/Entrada aquifer is capable of yielding significant quantities of water to
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wells (hundreds ofgallons per minute [gpm]).Water in wells completed across these units at the
site rises approximately 800 feet above the base ofthe overlying Summerville Formation.
Perched groundwater in the Dakota Sandstone and Burro Canyon Formation is used on a
limited basis to the north (upgradient)of the site because it is more easily accessible.Water
quality ofthe Dakota Sandstone and Burro Canyon Formation is generally poor due to high total
dissolved solids (TDS)and is used primarily for stock watering and irrigation.The saturated
thickness of the perched water zone generally increases to the north of the site,increasing the
yield ofthe perched zone to wells installed north ofthe site.
2.3 Perched Zone Hydrogeology
Perched groundwater beneath the site occurs primarily within the Burro Canyon
Formation.Perched groundwater at the site has a generally low quality due to high total
dissolved solids (TDS)in the range ofapproximately 1,200 to 5,000 milligrams per liter (mg/L),
and is used primarily for stock watering and irrigation in the areas upgradient (north)ofthe site.
Perched water is supported within the Burro Canyon Formation by the underlying,fine-grained
Brushy Basin Member.Figure 2 is a contour map showing the approximate elevation of the
contact of the Burro Canyon Formation with the Brushy Basin Member,which essentially forms
the base of the perched water zone at the site.Contact elevations are based on perched
monitoring well drilling and geophysical logs and surveyed land surface elevations.As
indicated,the contact generally dips to the south/southwest beneath the site.
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Groundwater within the perched zone generally flows south to southwest beneath the site.
Beneath the tailings cells,perched water flow is generally southwest to south-southwest.
2.3.1 Lithologic and Hydraulic Properties
Although the Dakota Sandstone and Burro Canyon Formations are often described as a
single unit due to their similarity,previous investigators at the site have distinguished between
them.The Dakota Sandstone is a relatively-hard to hard,generally fine-to-medium grained
sandstone cemented by kaolinite clays.The Dakota Sandstone locally contains discontinuous
interbeds of siltstone,shale,and conglomeratic materials.Porosity is primarily intergranular.
The underlying Burro Canyon Formation hosts most ofthe perched groundwater at the site.The
Burro Canyon Formation is similar to the Dakota Sandstone but is generally more poorly sorted,
contains more conglomeratic materials,and becomes argillaceous near its contact with the
underlying Brushy Basin Member.The permeability ofthe Dakota Sandstone and Burro Canyon
Formation at the site is generally low.
No significant joints or fractures within the Dakota Sandstone or Burro Canyon
Formation have been documented in any wells or borings installed across the site (Knight
Piesold,1998).Any fractures observed in cores collected from site borings are typically
cemented,showing no open space.
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2.3.1.1 Dakota
Based on samples collected during installation of wells MW-16 (no longer in service)and
MW-17,located immediately downgradient of the tailings cells at the site,porosities of the
Dakota Sandstone range from 13.4 to 26 percent,averaging 20 percent,and water saturations
range from 3.7 to 27.2 percent,averaging 13.5 percent.The average volumetric water content is
approximately 3 percent.The permeability of the Dakota Sandstone based on packer tests in
borings installed at the site ranges from 2.71 x 10-6 centimeters per second (cm/s)to 9.12 x 10-4
cm/s,with a geometric average of3.89 x 10-5 cm/s.
2.3.1.2 Burro Canyon
The average porosity of the Burro Canyon Formation is similar to that of the Dakota
Sandstone.Based on samples collected from the Burro Canyon Formation at MW-16,located
immediately downgradient of the tailings cells at the site (and no longer in service),porosity
ranges from 2 to 29.1 percent,averaging 18.3 percent,and water saturations of unsaturated
materials range from 0.6 to 77.2 percent,averaging 23.4 percent.Titan,1994,reported that the
hydraulic conductivity ofthe Burro Canyon Formation ranges from 1.9 x 10-7 to 1.6 x 10 -3 cm/s,
with a geometIic mean of 1.1 x 10-5 cm/s,based on the results of 12 pumping/recovery tests
performed in monitoring wells and 30 packer tests performed in borings prior to that time.
Hydraulic testing of wells MW-Ol,MW-03, MW-05,MW-17,MW-18, MW-19,MW-
20,and MW-22 during the week of July 8,2002,and newly installed wells MW-23,MW-25,
MW-27,MW-28, MW-29, MW-30, MW-31,MW-32,TW4-20,TW4-21,and TW4-22 during
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June,2005,yielded average perched zone permeabilities ranging from approximately 2 x 10-7
cm/s to 5 x 10-4 cm/s,similar to the range reported by previous investigators at the site (Hydro
Geo Chern,Inc [HGC],2002;HGC,2005).Downgradient (south to southwest)of the tailings
cells,average perched zone permeabilities based on tests at MW-3,MW-5,MW-17, MW-20,
MW-22,and MW-25 ranged from approximately 4 x 10-7 to 1 X 10-4 cm/s Permeability
estimates from these tests were based on pumping/recovery and slug tests analyzed using several
different methodologies.
A number of temporary (TW4-series)perched zone monitoring wells have been installed
at the site to investigate elevated concentrations of chloroform initially discovered at well MW-4
in 1999.Some of the conglomeratic zones encountered within the perched zone during
installation of these wells are believed to be partly continuous or at least associated with a
relatively continuous zone of higher permeability (International Uranium [USA]Corporation
[IUSA]and HGC,2001).The higher permeability zone defined by these wells is generally
located east to northeast of the tailings cells at the site,and is hydraulically cross-gradient to
upgradient of the tailings cells with respect to perched groundwater flow.Relatively high
permeabilities measured at MW-11,located on the southeastern margin of the downgradient
edge of tailings cell #3,and at MW-14,located on the downgradient edge of tailings cell #4,of
1.4 X 10-3 cm/s and 7.5 x 10-4 cm/s,respectively (UMETCO,1993),may indicate that this zone
extends beneath the southeastern margin ofthe cells.This zone ofhigher permeability within the
perched water zone does not appear to exist downgradient (south-southwest)of the tailings cells,
however.At depths beneath the perched water table,the zone is not evident in lithologic logs of
the southernmost temporary wells TW4-4 and TW4-6 (located east [cross-gradient]of cell #3),
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nor is it evident in wells MW-3,MW-5,MW-12,MW-15,MW-16,MW-17,MW-20,MW-21,
or MW-22,located south to southwest (downgradient)of the tailings cells,based on the
lithologic logs or hydraulic testing ofthe wells.
Because of the generally low permeability of the perched zone beneath the site,well
yields are typically low (less than 0.5 gpm),although sustainable yields of as much as about
4 gpm may be possible in wells intercepting larger saturated thicknesses and higher permeability
zones in the northeast portion of the site.Sufficient productivity can,in general,only be
obtained in areas where the saturated thickness is greater,which is the primary reason that the
perched zone has been used on a limited basis as a water supply to the north (upgradient)of the
site.
2.3.2 Perched Groundwater Flow
Perched groundwater flow at the site has historically been to the south/southwest.
Figures 3 through 6 are perched groundwater elevation contour maps for the years 1990, 1994,
2002,and 2007,respectively.The 1990,1994,and 2002 maps were hand contoured because of
sparse data.As groundwater elevations indicate,the perched groundwater gradient changes from
generally southwesterly in the western portion of the site,to generally southerly in the eastern
portion of the site.The most significant changes between the 2002 and 2007 water levels result
from pumping of wells MW-4,TW4-19,TW4-20,and MW-26.These wells are pumped to
reduce chloroform mass in the perched zone east and northeast of the tailings cells.
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In general,perched groundwater elevations have not changed significantly at most of the
site monitoring wells since installation,except in the vicinity of the wildlife ponds and the
pumping wells.For example,relatively large increases in water levels occurred between 1994
and 2002 at MW-4 and MW-19,located in the east and northeast portions of the site,as shown
by comparing Figures 4 and 5.These water level increases in the northeastern and eastern
portions of the site are likely the result of seepage from wildlife ponds located near the
piezometers shown in Figure 5,which were installed in 2001 for the purpose of investigating
these changes.The increase in water levels in the northeastern portion of the site has resulted in
a local steepening of groundwater gradients over portions of the site.Conversely,pumping of
wells MW-4,TW4-l9,TW4-20,and MW-26 has depressed the perched water table locally and
reduced average hydraulic gradients to the south and southwest ofthese wells.
Perched water discharges in springs and seeps along Westwater Creek Canyon and
Cottonwood Canyon to the west-southwest of the site,and along Corral Canyon to the east ofthe
site,where the Burro Canyon Formation outcrops.The discharge point located most directly
downgradient of the tailings cells is Ruin Spring.This feature is located approximately 10,000
feet south-southwest of tailings cell #3 and is depicted on the USGS 7.5-minute quad sheet for
Black Mesa (Figure 7).
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3.PERCHED ZONE HYDROGEOLOGY BENEATH AND DOWNGRADIENT OF
THE TAILINGS CELLS
Perched water as of the 3rd Quarter,2007 was encountered at depths ofapproximately 57
to 115 feet bls in the vicinity of the tailings cells at the site (Figure 8).Beneath tailings cell #3,
depths to water ranged from approximately 77 feet below top of casing (btoc)in the eastem
portion of the cell (at MW-25),to approximately 114 feet btoc at the southwest margin ofthe cell
(at MW-23).Assuming an average depth of the base of tailings cell #3 of 25 feet below grade,
this corresponds to perched water depths of approximately 52 to 89 feet below the base of the
cell,or an average depth of approximately 70 feet beneath the base of the cell.A similar
assumption can be made for proposed cell4B.
3.1 Saturated Thickness
The saturated thickness of the perched zone as of the 3rd Quarter,2007 ranges from
approximately 93 feet in the northeast portion of the site to less than 5 feet in the southwest
portion of the site (Figure 9).Beneath tailings cell #3,the saturated thickness varies from
approximately 49 feet in the eastemmost comer ofthe cell to approximately 7 feet in the westem
portion of the cell.South-southwest of the tailings cells,the saturated thickness ranges from less
than 1 foot at MW-21 to approximately 26 feet at MW-17.The average saturated thickness
south-southwest ofthe tailings cells,based on measurements at MW-3, MW-5,MW-12,MW-14,
MW-15,MW17,and MW-20,is approximately 14 feet.The average saturated thickness based
on measurements at MW-5,MW-15,MW-3,and MW-20,which lay close to a line between the
center oftailings cell #3 and Ruin Spring,is approximately 12 feet.By projecting conditions at
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these wells,the average saturated thickness IS estimated to be approximately 10 to 15 feet
between MW-20 and Ruin Spring.
3.2 Perched Water Flow
Perched groundwater flow beneath the tailings cells has historically been southwest,with
the gradient steepening in recent years (since about 1994)and becoming more westerly as
perched water levels in the northeastern portion of the site have risen.Perched water flowing
beneath the tailings cells eventually discharges in springs and seeps located in Westwater
Canyon,to the south-southwest of the cells.The primary discharge point for perched water
flowing beneath the tailings cells is believed to be Ruin Spring,located approximately 10,000
feet south-southwest ofthe cells.
Perched zone hydraulic gradients currently range from a maximum ofapproximately 0.05
feet per foot (ftlft)east of tailings cell #2 to approximately 0.01 ftlft downgradient of cell #3,
between cell #3 and MW-20.The average hydraulic gradient between the downgradient edge of
tailings cell #3 and Ruin Spring can be approximated assuming the following:
1)The elevation of Ruin Spring,based on the USGS topographic map for Black Mesa,
is approximately 5,390 feet amsl.
2)The distance between the downgradient edge of tailings cell #3 and Ruin Spring is
approximately 10,000 feet.
3)The average groundwater elevation at the downgradient edge of tailings cell #3 is
approximately 5,510 feet amsl.
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Using these assumptions,the average perched zone hydraulic gradient between tailings cell #3
and Ruin Spring is approximately:
5510 -5390 =0.012fl /fl
10,000
A hypothetical worst case average perched zone hydraulic gradient can also be estimated
assuming the perched water elevation to be coincident with the base of tailings cell #3.The
elevation of the base of tailings cell #3,which is also the approximate pre-existing land surface
elevation near the center of the cell,is approximately 5,580 feet amsl.Under these conditions,
for an unconfined perched zone,the maximum possible average perched zone hydraulic gradient
between tailings cell #3 and Ruin Spring would be approximately:
5580 -5390 =0.019fl /fl
10,000
Although the downgradient edge of proposed cell 4B is closer to Ruin Spring (approximately
9,000 feet from Ruin Spring rather than about 10,000 feet),the above hydraulic gradient
calculations can also be applied to ce1l4B.
3.3 Permeability
The average permeability of the perched zone downgradient of tailings cell #3 can be
approximated based on the pumping/recovery test and slug test data obtained from perched zone
wells located along the downgradient edge of and south of cell #3.Peel conducted hydraulic
tests at perched zone wells MW-ll,MW-12, MW-14,and MW-15 in 1992 (UMETCO,1993).
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Results of these tests are provided in Table 1.HGC conducted slug tests at perched zone wells
MW-3, MW-5,MW-17, MW-20,and MW-22 in July 2002 (HGC,2002),and MW-25 in June,
2005 (HGC,2005).
The HGC slug test results were analyzed using various solution methods including KGS
(Hyder,1994),and Bouwer-Rice (Bouwer and Rice,1976).Each method yielded slightly
different results as shown in Table 2,which is based on Table 1 of HGC,2002,and Table 1 of
HGC,2005.A range of average permeabilities for the portion of the site south of the tailings
cells can be obtained by taking the geometric mean of the Peel test results and the results
obtained by the various solution methods used to analyze the HGC data.Averaging the Peel test
results for wells MW-ll,MW-12, MW-14,and MW-15 with the HGC KGS results for wells
MW-3, MW-5,MW-17,MW-20,MW-22,and MW-25 yields a geometric average of 2.3 x 10-5
cm/s,and similarly averaging the Peel test results with the HGC Bouwer-Rice results yields a
geometric average of 4.3 x 10-5 cm/s,as shown in Table 2.The "early time"results at MW-5
using the Bouwer-Rice solution (from Table 1 of HGC,2002)were used in the computations to
yield a conservatively high estimate ofpermeability.
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4.EVALUATION OF POTENTIAL FLOW PATHS AND TRAVEL TIMES FOR
HYPOTHETICAL SEEPAGE ORIGINATING FROM CELL #3
Although more than 25 years ofgroundwater monitoring at the site has shown no impact
to perched water from the tailings cells,an evaluation of hypothetical transport of a conservative
solute in seepage from existing cell #3 and proposed cell 4B is presented assuming a flow path
from the base ofthe existing and proposed cells to the perched water,and thence to Ruin Spring.
Average travel times for a conservative constituent moving from the base of tailings cell #3 and
proposed cell 4B to the perched water,and then moving with the perched water to Ruin Spring,
are computed assuming no dispersion.
The porosities and water saturations used in the calculations were based on measurements
reported in Titan,1994,for samples collected from the Dakota Sandstone during drilling ofMW-
16 and MW-17,and from the Burro Canyon Formation during drilling ofMW-16.
4.1 Estimated Travel Time from the Base of Cell #3 and Proposed Ce1l4B to the Perched
Zone
Knight-Piesold estimated a maximum volumetric seepage rate for tailings cell #3 based
on cell construction and liner characteristics,of approximately 80 cubic feet per day (ft/day)or
0.42 gpm over the entire cell (Knight-Piesold,1998).Most of this seepage was estimated to be
via diffusion through the liner.This rate was estimated to decrease over time as the cell
desaturates once the final cover is emplaced.Assuming a cell footprint of3.38 x 106 ft 2,this rate
is equivalent to 2.37 x 10-5 ft/day or 0.0086 feet per year (ft/yr).
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The average rate of downward movement of a conservative solute dissolved in the
seepage,assummg 1)no dispersion,2)an average water saturation of 0.20,3)an average
porosity of 0.18,and assuming that this rate of seepage would not significantly raise the average
saturation of the underlying materials,can be approximated as:
0.0086ft I yr =0.24ftI r
(.20)(.18)y
The average time to travel 70 feet to the perched water zone would then be approximately 290
years.This is a conservative estimate because the average water saturations would be likely to
increase,thereby reducing the downward rate oftravel,and increasing the travel time.
Assuming a similar travel time from the base of proposed cell 4B to the perched water
would be even more conservative because the improved liner system to be used for that cell
would result in less seepage than from cell #3.However,for purposes of calculation,potential
seepage rates and downward rates of movement for a hypothetical conservative solute will be
assumed to be the same for cell4B as those calculated for cell #3.
4.2 Estimated Travel Times from Tailings Cell #3 and Proposed Cell 4B to Ruin Spring
Under current conditions,the average hydraulic gradient between the downgradient edge
oftailings cell #3 to Ruin Spring is estimated to be 0.012,as discussed in Section 3.2.Assuming
the following:
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Average porosity =0.18
Average hydraulic gradient =0.012
Flow path length =10,000 feet
Average permeability range =2.3 x 10-5 to 4.3 X 10-5 cm/s
(0.064 ft/day to 0.120 ft/day)
the average rate of intergranular movement of perched groundwater (interstitial or pore velocity)
can be approximated to range from 0.0043 ft/day to 0.0080 ft/day (or 1.6 ft/yr to 2.9 ftlyr).The
estimated average travel time for a conservative solute,assuming no dispersion,from tailings
cell #3 to Ruin Spring would then be approximately 6,250 to 3,450 years over this range of
permeabilities.Under conditions of the maximum possible average perched groundwater
gradient of 0.019 ftlft,as estimated in Section 3.2,and assuming the same permeabilities,
porosity,and path length as above,the estimated average travel times would range from
approximately 4,055 to 2,160 years.
For proposed cell 4B,which is about 9,000 feet from Ruin Spring,the estimated travel
times would be approximately 5,625 to 3,100 years using the gradient of 0.012,and
approximately 3,650 to 1,950 years using the gradient of 0.019.
4.3 Estimated Total Travel Time from the Base ofTailings Cell #3 and Proposed Cell 4B
to Ruin Spring
The total average travel time for a conservative solute from the base oftailings cell #3 or
proposed cell 4B to Ruin Spring under current conditions would be the sum of 1)the travel time
from the base of either cell to the perched water table,and 2)the time to travel within the
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perched zone to Ruin Spring.Based on the estimates provided in Sections 4.1 and 4.2,the total
average travel time of a conservative solute (assuming no dispersion)over the range of average
permeability estimates would be between 6,540 and 3,740 years for cell #3,and between 5,915
and 3,390 years for proposed cell 4B,assuming an average hydraulic gradient of 0.012 ft/ft.As
discussed in Section 4.1,because the rate of movement ofa conservative solute from the base of
cell 4B would likely be slower than for cell #3 because seepage rates would lower,the total
travel time would likely be higher than estimated above.
Conditions may hypothetically develop under which travel times may be reduced,such as
an increase in average perched zone groundwater gradients between tailings cell #3 or cell 4B
and Ruin Spring (as discussed in Section 3.2)or as a result ofreduced vadose zone travel times
due to development of a relatively large leak in either cell.Under hypothetical conditions in
which a relatively large leak were to develop,potentially reducing vadose zone travel times to
only a few years,the vadose zone travel time could be ignored,and the total average travel time
(assuming no dispersion)would range from approximately 6,250 to 3,450 years for cell #3,and
between 5,625 and 3,100 years for proposed cell 4B,assuming an average hydraulic gradient of
0.012 ftlft.Under hypothetical conditions in which the average perched zone hydraulic gradient
between either cell and Ruin Spring reached 0.019 ftlft,which also implies a negligible vadose
zone travel time,the total average travel time (assuming no dispersion)over the estimated range
in permeability would be between approximately 4,055 and 2,160 years for cell #3,and between
3,650 and 1,950 years for ce1l4B.
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Estimates based on hypothetical assumptions of a relatively large leak in tailings cell #3
or an average hydraulic gradient as high as 0.019 ftlft between either cell and Ruin Spring are
considered very conservative because they assume conditions that are unlikely ever to develop.
Furthermore the improved construction and leak detection system proposed for cell 4B would
make this hypothetical scenario even less likely for cell4B than for cell #3.
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5.RECOMMENDED ADDITIONAL PERCHED ZONE MONITORING WELLS
DOWNGRADIENT OF PROPOSED CELL 4B
The current perched groundwater monitoring well network for the tailings cells includes
wells that are upgradient,crossgradient,and downgradient of the cells as shown in Figure 10.
Most ofthe wells are located along the margins of the cells and many that are between the cells
function as both upgradient wells for the cell located immediately downgradient of the wells and
as downgradient wells for the cell located immediately upgradient of the wells.For example,
well MW-30 functions as a downgradient well for cell #2 and as an upgradient well for cell #3.
Wells MW-5,MW-12,and MW-23 that currently function as downgradient wells for cell #3
would also serve as upgradient wells for proposed cell 4B.The current arrangement of tailings
cell perched monitoring wells is conservative with respect to u.s.Environmental Protection
Agency (US EPA)Draft Technical Guidance (US EPA,1992)which generally recommends
downgradient wells only along the downgradient margin of the facility which in this case would
be the entire complex oftailings cells.
Once proposed cell 4B is installed,an additional well or wells would be needed at the
downgradient edge of the cell to be consistent with EPA Draft Guidance (US EPA,1992).As
shown in Figure 10,two additional wells are proposed,one at the southwest comer ofproposed
ce1l4B and one between the southwest comer well and existing well MW-15.These installations
would conservatively maintain the approximate existing spacing as defined by the proximity of
MW-14 to MW-15 along the downgradient edge of existing cell 4A.Existing wells MW-3,
MW-20,and MW-21 would continue to function as distal downgradient wells for the entire cell
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January 8,2008 21
complex.Once installed,sampling frequencies for the new wells will be based on testing of the
wells for perched zone hydraulic properties in the same fashion as for the existing wells.
Site Hydrogeology GW Travel Times Proposed Wells Cell 4B
H:\718000\ce1l4b\hydrce1l4b.doc
January 8,2008 22
6.REFERENCES
Bouwer,H.and R.C.Rice.1976.A slug test method for determining hydraulic conductivity of
unconfined aquifers with completely or partially penetrating wells.Water Resources
Research,Vo.12:3.Pp.423-428.
Hyder,Z.,II Butler,C.D.McElwee,and W.Liu.1994.Slug tests in partially penetrating
wells.Water Resources Research.Vol.30:11.Pp.2945-2957.
Hydro Geo Chem.2001.Update to report "Investigation of Elevated Chloroform
Concentrations in Perched Groundwater at the White Mesa Uranium Mill Near Blanding,
Utah".
Hydro Geo Chem.2002.Hydraulic Testing at the White Mesa Uranium Mill Near Blanding,
Utah During July,2002.Submitted to International Uranium (USA)Corporation,
Denver,Colorado.
Hydro Geo Chem.2005.Perched Monitoring Well Installation and Testing at the White Mesa
Uranium Mill,April Through June,2005.Submitted to International Uranium (USA)
Corporation,Denver,Colorado.
Knight-Piesold.1998.Evaluation of Potential for Tailings Cell Discharge -White Mesa Mill.
Attachment 5,Groundwater Information Report,White Mesa Uranium Mill,Blanding,
Utah.Submitted to UDEQ.
TITAN.1994.Hydrogeological Evaluation ofWhite Mesa Uranium Mill.Submitted to Energy
Fuels Nuclear.
UMETCO.1993.Groundwater Study.White Mesa Facilities.Blanding,Utah.Prepared by
UMETCO Minerals Corporation and Peel Environmental Services.
US EPA.1992.EPA RCRA Ground-Water Monitoring:Draft Technical Guidance,
November 1992.
Site Hydrogeology OW Travel Times Proposed Wells Cell 4B
H:\718000\ce1l4blhydrce1l4b.doc
January 8.2008 23
Site Hydrogeology GW Travel Times Proposed Wells Cell 4B
H:\718000\ceIl4b\hydrceIl4b.doc
January 8,2008 24
7.LIMITATIONS STATEMENT
The opinions and recommendations presented in this report are based upon the scope of
services and information obtained through the performance of the services,as agreed upon by
HOC and the party for whom this report was originally prepared.Results of any investigations,
tests,or findings presented in this report apply solely to conditions existing at the time HOC's
investigative work was performed and are inherently based on and limited to the available data
and the extent of the investigation activities.No representation,warranty,or guarantee,express
or implied,is intended or given.HOC makes no representation as to the accuracy or
completeness of any information provided by other parties not under contract to HOC to the
extent that HOC relied upon that information.This report is expressly for the sole and exclusive
use of the party for whom this report was originally prepared and for the particular purpose that
it was intended.Reuse of this report,or any portion thereof,for other than its intended purpose,
or ifmodified,or ifused by third parties,shall be at the sole risk ofthe user.
Site Hydrogeology GW Travel Times Proposed Wells Cell4B
H:\718000\celJ4b\hydrcelJ4b.doc
January 8,2008 25
Site Hydrogeology GW TravelTimes Proposed Wells Cell 48
H:\718000\ceIl4b\hydrceIl4b.doc
January 8,2008 26
TABLES
TABLE 1
Peel Hydraulic Test Results 1
Well Hydraulic Conductivity
(em/s)
MW-11 1.4 x 10-3
MW-12 2.2 x 10-5
MW-14 7.5x10-4
MW-15 1.9 x 10-:>
Notes:
1 From UMETCO,1993
H:1718000\ceIl4bITables.xls:Table 1 1/8/2008
TABLE 2
Results of July 2002 and June 2005 Hydraulic Tests 2
Well Permeability in centimeters per second
KGS Bouwer-Rice
MW-3 4.0 x 10-7 1.5 X 10-5
MW-5 3.5 x 10-6 2.4 x 10'5
MW-17 2.6 x 10-5 2.7 X 10-5
MW-20 --9.3 x 10-6
MW-22 1.0 x 10-6 7.9x10-6
MW-25 1.1 x 10-4 7.4 x 10-5
Geometric Average ofabove test results with Peel 3 test results for MW-11,
MW-12,MW-14,and MW-15.
2.3 X 10'5
Notes:
2 From HGC,2002;HGC,2005
3 From UMETCO,1993
H:\718000\ceIl4b\Tables.xls:Table 2
4.3 X 10-5
1/8/2008
FIGURES
PROPERTY
BOUNDARY
PIEZ·1.
MW-19•..
PIEZ·2.
PIEZ·3.
4-1l!bTw.._11 arw....13
TW..ai.
OTW4-'
OTW4.5
-26 TW4.1cf>TW4--0oQTW4.3 OTW4·12
*PIEZ·5.
MW·18•
28
MW·01•
CELL NO.2
CELL NO.
MW-17•
MW·02•
MW·2+
32
I
A
If
II
II~1...;::.-~.=-.:::!--
MW·OJ•T37S
1H:/718000/cell4b/welloc.srl
MW·22•II
//
////
//
//
//
//
//
//
//
SITE PLAN
AND PERCHED WELL LOCATIONS
WHITE MESA SITE
T38S
SJS
HYDRO
GEO
CHEM,INC.
f wildlife pond
3000
MW·20•
perchedmonitoring well
temporary perched monitoring well
perched piezometer
perched monitoring well
installedApril,2005
temporary perched monitoring
well installedApril,200S
newtemporaryperched monitoring well
installed May,2007 (locations approximate)
EXPLANATION
N
1
SCALE IN FEET
o
MW·20•..,.o
PIEZ·1•MW·31•rw4020-¢-
TW""~
I;,
II
II
1\~1:.~...:::::...=-,;:!.-
\\
\\
\\
MW·01"'31
28
[j'1
\
'\PIEZ·1
"-.:...2
PIEZ·2_5538
SCALE IN FEET
2H:/718000/ceIl4b/bbeI0705.srf
5420_
T37S 5460 _
_----5440_
SJS
KRIGED BRUSHY BASIN CONTACT ELEVATIONS
WHITE MESA SITE
4 #
~#===============p
~II
/M~IlS"/7
//
/7
/7//
//
//
//
/7/7
HYDRO
GEO
CHEM,INC.
3000
EXPLANATION
perched monitoring well showing
elevation in feet ams1
temporaryperched monitoringwell
showing elevation in feet amsl
perched piezometershowing
elevationinfeetams!
perched monitoringwell installed April,2005
showing elevationin feet amsl
temporaryperchedmonitoring well installed
A rH,2005 showin elevation infeetams!
N
1
o
MW-20.....
0548'
PIEZ·1
•5552
MW·31
+548.
~"2'
---5510
5500
T38S
T37S
(/
5490
....."".....-.....CELl'NO.2 - - - --5540".....-..........--5530NO.J ~......5021520
"""'II,
III,
""""""""""""'~..."'''<q.=._:=.=.:===..."..
•MW-3 PERCHED MONITORING WELL5471SHOWINGWATERLEVELINFEET AMSL
EXPLANAliON
W WILDLIFE POND
5580 WATER LEVEL CONTOUR LINE,
DASHED WHERE UNCERTAIN N
1,
0 3000
SCALE IN fEET
PERCHED WATER LEVELSAUGUST1990HYDRO
GEO
CHEM,INC.I-:A-ppr-owd-.,....."...,.----r::--:-:-"1r::-:"-~~---r;:F;;::IG:-:--.-4
55 3
"'22.5445
----5490
------5500
T38S----5480
.................._-
- - - - -5470
----+--------- --- ----5460
/I#~==-.a==:.1:.:.======:.======,f1
""2"""5450
,
"""""""III,
II"\~~\..::;20
"""""""'~Il;';========....':....
~""'~(r
"""""""-")!
""""""""""""""""""""""""",
•MW-3 PERCHED MONITORING WELL
5471 SHOWING WATER LEVEL IN FEET AMSL
EXPLANATlON
W WILDLIFE POND
5580 _
WATER LEVEL CONTOUR LINE,
DASHED WHERE UNCERTAIN N
1
o 3000SCALEINfEET
HYDRO
GEO
CHEM,INC.Approved
SS
PERCHED WATER LEVELSAUGUST1994
4
o:::r 5490
~-5480
---5470
..........
".....
•~41 ............._
---t--------:-------5460 ,f4"'\,*$S==_:_===_==-===:====:==•••===="':'
l:t:t:-.a..<::J
'\_.~
""""""I,"'I"I,""I,I,"'~...'\.:==-=====-...,..
.......1.P-1~'"e~7a
28 ...._--5580
/~5590/ /-"-'i//h',
I I I '-'\,.....-Ir-.-,g e~,~I
iRt1J I
SIT!I 'V I
\\.~...'/bbq,o
•MW-11 PERCHED MONITORING WELL
5514 SHOWING WATER LEVEL IN FEET AMSL
EXPLANATION
o 5524 TEMPORARY PERCHED MONITORING WELL
SHOWING WATER LEVEL IN FEET AMSL
~P-5 PIEZOMETER
5533 SHOWING WATER LEVEL IN FEET AMSL
5580 WATER LEVEL CONTOUR LINE.
DASHED WHERE UNCERTAIN
W WILDLIfE POND
N
1
5
SCALE IN FEETo
PERCHED WATER LEVELSSEPTEMBER2002HYDRO
GEO
CHEM,INC.~App-ro-_-:-I":"":'--r::-~"""'=-:--"""=-:----T.F::':IG::-:----I
SS
NOTE:WATER LEVELS FOR PIEZOMETERS
ARE FROM AUGUST.2002
6H:I718000lceIl4bIw10807.SIf
MW·22
MW·18_..
SJS
KRIGED 3rd QUARTER,2007 WATER LEVELS
WHITE MESA SITE
MW·01..7.
\\
\\
\\
HYDRO
GEO
CHEM,INC.
II~~4~==========~~===={
"-=
II
,4
//
,4
,4
,4
//
,4
,4
,4
,4
NOTES,Locationsand elevations for TW4-23,TW4-24,and TW4-25 areapproximate;
Water level for MW-26 (TW4-15)is fromthe second quarter,2007
3000
MW·03"'71
MW·20.,N
1
SCALE IN FEET
EXPLANATION
perchedmonitoring wellshowing
elevationinfeetamsl
temporary perchedmonitoring well
showingelevation in feet amsl
perchedpiezometer showing
elevationin feet amsl
perchedmonitoring well installed April,2005
showingelevation in feet amsl
temporaryperched monitoringwellinstalled
April,2005 showingelevation infeet amsl
temporaryperched monitoringwellinstalled
~ay,2007showing approximate elevation
I
A
If
II
11~1-.;:-~..:::.:::t-
MW·20....,
05550
PIEZ·'
•5591
MW·31
-+-5537
~5571
~553.
o
o 1000 2000 3000
SCALE IN FEET
7
FIG:
PORTION OF USGS BLACK MESA 7.5'SHEET SHOWING
APPROXIMATE LOCATION OF TAILING CELLS
GEO IN RELATION TO NEARBY CANYONS AND RUIN SPRING
CHEM,INC.Approvod
SS
HYDRO
\\
\\
\\
PIEZ·2
"3
PIEZ·3
'32
074
054
012
01.04.Ola
MW·10..,
PIEZ·1...
..•TW4-23
*PIEZ·5
'47
28
MW·27
+0'
MW·01
MW·17~.
CELL NO.1
32
I
A
If
II
11 /I~1.~~~y
8H:1718000/ceIl4b/dtw0807.srf
MW·22
DEPTHS TO WATER
3rd QUARTER,2007
WHITE MESA SITE
T38S
T37S
SJS
II_-_4 I;
~#---================p"~~-9'
HYDRO
GEO
CHEM,INC.
II
////
//
//
////
//
//
////NOTES:Locations of TW4-23, TW4-24,andTW4-25 are approximate;
Measurement forMW-26 (TW4.15)is from the second quarter,2007
3000
MW-03
MW·20~.N
1
SCALE IN FEET
EXPLANATION
perchedmonitoringwellshowing
depth infeet
temporary perchedmonitoringwell
showingdepthin feet
perchedpiezometershowing
depthinfeet
perchedmonitoring wellinstalledApril,2005
showingdepthin feet
temporaryperched monitoring well installed
April,2005showingdepth infeet
temporaryperched monitoring well installed
May,2007showing depthinfeet
MW·20.7.
071
PIEZ·'
••5
MW·31"7.-¢o57
~..
o
\\
\\
\\
01
PIEZ·3•••
02.
022
000
003
003000
MW·19eIl3
PIEZ·2...
.2•TW4-23
*PIEZ·s••0
T37S
28
MW-01
\\
\I
1\
II
II
MW·03..
J
I-
/I
II
II #~1.;:-~-=-.Y
9H:1718000/cell4b/satdthck.srf
MW-22
T38S
APPROXIMATE SATURATED THICKNESS
3rd QUARTER,2007
WHITE MESA SITE
SJS
II_-_4 II~~---================p"~-:-~
HYDRO
GEO
CHEM,INC.
II
.4
//
.4.4.4
.4
.4
//
//.4
NOTES:Locationsand values forTW4-23,TW4-24,and TW4-25 are approximate;
Value forMW-26(TW4-15)is based on the second quarter,2007 waterlevel
3000
MW·20"2N
1
SCALE IN FEET
EXPLANATION
perched monitoring wellshowing
saturatedthickness(feet)
temporary perched monitoring well
showing saturated thickness(feet)
perched piezometershowing
saturated thickness (feet)
perched monitoring weltinstalled April,2005
showing saturated thickness(feet)
temporary perched monitoring well installed
April,2005showing saturated thickness (feet)
temporaryperched monitoring well installed
May,2007 showing saturated thickness (feet)
o
MW·20.,.
0"
PIEZ·l..,
MW·31.,.
4057
~..
PIEZ·1.
MW·19•
PIEZ·3.
TW..llbTW4-11 OTW4-13TW4-~
OTW"1
OTW....OTW..14
OTW4-<l
TW4-20 OTW4-5
·26 TW4-1PW".o OTW"3 OTW4-12
*PIEZ-5.
MW·18•
T37S
28
MW-01•
MW-17•
CELLNO.2
CELL NO.1
MW·03•
MW·02•r!l.f~
;7 II
II
II
II;,il
II
II I CELL NO.48
I:I (PRf)POSED)
.JL 33(PROPOSEO>C>'MW·16(abandoned)jMil'"MW.34IPRO~D~~.
II 32 .f===~~~II
II
II
II
II
II
II
II
II
II
I
II
II
II
\1 II
~1-.:::-~~;:!-
PROPERTY
BOUNDARY
MW·22•
N
1
o
SCALE IN FEET
EXPLANATION
MW·20•perched monitoringwell
TW4-1to temporary perched monitoring well
MW·20•
3000
if wildlife pond
T38S
II_-_4 ;7
'"#- ---================7;'~~.-?'
II
//
#
//
////
#
#
//
//
//
SITE PLAN SHOWING EXISTING
AND PROPOSED PERCHED WELL LOCATIONS
WHITE MESA SITE
PIEZ·1•
TW4-23~
MW·33
()
perched piezometer
newtemporary perchedmonitoring well
installed MaY,2007(locations approximate)
proposedtemporaryperched monitoring well
HYDRO
GEO
CHEM,INC.
SJS H:l718000/cell4b/propwell.srf 10
Appendix B
PROPOSED DEVELOPMENT OF NEW TAILINGS CELL
4B FOR THE WHITE MESA URANIUM MILL
Prepared for:
Denison Mines (USA)Corp.(DUSA)
Prepared by:
SENES Consultants Limited
121 Granton Drive,Unit 12
Richmond Hill,Ontario
L4B3N4
April 2008
Printed on Recycled Paper Containing Post~Consumer Fibre
Proposed Development ofNew Tailings Cell 4Bfor White Mesa Uranium Mill
EXECUTIVE SUMMARY
Denison Mines (USA)Corp.(DUSA)operates the White Mesa Uranium Mill (hereafter refelTed
to as the "mill")in San Juan County,Utah,approximately 6 miles (9.6 km)south of the city of
Blanding.The mill is located on a parcel of land and mill site claims covering approximately
5,415 acres (2,191 hal.The mill is licensed by the State of Utah Division of Radiation Control
(DRC)to process uranium ore and selected alternate feed materials.
In February 2007,SENES prepared a dose assessment for DUSA in support of the license
renewal application for the mill (SENES 2007,also referred to as the previous report).
MILDOS-AREA was used to estimate the dose commitments that could potentially be received
by individuals and the general population within a 50 mile (80 km)radius for processing of
conventional ores.The assessment was prepared for scenarios in which Colorado Plateau
(0.25%U30 S and 1.5%V20S)or Arizona Strip (0.637%U30s and no V20S)ores are processed at
the mill.
This dose assessment extends the analyses ofthe previous report of February 2007 to incorporate
the dose from the proposed development of new tailings Cell 4B,anticipated to be completed for
use in 2009,in support of a license amendment application by DUSA for construction and
operation of that cell.In doing the dose assessment for Cell 4B,we have updated the
assumptions we used in February 2007 for modeling tailings Cells 1,2,3 and 4A to reflect the
cun'ent operational status ofthe site,including the re-commissioning of Cell 4A for use in 2008.
For purposes of modeling mill operations,we have separated operations into two phases.Phase
1 involves the continued use of Cell 1 for solution evaporation,the continued use of Cell 3 for
solution evaporation and the disposal of tailings solids,and the use of Cell 4A for disposal of
tailings solids and solution evaporation.Phase 2 occurs after Cell 3 is full and is no longer an
active cell.During Phase 2,Cells 4A and 4B are used for disposal of tailings solids and solution
evaporation,and Cell 1 is used for solution evaporation.In each Phase,Cell 2,with interim soil
cover over the entire cell area,is included in the model,and in Phase 2,Cell 3,with interim soil
cover over the entire cell area,is included in the model.
The United States Nuclear Regulatory Commission (NRC)-approved MILDOS-AREA was used
to estimate the dose commitments received by individuals and the general population within a 50
mile (80 km)radius of the site for the processing of either Colorado Plateau or Arizona Strip ore
separately.In each scenario,the doses arising from emissions of dust and radon from the mill
area (excluding the tailings cells)and ore pads were assumed to be the same as the previous 2007
report since the scenarios both involve the processing of Colorado Plateau and Arizona Strip
ores.Therefore,MILDOS-AREA runs fi'om the previous report were revised to exclude the
tailings cells.The doses from the tailings cells were estimated in separate MILDOS-AREA runs
34489-10··FINAL-April200S ES-l SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4Bfor White Mesa Uranium Mill
and added to the dose from the mill area and ore pads.Table ES-I provides a summary of the
source terms included in Phases I and 2 ofthe development ofnew tailings cells.
TABLE ES-l
SOURCE TERMS INCLUDED IN PHASES 1 AND 2
Source Term Phase 1 Phase 2
Mill area included included
Ore Pads included included
Tailings Cell 2 with Interim Soil Cover included included
Tailings Cell 3 active interim soil cover
Tailings Cell 4A active active
Tailings Cell4B excluded active
The wind erosion and radon release rates from the tailings cells (active and with interim soil
cover)were modelled by using a maximal worst case approach.
Each active tailings cell was modelled to have an active exposed (non-solution)tailings solids
area of 10 acres (i.e.,the maximum uncovered tailings solids area at any time allowed under
NESHAPs Regulation 40 CFR 61.252(b),Subpart W)since it is not possible to predict the
distribution of uncovered tailings between the active cells at any given time.As a result,the
release rate of wind-eroded tailings dust was estimated at 10 acres at all times for each active
cell.We understand that during the active life of each cell,the average exposed tailings solids
will be less than 10 acres,so this assumption is considered to be conservative.The total annual
radon release rate was estimated by assuming a radon release rate of20 pCi/m2s (i.e.,maximum
radon-222 emissions to ambient air from an existing uranium mill pile)over the entire area of
each cell consistent with NESHAPs.Actual radon emission rates from the tailings cells have
historically been well below 20 pCi/m2s,so this assumption is also considered to be
conservative.
Emissions fi'om the tailings cells (2 and 3)with interim soil cover were assumed to occur over
the entire area of each cell;however,only radon is released at a rate of 10 pCi/m2s after the
application of the soil cover.
The calculated total annual effective dose commitments (including radon)calculated using
MILDOS-AREA were compared to the Utah Administrative Code R313-15-30I(1)(a)
requirement that the dose to individual members of the public shall not exceed 100 mrcm/yr
(radon included).For the processing of Colorado Plateau ore,the maximum total annual
effective dose commitments was calculated to be a maximum of 1.4 mrem/yr for an infant at the
nearest potential resident,BHY-l (Tables 6.1-1 and 6.1-3)(i.e.,effective dose)and is about
1.4%ofthe R313-l5-30l(1)(a)limit of 100 mrem/yr (radon included)to an individual member
34489-10-FINAL -April 2008 ES-2 SENES Consultants Limited
Proposed Development o/New Tailings Cell4B/or White Mesa Uranium Mill
of the public,for Phases I and 2.For the processing of Arizona Strip ore,the total annual
effective dose commitments were calculated to be a maximum of 3.1 mrem/yr for an infant at the
nearest potential resident,BHV-I (Tables 6.2-1 and 6.2-3)(i.e.,effective dose)and is about
3.1 %of the 100 mrem/yr limit (radon included)to an individual member of the public,for
Phases I and 2.Overall,using conservative assumptions,the predicted annual effective dose
commitments for Phases I and 2 comply with R313-15.
In addition,our MILDOS-AREA calculated 40 CFR 190 annual dose commitments (excluding
radon)were compared to the 40 CFR 190 criterion,which is 25 mrem/yr to the whole body
(excluding the dose due to radon)and 25 mrem/yr to any other organ to any member of the
public (EPA 2002).The 40 CFR 190 doses were also used to demonstrate compliance with the
ALARA (As Low As Reasonably Achievable)goal set out in R313-15-101(4)(10 CFR
20.1101(d»(i.e.,the ALARA goal is to demonstrate that total effective dose equivalent to the
individual member of the public likely to receive the highest total effective dose equivalent will
not exceed 10 mrem/yr (absent of the radon dose».For the processing of Colorado Plateau ore,
the 40 CFR 190 annual dose commitments were calculated to be a maximum of 4.8 mrem/yr for
a teenager at the nearest potential resident,BHV-I (Tables 6.1-5 and 6.1-8)(i.e.,dose to the
bone)and is about 19%of the 40 CFR 190 dose criterion of 25 mrem/yr,for Phases I and 2.
Further,the 40 CFR 190 annual effective dose commitments demonstrate compliance with the
R313-15-101(4)(10 CFR 20.IIOI(d»ALARA goal of 10 mremlyr to the individual member of
the public likely to receive the highest total effective dose equivalent (the maximum total
effective dose equivalent (radon excluded)during Phases I and 2 was 0.545 mrem/yr for an
infant at BHV-I.).For Arizona Strip ore,the 40 CFR 190 annual dose commitments were at
most 12 mrem/yr for a teenager at the nearest potential resident,BHV-I (Tables 6.2-5 and 6.2-8)
(i.e.,dose to the bone)and is about 49%of the 40 CFR 190 dose criterion of 25 mrem/yr for
Phases I and 2.Further,the 40 CFR 190 annual effective dose commitments demonstrate
compliance with the R313-15-101(4)(10 CFR 20.IIOI(d»ALARA goal of 10mrem/yr to the
individual member of the public likely to receive the highest total effective dose equivalent (the
maximum total effective dose equivalent (radon excluded)during Phases I and 2 was
1.39 mrem/yr for an infant at BHV-I).Overall,using conservative assumptions,ore processing
in Phases I and 2 comply with the requirements of40 CFR 190 and the ALARA goal set out in
R313 -15-101(4).
34489-10 -FINAL -Apl'il2008 ES-3 SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4Bfor White Mesa Uranium Mill
TABLE OF CONTENTS
Page No.
EXECUTIVE SUMMARY ES-I
ACRONYMS &ABBREViATIONS AC-I
1.0 INTRODUCTION I-I
1.1 Background ,I-I
1.2 Objective 1-2
1.3 Approach 1-2
1.4 Contents OfThis Report 1-3
2.0 REGULATORY COMPLIANCE 2-I
3.0 RADIATION DOSE ASSESSMENT 3-1
3.1 General Information About MILDOS-AREA 3-1
3.2 The Use ofMILDOS-AREA In This Assessment..3-1
4.0 SOURCE TERMS 4-1
4.1 Point Sources 4-3
4.I.I Grinder 4-3
4.1.2 Grizzly 4-3
4.1.3 Yellowcake Stacks 4-4
4.1.4 Vanadium Stack 4-4
4.2 Area Sources 4-5
4.2.1 Ore Pads 4-5
4.2.2 Tailings Cells 4-6
4.3 Meteorological Data 4-8
4.4 Population Data 4-8
4.5 Uranium Mill Source Emission Rates 4-9
4.5.1 Colorado Plateau Ore 4-9
4.5.2 Arizona Strip Ore 4-9
5.0 RECEPTORS 5-1
6.0 RADIATION DOSE ESTIMATES 6-I
6.1 MILDOS-AREA Results For Colorado Plateau Ore 6-2
6.1.1 R313-15-30I(l)(a)Regulatory Compliance 6-2
6.1.2 40 CFR 190 Regulatory Compliance 6-9
6.2 MILDOS-AREA Results for Arizona Strip Ore 6-19
6.2.1 R313-15-301 (l)(a)Regulatory Compliance 6-19
6.2.2 40 CFR 190 Regulatory Compliance 6-26
7.0 KEY OBSERVATIONS 7-1
8.0 REFERENCES 8-1
34489-10-FINAL -April 2008 SENES Consultants Limited
Proposed Development ofNew Tailings Ce1l4B for White Mesa Uranium Mill'--_
LIST OF APPENDICES
Page No.
APPENDIX A HISTORY OF MILDOS A-I
APPENDIX 8 EMISSION CALCULAnONS 8-1
8.1 Calculation ofAnnual Dust Loss 8-1
8.2 Emission Calculations 8-2
APPENDIX C MILDOS-AREA RESULTS C-I
C.I MILDOS-AREA Results for Colorado Plateau Ore C-I
C.I.!R313-15-301 (l)(a)RegulatoryCompliance C-1
C.2 MILDOS-AREA Results for Arizona Strip Ore C-7
C.2.1 R313-15-301 (l)(a)Regulatory Compliance C-7
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Proposed Development ofNew Tailings Cell 4Bfor White Mesa Uranium Mill
LIST OF TABLES
Page No.
ES-l Source Terms Included in Phases 1 and 2 ES-2
1.3-1 Source Terms Included in Phases 1 and 2 1-3
4.2-1 Characteristics ofTailings Cells in Phase 1 4-6
4.2-2 Characteristics ofTailings Cells in Phase 2 4-6
4.5-1 Radioactive Patticulate and Radon Emission Rates (Colorado Plateau Ore)4-9
4.5-2 Radioactive Particulate and Radon Emission Rates (Arizona Strip Ore)4-10
6.1-1 Phase I-Comparison ofAnnual Dose Commitments with Applicable Radiation
Protection Standards (Colorado Plateau Ore)6-3
6.1-2 Phase I-Total Annual Dose Commitments for Meat Ingestion Pathway
(Colorado Plateau Ore)(mrem/yr)6-6
6.1-3 Phase 2-Comparison ofAnnual Dose Commitments with Applicable Radiation
Protection Standards (Colorado Plateau Ore)6-6
6.1-4 Phase 2-Total Annual Dose Commitments for Meat Ingestion Pathway
(Colorado Plateau Ore)(mrem/yr)6-9
6.1-5 Phase I-Comparison of40 CFR190 Annual Dose Commitments with Applicable
Radiation Protection Standards (Colorado Plateau Ore)6-10
6.1-6 Phase 1-40 CFR190 Annual Dose Commitments for Meat Ingestion
Pathway (Colorado Plateau Ore)(mrem/yr)6-13
6.1-7 Phase 2-Annual Population Dose Commitments within 50 miles (80 km)of the
Mill for Colorado Plateau Ore 6-13
6.1-8 Phase 2-Comparison of40 CFR190 Annual Dose Commitments with Applicable
Radiation Protection Standards (Colorado Plateau Ore)6-15
6.1-9 Phase 2-40 CFR190 Annual Dose Commitments for Meat Ingestion
Pathway (Colorado Plateau Ore)(mrem/yr)6-18
6.1-10 Phase 2-Annual Population Dose Commitments within 50 miles (80 km)ofthe
Mill for Colorado Plateau Ore 6-18
6.2-1 Phase I-Comparison ofAnnual Dose Commitments with Applicable Radiation
Protection Standards (Arizona Strip Ore)6-20
6.2-2 Phase I-Total Annual Dose Commitments for Meat Ingestion Pathway
(Arizona Strip Ore)(mrem/yr)6-23
6.2-3 Phase 2-Comparison ofAnnual Dose Commitments with Applicable Radiation
Protection Standards (Arizona Strip Ore)6-23
6.2-4 Phase 2-Total Annual Dosc Commitments for Meat Ingestion Pathway
(Arizona Strip Ore)(mrem/yr)6-26
6.2-5 Phase I-Comparison of40 CFR190 Annual Dose Commitments with Applicable
Radiation Protection Standards (Arizona Strip Ore)6-27
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LIST OF TABLES
Page No.
6.2-6 Phase 1-40 CFR 190 Annual Dose Commitments for Meat Ingestion
Pathway (Arizona Strip are)(mrem/yr)6-30
6.2-7 Phase I-Annual Population Dose Commitments within 50 miles (80 km)ofthe
Mill for Arizona Strip are 6-30
6.2-8 Phase 2-Comparison of40 CFR190 Annual Dose Commitments with Applicable
Radiation Protection Standards (Arizona Strip are)6-3 I
6.2-9 Phase 2-40 CFR190 Annual Dose Commitments for Meat Ingestion
Pathway (Arizona Strip are)(mrem/yr)6-34
6.2-10 Phase 2-Annual Population Dose Commitments within 50 miles (80 km)ofthe
Mill for Arizona Strip are 6-34
7-1 Source Teillis Included in Phases I and 2 7-1
B.I Parameter Values for Calculation ofAnnual Dusting Rate for Exposed Tailings 8-I
C.I-I Annual Dose Commitments (Colorado Plateau Ore)C-I
C.I-2 40 CFR 190 Annual Dose Commitments (Colorado Plateau are)C-4
C.2-1 Annual Dose Commitments (Arizona Strip Ore)C-7
C.2-2 40 CFR 190 Annual Dose Commitments (Arizona Strip Ore)C-IO
LIST OF FIGURES
Page No.
4.I Source Locations 4-2
5.1 Receptor Locations 5-2
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Proposed Development ofNew Tailings Cell 4Bfor White Mesa Uranium Mill
ACRONYMS &ABBREVIATIONS
ALC
ANL
ALARA
Avg.
ASCII
Bi-210
Bi-2l4
CCD
CFR
Ci
DCF
DRC
DUSA
EPA
Ew
F
FES
Fs
ft
ft3
g
gore
GPS
GUI
ha
hI'
lCRP
ID
lbs
km
kts
NESHAPs
NRC
NUREG
m
m2
mrem
MPC
Allowable Concentration
Argonne National Laboratory
As Low As Reasonably Achievable
average
American Standard Code for Information Interchange
bismuth-210
bismuth-2l4
Counter Current Decantation
Code ofFederal Regulations
cune
Dose Conversion Factor
State ofUtah Division of Radiation Control
Denison Mines (USA)Corp.
United States Environmental Protection Agency
Process Emission Factor
Radon Release Rate
Final Environmental Statement
annual fi'equency ofoccurrence ofwind group S
feet
cubic feet
grams
grams ofore
Global Positioning System
Graphical User Interface
hectares
hours
International Commission on Radiological Protection
Induced Draft
pounds
kilometers
knots
National Emission Standards for Hazardous Air Pollutants
United States Nuclear Regulatory Commission
Regulatory Guide
meters
square meters
millirem
Maximum Pelmissible Concentration
34489·10···FINAL·April 2008 AC-l SENES Consultants Limited
___-"-P_r0-!C'Posed Development ofNew Tailings Cell 4Bfor White Mesa Uranium Mill
Pb-21 0
Pb-214
pCi
Po-210
Po-218
Ra-226
Rn-222
Rs
s
S
SENES
TGLM
Th-230
tpy
U30g
Unat
U-234
U-235
U-238
V20S
yd3
yr
lead-210
lead-214
picocurie
polonium-210
polonium-218
radium-226
radon-222
Resuspension rate for wind group S
seconds
Radionuclide Emission Rate
Specialists in Energy,Nuclear and Environmental Sciences
Task Group on Lung Dynamics Lung Model
thorium-230
tons per year
triuranium octoxide ("Yellowcake")
natural uraniurn
uranium-234
uranium-235
uranium-238
vanadium pentoxide
cubic yards
year
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Proposed Development ofNew Tailings Cell 4B for White Mesa Uranium Mill
1.0 INTRODUCTION
1.1 BACKGROUND
Denison Mines (USA)Corp.(DUSA)operates the White Mesa Uranium Mill (hereafter referred
to as the "mill")in San Juan County,Utah,approximately 6 miles (9.6 km)south of the city of
Blanding.The mill is located on a parcel of land and mill site claims covering approximately
5,415 acres (2,191 ha).The mill was built in 1979 and licensed by the United States Nuclear
Regulatory Commission (NRC)to process uranium ore and selected alternate feed materials.
The mill began operations in July 1980.In August 2004,the State of Utah became an
Agreement State for the regulation of uranium mills,and primary regulatory authOlity over the
mill was assumed by the State ofUtah Division of Radiation Control (DRC)at that time.
The mill is a standard design with both uranium and vanadium circuits and uses the acid leach-
solvent extraction process for uranium recovery from uranium ores and uranium/vanadium ores.
Vanadium in uranium/vanadium-bearing ores is partially solubilized during leaching,and the
dissolved vanadium present in uranium raffinate is fuliher processed for recovery of vanadium
before recycling (NRC1979).
In the early 1990s,the mill began receiving "alternate feed material"(uranium-bearing materials
other than conventionally mined ores)for processing.From 1999 to present,the mill has relied
solely on alternate feed materials.The mill goes on standby for periods of time and then it
processes the stockpiled alternate feeds for the recovery of uranium.The residual tailings from
these processes are stored in the tailings cells on-site.DUSA has commenced mining activities
in the Colorado Plateau district and conventional ores are being hauled and stockpiled at the mill.
In addition,DUSA has mining assets in the Arizona Strip,and mining of those ores is expected
to commence in 2008.Milling of conventional ore is scheduled for Spring 2008,when the
milling ofcUlTently available alternate feed material is completed (DUSA 2007a).
In Febmary 2007,SENES prepared a dose assessment for DUSA in support of the license
renewal application for the mill (SENES 2007,also referred to as the previous repoli).
MILDOS-AREA was used to estimate the dose commitments that could potentially be received
by individuals and the general population within a 50 mile (80 km)radius for the processing of
Colorado Plateau or Arizona Strip ores separately.(MILDOS-AREA is an NRC approved code
designed as a tool to provide input on regulatory and compliance evaluations for various uranium
recovery operations.)The following assumptions were used in the previous report:
•Colorado Plateau ore contains an average of 0.25%U30 8 and 1.5%V20 S (NRC 1980).
The vanadium content in the ore is fuliher processed for recovery before recycling.
•Arizona Strip ore contains 0.637%U30 8 and no vanadium (Landau 2007).
34489·10-FINAL -Apri12008 I-I SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4Bfor White Mesa Uranium Mill
•The activity concentrations of U-238 in Colorado Plateau and AJizona Strip ore were
700 and 1783 pCi U-238/g ore,respectively.
•The proposed ore process rate was assumed to be 730,000 tons per year (tpy)(an average
of2,000 tons per day).Therefore,assuming that the average uranium recovery would be
at the historical recovery yield of94%,approximately 1,715 tons (3,431,000 Ibs)ofU308
per year would be recovered fi·om Colorado Plateau ore at the proposed ore process rate.
Similarly,approximately 4,371 tons (8,742,000 Ibs)ofU30 8 per year would be recovered
fi·om Arizona Strip ore at the proposed ore process rate.
1.2 OBJECTIVE
The objective of this report is to extend the analyses ofthe previous report of February 2007 to
incorporate the dose from the proposed development of new tailings Cel!4B,anticipated to be
completed for use in 2009,in support of a license amendment application by DUSA for
construction and operation of that cell.In doing the dose assessment for Cel!4B,we have
updated the assumptions we used in February 2007 for modeling tailings Cells 1,2,3 and 4A to
reflect the CutTent operational status of the site,including the re-commissioning of Cel!4A for
use in 2008.Otherwise,we have made as few changes to the 2007 calculations as possible.
MILDOS-AREA was used to estimate the dose commitments that could potential!y be received
by individuals and the general population within a 50 mile (80 km)radius of the site for the
processing of Colorado Plateau or Arizona Strip ores using the assumptions provided in
Section 1.1.
1.3 ApPROACH
The approach used for this assessment was to extend the previous report to incorporate the dose
fi·om the proposed development of Cell 4B,with as few changes to the calculations as possible.
For purposes of modeling mill operations,we have separated operations into two phases.
Phase 1 involves the continued use of Cell 1 for solution evaporation,the continued use ofCel!3
for solution evaporation and the disposal of tailings solids and the use of Cell 4A for disposal of
tailings solids and solution evaporation.Phase 2 occurs after Cell 3 is full and is no longer an
active cell.Phase 2 involves the use of Cell 1 for solution evaporation and Cells 4A and 4B for
disposal of tailings solids and solution evaporation.In each Phase,Cell 2,with interim soil
cover over the entire cell area,is included in the model,and in Phase 2,Cell 3,with interim soil
cover over the entire cell area,is included in the model.
Since there are two types of ore,MILDOS-AREA runs were created to assess the dose from
processing of the Colorado Plateau and Arizona Strip ores separately (hereafter refelTed to as
Scenario 1 and 2,respectively).Each scenari%re was analyzed with the following separate
MILDOS-AREA runs:
34489-10 -FINAL -April 2008 1-2 SENES Consultants Limited
Proposed Development ofNew Tailings Cell4Bfor White Mesa Uranium Mill
•Tailing Cell 2 with Interim Soil Cover;
•Tailings Cell 3 with Interim Soil Cover;
•Tailings Cell 3;
•Tailings Cell 4A;
•Tailings Cell 4B;and
•All source terms (at the mill including the ore pads)except for tailings cells (hereafter
referred to as the mill area).
The dose from each tailings cell was calculated in separate MILDOS-AREA runs to allow for the
flexibility of calculating the incremental doses from the different combination oftailings cells to
the mill area and ore pads for the two anticipated development Phases.Table 1.3-1 provides a
summary ofthe source terms included in Phases I and 2 ofthe development ofnew tailings cells.
TABLE 1.3-1
SOURCE TERMS INCLUDED IN PHASES 1 AND 2
Source Term Phase I Phase 2
Mill area included included
Ore Pads included included
Tailings Cell 2 with Interim Soil Cover included included
Tailings Cell 3 active interim soil cover
Tailings Cell4A active active
Tailings Cell4B excluded active
1.4 CONTENTS OF THIS REPORT
The remainder of this report is alTanged into seven sections.
Section 2.0,Regulatory Compliance,provides a description of the regulatory framework
peliaining to the applicable dose limits to members of the public from licensed activities at the
mill.
Section 3.0,Radiation Dose Assessment,describes the method used to estimate the radiation
doses to members ofthe public and how MILDOS-AREA was used.
Section 4.0,Source Terms,describes the source telms and source emission rates related to the
ore processing operations and other input parameters required (i.e.,meteorological data and
population data)for the MILDOS-AREA runs.The source emission rates were calculated for
processing Colorado Plateau and Arizona Strip ores based on the ore grade,ore process rate and
uranium recovery yield described in Section 1.1.
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Proposed Development ofNew Tailings Cell 4Bfor White Mesa Uranium Mill
Section 5.0,Receptors,describes the receptors used in the MILDOS-AREA mns.
Section 6.0,Radiation Dose Estimates,provides the dose results from the MILDOS-AREA
runs using the parameters described in Sections 4.0 and 5.0.
Section 7.0,Overviews,provides a summary of the dose estimates for the two Phases in each
scenano.
Section 8.0,References,provides a list of reference material used to prepare this report.
Appendix A:History of MILDOS-AREA,describes how the MILDOS-AREA software has
evolved,highlighting some ofthe key differences between the updated version,MILDOS-AREA
(ANL 1998a),and the original version ofMILDOS.
Appendix B:Emissions Calculations,describes the basis of the emission estimates for each
source.
Appendix C:MILDOS-AREA Results,provides the dose estimates for MILDOS-AREA runs
for the mill area (induding the ore pads)and each tailings cell.
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Proposed Development ofNew Tailings Ce1l4Bfor White Mesa Uranium Mill
2.0 REGULATORY COMPLIANCE
DRC has the regulatory authority over the license issued for the site.As required by Utah
Administrative Code R313-15-101(2),the mill shall,to the extent practical,employ procedures
and engineering controls based upon sound radiation protection principles to achieve
occupational doses and doses to members ofthe public that are as low as reasonably achievable
(ALARA).Under R313-15-30I(l)(a),the licensee is required to demonstrate that the total dose
equivalent to individual members of the public from the licensed operation does not exceed
0.1 rem (100 mrem)in a year (including radon),exclusive ofthe dose contribution fj'01TI natural
background and medical sources.Under 10 CFR 20.1301 (NRC 1991),NRC has adopted the
provisions ofthe United States Environmental Protection Agency (EPA)environmental radiation
standards in 40 CFR 190 (EPA 2002).This subpart requires that the licensee provide reasonable
assurance that the radiation attributed to mill operations does not exceed the annual dose of
25 mrem/yr to the whole body,75 mrem/yr to the thyroid and 25 mrem/yr to any other organ of
any member of the public (radon and it daughters excepted).In addition,10 CFR 20.1301 (d)
(R313-15-IOI(4))sets an ALARA goal on air emissions of radioactive material to the
environment,excluding radon-222 and its daughters such that the individual member of the
public likely to receive the highest total effective dose equivalent will not exceed 10 mrem/yr.
34489-10-FINAL-April 2008 2-1 SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4B for White Mesa Uranium Mill
3.0 RADIAnON DOSE ASSESSMENT
3.1 GENERAL INFORMATION ABOUT MILDOS-AREA
MILDOS-AREA only considers airborne releases of radioactive materials;releases to surface
water and groundwater are not addressed.The U-238 decay chain was assumed to be the only
significant source of radiation fi'om uranium milling operations (the radioactivity contribution
from the U-235 chain is less than 5%of that from the U-238 chain).The pmticulate releases
include U-238,Th-230,Ra-226 and Pb-210.The gaseous releases are defined for Rn-222 with
in-growth of short-lived daughter products also considered.These Rn-222 daughters include
Po-218,Pb-214,Bi-214,Pb-21 0 and Po-21 O.The model accounts for the releases and in-growth
ofother radionuclides using the assumption ofsecular equilibrium within the U-238 decay chain.
The transport ofmodel radiological emissions from the point and area sources is predicted using
a sector-averaged Gaussian plume dispersion model.The dispersion model uses the
meteorological data provided by the user and also includes mechanisms of dry deposition of
pmticulates,re-suspension,radioactive decay and progeny in-growth and plume reflection.
Deposition build-up and in-growth of radioactive progeny are considered in estimating ground
concentrations.
The impacts to humans through various pathways are estimated based on the calculated annual
average air concentrations of radionuclides.The pathways considered in this analysis include:
inhalation,external exposure from ground concentrations,external exposure from cloud
immersion,and ingestion ofmeat and vegetables.
3.2 THE USE OF MILDOS-AREA IN THIS ASSESSMENT
As described in Section 1.3,the approach for this assessment was to extend the previous report
(SENES 2007)to incorporate the dose from the proposed development of Cell 4B,with as few
changes to the calculations as possible.MILDOS-AREA (version 2.20[3 (ANL 1998a»was used
to estimate potential radiation doses to members of the public estimated from the processing of
Colorado Plateau or Arizona Strip ores,with separate runs for each scenari%re.(Information
about the history of MILDOS-AREA is provided in Appendix A).In Scenario I,1,715 tons
(3,430,100 Ibs)ofUJOs per year of Colorado Plateau ore would be recovered at the proposed ore
process rate of 730,000 tpy (assuming that the average uranium recovery is 94%).Similarly in
Scenario 2,4,371 tons (8,742,000 Ibs)ofU30s per year of Arizona Strip ore would be recovered.
In order design a conceptual model of the mill,MILDOS-AREA requires the user to define
source and receptor locations and source emissions.The locations of sources and receptors are
defined in MILDOS-AREA by providing Cartesian coordinates of the source/receptor relative to
34489-10 -FINAL-Apr;12008 3-1 SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4Bfor Whit~Mesa Uranium Mill
a reference point.The coordinates ofa point source are entered directly while the user must enter
vertex coordinates for an area source.
In this assessment,the location of all sources (except for the tailings cells)and receptors were
taken from the previous report.The coordinates relative to the vanadium stack (i.e., the
reference point for the site)were determined by plotting the GPS coordinates (provided by
DUSA (Turk 2007a»in Google Earth Pro (Google 2005).A description of the tailings cells is
provided in Section 4.0.The source emissions were calculated using guidance from NRC
Regulatory Guide 3.59 (NRC 1987)and NUREG-0706 (NRC 1980).Radionuclide emission for
radioactive particulates and radon are entered directly for point sources.For area sources,
MILDOS-AREA calculates the radionuclide emission for radioactive particulates and radon
based on the release rates and source area.
Since all source terms except for the tailings cells were taken £i'om the previous report,the
MILDOS-AREA run (from the previous report)for each scenario was revised to include all
source terms except for the tailings cells.(Descriptions and emission rates for each source are
provided in Section 4.0,and detailed emission estimates can be found in Appendix B.)The
tailings cells were re-modelled individually in MILDOS-AREA as large area sources.
Descriptions and emission rates for each cell are provided in Section 4.0,and detailed emission
estimates are provided in Appendix B.
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Proposed Development ofNew Tailings Ce1l4Bfor White Mesa Uranium Mill
4.0 SOURCE TERMS
The radionuclides of concern for the MILDOS-AREA model include:U-238 and its daughters
Th-230,Ra-226,Pb-210 and Rn-222,which were assumed to be in secular equilibrium with the
ore.The radioactive particulates and radon are emitted from airborne radioactive releases related
to dust generation during ore handling (unloading ore from truck to ore pads and loading ore to
the grizzly),point sources (grinder,yellowcake stacks and vanadium stack (only Scenario 1))
and area source dusting from ore pad stockpiles and the tailings cells.As mentioned in Section
3.2,all source telms except for the tailing cells were taken from the previous report.The
locations of all point sources except for the grinder were determined by plotting the GPS
coordinates (provided by DUSA (Turk 2007a))in Google Earth Pro;and then using the
measuring tool to measure the easting,nOithing and elevation of each source relative to a
reference point at the mill (i.e.,the vanadium stack).
The tailings cells were modelled as large area sources in MILDOS-AREA and located at the top
centre of each cell.Figure 4.1 shows the locations (plotted in Google Emth)of all sources used
in this assessment.
34489-10·-FINAL ~April 2008 4-1 SENES Consultants Limited
Proposed Development ofNew Tailings Ce1l4Bfor White Mesa Uranium Mill
FIGURE 4.1
SOURCE LOCATIONS
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Proposed Development ofNew Tailings Cell4Bfor White Mesa Uranium Mill
The doses to members of the public were estimated for the processing of Colorado Plateau or
Arizona Strip ore in separate scenarios/runs.Therefore,the emission calculations are provided
for each ore type based on the activity concentration of U-238 in the ore,expected ore grade,
average uranium recovery and the proposed ore process rate.The MILDOS-AREA model for
Colorado Plateau ore has an additional point source (i.e.,vanadium stack)since the ore may
contain vanadium (assumed at 1.5%V20 S).The approaches used to calculate the emissions from
the point and area sources are described in Sections 4.1 and 4.2,respectively.Detailed source
emissions calculations for al1 source terms are provided in Appendix B.
4.1 POINT SOURCES
Mill point sources used in this assessment include the grinder,loading ore to the grizzly and
yel10wcake stacks (north and south).The vanadium stack described in Section 4.1.4 is exclusive
to the processing of Colorado Plateau ore.A description of the approach used to calculate the
emissions from point sources is provided in this section.
4.1.1 Grinder
There is no on-site crushing ofthe ore,only a wet grinding operation.The ore dust emissions are
control1ed because the material is wet during the grinding operations.The particulate emission
control from the grinding operation was assumed to be 99.9%(EnecoTech 1991a and 1991b).
With these assumptions,U-238 and its decay daughters (assuming secular equilibrium)would be
emitted at a rate of 9.27E-05 and 2.36E-04 Ci/yr for Colorado Plateau and Arizona Strip ore,
respectively.The emission rates for Rn-222 released during wet grinding was calculated
assuming that only 20%of the radon is available for release or emanation from the mineral
grains in which it is produced (NRC 1980).The Rn-222 concentration in the ore was assumed to
be equal to the U-238 concentration.The Rn-222 released during wet grinding is 92.7 and 236
Cilyr for Colorado Plateau and Arizona Strip ore,respectively.
4.1.2 Grizzly
The emissions fi'om !lucks dumping ore onto the gtizzly are highly control1ed;the truck dump
area is enclosed on three sides and has a negative pressure on it during dumping activities.The
ore is delivered wet with an average moisture content of 10%.The exhaust fi'om the induced
draft (ID)fans used on the grizzly is ducted through a baghouse (EnecoTech 1991a and 199Ib).
The combined particulate dust control on this operation was assumed to be 99.9%(EnecoTech
1991a and 1991b).With these assumptions,U-238 and its decay daughters (assuming secular
equilibrium)would be emitted at a rate of 9.27E-05 and 2.36E-04 Ci/yr for Colorado Plateau and
Arizona Strip ore,respectively.
34489-10 -FINAL -April 2008 4-3 SENES Consultants Limited
Proposed Development o/New Tailings Ce1l4B/or White Mesa Uranium Mill
4.1.3 Yellowcake Stacks
The mill has two yellowcake dryers (north and south yellowcake dryers).From the EnecoTech
analysis,stack tests on the yellowcake dryer yielded a yellowcake emission rate of 0.06 Ibs/hr
U30 8 when the process rate was 1300 Ibs/hr.This yields an emission rate of 0.092 Ibs/hr of
yellowcake per ton of feed (EnecoTech 1991a and 1991b).The emission rate is with all the
particulate emissions controls.Since there are north and south yellowcake dryers,the stack
emissions from U-238 and its decay daughters are assumed to be divided equally between the
two (i.e.,north and south yellowcake stacks).With these assumptions,U-238 would be emitted
at a rate of 1.01 E-02 and 2.36E-04 Ci/yr for Colorado Plateau and Arizona Strip ore,
respectively.
Based on field measurements,the decay daughters of U-238 (Th-230,Ra-226 and Pb-2IO)are
processed along with yellowcake at 0.22%,0.13%and 0.78%ofU-238,respectively (EnecoTech
1991a and 199Ib).Therefore,the decay daughters Th-230,Ra-226 and Pb-210 are emitted at a
rate of2.22E-05,1.31E-05 and 7.88E-05 Ci/yr,respectively for Colorado Plateau ore.Similarly,
the decay daughters Th-230,Ra-226 and Pb-21O are emitted at a rate of5.67E-05,3.35E-05 and
2.01 E-04 Ci/yr,respectively for Arizona Strip ore.
Since the ore processing steps reject nearly all the radium to the tailings,very little radon is
released during the production of yellowcake.No significant radon releases occur during
yellowcake drying and packaging,since only about 0.1 %of the original Ra-226 in the ore is
found in yellowcake.Therefore,the amount of Rn-222 emitted from the yellowcake stack was
assumed to be negligible.
4.1.4 Vanadium Stack
The vanadium stack source term was only used in the MILDOS-AREA run for Colorado Plateau
ore.The vanadium present in the Colorado Plateau ore is partially solubilized during leaching.
The dissolved vanadium is present in uranium raffinate.Depending on its vanadium content,the
uranium raffinate will either be recyeled to the counter-current decantation step or further
processed for recovery of vanadium before recyeling.The product from the vanadium recovery
contains less than 0.005%U30 8 (NRC 1980).Therefore,the emission rate for the vanadium
stack was calculated to be 0.005%of the total emission rate from the yellowcake stacks (north
and south yellowcake stack)and U-238 was assumed to be emitted at a rate of 1.01E-06 Ci/yr.
Based on the EnecoTech (l99la and 1991b)measurements for the decay daughters of U-238
(Th-230,Ra-226 and Pb-21O)processed along with yellowcake of 0.22%,0.13%and 0.78%of
U-238,respectively,the emissions from the remaining radionuclides were assumed to be
negligible and in any event would likely be discharged to the tailings cells.
34489~IO·..FINAL -April 2008 4-4 SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4Bfor White Mesa Uranium Mill
4.2 AREA SOURCES
Mill area sources used in this assessment include the ore pads and the tailings cells.A
description ofthe approach used to calculate the emissions from area sources is provided in this
section.
4.2.1 Ore Pads
The ore pad storage operation has two different sources ofemissions,namely unloading ore from
trucks to the ore pad and wind emissions.Approximately 300,000 tons ofore were assumed to
be temporarily stockpiled at the mill's ore pads at any given time.Using a bulk ore density of
1.47 tons/yd3 (DUSA,Feb.6/07),the quantity of ore would create a pile 30 ft.(9.1 m)tall
covering approximately 4 acres (17,000 m2)stockpile area.
With respect to the truck unloading emissions,a process emission factor of 0.04 lbs of ore is
emitted per cubic yard handled (for a truck end and assuming no control (NRC 1987))and a bulk
ore density of 1.47 tons/yd3 was used in the calculations.With these assumptions,U-238 and its
decay daughters (assuming secular equilibrium)would be emitted at a rate of 1.58E-02 and
4.02E-02 Ci/yr for Colorado Plateau and Arizona Strip ore,respectively.
Wind erosion from the ore pad was assumed to have a 50%control factor due to the active
watering program in place (EnecoTech 1991a and 199Ib).This is conservative,in that actual
dust control on the ore pads may be better than this.The annual dust loss from the ore pad is
21.29 glm2yr;this was calculated using the method fi'om NRC Regulatory Guide 3.59 (NRC
1987)on the basis of the meteorological data (provided by DUSA (Turk 2007b))presented in
Appendix B;the annual dust loss from the ore pads is 10%that of the tailings piles since the
pmticulates in the ore pads are coarse material (I to 6 inch)because the ore has not yet been
ground.U-238 and its decay daughters (assuming secular equilibrium)were all assumed to be
emitted at a rate of 3.17E-04 and 8.07E-04 Ci/yr for Colorado Plateau and Arizona Strip ore,
respectively.Therefore,the total emission rate of U-238 and its daughter from truck dumping
and wind erosion is 1.61E-02 and 4.l0E-02 Ci/yr for Colorado Plateau and Arizona Strip ore,
respectively.
Rn-222 will be produced in the ore pads from the decay of Ra-226.The estimated annual radon
release rate from the ore pads is 375 and 956 Ci/yr for Colorado Plateau and Arizona Strip ore,
respectively.
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4.2.2 Tailings Cells
The characteristics of each tailings cell included in Phases 1 and 2 ofthe proposed development
ofnew tailings cell 4B are provided in Tables 4.2-1 and 4.2-2,respectively.
TABLE 4.2-1
CHARACTERISTICS OF TAILINGS CELLS IN PHASE I
Tailings Cell Interim Soil Cover (Inactive)Active
2 •0
3 0 •
4A 0 •
4B 0 0
TABLE 4.2-2
CHARACTERISTICS OF TAILINGS CELLS IN PHASE 2
Tailings Cell Interim Soil Cover (Inactive)Active
2 •0
3 •0
4A 0 •
4B 0 •
Active Tailings Cells
Wind erosion of tailings and radon release rates from the active tailings cell were estimated using
a maximal worst cast approach.However,since it is not possible to predict the distribution of
uncovered tailings between active cells at any given time,the active tailings cells were modelled
by using a maximal worst case approach.The following assumptions were used for the active
tailings cells:
•Each tailings cell was assumed to have a maximum area of 10 acres for uncovered
tailings material (this assumptions is considered to be conservative,because the average
area ofuncovered tailings in a cell is expected to be less than 10 acres).
•Wind-eroded tailings dust would arise from the 10 acres ofuncovered tailings.
•The total annual radon release rate for each tailings cell was calculated by assuming a
radon release rate of 20 pei/m2s (i.e.,maximum radon-222 emissions to ambient air from
an existing uranium mill pile that is allowed under the regulations)over the entire area of
each cell.However,this total annual radon release rate was assumed to be released from
the 10 acre area that was modelled.The area of tailings cell 3 was assumed to be 70
acres while tailing cells 4A and 4B were assumed to be 40 acres each.
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Using the onsite wind data generated over the last three years (provided by DUSA (Turk
2007b»,the annual dust loss fi'om the tailings cells was estimated to be approximately
213 g/m2yr;this was calculated using the method fi'om NRC Regulatory Guide 3.59 (NRC
1987).An average uranium recovery rate of 94%was assumed.In addition,a process emission
control factor of 70%was assumed,based on I)the active watering (tailings solutions spraying)
program on exposed areas of tailings beaches in active areas;2)solutions cover other tailings
areas;and 3)clUsting agents from the sprayed solutions act to minimize the erosion of the
tailings beaches by wind (EnecoTech 1991a and 199Ib).
With these assumptions and the particulate emission factor,U-238 would be emitted at a rate of
2.71 E-04 Ci/yr and the decay daughters Th-230,Ra-226 and Pb-21 0 would be emitted at a rate
of 4.52E-03 Ci/yr fi'om each active cell for Colorado Plateau are.These total annual emission
rates assume operation at the proposed are process rate of 730,000 tpy and an are specific
activity of 700 pCi/g.Similarly,for Arizona Strip ore,U-238 is emitted at a rate of 6.9IE-04
Ci/yr and the decay daughters Th-230,Ra-226 and Pb-21 0 are emitted at a rate of 1.15E-02 Ci/yr
fi'om each active cell.These total annual emission rates assume the proposed ore process rate of
730,000 tpy and an ore specific activity of 1783 pCi/g.
In this assessment,the total annual radon release rates for active tailings cell 3 and 4A and 48
were estimated to be 179 Ci/yr for tailings cell 3 and 102 Ci/yr for each of tailings cells 4A and
48.These estimates are extremely conservative because it was assumed that the radon release
rate of 20 pCi/m2s (i.e.,maximum radon-222 emissions to ambient air from an existing uranium
mill tailings impoundment)occurred over the entire area of each cell.Actual measurements
collected annually at the tailings cells to determine compliance with the NESHAPs radon
emanation standard have confinned that the 20 pCi/m2s release rate utilized for this assessment is
a conservative estimate.
Interim Soil Cover (Inactive Tailings Cells)
The tailings cells (2 and 3)with interim soil cover were assumed to be the entire areas of each
cell.The following assumptions were used for the tailings cells with interim soil covers:
•The area of tailings cell 2 with interim soil cover is 66.8 acres;
•The area of tailings cell 3 with interim soil cover is 70 acres;
• A nominal value of 10 pCi/m2s was used for radon flux based on historical values for the
Mill's tailings cells;and,
•No tailings dust will be released.
Using the assumptions above,the total annual radon release from the tailings cells 2 and 3 with
interim soil covers were 85.3 and 89.4 Ci/yr,respectively.
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4.3 METEOROLOGICAL DATA
Meteorological conditions influence re-suspension and dispersion of radionuclides from point
sources and area sources.The mill has an on-site weathering monitoring station that records
wind speed,wind direction and stability class.This data is used to formulate a joint frequency
distribution which is a required input for MlLDOS-AREA.The joint frequency distribution used
in this assessment was provided by DUSA (Turk 2007b)using the most recent three years (2004
to 2006)ofrecorded data.
4.4 POPULATION DATA
The population data was obtained from the year 2000 U.S.census and was used to complete
demographic and population dose projections.Census data is only available in 10 year intervals
for population centers of less than 65,000 residents,and local demographics have experienced
little change since the 2000 census.
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4.5 URANIUM MILL SOURCE EMISSION RATES
4.5.1 Colorado Plateau Ore
The calculated mill radioactive particulate and radon emission rates from point sources and area sources described in Sections 4.1 and
4.2,respectively for Colorado Plateau ore are provided in Table 4.5-1.
TABLE 4.5-1
RADIOACTIVE PARTICULATE AND RADON EMISSION RATES
(COLORADO PLATEAU ORE)
Ore Dump North YC South YC Interim Soil Cover Active VanadiumGrindingtoGrizzlyOrePadsStackStackTailingsTailingsTailingsTailingsTailingsStack'Cell 2 Cell 3 Cell 3 Ce1l4A Ce1l4B
U-238 9.27E-05 9.27E-05 L61E-02 LOIE-02 LOIE-02 O.OOE+OO O.OOE+OO 2.71E-04 2.7IE-04 2.71E-04 LOIE-06
Emission Th-230 9.27E-05 9.27E-05 L61E-02 2.22E-05 2.22E-05 O.OOE+OO O.OOE+OO 4.52E-03 4.52E-03 4.52E-03 2.22E-09
Rate Ra-226 9.27E-05 9.27E-05 L61E-02 l.31E-05 L31E-05 O.OOE+OO I O.OOE+OO 4.52E-03 4.52E-03 4.52E-03 l.31E-09
(Cilyr)Pb-210 9.27E-05 9.27E-05 L6IE-02 7.88E-05 7.88E-05 O.OOE+OO I O.OOE+OO 4.52E-03 4.52E-03 4.52E-03 7.88E-09
Rn-222 9.27E+Ol Note a 3.75E+02 Note a Note a 8.53E+Ol I 8.94E+OI L79E+02 L02E+02 L02E+02 Note a
Notes:
a)No significant release during this process.
b)Source is exclusive to the processing ofColorado Platean ore.
4.5.2 Arizona Strip Ore
The calculated mill radioactive particulate and radon emission rates from point sources and area sources described in Sections 4.1 and
4.2,respectively for Arizona Strip ore are provided in Table 4.5-2.
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TABLE 4.5-2
RADIOACTIVE PARTICULATE AND RADON EMISSION RATES
(ARIZONA STRIP ORE)
Ore Dump North YC South YC Interim Soil Cover Active
Griuding to Grizzly Ore Pads Stack Stack
Tailings Tailings Tailings Tailings Tailings
Cell 2 Cell3 Cell 3 CeIl4A CeIl4B
U-238 2.36E-04 2.36E-04 4.IOE-02 2.58E-02 2.58E-02 O.OOE+OO 0.00£+00 6.9 IE-04 6.91E-04 6.91E-04
Emission Th-230 2.36E-04 2.36E-04 4.1OE-02 5.67E-05 ,5.67E-05 O.OOE+OO 0.00£+00 1.15E-02 1.15E-02 1.15E-02
Rate Ra-226 2.36E-04 2.36E-04 4.IOE-02 3.35E-05 3.35E-05 O.OOE+OO O.OOE+OO 1.15E-02 1.15E-02 I 1.15E-02
(Cilyr)Pb-2IO 2.36E-04 2.36E-04 4.IOE-02 2.01E-04 2.01E-04 O.OOE+OO O.OOE+OO ,1.15E-02 1.15E-02 I 1.15E-02
Ro-222 2.36E+02 Note a 9.56E+02 Note a Note a .8.53E+OI 8.94£+01 1.79£+02 1.02E+02 I 1.02E+02
Note:
a)No significant release during this process.
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5.0 RECEPTORS
The receptors used in this assessment were provided by DUSA.The receptors used in this
assessment were as follows:
•Nearest Historical Resident (BHV-2);
•Nearest Actual Resident;
•Nearest Potential Resident (BHV-I);
•White Mesa Ute Community;
•Blanding,Utah.
In addition,two grazing locations I and 2 were considered as a possible source ofmeat.
As mentioned in Section 3.2,the receptor locations were detennined using GPS coordinates
provided by DUSA (Turk 2007a).The GPS coordinates were used for all the receptors except
for Grazing locations I and 2 where the easting and northing for Grazing locations I and 2 were
taken as nominal "mid-points"in Google Earth for these two receptor locations.
The receptor locations (plotted in Google Earth)with respect to the vanadium stack are shown in
Figure 5.1.
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FIGURE 5.1
RECEPTOR LOCAnONS
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At the time of the 1979 Final Environmental Statement (FES)(NRC 1979)for the mill,the
nearest resident lived approximately 4.8 miles (4.5)km north-north east of the mill building,near
the location of air monitoring station BHV-2 (also referred to as the historical nearest resident.)
Currently,the nearest "potential"resident is approximately 1.2 miles (1.9 km)north ofthe Mill,
near the location of air monitoring station BHV-I.The nearest actual resident is located
approximately 1.6 miles (2.5 km)north of the mill.Nearby population h'TOUPS include the
community of White Mesa,about 8.5 km south east and the city of Blanding,approximately
6 miles (10 km)from the mill.
The area to the immediate north of the mill (Grazing location I)is believed to be used only for
grazing of meat animals (beef)(NRC 1979).A second location (Grazing location 2)to the east
and south of the mill is also used for the grazing of meat animals (beef)as was assumed in the
EnecoTech analysis (EnecoTech 1991a and 199Ib).Although considered unlikely,in one worst
case scenario,it is possible that the meat animals grazed at Grazing location I and 2 would be
eaten by the residents near the mill.A scenario which suppolls dairy cattle grazing at Grazing
locations I and 2 was not included because the prospect of suppolling dairy cattle in those
locations is not credible,given the arid climate and the much larger feed requirements of dairy
cattle as opposed to beefcattle.DUSA has also indicated that there are no dairy cattle grazed in
Grazing locations I and 2.It should be noted,however,that in all of the MILDOS-AREA model
runs in this report,it was assumed,conservatively,that individuals at each receptor location
drink all of their milk from cows and eat all of their beef from cattle that graze at the receptor
locations (but not at Grazing locations I or 2).This is thought to be a very conservative
assumption.
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6.0 RADIATION DOSE ESTIMATES
This section describes the MILDOS-AREA results ofthe mill's potential radiological impacts on
the population in the vicinity of the Mill.This analysis was primarily based on the estimated
annual releases of radioactive materials and assumptions discussed in Sections 4.0 and 5.0.All
potential exposure pathways which are likely to impact individuals near the mill were included in
the MILDOS-AREA model.
MILDOS-AREA calculates the total annual effective dose commitment (including radon).The
calculated total annual effective dose commitments were compared to the 10 CFR 20 (R3 13-I5)
requiremcnts that the dose to individual mcmbcrs of the public shall not exceed 100 mrcm/yr
(radon ineluded).In addition,MILDOS-AREA calculates 40 CFR 190 doses (excludes radon).
The 40 CFR 190 Criterion is 25 mrem/yr to thc whole body (excluding the dose duc to radon)
and 25 mrem/yr to any othcr organ to any member of the public (EPA 2002).The 40 CFR 190
doses were also used to demonstrate compliance with 10 CFR 20.1 101(d)(R313-15-101(4».
Under 10 CFR 20.1 101(d)(R313-15-IOI(4)the licensee must demonstrate as an ALARA goal
that the total effective dose equivalcnt to the individual member of the public likely to receive
thc highest total effectivc dose cquivalent will not exceed 10 mrem/yr (absent ofthe radon dose).
In this assessment,a worst-case scenario in which there is a possibility that individuals near the
mill ingcst meat from cattle grown at Grazing Location 1 or 2 was considered.It was assumed
that thc cattle will graze at Grazing location 1 or 2 for two months of the year (due to the arid
nature of the rcgion and the lack of forage).Therefore,the meat ingestion dose to individuals
near the mill who might consumc beefi,rrazed at Grazing Location I or 2 was assumed to be onc-
sixth of the MILDOS-AREA calculated meat ingestion dose from these grazing locations.
As mentioned in Section 1.3,MILDOS-AREA was run separately for Colorado Plateau and
Arizona Strip ore.Total annual dose commitments and 40 CFR 190 annual dosc commitments
were estimated for locations in which individual members of the public might reside (Nearest
Potential Resident (BHV-I),Nearest Historical Resident (BHV-2),Nearest Actual Resident,
White Mesa Ute Community and Blanding,Utah)for two development Phases of the new
tailings cells.The total annual dose commitments and 40 CFR 190 annual dose commitments for
Phases 1 and 2 are provided in Sections 6.1 and 6.2 for Colorado Platcau and Arizona Strip ore,
respectively.In addition,total annual dose commitments and 40 CFR 190 annual dose
commitments from the meat ingestion pathway that is estimated for Grazing location 1 and 2 are
provided in Sections 6.1 and 6.2,respectively.
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6.1 MILDOS-AREA RESULTS FOR COLORADO PLATEAU ORE
The potential annual doses to the people living close to the mill and to the population living
within 50 miles (80 km)as a result of processing Colorado Plateau ore was calculated using
MILDOS-AREA.
The MILDOS-AREA-calculated total annual dose commitments (including radon)and 40 CFR
190 total annual dose commitment for processing of Colorado Plateau ore are provided in
Sections 6.1.1 and 6.1.2,respectively
6.1.1 R313-15-301(1)(a)Regulatory Compliance
The MILDOS-AREA calculated total annual dose commitments (including radon)for Phases I
and 2 are provided in this section.These doses are regulated by R313-15-30I(l)(a)which
requires that the dose to an individual member of the public shall not exceed 100 mrem/yr (radon
included).
Phase 1
Table 6.1-1 presents a summary of the individual dose commitments for the residential receptors
for the age group of infant,child,teenage and adult for Phase 1.
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TABLE 6.1-1
PHASE I-COMPARISON OF ANNUAL DOSE COMMITMENTS TO APPLICABLE
RADIATION PROTECTION STANDARDS (COLORADO PLATEAU ORE)
Location Age Organ Estimated Dose Applicable Limit Fraction
Groun (mrelll/vr)'(mrem/vr)ofLimit
Infant Effective 1.37E+00 100 1.37E-02
Bone 1.92E+00 --
Avg.Lung 5.3IE-Ol --
Bronchi 1.30E+OI --
Child Effective 1.05E+00 100 1.05E-02-Bone 1.37E+00 --
Avg.Lung 7.lOE-OI --
Nearest Potential Bronchi 1.30E+Ol --
Resident (BHV-I)Teenage Effective 1.I0E+00 100 1.I0E-02-
Bone 4.84E+00 --
Avg.Lung 5.68E-OI ----Bronchi 1.30E+Ol --
Adult Effective 9.84E-OI 100 9.84E-03
Bone 2.13E+OO --
Avg.Lung 3.97E-OI --
Bronchi 1.30E+OI --
Infant Effective 3.lOE-Ol 100 3.10E-03
Bone 3.05E-Ol --
Avg.Lung 1.06E-Ol --
Bronchi 3.52E+00 --
Child Effective 2.66E-OI 100 2.66E-03
Bone 2.33E-OI ---
Avg.Lung 1.29E-OI --
Nearest Historical Bronchi 3.52E+00 --
Resident (BHV-2)Teenage Effective 2.72E-Ol 100 2.72E-03---
Bone 7.63E-Ol ---
Avg.Lung 1.05E-Ol --
Bronchi 3.52E+00 --
Adult Effective 2.55E-Ol 100 2.55E-03
Bone 3.53E-01 --
Avg.Lung 7.69E-02 --
Bronchi 3.52E+00 ---
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TABLE 6.1-1 (Coot'd)
PHASE I-COMPARISON OF ANNUAL DOSE COMMITMENTS TO APPLICABLE
RADIATION PROTECTION STANDARDS (COLORADO PLATEAU ORE)
Location Agc Organ Estimated Dose Applicable Limit Fraction
Groun Imrem/yr)-Imrem/vr)ofLimit
Infant Effective 8.78E-OI 100 8.78E-03
Bone 1.13E+00 --
Avg.Lung 3.17E-OI --
Bronchi 8.78E+00 --
Child Effective 6.95E-OI 100 6.95E-03_..
Bone 8.12E-OI --
Avg.Lung 4.2IE-OI --
Nearest Actual Bronchi 8.78E+00 --
Resident Teenage Effective 7.2IE-OI 100 7.2 IE-03
Bone 2.83E+00 --
Avg.Lung 3.39E-OI --
Bronchi 8.78E+00 --
Adult Effective 6.55E-OI 100 6.55E-03
Bone 1.26E+00 --
Avg.Lung 2.40E-OI --
Bronchi 8.78E+00 --
Infant Effective 2.45E-OI 100 2.45E-03
Bone 1.45E-OI --
Avg.Lung 6.72E-02 --
Bronchi 3.18E+00 --
Child Effective 2.25E-OI 100 2.25E-03
Bone 1.08E-OI --
Avg.Lung 6.47E-02 --
White Mesa Bronchi 3.18E+00 --
Community Teenage Effective 2.26E-0I 100 2.26E-03
Bone 2.86E-OI --
Avg.Lung 5.26E-02 --
Bronchi 3.18E+00 --
Adult Effective 2.20E-OI 100 2.20E-03
Bone 1.48E-OI --
Avg.Lung 4.27E-02 --
Bronchi 3.18E+00 --
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TABLE 6.1-1 (Cont'd)
PHASE I-COMPARISON OF ANNUAL DOSE COMMITMENTS TO APPLICABLE
RADIATION PROTECTION STANDARDS (COLORADO PLATEAU ORE)
Location Age Organ Estimated Dose Applieable Limit Fraction
Group (mrem/vr\(mrem/vr)ofLimit
Infant Effective 1.07E-OI 100 1.07E-03
Bone 8.94E-02 --
Avg.Lung 3.36E-02 --._-
Bronchi l.25E+00 --
Child Effective 9.38E-02 100 9.38E-04
Bone 6.78E-02 --
Avg.Lung 3.91E-02 --
Blanding Bronchi l.25E+00 --1------EffectiveTeenage 9.55E-02 100 9.55E-04
Bone 2.10E-Ol --
Avg.Lung 3.23E-02 --
Bronchi 1.25E+00 --
Adult Effective 9.08E-02 100 9.08E-04---
Bone 1.00E-01 --
Avg.Lung 2.47E-02 --
Bronchi 1.25E+00 --
From Table 6.1-1,the total annual effective dose commitments are at most 1.4%(effective dose
for infant at SHY-I)of the R313-15-30I(l)(a)limit of 100 mrem/yr (radon included)to an
individual member of the public.Therefore,the predicted annual effective dose commitments
comply with R313-15-30I(l)(a).
In the worst case scenario in which there is a possibility that individuals near the mill ingest meat
fi-om cattle grown at Grazing Location I or 2.It was assumed that the cattle will graze at
Grazing location I or 2 for 2 months of the year.The meat ingestion dose to individuals near the
mill who might consume beefgrazed at Grazing Location I or 2 was assumed to be one-sixth of
the MILDOS-AREA calculated meat ingestion dose from these grazing locations.Table 6.1-2
presents a summary of the annual dose commitments from the meat ingestion pathway for
Grazing location I and 2.Even in the very unlikely event that a resident were to consume meat
fi'om one ofthe grazing locations,the total dose would remain well below regulatory limits.
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TABLE 6.1-2
PHASE I-TOTAL ANNUAL DOSE COMMITMENTS FOR MEAT INGESTION
PATHWAY (COLORADO PLATEAU ORE)(mrem/yr)
Location Age Organh
Gronp Effective'Bonea Avg.Lnng'
Infant O.OOE+OO O.OOE+OO O.OOE+OO
Grazing Location I Child 1.08E-02 5.40E-02 4.91E-02-
Teenage 1.70E-02 2.80E-OI 4.30E-02
Adult 1.23E-02 1.52E-0 I 3.55E-02
Infant O.OOHOO O.OOE+OO O.OOE+OO
Grazing Location 2 Child 7.35E-04 3.65E-03 3.12E-03
Teenage 1.14E-03 1.92E-02 2.72E-03
Adult 8.13E-04 1.01E-02 2.25E-03
Note:
a)Assumes cattle will graze at the particular Grazing location for 2 months ofthe year.
Phase 2
Table 6.1-3 presents a summary ofthe individual dose commitments for the residential receptors
for the age group ofinfant,child,teenage and adult for Phase 2.
TABLE 6.1-3
PHASE 2-COMPARISON OF ANNUAL DOSE COMMITMENTS TO APPLICABLE
RADIATION PROTECTION STANDARDS (COLORADO PLATEAU ORE)
Location Agc Organ Estimated Dose Applicable Limit Fraction
Gronp (mrem/yr)(mrem/yr)ofLimit
Infant Effective l.35E+00 100 1.35E-02
Bone 1.90E+00 --
Avg.Lung 5.20E-OI --..._-
Bronchi 1.28E+OI --
Child Effective 1.04E+00 100 1.04E-02
Bone l.35E+00 --
Avg.Lung 6.93E-OI --
Ncarcst Potential Bronchi 1.28HOJ --
Resident (BHV-I)Teenage Effective 1.08E+00 100 1.08E-02
Bone 4.75E+00 --
Avg.Lung 5.54E-0I --
Bronchi 1.28E+OI --
Adult Effective 9.68E-OJ 100 9.68E-03
Bone 2.09E+00 --
Avg.Lung 3.87E-OJ --
Bronchi 1.28E+OJ --
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TABLE 6.1-3 (Cont'd)
PHASE 2-COMPARlSON OF ANNUAL DOSE COMMITMENTS TO APPLICABLE
RADIATION PROTECTION STANDARDS (COLORADO PLATEAU ORE)
Location Age Organ Estimated Dose Applicable Limit Fraction
Gronn (mrem/yr)(mrem/yr)ofLimit
Infant Effective 3.IOE-OI 100 3.lOE-03-
Bone 3.03E-OI --
Avg.Lung 1.05E-OI ---
Bronchi 3.52E+00 --_.
Child Effective 2.66E-0 I 100 2.66E-03
Bone 2.3IE-OI --
Avg.Lung 1.28E-OI --.-
Nearest Historical Bronchi 3.52E+00 --
Resident (BHV-2)Teenage Effective 2.72E-OI 100 2.72E-03
Bone 7.57E-0 I --
Avg.Lung 1.04E-OI --
Bronchi 3.52E+00 --
Adult Effective 2.55E-OI 100 2.55E-03
Bone 3.50E-OI --
Avg.Lung 7.63E-02 --
Bronchi 3.52E+00 --
Infant Effective 8.70E-OI 100 8.70E-03
Bone 1.12E+00 --
Avg.Lung 3.IIE-OI ---
Bronchi 8.69E+00 --
Child Effective 6.88E-OJ 100 6.88E-03
Bone 7.98E-OI --
Avg.Lung 4.J3E-OI --
Nearest Actual Bronchi 8.69E+00 --
Resident -Teenage Effective 7.13E-OI 100 7.13E-03
--Bone 2.78E+00 --
Avg.Lung 3.32E-OI --
Bronchi 8.69E+00 --
Adult Effective 6048E-01 100 6048E-03
Bone 1.23E+00 --
--Avg.Lung 2.35E-OI --
Bronchi 8.69E+00 --
34489-10 ...FINAL -April 2008 6-7 SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4B for White Mesa Uranium Mill
TABLE 6.1-3 (Cont'd)
PHASE 2-COMPARIS0N OF ANNUAL DOSE COMMITMENTS TO APPLICABLE
RADIATION PROTECTION STANDARDS (COLORADO PLATEAU ORE)
Location Age Organ Estimated Dose Applicable Limit Fraction
Grolln (mrem/vr)(mrem/vr)of Limit
Infant Effective 2.47E-01 100 2.47E-03
Bone 1.45E-01 --
Avg.Lung 6.69E-02 --
Bronchi 3.20E+00 --
Child Effective 2.26E-01 100 2.26E-03
Bone 1.07E-01 ---Avg.Lung 6.45E-02 --
White Mesa Bronchi 3.20E+00 --
Community Teenage Effective 2.28E-01 100 228E-03'--
Bone 2.85E-OI ---
Avg.Lung 5.25E-02 --
Bronchi 3.20E+00 --
Adult Effective 2.22E-01 100 2.22E-03
Bone 1.48E-01 --
Avg.Lung 4.27E-02 --
Bronchi 3.20E+00 --
Infant Effective 1.08E-01 100 1.08E-03
Bone 8.94E-02 --
Avg.Lung 3.36E-02 ------
Bronchi l.26E+00 ---Child Effective 9.46E-02 100 9,46E-04--
Bone 6.79E-02 --._-
Avg.Lung 3.92E-02 --
Blanding Bronchi 1.26E+00 --
Teenage Effective 9.62E-02 100 9.62E-04---Bone 2.10E-01 --.__.
Avg.Lung 3.23E-02 -----Bronchi 1.26E+00 --
Adult Effective 9.15E-02 100 9.15E-04
Bone 1.00E-01 --
Avg.Lung 2.48E-02 --f---.
Bronchi l.26E+00 --
From Table 6.1-3,the total annual effective dose commitments are at most 1.4%(effective dose
for infant at BHV-I)of the R313-15-30I(l)(a)limit of 100 mrem/yr (radon included)to an
individual member of the public.Therefore,the predicted annual effective dose commitments
comply with R313-15-301 (l)(a).
In addition,Table 6.1-4 presents a summary of the annual dose commitments from the meat
ingestion pathway for Grazing location I and 2.As before,in the very unlikely event that a
34489-10 -FINAL -April 2008 6-8 SENES Consultants Limited
Proposed Development ofNew Tailings Ce1l4B for White Mesa Uranium Mill
resident were to consume meat from one of the grazing locations,the total do se would remain
well below regulatory limits.
TABLE 6.1-4
PHASE 2-TOTAL ANNUAL DOSE COMMITMENTS FOR MEAT INGESTION
PATHWAY (COLORADO PLATEAU ORE)(mremlyr)
Location Age Organ"
Group Effectivea Ronca Avg.Lung'
Infant O.OOE+OO O.OOE+OO O.OOE+OO ..-
Grazing Location 1 Child l.07E-02 5.35E-02 4.87E-02
Teenage 1.68E-02 2.78E·Ol 4.26E-02
Adult 1.22E-02 1.50E-Ol 3.5IE-02}----...
O.OOHOOInfant O.OOE+OO O.OOHOO
Grazing Location 2 Child 6.73E-04 3.34E-03 2.82E-03
Teenage l.04E-03 1.76E-02 2.46E-03
Adult 7.4 IE-04 9.22E-03 2.03E-03
Note:
a)Assumes cattle will graze at the particular Grazing location for 2 months ofthe year.
6.1.2 40 CFR 190 Regulatory Compliance
MILDOS-AREA calculated 40 CFR 190 doses (excludes radon).These doses are regulated by
the 40 CFR 190 criterion of 25 mrem/yr to the whole body (excluding the dose due to radon)
(EPA 2002)or to any organ of the body.The 40 CFR 190 doses are also used to demonstrate
compliance with R313-15-IOI(4)(10 CFR 20.1101(d)).The licensee must demonstrate as an
ALARA goal,that total effective dose equivalent to the individual member ofthe public likely to
receive the highest total effective dose equivalent will not exceed 10 mrem/yr (absent of the
radon dose).
Phase 1
Table 6.1-5 presents a summary of the 40 CFR 190 individual dose commitments for residential
receptors for the age group ofinfant,child,teenage and adult for Phase 1.
34489·10 -FINAL·April 2008 6-9 SENES Consultants Limited
____P'--ro2,'P_o-'-se.d Development ofNew Tailings Cell4Bfor White Mesa Uranium Mill
TABLE 6.1-5
PHASE I-COMPARISON OF 40 CFR 190 ANNUAL DOSE COMMITMENTS WITH
APPLICABLE RADIATION PROTECTION STANDARDS
(COLORADO PLATEAU ORE)
Location Age Organ Estimated Dose Applicable Limit Fraction of
Group (mrem/yr) (mrem/yr)Limitf--
Iufant Effective 5,45E-Ol 25 2.18E-02
Bone l.86E+OO 25 7,45E-02._-
--Avg.Lung 4.85E-Ol 25 l.94E-02
Bronchi 9.73E-04 no limit given -
Child Effective 2.32E-Ol 25 9.28E-03
Bone 1.33E+OO 25 5.30E-02
Avg,Lung 6.62E-Ol 25 2.65E-02
Nearest Potential Bronchi 9.73E-04 no limit given -
Resident (BHV-1)---
Teenage Effective 2.76E-Ol 25 1.l0E-02
Bone 4.79E+OO 25 l.92E-OI
Avg.Lung 5.22E-Ol 25 2.09E-02
Bronchi 9.73E-04 no limit given -
Adult Effective l.63E-Ol 25 6.50E-03
Bone 2.09E+OO 25 8.35E-02
Avg.Lung 3.5IE-OI 25 l.40E-02
Bronchi 9.73E-04 no limit given -
Infant Effective 8.07E-02 25 3.23E-03
Bone 2.82E-Ol 25 1.l3E-02
Avg.Lung 8.56E-02 25 3,42E-03
Bronchi 1.39E-04 no limit given -
Child Effective 3.6IE-02 25 1,44E-03
Bone 2.09E-Ol 25 8.37E-03
Avg.Lung l.07E-Ol 25 4.29E-03--
Nearest Historical Bronchi 1.39E-04 no limit given -
Resident (BHV-2)--
Teenage Effective 4.26E-02 25 l.71E-03
Bone 7.30E-Ol 25 2.92E-02
Avg.Lung 8.31E-02 25 3.32E-03
Bronchi 1.39E-04 no limit given -
Adult Effective 2.55E-02 25 l.02E-03
Bone 3.26E-Ol 25 l.30E-02
Avg.Lung 5.62E-02 25 2.25E-03
Bronchi 1.39E-04 no limit given -
34489-10 -FINAl.-April 2008 6-10 SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4Bfor White Mesa Uranium Mill
TABLE 6.1-5 (Cont'd)
PHASE I-COMPARISON OF 40 CFR 190 ANNUAL DOSE COMMITMENTS WITH
APPLICABLE RADIATION PROTECTION STANDARDS
(COLORADO PLATEAU ORE)
Location Age Organ Estimated Dose Applicable Limit Fraction of
Group (mrem/yr)(mrem/yrj Limit
Infant Effective 3.I7E-OI 25 I.27E-02
-_._._---_.-Bone I.09E+OO 25 4.37E-02
Avg.Lung 2.8IE-OI 25 !.l2E-02 -_.
Bronchi 5.62E-04 no limit given -
Child Effective 1.35E-OI 25 5.40E-03
Bone 7.73E-OI 25 3.09E-02-
Avg.Lung 3.84E-OI 25 I.54E-02------_.__.._..._.
Nearest Actual Resident Bronchi 5.62E-04 no limit given -
Teenage Effective I.60E-OI 25 6.42E-03
Bone 2.78E+OO 25 !.lIE-OI
Avg.Lung 3.02E-OI 25 I.2IE-02
Bronchi 5.62E-04 no limit given -
Adult Effective 9.46E-02 25 3.78E-03
Bone I.2IE+OO 25 4.86E-02
Avg.Lung 2.03E-OI 25 8.12E-03
Bronchi 5.62E-04 no limit given -
Infant Effective 3.36E-02 25 1.35E-03-
Bone !.l9E-OI 25 4.74E-03
Avg.Lung 4.55E-02 25 I.82E-03.-
Bronchi 4.25E-05 no limit given -
Child Effective 1.3 IE-02 25 5.22E-04
----Bone 7.80E-02 25 3.12E-03
Avg.Lung 3.85E-02 25 I.54E-03
White Mesa Community Bronchi 4.25E-05 no limit given -
Teenage Effective 1.38E-02 25 5.5IE-04
Bone 2.3IE-OI 25 9.26E-03
1---._--_._--Avg.Lung 2.72E-02 25 I.09E-03
Bronchi 4.25E-05 no limit given -
Adult Effective 8.69E-03 25 3.48E-04
Bone !.lIE-OI 25 4.42E-03
Avg.Lung I.9IE-02 25 7.63E-04
Bronchi 4.25E-05 no limit given -
34489-10 -FINAL -April 2008 6-11 SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4B for White Mesa Uranium Mill
TABLE 6.1-5 (Cont'd)
PHASE I-COMPARISON OF 40 CFR 190 ANNUAL DOSE COMMITMENTS WITH
APPLICABLE RADIATION PROTECTION STANDARDS
(COLORADO PLATEAU ORE)
Location Age Organ Estimated Dose Applicable Limit Fraction of
Groll»(mrem/vr)Imrem/vr)Limit
Infant Effective 2.21E-02 25 8.84E-04
Bone 7.69E-02 25 3.08E-03
Avg.Lung 2.39E-02 25 9.57E-04-
Bronchi 3,49E-05 no limit given -
Child Effective 9.23E-03 25 3.69E-04
Bone 5.38E-02 25 2.15E-03
Avg.Lung 2.69E-02 25 l.08E-03
Blanding Bronchi 3.49E-05 no limit given -
Teenage Effective l.06E-02 25 4.24E-04
f----------Bone l.81E-Ol 25 7.25E-03
Aw.Lung 2.05E-02 25 8.19E-04
Bronchi 3,49E-05 no limit given -
Adult Effective 6.38E-03 25 2.55E-04
Bone 8.16E-02 25 3.27E-03
Avg.Lung l.39E-02 25 5.57E-04
Bronchi 3.49E-05 no limit given -
From Table 6.1-5,the 40 CFR 190 annual dose commitments are at most 19.2%(dose to the
bone for the teenage at SHV-I)ofthe 40 CFR 190 dose criterion of25 mrem/yr.In addition,the
40 CFR 190 annual effective dose commitments demonstrate compliance with the R313-15-
101(4)(10 CFR 20.1101(d»ALARA goal of 10 mrem/yr to the individual member of the public
likely to receive the highest total effective dose equivalent.The maximum total effective dose
equivalent was 0.545 mrem/yr (infant at SHV-I),or 5.45%of the 10 mrem/yr goal.
In addition,Table 6.1-6 presents a summary of the 40 CFR 190 annual dose commitments from
the meat ingestion pathway for Grazing Locations I and 2.As before,in the unlikely event a
receptor were to eat meat from cattle grazing in areas I or 2,the total dose would remain well
below regulatory limits.
34489-10 -FINAL-April 2008 6-12 SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4Bfor White Mesa Uranium Mill
TABLE 6.1-6
40 CFR 190 ANNUAL DOSE COMMITMENTS FOR MEAT INGESTION PATHWAY
(COLORADO PLATEAU ORE)(mremlyr)
Location Age Group Or~anb
Effeetive'Bonca Avg.Lung'
Infant O.OOE+OO O.OOE+OO O.OOE+OO
Grazing Location I Child 1.08E-02 5.40E-02 4.9IE-02
Teenage l.70E-02 2.80E-OI 4.30E-02
Adult 1.23E-02 1.52E-0 I 3.55E-02
Infant O.OOE+OO O.OOE+OO O.OOE+OO
Grazing Location 2 Child 7.33E-04 3.63E-03 3.IOE-03
Teenage 1.13E-03 1.91E-02 2.72E-03
Adult 8.IOE-04 1.01 E-02 __2.24E-03
Note:
a)Assumes cattle will graze at the particular Grazing location for 2 months ofthe year.
b)Exclusive ofradon.
The annual doses to the population estimated within 50 miles (80 km)of the site are provided in
Table 6.1-7.
TABLE 6.1-7
PHASE I-ANNUAL POPULATION DOSE COMMITMENTS WITHIN SO MILES
(80 km)OF THE MILL FOR COLORADO PLATEAU ORE
ANNUAL POPULATION DOSE COMMITMENTS,
Organ PERSON-REM PER YEAR
Mill Operations
Effective 1.47E-OI
Bone 1.12E+00
Avg.Lung 1.53E-OI
Bronchi 8.60E+00
The population dose arising from processing Colorado Plateau ore during Phase 1 is estimated at
0.15 person-rem.This can be compared to the dose from natural background sources of
radiation.
In the United States,nominal average levels of natural background radiation are as follows
(NCR?1987):
Cosmic and Cosmogenic
Terrestrial
Inhaled (Radon)
Ingested
Total (Average)
28 mrem/yr
28 mrcm/yr
200mrem/yr
40 mrem/yr
296 mrern/yr (96 mremlyr excluding radon)
34489-10-FINAL -April 2008 6-13 SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4Bfor White Mesa Uranium Mill
In the area of the White Mesa Mill,natural background radiation was measured at two sites in
1977:the project site (Blanding)and the Hanksville site.At the Blanding site,the average dose
equivalent from external radiation was about 142 mrem/yr.Of this 142 mrem/yr,68 mrem/yr
came from cosmic radiation,while 74 mrem/yr came fi'om telTestrial radiation.
(Dames &Moore 1978).At the Hanksville site,the corresponding average dose equivalent was
about 122 mrem/yr (68 mrem/yr fi'om cosmic radiation and 54 mrem/yr from telTestrial
radiation).(Dames &Moore 1978).
Ingested radionuclides would contribute (about)a further 18 mrem/yr (NRC 1979).This brings
the total background dose from external radiation and ingested radioactivity,but exclusive ofthe
dose from radon-222,to about 161 mrem/yr;which is higher than both the U.S.averages of
96 mrem/yr.
If the nominal U.S.dose fi'om radon of about 200 mrem per year is added,then the total dose
from natural background in the area ofthe mill is 360 mrem/yr (or more assuming the dose from
radon would increase along with that from telTestrial source).
The cun'ent population ofSan Juan County is about 14,400 people.Assuming everyone living in
San Juan County receives an annual dose of (about)360 mrem/yr,then the total dose due to
natural background is approximately 5184 person-rem.The theoretical incremental dose of
0.15 person-rem is clearly inconsequential by comparison.
Phase 2
Table 6.1-8 presents a summary of the 40 CFR 190 individual dose commitments for the
residential receptors for the age group ofinfant,child,teenage and adult for Phase 2.
34489-10 --FINAL -April 2008 6-14 SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4B for White Mesa Uranium Mill
TABLE 6.1-8
PHASE 2-COMPARISON OF 40 CFR 190 ANNUAL DOSE COMMITMENTS WITH
APPLICABLE RADIATION PROTECTION STANDARDS
(COLORADO PLATEAU ORE)
Location Age Organ Estimated Dose Applicable Limit Fraction of
GrouD (mrem/vr)(mrem/m Limit
Infant Effective 5.40E-OI 25 2.16E-02
Bone 1.84E+00 25 7.36E-02
Avg.Lung 4.75E-Ol 25 1.90E-02
Bronchi 9.63E-04 no limit given -
Child Effective 2.28E-01 25 9.11E-03
Bone 1.30E+00 25 5.20E-02
Avg.Lung 6.46E-01 25 2.58E-02
Nearest Potential Bronchi 9.63E-04 no limit given -
Resident (BHV-1)-
Teenage Effective 2.70E-Ol 25 1.08E-02
Bone 4.70E+00 25 1.88E-Ol
Avg.Lung 5.09E-Ol 25 2.03E-02
Bronchi 9.63E-04 no limit given -
Adult Effective 1.59E-Ol 25 6.36E-03
Bone 2.04E+00 25 8.17E-02
Avg.Lung 3.42E-01 25 1.37E-02
Bronchi 9.63E-04 no limit given -
Infant Effective 8.03E-02 25 3.21E-03
Bone 2.81E-Ol 25 1.I2E-02
Avg.Lung 8.47E-02 25 3.39E-03
Bronchi 1.38E-04 no limit given -
Child Effective 3.58E-02 25 1.43E-03
Bone 2.07E-Ol 25 8.29E-03--
Avg.Lung 1.06E-Ol 25 4.24E-03
Nearest Historical Bronchi 1.38E-04 no limit given -
Resident (BHV-2)Teenage Effective 4.22E-02 25 1.69E-03
Bone 7.23E-Ol 25 2.89E-02
Avg.Lung 8.21E-02 25 3.29E-03--
Bronchi 1.38E-04 no limit given -
Adult Effective 2.53E-02 25 1.01E-03
Bone 3.23E-Ol 25 1.29E-02
Avg.Lung 5.56E-02 25 2.22E-03
Bronchi 1.38E-04 no limit given -
34489-10 ...FINAL -April 2008 6-15 SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4B for White Mesa Uranium Mill
TABLE 6.1-8 (Cont'd)
PHASE 2-COMPARISON OF 40 CFR 190 ANNUAL DOSE COMMITMENTS WITH
APPLICABLE RADIATION PROTECTION STANDARDS
(COLORADO PLATEAU ORE)
Location Age Organ Estimated Dose Applicable Limit Fraction of
Group (mrem/vr\(mrem/vr)Limit
Infant Effective 3.l5E-Ol 25 1.26E-02
Bone 1.08E+OO 25 4.32E-02
Avg.Lung 2.75E-Ol 25 1.10E-02
Bronchi 5.57E-04 no limit given -
Child Effective 1.33E-Ol 25 5.31E-03
Bone 7.59E-Ol 25 3.04E-02
Avrr.Lnnrr 3.76E-Ol 25 1.50E-02._...
Nearest Actual Resident Bronchi 5.57E-04 no limit given -
Teenage Effective 1.58E-OI 25 6.30E-03
Bone 2.73E+OO 25 1.09E-Ol
Avg.Lunrr 2.95E-OI 25 1.18E-02
Bronchi 5.57E-04 no limit given -
Adult Effective 9.28E-02 25 3.7IE-03
Bone 1.19E+OO 25 4.77E-02
Avg.Lung 1.99E-OI 25 7.94E-03
Bronchi 5.57E-04 no limit given -
Infant Effective 3.35E-02 25 1.34E-03
Bone 1.18E-Ol 25 4.71E-03
Avg.Lung 4.50E-02 25 1.80E-03
Bronchi 4.23E-05 no limit given -
Child Effective 1.29E-02 25 5.l7E-04
Bone 7.72E-02 25 3.09E-03
Avg.Lung 3.80E-02 25 1.52E-03
White Mesa Community Bronchi 4.23E-05 no limit given -
Teenage Effective 1.36E-02 25 5.46E-04
Bone 2.29E-O I 25 9.17E-03
Avg.Lunrr 2.69E-02 25 1.08E-03
Bronchi 4.23E-05 no limit given -
Adult Effective 8.60E-03 25 3.44E-04
Bone 1.09E-Ol 25 4.37E-03-
Avrr.Lung 1.88E-02 25 7.54E-04
Bronchi 4.23E-05 no limit given -
34489-10 ..-FINAL -April 2008 6-16 SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4Bfor White Mesa Uranium Mill
TABLE 6.1-8 (Cont'd)
PHASE 2-COMPARISON OF 40 CFR 190 ANNUAL DOSE COMMITMENTS WITH
APPLICABLE RADIATION PROTECTION STANDARDS
(COLORADO PLATEAU ORE)
Location Age Organ Estimated Dose Applicable Limit Fraction of
GrouD (mrem!vr)_(mr".,!,{~Limit
Infant Effective 2.2IE-02 25 8.83E-04
Bone 7.69E-02 25 3.07E-03---_._--
Avg.Lung 2.39E-02 25 9.55E-04
Bronchi 3.49E-05 no limit given -
Child Effective 9.22E-03 25 3.69E-04
Bone 5.37E-02 25 2.15E-03
Avg.Lung 2.68E-02 25 l.07E-03
Blanding Bronchi 3.49E-05 no limit given -
Teenage Effective l.06E-02 25 4.23E-04
Bone 1.8IE-OI 25 7.24E-03
Avt!.LUI1rr 2.04E-02 25 8.18E-04
Bronchi 3.49E-05 no limit given -
Adult Effective 6.37E-03 25 2.55E-04
Bone 8.15E-02 25 3.26E-03
Avg.Lnng 1.39E-02 25 5.56E-04
Bronchi 3.49E-05 no limit given -
From Table 6.1-8,the 40 CFR 190 annual dose commitments are at most 18.8%(dosc to the
bone for the teenage at BHV-1)ofthe 40 CFR 190 dose criterion of25 mrem/yr.In addition,the
40 CFR 190 annual effective dose commitments demonstrate compliance with the R313-15-
101(4)(10 CFR 20.1101(d))ALARA goal of 10 mrem/yr to the individual member of the public
likely to receive the highest total effective dose equivalent.The maximum total effective dose
equivalent was 0.540 mrem/yr (infant at BHV-l),or 5.4%of the 10 mrem/yr goal.
In addition,Table 6.1-9 presents a summary of the 40 CFR 190 annual dose commitments from
the meat ingestion pathway for Grazing Locations 1 and 2.As before,in the unlikely event a
receptor were to eat meat from cattle grazing in areas I or 2,the total dose would remain well
below regulatory limits.
34489-10·-FINAL·April 2008 6-17 SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4B for White Mesa Uranium Mill
TABLE 6.1-9
PHASE 2-40 CFR 190 ANNUAL DOSE COMMITMENTS)FOR MEAT INGESTION
PATHWAY (COLORADO PLATEAU ORE)(mremlyr)
Location Age Group Oman"
Effectivel\Bonel\Avg.Lung'
Infant O.OOE+OO O.OOE+OO O.OOE+OO
Graziug Location I Child I.07E-02 5.35E-02 4.87E-02
Teeuage I.68E-02 2.78E-OI 4.26E-02
Adult I.22E-02 I.50E-OI 3.5IE-02
Infant O.OOE+OO O.OOE+OO O.OOE+OO
Grazing Location 2 Child 6.7IE-04 3.32E-03 2.80E-03
Teenage I.03E-03 I.75E-02 2.46E-03
Adult 7.39E-04 9.20E-03 2.03E-03
Note:
a)Assumes cattle will graze at the particular Grazing location for 2 months ofthe year.
b)Exclusive ofradon.
The annual doses to the population estimated within 50 miles (80 km)ofthe site are provided in
Table 6.1-10.
TABLE 6.1-10
PHASE 2-ANNUAL POPULATION DOSE COMMITMENTS WITHIN 50 MILES
(80 km)OF THE MILL FOR COLORADO PLATEAU ORE
ANNUAL POPULATION DOSE COMMITMENTS,
Organ PERSON-REM PER YEAR
Mill Operatious
Effective I.50E-OI
Bone 1.15E+OO
Avg.Lung I.56E-O I
Bronchi 8.66E+OO
The population dose arising from processing Colorado Plateau ore during Phase 2 is estimated at
0.15 person-rem.This can be compared to the dose from natural background sources of
radiation ofabout 360 mrem/yr as previously discussed in Phase 1.
The current population ofSan Juan County is about 14,400 people.Assuming everyone living in
San Juan County receives an annual dose of (about)360 mrem/yr,then the total dose due to
natural background is approximately 5184 person-rem.The theoretical incremental dose of
0.15 person-rem is clearly inconsequential by comparison.
34489-10 -FINAL -April 2008 6-18 SENES Consultants Limited
Proposed Development o/New Tailings Ce1l4Bfor White Mesa Uranium Mill
6.2 MILDOS-AREA RESULTS FOR ARIZONA STRIP ORE
The potential annual doses to the people living close to the mill and to the population living
within 50 miles (80 km)as a result of processing Arizona Strip ore was calculated using
MILDOS-AREA.
The MILDOS-AREA calculated total annual dose commitments (including radon)and 40 CFR
190 total annual dose commitments for processing of Arizona Strip ore are provided in
Sections 6.2.1 and 6.2.2,respectively.
6.2.1 R313-15-301 (l)(a)Regulatory Compliance
The MILDOS-AREA calculated total annual dose commitments (including radon)for Phases 1
and 2 are provided in this section.These doses are regulated by R313-15-30I(l)(a)which
requires that the dose to an individual member of the public shall not exceed 100 mrem/yr (radon
included).
Phase 1
Table 6.2-1 presents a summary ofthe individual dose commitments for the residential receptors
for the age group ofinfant,child,teenage and adult for Phase I.
34489-10 -FINAL -Apl'il2008 6-19 SENES Consultants Limited
Proposed Development ofNew Tailings Cell4Bfor White Mesa Uranium Mill
TABLE 6.2-1
PHASE I-COMPARISON OF ANNUAL DOSE COMMITMENTS WITH APPLICABLE
RADIATION PROTECTION STANDARDS (ARIZONA STRIP ORE)
Age Estimated Applicable Limit FractionLocationOrganDoseGroup(mrem/yr)(mrem/yr)of Limit
infant Effective 3.12E+00 100 3.12E-02
Bone 4.86E+00 --
Avg.Lung I.34E+00 --
Bronchi 2.72E+Ol --
Child Effective 2.32E+00 100 2.32E-02
Bone 3.48E+00 --
Avg.Lung 1.79E+00 --
Nearest Potential Bronchi 2.72E+Ol --
Resident (BHV-l)~_nage Effective 2.43E+00 100 2.43E-02
Bone l.23E+Ol --
Avg.Lung 1.43E+00 --
Bronchi 2.72E+Ol --
Adult Effective 2.14E+00 100 2.14E-02
Bone 5.42E+00 --
Avg.Lung 9.94E-Ol --
Bronchi 2.72E+Ol --
Infant Effective 6.60E-Ol 100 6.60E-03
Bone 7.65E-Ol --
Avg.Lung 2.58E-Ol ---
Bronchi 6.93E+00 --
Child Effective 5.46E-Ol 100 5.46E-03
Bone 5.80E-Ol ----
Avg.Lung 3.17E-Ol --
Nearest Historical Bronchi 6.93E+00 --
Resident (BHV-2)Teenage Effective 5.63E-Ol 100 5.63E-03
Bone I.92E+OO --
Avg.Lung 2.55E-Ol --
Bronchi 6.93E+00 --
Adult Effective 5.19E-Ol 100 5.19E-03
Bone 8.85E-Ol --
Avg.Lung 1.85E-Ol --
Bronchi 6.93E+00 --
34489-10 --FINAL-April 2008 6-20 SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4B for White Mesa Uranium Mill
TABLE 6.2-1 (Cont'd)
PHASE I-COMPARISON OF ANNUAL DOSE COMMITMENTS WITH APPLICABLE
RADIATION PROTECTION STANDARDS (ARIZONA STRIP ORE)
Age Estimated Applicable Limit FractionLocatiollOrgallDoseGroupImrem/vr)(mrem/yr)ofLimit
Illfallt Effective 1.96E+00 100 1.96E-02
Balle 2.86E+00 --
Aw.LUllg
..__.
7.91E-OI --
Bronchi 1.81E+01 --
Child Effective 1.50E+00 100 1.50E-02
Balle 2.05E+00 --
Avo.LUllo 1.06E+00 --
Nearest Actual Bronchi 1.81E+OI --
Residellt Teella~e Effective 1.56E+00 100 1.56E-02
Bone 7.18E+00 --
Avo.Lun"8.50E-01 --
Bronchi 1.8IE+OI ---
Adult Effective 1.40E+00 100 1.40E-02
Balle 3.I8E+00 --
Aw.LUII~5.96E-OI --
Bwnchi 1.81E+01 --
Illfallt Effective 4.68E-OI 100 4.68E-03
Bone 3.5IE-OI --
Aw.Lun~1.56E-OI --
BWllchi 5.72E+00 --
Child Effective 4.16E-OI 100 4.16E-03
Bone 2.53E-01 ----
Avo.LUllo 1.46E-01 --
White Mesa Bronchi 5.72E+00 --
Community Teenao-e Effective 4.19E-01 100 4.19E-03-
Balle 6.90E-OI --
Avo.LUll"1.16E-OI --
Bronchi 5.72E+00 --
Adult Effective 4.04E-OI 100 4.04E-03
Balle 3.5IE-OI --
Av".Lun"9.18E-02 --
Bronchi 5.72E+00 --
34489-10·--FINAL -April 2008 6-21 SENES Consultants Limited
Proposed Development o/New Tailings Ce1l4B/or White Mesa Uranium M:.cil:..-l _
TABLE 6.2-1 (Cont'd)
PHASE I-COMPARISON OF ANNUAL DOSE COMMITMENTS WITH APPLICABLE
RADIATION PROTECTION STANDARDS (ARIZONA STRIP ORE)
Age Estimated Applicable Limit FractionLocationOrganDoseGroup(mrem/vrl (mrem/yr)of Limit
Infant Effective 2.18E-OI 100 2.I8E-03
Bone 2.20E-0 I ---
Avg.Lung 7.98E-02 ---
Bronchi 2.39E+00 --
~Id Effective l.8SE-OI 100 l.8SE-03
Bone l.64E-OI --
Avg.Lung 9.22E-02 --
Blanding Bronchi 2.39E+00 --
Teenage Effective l.89E-OI 100 l.89E-03
Bone S.16E-OJ -----
Avg.Lung 7.49E-02 --
Bronchi 2.39E+00 --
Adult Effective l.78E-OI JOO l.78E-03
Bone 2.44E-OI --
Avg.Lung S.64E-02 --
Bronchi 2.39E+00 --
From Table 6.2-I,the total annual effective dose commitments are at most 3.I%(effective dose
for infant at BHV-I)of the R313-15-30I(l)(a)limit of 100 mrem/yr (radon included)to an
individual member of the public.Therefore,the predicted annual effective dose commitments
comply with R3 I3-15-I0I(I)(a).
In addition,Table 6.2-2 presents a summary of the annual dose commitments fi·om the meat
ingestion pathway for Grazing location I and 2.As before in the unlikely event that a receptor
consumed beef from one of the grazing locations,the total dose would remain well below
regulatory limits.
34489~IO -FINAL -April 2008 6-22 SENES Consultants Limited
____P_ro'-"'P'-'o-'-s-'-ecj Development o/New Tailings Cell 4B jor White Mesa Uranium Mill
TABLE 6.2-2
PHASE I-TOTAL ANNUAL DOSE COMMITMENTS FOR MEAT INGESTION
PATHWAY (ARIZONA STRIP ORE)(mrem/yr)
Location Age Group Orgau"
Effective'Boneft Avg.Lung'
Infant O.OOE+OO O.OOE+OO 0.00£+00
Child 2.75E-02 1.37E-OI 1.25E-OIGrazingLocationITeenage4.33E-02 7.16E-OI 1.09E-OI
Adult 3.13E-02 3.87E-01 9.03E-02
Infant 0.00£+00 0.00£+00 0.00£+00
Grazing Location 2 Child 1.87E-03 9.29E-03 7.93E-03
Teenage 2.90E-03 4.89E-02 6.94E-03
Adult 2.07E-03 2.57E-02 5.73E-03
Note:
a)Assumes cattle will graze at the particular Grazing location for 2 months ofthe year.
Phase 2
Table 6.2-3 presents a summary of the individual dose commitments for the residential receptors
for the age group ofinfant,child,teenage and adult for Phase 2.
TABLE 6.2-3
PHASE 2-COMPARISON OF ANNUAL DOSE COMMITMENTS WITH APPLICABLE
RADIATION PROTECTION STANDARDS (ARIZONA STRIP ORE)
Age Estimated Applicable Limit FractionLocationOrganDoseGroup(mrem/yr)(mrem/yr)of Limit
Infant Effective 3.IOE+00 100 3.IOE-02
Bone 4.81£+00 - -
Avg.Lung I.3IE+OO --
Bronchi 2.70E+OI --
Child Effective 2.30E+00 100 2.30E-02
Bone 3.42E+00 --
Avg.LU1:'jL 1.74£+00 - -
Nearest Potential Bronchi 2.70E+01 --
Resident (BHV-1)Teenage Effective 2.40£+00 100 2.40E-02
Bone 1.21E+01 --
Avg.Lung 1.40E+00 --
_I3ronchi 2.70E+OI -----
Adult Effective 2.12£+00 100 2.12E-02
Bone 5.3IE+00 --
Avg.Lung 9.7IE-OI --
Bronchi 2.70E+01 --
34489-10 "_.FINAL-April 2008 6-23 SENES Consultants Limited
Proposed Development ofNew Tailings Cell 48for White Mesa Uranium Mill-------
TABLE 6.2-3 (Cont'd)
PHASE 2-COMPARISON OF ANNUAL DOSE COMMITMENTS WITH APPLICABLE
RADIATION PROTECTION STANDARDS (ARIZONA STRIP ORE)
Location Age Organ Estimated Dose Applicable Limit Fraction
Group fmrem/Vl')'fmrem/vr)of Limit
Infant Effective 6.59E-OI 100 6.59E-03-
Bone 7.60E-OI --
Avg.2.56E-0I --Lung ....._-
Bronchi 6.93E+00 ----
Child Effective 5A5E-OI 100 5A5E-03
Bone 5.75E-OI --
Avg.3.14E-OI --Lung
Nearest Historical Bronchi 6.93E+OO --
Resident (BHV-2)Teenage Effective 5.62E-OI 100 5.62E-03
Bone 1.91E+00 --
Avg.2.52E-OI --Lung
Bronchi 6.93E+00 --
Adult Effective 5.18E-OI 100 5.18E-03
Bone 8.76E-OI --
Avg.1.84E-OI --Lung
Bronchi 6.93E+00 --f---
Infant Effective 1.95E+00 100 1.95E-02
Bone 2.83E+00 --
Avg.7.77E-OI --Lung
Bronchi 1.80E+OI --
Child Effective 1.49E+OO 100 1.49E-02
Bone 2.02E+OO --
Avg.1.03E+00 --Lung
Nearest Actual Bronchi 1.80E+OI --
Resident Teenage Effective 1.55E+00 100 1.55E-02
Bone 7.06E+00 --
Avg.8.32E-OI --Lung
Bronchi 1.80E+OI --
Adult Effective 1.39E+00 100 1.39E-02
Bone 3.13E+00 --
Avg.5.84E-0 I --Lung
Bronchi 1.80E+OI --
34489·!0-FINAL -April 2008 6-24 SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4B for White Mesa Uranium Mil~_
TABLE 6.2-3 (Cont'd)
PHASE 2-COMPARISON OF ANNUAL DOSE COMMITMENTS WITH APPLICABLE
RADIATION PROTECTION STANDARDS (ARIZONA STRIP ORE)
Location Age Ol"gan Estimated Dose Applicable Limit Fraction
CI"OnD (ml"em!vl"j (ml"em!vl"j of Limit
Infant Effective 4.69E-Ol 100 4.69E-03-_.__.---
Bone 3.49E-0 I --
Avg.1.55E-Ol --
._..._._--.1.unL_------_._....._----_.---_.._._.--
Bronchi 5.75E+00 --
Child Effective 4.l7E-Ol 100 4.17E-03
Bone 2.52E-Ol --
Avg.1.45E-Ol --Lung
White Mesa Bronchi 5.75E+00 --
Community Teenage Effective 4.20E-Ol 100 4.20E-03
Bone 6.85E-Ol --
Avg.l.l5E-Ol --Lung
Bronchi 5.75E+00 --
Adult Effective 4.05E-Ol 100 4.05E-03
Bone 3.48E-Ol --
Avg.9.l4E-02 --Lung
Bronchi 5.75E+00 --
Infant Effective 2.l9E-Ol 100 2.l9E-03
Bone 2.20E-Ol --
Avg.7.98E-02 --Lung
Bronchi 2.40E+00 --
Child ~!ective 1.86E-Ol 100 1.86E-03-----
Bone 1.64E-Ol --
Avg.9.22E-02 --
-----Lung .1---
Blanding Bronchi 2.40E+00 --
Teenage Effective 1.90E-Ol 100 1.90E-03
Bone 5.l5E-Ol --
Avg.7.49E-02 --Lun"
Bronchi 2.40E+00 --
Adult Effective 1.79E-Ol 100 1.79E-03
Bone 2.44E-Ol -1--------_._.--_._----------Avg.5.65E-02 --Lun"
Bronchi 2.40E+00 --
34489-10 -FINAL-April 2008 6-25 SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4B for White Mesa Uranium Mill
From Table 6.2-3,the total annual effective dose commitments are at most 3.1 %(effective dose
for infant at BHV-l)of the R313-15-30I(l)(a)limit of 100 mrem/yr (radon included)to an
individual member of the public.Therefore,the predicted annual effective dose commitments
comply with R313-15-1 Ol(l)(a).
In addition,Table 6.2-4 presents a summary of the annual dose commitments from the meat
ingestion pathway for Grazing location I and 2.As before in the unlikely event that a receptor
consumed beef from one of the grazing locations,the total dose would remain well below
regulatory limits.
TABLE 6.2-4
PHASE 2-TOTAL ANNUAL DOSE COMMITMENTS FOR MEAT INGESTION
PATHWAY (ARIZONA STRIP ORE)(mremlyr)
Location Age Group Organb
EffectiveR Bonea Avg.Lung'
Infant O.OOE+OO O.OOE+OO O.OOE+OO
Grazing Location 1 Child 2.73E-02 1.36E-OI 1.24E-OI
Teenage 4.29E-02 7.IOE-OI 1.08E-OI
Adult 3.IOE-02 3.83E-OI 8.94E-02
Infant O.OOE+OO O.OOE+OO O.OOE+OO
Grazing Location 2 Child 1.71E-03 8.50E-03 7.18E-03
Teenage 2.65E-03 4.48E-02 6.28E-03
Adult 1.89E-03 2.35E-02 5.18E-03
Note:
a)Assumes cattle will graze at the particular Grazing location for 2 months ofthe year.
6.2.2 40 CFR 190 Regulatory Compliance
MILDOS-AREA calculated 40 CFR 190 doses (excludes radon).These doses are regulated by
the 40 CFR 190 criterion of 25 mrem/yr to the whole body (excluding the dose due to radon)
(EPA 2002)or to any organ of the body.The 40 CFR 190 doses are also used to demonstrate
compliance with R313-15-101(4)(10 CFR 20.1101(d)).The licensee must demonstrate as an
ALARA goal,that total effective dose equivalent to the individual member ofthe public likely to
receive the highest total effective dose equivalent will not exceed 10 mrem/yr (absent of the
radon dose).
Phase 1
Table 6.2-5 presents a summary ofthe 40 CFR 190 individual dose commitments for residential
receptors for the age group ofinfant,child,teenage and adult for Phase I.
34489-10 ~FINAL -April 2008 6-26 SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4Bfor White Mesa Uranium Mill
TABLE 6.2-5
PHASE I-COMPARISON OF 40 CFR 190 ANNUAL DOSE COMMITMENTS WITH
APPLICABLE RADIATION PROTECTION STANDARDS
(ARIZONA STRIP ORE)
Location Age Organ Estimated Dose Applicable Limit Fraction
Gronn (mrem!vr)'(mrem!vr\of Limit
Infant Effective 1.39E+OO 25 5.55E-02
Bone 4.76E+OO 25 1.90E-Ol -
Avg.1.24E+OO 25 4.95E-02Lung
Bronchi 2.48E-03 no limit given -
Child Effective 5.92E-O 1 25 2.37E-02---
Bone 3.37E+OO 25 1.35E-Ol
Avg.1.69E+OO 25 6.74E-02Lung
Nearest Potential Bronchi 2.48E-03 no limit given -
Resident (BHV-I)Teenaae Effective 7.03E-Ol 25 2.8lE-02
Bone l.22E+Ol 25 4.88E-O!
Avg.l.33E+OO 25 5.3lE-02Lung
Bronchi 2.48E-03 no limit given -
Adult Effective 4.l4E-Ol 25 1.66E-02
Bone 5.32E+OO 25 2.!3E-Ol
Avg.8.93E-Ol 25 3.57E-02Lung
Bronchi 2.48E-03 no limit given -..-
Infant Effective 2.06E-Ol 25 8.24E-03
Bone 7.20E-Ol 25 2.88E-02
Avg.2.l8E-O!25 8.73E-03Lung
Bronchi 3.54E-04 no limit given -
Child Effective 9.l9E-02 25 3.68E-03
Bone 5.32E-Ol 25 2.13E-02
Avg.2.73E-Ol 25 1.09E-02Lung
Nearest Historical Bronchi 3.54E-04 no limit given -
Resident (BHV-2)Teenage Effective 1.09E-Ol 25 4.34E-03
Bone 1.86E+OO 25 7.44E-02
Avg.2.llE-Ol 25 8.44E-03Lung
Bronchi 3.54E-04 no limit given -
Adult Effective 6.49E-02 25 2.60E-03
Bone 8.30E-O I 25 3.32E-02
Avg.1.43E-O I 25 5.73E-03LUlla
Bronchi 3.54E-04 no limit given -
34489-10 -FINAL-April 2008 6-27 SENES Consultants Limited
Proposed Development ofNew Tailings Ce1l4B for White Mesa Uranium Mill
TABLE 6.2-5 (Cont'd)
PHASE I-COMPARISON OF 40 CFR 190 ANNUAL DOSE COMMITMENTS WITH
APPLICABLE RADIATION PROTECTION STANDARDS
(ARIZONA STRIP ORE)
Location Age Organ Estimated Dose Applicable Limit Fraction
GrouD (mrem/vr)(mrem/vr)ofLimit
Infant Effective 8.11E-Ol 25 3.24E-02
Boue 2.79E+00 25 LlIE-OI
Avg.7.16E-Ol 25 2.86E-02Lung
Bronchi 1.44E-03 no limit given ._-
Child Effective 3.44E-Ol 25 1.38E-02
Bone 1.97E+00 25 7.88E-02
Avg.9.78E-Ol 25 3.91E-02Lung
Nearest Actual Bronchi 1.44E-03 no limit given -
Resident Teenage Effective 4.09E-Ol 25 I.64E-02
Bone 7.09E+00 25 2.83E-Ol
Avg.7.71E-Ol 25 3.08E-02Lung
Bronchi 1.44E-03 no limit given -
Adult Effective 2.41E-Ol 25 9.64E-03
Bone 3.09E+00 25 1.24E-Ol
Avg.5.17E-Ol 25 2.07E-02Lung
Bronchi 1.44E-03 n~limit given -
Infant Effective 8.58E-02 25 3.43E-03
Bone 3.02E-Ol 25 1.21 E-02
Avg.Ll6E-01 25 4.64E-03Lung
Bronchi 1.08E-04 no limit ~iven ---_.
Child Effective 3.33E-02 25 1.33E-03
Bone 1.99E-0 I 25 7.95E-03
Avg.9.80E-02 25 3.92E-03Lung
White Mesa Bronchi 1.08E-04 no limit given -
Community -
Teenage Effective 3.51E-02 25 1.41 E-03
Bone 5.90E-0 I 25 2.36E-02
Avg.6.92E-02 25 2.77E-03Lung
Bronchi 1.08E-04 no limit given -
Adult Effective 2.21E-02 25 8.85E-04
Bone 2.82E-Ol 25 Ll3E-02
Avg.4.87E-02 25 1.95E-03
--Lung
Bronchi 1.08E-04 no limit given -
34489-10 -FINAL-April 2008 6-28 SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4B for White Mesa Uranium Mill
TABLE 6.2-5 (Cont'd)
PHASE I-COMPARISON OF 40 CFR 190 ANNUAL DOSE COMMITMENTS WITH
APPLICABLE RADIATION PROTECTION STANDARDS
(ARIZONA STRIP ORE)
Location Age Organ Estimated Dose Applicable Limit Fraction
Gronp (mrem/yr)(mrem/yr)ofLimit
Infant Effective 5.64E-02 25 2.26E-03
Bone 1.96E-O I 25 7.83E-03
Avg.6.08E-02 25 2.43E-03Lung
Bronchi 8.89E-05 no limit given -
Child Effective 2.35E-02 25 9.4!E-04
Bone 1.37E-O!25 5.48E-03
Avg.6.86E-02 25 2.74E-03Lung
Blanding Bronchi 8.89E-05 no limit given -
Teenage Effective 2.70E-02 25 1.08E-03
Bone 4.62E-O!25 1.85E-OZ-
Avg.5.20E-02 25 2.08E-03Lung
Bronchi 8.89E-05 no limit given -
Adult Effective 1.63E-02 25 6.50E-04
Bone 2.08E-O!25 8.32E-03
Avg.3.55E-02 25 1.42E-03Lung
Bronchi 8.89E-05 no limit given -
From Table 6.5-2,the 40 CFR 190 annual dose eommitments are at most 48.8%(dose to the
bone for the teenage at SHV-I)ofthe 40 CFR 190 dose eriterion of25 mrem/yr.In addition,the
40 CFR 190 annual effeetive dose eommitments demonstrate eomplianee with the R313-15-
101(4)(10 CFR 20.1101(d»ALARA goal of 10 mrem/yr to the individual member ofthe publie
likely to reeeive the highest total effeetive dose equivalent.The maximum total effeetive dose
equivalent was 1.39 mrem/yr (infant at SHV-I),or 13.9%ofthe 10 mrem/yr goal.
In addition,Table 6.2-6 presents a summary of the 40 CFR 190 annual dose eommitments from
the meat ingestion pathway for Grazing loeation I and 2.As before in the unlikely event that
someone was to eonsume beef from grazing area I or 2,the total dose would be small and well
below regulatory limits.
34489-I0 -FINAL-April 2008 6-29 SENES Consultants Limited
P!oposed Development ofNew Tailings Ce1l4B for White Mesa Uranium Mill
TABLE 6.2-6
PHASE 1-40 CFR 190 ANNUAL DOSE COMMITMENTS FOR MEAT INGESTION
PATHWAY (ARIZONA STRIP ORE)(mrem/yr)
Location Age Group Organ
Effective"Bonea Avg.Lnng"
Infant O.OOE+OO O.OOE+OO O.OOE+OO
Grazing Location 1 Child 2.75E-02 1.37E-OI 1.25E-OI
Teenage 4.33E-02 7.16E-OI 1.09E-OI
Adult 3.13E-02 3.87E-OI 9.03E-02
Infant O.OOE+OO O.OOE+OO O.OOE+OO
Grazing Location 2 Child 1.87E-03 9.27E-03 7.90E-03
Teenage 2.88E-03 4.87E-02 6.92E-03
Adult 2.06E-03 2.57E-02 5.7IE-03
Note:
a)Assumes cattle will graze at the particular Grazing location for 2 months ofthe year.
b)Exclusive ofradon.
The annual doses to the population estimated within 50 miles (80 km)ofthe site are provided in
Table 6.2-7.
TABLE 6.2-7
PHASE I-ANNUAL POPULATION DOSE COMMITMENTS WITHIN 50 MILES
(80 km)OF THE MILL FOR ARIZONA STRIP ORE
ANNUAL POPULATION DOSE COMMITMENTS,
Organ PERSON-REM PER YEAR
Mill Operations
Effective 3.08E-01
Bone 2,48E+00
Avg.Lung 3.28E-OI
Bronchi 1.64E+01 ._-
The population dose arising from processing Arizona Strip ore during Phase I is estimated at
0.31 person-rem.This can bc compared to the dose from natural background sources of
radiation ofabout 360 mrem/yr as previously discussed.
The CUtTent population of San Juan County is about 14,400 people.Assuming everyone living in
San Juan County receives an annual dose of (about)360 mrem/yr,then the total dose due to
natural background is approximately 5184 person-rem.The theoretical incremental dose of
0.31 person-rem is clearly inconsequential by comparison.
34489~IO -FINAL -April 2008 6-30 SENES Consultants Limited
Proposed Development o/New Tailings Ce1l4B/or White Mesa Uranium Mill
Phase 2
Table 6.2-8 presents a summary of the 40 CFR 190 individual dose commitments for residential
receptors for the age group of infant,child,teenage and adult for Phase 2.
TABLE 6.2-8
PHASE 2-COMPARISON OF 40 CFR 190 ANNUAL DOSE COMMITMENTS WITH
APPLICABLE RADIATION PROTECTION STANDARDS (ARIZONA STRIP ORE)
Location Age Organ Estimated Dose Allplieable Limit Fraction
Gronp (mrem!vr)(mrem!vr)ofLimit
Infant Effective l.38E+OO 25 5.50E-02
Bone 4.7IE+OO 25 1.88E-OI•.
Avg.l.2IE+OO 25 4.84E-02Lunrr
Bronchi 2.45E-03 no limit given ..-
Child Effective 5.81 E-O I 25 2.32E-02
Bone 3.3IE+OO 25 l.32E-OI
Avg.I.64E+OO 25 6.58E-02Lung
Nearest Potential Bronchi 2.45E-03 no limit given -
Resident (BHV-I)Teenage Effective 6.89E-Ol 25 2.76E-02
Bone 1.20E+Ol 25 4.79E-OI
Avg.1.29E+OO 25 5.18E-02Lung
Brouchi 2.45E-03 no limit given -
Adult Effective 4.05E-OI 25 1.62E-02
Bone 5.21E+OO 25 2.08E-OI_.-
Avg.8.7IE-Ol 25 3.48E-02Lung
Bronchi 2.45E-03 no limit given --
34489-10 -FINAL -April 2008 6-31 SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4Bfor White Mesa Uranium M!."'ll _
TABLE 6.2-8 (Cont'd)
PHASE 2-COMPARISON OF 40 CFR 190 ANNUAL DOSE COMMITMENTS WITH
APPLICABLE RADIATION PROTECTION STANDARDS
(ARIZONA STRIP ORE)
Location Age Organ Estimated Dose Applicable Limit Fl'action
Grouo (mrem/vr)(mrem/vr)of Limit
Infant Effective 2.05E-Ol 25 8.20E-03
Bone 7.16E-OI 25 2.86E-02.•.
Avg.2.16E-OI 25 8.64E-03Lung
Bronchi 3.53E-04 no limit given -
Child Effective 9.11 E-02 25 3.64E-03
Bone 5.27E-0I 25 2.11E-02
Avg.2.70E-Ol 25 1.08E-02Lung
Nearest Historical Bronchi 3.53E-04 no limit give:l -
Resident (BHV-2)Teenage Effective 1.07E-OI 25 4.30E-03
Bone 1.84E+00 25 7.38E-02
Avg.2.09E-OI 25 8.35E-03Lung
Bronchi 3.53E-04 no limit given -
Adult Effective 6.42E-02 25 2.57E-03
Bone 8.22E-OI 25 3.29E-02
Avg.1.42E-OI 25 5.66E-03Lu'!.8
Bronchi 3.53E-04 no limit given -
Infant Effective 8.04E-OI 25 3.22E-02
Bone 2.76E+00 25 1.10E-Ol
Avg.7.02E-Ol 25 2.81E-02Lung
Bronchi 1.42E-03 not limited -_.
Child Effective 3.39E-OI 25 1.35E-02
Bone 1.94E+00 25 7.74E-02
Avg.9.57E-Ol 25 3.83E-02Lung
Nearest Actual Bronchi 1.42E-03 not limited -
Resident Teenage Effective 4.02E-OI 25 1.61E-02
Bone 6.97E+00 25 2.79E-OI
Avg.7.54E-OI 25 3.02E-02Lung
Bronchi 1.42E-03 not limited -
Adult Effective 2.36E-Ol 25 9.46E-03
Bone 3.03E+00 25 1.21E-Ol
Avg.5.06E-OI 25 2.02E-02Lung
Bronchi 1.42E-03 not limited -
34489-10 -FINAL -April 2008 6-32 SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4Bfor White Mesa Uranium Mill
TABLE 6.2-8 (Cont'd)
PHASE 2-COMPARISON OF 40 CFR 190 ANNUAL DOSE COMMITMENTS WITH
APPLICABLE RADIATION PROTECTION STANDARDS
(ARIZONA STRIP ORE)
Location Age Organ Estimated Dose Applicable Limit Fraction
Group (mrem/vr)(mrem/vr)ofLimit
Infant Effective 8.53E-02 25 3.4IE-03-
Bone 3.00E-OI 25 I.20E-02
Avg.I.l5E-Ol 25 4.59E-03Lung
Bronchi I.08E-04 not limited -
Child Effective 3.30E-02 25 I.32E-03.-
Bone I.97E-Ol 25 7.87E-03
Avg.9.68E-02 25 3.87E-03Lung
White Mesa Bronchi I.08E-04 not limited -
Community Teenage Effective 3.48E-02 25 I.39E-03
Bone 5.85E-OI 25 2.34E-02
Avg.6.83E-02 25 2.73E-03Lung
Bronchi I.08E-04 not limited -
Adult Effective 2.19E-02 25 8.75E-04
Bone 2.79E-OI 25 I.I2E-02
Avg.4.8lE-02 25 I.92E-03Lung
Bronchi I.08E-04 not limited -
Infant Effective 5.64E-02 25 2.26E-03
Bone I.96E-Ol 25 7.82E-03
Avg.6.07E-02 25 2.43E-03Lung_.
Bronchi 8.88E-05 not limited -
Child Effective 2.35E-02 25 9.40E-04..-
Bone I.37E-Ol 25 5.47E-03
Avg.6.84E-02 25 2.74E-03Lung
Blanding Bronchi 8.88E-05 not limited -
Teenage Effective 2.70E-02 25 I.08E-03
Bone 4.6lE-Ol 25 I.85E-02
Avg.5.l9E-02 25 2.08E-03Lung
Bronchi 8.88E-05 not limited -
Adult Effective I.62E-02 25 6.49E-04
Bone 2.08E-Ol 25 8.3 IE-O:i-
Avg.3.55E-02 25 I.42E-03Lung
Bronchi 8.88E-05 not limited -
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From Table 6.2-8,the 40 CFR 190 annual dose commitments are at most 48%(dose to the bone
for the teenage at BHV-I)of the 40 CFR 190 dose criterion of 25 mrem/yr.In addition,the
40 CFR 190 annual effective dose commitments demonstrate compliance with the R313-15-
101(4)(10 CFR 20.1101 (d))ALARA goal of 10 mrem/yr to the individual member of the public
likely to receive the highest total effective dose equivalent.The maximum total effective dose
equivalent was 1.38 mrem/yr (infant at BHV-I),or 13.8%ofthe 10 mrem/yr goal.
In addition,Table 6.2-9 presents a summary of the 40 CFR 190 annual dose commitments from
the meat ingestion pathway for Grazing location I and 2.As before in the unlikely event that
someone was to consume beef from grazing area I or 2,the total dose would be small and well
below regulatory limits.
TABLE 6.2-9
PHASE 2-40 CFR 190 ANNUAL DOSE COMMITMENTS FOR MEAT INGESTION
PATHWAY (ARIZONA STRIP ORE)(mremlyr)
Location Age Group Organ
Effective'Ronca AVI'.Lnnl!'
Infant O.OOE+OO O.OOE+OO O.OOE+OO
Grazing Location I Child 2.73E-02 l.36E-OJ l.24E-OI
Teenage 4.29E-02 7.10E-OJ l.08E-OI
Adult 3.10E-02 3.83E-OI 8.94E-02
Jnfant O.OOE+OO O.OOE+OO O.OOE+OO
Grazing Location 2 Child l.71E-03 8A8E-03 7.J4E-03
Teenage 2.63E-03 4A6E-02 6.25E-03
Adult l.88E-03 2.35E-02 5.17E-03
Note:
a)Assumes cattle will graze at the particular Grazing location for 2 months ofthe year.
b)Exclusive ofradon.
The annual doses to the population estimated within 50 miles (80 km)of the site are provided in
Table 6.2-10.
TABLE 6.2-10
PHASE 2-ANNUAL POPULATION DOSE COMMITMENTS WITHIN 50 MILES
(80 km)OF THE MILL FOR ARIZONA STRIP ORE
ANNUAL POPULATION DOSE COMMITMENTS,
Organ PERSON-REM PERYEAR
-Mill Operations
Effective 3.15E-OI
Bone 2.55E+OO
Avg.Lung 3.34E-OI
Bronchi l.65E+OI
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The population dose arising from processing Arizona Strip ore during Phase 2 is estimated at
0.32 person-rem.This can be compared to the dose from natural background sources of
radiation in the Colorado Plateau of about 360 mrem/yr as previously discussed.
The current population ofSan Juan County is about 14,400 people.Assuming everyone living in
San Juan County receives an annual dose of (about)360 mrem/yr,then the total dose due to
natural background is approximately 5184 person-rem.The theoretical incremental dose of
0.32 person-rem is clearly inconsequential by comparison.
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7.0 KEY OBSERVATIONS
As described in Section 1.0,milling of conventional ore is scheduled for the Spring of 2008
when the milling of currently available alternate feed materials is completed (OUSA 2007a).
The objective of this dose assessment was to extend the previous report (SENES 2007)to
incorporate the dose from the proposed development of new tailings cell 4B,in support of a
license amendment application for the construction and operation ofthat cell.
The NRC-approved MILOOS-AREA was used to estimate the dose commitments received by
individuals and the general population within a 50 mile (80 km)radius of the site for the
processing of Colorado Plateau or Arizona Strip ore separately.In each scenario,the doses
arising from the emissions of dust and radon from the mill area and ore pads were assumed to be
the same as in the previous 2007 report since the scenarios both involve the processing of
Colorado Plateau and Arizona Strip ores.Therefore,MILOOS-AREA runs from the previous
repOlt were revised to exclude the tailings cells.The doses from the tailings cells were estimated
in separate MILOOS-AREA runs and added to the dose from the mill area and ore pads.Table
7-1 provides a summary of the source telms included in Phases I and 2.
TABLE 7-1
SOURCE TERMS INCLUDED IN PHASES 1 AND 2
Source Term Phase 1 Phase 2
Mill area included included
Ore Pads included included
Tailings Cell 2 with Interim Soil Cover included included
Tailings Cell 3 active interim soil cover
Tailings Ce1l4A active active
Tailings Ce1l4B excluded active
The wind erosion and radon release rates from the tailings cells (active and with interim soil
cover)were modelled by using a maximal worst case approach.
Each active tailings cell was modelled to have an active exposed (non-solution)tailings solids
area of 10 acres (Le.,the maximum uncovered tailings solids area at any time allowed under
NESHAPs Regulation 40 CFR 61.252(b),Subpart W)since it is not possible to predict the
distribution of uncovered tailings between the active cells at any given time.As a result,the
release rate of wind-eroded tailings dust was estimated at 10 acres at all times for each active
cell.The total annual radon release rate was estimated by assuming a radon release rate of 20
pCi/m2s (i.e.,maximum radon-222 emissions to ambient air from an existing uranium mill pile)
over the entire area ofeach cell consistent with NESHAPs.
The tailings cells (2 and 3)with interim soil cover were assumed to be the entire areas of each
cell;however,only radon is released at a rate of 10 pCi/m2s after the application of the soil
cover.
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The calculated total annual effective dose commitments (including radon)calculated using
MILDOS-AREA were compared to the Utah Administrative Code R313-15-301(1)(a)
requirement that the dose to individual members of the public shall not exceed 100 mrem/yr
(radon included).For processing of Colorado Plateau ore,the maximum total annual effective
dose commitments was calculated to be a maximum of 1.4 mrem/yr for an infant at the nearest
potential resident,BHV-I (Tables 6.1-1 and 6.1-3)(i.e.,effective dose)and is about 1.4%ofthe
R313-15-30I(l)(a)limit of 100 mrem/yr (radon included)to an individual member of the public
for Phases I and 2.For processing of Arizona Strip ore,the total annual effective dose
commitments were calculated to be a maximum of 3.1 mrem/yr for an infant at the nearest
potential resident,BHV-I (Tables 6.2-1 and 6.2-3)(i.e.,effective dose)and is about 3.1%ofthe
100 mrem/yr limit (radon included)to an individual member of the public for Phases I and 2.
Overall,using conservative assumptions,the predicted annual effective dose commitments for
Phases I and 2 comply with R313-15.
In addition,our MILDOS-AREA calculated 40 CFR 190 annual dose commitments (excluding
radon)were compared to the 40 CFR 190 criterion,which is 25 mrem/yr to the whole body
(excluding the dose due to radon)and 25 mrem/yr to any other organ to any member of the
public (EPA 2002).The 40 CFR 190 doses were also used to demonstrate compliance with the
ALARA goal set out in R313-15-101(4)(10 CFR 20.1101(d))(i.e.,the ALARA goal is to
demonstrate that total effective dose equivalent to the individual member of the public likely to
receive the highest total effective dose equivalent will not exceed 10 mrem/yr (absent of the
radon dose)).For processing of Colorado Plateau ore,the 40 CFR 190 annual dose
commitments were calculated to be a maximum of 4.8 mrem/yr for a teenager at the nearest
potential resident,BI-IV-I (Tables 6.1-5 and 6.1-8)(i.e.,dose to the bone)and is about 19%of
the 40 CFR 190 dose criterion of 25 mrem/yr,for Phases I and 2.Further,the 40 CFR 190
annual effective dose commitments demonstrate compliance with the R313-15-101(4)(10 CFR
20.IIOI(d))ALARA goal of 10 mrem/yr to the individual member of the public likely to receive
the highest total effective dose equivalent (the maximum total effective dose equivalent (radon
excluded)during Phases I and 2 was 0.545 mrem/yr for an infant at BHV-I).For Arizona Strip
ore,the 40 CFR 190 annual dose commitments were at most 12 mrem/yr for a teenage at the
nearest potential resident,BHV-I (Tables 6.2-5 and 6.2-8)(i.e.,dose to the bone)and is about
49%of the 40 CFR 190 dose criterion of 25 mrem/yr for Phases I and 2.Further,the 40 CFR
190 annual effective dose commitments demonstrate compliance with the R313-15-101(4)(10
CFR 20.1101(d))goal of 10 mrem/yr to the individual member of the public likely to receive the
highest total effective dose equivalent (the maximum total effective dose equivalent (radon
excluded)during Phases I and 2 was 1.39 mrem/yr for an infant at BHV-I).Overall,using
conservative assumptions,ore processing in Phases I and 2 comply with the requirements of 40
CFR 190 and the ALARA goal set out in R313 -15-101(4).
34489-10-FINAL-April 2008 7-2 SENES Consultants Limited
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8.0 REFERENCES
Argonne National Laboratory (ANL)1998a.MILDOS-AREA,Version 2.2013,Developed at the
Environmental Assessment Division
Argonne National Laboratory (ANL)1998b.
Environmental Assessment Division
MILDOS-AREA User's Guide (Draft),
Code of Federal Regulations (CFR)Title 10 Part 20 Standardsfor Protection Against Radiation.
May.
Dames &Moore 1978.Environmental Report:White Mesa Uranium Project San Juan County,
Utah for Energy Fuels Nuclear,Inc.January.
Denison Mines (USA)Corp.(DUSA)2007a.Press Release:Denison Announces Operations
Update.January 30.
Denison Mines (USA)Corp.(DUSA)2007b.2006 ALARA Report.May 10.
EnecoTech Environmental Consultants 1991a.MILDOS Modeling Results (Letter),Prepared for
Umetco Minerals.October 31.
EnecoTech Environmental Consultants 1991b.MILDOS Modeling Correction (Letter),Prepared
for Umetco Minerals.November 27.
United States Environmental Protection Agency (EPA)1989.Code of Federal (CFR)
Regulations Title 40 Part 61 National Emission Standards for Hazardous Air Pollutants
(NESHAPs),Subpart W.December.
United States Environmental Protection Agency (EPA)2002.Code of Federal (CFR)
Regulations Title 40 Part 190 Environmental Radiation Protection for Nuclear Power
Operations.FeblUary.
Google 2005.Google Earth Pro 3.0.0762,November.
Intemational Commission on Radiological Protection ([eRP)1959.Report ofICRP Committee
lIon Permissible Dosefor Internal Radiation,Health Physics 3:1-380,1960.
International Commission on Radiological Protection (ICRP)1966.Deposition and retention
models for internal dosimetly of the human respiratory tract.Health Physics 12;
173-207.
34489H10 -FINAL~April 2008 8-1 SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4B for White Mesa Uranium Mill
International Commission on Radiological Protection (ICRP)1971.Recommendations of the
International Commission on Radiological Protection.ICRP Publication lOA.Pergamon
Press,New York.
Intemational Commission on Radiological Protection (ICRP)1972.The Metabolism of
Compounds ofPlutonium and Other Actinides.ICRP Publication 19,Pergamon Press.
International Commission on Radiological Protection (ICRP)1979.Limits for Intakes of
Radionuclides by Workers (adoptedfrom July 1978).ICRP Publication 30.
Landau,S.2007.Email:RE:34489-Preliminary Mildos Results and Emissions Calculations.
Received Feb.13/07.
National Council on Radiation Protection and Measurements (NCRP)1987.Report No.94.
Exposure of Population in the United States and Canada from Natural Background
Radiation
United States Nuclear Regulatory Commission (NRC)1979.Final Environmental Statement
Related to the Energy Fuels Nuclear,Inc,NUREG-0556.Docket No.40-8681.May.
United States Nuclear Regulatory Commission (NRC)1980.Final Generic Environmental
Impact Statement on Uranium Milling Project M-25,NUREG-0706 Vol.3.September.
United States Nuclear Regulatory Commission (NRC)1987.Methods for Estimating
Radioactive and Toxic Airborne Source Termsfor Uranium Milling Operations,March.
SENES Consultants Limited (SENES)2007.Dose Assessment in Support of the License
Renewal Application &Environmental Report for the White Mesa Mill.Prepared for
Denison Mincs (USA)Corp.February.
Strenge,D.L.and Bander,TJ.1981.MILDOS-A Computer Program for
Environmental Radiation Doses from Uranium Recovery
NUREGICR-2011.Prepared for U.S.Nuclear Regulatory Commission.
Turk,D.2007a.Email to A.Ho:RE:Receptor GPs.Received February 14-15.
Calculating
Operations,
Turk,D.2007b. Email to D.Chambers:FW:Additional Weather Information.Received Feb 7.
Yu,C.1992.Calculation of Radiation Dose from Uranium Recovery Operations for Large
Area-Sources.Argonne National Laboratory.
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APPENDIX A
HISTORY OF MILDOS
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APPENDIX A HISTORY OF MILDOS
The MILDOS computer code was developed from the versIon IV for Argonne National
Laboratory's (ANL's)Uranium Dispersion and Dosimetry (UDAD)computer program 198I.
The MILDOS program was based on the models and assumptions from NRC Draft Regulatory
Guide RH802-4 (Calculational Models for Estimating Radiation Doses to Man from Airbome
Radioactive Material Resulting from Uranium Milling Operation)and portions of the UDAD
document (Strenge and Bender 1981).
In 1989,ANL developed the MILDOS-AREA code by modifying the MILDOS code developed
in 1981.The MILDOS-AREA code was designed for use on IBM or IBM compatible
computers;the changes made were intended to enhance capabilities for calculating dose from
large area-sources and updated dosimetry calculations.The major revision from the original
MILDOS code is the treatment of atmospheric dispersion from area sources;MILDOS-AREA
substituted a finite-element approach for the virtual-point source method (the algorithm used in
the original MILDOS code)when specified by the user.The new approach subsequently led to a
reduction in the number of sources from 20 to lOin MILDOS-AREA due to the fact that a large
area can be considered as a single source rather than two or more point sources.
The intemal dosimetry calculations were also updated in MILDOS-AREA.In the original
version of MILDOS,the dose to exposed individual is calculated for comparison with
requirements of both 40 CFR 190 and 10 CFR 20 (R313-15).The calculations of ingestion
DCFs were based on ICRP Publication 2 and lOA's ingestion models (ICRP 1966).The
inhalation DCFs are calculated by the ANL computer program UDAD in accordance with Task
Group on Lung Dynamics Lung Model (TGLM)of the International Commission on
Radiological Protection (ICRP 1966,ICRP 1972).ICRP Publication 19 (ICRP 1972)gives dose
commitments to adult members of the public at age 20 that are assumed to live another 50 years.
DCFs are provided as a function of patticle size and organ for the radionuclides U-238,U-234,
Th-230,Ra-226,Pb-210,Po-210 and Bi-210.The inhalation dose factors incorporated into
MILDOS-AREA are calculated using the dosimetric model from ICRP Publication 30 (ICRP
1979)(Yu 1992);the inhalation dose factors are provided for the age groups of infant,child,
teenager and adult.However,these factors are fixed internally in the code,and are not patt of
the input options.The annual average air concentrations were computed to the maximum
pelmissible concentrations (MPCs)in 10 CFR 20.The MPCs m
10 CFR 20 (incorporated by reference in R313-15)were revised in 1994 to incorporate the
updated dosimetry to the I CRP 1978 recommendations.
In 1997,the MILDOS-AREA code was updated to meet the requirements of the revised
10 CFR 20.The dose limit to the general public also changed;which led to a revised calculation
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of the allowable concentrations (ALCs)for unrestricted areas,with MPC replaced with the term
"effluent concentrations".
In 1998,ANL again updated the MILDOS-AREA code in an attempt to improve the "user
friendliness"of the software.In the past,the user must develop an input file in an American
Standard Code for Information Interchange (ASCII)file containing values that are required by
the code.The code executes this file to produce the output.The latest version of
MILDOS-AREA,has a graphical user interface (OUI)which provides an interface for the user to
input each parameter needed for the calculations in the Windows operating system.The OUI
allows the results of the MILDOS-AREA calculations to be viewed.The 1998 update was the
last time ANL made changes to the MILDOS-AREA code.The most up-to-date version of
MILDOS-AREA was used in this assessment.
MILDOS-AREA calculates the impacts based on annual average air concentrations of nuclides
considered.The human pathways considered in MILDOS-AREA for individual and population
impacts are:inhalation,extemal exposure from ground concentrations,extemal exposure from
cloud immersion,ingestion ofvegetables,ingestion ofmeat and ingestion ofmilk.
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APPENDIXB
EMISSION CALCULATIONS
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APPENDIXB EMISSION CALCULATIONS
Supplemental Infonnation which describes the model and assumptions used to calculate the
source emissions for the sources described in Section 4.0 are provided below.
B.l CALCULATION OF ANNUAL DUST Loss
The calculation of the annual dust loss from the ore pads and the tailings cells was required to
calculate an emission factor.This dusting rate for the tailings impoundments is calculated
according to the emission factor (Ew)equation from NRC Regulatory Guide 3.59 (NRC 1987).
The equation offor the dusting rate is calculated as follows:
where,
E =3.156x107 x "R F
w 0.5 7 s s
(B.I)
Ew=annual dust loss per unit area in glm2yr;
Fs=annual average frequency of occurrence of wind speed group S (dimensionless)obtained
from the joint relative frequency disttibution for the mill (provided by DUSA (Turk 2007b));
Rs=resuspension rate for the tailings pond at the average wind speed for wind group S,for
particles :s 20 11m in diameter in glm2s;
3.156 x 107=number of seconds per year;and,
0.5=fraction ofthe total dust lost constituted by particle :s 20 11m in diameter.
TABLE B.l
PARAMETER VALUES FOR CALCULATION OF ANNUAL DUSTING RATE FOR
EXPOSED TAILINGS
Average Wind
Frequency
Wind Speed (kts)Resuspension of Rs xFsSpeedRate(Rs)Occurrence,
III/m's)"IFs)b
oto 3 I.5 0 0.165 O.OOE+OO
4 to 6 5.5 0 0.427 O.OOE+OO
7 to 10 10.0 3.92E-07 0.276 1.08E-07
II to 16 15.5 9.68E-06 0.106 I.03E-06
17t021 21.5 5.71E-05 0.021 1.20E-06
21+28.0 2.08E-04 0,005 1.04E-06f----,
Is 3.37E-06
Notes:
a)Resuspension rate ofa function ofwind speed is computed by the MILDOS code.
b)Wind speed frequency obtained from joint frequency distribution data provided by DUSA (Turk 2007b).
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Using equation 8.1 and the parameters in Table B-1,the annual dust loss from the tailings cells
is approximately 213 glm2yr.As mentioned in Section 4.2.1,the annual dust lost for ore pads is
10%of that of the tailings cells since the paliiculates on the ore pad are coarse material (1 to 6
inch)because the ore has not yet been ground;therefore the annual dust loss from the ore pad is
21.29 glm\T.
B.2 EMISSION CALCULATIONS
The equations and assumptions used to calculate the radioactive particulate (U-238)and its
daughters thorium (Th-230),radium (Ra-226)and lead (Pb-210))and radon emission rates from
the grizzly,grinding,ore pads,vanadium stack (exclusively for processing Colorado Plateau
ore),yellowcake stacks (nOlih and south yellowcake stacks)and the tailings cells were taken
from NRC Regulatory Guide 3.59 (NRC 1987),NUREG-0706 (NRC 1980)and the EnecoTech
analysis (EnecoTech 1991a and 1991b).
8.2.1 Wet Grinding
Radioactive Particulate Emissiofl Rates
Colorado Plateau Arizona Strip
Ore Ore
Process Rate (tpy)730,000 730,000
Coulamiuant Concentration (pCi/g U-238)700 1783
Process Emission Factor (lbs/ton)'0.16 0.16
Activity Enrichment Ratio 2.5 2.5
Control Factor (%)"99.90 99.90
Notes:
a)For moisture <8%(NRC 1987).
b)Particulate emission control from the wet grinding operations was assumed to be 99.9%(EnecoTech 1991a and
1999b)
The U-238 Emission Rate (S)is calculated as follows:
S=(Process Rate (tons/yr))*(Process
(453.6 gllb)*(Contaminant Concentration
(I-Control Factor)*(l0-12 CilpCi)
Emission Factor (lbs/ton))*
(pCi/g))*(Activity Enrichment Ratio)*
(8.2-1 )
Using equation 8.2-1,the U-238 Emission Rate from wet grinding operations of Colorado
Plateau ore is approximately 9.27E-05 Ci/yr.U-238 decay daughters (Th-230,Ra-226 and
Pb-21 0)are assumed to be in secular equilibrium;therefore the decay daughters are also emitted
at a rate of9.27E-05 Ci/yr.Similarly,the U-238 Emission Rate from the wet grinding operations
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of Arizona Strip ore is approximately 2.36E-04 Cilyr and the decay daughters (Th-230,Ra-226
and Pb-2l 0)are also emitted at a rate of 2.36E-04 Ci/yr.
Radon Emission Rates
Colorado Arizona
l)lateau ore Strip ore
Process Rate (tpy)730,000 730,000
Contaminant Concentration 700 1783(pCi/g Ra-226)
Activity Factor(%)'20 20
Note:
a)It was assumed that only 20%ofthe radon is available for release or emanation from the mineral grains in
which it is produced (i.e.the emanating fraction or power is 0.20)(NRC 1980).
Radon Release (F):
F=(Process Rate (tons/yr»*(2000 Ibs/ton)*(453.6 gllb)*
(Contaminant Concentration pCi/g Ra-226)*(l 0-12 Ci/pCi)*(Activity Factor)(8.2-2)
Using equation 8.2-2,the radon release from the wet grinding operations of Colorado Plateau
ore is approximately 92.7 Ci/yr.Similarly,the radon release from the wet grinding operations of
Arizona Strip ore is approximately 236 Ci/yr.
8.2.2 Ore Dump to Grizzly
Radioactive Particulate Emission Rates
-Colorado Plateau Arizona Strip
Ore Ore
Process Rate (tpy)730,000 730,000
Contaminant Concentration (pCi/g U-238)700 1783
Process Emission Factor (Ibs/ton)'0.16 0.16
Activity Enrichment Ratio 2.5 2.5
Control Factor (%)99.90 99.90
Notes:
a)For moisture <8%(NRC 1987).
b)Grizzly Dump is enclosed on three sides.Trucks dump inside enclosure under negative pressure.The 1D fans
are ducted through a baghouse.Ore moisture content is 10 %(EnecoTech 1991a and 1999b).
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The U-238 Emission Rate (S)is calculated as follows:
S=(Process
(Contaminant
(10-12 Ci/pCi)
Rate (tons/yr))*(Process Emission Factor
Concentration (pCi/g))*(Activity Enrichment
(lbs/ton))*(453.6 gllb)*
Ratio)*(l-Control Factor)*
(8.2-3)
Using equation 8.2-3,the U-238 Emission Rate due to the trucks dumping Colorado Plateau ore
on the grizzly is approximately 9.27E-05 Ci/yr.U-238 decay daughters (Th-230,Ra-226 and
Pb-210)are assumed to be in secular equilibrium;therefore the decay daughters are also emitted
at a rate of 9.27E-05 Ci/yr.Similarly,the U-238 Emission Rate due to the trucks dumping
Arizona Strip ore on the grizzly is approximately 2.36E-04 Ci/yr and the decay daughters
(Th-230,Ra-226 and Pb-210)are also emitted at a rate of2.36E-04 Ci/yr.
Radon Emission Rates
No radon is released from the trucks dumping ore onto the grizzly.
B.2.3 Yellowcake Stacks
As mentioned in Section 4.1.3,the mill has two yellowcake dryers (north and south yellowcake
stack dryers);therefore the total emissions were assumed to be divided equally between the two
stacks (i.e.,north and south yellowcake stacks).
Radioactive Particulate Emission Rates
Colorado Plateau Arizoua Strip
Ore Ore --Process Rate (tpy U3OS)1716 4371
Coutaminant Conceutration (Ci/g ofU-238)3.33E-07 3.33E-07
Process Emission Factor (g U-238/g U3OS)0.848 0.848
Emission Rate (Ibs/ton)'0.092 0.092
Note:
a)Based stack tests that showed an emission rate of0.06 lbs/hr U308 per 1300 lbs/hr process rate which translates
to 0.092 lb/ton including controls (EuecoTech 1991a and 1999b).
The U-238 Emission Rate (S)for one yellowcake stack is calculated as follows:
S=[(Process Rate (tons/yr U30s))*(Emission Rate (lbs/ton))*(Process Emission
(453.6 gllb)*(Contaminant Concentration (Ci/g))]/2
Factor)*
(8.2-4)
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Proposed Development ofNew Tailings Cell 4Bfor White Mesa Uranium Mill
Based on field measurements,the decay daughters Th-230,Ra-226 and Pb-210 are processed
along with yellowcake at 0.22%,0.13%and 0.78%,respectively.
Using equation B.2-4,the U-238 Emission Rate from each yellowcake stack (north and south
yellowcake stacks)is approximately 1.01E-02 Cilyr for the processing of Colorado Plateau ore.
The emission rate for the decay daughters Th-230,Ra-226 and Pb-210 is 2.22E-05,
1.31 E-05 and 7.88E-05 Ci/yr,respectively from each yellowcake stack (nolth and south
yellowcake stacks).Similarly,the U-238 Emission Rate from each yellowcake stack (north and
south yellowcake stacks)is approximately 2.58E-02 Ci/yr for the processing of Arizona Strip
ore.The emission rate for the decay daughters Th-230,Ra-226 and Pb-210 is 5.67E-05,
3.35E-05 and 2.0IE-04 Ci/yr,respectively from each yellowcake stack (north and south
yellowcake stacks).
Radon Emission Rates
There is no significant radon releases during this process.
B.2.4 Vanadium Stack
Radioactive Particulate Emission Rates
As mentioned in Section 4.1.4,the vanadium source was only used in the MILDOS-AREA
model for Colorado Plateau ore.The product from the vanadium recovery contains less than
0.005%U308 (NRC 1980).Therefore,the emission rates ofU-238 and its decay daughters from
the vanadium stack were assumed to be 0.005%of the total emission rate from the yellowcake
stacks (north and south yellowcake stacks).
Emission Rate (S)(Ci/yr)
Radioactive Particnlate Total from
Yellowcake Vanadium Stacka
Stacks
D-238 2.02E-02 1.01E-06
Th-230 4.45E-05 2.22E-09
Ra-226 2.63E-05 1.31E-09
Pb-2l0 1.58E-04 7.88E-09
Note:
a)Total from yellowcake stacks (north and sonth yellowcake stacks)*0.005%.
Radon Emission Rates
There are no significant radon releases during this process.
34489-10-FINAL-April 2008 B-5 SENES Consultants Limited
Proposed Development ofNew Tailings Ce1l4Bfor White Mesa Uranium Mill
B.2.5 Ore Pads
The ore pad storage operation has two different sources of emissions -namely unloading from
the truck to the ore pad and wind emissions.For the wind emissions calculated,it was assumed
that approximately 300,000 tons of ore are temporarily stockpiled with a height of 30 ft (9.1 m).
and bulk density of ore of 120 Ibs/ftJ (1.47 tons/yd\Using these assumptions,the area of the
ore pad is approximately 17,000 m2
Radioactive Particulate Emission Rates
Source Description:TlUck Unloading
Colorado Plateau Arizoua Strip
Ore Ore-Process Rate (tpy)730,000 730,000
Contaminant Concentration (pCi/g U-238)700 1783
Process Emission Factor (ibs/yd3)'0.04 0.04
Activity Emission Ratio 2.5 2.5
Control Factor None None
Bulk Density ofOre (tons/yd3)1.47 1.47
Note:
a)Process emission factor for Truck end dump (NRC 1987).
The U-238 Emission Rate (S)is calculated as follows:
S=(Process Rate (tons/yr»*(l
(Process Emission Factor (lbs/ydJ»*(453.6 g/Ib)*(Contaminant
(Activity Enrichment Ratio)*(l 0-12 CilpCi)
ydJ/1.47
Concentration
tons)*
(pCi/g»*
(B.2-5)
Using equation B.2-5,the U-238 Emission Rate from huck unloading Colorado Plateau ore is
approximately 1.58E-02 Ci/yr.U-238 decay daughters (Th-230,Ra-226 and Pb-21 0)were
assumed to be in secular equilibrium;therefore the decay daughters are also emitted at a rate of
1.58E-02 Ci/yr.Similarly,the U-238 Emission Rate from tlUck unloading of Arizona Strip ore is
approximately 4.02E-02 Ci/yr and the decay daughters (Th-230,Ra-226 and Pb-210)are also
emitted at a rate of4.02E-02 Ci/yr.
34489-10 -FINAL -April 2008 8-6 SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4B for Whit~Mesa Uranium Mill
Source Description:Wind Erosion
Colorado Plateau Arizoua Strip
Ore Ore
Area (m')'17000 17000 --
Contaminant Concentration (pCi/g U-238)700 1783
Process Emission Factor,Ew (g/m'yr)b 21.29 21.29
Activity Enrichment Ratio 2.5 2.5
Control Factor (%)'50 50
Notes:
a)Calculated assuming a stockpile of 300,000 tons of ore with a height of 30 ft.and bulk ore density of
1.47 tons/yd3•
b)The process emission factor for the ore pad was derived in Section B.I.
c)The control factor of 50%is based on the assumption that an active watering program will be in place during
operations (EnecoTech 1991a and 1999b).
The U-238 Emission Rate (S)is calculated as follows:
S=(Process Emission Factor (glm2yr))*(Area (m2))*(Contaminant Concentration
(Activity Enrichment Ratio)*(l-Control Factor)*(l 0-12 CilpCi)
(pCi/g))*
(8.2-6)
Using equation 8.2-6,the U-238 Emission Rate from trucks unloading Colorado Plateau ore is
approximately 3.I7E-04 Ci/yr.U-238 decay daughters (Th-230,Ra-226 and Pb-210)were
assumed to be in secular equilibrium;therefore the decay daughters are also emitted at a rate of
3.17E-04 Ci/yr.Similarly,the U-238 Emission Rate from truck unloading of Arizona Strip ore is
approximately 8.07E-04 Ci/yr and the decay daughters (Th-230,Ra-226 and Pb-210)are also
emitted at a rate of 8.07E-04 Ci/yr.
The total radioactive paliiculate emission rates from the ore pad are obtained by adding the
results of truck unloading and wind erosion and are as follows:
Emission Rate (S)(Ci/yr)
Radioactive Partieulate Colorado Plateau Arizona Strip
Ore Ore
U-238 1.61E-02 4.IOE-02
Th-230 1.61E-02 4.IOE-02
Ra-226 1.61E-02 4.IOE-02
Pb-210 1.61 E-02 4.IOE-02
34489-10 -FINAL-April 2008 B-7 SENES Consultants Limited
Proposed Development o/New Tailings Ce1l4B/or White Mesa Uranium Mill
Radon Emission Rates
Colorado Arizona
Plateau ore Strip ore
Area (m2)17000 17000
Contaminant Concentration 700 1783(PCi/g Ra-226)
Specific Radon Flux Factor
(pCi Rn-222/m2s)/(pCi/g Ra-1 1
226)
Radon Release (F):
F=(Specific Radon Flux Factor (pCi Rn-222/m2s)/(pCi/g Ra-226))*(Contaminant Concentration
(pCi/g Ra-226))*(Area (m2))*(3.156xl07 s/yr)*(l0-12 CilpCi)(8.2-7)
Using equation 8.2-7,the radon release from storage of Colorado Plateau ore is approximately
375 Ci/yr.Similarly,the radon release from storage of Arizona Strip ore is approximately
956 Ci/yr.
8.2-6 Tailings Cells
Factors used to Calculate Radioactive Particulate Emission Rates
Colorado Plateau Ore Arizona Stri(l.9re
Active Active
Cell 3 Cell4AJ4B Cell 3 Ccll4AJ4B
Area (acres)10 10 10 10
Contamiuant Concentration (pCi/g D-42 42 107 107238)'
Contaminant Concentration ofall other 700 700 1783 1783isotopes(pCi/g)
Process Emission Factor,Ew(glm2yr)b 213 213 213 213
Activity Enrichment Ratio 2.5 2.5 2.5 2.5
Control Factor (%)'70 70 70 70
!:'lotes:
a)Assumes 94%recovery.
b)The process emission factor for the tailings cells was derived in Section B.1.
c)The control factor of 70%is based on the assumption that active watering programs as well as crusting agents
are used to minimize the erosion ofthe tailings by wind (EnecoTech 1991a and 1991b).
34489-10·-FINAL·April 2008 B-8 SENES Consultants Limited
Proposed Development o/New Tailings Ce1l4B/or White Mesa Uranium Mill
The Emission Rate (S)for U-238 and its decay daughters were calculated as follows:
S=(Process Emission
(Contaminant Concentration
(10-12 Ci/pCi)
Factor (g/m2yr»*(Area
(pCi/g»*(Activity Enrichment
(acres»*(4047 m2/acre)*
Ratio)*(l-Control Factor)*
(8.2-8)
Using equation 8.2-8,the U-238 Emission Rate from the active tailings cells 3,4A and 48 fi'om
the processing of Colorado Plateau ore is approximately 2.71 E-04 Ci/yr.The decay daughters
(Th-230,Ra-226 and Pb-21 0)are emitted at a rate of4.52E-03 Ci/yr.
Similarly,the U-238 Emission Rate from the active tailings cells 3,4A and 48 fi'om the
processing ofArizona Strip ore is approximately 6.9IE-04 Ci/yr.The decay daughters (Th-230,
Ra-226 and Pb-21 0)are emitted at a rate of 1.15E-02 Ci/yr.
There is no dust released from tailings cells 2 and 3 with interim covers.
Factors Used to Calculate Radon Emission Rates
Colorado Plateaul Arizona Strip Ore
Interim Soil Cover Active
Cell 2 Cell 3 Cell 3 Ce1l4A14B
Area (acres)66.8 70 70 40
Contaminant Concentration 10 10 20 20(pCi/m2s)
Radon Release (F):
F=(Contaminant Concentration (pCi/m2s)*(Area (acres»*(4047
(10.12 Ci/pCi)
m2/acre)*(3.l56xI07 s/yr)*
(8.2-9)
Using equation 8.2-9,the radon release from the active tailings cells 3,4A and 48 are
approximately 179 and 102 Ci/yr,respectively.The radon release for tailings cells 2 and 3 with
interim cover are approximately 85.3 and 89.4 Ci/yr,respectively.
34489~I 0·-FINAL-April 2008 8-9 SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4Bfor White Mesa Uranium Mill
APPENDIXC
MILDOS-AREA RESULTS
34489-10 --FINAL ~April 2008 SENES Consultants Limited
Proposed Development ofNew Tailings Ce1l4B for White Mesa Uranium Mill
APPENDIXC MILDOS-AREA RESULTS
This Appendix provides the dose estimates for MILDOS-AREA runs for the mill area (including
the ore pads)and each tailings cell for the processing of Colorado Plateau or Arizona Strip ore.
The total annual dose commitments and 40 CFR 190 annual dose commitments for Phases I and
2 are provided in Sections C.I and C.2 for Colorado Plateau ore and Arizona Strip ore,
respectively.
C.I MILDOS-AREA RESULTS FOR COLORADO PLATEAU ORE
The MILDOS-AREA calculated total annual dose commitments (including radon)and 40 CFR
190 annual dose commitments for the mill area (including the ore pads)and each tailings cell for
processing ofColorado Plateau ore are provided in Sections C.!.!and C.I.2,respectively.
c.1.1 R313-15-301 (l)(a)Regulatol'y Compliance
TABLE C.l-l
ANNUAL DOSE COMMITMENTS
(COLORADO PLATEAU ORE)
Estimated Dose (mrem/yr)
Location Age Organ Mill Area Interim Soil Cover Active
Gronp (including Tailings Tailings Tailings Tailings Tailings
ore pads)Cell 2 Cell 3 Cell 3 Ce1l4A Ce1l4B
Effective l.i IE+OO 6.03E-02 5.84E-02 l.30E-OI 6.88E-02 5.55E-02
Infant Bone 1.81E+OO 2.57E-03 2.70E-03 6.09E-02 4.94E-02 3.74E-02
Avg.Lung 4.66E-Ol 2.45E-03 2.55E-03 3.46E-02 2.77E-02 2.14E-02
Bronchi 9.22E+OO 9.67E-OI 9.34E-Ol 1.87E+OO 9.14E-OI 7.44E-Ol
Effective 7.96E-OI 6.03E-02 5.84E-02 1.29E-OI 6.77E-02 5.46E-02
Child Bone 1.24E+OO 2.65E-03 2.79E-03 7.48E-02 6.06E-02 4.54E-02
Nearest Avg.Lung 6.20E-OI 2.56E-03 2.69E-03 4.86E-02 3.88E-02 2.92E-02
Potential Bronchi 9.22E+OO 9.67E-OI 9.34E-OI 1.87E+OO 9.14E-Ol 7.44E-OI
Resident Effective 8.34E-Ol 6.04E-02 5.85E-02 l.32E-OI 7.05E-02 5.66E-02
(BHV-I)Bone 4.40E+OO 3.28E-03 3.53E-03 2.42E-OI 1.98E-OI 1.46E-OlTeenage~g.Lung 4.94E-OI 2.54E-03 2.66E-03 3.99E-02 3.I5E-02 2.38E-02
Bronchi 9.22E+OO 9.67E-OI 9.34E-OI 1.87E+OO 9.14E-OI 7.44E-OI
Effective 7.30E-O I 6.03E-02 5.84E-02 1.27E-OI 6.59E-02 5.32E-02
Adult Bone 1.9 1E+OO 2.85E-03 3.03E-03 1.20E-Ol 9.80E-02 7.29E-02
Avg.Lung 3.43E-O I 2.50E-03 2.6IE-03 2.88E-02 2.25E-02 l.70E-02
Bronchi 9.22E+OO 9.67E-O I 9.34E-OI 1.87E+OO 9.14E-Ol 7.44E-OI
34489~10 .,.FINAL -April 2008 C-I SENES Consultants Limited
Proposed Development ofNew Tailings Ce1l4B for White Mesa Uranium Mill
TABLE C.l-l (Cont'd)
ANNUAL DOSE COMMITMENTS
(COLORADO PLATEAU ORE)
Estimated Dose (mrem/yr)
Location Age Organ Mill Area Interim Soil Cover Active
Group (including Tailings Tailings Tailings Tailings Tailings
ore pads)Cell 2 Cell 3 Cell 3 Cell4A Cell4B
Effective 2.18E-Ol 2.14E-02 2.09E-02 4.54E-02 2.53E-02 2.42E-02
Infant Bone 2.69E-Ol l.84E-03 l.90E-03 l.88E-02 1.55E-02 1.53E-02---
Avg.Lung 8.29E-02 1.61E-03 l.65E-03 I.l7E-02 9.36E-03 9.18E-03
Bronchi 2.20E+OO 3.31E-Ol 3.22E-OI 6.43E-OI 3.39E-O1 3.23E-O1
Effective l.75E-Ol 2.14E-02 2.08E-02 4.48E-02 2.49E-02 2.37E-02
Child Bonc l.91E-OI l.97E-03 2.04E-03 2.20E-02 1.82E-02 1.80E-02
Nearest Avg.L~l.OlE-Ol l.82E-03 l.87E-03 l.48E-02 I.l9E-02 I.l7E-02
Historical Bronchi 2.20E+OO 3.31E-OI 3.22E-OI 6.43E-OI 3.39E-O1 3.23E-OI
Residcnt Effective l.80E-Ol 2.14E-02 2.09E-02 4.57E-02 2.57E-02 2.44E-02
(BHV-2)Bone 6.40E-Ol 3.10E-03 3.28E-03 6.48E-02 5.52E-02 5.52E-02TeenageAvg.Lung 8.09E-02 l.78E-03 1.83E-03 l.23E-02 9.7IE-03 9.60E-03
Bronchi 2.20E+OO 3.31E-Ol 3.22E-OI 6.43E-OI 3.39E-Ol 3.23E-O1
Effective l.65E-Ol 2.14E-02 2.08E-02 4.43E-02 2.44E-02 2.33E-02
Adult Bone 2.89E-OI 2.34E-03 2.45E-03 3.38E-02 2.84E-02 2.82E-02
Avg.Lung 5.86E-02 l.70E-03 l.74E-03 9.44E-03 7.2IE-03 7.10E-03
Bronchi 2.20E+OO 3.3lE-OI 3.22E-OI 6.43E-OI 3.39E-Ol 3.23E-OI
Effective 6.83E-Ol 4.54E-02 4.33E-02 9.67E-02 5.23E-02 4.57E-02
Infant Bone l.05E+OO 2.46E-03 2.54E-03 4.45E-02 3.6IE-02 3.10E-02
Avg.Lung 2.68E-Ol 2.30E-03 2.36E-03 2.59E-02 2.07E-02 l.79E-02
Bronchi 5.98E+OO 7.20E-OI 6.84E-O1 l.38E+OO 6.95E-Ol 6.09E-Ol
Effective 5.03E-Ol 4.54E-02 4.33E-02 9.57E-02 5.14E-02 4.49E-02
Child Bone 7.12E-Ol 2.55E-03 2.65E-03 5.38E-02 4.37E-02 3.74E-02
Avg.Lung 3.56E-Ol 2.44E-03 2.53E-03 3.52E-02 2.8IE-02 2.41E-02
Nearest Bronchi 5.98E+OO 7.20E-Ol 6.84E-OI l.38E+OO 6.95E-Ol 6.09E-O1ActualEffective5.24E-Ol 4.54E-02 4.34E-02 9.81 E-02 5.34E-02 4.66E-02Resident------
Teenage Bone 2.52E+OO 3.36E-03 3.58E-03 l.70E-OI l.40E-Ol I.l9E-Ol
Avg.Lung 2.85E-Ol 2.41E-03 2.50E-03 2.90E-02 2.29E-02 l.96E-02
Bronchi 5.98E+OO 7.20E-Ol 6.84E-OI l.38E+OO 6.95E-Ol 6.09E-OI
Effective 4.65E-Ol 4.54E-02 4.33E-02 9.4IE-02 5.0IE-02 4.38E-02
Adult Bone I.lOE+OO 2.8IE-03 2.95E-03 8.54E-02 6.99E-02 5.96E-02
Avo.Lung 2.00E-Ol 2.36E-03 2.43E-03 2.13E-02 l.65E-02 l.41E-02
Bronchi 5.98E+OO 7.20E-OI 6.84E-OI l.38E+OO 6.95E-Ol 6.09E-OI
34489-10-FINAL -April 2008 C-2 SENES Consultants Limited
Proposed Development ofNew Tailings Ce1l4B for White Mesa Uranium Mill
TABLE C.l-l (Cont'd)
ANNUAL DOSE COMMITMENTS
(COLORADO PLATEAU ORE)
Estimated Dose (mremlyr)
Location Age Organ Mill Area Interim Soil Covel'Active
Group (including Tailings Tailings Tailings Tailings Tailiugs
ore pads)Cell 2 Cell 3 Cell 3 Cell4A Cell4B--~(lE-OIEffective 2.23E-02 2.48E-02 5.17E-02 3.15E-02 2.82E-02
Iufant Bone 1.16E-OJ 2.8IE-03 3.05E-03 1.44E-02 1.22E-02 l.08E-02
Avg.Lung 4.60E-02 2.26E-03 2.47E-03 l.04E-02 8.6IE-03 7.61E-03
Bronchi 1.65E+OO 3.36E-OI 3.74E-OI 7.48E-Ol 4.43E-Ol 3.97E-OI
Effective 1.21E-Ol 2.23E-02 2.48E-02 5.11E-02 3.09E-02 2.77E-02-----_._--------
Child Bone 7.67E-02 3.14E-03 3.38E-03 1.51 E-02 1.27E-02 1.12E-02
Avg.Lung 4.24E-02 2.76E-03 2.99E-03 l.09E-02 8.64E-03 7.69E-03-
White Mesa Bronchi 1.65E+OO 3.36E-OI 3.74E-OI 7.48E-OI 4.43E-Ol 3.97E-Ol
Community Effective 1.21E-OI 2.24E-02 2.49E-02 5.13E-02 3.10E-02 2.79E-02
Teenage Bone 2.15E-OI 5.93E-03 6.28E-03 3.51E-02 3.09E-02 2.72E-02
Avg.Lung 3.35E-02 2.67E-03 2.90E-03 9.33E-03 7.10E-03 6.34E-03
Bronchi 1.65E+OO 3.36E-Ol 3.74E-OI 7.48E-OI 4.43E-OI 3.97E-Ol
Effective 1.17E-OI 2.23E-02 2.48E-02 5.07E-02 3.05E-02 2.73E-02
Adult Bone l.06E-OI 4.04E-03 4.33E-03 2.08E-02 1.78E-02 1.57E-02
Avg.Lung 2.66E-02 2.47E-03 2.69E-03 7.88E-03 5.77E-03 5.18E-03
Bronchi 1.65E+OO 3.36E-OI 3.74E-Ol 7.48E-OI 4.43E-OI 3.97E-Ol
Effective 6.98E-02 8.36E-03 8.50E-03 1.82E-02 l.05E-02 l.04E-02
Infant Bone 7.53E-02 1.17E-03 1.22E-03 7.12E-03 5.86E-03 5.93E-03
Avg.Lnng 2.45E-02 8.95E-04 9.22E-04 4.57E-03 3.64E-03 3.67E-03
Bronchi 7.34E-OI l.25E-OI 1.27E-Ol 2.53E-O I 1.40E-OI l.38E-OI
Effective 5.72E-02 8.34E-03 8.49E-03 1.79E-02 1.03E-02 l.02E-02
Child Bone 5.16E-02 l.34E-03 l.39E-03 8.18E-03 6.75E-03 6.83E-O~_
.!':."_g~!:lll1g_2.78E-02 U5E-03 1.19E-03 5.69E-03 4.5IE-03 4.55E-03--.
Blanding Bronchi 7.34E-Ol 1.25E-OI 1.27E-OI 2.53E-Ol 1.40E-O I l.38E-OJ
Effective 5.84E-02 8.37E-03 8.52E-03 1.82E-02 l.06E-02 l.04E-02
Teenage Bone 1.65E-OI 2.74E-03 2.88E-03 2.28E-02 1.96E-02 1.99E-02
Avg.Lung 2.26E-02 U OE-03 1.14E-03 4.84E-03 3.74E-03 3.76E-03
Bronchi 7.34E-OI 1.25E-Ol l.27E-OI 2.53E-OI 1.40E-O I l.38E-OJ
Effective 5.46E-02 8.33E-03 8.47E-03 1.77E-02 l.OIE-02 9.99E-03
Adult Bone 7.58E-02 1.79E-03 1.87E-03 1.23E-02 l.03E-02 l.05E-02
Avg.Lnng 1.70E-02 9.99E-04 l.03E-03 3.84E-03 2.86E-03 2.87E-03
Bronchi 7.34E-OI 1.25E-Ol 1.27E-OJ 2.53E-OI 1.40E-Ol l.38E-OJ
34489-10 -FINAL-April 2008 C-3 SENES Consultants Limited
Proposed Development o/New Tailings Ce1l4B/or White Mesa Uranium Mill
C.2.2 40 CFR 190 Regulatory Compliance
TABLE C.I-2
40 CFR 190 ANNUAL DOSE COMMITMENTS
(COLORADO PLATEAU ORE)
Estimated Dose (mrem/yr)
Location Age Organ Mill Area Interim Soil Cover Active
Group (including Tailings Tailings Tailings Tailings Tailiugs
ore pads)Cell 2 Cell 3 Cell 3 Cell4A Cell4B
Effective 5,22E-O I O,OOE+OO O,OOE+OO l.24E-02 l.03E-02 7,72E-03
Iufaut Bone l.76E+OO O,OOE+OO O,OOE+OO 5,43E-02 4,54E-02 3,39E-02-
Avg,Luug 4,33E-O I O,OOE+OO O,OOE+OO 2,83E-02 2.38E-02 l.80E-02
Bronchi 9,30E-04 O,OOE+OO O,OOE+OO 2,34E-05 l.93E-05 1,4IE-05
Effective 2,12E-O I O,OOE+OO O,OOE+OO l.lIE-02 9,23E-03 6,83E-03
Child Boue l.20E+OO O,OOE+OO O,OOE+OO 6,80E-02 5,65E-02 4,18E-02
Nearest Avg,Lung 5,85E-O I O,OOE+OO O,OOE+OO 4,19E-02 3,48E-02 2.57E-02
Potential Bronchi 9.30E-04 O,OOE+OO O,OOE+OO 2,34E-05 l.93E-05 1,4IE-05
Resident Effective 2,49E-OI O,OOE+OO O,OOE+OO l.46E-02 l.20E-02 8,86E-03
(BHV-I)Bone 4,37E+OO O,OOE+OO O,OOE+OO 2,34E-OI l.93E-OI l.4IE-OITeenageAvg,Lung 4,6IE-OI O,OOE+OO O,OOE+OO 3,33E-02 2,75E-02 2,03E-02
Bronchi 9.30E-04 O,OOE+OO O,OOE+OO 2,34E-05 l.93E-05 l.4IE-05
Effective l.46E-O I O,OOE+OO O,OOE+OO 8,99E-03 7,44E-03 5,49E-03
Adult Bone l.88E+OO O,OOE+OO O,OOE+OO 1.13E-OI 9,35E-02 6,90E-02
Avg,Lung 3,lOE-O I O,OOE+OO O,OOE+OO 2,24E-02 l.85E-02 l.36E-02
Bronchi 9.30E-04 O,OOE+OO O,OOE+OO 2,34E-05 l.93E-05 l.4IE-05
Effective 7,43E-02 O,OOE+OO O,OOE+OO 3.36E-03 2,99E-03 2,98E-03
Infant Bone 2,54E-OI O,OOE+OO O,OOE+OO l.47E-02 l.31E-02 l.30E-02
Avg,Lung 7,02E-02 O,OOE+OO O,OOE+OO 8,IOE-03 7,28E-03 7,22E-03
Bronchi l.28E-04 O,OOE+OO O,OOE+OO 5,68E-06 5,02E-06 5,04E-06
Effective 3,07E-02 O,OOE+OO O,OOE+OO 2,86E-03 2,53E-03 2,53E-03
Child Bone l.76E-OI O,OOE+OO O,OOE+OO l.76E-02 l.56E-02 l.56E-02
Nearest Avg,Lung 8,70E-02 O,OOE+OO O,OOE+OO l.07E-02 9,54E-03 9,53E-03
Historical Bronchi l.28E-04 O,OOE+OO O,OOE+OO 5,68E-06 5,02E-06 5,04E-06
Resident Effective 3,58E-02 O,OOE+OO O,OOE+OO 3,63E-03 3,22E-03 3,23E-03
(BHV-2)Bone 6,2IE-OI O,OOE+OO O,OOE+OO 5,79E-02 5,12E-02 5,14E-02TeenageAvg,Lung 6,73E-02 O,OOE+OO O,OOE+OO 8.37E-03 7,42E-03 7,43E-03
Bronchi l.28E-04 O,OOE+OO O,OOE+OO 5,68E-06 5,02E-06 5,04E-06
Effective 2,12E-02 O,OOE+OO O,OOE+OO 2,27E-03 2,OIE-03 2,02E-03
Adult Bone 2,72E-OI O,OOE+OO O,OOE+OO 2,85E-02 2,53E-02 2,53E-02
Avg,Lung 4.55E-02 O,OOE+OO O,OOE+OO 5,66E-03 5,OIE-03 5,02E-03
Bronchi l.28E-04 O,OOE+OO O,OOE+OO 5,68E-06 5,02E-06 5,04E-06
34489-10 --FINAL-April 2008 C-4 SENES Consultants Limited
Proposed Development ofNew Tailings Ce1l4B for White Mesa Uranium Mill
TABLE C.1-2 (Coot'd)
40 CFR 190 ANNUAL DOSE COMMITMENTS
(COLORADO PLATEAU ORE)
Estimated Dose (mrem/yr)
Location Age Organ Mill Area Interim Soil Cover Active
Gronp (including Tailings Tailings Tailings Tailings Tailings
ore pads)Cell 2 Cell 3 Cell 3 Cell4A Cell4B
Effective 3.0IE-OI O.OOE+OO O.OOE+OO 8.77E-03 7.42E-03 6.32E-03
Infant Bone 1.02E+OO O.OOE+OO O.OOE+OO 3.85E-02 3.25E-02 2.77E-02
Avg.Lung 2.43E-OI O.OOE+OO O.OOE+OO 2.04E-02 1.74E-02 1.48E-02
Bronchi 5.32E-04 O.OOE+OO O.OOE+OO 1.61E-05 l.35E-05 1.14E-05
Effective 1.21E-OI O.OOE+OO O.OOE+OO 7.79E-03 6.54E-03 5.55E-03
Child Bone 6.85E-OI O.OOE+OO O.OOE+OO 4.77E-02 4.0IE-02 3.4IE-02-~Y.£.Lung 3.30E-OI O.OOE+OO O.OOE+OO 2.93E-02 2.46E-02 2.09E-02
Nearest 5.32E-04 O.OOE+OO O.OOE+OO l.35E-05ActualBronchi1.61E-05 1.14E-05
Resident Effective 1.42E-OI O.OOE+OO O.OOE+OO 1.01E-02 8.46E-03 7.16E-03
Teenage Bone 2.48E+OO O.OOE+OO O.OOE+OO 1.62E-OI l.35E-OI 1.14E-OI
Avg.Lung 2.59E-O I O.OOE+OO O.OOE+OO 2.32E-02 1.94E-02 I.64E-02
Bronchi 5.32E-04 O.OOE+OO O.OOE+OO 1.61E-05 l.35E-05 1.14E-05
Effective 8.31 E-02 O.OOE+OO O.OOE+OO 6.27E-03 5.26E-03 4.45E-03
Adult Bone 1.07E+OO O.OOE+OO O.OOE+OO 7.88E-02 6.60E-02 5.60E-02
Avg.Lung 1.74E-OI O.OOE+OO O.OOE+OO 1.56E-02 l.3IE-02 l.lIE-02-
Bronchi 5.32E-04 O.OOE+OO O.OOE+OO 1.61E-05 l.35E-05 1.14E-05
Effective 2.98E-02 O.OOE+OO O.OOE+OO 1.90E-03 1.98E-03 I.72E-03
Infant Bone 1.02E-OI O.OOE+OO O.OOE+OO 8.2IE-03 8.59E-03 7.4IE-03
Avg.Lung 3.45E-02 O.OOE+OO O.OOE+OO 5.38E-03 5.6IE-03 4.85E-03
Bronchi 3.85E-05 O.OOE+OO O.OOE+OO 1.94E-06 2.05E-06 l.76E-06
Effective 1.04E-02 O.OOE+OO O.OOE+OO l.29E-03 l.36E-03 1.17E-03
Child Bone 6.IIE-02 O.OOE+OO O.OOE+OO 8.25E-03 8.66E-03 7.45E-03
Avg.Lung 2.86E-02 O.OOE+OO O.OOE+OO 4.82E-03 5.07E-03 ~:~~~White Mesa Bronchi 3.85E-05 O.OOE+OO O.OOE+OO 1.94E-06 2.05E-06
Community Effective 1.08E-02 O.OOE+OO O.OOE+OO 1.46E-03 1.53E-03 l.32E-03
Teenage Bone 1.85E-OI O.OOE+OO O.OOE+OO 2.24E-02 2.36E-02 2.03E-02
Avg.Lun[2.0IE-02 O.OOE+OO O.OOE+OO 3.45E-03 3.63E-03 3.12E-03
Bronchi 3.85E-05 O.OOE+OO O.OOE+OO 1.94E-06 2.05E-06 1.76E-06
Effective 6.70E-03 O.OOE+OO O.OOE+OO 9.7 IE-04 1.02E-03 8.78E-04
Adult Bone 8.57E-02 O.OOE+OO O.OOE+OO 1.21E-02 I.27E-02 1.09E-02
Avg.Lung 1.41 E-02 O.OOE+OO O.OOE+OO 2.42E-03 2.54E-03 2.18E-03
Bronchi 3.85E-05 O.OOE+OO O.OOE+OO 1.94E-06 2.05E-06 l.76E-06
34489-10 -FINAL-April 2008 c-s SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4B for White Mesa Uranium Mill
TABLE C.I-2 (Cont'd)
40 CFR 190 ANNUAL DOSE COMMITMENTS
(COLORADO PLATEAU ORE)
Estimated Dose (mrem/yr)
Location Age Organ Mill Area Interim Soil Cover Active
Group (including Tailings Tailings Tailings Tailings Tailiugs
ore pads)Ccll2 Cell 3 Cell 3 Cell4A Cell4B
Effective 2.00E-02 O.OOE+OO O.OOE+OO 1.05E-03 1.01E-03 1.03E-03
Infaut Bone 6.79E-02 O.OOE+OO O.OOE+OO 4.59E-03 4042E-03 4.52E-03-_.__..
Avg.Lung 1.88E-02 O.OOE+OO O.OOE+OO 2.63E-03 2.54E-03 2.58E-03
Bronchi 3.l7E-05 O.OOE+OO O.OOE+OO 1.63E-06 1.56E-06 1.61E-06
Effective 7.55E-03 O.OOE+OO O.OOE+OO 8.57E-04 8.23E-04 8044E-04
Child Bone 4.34E-02 O.OOE+OO O.OOE+OO 5.31E-03 5.09E-03 5.23E-03
Avg.Lung 2.06E-02 O.OOE+OO O.OOE+OO 3.22E-03 3.09E-03 3.17E-03
Blanding Bronchi 3.l7E-05 O.OOE+OO O.OOE+OO 1.63E-06 1.56E-06 1.61E-06
Effective 8049E-03 O.OOE+OO O.OOE+OO 1.07E-03 1.03E-03 1.05E-03
Teenage Bone 1.48E-Ol O.OOE+OO O.OOE+OO 1.69E-02 1.62E-02 1.67E-02
Avg.Lung 1.56E-02 O.OOE+OO O.OOE+OO 2047E-03 2.38E-03 2044E-03
Bronchi 3.l7E-05 O.OOE+OO O.OOE+OO 1.63E-06 1.56E-06 1.61 E-06
Effective 5.05E-03 O.OOE+OO O.OOE+OO 6.77E-04 6049E-04 6.67E-04
Adult Bone 6.50E-02 O.OOE+OO O.OOE+OO 8047E-03 8.13E-03 8.35E-03
Avg.Lung 1.06E-02 O.OOE+OO O.OOE+OO 1.68E-03 1.62E-03 1.66E-03
Bronchi 3.l7E-05 O.OOE+OO O.OOE+OO 1.63E-06 1.56E-06 1.61 E-06
34489-10 -FINAL -April 2008 C-6 SENES Consultants Limited
Proposed Development ofNew Tailings Cell4B for White Mesa Uranium Mill
C.2 MILDOS-AREA RESULTS FOR ARIZONA STRIP ORE
The MILDOS-AREA calculated total annual dose commitments (including radon)and 40 CFR
190 annual dose commitments for the mill area (including the are pads)and each tailings cell for
processing ofArizona Strip are are provided in Sections C.2.]and C.2.2,respectively.
C.2.I R313-IS-30I (I)(a)Regulatory Compliance
TABLE C.2-I
ANNUAL DOSE COMMITMENTS
(ARIZONA STRIP ORE)
Estimated Dose (ml'em/yr)
Location Age Organ Mill Area Interim Soil Cover Active
Group (iucluding Tailings Tailings Tailings Tailings Tailings
ore pads)Cell 2 Cell 3 Cell 3 Cell4A Cell4B
Effective 2.82E+OO 6.03E-02 5.84E-02 1.52E-OI 8.64E-02 6.86E-02
Infant Bone 4.59E+OO 2.57E-03 2.70E-03 1.47E-OI 1.21E-OI 9.IIE-02
Avg.Lung 1.19E+OO 2.45E-03 2.55E-03 8.04E-02 6.62E-02 5.04E-02
Bronchi 2.35E+OI 9.67E-OI 9.34E-OI 1.87E+OO 9.15E-OI 7.45E-OI
Effective 2.03E+OO 6.03E-02 5.84E-02 1.48E-OI 8.36E-02 6.63E-02
Child Bone 3.15E+OO 2.65E-03 2.79E-03 1.82E-O I 1.50E-OI 1.11 E-OI
Nearest Avg.Lung 1.57E+OO 2.56E-03 2.69E-03 1.16E-OI 9.42E-02 7.02E-02
Potential Bronchi 2.35E+OI 9.67E-OI 9.34E-OI 1.87E+OO 9.15E-OI 7.45E-OI
Resident Effective 2.12E+OO 6.04E-02 5.85E-02 1.57E-OI 9.07E-02 7.15E-02
(BHV-I)Bone 1.12E+OI 3.28E-03 3.53E-03 6.05E-OI 4.97E-OI 3.67E-OITeenageAvg.Lung 1.26E+OO 2.54E-03 2.66E-03 9.34E-02 7.57E-02 5.63E-02
Bronchi 2.35E+OI 9.67E-OI 9.34E-OI 1.87E+OO 9.15E-OI 7.45E-OI
Effective 1.86E+OO 6.03E-02 5.84E-02 1.43E-OI 7.90E-02 6.29E-02
Adult Bone 4.88E+OO 2.85E-03 3.03E-03 2.97E-OI 2.44E-OI 1.8IE-OI
Avg.Lnng 8.74E-OI 2.50E-03 2.6IE-03 6.54E-02 5.27E-02 3.94E-02--
Bronchi 2.35E+OI 9.67E-OI 9.34E-OI 1.87E+OO 9.15E-OI 7.45E-OI
34489-10-FINAL -April 2008 C-7 SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4B for White Mesa Uranium Mill
TABLE C.2-1 (Cont'd)
ANNUAL DOSE COMMITMENTS
(ARIZONA STRIP ORE)
Estimated Dose (mrem/yr)
Location Age Organ Mill Area Interim Soil Cover Active
Group (including Tailings Tailings Tailings Tailings Tailings
ore pads)CeU 2 CeU3 CeU3 CeU4A CeU4B
Effective 5.57E-OI 2.14E-02 2.09E-02 5.10E-02 3.04E-02 2.93E-02._--
Infant Bone 6.85E-OI l.84E-03 l.90E-03 4.19E-02 3.62E-02 3.59E-02-
Avg.Lung 2.11E-OI l.6IE-03 l.65E-03 2.47E-02 2.IOE-02 2.07E-02
Bronchi 5.6IE+OO 3.3IE-OI 3.22E-OI 6.44E-OI 3.39E-O I 3.23E-OI
Effective 4.45E-OI 2.14E-02 2.08E-02 4.98E-02 2.92E-02 2.8IE-02
Child Bone 4.85E-OI l.97E-03 2.04E-03 4.96E-02 4.28E-02 4.25E-02
Nearest Avg.Lung 2.56E-OI l.82E-03 l.87E-03 3.18E-02 2.7IE-02 2.69E-02
Historical Bronchi 5.6IE+OO 3.3IE-OI 3.22E-OI 6.44E-OI 3.39E-OI 3.23E-OI
Resident Effective 4.59E-O I 2.14E-02 2.09E-02 5.18E-02 3.10E-02 2.99E-02
(BHV-2)Bone l.63E+OO 3.10E-03 3.28E-03 l.54E-OI l.35E-OI l.35E-O ITeenageAVQ.Lung 2.05E-OI l.78E-03 l.83E-03 2.58E-02 2.16E-02 2.15E-02
Bronchi 5.6IE+OO 3.3IE-OI 3.22E-OI 6.44E-OI 3.39E-OI 3.23E-O I
Effective 4.2IE-OI 2.14E-02 2.08E-02 4.83E-02 2.79E-02 2.68E-02
Adult Boue 7.36E-OI 2.34E-03 2.45E-03 7.84E-02 6.79E-02 6.78E-02
AVQ.Lun£...l.49E-OI l.70E-03 l.74E-03 l.87E-02 l.54E-02 l.53E-02
Bronchi 5.6IE+OO 3.3IE-OI 3.22E-OI 6.44E-OI 3.39E-OI 3.23E-OI
Effective l.74E+OO 4.54E-02 4.33E-02 l.l2E-O I 6.49E-02 5.64E-02
Infant Bone 2.67E+OO 2.46E-03 2.54E-03 l.05E-OI 8.77E-02 7.48E-02
Avg.Lung 6.82E-OI 2.30E-03 2.36E-03 5.88E-02 4.87E-02 4.18E-02
Bronchi l.53E+OI 7.20E-OI 6.84E-O I l.38E+OO 6.96E-OI 6.IOE-OI
Effective l.28E+OO 4.54E-02 4.33E-02 l.09E-OI 6.26E-02 5.44E-02
Child Bone l.8IE+OO 2.55E-03 2.65E-03 l.29E-OI l.07E-OI 9.09E-02
Avg.Lung 9.05E-OI 2.44E-03 2.53E-03 8.18E-02 6.73E-02 5.73E-02
Nearest Bronchi l.53E+OI 7.20E-OI 6.84E-OI l.38E+OO 6.96E-OI 6.10E-OIActual.
Resident Effective l.34E+OO 4.54E-02 4.34E-02 l.l5E-OI 6.77E-02 5.86E-02
Teenage Bone 6.40E+OO 3.36E-03 3.58E-03 4.2IE-OI 3.50E-O I 2.97E-OI
AVQ.Lung 7.27E-OI 2.4IE-03 2.50E-03 6.62E-02 5.40E-02 4.60E-02
Bronchi l.53E+OI 7.20E-OI 6.84E-OI l.38E+OO 6.96E-OI 6.10E-OI
Effective l.l9E+OO 4.54E-02 4.33E-02 l.05E-OI 5.94E-02 5.17E-02
Adult Bone 2.80E+OO 2.8IE-03 2.95E-03 2.08E-OI l.73E-OI l.47E-OI
AVQ.Lung 5.09E-OI 2.36E-03 2.43E-03 4.67E-02 3.78E-02 3.23E-02
Bronchi l.53E+OI 7.20E-OI 6.84E-OI l.38E+OO 6.96E-OI 6.lOE-OI
34489~IO -FINAL·April 2008 C-8 SENES Consultants Limited
Proposed Development ofNew Tailings Cell4Bfor White Mesa Uranium Mill
TABLE C.2-1 (Cont'd)
ANNUAL DOSE COMMITMENTS
(ARIZONA STRIP ORE)
Estimated Dose (mrem/yr)
Location Age Organ Mill Area Interim Soil Cover Active
Group (including Tailings Tailings Tailings Tailings Tailings
ore pads)Cell 2 Cell 3 Cell 3 Cell4A Cell4B
Effective 3.56E-OI 2.23E-02 2048E-02 5047E-02 3047E-02 3.IOE-02-
Infant Bone 2.95E-OJ 2.8IE-03 3.05E-03 2.73E-02 2.57E-02 2.24E-02
Avg.Lung l.l7E-OJ 2.26E-03 2047E-03 1.89E-02 I.74E-02 1.53E-02
Bronchi 4.20E+OO 3.36E-OI 3.74E-OI 7o48E-OI 4o43E-OI 3.97E-O I
Effective 3.07E-OI 2.23E-02 2048E-02 5.32E-02 3.32E-02 2.96E-02----
Child Bone 1.96E-OI 3.14E-03 3.38E-03 2.80E-02 2.63E-02 2.29E-02
Avg.Lung 1.08E-OI 2.76E-03 2.99E-03 1.85E-02 1.66E-02 1.46E-02
White Mesa Bronchi 4.20E+OO 3.36E-OJ 3.74E-OJ 7o48E-O\4o43E-OI 3.97E-OI
Community Effective 3.09E-OJ 2.24E-02 2049E-02 5.37E-02 3.36E-02 3.00E-02
Teenage Bone 5o46E-OI 5.93E-03 6.28E-03 6.98E-02 6.76E-02 5.87E-02
Avg.Lung 8.54E-02 2.67E-03 2.90E-03 1.48E-02 1.29E-02 l.l3E-02
Bronchi 4.20E+OO 3.36E-OI 3.74E-OI 7o48E-OI 4o43E-O\3.97E-OI
Effective 2.97E-OI 2.23E-02 2048E-02 5.23E-02 3.22E-02 2.88E-02
Adult Bone 2.70E-OI 4.04E-03 4.33E-03 3.96E-02 3.76E-02 3.27E-02
Avg.Lung 6.77E-02 2047E-03 2.69E-03 l.l8E-02 9.87E-03 8.70E-03
Bronchi 4.20E+OO 3.36E-O\3.74E-O\7o48E-O I 4o43E-OI 3.97E-OI
Effective 1.78E-OI 8.36E-03 8.50E-03 1.99E-02 1.22E-02 1.21 E-02
Infant Bone 1.92E-O I l.l7E-03 1.22E-03 1.43E-02 1.28E-02 1.30E-02
Avg.Lung 6.25E-02 8.95E-04 9.22E-04 8.79E-03 7.70E-03 7.80E-03
Bronchi 1.87E+OO 1.25E-OI 1.27E-OI 2.53E-OI 1.40E-O\1.38E-O\
Effective 1.46E-OI 8.34E-03 8049E-03 1.94E-02 l.l7E-02 l.l6E-02-
Child Bone 1.3\E-OI 1.34E-03 1.39E-03 1.65E-02 1.48E-02 1.51E-02
Avg.Lung 7.09E-02 l.l5E-03 l.l9E-03 I.08E-02 9.42E-03 9.59E-03
Blanding Bronchi 1.87E+OO 1.25E-O\1.27E-O I 2.53E-OI 1.40E-OI 1.38E-OI
Effective 1.49E-OI 8.37E-03 8.52E-03 2.00E-02 1.23E-02 1.22E-02
Teenage Bone 4.19E-O\2.74E-03 2.88E-03 4.92E-02 4049E-02 4.60E-02
Avg.Lung 5.74E-02 l.lOE-03 l.l4E-03 8.8\E-03 7.54E-03 7.67E-03
Bronchi 1.87E+OO 1.25E-OI l.27E-OI 2.53E-OI 1.40E-OI 1.38E-OJ
Effective 1.40E-OI 8.33E-03 8047E-03 1.89E-02 l.l3E-02 l.l2E-02
Adult Bone 1.93E-OI I.79E-03 1.87E-03 2.56E-02 2.3\E-02 2.35E-02
Avg.Lung 4.34E-02 9.99E-04 I.03E-03 6.58E-03 5048E-03 5.56E-03
Bronchi 1.87E+OO 1.25E-OI 1.27E-O\2.53E-OI 1.40E-OI 1.38E-OI
34489-10 -FINAL-April 2008 C-9 SENES Consultants Limited
Proposed Development ofNew Tailings Ce!'4Bfor White Mesa Uranium Mill
C.2.2 40 CFR 190 Regulatory Compliance
TABLE C.2-2
40 CFR 190 ANNUAL DOSE COMMITMENTS
(ARIZONA STRIP ORE)
Estimated Dose (mrem/yr)
Location Age Organ Mill Area Interim Soil Cover Active
Group -(including Tailings Tailings Tailings Tailings Tailings
ore pads)Cell 2 Cell 3 Cell 3 Ce1l4A Ce1l4B
Effective l.33E+OO O.OOE+OO O.OOE+OO 3.15E-02 2.63E-02 1.97E-02
Infant Bone 4.5IE+OO O.OOE+OO O.OOE+OO l.38E-OI 1.16E-OI 8.63E-02
Avg.Lnng 1.10E+OO O.OOE+OO O.OOE+OO 7.22E-02 6.07E-02 4.59E-02
Bronchi 2.37E-03 O.OOE+OO O.OOE+OO 5.96E-05 4.90E-05 3.59E-05
Effective 5.40E-OI O.OOE+OO O.OOE+OO 2.84E-02 2.35E-02 1.74E-02
Child Bone 3.06E+OO O.OOE+OO O.OOE+OO 1.73E-OI 1.44E-OI l.07E-OI
Nearest Ayg.Lung 1.49E+OO O.OOE+OO O.OOE+OO l.07E-OI 8.86E-02 6.55E-02
Potential Bronchi 2.37E-03 O.OOE+OO O.OOE+OO 5.96E-05 4.90E-05 3.59E-05
Resident Effective 6.36E-OI O.OOE+OO O.OOE+OO 3.71E-02 3.07E-02 2.26E-02
(BHV-I)Bone 1.1IE+OI O.OOE+OO O.OOE+OO 5.95E-OI 4.9IE-OI 3.6IE-OITeenageAvg.Lung 1.17E+OO O.OOE+OO O.OOE+OO 8.48E-02 7.0IE-02 5.16E-02
Bronchi 2.37E-03 O.OOE+OO O.OOE+OO 5.96E-05 4.90E-05 3.59E-05
Effective 3.72E-OI O.OOE+OO O.OOE+OO 2.29E-02 1.89E-02 1.40E-02
Adult Bone 4.80E+OO O.OOE+OO O.OOE+OO 2.88E-O I 2.38E-OI 1.76E-OI
Avg.Lung 7.89E-OI O.OOE+OO O.OOE+OO 5.70E-02 4.72E-02 3.48E-02
Bronchi 2.37E-03 O.OOE+OO O.OOE+OO 5.96E-05 4.90E-05 3.59E-05
Effective 1.90E-OI O.OOE+OO O.OOE+OO 8.54E-03 7.63E-03 7.59E-03
Infant Bone 6.49E-OI O.OOE+OO O.OOE+OO 3.74E-02 3.34E-02 3.33E-02
Avg.Lung 1.79E-OI O.OOE+OO O.OOE+OO 2.07E-02 1.86E-02 1.84E-02
Bronchi 3.27E-04 O.OOE+OO O.OOE+OO 1.45E-05 l.28E-05 l.28E-05-
Effective 7.82E-02 O.OOE+OO O.OOE+OO 7.27E-03 6.46E-03 6.46E-03
Child Bone 4.48E-OI O.OOE+OO O.OOE+OO 4.48E-02 3.98E-02 3.98E-02
Nearest Ave.Lung 2.2IE-OI O.OOE+OO O.OOE+OO 2.73E-02 2.42E-02 2.43E-02
Historical Bronchi 3.27E-04 O.OOE+OO O.OOE+OO 1.45E-05 l.28E-05 l.28E-05
Resident Effective 9.llE-02 O.OOE+OO O.OOE+OO 9.26E-03 8.2IE-03 8.22E-03
(BHV-2)-
Bone 1.58E+OO O.OOE+OO O.OOE+OO 1.47E-OI 1.30E-OI I.3IE-OITeenageAvg.Lung 1.7IE-OI O.OOE+OO O.OOE+OO 2.13E-02 1.89E-02 1.90E-02
Bronchi 3.27E-04 O.OOE+OO O.OOE+OO 1.45E-05 l.28E-05 l.28E-05
Effective 5.39E-02 O.OOE+OO O.OOE+OO 5.80E-03 5.15E-03 5.14E-03
Adult Bone 6.93E-OI O.OOE+OO O.OOE+OO 7.27E-02 6.45E-02 6.45E-02
Avg.Lung 1.16E-OI O.OOE+OO O.OOE+OO 1.44E-02 1.28E-02 1.28E-02
Bronchi 3.27E-04 O.OOE+OO O.OOE+OO 1.45E-05 l.28E-05 l.28E-05
34489-10 --FINAL -Apri12008 C-IO SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4B for White Mesa Uranium Mill
TABLE C.2-2 (Cont'd)
40 CFR 190 ANNUAL DOSE COMMITMENTS
(ARIZONA STRIP ORE)
_.
Estimated Dose (mrem/yr)
Location Age Organ Mill Area Interim Soil Cover Active
Gronp (including Tailings Tailings Tailings Tailings Tailings
ore pads)Cell 2 Cell 3 Cell 3 Ce1l4A Ce1l4B
Effective 7.69E-Ol O.OOE+OO O.OOE+OO 2.23E-02 L89E-02 L6IE-02
Jnfant Bone 2.60E+OO O.OOE+OO O.OOE+OO 9.79E-02 8.29E-02 7.06E-02-
Avg.Lung 6.l9E-Ol O.OOE+OO O.OOE+OO 5.J9E-02 4A3E-02 3.79E-02
Bronchi L36E-03 O.OOE+OO O.OOE+OO 4.IIE-05 3.43E-05 2.90E-05
Effective 3.08E-Ol O.OOE+OO O.OOHOO L98E-02 L67E-02 L4IE-02
Child Bone L75E+OO O.OOHOO O.OOE+OO L2JE-Ol L02E-OJ 8.66E-02
Avg.Lung 8AlE-OJ O.OOHOO O.OOE+OO 7.47E-02 6.27E-02 5.32E-02NearestBronchiL36E-03 O.OOE+OO O.OOE+OO 4.IIE-05 3.43E-05 2.90E-05Actual
Resident Effective 3.62E-Ol O.OOE+OO O.OOE+OO 2.57E-02 2.16E-02 L83E-02
Teenage Bone 6.33E+OO O.OOE+OO O.OOE+OO 4.l3E-Ol 3.44E-Ol 2.91E-Ol
Avg.Lung 6.63E-Ol O.OOE+OO O.OOE+OO 5.90E-02 4.94E-02 4.19E-02
Bronchi L36E-03 O.OOHOO O.OOE+OO 4.11E-05 3.43E-05 2.90E-05
Effective 2.l2E-Ol O.OOE+OO O.OOE+OO L60E-02 L34E-02 LI3E-02
Adult Bone 2.72E+OO O.OOE+OO O.OOHOO 2.0IE-Ol L68E-Ol L42E-Ol
Avg.Lung 4A4E-Ol O.OOE+OO O.OOE+OO 3.97E-02 3.32E-02 2.82E-02
Bronchi L36E-03 O.OOE+OO O.OOE+OO 4.IIE-05 3.43E-05 2.90E-05
Effective 7.59E-02 O.OOE+OO O.OOE+OO 4.83E-03 5.06E-03 4.36E-03.-
Infant Bone 2.59E-Ol O.OOE+OO O.OOE+OO 2.09E-02 2.l9E-02 L89E-02
Avg.Lung 8.79E-02 O.OOE+OO O.OOE+OO L37E-02 L44E-02 L24E-02
Bronchi 9.8IE-05 O.OOE+OO O.OOE+OO 4.94E-06 5.23E-06 4A8E-06
Effective 2.66E-02 O.OOE+OO O.OOE+OO 3.29E-03 3.45E-03 2.96E-03
Child Bone L56E-Ol O.OOE+OO O.OOE+OO 2.10E-02 2.2IE-02 L90E-02
Avg.Lung 7.28E-02 O.OOE+OO O.OOE+OO L23E-02 L29E-02 LIlE-02
White Mesa Bronchi 9.81 E-05 O.OOE+OO O.OOE+OO 4.94E-06 5.23E-06 4A8E-06
Community Efective 2.75E-02 O.OOE+OO O.OOE+OO 3.7IE-03 3.9IE-03 3.36E-03
Teenage Bone 4.73E-Ol O.OOE+OO O.OOE+OO 5.70E-02 6.00E-02 5.l6E-02
Avg.Lung 5.IIE-02 O.OOE+OO O.OOHOO 8.78E-03 9.24E-03 7.95E-03
Bronchi 9.8IE-05 O.OOE+OO O.OOE+OO 4.94E-06 5.23E-06 4A8E-06
Effective L70E-02 O.OOE+OO O.OOE+OO 2A7E-03 2.60E-03 2.24E-03
Adult Bone 2.l9E-Ol O.OOE+OO O.OOE+OO 3.07E-02 3.23E-02 2.79E-02
Avg.Lung 3.60E-02 O.OOE+OO O.OOE+OO 6.l5E-03 6A7E-03 5.56E-03
Bronchi 9.8IE-05 O.OOHOO O.OOE+OO 4.94E-06 5.23E-06 4A8E-06
34489-10 --FINAL -April 2008 C-ll SENES Consultants Limited
Proposed Development ofNew Tailings Cell 4Bfor White Mesa Uranium Mill
TABLE C.2-2 (Cont'd)
40 CFR 190 ANNUAL DOSE COMMITMENTS
(ARIZONA STRIP ORE)
Estimated Dose (mrem/yr)
Location Age Organ Mill Area Interim Soil Cover Active
Gronp (inclnding Tailings Tailings Tailings Tailings Tailings
o,'e pads)Cell 2 Cell 3 Cell 3 Ce1l4A Ce1l4B-_.
Effective 5.12E-02 O.OOE+OO O.OOHOO 2,68E-03 2.57E-03 2.63E-03
Infant Bone 1.73E-OI O.OOE+OO O.OOE+OO 1.17E-02 1.12E-02 1.15E-02---
Avg.Lung 4.77E-02 O.OOE+OO O.OOHOO 6.7IE-03 6.45E-03 6.58E-03
Bronchi 8.07E-05 O.OOE+OO O.OOE+OO 4.16E-06 3.99E-06 4.11E-06
Effective 1.93E-02 O.OOE+OO O.OOE+OO 2.19E-03 2.10E-03 2.15E-03
Child Bone l.lOE-OI O.OOE+OO O.OOHOO 1.35E-02 1.30E-02 1.33E-02
Avg.Lnng 5.25E-02 O.OOE+OO O.OOE+OO 8.2lE-03 7.87E-03 8.07E-03
Blanding Bronchi 8.07E-05 O.OOE+OO O.OOE+OO 4.16E-06 3.99E-06 4.IIE-06
Effective 2.17E-02 O.OOE+OO O.OOE+OO 2.73E-03 2.6IE-03 2.69E-03
Teenage Bone 3.77E-Ol O.OOE+OO O.OOE+OO 4.32E-02 4.14E-02 4.25E-02
Avg,Lung 3.97E-02 O.OOE+OO O.OOHOO 6.3IE-03 6.04E-03 6.2IE-03
Bronchi 8.07E-05 O.OOE+OO O.OOE+OO 4.16E-06 3.99E-06 4.1IE-06
Effective 1.29E-02 O.OOE+OO O.OOE+OO 1.72E-03 1.66E-03 1.70E-03
Adult Bone 1.66E-O1 O.OOHOO O.OOE+OO 2.16E-02 2.07E-02 2.13E-02
Avg.Lung 2.7IE-02 O.OOHOO O.OOE+OO 4.29E-03 4.IIE-03 4.23E-03
Bronchi 8.07E-05 O.OOE+OO O.OOE+OO 4.16E-06 3.99E-06 4.IIE-06
34489-10 ..FINAL-April 2008 C-12 SENES Consultants Limited
Appendix C
121 Granton Drive
Unit 12
Richmond Hill,Ontario
Canada L4B3N4
t::=:::J SENES Consultants Limited
,_ENE'
--------------------------Tel:[phone]
Fax:[phone]
E-mail:[e-mail]
Web Site:http://www.senes.ca
34489-10
28 April 2008
Mr.Steven D.Landau
Manager,Environmental Affairs
Denison Mines (USA)Corp.
1050 17th Street,Suite 950
Denver,CO 80265
Subject:Review ofEnvironmental Radiological Monitoring Program
for the White Mesa Uranium Mill
Dear Mr.Landau:
This letter report provides a review of the environmental radiological monitoring program at
Denison's White Mesa Uranium Mill (the "Mill")in San Juan County,Utah,in support of an
application by Denison Mines (USA)Corp.(DUSA)to develop new tailings cell 4B...
Specifically,this report addresses the question of whether or not any changes to the current
environmental radiation monitoring program at the Mill site are warranted by the addition of
tailings Cell4B
In preparing this report,we directly reference and use information in Mill's 2007 Semi-Annual
Effluent Monitoring Reports (DUSA 2007 and 2008),and other information provided to us by
DUSA.
1.0 CURRENT ENVIRONMENTAL RADIOLOGICAL MONITORING PROGRAM
Annual meteorological data collected from the Mill's meteorological station show that the
predominant wind directions during the past four years (2004-2007)were blowing from the
north-north-easterly and northerly directions (Turk 2007 and Landau 2008b).J:he 2007 annual
frequency distribution is presented graphically in Figure 1.The wind blows from the north-
north-easterly (at an average speed of 2.8 mis,14.9%of the time)and northerly (at an average
speed of 3.1 mis,14.0%of the time)(Landau 2008b).The locations of the air monitoring
stations are also shown on Figure 1.These data are considered to represent long term wind
patterns at the Mill.Air monitoring stations BHV-1 and BHV-2 will detect radiological
Specialists in Energy,Nuclear and Environmental Sciences
34489-10
28 April 2008
Letter to S.Landau (Continued)Page 2
characteristics of winds from the south and station BHV-4 and BHV-6 will detect radiological
characteristics ofwinds from the north.
The current radiological monitoring program at the Mill has the following environmental media
and conditions (DUSA 2007 and 2008):
1.Air particulate radionuclide concentrations from the following sampling stations (see
Figure 2):
•North,East,and South of the Mill site:BHV-I &BHV-2 (north),BHV-5 (east),
BHV-4 (south);
•BHV-3 (a background station west of the Mill)used to monitor airborne particulate
until November 1995 and subsequently decommissioned with the approval of the
United States Nuclear Regulatory Commission (NRC);
•BHV-6 (station specifically requested by the White Mesa Ute Community south of
the Mill site).
2.External (direct)gamma radiation measurements at air monitoring stations BHV-1,
BHV-2, BHV-3,BHV-4,aBHV-5 and BHV-6.
3.Radon-222 is measured at air monitoring stations BHV-1, BHV-2,BHV-4,BHV-5 and
BHV-6.
4.Vegetative uptake ofradionuclides at three periphery locations.
5.Stack releases from the facility's air emissions sources.
6.Annual Surface water samples from within Cottonwood Creek and,when flowing,the
Westwater Creek drainage,both located west ofthe Mill.
7.Annual Soil radionuclide activity obtained near the air monitoring station.
8.Groundwater at the Mill facility,as well as up gradient and down gradient).
2.0 REVIEW OF ENVIRONMENTAL RADIOLOGICAL MONITORING PROGRAM
In order to review the adequacy ofthe environmental radiological monitoring program in light of
the addition of Cell 4B,some general observations from the semi-annual effluent reports for
2007 (DUSA 2007 and 2008)and meteorological data are provided:
•The current BHV stations cover the predominant wind directions:BHV-1 and BHV-2
cover winds that flow predominantly from the south,and BHV-4 and BHV-6 cover the
winds predominantly flowing from the north of the Mill.
•The annual mean wind speed was 3.4 m/s;
34489-10
28 April2008
Letter to S.Landau (Continued)Page 3
•The measured activity of airborne particulate (V-nat,Th-230,Ra-226 and Pb-210)at all
monitoring stations shown in Figure 2 were well below regulatory Effluent Concentration
Limits (ECLs)and the Mill's "As Low As Reasonably Achievable"(ALARA)goals (i.e.,
25%of the ECL);
•Previously,radon monitoring had been carried out but was discontinued with the
agreement of the NRC in 1995.However,over time,radon detection has improved and
alpha track monitoring for radon was implemented at the environmental monitoring
stations in the 1st quarter of 2007.The measured radon-222 concentration values are
compared to derived ECLs which serve an ALARA goal.It is noted that the annual
average radon-222 concentrations were less than the evaluation values for 2007.
•Results of thermoluminescent (TLD)measurement for external gamma radiation indicate
gamma levels generally consistent with the local background,which although variable
due to local geology and variation in altitude,is about 120 mrem per year (30 mrem per
quarter),except for BHV-1 (which is adjacent to the front gate)and BHV-5 (near the site
boundary.
•2007 data compared to previous years indicate no increase in uptake ofRa-226 or Pb-21 0
in vegetation and are well within the range ofprevious sampling episodes.Moreover,the
droughts in recent years have affected the availability of vegetative species at the three
sampling locations.
•Stack releases were reported but these are direct stack measurements and are not
comparable to ECLs which for regulatory compliance purposes are site boundary
standards.
•Soil samples collected for fall 2007 showed that Ra-226 and V-nat concentrations were
near background.
•Surface water samples were collected at Cottonwood Creek but radionuclide data did not
indicate trending over time nor influences from the Mill operations.Westwater Creek
was not able to be sampled because it was dry for the sampling events.
The results from DVSA (2007)did not show any anomalies from the historical data,which
indicates the Mill's ALARA practices are adequately protecting the people and the environment.
The measured radon-222 concentration were less than the derived ECLs;however,it is
understood that monitoring will be continued to identify trends over time..
3.0 EVALUATION
In our opinion,the current environmental radiological monitoring program is quite
comprehensive and provides adequate measurements to provide assurance that the current
activities at the Mill are not adversely affecting the local environment and to confirm the
MILDOS modelling.
MILDOS modelling has shown that the introduction of tailings cell 4B will have no material
effect on the exposures and doses to people living nearby the Mill.In part,this is due to the
nature of local winds that predominantly blow from the north-north-easterly and northerly
34489-10
28 April 2008
Letter to S.Landau (Continued)Page 4
directions based on the meteorological data from the last four years.As a result,any dust or
radon from activities at the site will tend to disperse towards the valley to the west of the cell
away from nearby residents.Thus,existing monitoring is adequate for ensuring protection of
people who live near the Mill.
Given our understanding ofthe existing monitoring data and the low doses to people who live or
undertake recreational activities such as hiking or hunting near the Mill,in our opinion the
current environmental radiological monitoring is adequate and consistent with the objectives set
out in the NRC's Regulatory Guide 4.14,Radiological Effluent and Environmental Monitoring
at Uranium Mills (NRC 1980.
In closing,the current radiological monitoring program at the Mill adequately monitors the
release ofradioactive materials to the local environment associated with current Mill activities.
Should you have any questions or comments on this letter,please contact us at your convenience.
Yours very truly,
SENES Consultants Limited
Douglas B.Chambers,Ph.D.
Vice-President,Director of
Radioactivity and Risk Studies
34489-10
28 April 2008
Letter to S.Landau (Continued)
REFERENCES
Page 5
Denison Mines (USA)Corp.(DUSA)2007.White Mesa Uranium Mill Radioactive Materials
License UT900479 Semi-Annual EfJluent Monitoring Report (January through June,
2007).December.
Denison Mines (USA)Corp.(DUSA)2008.White Mesa Uranium Mill Radioactive Materials
License UT900479 Semi-Annual EfJluent Monitoring Report (July through Decemeber,
2007).March.
Landau,S.2008a.E-mail to D.Chambers:FW:34489 Environmental Rad Monitoring at White
Mesa Mill
Landau,S.2008b.E-mail to D.Chambers:2007 Windrose
Turk,D.2007.E-mail to D.Chambers:FW:Additional Weather Information.
United States Nuclear Regulatory Commission (NRC)1980.Regulatory Guide 4.14,
Radiological EfJluent and Environmental Monitoring at Uranium Mills-Rev.1.
34489-10
28 April 2008
Letter to S.Landau (Continued)Page 7
FIGURE 2
LOCATION OF AIR MONITORING STATIONS
N
1-_.--II
I
II
I(
-I
I(~!
,: 1I/I1-__.J
III
!
-I •
BI\fV-2
I
\
(
~\
'\
Ii
Property Boundary
Reservation Boundary_.._11_Canyon Rim
•Air Monitoring Stations
...........
!! !!!!
~.FDT
SOURCE:Adaptedfrom Denison Mines(USA)Corp.,Figure 3.3·2.dwg.,February,2007
34489-10
28April 2008
Letter to S.Landau (Continued)Page 6
FIGURE 1
2007 WIND ROSE PLOT
__IIDT:.........
IIIIIdlng,UtItI
WlNDIf'EED
(IIIIa)
0-'1.1Ii!U·1U..,·u
U·1.7
2.1·U
•"'·2.1
e:-Uft
,,
,
/
I
/
.--
I
I
I
lSO\nH....L_."..
,.,,
,1ft,,,,,,.,,
I,,
I I;,I
I
I \
f ,\\
f I \
;I
,
~wESi .i.'.,;.!,--i ..---I,,EAST,
,
'.
"
lIiITll_--
OUI_
-1IcV..........et"IU'••Figure 3
17D....__INIIO:
201...
_arv....~__
34489-10
28 April 2008
Letter to S.Landau (Continued)
FIGURE 2
LOCATION OF AIR MONITORING STATIONS
N
1 II-----II
I
Page 7
SOURCE:Adapted from Denison Mines (USA)Corp_,Figure 3_3-2_dwg_,February,2007
___Property Boundary
ReselVatlon Boundary_11_11_Canyon Rim
•Air Monitoring Stations
_0 _
! ! !!!!
ICIIU:ItIUT