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HomeMy WebLinkAboutDRC-2009-004063 - 0901a06880141abe0^C^ .^LOC'l'CO^DbZ DENISOlsr^i MINES Mr. Loren Morton Utah Department of Environmental Quality 168 North 1950 West P.O. Box 144810 Salt Lake City, UT 84114-4810 Denison Mines (USA) Corp. 1050 17th Street, Suite 950 Denver, CO 80265 USA Tel : 303 628-7798 Fax: 303 389-4125 www.denisonmines.com Re: Environmental Report In Support of Construction Tailings Cell 4B White Mesa Uranium Mill-Blanding, Utah Dear Mr. Morton: Please find enclosed two electronic copies and two hard copies of the revised Environmental Report In Support of Construction Tailings Cell 4B White Mesa Uranium Mill Blanding, Utah. The revised report includes changes necessary to address the comments of Mr. Robert Baird received by Denison on August 20, 2009. I have also enclosed a blackline/strikeout version of the main text in order for UDEQ to identify the changes in the document. Please note that there were also some modifications made to the introduction in order to provide better clarification and support for the document. If you should have any questions regarding this document, please contact me. Yours truly, Steven D. Landau DENISON MINES (USA) CORP. Manager, Environmental Affairs cc: Ron Hochstein Harold Roberts David Frydenlund David Turk Environmental Report In Support of Construction Tailings Cell 4B White Mesa Uranium Mill landing Utah Prepared by Denison Mines USA Corp 1050 17th Street Suite 950 Denver Colorado 80265 April 30 2008 Revised and Resubmitted on September 11 2009 Introduction Denison Mines USA Corp Denison is seeking an amendment to its Radioactive Materials License No UT1900479 the License in order to obtain the approval of the Executive Secretary of the State of Utah Radiation Control Board the Executive Secretary to construct operate and when operations are complete reclaim proposed new tailings impoundment Cell 4B at its White Mesa Uranium Mill the Mill The construction of Cell 4B is an essential element of future operations at the Mill as its construction is necessary in order to continue providing sufficient impoundment surface area for the evaporation of Mill process water This Cell will also provide additional tailings capacity which is necessary to accommodate the tailings volume associated with routine ore processing operations While the new cell has not yet been constructed it was contemplated described and assessed previously being critical component of the initial environmental analysis and attendant licensing of the facility See the Environmental Report White Mesa Uranium Project San Juan County Utah January 30 1978 prepared by Dames Moore the 1978 ER and the Final Environmental Statement Related to Operation of the White Mesa Uranium Project Energy Fuels Inc May 1979 the FES prepared by the United States Nuclear Regulatory Commission NRC These initial environmental analyses and the License contemplated six tailing cells that would contain approximately 11 million tons of tailings solids which would be the tailings resulting from 15 years of Mill operations at full capacity see Section 3.2.4.7 of the FES and Section 3.4 and Appendices and of the 1978 ER These are evaporation pond Cell 1-I now referred to as Cell second evaporation pond Cell 1-E which has not been constructed and series of 80-acre cells of which Cells and and half of Cell Cell 4A have been constructed to date Cell 4A is currently in the process of being re-lined 80-acre Cells and have been specifically contemplated and included in the License see Figure 3.4 of the FES With the construction of Cell 4A 40 acres Cell 4B will consume the second 40 acres of the previously authorized 80 acre Cell The information required for an amendment to the License is found at R3 13-24-3 More specifically the regulations state the following Each new license application renewal or maj or amendment shall contain an environmental report describing the proposed action statement of its purposes and the environment affected The environmental report shall present discussion of the following 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 An assessment of any impact on waterways and groundwater resulting from the activities conducted pursuant to the license or amendment Consideration of alternatives including alternative sites and engineering methods to the activities to be conducted pursuant to the license or amendment and 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 Standard Review Plan for In Situ Leach Uranium Extraction License Applications Final Report June 2003 NUREG 1569 for its recent White Mesa Uranium Mill License Renewal Application State of Utah Radioactive Materials License No UT1900479 February 28 2007 the License Renewal Application and supporting Environmental Report dated February 28 2007 the 2007 ER This Report is not in support of an application for the License or renewal of the License as whole which are addressed in the License Renewal Application and the 2007 ER nor is it an application for approval of the siting and use of Cell 4B which have already been evaluated and approved and are included in the License as part of the approval of the tailings management system for the Mill Rather this Report is in support of the more detailed amendments to the License required in connection with the actual construction and operation of Cell 4B Because the License 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 and operation of the new tailings cell Accordingly topical headings suggested by NUREG 1569 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 Specifically the following environmental evaluations that have been performed for the Mill are incorporated by reference into updated or supplemented by this Report The 1978ER TheFES The Environmental Assessment EA prepared by the NRC in September 1985 for the Mill License renewal at that time the 1985 EA see NRC 1985 The EA prepared by NRC in February 1997 for the Mill License renewal at that time the 1997 EA see NRC 1997 The EA prepared by NRC in February 2000 for the Mills Reclamation Plan the 2000 EA see NRC 2000 and The EA prepared by NRC in August 2002 in connection with License amendment issued by NRC authorizing receipt and processing at the Mill of certain alternate feed materials from the Maywood site in New Jersey the 2002 EA see NRC 2002 Denisons assessment of the pathways to be considered for construction and operation 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 tailing cell These are the only two significant pathways that could be impacted by Cell 4B installation and operation In addition an archaeological study is being performed on the surface area that will be impacted by construction of Cell 4B as required by License condition 9.7 which will be provided to the Executive Secretary in separate report It is important to note that the Executive Secretary 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 of Cell 4A This Environmental Report is dated as of April 30 2008 References Section was added certain terms within the body of the text were defined and number of minor edits and other clarifications were made on September 11 2009 in response to comments received by the State of Utah Department of Environmental Quality UDEQ Division of Radiation ControlDRCstaff III Table of Contents Page Introduction Table of Contents iv Index of Figures 1.0 Site Location and Layout 2.0 Climate and Meteorology 2.1 Regional Climate 2.2 Onsite Monitoring Program 3.0 Use of Adjacent Lands and Water 4.0 Population Distribution and Socioeconomic Profile 5.0 Topography 6.0 Geologic Setting 6.1 Regional Geology 6.2 Local Geology 6.3 Site-Specific Geologic Setting 7.0 Hydrologic Setting 7.1 Perched Zone Hydrogeology 7.2 Perched Groundwater Flow 7.3 Perched Hydrogeology Down-gradient of Tailings Cells 7.4 Groundwater Quality 8.0 Ecological Resources and Biota 13 8.1 Terrestrial 13 8.2 Aquatic and Wetland Biota 16 9.0 Background Radiological and Non-Radiological Characteristics 16 10.0 Environmental Effects Related Directly to the Construction of Cell 4B 16 10.1 Groundwater Pathway Impact 17 10.2 Proposed Additional Groundwater Monitoring 17 10.3 Radiological Impact 18 10.4 Proposed Radiological Monitoring to Accommodate Cell 4B Operations 20 10.5 Reclamation of Cell 4B 20 11.0 Alternatives 20 11.1 Issuance of Amendment for Cell 4B 21 11.2 No Action Alternative 21 11.3 Alternatives Considered But Eliminated 22 11.4 Cumulative Effects 23 11.5 Comparison of Predicted Environmental Impacts 23 11.6 Updates and Changes to Factors That May Cause Reconsideration 23 12.0 Costs and Benefits 23 13.0 Mitigation of Impacts 24 14.0 Long Term Impacts 24 15.0 References 26 iv Appendix 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 Hydro Geo Chem Inc January 2008 Appendix Proposed Development of New Tailings Cell 4B For the White Mesa Uranium Mill SENES Consultants Limited April 2008 Appendix Review of Environmental Monitoring Program for the White Mesa Uranium Mill SENES Consultants Limited April 28 2008 Index of Figures Figure Follows Page Figure Location Map Mill Figure Mill Land Map Figure White Mesa Wind Rose Figure Population in the Project Vicinity Figure Local Topography Figure Generalized Stratigraphy of White Mesa Mill Figure Approximate Elevation Top of Brushy Basin Figure Kriged 4th Quarter 2007 Water Levels Figure Approximate Location of Ruin Spring Figure 10 Depth to Perched Water Figure 11 Stock Watering Pond Locations 16 Figure 12 Groundwater Well or Spring Sampling Stations In the White Mesa Vicinity 16 Figure 13 Reclamation Cover Grading Plan for Cell 4B Provided As Separate Electronic Document 1.0 Site Location and Layout The Mill is regionally located in central San Juan County Utah approximately miles 9.5 km south of the city of landing The Mill can be reached by taking private road for approximately 0.5 miles west of Utah State Highway 191 See Figure Within San Juan County the Mill is located on fee land and mill site claims covering approximately 5415 acres encompassing all or part of Sections 21 22 27 28 29 32 and 33 of T37S R22E and Sections and 16 of T38S R22E Salt Lake Base and Meridian See Figure 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 The resident currently nearest to the milling facility is located approximately 1.2 miles 1.9 1cm north of the Mill site just north of the Mill property See Figure 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 of the Mill can be considered as semi-arid with normal annual precipitation of about 13.4 inches Most precipitation is in the form of rain 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 autunm 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 pan evaporation rate is 68 inches 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 pan coefficient to determine the later evaporation rate Values of pan coefficients range from 60%to 81%Denison assumes for water balance calculations an average value of 70%to obtain an annual lake evaporation rate for the Mill area of 47.6 inches Given the annual average precipitation rate of 13.4 inches the net evaporation rate is 34.2 inches per year The weather in the Blanding area is typified by warm summers and cold winters The mean annual temperature in Blanding is about 50 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 of the 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 Lb Ii Figure White Mesa Mill Location Map Property Boundary Reservation Boundary Canyon Rim Figure White Mesa Mill Land Map 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 of the 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 FES 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 of the Mill After the Mill construction was completed the monitoring programs were modified to facilitate the assessment of Mill 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 semi-annual basis and are described in semi-annual reports prepared for Denison and maintained at the Mill Figure shows the windrose for the Mill site during the period of January December 2007 the most recent full year of compiled meteorological data 3.0 Use of Adjacent Lands and Water Approximately 65.8%of San Juan County is federally owned land administered by the U.S Bureau of Land Management BLM 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 miles of the Mill site is predominantly range land owned by Blanding residents The Mill site including tailings cells encompasses approximately 300 acres 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 of archeological 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 five year frequency for population centers which exceed 65000 people and on 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 al flOT Mka littaSU wmns IflcUoei ftL.L fros 5% I2% 0% IPEED fin u-ILl UI ttts El ti-n 152.1 trw 016% tlMl DlTh 2W .S1-Dn31 St.nil an SeaMer Sn.U$a4 Cr aa Figure tar ns St sara Vats 201S-O6 WWtOT V.t..J 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 of Blanding Utah approximately miles north of the Mill is the largest population center near the Mill site with 3162 persons Approximately miles southeast of the Mill site is the White Mesa community where approximately 277 Ute Mountain Ute tribal members reside See Figure The Navajo Reservation is located approximately 19 miles southeast of the Mill The nearest community on the Navajo Reservation is Montezuma Creek community of approximately 507 individuals in Utah The nearest resident to the Mill is located approximately 1.5 miles to the north of the Mill near air monitoring station BHV -1 Table provides population centers located within 50 miles of the Mill site Table 1-Population Centers Within 50 Miles of the Mill Site Population Center 2000 Population Distan Front Site2 miles Blanding UT 3162 White Mesa UT 277 Bluff UT 320 15 Montezuma Creek UT 507 20 AnethUT 598 27 Mexican Flat UT 88 30 Monticello UT 1958 27 Eastland/Ucolo UT 249 32 Dove Creek CO 698 37 Towaoc CO 1097 50 Source http //factfinder.census Gov 2000 census Approproximate distance from Mill site by air 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 whole and 4.5%for the nation as 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 such the Mills employees represent 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 high percentage of minority workers ranging from 45-75% Native Americans Since its inception in 1980 the Mill has run on campaign basis in each case remaining on standby pending accumulation of sufficient ore stockpiles to justify milling campaign Currently Mill employees are predominantly residents of San Juan County or residents of neighboring counties who commute to the Mill on daily basis Historically the Mill has drawn Denison Mines USA Corp Figure Population in The Project Vicinity 2000 Census SCALE MILES PROPERTY BOUNDARY RESERVATION BOUNDARY CANYON RIM 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 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 gently sloping mesa that from the air appears similar to peninsula as it is surrounded by steep canyons and washes and is connected to the Abajo Mountains to the north by narrow neck of land On the mesa the topography is relatively flat sloping at less than one percent to the south and nearly horizontal from east to west See Figure 6.0 Geologic Setting 6.1 Regional Geology The Mill site lies within region designated as the Canyon Lands section of the Colorado Plateau physiographic province Elevations in the region range from approximately 3000 feet in the bottom of canyons to over 11000 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 5000 feet The sedimentary rocks exposed in southeastern Utah have total thickness of approximately 6000 to 7000 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 of origin or mechanism of the stress that created the structure These categories are structures related to large-scale regional uplifting or downwarping directly related to movements in the basement complex the Monument Uplift and the Blanding Basin structures due to diapiric defonnation of thick sequences of evaporate deposits salt plugs and salt anticlines the Paradox Fold and Fault Belt and structures formed due to magmatic intrusions the Abajo Mountains generalized stratigraphic column for the region is provided as Figure The Summerville Formation 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 northlsouth-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 4000 ft above the surface of the plain The lithology of the immediate area is composed of thousands of feet of ZA W W t e IIT k 2 0 0 7 lJ c e s t fl e e w fto p V a t h n W a v l n m t $ Re o f t- Rgs a \ M o u n 3. 7 4 S i flg w e 37 - 4 O V 2 4 t 2 I J O 32 4 1 1 rn ptc Ii 17 Fr o m US G S 7. 5 mi n u t e qu a d sh e e t fo r Bl a c k Me s a Fi g u r e Lo c a l To p o g r a p h y 10 0 0 2 0 0 0 30 0 0 SC A L E IN FE E T An d Lo c a t i o n of Ru i n Sp r i n g tn It In COVERED BY UNCONSOLIDATED ALLUVIUM COLLUV1UM AND TALUS SANDSTONE QUARTZ UGHT YELLOW BROWN POORLY SORTED IRON CONCREATIONS WELL INDURATED SANDSTONE QUARTZ LIGHT CRAY TO liGHT BROWN CROSSBEDDED CONCLOMERATIC POORLY SORTED INTERBEDDEO WITH CRAYGREEN SHALE SHALE GRAY GRAYGREEN AND PURPLE SILTY IN PART WITH SOME SANDSTONE LENSES SNIDSIONE ARKOSIC YELLOW TO GREENISH GRAY FiNE TO COARSE CRAJNED IN1ERBEDDED WITh GREENISHCRAY TO REDDISHBROWN SHALE SHALE REDDISHCRAY SILTY TO SANDY INTERBEDDED WITH SANDSTONE ARKOSIC REDDISHGRAY TO YELLOWBROWN FINE TO MEDIUMGRAINEO SANDSTONE QUARTZ YELLOWISHTO REDDISH BROWN FINETO COARSE GRAINED INTERBEDDED WITH REDDISH CRAY SHAll SANDSTONE REDBROWN THINBEDDED WITH RIPPLE MARKS ARGILLACEOUS WITh SHALE INTERBEDS SANDSTONE QUARTZ WHITE TO GRAYISH BROWN MASSIQE CROSSBEDDED FINE TO MEDIUMGRNNED SANDSTONE QUARTZ LIGHT YELLOWISH DROWN TO LIGHTGRAY AND WHITE MASSIVE CROSSBEDDED FRtABLE FINE TO MECIUMGRAINED ItNI AND AND SILT REDDISH BROWN VERY EOLIAN SAND F1NECRAINED 4RCS_$EALE HALE LIGHT GRAY Son DAKOTA SANDSTONE .\BURRO CANYON FORMATION BRUSHY BASIN MEMBER In LU LU WESTWATER CANYON MEMBER RECAPTURE MEMBER SALT WASH MEMBER SUMMERVILLE FORMATION ENTRADA SANDSTONE NAVAJO SANDSTONE Denison Mines USA Corp Figure Generalized Stratigraphy of White Mesa Mill Token from StrotiQraphic Section near Water Well 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 of the mesa is nearly flat with 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 This Section 6.3 and Sections 7.1 7.2 and 7.3 are excerpted from the Report entitled 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 January 2008 prepared by Hydro Geo Chem Inc HGC copy of which is attached to this Report as Appendix 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 underformed The average elevation of the site is approximately 5600 ft 1707 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 The alluvial materials consist mostly of aeolian silts and fine-grained aeolian sands with thickness varying from few feet to as much as 25 to 30 ft 7.6 to 9.1 across the site The alluvium is underlain by the Dakota Sandstone and Burro Canyon Formation which are sandstones having total thickness ranging from approximately 100 to 140 ft 31 to 43 Beneath the Burro Canyon Formation lies the Morrison Formation 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 Formation classified as shales are very fine-grained and have very low permeability The Westwater Canyon and Salt Wash Members also have low average vertical permeability due to the presence of interbedded shales See Figure for generalized stratigraphic column for the region Beneath the Morrison Formation lies 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 1000 to 1100 ft 305 to 335 of materials having low average vertical permeability Groundwater within this system is under artesian pressure in the vicinity of the site and is used only as secondary source of water at the site 7.0 Hydrogeologie Setting The site is located within region that has dry to arid continental climate with average annual precipitation of approximately 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 of the aquifer approximately 1200 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 of the overlying Summerville Formation 7.1 Perched Zone Hydro geology Perched groundwater beneath the site occurs primarily within the Burro Canyon Formation Perched groundwater at the site has generally low quality due to high total dissolved solids TDS in the range of 1200 to 5000 milligrams per liter mg/L and is used primarily for stock watering and irrigation in the areas upgradient north of the 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 is 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 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 of the various monitoring wells are indicated on Figure located immediately downgradient of the tailings cells at the site porosities of the 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 of the Dakota Sandstone based on packer tests in borings installed at the site ranges from 2.7 1E-06 centimeters per second cmls to 9.12E-04 cmls with geometric average of 3.89E-05 cm/s 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 -- - I - - - -t -N PR O P E R T Y BO U N D A R Y Fl 71 _ _ _ fl ti i_ _ . . . / i% II 7- _ . _ _ it II EX P L A N A T I O N MW - i l 54 7 9L MW - I l 54 7 0 55 2 2 05 5 2 0 54 8 0 54 7 0 54 6 Q -- - 55 3 0 55 4 0 /2 . L _ _ _ 55 5 0 II P4 55 5 0 55 4 O 55 3 6 o5 6 1 7 55 2 2 55 2 1 56 1 5 55 0 0 54 9 0 54 7 7 55 1 0 2/ JL J L __ S4 i o _ _ It IL 30 42 o PE R C H E D MO N I T O R I N G W E L L SH O W I N G AP P R O X I M A T E EL E V A T I O N OF B R U S H Y BA S I N CO N T A C T IN FE E T AM S L Oo Mw - f l 53 9 6 4. . r -I ti ---N C- I- -d TE M P O R A R Y P E R C H E D MO N I T O R I N G W E L L SH O W I N G AP P R O X I M A T E EL E V A T I O N OP B R U S H Y BA S I N CO N T A C T IN FE E T AM S L PI E Z O M E T E R SH O W I N G AP P R O X I M A T E EL E V A T I O N OF B R U S H Y BA S I N CO N T A C T IN FE E T AM S L WI L D l i F E PO N D CO N T O U R LI N E IN FE E T AM S L DA S H E D WH E R E UN C E R T A I N SC A L E IN FE E T Fi g u r e Wh i t e Me s a Mi l l Ap p r o x i m a t e El e v a t i o n To p of Br u s h y Ba s i n 88 2 0 28 88 7 0 55 4 0 55 3 0 55 2 0 MW - 2 54 9 2 54 9 5 32 fa 1 5 55 3 6 p- s 55 5 2 30 0 0 18.3%and water saturations of unsaturated materials range from 0.6%to 77.2%averaging 23.4%Titan July 1994 reported that the hydraulic conductivity of the Burro Canyon Formation ranges from 1.9E-07 to 1.6E-03 cmls with geometric mean of 1.1 E-05 cmls based on the results of 12 pump/recovery tests performed in monitoring wells and 30 packer tests performed in borings prior to that time Hydraulic testing of wells MW-i MW-3 MW-5 MW-i7 MW-18 MW-i9 MW-20 and MW- 22 during the week of July 2002 and newly installed wells MW-23 MW-25 MW-27 MW 28 MW-29 MW-30 MW-3i MW-32 TW4-20 TW4-2i and TW4-22 during June 2005 yielded average perched zone permeabilities ranging from approximately 2.OE-07 cm/s to 5.OE- 04 cmls similar to the range reported by previous investigators at the site 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-i7 MW-20 MW-22 and MW-25 ranged from approximately 4.OE-07 to 1.OE-04 cm/s Permeability estimates were based on pump/recovery and slug tests analyzed using several different methodologies 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 relatively continuous zone of higher permeability International Uranium USA Corporation 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-il located on the southeastern margin of the downgradient edge of tailings Cell and at MW-l4 located on the downgradient edge of tailings Cell of l.4E-03 cm/s and 7.5E-04 cm/s respectively UMETCO 1993 may indicate that this zone extends beneath the southeastern margin of the cells This zone of higher 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 nor is it evident in wells MW- MW-5 MW-12 MW-iS MW-i6 MW-i7 MW-20 MW-2i or MW-22 located south to southwest downgradient of the tailings cells based on the lithologic logs or hydraulic testing of the 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 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 limited basis as water supply to the north upgradient of the site 7.2 Perched Groundwater Flow Perched groundwater flow at the site is generally to the southlsouthwest Figure displays the local perched groundwater elevation contours at the Mill As indicated the perched groundwater EX P L A N A T I O N pe r c h e d mo n i t o r i n g we l l sh o w i n g ele v a t h n in fe e t am s l te m p o r a r y pe r c h e d mo n i t o r i n g we l l sh o w i n g ele v a t i o n in fe e t am s l pe r c h e d pie z o n i e t e r sh o w i n g ele v a t i o n in fe e t er n s t pe r c h e d mo n i t o r i n g we l l i n s t a l l e d Ap r i l 20 0 5 sh o w i n g ele v a t i o n in fe e t am s l te m p o r a r y pe r c h e d mo n i t o r i n g we l l i n s t a l l e d Ap r i l 20 0 5 sh o w i n g ele v a f o n in fe e t am s l te m p o r a r y pe r c h e d mo n i t o r i n g we l l in s t a e d 20 0 7 s h o w i n g ap p r o x i m a t e ele v a f o n c6 PIE Z . 3 56 O 1 NO T E S Lo c a t i o n s an d el e v a t i o n s fo r TW 4 - 2 3 T W 4 - 2 4 an d T W 4 - 2 5 ar e ap p r o x i m a t e Fi g u r e gradient changes from generally southwesterly in the western portion of the site to generally southerly in the eastern portion of the 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 10000 ft south-southwest of the Mill site as shown in Figure 7.3 Perched Zone Hydrogeology Beneath and Down-gradient Of the Tailings Cells As of the 3rd Quarter 2007 perched water has been encountered at depths of approximately 57 to 115 ft below land surface bls in the vicinity of the tailings cells at the site Figure 10 Beneath tailings Cell depths to water ranged from approximately 77 ft below top of casing btoc east of the cell at MW-25 to approximately 114 ft btoc at the southwest margin of the cell at MW-23 Assuming an average depth of the base of tailings Cell of 25 ft below grade this corresponds to perched water depths of approximately 52 to 89 ft below the base of the cell or an average depth of approximately 70 feet beneath the base of the cell similar assumption can be made for proposed Cell 4B The saturated thickness of the perched zone as of the 3rd Quarter 2007 ranged from approximately 93 ft in the northeast portion of the site to less than ft in the southwest portion of the site Beneath tailings Cell the saturated thickness varies from approximately 49 ft in the easternmost corner of the cell to approximately ft in the western portion of the cell South- southwest of the tailings cells the saturated thickness ranges from less than ft at MW-2 to approximately 26 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-iS MW-17 and MW- 20 is approximately 14 ft The average saturated thickness based on measurements at MW-5 MW-iS MW-3 and MW-20 which lay close to line between the center of tailings Cell 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 Perched zone hydraulic gradients currently range from maximum of approximately 0.05 feet per foot ft/ft east of tailings Cell to approximately 0.01 ft/ft downgradient of Cell between Cell and MW-20 The average hydraulic gradient between the downgradient edge of tailings Cell and Ruin Spring was approximated by HGC to be approximately 0.012 ft/ft HGC also estimated hypothetical worst case average perched zone hydraulic gradient assuming the perched water elevation to be coincident with the base of tailings Cell to be approximately 0.019 ft/ft See Section 3.2 of Appendix HGC also estimated the average permeability of the perched zone downgradient of tailings Cell based on pump/recovery test and slug test data obtained from perched zone wells located Z\V b M PS P2 O O 1 LJ w s e Re w . S fl\ E I w t f $ Rep o c t P9 g i f l 3.7 - t S s T h Rgo c 37 - 6 02/2 4 . Q 0 0 7 33 4 t l fl t te PD c li x f7 ii i Fr o m US G S 7. 5 mi n u t e qu a d sh e e t fo r Bl a c k Me s a -- \- De n i s o n Mi n e s US A Co r p Fi g u r e Wh i t e Me s a Mi l l Ap p r o x i m a t e Lo c a t i o n 10 0 0 2 0 0 0 3 0 0 0 SC A L E IN FE E T PR O P E R T Y B O U N D A R Y Ru i n Sp r i n g PR O P E R T Y BO U N D A R Y EX P L A N A T I O N pe r c h e d mo n i t o r i n g we l l sh o w i n g de p t h in fe e t te m p o r a r y pe r c h e d mo n i t o r i n g we l l sh o w i n g de p t h in fe e t pe r c h e d pie z o m e t e r sh D w i n g de p t h in fe e t pe r c h e d mo n i t o r i n g we l l i n s t a l l e d Ap r i l 20 0 5 sh o w i n g de p t h in fe e t te m p o r a r y pe r c h e d mo n i t o r i n g we l l i n s t a l l e d Ap r i l 20 0 5 sh o w i n g d e p t h in fe e t te m p o r a r y pe r c h e d mo n i t o r i n g we l l i n s t a l l e d Ma y 20 0 7 sh o w i n g de p t h in fe e t 06 6 05 5 75 l j o 4 71 06 5 06 6 09 2 if Ii 7- a - PIE Z - 5 04 7 T3 7 S T3 8 S MW - 2 0 57 9 SC A L E IN FE E T 77 30 0 0 MW - 2 2 se a MW - 2 0 79 07 1 PIE Z - 1 65 MW - 3 1 -7 9 4- s i 36 9 7I // // // // // // NO T E S Lo c a t i o n s of TW 4 - 2 3 T W 4 - 2 4 an d TW 4 - 2 5 ar e ap p r o x i m a t e Me a s u r e m e n t fo r MW - 2 6 TW 4 - 1 5 is fr o m t h e se c o n d qu a r t e r 20 0 7 // // // HY D R O GE O CH E M IN C DE P T H S T O WA T E R 3r d QU A R T E R 20 0 7 WH I T E ME S A SI T E AP P R O V E D DA T E RE F E R E N C E FIG U R E SJ S 09 / 1 0 / 2 0 0 9 H/ 7 1 8 0 0 0 / I w n j u I O 9 / d t w O 8 O 7 f i g I O . s r f 10 along the downgradient edge of and south of Cell to be between 2.3E-05 cmls and 4.3E-05 cmls See Section 3.3 of Appendix 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 single aquifer Water in the Entrada/Navajo Aquifer is under artesian pressure rising 800 to 900 ft above the top of the Entradas contact with the overlying Summervillle Formation static water levels are 390 to 500 ft below ground surface Within the region this aquifer is capable of yielding domestic quality water at rates of 150 to 225 gpm and for that reason it serves as secondary source of water 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 of the Navajo/Entrada aquifer are generally good the depth of the aquifer 1000 ft bls makes access difficult Table is tabulation of groundwater quality of the Navajo Sandstone aquifer as reported in the FES and subsequent sampling The TDS range from 244 to 1110 mg/liter in three samples taken over period from January 27 1977 to May 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 1000 to 1100 ft of materials having low average vertical permeability sampling of the Navajo Sandstone is not required under the Mills previous NRC Point of Compliance monitoring program or under the Mills State of Utah Groundwater Discharge Permit No.UGW370004 the GWDP However samples were taken at two other deep aquifer wells and on site See Figure 12 for the locations of these wells on June 1999 and June 1999 respectively and the results are included in Table Table Water Quality of Groundwater in the Mill Vicinity Parameter FES Test Well G2R 1/27/77 3/23/781 Well 6/01/991 Well 6/08/991 Field Specific Conductivity umhos/cm 310 to 400 Field pH 6.9 to 7.6 Temperature 11 to 22 Estimated Flow gpm 10920 pH 7.9 to 8.16 Parameter FES Test Well G2R 1/27/77 3/23/781 Well 6/01/991 Well 6/08/991 Determination mg/liter TDS@180C 216to1110 Redox Potential 211 to 220 Alkalinity as CaCOS3 180 to 224 Hardness total as CaCO3 177 to 208 Bicarbonate 226 214 Carbonate as CU3 0.0 1.0 1.0 Aluminum 0.003 0.058 Aluminum dissolved 0.1 Ammonia as 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 cO.lto 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 5U4 17 to 83 Vanadium 0.003 0.003 Vanadium dissolved .002 to 0.16 Maganese 0.011 0.032 Maganese 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 10 Parameter FES Test Well G2R 1/27/77 3/23/781 Well 6/01/991 Well 6/08/991 Iron total 0.35 to 2.1 0.43 0.20 Iron dissolved 0.30 to 2.3 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 0.00 0.00 Molybdenum 0.001 0.001 Molybdenum dissolved 0.004 to 0.0 10 Nickel 0.00 0.004 Nitrate Nitrate as 0.10 0.10 Nitrate as .05 to 0.12 Phosphorus total as 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 Si02 5.8 to 12 Strontium total as 0.5 to 0.67 Thallium 0.00 0.00 Uranium total as .002 to 0.16 0.0007 0.0042 Uranium dissolved as .002 to 0.03 Zinc 0.010 0.126 Zinc dissolved 0.007 to 0.39 Total Organic Carbon 1.1 to 16 Chemical Oxygen Demand ito 66 Oil and Grease Total Suspended Solids 6to 1940 1.0 10.4 Turbidity 5.56 19.1 Determination pCi/liter Gross Alpha 1.0 11 Parameter FES Test Well G2R 1/27/77 3/23/78 Well 6/01/99 Well 6/08/991 Gross Alpha precision 1.61.3 to 10.22.6 Gross Beta 2.0 Gross Beta precision 88 to 7319 Radium 226 precision 0.30.2 Radium 228 1.0 Ra 226 precision 0.1.3 to 0.60.4 Th 230 precision 10.4 to 0.72.7 Pb 210 precision 0.04.0 to 1.02.0 Po 210 precision 0.00.3 to 0.00.8 Zero values 0.0 are below detection limits 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 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 TDS measured in water sampled from upgradient and downgradient wells range between approximately 1200 and 5000 mg/l Sulfate concentrations measured in three upgradient wells varied between 670 and 1740 mg/l Titan July 1994 The perched groundwater therefore is used primarily for stock watering and irrigation The saturated thickness of the perched water zone generally increases to the north of the site See Section 3.1 of Appendix At the time of renewal of the Mill license by the NRC in March 1997 and up until issuance of the Mills GWDP in March 2005 the Mill implemented groundwater detection monitoring program to ensure compliance to 10 CFR Part 40 Appendix in accordance with the provisions of 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 1994 Titan September 1994 Under that program the Mill sampled monitoring wells MW-5 MW-ll MW-12 MW-14 MW-iS and MW-17 on quarterly basis Samples were analyzed for chloride potassium nickel and uranium and the results of such sampling were included in the Mills Semi-Annual Effluent Monitoring Reports that were filed with the NRC up until August 2004 and with the DRC subsequent thereto 12 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 of Compliance 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 Flora The natural vegetation presently occurring within 25-mile 40-km 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 codominant or sub dominant 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 Comirion 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 Of the 65 proposed endangered species in Utah at that time six have documented distributions in San Juan County 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 threatened species since the Dames Moore study In completing its the 2002 EA see NRC 2002 NRC staff contacted 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 of moisture 2002 EA at 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 species was based on direct observations trappings and signs such as the occurrence of scat tracks or burrows total of 13 174 vertebrate species potentially occur within the vicinity of the Mill 1978 ER Appendix 78 of which 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 of birds were observed in the vicinity of the 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 of these species were located at the time of the FES all except the golden eagle Aquila chrysaetos have suitable nesting habitat in the vicinity of the site The nest of 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 of use per acre in the pinyon-juniper-sagebrush habitats in the vicinity of the project site In addition this area is heavily used as 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 of the local deer herd is not known 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 of rodents 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 1977 black-tailed ackrabbits Lepus californicus 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 of the endangered threatened and candidate species that may occur in the area around the site 14 Table 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 lack-footed Ferret Mustela nigripes Endangered Source 2002 EA The 2002 EA also noted that in addition the species listed on Table may occur within the Mill area that are managed under Conservation Agreements/Strategies Table 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 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 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 15 8.2 Aquatic and Wetlands iota 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 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 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 water source for small mammals and birds Similar ephemeral catch and seepage basins are typical and numerous to the northeast of the 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 water source for wildlife and temporary habitat for insect and amphibian species In the 2002 EA NRC staff concluded that no populations of fish are present on the project site nor are any known to exist in the immediate area of the 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 of the Mill 9.0 Background Radiological and Non-Radiological Characteristics Background Radiological and Non-Radiological Effects have been evaluated updated and reported extensively in Denisons February 28 2007 License License Renewal Application and accompanying 2007 ER incorporated here by reference 10.0 Environmental Effects Related Directly to the Construction of Cell 4B 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 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 4B White Mesa Uranium Mill Site Near Blanding Utah Hydro Geo Chem Inc January 2008 and 16 ZzW T h I t e MII\ 2 0 0 7 Lk a r e e RE i e w d pII r a t h n \ E r r t o a w e Rei c r t flg w V 1 n 3.7 - 7 4 9 Agu e 3.7 - 7 DV 2 4 / 2 7 31 9 1 3 Ado b e PV f . p c 3 li x 17 TE M P O R A R Y PE R C H E D M O N I T O R I N G W E L L SH O W I N G D E P T H T O WA T E R IN FE E T ST O C PI E Z O M E T E R SH O W I N G D E P T H T O WA T E R IN FE E T BT O C WI L D L I F E PO N D NO T E DA T A F O R P I E Z O M E T E R S AR E FR O M A U G U S T 20 0 2 Fi g u r e 11 Wh i t e Me s a Mi l l PE R C H E D M O N I T O R I N G WE L L SH O W I N G DE P T H TO WA T E R IN FE E T BT O C St o c k Wa t e r i n g Po n d Lo c a t i o n s __ _ tt aI /4 -p ii 20 0 0 Si 1_ -v 20 0 0 -j SC A L E IN FE E T Gi n II __ _ _ ii MIL L SIT E 02 R tL L NO ij en AG 4 R EL L N 0 . 2 NO CE L L No 4A si 54 itSi c -0 cJ Hz SW 2t 1- Sp r i n g Ru i n st R 19 1 it Sr St ti l t LI v. a -Ø II St 5% 4t -% f r TE M It 5- 04 R GR O U N D W A T E R WE L L OR SP R I N G SA M P L I N G L O C A T I O N LI ci hj J T -A it t __ WA T E R SU P P L Y W E L L 00 PR O P E R l Y BO U N D A R Y ii i i RE S E R V A T I O N BO U N D A R Y De n i s o n Mi n e s US A Co r n CA N Y O N RI M WH I T E ME S A MI L L Fi g u r e 12 Gr o u n d w a t e r We l l or Sp r i n g St a t i o n s in th e Wh i t e Me s a Vi c i n i t y Sa m p l i n g as s h o w n Da t e Au n 20 0 9 fiq u r e 2.d Dra f t e d 0y Proposed Development of New Tailings Cell 413 For the White Mesa Uranium Mill SENES Consultants Ltd April 2008 These evaluations are provided as Appendix and Appendix respectively and are discussed in summary in the pertinent subsections below 10.1 Groundwater Pathway Impact The evaluation provided by HGC finds that travel time for any water exiting the pond to the perched water zone and then to the points 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 Cell or Cell 4B 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 systems are robust and in the case of Cell 4B state-of-the art construction travel time through the liner is significant protective factor In fact this aspect has been evaluated extensively by MWH Americas Inc in their report Infiltration and Contaminant Transport Modeling Report 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 GWDP at Part I.D.6 More specifically MWH concluded that the approved reclamation plan for the cells will meet the following regulatory requirements for period of not less than 200 years Minimize infiltration of precipitation or other surface water into the tailings including but not limited to the radon barrier Prevent the accumulation of leachate head within the tailings waste layer that could rise above or over-top the maximum flexible membrane liner elevation internal to any disposal cell i.e create bathtub effect and Ensure that groundwater quality at the compliance monitoring wells does not exceed Ground Water Quality Standards or Ground Water Compliance Limits specified in Part .C.l and Table of the GWDP 10.2 Proposed Additional Groundwater Monitoring In order to monitor the performance of Cell 4B and consistent with United States Environmental Protection Agency EPA Guidance it was concluded by HGC that an additional well or wells will be needed to monitor the Cells performance at the downgradient edge of the Cell This is in addition to the many wells already incorporated into the GWDP for the facility Accordingly two additional wells are proposed one at the southwest corner of proposed Cell 4B and one between such southwest corner well and existing well MW-15 See Figure 10 of Appendix These installations will conservatively maintain the approximate existing spacing as defined by the proximity of MW-14 to MW-iS along the downgradient edge of existing Cell 4A 17 10.3 Radiological Impact In February 2007 dose assessment was prepared for Denison by SENES Consultants Ltd in support of the License Renewal Application see Appendix to the 2007 ER MILDOS-AREA was used to estimate the dose commitments that could potentially be received by individuals and the general population within 50 mile 80 km radius for processing of conventional ores The assessment was prepared for scenarios in which Colorado Plateau 0.25%U308 and 1.5% V205 or Arizona Strip 0.637%U308 ores are processed at the Mill In order to evaluate the radiological impact of Cell 4B 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 Appendix to this Report Proposed Development of New Tailings Cell 4B 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 NRC-approved MILDOS-AREA was used to estimate the dose commitments received by individuals and the general population within 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 For purposes of modeling Mill operations SENES separated operations into two phases to reflect the sequencing of planned Mill operations Phase involves the continued use of Cell for solution evaporation the continued use of Cell for solution evaporation and the disposal of tailings solids and the use of Cell 4A for disposal of tailings solids and solution evaporation Phase occurs after Cell is full and is no longer an active cell During Phase Cells 4A and 4B are used for disposal of tailings solids and solution evaporation and Cell is used for solution evaporation In each Phase Cell with interim soil cover over the entire cell area is included in the model and in Phase Cell with interim soil cover over the entire cell area is included in the model Table provides summary of the source terms included in Phases and of the development of new tailings cells including Cells 4A and 4B TABLE SOURCE TERMS INCLUDED IN PHASE AND Source Term Phase Phase Mill area included included Ore Pads included included Tailings Cell with Interim Soil included included 18 Source Term Phase Phase Cover Tailings Cell active interim soil cover included Interim soil cover Tailings Cell4A active active Tailings Cell4B excluded active The wind erosion and radon release rates from the tailings cells active and with interim soil cover were modeled by using 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 of uncovered 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 radon release rate of 20 pCilm2s 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 and with interim soil cover were assumed to occur over the entire area of each cell however only radon is released at 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 R313-15-3011a requirement that the dose to individual members of the public shall not exceed 100 mrem/yr radon included For processing Colorado Plateau ore the maximum total annual effective dose commitment was calculated by SENES to be maximum of 1.4 mremlyr for an infant at the nearest potential resident BHV-l Tables 6.1-1 and 6.1-3 of Appendix i.e effective dose and is about 1.4%of the R313-15-3011a limit of 100 mremlyr radon included to an individual member of the public for Phases and For processing Arizona Strip ore the total annual effective dose commitments were calculated by SENES to be maximum of 3.1 mrem/yr for an infant at the nearest potential resident BHV-l Tables 6.2-1 and 6.2-3 of Appendix i.e effective dose and is about 3.1%of the 100 mremlyr limit radon included to an individual member of the public for Phases and Overall the predicted annual effective dose commitments for Phases and and the proposed development of new tailings Cell 4B during anticipated ore processing operations comply with R313-15 In addition the MILDOS-AREA calculated 40 CFR 190 annual dose commitments excluding radon were compared to the 40 CFR 190 criterion which is 25 mremlyr to the whole body excluding the dose due to radon and 25 mremlyr to any other organ to any member of the public EPA 2002 The 40 CFR 190 doses were also used to demonstrate compliance with R313-15-1014 10 CFR 20.1101d 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 mremlyr absent of the radon dose For processing Colorado Plateau ore the 40 CFR 190 annual dose commitments were calculated by SENES to be maximum of 4.8 mremlyr for teenager at the nearest potential residence BHV-1 i.e dose 19 to the bone and is about 19%of the 40 CFR 190 dose criterion of 25 rnremlyr for Phases and Further the 40 CFR 190 annual effective dose commitments demonstrate compliance with the R313-15-1014 10 CFR 20.1101d limit of 10 mremlyr 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 mrenVyr for teenage at the nearest potential resident BHV-l i.e dose to the bone and is well within the 40 CFR 190 dose criterion of 25 rnremlyr for Phases and Further the annual effective dose commitments demonstrate compliance with R313-15-1014 10 CFR 20.1101d limit of 10 mremlyr 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 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 as Appendix to this Report 10.5 Reclamation of Cell 4B Cell 4B will be reclaimed in similar fashion to Cell 4A The final reclamation cover will be the same as the final reclamation cover for the other tailings cells including Cell 4A The Mills Reclamation Plan will be amended to specifically incorporate Cell 4B into the Reclamation Plan and the Mills financial surety will be updated accordingly 11.0 Alternatives The action under consideration is the construction of an already contemplated tailings Cell Cell 4B in order to accommodate continued operation of the Mill The alternatives available to the Executive Secretary are to Amend the License to include the construction of Cell 4B with its existing terms and conditions Amend the License to include the construction of Cell 4B with such additional conditions as are considered necessary or appropriate to protect public health safety and the environment or Deny the addition of Cell 4B 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 Mills 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 asserts that 20 alternatives with equal or greater impacts need not be evaluated and alternative is the appropriate alternative for selection 11.1 Issuance of Amendment for Cell 4B The Mill is one of only two operating uranium mills in the United States and the only uranium mill on the western slope of the Rocky Mountains As result the Mill is the only currently available opportunity for production of uranium from conventionally mined ore in San Juan County and in the four corners area of the United States The Mill therefore provides benefit to the regional community and to the uranium industry as whole in the United States The construction of Cell 4B as proposed 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 of the 2007 ER the Mills 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 the GWDP which provides additional protection for public health and the environment including rigorous groundwater monitoring program to monitor and assess the performance of tailings cells associated with the facility The Mill has demonstrate that it is capable of continuing to operate in manner that satisfies all regulatory standards and ALARA goals under the existing terms and conditions of the 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 result of Cell 4B construction 11.2 No Action Alternative no action alternative would result in the amendment request being denied and the immediately available processing opportunities 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 will severely constrain the utilization of the Mill in the near term and eliminate its ability to operate over the longer term during time when commodity prices for uranium are favorable and the demand for uranium milling capacity is conventionally mined ore for the recovery of uranium and the construction of Cell 4B will provide the opportunity for regular employment in an economically depressed area of the United States 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 21 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 Criterion 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 EAs performed by NRC in 1985 NRC 1985 and 1997 NRC 1997 in connection with previous License renewals and UDEQs approval of Cell 4B construction will satisfy applicable criteria in R313-22-33 and R313-24 Further the siting and use of Cell 4B have already been approved and are part of the License see the discussion in the Introduction above As result Denison asserts that the Executive Secretary should have no basis for denying the proposed action 11.3 Alternatives Considered But Eliminated Consideration of Alternative 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 different location Even if that were possible it has been demonstrated in Section of the 2007 ER is sited in good hydrogeologic setting and is otherwise well sited for its operations including tailings cells contemplated at the time of the Mills original licensure This is evident from the fact that the Mill has operated since its inception in compliance with applicable regulatory standards and ALARA goals See also Appendices and of the 1978 ER which address alternative tailings disposal systems and locations 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 construction that complies with the applicable siting requirements of 10 CFR Part 40 Appendix can be identified and obtained Even if suitable alternative site were to be identified and obtained licensing and construction of new mill and tailings cells could not be accomplished in time frame that would ensure production could commence in period of suitable market conditions Furthermore as the existing Mill tailings would have to be decommissioned in place creation of new mill site would result in unnecessary proliferation of mill tailings disposal facilities in contravention of 10 CFR Part 40 Appendix Criterion Consideration of Alternative Engineering Methods 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 of continuing to operate 22 under the existing terms and conditions of the License in manner that will continue to comply with such standards and goals Furthermore the Mills GWDP institutes additional protections and engineering controls including the requirement that any new construction of tailings 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 More specifically the proposed Cell 4B design is essentially the same as the design of Cell 4A which incorporates Best Available Technology and which has been approved by the Executive Secretary 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 License and the design of Cell 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 and the 1985 and 1997 EAs The activities contemplated with regard to ore processing and disposal of tailings remain unchanged from those previously authorized under the License 11.5 Comparison of the 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 of uranium mills has dwindled and the demand for uranium milling service capacity from local miners and the industry as whole has increased in 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 to NUREG 1569 requires that the applicant for license renewal describe any updates and changes to the economic costs and benefits for the facility since the last application 23 There have been no significant changes to the costs associated with the Mill since the last License renewal in 1997 While there will change to the currently disturbed area as result of the Cell 4B construction this additional Cell was contemplated described and assessed as critical component of the initial FES and attendant licensing of the facility As indicated in Section of the 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 of continuing 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 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 of the largest private employers in San Juan County The benefits of the Mill will continue to be the provision of well-paying jobs to workers in San Juan County and the support of the tax base in that County Moreover as the only operating uranium mill on the western slope of the 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 of uranium the need for continued licensing of the Mill is crucial for such miners and for the uranium industry in the United States as whole In sum the costs associated with the operation of the Mill have not changed significantly but the benefits have become more evident over time as the number of uranium mills has dwindled and the demand for uranium milling services from local miners and the industry as whole has increased 13.0 Mitigation of Impacts NUREG 1569 requires that the ER provide the results of effectiveness of any mitigation proposed and implemented in the original license In the case of the Mill there have not been any mitigations proposed or implemented under the License 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 Mills Reclamation Plau and the 2000 EA NRC 2000 prepared by the NRC in connection with the Reclamation Plan The Mills Reclamation Plan and financial surety arrangements as well as the provisions in the Mills GWDP that relate to final reclamation of the site are described in detail in Section of the February 2007 License Renewal Application and are incorporated here by reference The construction of Cell 4B will not result in any changes to operations at the Mill that would impact 24 decommissioning decontamination or reclamation aspects associated with Mill activities or the previous analyses of such aspects The grading contours and other reclamation features related to closure of Cell 4B at site closure are shown in Figure 13 All design features for Cell 4B are included in the Cell 4B Design Report White Mesa Mill Blanding Utah prepared by Geosyntec Consultants which was transmitted to UDEQ in December of 2007 25 15.0 References Dames Moore January 30 1978 Environmental Report White Mesa Uranium Project San Juan County Utah Denison Mines USA Corp February 28 2007 White Mesa Uranium Mill License Renewal Application State of Utah Radioactive Materials License No UT1900479 Denison Mines USA Corp February 28 2007 White Mesa Uranium Mill Environmental Report in Support of the License Renewal Application State of Utah Radioactive Materials License No UT1900479 Environmental Protection Agency EPA February 2002 Code of Federal Regulations Title 40 Part 190 Environmental Radiation Protection for Nuclear Power Operations Geosyntec Consultants December 2007 Cell 4B Design Report White Mesa Mill Blanding Utah Hydro Geo Chem Inc August 22 2002 Hydraulic Testing at the White Mesa Uranium Mill Near Blanding Utah During July 2002 Hydro Geo Chem Inc August 2005 Perched Monitoring Well Installation and Testing at the White Mesa Uranium Mill April Through June 2005 Hydro Geo Chem Inc January 2008 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 International Uranium USA Corporation and Hydro Geo Chem Inc November 2001 Update to Report Investigation of Elevated Chloroform Concentrations in Perched Groundwater at the White Mesa Uranium Mill Near Blanding Utah Knight-Piesold LLC November 23 1998 Evaluation of Potential for Tailings Cell Discharge White Mesa Mill MWH Americas Inc November 2007 Infiltration And Contaminant Transport Modeling Report White Mesa Mill Site Blanding Utah Denison Mines USA Corp NRC May 1979 Final Environmental Statement related to operation of White Mesa Uranium Project Energy Fuels Nuclear Inc Docket No 40-8681 NUREG-0556 Office of Nuclear Material Safety and Safeguards NRC September 26 1985 United States Nuclear Regulatory Commission Environmental Assessment Prepared by the Uranium Recovery Field Office in Consideration of the Renewal of Source Material License SUA-1358 for the Umetco Minerals Corporation White Mesa Uranium Mill 26 NRC Office of Nuclear Material Safety and Safeguards Division of Waste Management February 1997 Environmental Assessment for Renewal of Source Material License No SUA-1358 Energy Fuels Nuclear Inc White Mesa Uranium Mill San Juan County Utah NRC Division of Waste Management Office of Nuclear Material Safety and Safeguards February 10 2000 Environmental Assessment for International Uranium Corporations Uranium Mill Site White Mesa San Juan County Utah in Consideration of an Amendment to Source Material License SUA-1358 for the Approval of the Proposed Reclamation Plan NRC Division of Fuel Cycle Safety and Safeguards Office of Nuclear Material Safety and Safeguards August 22 2002 Environmental Assessment For International Uranium USA Corporations Uranium Mill Site White Mesa San Juan County Utah In Consideration of an Amendment to Source Material License SUA-1358 for the Receipt and Processing of the Maywood Alternate Feed NRC Division of Fuel Cycle Safety and Safeguards Office of Nuclear Material Safety and Safeguards June 2003 Standard Review Plan for In Situ Leach Uranium Extraction License Applications Final Report N1JREG-1569 SENES Consultants Limited February 2007 Dose Assessment in Support of the License Renewal Application Environmental Report for the White Mesa Uranium Mill SENES Consultants Limited April 2008 Proposed Development of New Tailings Cell 4Bfor the White Mesa Uranium Mill SENES Consultants Limited April 28 2008 Review of Environmental Radiological Monitoring Program for the White Mesa Uranium Mill TITAN Environmental Corporation July 1994 Hydrogeological Evaluation of White Mesa Uranium Mill TITAN Environmental Corporation September 1994 Points of Compliance White Mesa Uranium Mill Umetco Minerals Corporation and Peel Environmental Services 1993 Groundwater Study White Mesa Facilities Blanding Utah U.S Department of Commerce 1977 Climatic Atlas of the United States reprinted by the National Oceanic and Atmospheric Administration 1977 27 APPENDIX 28 APPENDIX 29 APPENDIX 30 Appendix 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 17th Street Denver Colorado 80265 303 628-7798 Prepared by HYDRO GEO CHEM INC 51 West Wetmore Suite 101 Tucson Arizona 85705-1678 520293-1500 January 2008 TABLE OF CONTENTS INTRODUCTION SITE HYDROGEOLOGY.3 2.1 Geologic Setting 2.2 Hydrogeologic Setting 2.3 Perched Zone Hydrogeology 2.3.1 Lithologic and Hydraulic Properties 2.3.1.1 Dakota 2.3.1.2 Burro Canyon 2.3.2 Perched Groundwater Flow 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 EVALUATION OF POTENTIAL FLOW PATHS AND TRAVEL TIMES FOR HYPOTHETICAL SEEPAGE ORIGINATING FROM CELL 15 4.1 Estimated Travel Time from the Base of Cell and Proposed Cell 4B to the Perched Zone 15 4.2 Estimated Travel Times from Tailings Cell and Proposed Cell 4B toRuinSpring 16 4.3 Estimated Total Travel Time from the Base of Tailings Cell and Proposed Cell 4B to Ruin Spring 17 RECOMMENDED ADDITIONAL PERCHED ZONE MONITOR1NG WELLS DOWNGRADIENT OF PROPOSED CELL 4B 21 REFERENCES 23 LIMITATIONS STATEMENT 25 TABLES Peel Hydraulic Test Results Results of July 2002 and June 2005 Hydraulic Tests 5ite Hydrogeology OW Travel Times Proposed Wells Cell 4B H\7 8000\celI4b\hydrcell4b.doc January 2008 TABLE OF CONTENTS Continued FIGURES Site Plan and Perched Well Locations Kriged Brushy Basin Contact Elevations Perched Water Levels August 1990 Perched Water Levels August 1994 Perched Water Levels September 2002 Kriged 3rd Quarter 2007 Water Levels Portion of USGS Black Mesa 7.5 Sheet Showing Approximate Location of Tailing Cells in Relation to Nearby Canyons and Ruin Spring Depth to Water 3rd Quarter 2007 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\71 8000\eell4b\hydreell4b.doe January 82008 ii INTRODUCTION This report provides 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 hypothetical conservative solute assuming no dispersion from existing tailings cell and proposed cell 4B at the site to downgradient discharge point Recommendations for additional perched zone monitoring wells downgradient of proposed cell 4B are also provided Figure is site plan showing the locations of perched monitoring wells and proposed cell 4B Tailings cell has been in service for many years and large quantity of groundwater monitoring and hydraulic test data exists for perched monitoring wells completed around the penmeter 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 and the discharge point Cell 4B is proposed to be installed at the downgradient edge of cell The data from the immediate vicinity and downgradient of cell used to compute rates of movement and travel times for hypothetical conservative solute will likewise be used to calculate travel times for the hypothetical solute from proposed cell 4B to the discharge point 5ite Hydrogeology OW Travel Times Proposed Wells Cell 4B H\71 8000\cell4b\hydrcell4b.doc January 82008 Site Hydrogeology GW Travel Times Proposed Wells Cell 4B H\7 8000\cell4b\hydrcell4b.doc January 2008 SITE IIYDROGEOLOGY Titan 1994 provides detailed description of site hydrogeology based on information available at that time brief summary of site hydrogeology that is based primarily on Titan 1994 but includes the results of more recent site investigations is provided below 2.1 Geologic Setting The White Mesa Uranium Mill site 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 undeformed The average elevation of the site is approximately 5600 feet 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 The alluvial materials consist mostly of aeolian silts and fme-grained aeolian sands with thickness varying from few feet to as much as 25 to 30 feet across the site The alluvium is underlain by the Dakota Sandstone and Burro Canyon Formation which are sandstones having total thickness ranging from approximately 100 to 140 feet Beneath the Burro Canyon Formation lies the Morrison Formation 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 Formation classified as shales are very fme-grained and have very low permeability The Brushy Basin Site Hydrogeology GW Travel Times Proposed Wells Cell 4B H\7 8000\eell4b\hydrcell4b.doe January 2008 Member is primarily composed of bentonitic mudstones siltstones and claystones The Westwater Canyon and Salt Wash Members also have 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 1000 to 1100 feet of materials having low average vertical permeability Groundwater within this system is under artesian pressure in the vicinity of the site is of generally good quality and is used as secondary source of water at the site 2.2 Hydrogeologic Setting The site is located within region that has 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 1200 feet below land surface makes access difficult The Navajo/Entrada aquifer is capable of yielding significant quantities of water to Site Hydrogeology OW Travel Times Proposed Wells Cell 4B H\7 8000\eell4b\hydreell4b.doe January 82008 wells hundreds of gallons per minute gpm Water in wells completed across these units at the site rises approximately 800 feet above the base of the overlying Summerville Formation Perched groundwater in the Dakota Sandstone and Burro Canyon Formation is used on limited basis to the north upgradient of the site because it is more easily accessible Water quality of the 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 of the perched zone to wells installed north of the site 2.3 Perched Zone Hydrogeology Perched groundwater beneath the site occurs primarily within the Burro Canyon Formation Perched groundwater at the site has generally low quality due to high total dissolved solids TDS in the range of approximately 1200 to 5000 milligrams per liter mg/L and is used primarily for stock watering and irrigation in the areas upgradient north of the site Perched water is supported within the Burro Canyon Formation by the underlying fine-grained Brushy Basin Member Figure is 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 5ite Hydrogeology OW Travel Times Proposed Wells Cell 4B H\7 8000\eell4b\hydreell4b.doe January 2008 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 LU Lithologic and Hydraulic Properties Although the Dakota Sandstone and Burro Canyon Formations are often described as single unit due to their similarity previous investigators at the site have distinguished between them The Dakota Sandstone is relatively-hard to hard generally fme-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 of the 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 Bmshy Basin Member 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 PiØsold 1998 Any fractures observed in cores collected from site borings are typically cemented showing no open space 5ite Hydrogeology GW Travel Times Proposed Wells Cell 4B H\71 8000\eell4b\hydreell4b.doe January 82008 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 percent The permeability of the Dakota Sandstone based on packer tests in borings installed at the site ranges from 2.71 10.6 centimeters per second cmls to 9.12 cmls with geometric average of 3.89 io5 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 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 of the Burro Canyon Formation ranges from 1.9 io7 to 1.6 10 cm/s with geometric mean of 1.1 if5 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-01 MW-03 MW-OS MW-17 MW-18 MW-19 MW- 20 and MW-22 during the week of July 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 5ite Hydrogeology OW Travel Times Proposed Wells Cell 4B H\7 8000\eell4b\hydrcell4b.doe January 82008 June 2005 yielded average perched zone permeabilities ranging from approximately o- cm/s to o4 cm/s similar to the range reported by previous investigators at the site Hydro Geo Chem Inc 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 o-7 to 10A cm/s Permeability estimates from these tests were based on pumping/recovery and slug tests analyzed using several different methodologies 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 relatively continuous zone of higher permeability International Uranium Corporation 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 and at MW-14 located on the downgradient edge of tailings cell of 1.4 l0 cm/s and 7.5 io4 cm/s respectively UMETCO 1993 may indicate that this zone extends beneath the southeastern margin of the cells This zone of higher 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 of cell 5ite Hydrogeology OW Travel Times Proposed Wells Cell 4B H\71 8000\eell4b\hydreell4b.doe January 2008 nor is it evident in wells MW-3 MW-5 MW-l2 MW-15 MW-16 MW-l7 MW-20 MW-21 or MW-22 located south to southwest downgradient of the tailings cells based on the lithologic logs or hydraulic testing of the 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 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 limited basis as water supply to the north upgradient of the site 23.2 Perched Groundwater Flow Perched groundwater flow at the site has historically been to the south/southwest Figures through 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 Site Hydrogeology GW Travel Times Proposed Wells Cell 4B H\7 8000\eelI4b\hydreell4bdoe Januaiy 82008 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 and 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 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 local steepening of groundwater gradients over portions of the site Conversely pumping of wells MW-4 TW4-19 TW4-20 and MW-26 has depressed the perched water table locally and reduced average hydraulic gradients to the south and southwest of these 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 of the 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 10000 feet south-southwest of tailings cell and is depicted on the USGS 7.5-minute quad sheet for Black Mesa Figure 5ite Hydrogeology GW Travel Times Proposed Wells Cell 4B H\71 8000\cell4b\hydreell4b.doc January 2008 10 PERCHED ZONE HYDROGEOLOGY BENEATH AND DOWNGRADIENT OF THE TAILINGS CELLS Perched water as of the 3rd Quarter 2007 was encountered at depths of approximately 57 to 115 feet bis in the vicinity of the tailings cells at the site Figure Beneath tailings cell depths to water ranged from approximately 77 feet below top of casing btoc in the eastern portion of the cell at MW-25 to approximately 114 feet btoc at the southwest margin of the cell at MW-23 Assuming an average depth of the base of tailings cell 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 similar assumption can be made for proposed cell 4B 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 feet in the southwest portion of the site Figure Beneath tailings cell the saturated thickness varies from approximately 49 feet in the eastemmost corner of the cell to approximately feet in the western portion of the cell South-southwest of the tailings cells the saturated thickness ranges from less than foot at MW-2 to approximately 26 feet 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-iS MW 17 and MW-20 is approximately 14 feet The average saturated thickness based on measurements at MW-5 MW-is MW-3 and MW-20 which lay close to line between the center of tailings cell and Ruin Spring is approximately 12 feet By projecting conditions at Site Hydrogeology GW Travel Times Proposed Wells Cell 4B H\71 8000\cell4b\hydrcell4b.doc January 82008 11 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 10000 feet south-southwest of the cells Perched zone hydraulic gradients currently range from maximum of approximately 0.05 feet per foot ft/ft east of tailings cell to approximately 0.01 ft/ft downgradient of cell between cell and MW-20 The average hydraulic gradient between the downgradient edge of tailings cell and Ruin Spring can be approximated assuming the following The elevation of Ruin Spring based on the USGS topographic map for Black Mesa is approximately 5390 feet amsl The distance between the downgradient edge of tailings cell and Ruin Spring is approximately 10000 feet The average groundwater elevation at the downgradient edge of tailings cell is approximately 5510 feet amsl Site Hydrogeology OW Travel Times Proposed Wells Cell 48 H\71 8000\eell4b\hydreell4b.doe January 82008 12 Using these assumptions the average perched zone hydraulic gradient between tailings cell and Ruin Spring is approximately 55105390 0.012fl/fi 10000 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 The elevation of the base of tailings cell which is also the approximate pre-existing land surface elevation near the center of the cell is approximately 5580 feet amsl Under these conditions for an unconfmed perched zone the maximum possible average perched zone hydraulic gradient between tailings cell and Ruin Spring would be approximately 55805390 o.019fl/fl 10000 Although the downgradient edge of proposed cell 4B is closer to Ruin Spring approximately 9000 feet from Ruin Spring rather than about 10000 feet the above hydraulic gradient calculations can also be applied to cell 4B 3.3 Permeability The average permeability of the perched zone downgradient of tailings cell 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 Peel conducted hydraulic tests at perched zone wells MW-il MW-12 MW-14 and MW-iS in 1992 UIMETCO 1993 Site Hydrogeology GW Travel Times Proposed Wells Cell 4B H\71 8000\eell4b\hydreell4b.doe January 2008 13 Results of these tests are provided in Table HGC conducted slug tests at perched zone wells MW-3 MW-5 MW-l7 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 which is based on Table of HGC 2002 and Table of HGC 2005 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-il MW-12 MW-14 and MW-15 with the HGC KGS results for wells MW-3 MW-5 MW-i7 MW-20 MW-22 and MW-25 yields geometric average of 2.3 io5 cmls and similarly averaging the Peel test results with the HGC Bouwer-Rice results yields geometric average of 4.3 cmls as shown in Table The early time results at MW-S using the Bouwer-Rice solution from Table of HGC 2002 were used in the computations to yield conservatively high estimate of permeability 5ite Hydrogeology OW Travel Times Proposed Wells Cell 4B H\7 8000\eell4b\hydreell4b.doe Januaiy 82008 14 EVALUATION OF POTENTIAL FLOW PATHS AND TRAVEL TIMES FOR HYPOTHETICAL SEEPAGE ORIGINATING FROM CELL Although more than 25 years of groundwater monitoring at the site has shown no impact to perched water from the tailings cells an evaluation of hypothetical transport of conservative solute in seepage from existing cell and proposed cell 4B is presented assuming flow path from the base of the existing and proposed cells to the perched water and thence to Ruin Spring Average travel times for conservative constituent moving from the base of tailings cell 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 of MW- 16 and MW-17 and from the Burro Canyon Formation during drilling of MW-16 4.1 Estimated Travel Time from the Base of Cell and Proposed Cell 4B to the Perched Zone Knight-PiØsold estimated maximum volumetric seepage rate for tailings cell based on cell construction and liner characteristics of approximately 80 cubic feet per day ftlday or 0.42 gpm over the entire cell Knight-PiØsold 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 fmal cover is emplaced Assuming cell footprint of 3.38 106 ft2 this rate is equivalent to 2.37 i05 ft/day or 0.0086 feet per year ft/yr Site Hydrogeology OW Travel Times Proposed Wells Cell 4B H\71 8000\eell4b\hydrcell4b.doc January 82008 15 The average rate of downward movement of conservative solute dissolved in the seepage assuming no dispersion an average water saturation of 0.20 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.OOS6flIyr 0.24fl/yr .20 18 The average time to travel 70 feet to the perched water zone would then be approximately 290 years This is conservative estimate because the average water saturations would be likely to increase thereby reducing the downward rate of travel and increasing the travel time Assuming 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 However for purposes of calculation potential seepage rates and downward rates of movement for hypothetical conservative solute will be assumed to be the same for cell 4B as those calculated for cell 4.2 Estimated Travel Times from Tailings Cell and Proposed Cell 4B to Ruin Spring Under current conditions the average hydraulic gradient between the downgradient edge of tailings cell to Ruin Spring is estimated to be 0.012 as discussed in Section 3.2 Assuming the following 5ite Hydrogeology GW Travel Times Proposed Wells Cell 4B H\71 8000\eell4b\hydreell4b.doe January 2008 16 Average porosity 0.18 Average hydraulic gradient 0.0 12 Flow path length 10000 feet Average permeability range 2.3 iO5 to 4.3 i0 cm/s 0.064 ftlday 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 ftlday to 0.0080 fllday or 1.6 ftlyr to 2.9 ftyr The estimated average travel time for conservative solute assuming no dispersion from tailings cell to Ruin Spring would then be approximately 6250 to 3450 years over this range of permeabilities Under conditions of the maximum possible average perched groundwater gradient of 0.019 ft/fl 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 4055 to 2160 years For proposed cell 4B which is about 9000 feet from Ruin Spring the estimated travel times would be approximately 5625 to 3100 years using the gradient of 0.012 and approximately 3650 to 1950 years using the gradient of 0.019 4.3 Estimated Total Travel Time from the Base of Tailings Cell and Proposed Cell 4B to Ruin Spring The total average travel time for conservative solute from the base of tailings cell or proposed cell 4B to Ruin Spring under current conditions would be the sum of the travel time from the base of either cell to the perched water table and the time to travel within the 5ite Hydrogeology GW Travel Times Proposed Wells Cell 4B H\71 8000\eell4b\hydrcell4b.doe January 2008 17 perched zone to Ruin Spring Based on the estimates provided in Sections 4.1 and 4.2 the total average travel time of conservative solute assuming no dispersion over the range of average permeability estimates would be between 6540 and 3740 years for cell and between 5915 and 3390 years for proposed cell 4B assuming an average hydraulic gradient of 0.0 12 ftlft As discussed in Section 4.1 because the rate of movement of conservative solute from the base of cell 4B would likely be slower than for cell 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 or cell 4B and Ruin Spring as discussed in Section 3.2 or as result of reduced vadose zone travel times due to development of relatively large leak in either cell Under hypothetical conditions in which relatively large leak were to develop potentially reducing vadose zone travel times to only few years the vadose zone travel time could be ignored and the total average travel time assuming no dispersion would range from approximately 6250 to 3450 years for cell and between 5625 and 3100 years for proposed cell 4B assuming an average hydraulic gradient of 0.0 12 ftlft Under hypothetical conditions in which the average perched zone hydraulic gradient between either cell and Ruin Spring reached 0.019 ft/ft which also implies negligible vadose zone travel time the total average travel time assuming no dispersion over the estimated range in permeability would be between approximately 4055 and 2160 years for cell and between 3650 and 1950 years for cell4B 5ite Flydrogeology OW Travel Times Proposed Wells Cell 4B H\71 8000\eell4b\hydrcell4b.doe January 82008 18 Estimates based on hypothetical assumptions of relatively large leak in tailings cell or an average hydraulic gradient as high as 0.019 ft/ft 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 cell 4B than for cell 5ile Hydrogeology GW Travel Times Proposed Wells Cell 4B H\7 8000\cell4b\hydrcell4b.doc January 2008 19 Site Hydrogeology GW Travel Times Proposed Welts Cell 48 H\7t 8000\eell4b\hydreetl4b.doe January 82008 20 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 of the 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 MVsT30 functions as downgradient well for cell and as an upgradient well for cell Wells MW-5 MW-12 and MW-23 that currently function as downgradient wells for cell 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 of tailings 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 corner of proposed cell 4B and one between the southwest corner well and existing well MW-15 These installations would conservatively maintain the approximate existing spacing as defmed 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-2 would continue to function as distal downgradient wells for the entire cell 5ite Hydrogeology OW Travel Times Proposed Wells Cell 48 H\71 8000\cell4b\hydrcell4b.doc January 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 5ite Hydrogeology OW Travel Times Proposed Wells Cell 4B H\71 8000\eelI4b\hydreell4b.doe January 2008 22 REFERENCES Bouwer and R.C Rice 1976 slug test method for determining hydraulic conductivity of unconfined aquifers with completely or partially penetrating wells Water Resources Research Vo 123 Pp 423-428 Hyder J.J Butler C.D McElwee and Liu 1994 Slug tests in partially penetrating wells Water Resources Research Vol 3011 Pp 2945-2957 Hydro Geo Chem 2001 Update to report Investigation of Elevated Chlorofonn 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-PiØsold 1998 Evaluation of Potential for Tailings Cell Discharge White Mesa Mill Attachment Groundwater Information Report White Mesa Uranium Mill Blanding Utah Submitted to UDEQ TITAN 1994 Hydrogeo logical Evaluation of White Mesa Uranium Mill Submitted to Energy Fuels Nuclear UMETCO 1993 Groundwater Study White Mesa Facilities Blanding Utah Prepared by UIMETCO Minerals Corporation and Peel Environmental Services US EPA 1992 EPA RCRA Ground-Water Monitoring Draft Technical Guidance November 1992 5ile Hydrogeology GW Travel Times Proposed Wells Cell 4B H\7 8000\eell4b\hydreell4b.doe January 82008 23 Site Hydrogeology GW Travel Times Proposed Wells Cell 4B H\71 8000\eell4b\hydreell4b.doe January 82008 24 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 HGC 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 HGCs 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 HGC makes no representation as to the accuracy or completeness of any information provided by other parties not under contract to HGC to the extent that HGC 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 if modified or if used by third parties shall be at the sole risk of the user Site Flydrogeology GW Travel Times Proposed Wells Cell 4B H\71 8000\eell4b\hydreell4b.doe January 2008 25 Site Flydrogeology OW Travel Times Proposed Wells Cdl 4B H\71 8000\cell4b\hydrcell4b.doc January 2008 26 TABLES TABLE Peel Hydraulic Test Results Well Hydraulic Conductivity cm/c MW-il 1.4x103 MW-12 2.2x105 MW-14 7.5x io MW-15 1.9x1O Notes From UMETCO 1993 H\71 8000\cell4b\Tables.xls Table /8/2008 TABLE Results of July 2002 and June 2005 Hydraulic Tests Well Permeability in centimeters per second KGS Bouwer-Rice MW-3 4.0x107 1.5x105 MW-5 3.5 1O 2.4 io MW-17 2.6 io5 2.7 io5 MW-20 --93 1O MW-22 1.Ox1O 7.9x106 MW-25 1.1 x104 7.4x105 Geometric Average of above test results with Peel3 test results for MW-Il MW-12 MW-14 andMW-15 2.3x105 4.3x105 Notes From HGC 2002 HGC 2005 From UMETCO 1993 H\71 8OOOcell4b\Tables.xIs Table 1/8/2008 FIGURES EXPLANATiON perched moriieorirg well temporary perched monhoring well perched piezomeler perched monitoring well Jeieealled April 2005 temporary perched monitoring well Installed April2005 T37S T38S 1trW4.ll 01W4-13 Tw4-7rl.e O1W4.i OlW44orwl_u 01W4.e wildlife pond // // // // // // SITE PLAN AND PERCHED WELL LOCATIONS WHITE MESA SITE 1/4/2008 H/71 8000/cell4b/welloc.srf MW-21 perched morriloring well showing 44t elevallon in feel emel temporary perched monilering well showig eleyalhn In feel aesl perched piezomeler showing elevation in feel sins perched lTionilOnng well installed showing elevelion in feel sinS temporary perched reioriloring well inslall KRIGED BRUSHY BASIN CONTACT ELEVATIONS WHITE MESA SITE 911912007 118000/cefl4bJbbeIO7O5sif 1-JYDRO GEO CHEM INC PERCHED WATER LEVELSAUGUST199 OOO FAorovs Dots 1Aisi IDot Rs.ecc mc SS Ol/3Ob31 71s00101 EXPLANATION PERCHED MONITORING WELL SHOWING WATER LEVEL IN FEET AMSL WILDLIFE POND _____WATER LEVEL CONTOUR UNE DASHED WI-IERE UNCERTAIN SCALE IN FCET PERCHED MONITORING WELL SEIOWNO WATER LEVEL IN FEET AMSL WLDLIFE PONO 5550 5540 SS553O 5520 5510 44 5500 EXPLANATION MW-3 5471 Vt 5460 5450 Kfl 5445 58O .._WATER LEVEL CONTOUR LINE DASHED WHERE UNCERTAIN TEMPORARY PERCHED MONITORING WELL SHOWING WATER LEVEL IN FEET AMSL PIEZOMETER SHOWING WATER LEVEL IN FEET AMSL 38o _____WATER LEVEL CONTOUR LINE DASHED WHERE UNCERTAIN WATER LEVELS FOR PIEZOMETERS ARE FROM AUGUSt 2002 5460 5450 47 747PERCHEDMONITORING WELL SHOWING WATER LEVEL IN FEET AMSL PIA NAT ID perched rnoniroring well alioirirg elevation rn feel amer temporary perched rnonrlontg well ahoMng elevelion in leer anal perched piezomelrr ahoirdag elevatIon in leer axial perched monItoring well installed Aplil 2005 showing elevation in leer axial leniporary perched monitoring well inslalled April 2005 showIng elevation in leer amsl rensporery perched rnonilodog well installed .2007 showing approximate elevation // // NOTES Locations and elevations for TW4-23 1W4-24 and TW4-25 are approximate Water revel for MW-26 TW4-1 is from the second quarter 2007 UYDRO CEO CHEM INC KRIGED 3rd QUARTER 2007 WATER LEVELS WHITE MESA SITE POR11ON OF USGS BLACK MESA 7.5 SHEET SHOWiNG APPROXIMATE LOCATION OF TAILING CELLS RELATION TO NEARBY CANYONS ANO RUIN SPRING perched monitoring well showing depth in feet temporary perched rronitodng we0 showing doper In feat perched piezomneter ehowtng depth Infect perched monitoring welt installed April 2005 sitowing depth In feet temporary perched maccoring well Installed Apnl 2005 showing depth in feet Oee PIEZ5 .47 T37S T38S // // // // NOTES Locations of TW4-23 TW4-24 and TW4-25 are approximale Measurement for MW-26 TW4-151 is from the second quarter 2001 HYDRO CEO CUEM INC DEPTHS TO WATER 3rd QUARTER 2007 WHITE MESA SITE temporary parched monitoring well Installed May 2007 showing depth In feet 1/4/2008 H1718000/c.li4b/dtw080l.srf perched alonhoring watt showing sattireted thickness feet temporary perched mondoting watt showing saturated thickness feat perched piezometershowitig saturated thickness feet perched monitoting watt trtstatted Aprit 2005 stsowitg saturated tttiokntssfeet temporary perched monitoting watt installed Apsit 2005 showIng saturated thickness feet temporary perched rnondoring watt Itatatted May 2007 showIng aetarated thickness teat 025 022 T38S // // // // // // // NOTES Locattons and values for TW4-23 TW4-24 and TW4-25 are approximate Value for MW.26 TW4-15 is based on tha second quarter 2007 water level HYDRO CEO CHEM INC APPROXIMATE SATURATED THICKNESS 3rd QUARTER 2007 WHITE MESA SITE 11412008 H17180001c114b/satdthck.stl CTWMiw4.i4 01W4-6 T37S T38S wildlife pond new temporary perched reoniloring well Installed May2007 localions epproximelel SITE PLAN SHOWING EXISTING AND PROPOSED PERCHED WELL LOCATIONS WHITE MESA SITE H/71 8000lcell4bfpropwell.srf Appendix 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 MB 3N4 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 referred to as the millin San Juan County Utah approximately miles 9.6 km south of the city of Blanding The mill is located on parcel of land and mill site claims covering approximately 5415 acres 2191 ha 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 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 50 mile 80 km radius for processing of conventional ores The assessment was prepared for scenarios in which Colorado Plateau 0.25%U308 and 1.5%V205 or Arizona Strip 0.637%U308 and no V205 ores are processed at the mill This dose assessment extends the analyses of the 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 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 and 4A to reflect the current operational status of the 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 involves the continued use of Cell for solution evaporation the continued use of Cell for solution evaporation and the disposal of tailings solids and the use of Cell 4A for disposal of tailings solids and solution evaporation Phase occurs after Cell is ftill and is no longer an active cell During Phase Cells 4A and 4B are used for disposal of tailings solids and solution evaporation and Cell is used for solution evaporation In each Phase Cell with interim soil cover over the entire cell area is included in the model and in Phase Cell 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 50 mile 80 1cm 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 from 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 April 2008 ES-i SENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill and added to the dose from the mill area and ore pads Table ES-i provides summary of the source terms included in Phases and of the development of new tailings cells TABLE ES-i SOURCE TERMS INCLUDED IN PHASES AND Source Term Phase Phase Mill area included included Ore Pads included included Tailings Cell with Interim Soil Cover included included Tailings Cell active interim soil cover Tailings Cell 4A active active Tailings Cell 4B excluded active The wind erosion and radon release rates from the tailings cells active and with interim soil cover were modelled by using 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 61.252b Subpart since it is not possible to predict the distribution of uncovered tailings between the active cells at any given time As 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 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 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 from the tailings cells and with interim soil cover were assumed to occur over the entire area of each cell however only radon is released at 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-iS-3011a requirement that the dose to individual members of the public shall not exceed 100 mremlyr radon included For the processing of Colorado Plateau ore the maximum total annual effective dose commitments was calculated to be maximum of 1.4 mrenilyr 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%of the R3 13-15-3011 limit of 100 mremlyr radon included to an individual member 34489-10 FINAL April 2008 ES-2 5ENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill of the public for Phases and For the processing of Arizona Strip ore the total annual effective dose commitments were calculated to be maximum of 3.1 mremlyr for an infant at the nearest potential resident BHV-1 Tables 6.2-1 and 6.2-3 i.e effective dose and is about 3.1%of the 100 mremlyr limit radon included to an individual member of the public for Phases and Overall using conservative assumptions the predicted annual effective dose commitments for Phases and comply with R313-l5 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 mremlyr 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 R313-15-1014 10 CFR 20.1101d 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 mremyrabsent of the radon dose For the processing of Colorado Plateau ore the 40 CFR 190 annual dose commitments were calculated to be maximum of 4.8 mremlyr for teenager at the nearest potential resident BHV-l 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 and Further the 40 CFR 190 annual effective dose commitments demonstrate compliance with the R313-15-10l4 10 CFR 20.1101d ALARA goal of 10 mremiyr 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 and was 0.545 mremyr for an infant at BHV-l.For Arizona Strip ore the 40 CFR 190 annual dose commitments were at most 12 mremyrfor teenager at the nearest potential resident BHV-1 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 mremlyr for Phases and Further the 40 CFR 190 annual effective dose commitments demonstrate compliance with the R313-15-1014 10 CFR 20.1101d 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 and was 1.39 mrem/yr for an infant at BHV-Overall using conservative assumptions ore processing in Phases and comply with the requirements of 40 CFR 190 and the ALARA goal set out in R313 -15-1014 34489-10 FINAL April 2008 ES-3 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE OF CONTENTS Page No EXECUTIVE SUMMARY ES-i ACRONYMS ABBREVIATIONS AC-i 1.0 iNTRODUCTION 1-i 1.1 Background 1-i 1.2 Objective 1-2 1.3 Approach 1-2 1.4 Contents Of This Report 1-3 2.0 REGULATORY COMPLIANCE 2-1 3.0 RADIATION DOSE ASSESSMENT 3-1 3.1 General Information About MILDOS-AREA 3-1 3.2 The Use of MILDOS-AREA In This Assessment 3-1 4.0 SOURCETERMS 4-1 4.1 Point Sources 4-3 4.1.1 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 OrePads 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-i 6.0 RADIATION DOSE ESTIMATES 6-1 6.1 MILDOS-AREA Results For Colorado Plateau Ore 6-2 6.1.1 R3 13-15-3011a 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 R3i3-i5-30i la Regulatory Compliance 6-19 6.2.2 40 CFR 190 Regulatory Compliance 6-26 7.0 KEY OBSERVATIONS 7-i 8.0 REFERENCES 8-1 34489-10 FINAL April 2008 5ENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill LIST OF APPENDICES Page No APPENDIX HISTORY OF MILDOS A-l APPENDIX EMISSION CALCULATIONS BA B.l Calculation of Annual Dust Loss B-l B.2 Emission Calculations B-2 APPENDIX MILDOS-AREA RESULTS CA C.l MILDOS-AREA Results for Colorado Plateau Ore C-l C.l.1 R313-15-301 la Regulatory Compliance C-l C.2 MILDOS-AREA Results for Arizona Strip Ore C-7 C.2.1 R313-15-301 la Regulatory Compliance C-7 34489-10 FINAL April 2008 11 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill LIST OF TABLES Page No ES-i Source Terms Included in Phases and ES-2 1.3-1 Source Terms Included in Phases and 1-3 4.2-i Characteristics of Tailings Cells in Phase 4-6 4.2-2 Characteristics of Tailings Cells in Phase 4-6 4.5-i Radioactive Particulate 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 1-Comparison of Annual Dose Commitments with Applicable Radiation Protection Standards Colorado Plateau Ore 6-3 6.1-2 Phase 1-Total Annual Dose Commitments for Meat Ingestion Pathway Colorado Plateau Ore mremlyr 6-6 6.1-3 Phase 2-Comparison of Annual 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 mremlyr 6-9 6.1-5 Phase i-Comparison of 40 CFR19O Annual Dose Commitments with Applicable Radiation Protection Standards Colorado Plateau Ore 6-10 6.1-6 Phase 1-40 CFR1 90 Annual Dose Commitments for Meat Ingestion Pathway Colorado Plateau Ore mremlyr 6-13 6.1-7 Phase 2-Annual Population Dose Commitments within 50 miles 80 1cm of the Mill for Colorado Plateau Ore 6-13 6.1-8 Phase 2-Comparison of 40 CFR1 90 Annual Dose Commitments with Applicable Radiation Protection Standards Colorado Plateau Ore 6-15 6.1-9 Phase 2-40 CFR1 90 Annual Dose Commitments for Meat Ingestion Pathway Colorado Plateau Ore mremyr 6-18 6.1-10 Phase 2-Annual Population Dose Commitments within 50 miles 80 1cm of the Mill for Colorado Plateau Ore 6-18 6.2-1 Phase i-Comparison of Annual Dose Commitments with Applicable Radiation Protection Standards Arizona Strip Ore 6-20 6.2-2 Phase 1-Total Annual Dose Commitments for Meat Ingestion Pathway Arizona Strip Ore mremlyr 6-23 6.2-3 Phase 2-Comparison of Annual Dose Commitments with Applicable Radiation Protection Standards Arizona Strip Ore 6-23 6.2-4 Phase 2-Total Annual Dose Commitments for Meat Ingestion Pathway Arizona Strip Ore mremlyr 6-26 6.2-5 Phase i-Comparison of 40 CFR19O Annual Dose Commitments with Applicable Radiation Protection Standards Arizona Strip Ore 6-27 34489-10 FINAL April 2008 111 SENES Consultants Limited Proposed Development ofNew Tailings Cell 4Bfor White Mesa Uranium Mill LIST OF TABLES Page No 6.2-6 Phase 1-40 CFR19O Annual Dose Commitments for Meat Ingestion Pathway Arizona Strip Ore mremlyr 6-30 6.2-7 Phase 1-Annual Population Dose Commitments within 50 miles 80 1cm of the Mill for Arizona Strip Ore 6-30 6.2-8 Phase 2-Comparison of 40 CFR19O Annual Dose Commitments with Applicable Radiation Protection Standards Arizona Strip Ore 6-31 6.2-9 Phase 2-40 CFR19O Annual Dose Commitments for Meat Ingestion Pathway Arizona Strip Ore mrem/yr 6-34 6.2-10 Phase 2-Annual Population Dose Commitments within 50 miles 80 1cm of the Mill for Arizona Strip Ore 6-34 7-1 Source Terms Included in Phases and 7-1 Parameter Values for Calculation of Annual Dusting Rate for Exposed Tailings B-i C.1-l Annual Dose Commitments Colorado Plateau Ore C-i 1-2 40 CFR 190 Annual Dose Commitments Colorado Plateau Ore C-4 C.2-i Annual Dose Commitments Arizona Strip Ore C-7 C.2-2 40 CFR 190 Annual Dose Commitments Arizona Strip Ore C-10 LIST OF FIGURES Page No 4.1 Source Locations 4-2 5.1 Receptor Locations 5-2 34489-10 FINAL April 2008 iv SENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill ACRONYMS ABBREVIATIONS ALC Allowable Concentration ANL Argonne National Laboratory ALARA As Low As Reasonably Achievable Avg average ASCII American Standard Code for Information Interchange Bi-2 10 bismuth-2 10 Bi-2 14 bismuth-2 14 CCD Counter Current Decantation CFR Code of Federal Regulations Ci curie DCF Dose Conversion Factor DRC State of Utah Division of Radiation Control DUSA Denison Mines USA Corp EPA United States Environmental Protection Agency Ew Process Emission Factor Radon Release Rate FES Final Environmental Statement F5 annual frequency of occurrence of wind group ft feet ft3 cubic feet grams ore grams of ore GPS Global Positioning System GUI Graphical User Interface ha hectares hr hours ICRP International Commission on Radiological Protection ID Induced Draft lbs pounds km kilometers kts knots NESHAPs National Emission Standards for Hazardous Air Pollutants NRC United States Nuclear Regulatory Commission NUREG Regulatory Guide meters m2 square meters mrem millirem MPC Maximum Permissible Concentration 34489-10 FENAL April 2008 AC-i SENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill Pb-2 10 lead-2 10 Pb-214 lead-214 pCi picocurie Po-2 10 polonium-2 10 Po-2 18 polonium-2 18 Ra-226 radium-226 Rn-222 radon-222 Resuspension rate for wind group seconds Radionuclide Emission Rate SENES Specialists in Energy Nuclear and Environmental Sciences TGLM Task Group on Lung Dynamics Lung Model Th-230 thorium-230 tpy tons per year U308 triuranium octoxide Yellowcake Unat natural uranium U-234 uranium-234 U-235 uranium-235 U-238 uranium-238 V205 vanadium pentoxide yd3 cubic yards yr year 34489-10 FINAL April 2008 AC-2 SENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor 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 millin San Juan County Utah approximately miles 9.6 km south of the city of Blanding The mill is located on parcel of land and mill site claims covering approximately 5415 acres 2191 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 authority over the mill was assumed by the State of Utah Division of Radiation Control DRC at that time The mill is 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 further processed for recovery of vanadium before recycling NRC 1979 In the early 990s 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 of currently available alternate feed material is completed DUSA 2007a In February 2007 SENES prepared 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 50 mile 80 1cm radius for the processing of Colorado Plateau or Arizona Strip ores separately MILDOS-AREA is an NRC approved code designed as 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 0.2 5%U305 and 1.5%17205 NRC 1980 The vanadium content in the ore is further processed for recovery before recycling Arizona Strip ore contains 0.637%U308 and no vanadium Landau 2007 34489-10 FINAL April 2008 1-1 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill The activity concentrations of U-238 in Colorado Plateau and Arizona Strip ore were 700 and 1783 pCi U-238/g ore respectively The proposed ore process rate was assumed to be 730000 tons per year tpy an average of 2000 tons per day Therefore assuming that the average uranium recovery would be at the historical recovery yield of 94%approximately 1715 tons 3431000 lbs of U308 per year would be recovered from Colorado Plateau ore at the proposed ore process rate Similarly approximately 4371 tons 8742000 lbs of U308 per year would be recovered from Arizona Strip ore at the proposed ore process rate 1.2 OBJECTIVE The objective of this report is to extend the analyses of the 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 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 and 4A to reflect the current operational status of the site including the re-commissioning of Cell 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 potentially be received by individuals and the general population within 50 mile 80 1cm 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 from 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 involves the continued use of Cell for solution evaporation the continued use of Cell for solution evaporation and the disposal of tailings solids and the use of Cell 4A for disposal of tailings solids and solution evaporation Phase occurs after Cell is fill and is no longer an active cell Phase involves the use of Cell for solution evaporation and Cells 4A and 4B for disposal of tailings solids and solution evaporation In each Phase Cell with interim soil cover over the entire cell area is included in the model and in Phase Cell 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 referred to as Scenario and respectively Each scenario/ore was analyzed with the following separate MILDOS-AREA runs 34489-10 FINAL April 2008 1-2 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill Tailing Cell with Interim Soil Cover Tailings Cell with Interim Soil Cover Tailings Cell 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 of tailings cells to the mill area and ore pads for the two anticipated development Phases Table 1.3-1 provides summary of the source terms included in Phases and of the development of new tailings cells TABLE 1.3-1 SOURCE TERMS INCLUDED IN PHASES AND Source Term Phase Phase Mill area included included Ore Pads included included Tailings Cell with Interim Soil Cover included included Tailings Cell active interim soil cover Tailings Cell 4A active active Tailings Cell 4B excluded active 1.4 CONTENTS OF THIS REPORT The remainder of this report is arranged into seven sections Section 2.0 Regulatory Compliance provides description of the regulatory framework pertaining 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 of the public and how MILDOS-AREA was used Section 4.0 Source Terms describes the source terms 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 34489-10 FINAL April 2008 1-3 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill Section 5.0 Receptors describes the receptors used in the MILDOS-AREA runs 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 summary of the dose estimates for the two Phases in each scenario Section 8.0 References provides list of reference material used to prepare this report Appendix History of MILDOS-AREA describes how the MILDOS-AREA software has evolved highlighting some of the key differences between the updated version MILDO S-AREA ANL 1998a and the original version of MILDOS Appendix Emissions Calculations describes the basis of the emission estimates for each source Appendix MILDOS-AREA Results provides the dose estimates for MILDOS-AREA runs for the mill area including the ore pads and each tailings cell 34489-10 FINAL April 2008 1-4 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor 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 R3 13-15-1012 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 of the public that are as low as reasonably achievable ALARA Under R3 13-15-3011 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 year including radon exclusive of the dose contribution from natural background and medical sources Under 10 CFR 20.1301 NRC 1991 NRC has adopted the provisions of the 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 mremlyr to the whole body 75 mremyrto the thyroid and 25 mremlyr to any other organ of any member of the public radon and it daughters excepted In addition 10 CFR 20.1301 R3 13-15-1014 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 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill 3.0 RADIATION 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 from uranium milling operations the radioactivity contribution from the U-235 chain is less than 5%of that from the U-238 chain The particulate 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-210 and Po-210 The model accounts for the releases and in-growth of other radionuclides using the assumption of secular equilibrium within the U-238 decay chain The transport of model radiological emissions from the point and area sources is predicted using 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 particulates 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 of meat and vegetables 3.2 TuE USE OF MILDOS-AREA IN Tuis 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 2.20f3 ANL l998a 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 scenario/ore Information about the history of MILDOS-AREA is provided in Appendix In Scenario 1715 tons 3430100 lbs of U308 per year of Colorado Plateau ore would be recovered at the proposed ore process rate of 730000 tpy assuming that the average uranium recovery is 94%Similarly in Scenario 4371 tons 8742000 lbs of U308 per year of Arizona Strip ore would be recovered In order design 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 34489-10FINAL-April2008 3-1 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill reference point The coordinates of 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 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 from 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 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 34489-10 FINAL April 2008 3-2 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor 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 and area source dusting from ore pad stockpiles and the tailings cells As mentioned in Section 3.2 all source terms 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 northing and elevation of each source relative to 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 Earth of all sources used in this assessment 34489-10 FINAL April 2008 4-1 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill ERGURE 41 SOURCE LOCATIONS 44S9 10 FINAL April ThUR 4-2 SENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor 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-23 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%V205 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 all source terms are provided in Appendix 4.1 POINT SOURCES Mill point sources used in this assessment include the grinder loading ore to the grizzly and yellowcake stacks north and south The vanadium stack described in Section 4.1.4 is exclusive to the processing of Colorado Plateau ore 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 of the ore only wet grinding operation The ore dust emissions are controlled 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-23 and its decay daughters assuming secular equilibrium would be emitted at 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 Ci/yr for Colorado Plateau and Arizona Strip ore respectively 4.1.2 Grizzly The emissions from trucks dumping ore onto the grizzly are highly controlled the truck dump area is enclosed on three sides and has negative pressure on it during dumping activities The ore is delivered wet with an average moisture content of 10%The exhaust from the induced draft ID fans used on the grizzly is ducted through baghouse EnecoTech 1991a and 1991b 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 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 5ENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill 4.1.3 Yellowcakc Stacks The mill has two yellowcake dryers north and south yellowcake dryers From the EnecoTech analysis stack tests on the yellowcake dryer yielded yellowcake emission rate of 0.06 lbs/hr U308 when the process rate was 1300 lbs/hr This yields an emission rate of 0.092 lbs/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 rate of .O1E-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-2l0 are processed along with yellowcake at 0.22%0.13%and 0.78% ofU-238 respectively EnecoTech l991a and l991b Therefore the decay daughters Th-230 Ra-226 and Pb-210 are emitted at rate of 2.22E-05 1.3lE-05 and 7.88E-05 Ci/yr respectively for Colorado Plateau ore Similarly the decay daughters Th-230 Ra-226 and Pb-2l0 are emitted at rate of 5.67E-05 3.35E-05 and 2.O1E-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 recycled to the counter-current decantation step or further processed for recovery of vanadium before recycling The product from the vanadium recovery contains less than 0.005%U308 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 rate of 1.01 E-06 Ci/yr Based on the EnecoTech 1991a and 1991b measurements for the decay daughters of U-238 Th-230 Ra-226 and Pb-210 processed along with yellowcake of 0.22%0.13% and 0.78%of U-23 respectively the emissions from the remaining radionuclides were assumed to be negligible and in any event would likely be discharged to the tailings cells 34489-10 FINAL April 2008 44 5ENE5 Consultants Limited Proposed Development of New 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 description of the 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 of emissions namely unloading ore from trucks to the ore pad and wind emissions Approximately 300000 tons of ore were assumed to be temporarily stockpiled at the mills ore pads at any given time Using bulk ore density of 1.47 tons/yd3 DUSA Feb 6/07 the quantity of ore would create pile 30 ft 9.1 tall covering approximately acres 17000 m2 stockpile area With respect to the truck unloading emissions process emission factor of 0.04 lbs of ore is emitted per cubic yard handled for truck end and assuming no control NRC 1987 and 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 rate of .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 50%control factor due to the active watering program in place EnecoTech 1991a and 1991b 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 g/m2yr this was calculated using the method from NRC Regulatory Guide 3.59 NRC 1987 on the basis of the meteorological data provided by DUSA Turk 2007b presented in Appendix the annual dust loss from the ore pads is 10%that of the tailings piles since the particulates in the ore pads are coarse material to 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 rate of 3.l7E-04 and 8.07E-04 Ci/yr for Colorado Plateau and Arizona Strip ore respectively Therefore the total emission rate of U-23 and its daughter from truck dumping and wind erosion is 1.61E-02 and 4.lOE-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 34489-10 FINAL April 2008 4-5 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill 4.2.2 Tailings Cells The characteristics of each tailings cell included in Phases and of the proposed development of new 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 Tailings Cell Interim Soil Cover Inactive Active 4A 4B TABLE 4.2-2 CHARACTERISTICS OF TAILINGS CELLS IN PHASE Tailings Cell Interim Soil Cover Inactive Active 4A 4B Active Tailings Cells Wind erosion of tailings and radon release rates from the active tailings cell were estimated using 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 maximal worst case approach The following assumptions were used for the active tailings cells Each tailings cell was assumed to have maximum area of 10 acres for uncovered tailings material this assumptions is considered to be conservative because the average area of uncovered tailings in cell is expected to be less than 10 acres Wind-eroded tailings dust would arise from the 10 acres of uncovered tailings The total annual radon release rate for each tailings cell was calculated by assuming radon release rate of 20 pCi/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 was assumed to be 70 acres while tailing cells 4A and 4B were assumed to be 40 acres each 34489-10 FINAL April 2008 4-6 5ENES Consultants Limited Proposed Development ofNew Tailings Cell 4Bfor White Mesa Uranium Mill Using the onsite wind data generated over the last three years provided by DUSA Turk 2007b the annual dust loss from the tailings cells was estimated to be approximately 213 gm2yr this was calculated using the method from NRC Regulatory Guide 3.59 NRC 1987 An average uranium recovery rate of 94%was assumed In addition process emission control factor of 70%was assumed based on the active watering tailings solutions spraying program on exposed areas of tailings beaches in active areas solutions cover other tailings areas and crusting agents from the sprayed solutions act to minimize the erosion of the tailings beaches by wind EnecoTech l99la and l991b With these assumptions and the particulate emission factor U-23 would be emitted at rate of 2.71E-04 Ci/yr and the decay daughters Th-230 Ra-226 and Pb-2l0 would be emitted at rate of 4.52E-03 Ci/yr from each active cell for Colorado Plateau ore These total annual emission rates assume operation at the proposed ore process rate of 730000 tpy and an ore specific activity of 700 pCi/g Similarly for Arizona Strip ore U-238 is emitted at rate of 6.9lE-04 Ci/yr and the decay daughters Th-230 Ra-226 and Pb-2 10 are emitted at rate of 1.1 5E-02 Ci/yr from each active cell These total annual emission rates assume the proposed ore process rate of 730000 tpy and an ore specific activity of 1783 pCi/g In this assessment the total annual radon release rates for active tailings cell and 4A and 4B were estimated to be 179 Ci/yr for tailings cell and 102 Ci/yr for each of tailings cells 4A and 4B 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 confirmed that the 20 pCi/m2s release rate utilized for this assessment is conservative estimate Interim Soil Cover Inactive Tailings Cells The tailings cells and 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 with interim soil cover is 66.8 acres The area of tailings cell with interim soil cover is 70 acres nominal value of 10 pCi/m2s was used for radon flux based on historical values for the Mills tailings cells and No tailings dust will be released Using the assumptions above the total annual radon release from the tailings cells and with interim soil covers were 85.3 and 89.4 Ci/yr respectively 34489-10 FINAL April 2008 4-7 SENE5 consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill 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 joint frequency distribution which is required input for MILDOS-AREA The joint frequency distribution used in this assessment was provided by DUSA Turk 2007b using the most recent three years 2004 to 2006 of recorded 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 65000 residents and local demographics have experienced little change since the 2000 census 34489-10 FINAL April 2008 4-8 5ENES Consultants Limited Pr o p o s e d D e v e l o p m e n t of Ne w Ta i l i n g s Ce l l 4B f o r Wh i t e Me s a Ur a n i u m Mi l l 4. 5 UR A N I U M MI L L SO U R C E EM I S S I O N RA T E S 4. 5 . 1 Co l o r a d o P l a t e a u Or e Th e ca l c u l a t e d mi l l ra d i o a c t i v e pa r t i c u l a t e an d ra d o n em i s s i o n ra t e s fr o m po i n t so u r c e s an d ar e a s o u r c e s de s c r i b e d in Se c t i o n s 4. 1 an d 4. 2 re s p e c t i v e l y fo r Co l o r a d o Pl a t e a u or e a r e pr o v i d e d in Ta b l e 4. 5 - 1 TA B L E 4. 5 - 1 RA D I O A C T I V E PA R T I C U L A T E AN D R A D O N EM I S S I O N RA T E S CO L O R A D O PL A T E A U OR E Gr i n d i n g Or e Du m p to Gr i z z l y Or e Pa d s No r t h YC St a c k So u t h YC St a c k In t e r i m So i l Co v e r Ac t i v e Va n a d i u m St a c k b Ta i l i n g s Ce l l Ta i l i n g s Ce l l Ta i l i n g s Ce l l Ta i l i n g s Ce l l 4A Ta i l i n g s Ce l l 4B Em i s s i o n Ra t e Ci l y r U- 2 3 8 9. 2 7 E - 0 5 9 . 2 7 E - 0 5 l. 6 1 E - 0 2 l. O 1 E - 0 2 l . O 1 E - 0 2 O. O O E O O O . O O E O O 2. 7 1 E - 0 4 2. 7 1 E - 0 4 2 . 7 1 E - 0 4 1 . O 1 E - 0 6 Th - 2 3 0 9. 2 7 E - 0 5 9 . 2 7 E - O 5 1. 6 1 E M 2 2. 2 2 E 0 5 2. 2 2 E M 5 O. O O E O O O . O O E O O 4. 5 2 E 0 3 4. 5 2 E M 3 4. 5 2 0 3 2. 2 2 E 0 9 Ra - 2 2 6 9. 2 7 E - 0 5 9 . 2 7 E - 0 5 1 . 6 1 E - 0 2 1 . 3 1 E - 0 5 l. 3 1 E - 0 5 O. O O E O O O . O O E O O 4. 5 2 E - 0 3 4 . 5 2 E - 0 3 4 . 5 2 E - 0 3 1 . 3 1 E - 0 9 Pb - 2 1 0 9. 2 7 E - 0 5 9 . 2 7 E - 0 5 1 . 6 1 E - 0 2 7 . 8 8 E - 0 5 7 . 8 8 E - 0 5 O. O O E O O O . O O E O O 4. 5 2 E - 0 3 4 . 5 2 E - 0 3 4 . 5 2 E - 0 3 7 . 8 8 E - 0 9 Rn - 2 2 2 9. 2 7 E O 1 No t e 3. 7 5 E 0 2 No t e N o t e 8. 5 3 E O 1 8. 9 4 E O 1 1. 7 9 E 0 2 1 . 0 2 E 0 2 1 . 0 2 E 0 2 No t e No t e s No si g n i f i c a n t re l e a s e du r i n g th i s pr o c e s s So u r c e is ex c l u s i v e to th e pr o c e s s i n g of Co l o r a d o Pl a t e a u or e 4. 5 . 2 Ar i z o n a St r i p Or e Th e ca l c u l a t e d mi l l ra d i o a c t i v e pa r t i c u l a t e an d ra d o n em i s s i o n ra t e s fr o m po i n t so u r c e s an d ar e a s o u r c e s de s c r i b e d in Se c t i o n s 4. 1 an d 4. 2 re s p e c t i v e l y fo r Ar i z o n a St r i p or e a r e pr o v i d e d in Ta b l e 4. 5 - 2 34 4 8 9 - 1 0 - - F I N A L Ap r i l 20 0 8 4- 9 5E N E 5 Co n s u l t a n t s L i m i t e d Pr o p o s e d D e v e l o p m e n t of Ne w Ta i l i n g s Ce l l 4B f o r Wh i t e Me s a Ur a n i u m Mi l l TA B L E 4. 5 - 2 RA D I O A C T I V E PA R T I C U L A T E AN D R A D O N EM I S S I O N RA T E S AR I Z O N A ST R I P OR E Gr i n d i n g Or e Du m p to Gr i z z l y Or e Pa d s No r t h YC St a c k So u t h YC St a c k In t e r i m So i l Co v e r Ac t i v e Ta i l i n g s Ce l i Ta i l i n g s Ce l l Ta i l i n g s Ce l l Ta i l i n g s Ce l l 4A Ta i l i n g s Ce l i 4B Em i s s i o n Ra t e Ci l y r U- 2 3 8 2 . 3 6 E - 0 4 2 . 3 6 E - 0 4 4 . 1 O E - 0 2 2. 5 8 E - 0 2 2 . 5 8 E - 0 2 O. O O E O O O . O O E O O 6. 9 1 E - 0 4 6 . 9 1 E - 0 4 6 . 9 1 E - 0 4 Th - 2 3 0 2 . 3 6 E - 0 4 2 . 3 6 E - 0 4 4 . 1 O E - 0 2 5. 6 7 E - 0 5 5 . 6 7 E - 0 5 O. O O E O O O . O O E O O 1. 1 5 E - 0 2 1 . 1 5 E - 0 2 1 . 1 5 E - 0 2 Ra - 2 2 6 2 . 3 6 E - 0 4 2 . 3 6 E - 0 4 4. 1 O E - 0 2 3. 3 5 E - 0 5 3 . 3 5 E - 0 5 O. O O E O O O. O O E O O 1. 1 5 E - 0 2 1. 1 5 E - 0 2 1. 1 5 E - 0 2 Pb - 2 1 0 2 . 3 6 E - 0 4 2 . 3 6 E - 0 4 4 . 1 O E - 0 2 2 . O 1 E - 0 4 2. O 1 E - 0 4 O. O O E O O O . O O E O O 1. 1 5 E - 0 2 1 . 1 5 E - 0 2 1 . 1 5 E - 0 2 Rn - 2 2 2 2. 3 6 E 0 2 No t e 9. 5 6 E 0 2 No t e N o t e 8. 5 3 E O 1 8 . 9 4 E O 1 1 . 7 9 E 0 2 1 . 0 2 E 0 2 1 . 0 2 E 0 2 No t e No si g n i f i c a n t re l e a s e du r i n g th i s pr o c e s s 34 4 8 9 - 1 0 FI N A L - Ap r i l 2 0 0 8 4- 1 0 SE N E S Co n s u l t a n t s L i m i t e d Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill 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- White Mesa Ute Community Blanding Utah In addition two grazing locations and were considered as possible source of meat As mentioned in Section 3.2 the receptor locations were determined using GPS coordinates provided by DUSA Turk 2007a The GPS coordinates were used for all the receptors except for Grazing locations and where the easting and northing for Grazing locations and 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 34489-10 FINAL April 2008 5-1 SENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill FIGURE Si RECEPTOR LOCATIONS Receptor Legend White Mesa Community Nearest Potential Resident BHV Nearest Historical Resident BHV Nearest Actual Resident Bland ng Grazing Location Grazing Location 44X9-lO FINAl April 700X -2 SENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill 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 of the Mill near the location of air monitoring station BHV-The nearest actual resident is located approximately 1.6 miles 2.5 1cm north of the mill Nearby population groups include the community of White Mesa about 8.5 km south east and the city of Blanding approximately miles 10 1cm from the mill The area to the immediate north of the mill Grazing location is believed to be used only for grazing of meat animals beef NRC 1979 second location Grazing location 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 l991b Although considered unlikely in one worst case scenario it is possible that the meat animals grazed at Grazing location and would be eaten by the residents near the mill scenario which supports dairy cattle grazing at Grazing locations and was not included because the prospect of supporting dairy cattle in those locations is not credible given the arid climate and the much larger feed requirements of dairy cattle as opposed to beef cattle DUSA has also indicated that there are no dairy cattle grazed in Grazing locations and 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 or This is thought to be very conservative assumption 3448 9-10 FINAL April 2008 5-3 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill 6.0 RADIATION DOSE ESTIMATES This section describes the MILDOS-AREA results of the mills 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 13-15 requirements that the dose to individual members of the public shall not exceed 100 mremlyr radon included In addition MILDOS-AREA calculates 40 CFR 190 doses excludes radon The 40 CFR 190 Criterion is 25 mremlyr to the whole body excluding the dose due to radon and 25 mremyrto any other organ to any member of the public EPA 2002 The 40 CFR 190 doses were also used to demonstrate compliance with 10 CFR 20.1101d R3 13-15-1014 Under 10 CFR 20.1101d R3 13-15-1014 the licensee must demonstrate as an ALARA goal that the total effective dose equivalent to the individual member of the public likely to receive the highest total effective dose equivalent will not exceed 10 mremlyr absent of the radon dose In this assessment worst-case scenario in which there is possibility that individuals near the mill ingest meat from cattle grown at Grazing Location or was considered It was assumed that the cattle will graze at Grazing location or for two months of the year due to the arid nature of the region and the lack of forage Therefore the meat ingestion dose to individuals near the mill who might consume beef grazed at Grazing Location or was assumed to be one- 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 dose commitments were estimated for locations in which individual members of the public might reside Nearest Potential Resident BHV-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 and are provided in Sections 6.1 and 6.2 for Colorado Plateau 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 and are provided in Sections 6.1 and 6.2 respectively 34489-10 FINAL April 2008 6-1 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill 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 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 R3 13-15-301 1a Regulatory Compliance The MILDOS-AREA calculated total annual dose commitments including radon for Phases and are provided in this section These doses are regulated by R3 13-15-3011 which requires that the dose to an individual member of the public shall not exceed 100 mremlyr radon included Phase Table 6.1-1 presents summary of the individual dose commitments for the residential receptors for the age group of infant child teenage and adult for Phase 34489-10 FINAL April 2008 6-2 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE 6.1-1 PHASE 1-COMPARISON OF ANNUAL DOSE COMMITMENTS TO APPLICABLE RADIATION PROTECTION STANDARDS COLORADO PLATEAU ORE AgeLocation Group Organ Estimated Dose mrem/yr Applicable Limit mremlyr Fraction of Limit Infant Effective 1.37E00 100 l.37E-02 Bone .92E00 Avg Lung 5.31E-0l Bronchi 1.30E01 Child Effective 1.05E00 100 1.05E-02 Bone l.37E00 Avg Lung 7.1OE-01 Potential Bronchi 1.30E01 BHV-Teenage Effective 1.1 OE00 100 1.1 OE-02 Bone 4.84E00 Avg Lung 5.68E-01 Bronchi 1.30EOl Adult Effective 9.84E-01 100 9.84E-03 Bone 2.13E00 Avg Lung 3.97E-01 Bronchi l.30E01 Infant Effective 3.lOE-01 100 3.1OE-03 Bone 3.05E-01 Avg Lung l.06E-01 Bronchi 3.52E00 Child Effective 2.66E-01 100 2.66E-03 Bone 2.33E-01 Avg Lung l.29E-01 Historical Bronchi 3.52E00 BHV-2 Teenage Effective 2.72E-01 100 2.72E-03 Bone 7.63E-01 Avg Lung 1.05E-01 Bronchi 3.52E00 Adult Effective 2.55E-01 100 2.55E-03 Bone 3.53E-Ol Avg Lung 7.69E-02 Bronchi 3.52E00 34489-10 FINAL April 2008 6-3 SENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE 6.1-1 ContcI PHASE 1-COMPARISON OF ANNUAL DOSE COMMITMENTS TO APPLICABLE RADIATION PROTECTION STANDARDS COLORADO PLATEAU ORE AgeLocation Group Organ Estimated Dose mrem/yr Applicable Limit mrem/yr Fraction of Limit Infant Child Actual Resident Teenage Adult Effective 8.78E-01 100 8.78E-03 Bone 1.13E00 Avg Lung 3.17E-01 Bronchi 8.78E00 Effective 6.95E-01 100 6.95E-03 Bone 8.12E-01 Avg Lung 4.21E-01 Bronchi 8.78E00 Effective 7.21E-01 100 7.21E-03 Bone 2.83E00 Avg Lung 3.39E-01 Bronchi 8.78E00 Effective 6.55E-01 100 6.55E-03 Bone 1.26E00 Avg Lung 2.40E-0l Bronchi 8.78E00 Infant Child Mesa Teenage Adult Effective 2.45E-01 100 2.45E-03 Bone 1.45E-01 Avg Lung 6.72E-02 Bronchi 3.18E00 Effective 2.25E-01 100 2.25E-03 Bone 1.08E-01 Avg Lung 6.47E-02 Bronchi 3.1 8E00 Effective 2.26E-01 100 2.26E-03 Bone 2.86E-01 Avg Lung 5.26E-02 Bronchi 3.18E00 Effective 2.20E-01 100 2.20E-03 Bone 1.48E-01 Avg Lung 4.27E-02 Bronchi 3.18E00 34489-10 FINAL April 2008 6-4 SENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE 6.1-1 Contd PHASE 1-COMPARISON OF ANNUAL DOSE COMMITMENTS TO APPLICABLE RADIATION PROTECTION STANDARDS COLORADO PLATEAU ORE Location Age Group Organ Estimated Dose mrem/yr Applicable Limit mremlyr Fraction of Limit Blanding Infant Effective .07E-0 100 .07E-03 Bone 8.94E-02 Avg Lung 3.36E-02 Bronchi .25E00 Child Effective 9.38E-02 100 9.38E-04 Bone 6.78E-02 Avg Lung 3.91E-02 Bronchi .25E00 Teenage Effective 9.SSE-02 100 9.55E-04 Bone 2.1OE-01 Avg Lung 3.23E-02 Bronchi 1.25E00 Adult Effective 9.08E-02 100 9.08E-04 Bone 1.OOE-01 Avg Lung 2.47E-02 Bronchi .25E00 From Table 6.1-1 the total annual effective dose commitments are at most 1.4%effective dose for infant at BHV-1 of the R313-15-3011a limit of 100 mrem/yr radon included to an individual member of the public Therefore the predicted annual effective dose commitments comply with R313-15-3011a In the worst case scenario in which there is possibility that individuals near the mill ingest meat from cattle grown at Grazing Location or It was assumed that the cattle will graze at Grazing location or for months of the year The meat ingestion dose to individuals near the mill who might consume beef grazed at Grazing Location or was assumed to be one-sixth of the MILDOS-AREA calculated meat ingestion dose from these grazing locations Table 6.1-2 presents summary of the annual dose commitments from the meat ingestion pathway for Grazing location and Even in the very unlikely event that resident were to consume meat from one of the grazing locations the total dose would remain well below regulatory limits 34489-10 FINAL April 2008 6-5 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE 6.1-2 PHASE 1-TOTAL ANNUAL DOSE COMMITMENTS FOR MEAT INGESTION PATHWAY COLORADO PLATEAU ORE mremlyr Location Age Group Organb Effectiv Bon Avg Lnnga Grazing Location Infant 0.OOE00 0.OOE00 0.OOE00 Child 1.08E-02 5.40E-02 4.91E-02 Teenage .70E-02 2.80E-0 4.30E-02 Adult .23E-02 .52E-0 .55E-02 Grazing Location Infant 0.OOE00 0.OOE00 O.00E0O Child 7.35E-04 3.65E-03 3.12E-03 Teenage l.14E-03 l.92E-02 2.72E-03 Adult 8.13E-04 1.OlE-02 2.25E-03 Note Assumes cattle will graze at the particular Grazing location for months of the year Phase Table 6.1-3 presents summary of the individual dose commitments for the residential receptors for the age group of infant child teenage and adult for Phase TABLE 6.1-3 PHASE 2-COMPARISON OF ANNUAL DOSE COMMITMENTS TO APPLICABLE RADIATION PROTECTION STANDARDS COLORADO PLATEAU ORE AgeLocation Group Organ Estimated Dose mremlyr Applicable Limit mremlyr Fraction of Limit Infant Effective 1.35E00 100 l.35E-02 Bone 1.90E00 Avg Lung 5.20E-01 Bronchi 1.28E0l Child Effective l.04E00 100 1.04E-02 Bone 1.35E00 Avg Lung 6.93E-01 Potential Bronchi .28E0 BHV-1 Teenage Effective 1.08E00 100 l.08E-02 Bone 4.75E00 Avg Lung 5.54E-Ol Bronchi 1.28EOl Adult Effective 9.68E-01 100 9.68E-03 Bone 2.09E00 Avg Lung 3.87E-01 Bronchi l.28E01 34489-10 FINAL April 2008 6-6 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE 6.1-3 Contd PHASE 2-COMPARISON OF ANNUAL DOSE COMMITMENTS TO APPLICABLE RADIATION PROTECTION STANDARDS COLORADO PLATEAU ORE Age Group Organ Estimated Dose mrem/yr Applicable Limit mrein/yr Fraction of Limit Infant Child Historical BHV-2 Teenage Adult Effective 3.1 OE-0 100 3.1 OE-03 Bone 3.03E-01 Avg Lung 1.05E-01 Bronchi 3.52E00 Effective 2.66E-01 100 2.66E-03 Bone 2.31E-01 Avg Lung 1.28E-01 Bronchi 3.52E00 Effective 2.72E-0l 100 2.72E-03 Bone 7.57E-01 Avg Lung 1.04E-01 Bronchi 3.52E00 Effective 2.55E-01 100 2.55E-03 Bone 3.50E-Ol Avg Lung 7.63E-02 Bronchi 3.52E00 Infant Child Actual Teenage Adult Effective 8.70E-01 100 8.70E-03 Bone 1.12E00 Avg Lung 3.11E-01 Bronchi 8.69E00 Effective 6.88E-01 100 6.88E-03 Bone 7.98E-01 Avg Lung 4.13E-01 Bronchi 8.69E00 Effective 7.13E-01 100 7.13E-03 Bone 2.78E00 Avg Lung 3.32E-Ol Bronchi 8.69E00 Effective 6.48E-01 100 6.48E-03 Bone 1.23E00 Avg Lung 2.35E-Ol Bronchi 8.69E00 34489-10 FINAL April 2008 6-7 SENES Consultants Limited Proposed Development ofNew Tailings Cell 4Bfor White Mesa Uranium Mill TABLE 6.1-3 Contd PHASE 2-COMPARISON OF ANNUAL DOSE COMMITMENTS TO APPLICABLE RADIATION PROTECTION STANDARDS COLORADO PLATEAU ORE AgeLocation Group Organ Estimated Dose mrem/yr Applicable Limit mrem/yr Fraction of Limit Infant Child Mesa Community Teenage Adult Effective 2.47E-01 100 2.47E-03 Bone 1.45E-01 Avg Lung 6.69E-02 Bronchi 3.20E00 Effective 2.26E-01 100 2.26E-03 Bone 1.07E-01 Avg Lung 6.45E-02 Bronchi 3.20E00 Effective 2.28E-01 100 2.28E-03 Bone 2.85E-01 Avg Lung 5.25E-02 Bronchi 3.20E00 Effective 2.22E-01 100 2.22E-03 Bone 1.48E-01 Avg Lung 4.27E-02 Bronchi 3.20E00 Infant Child Teenage Adult Effective 1.08E-01 100 1.08E-03 Bone 8.94E-02 Avg Lung 3.36E-02 Bronchi 1.26E00 Effective 9.46E-02 100 9.46E-04 Bone 6.79E-02 Avg Lung 3.92E-02 Bronchi 1.26E00 Effective 9.62E-02 100 9.62E-04 Bone 2.1OE-01 Avg Lung 3.23E-02 Bronchi 1.26E00 Effective 9.l5E-02 100 9.15E-04 Bone l.OOE-01 Avg Lung 2.48E-02 Bronchi 1.26E00 From Table 6.1-3 the total annual effective dose commitments are at most 1.4%effective dose for infant at BHV-of the R3 13-15-3011 limit of 100 mremlyr radon included to an individual member of the public Therefore the predicted annual effective dose commitments comply with R313-15-3011a In addition Table 6.1-4 presents summary of the annual dose commitments from the meat ingestion pathway for Grazing location and As before in the very unlikely event that 34489-10 FINAL April 2008 6-8 5ENE5 Consultants Limited Proposed Development of New Tailings cell 4Bfor 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 mrem/yr Location Age Group Organb Effectiv Bon Avg Lunga Grazing Location Infant O.OOEOO O.OOEOO O.OOEOO Child 1.07E-02 5.35E-02 4.87E-02 Teenage .68E-02 2.78F-O 4.26E-02 Adult .22E-02 .50E-O 3.5 1E-02 Grazing Location Infant O.OOEOO O.OOEOO O.OOEOO Child 6.73E-04 3.34E-03 2.82E-03 Teenage .04E-03 .76E-02 2.46E-03 Adult 7.41E-04 9.22E-03 2.03E-03 Assumes cattle will graze at the particular Grazing location for months of the 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 mrenVyr 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 R3 13-15-1014 10 CFR 20.1101d The licensee must demonstrate as an ALARA goal 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 mremlyr absent of the radon dose Phase Table 6.1-5 presents summary of the 40 CFR 190 individual dose commitments for residential receptors for the age group of infant child teenage and adult for Phase Note 34489-10--FINAL April 2008 6-9 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE 6.1-5 PHASE 1-COMPARISON OF 40 CFR 190 ANNUAL DOSE COMMITMENTS WITH APPLICABLE RADIATION PROTECTION STANDARDS COLORADO PLATEAU ORE AgeLocation Group Organ Estimated Dose mremlyr Applicable Limit mremlyr Fraction of Limit Infant Child Potential BHV Teenage Adult Effective 5.45E-O1 25 2.18E-02 Bone 1.86EOO 25 7.45E-02 Avg Lung 4.85E-O1 25 1.94E-02 Bronchi 9.73E-04 no limit given Effective 2.32E-O1 25 9.28E-03 Bone 1.33EOO 25 530E-02 Avg Lung 6.62E-Ol 25 2.65E-02 Bronchi 9.73E-04 no limit given Effective 2.76E-O 25 1.1 OE-02 Bone 4.79EOO 25 l.92E-Ol Avg Lung 5.22E-O1 25 2.09E-02 Bronchi 9.73E-04 no limit given Effective 1.63E-O1 25 6.SOE-03 Bone 2.09EOO 25 8.35E-02 Avg Lung 3.5lE-O1 25 1.40E-02 Bronchi 9.73E-04 no limit given Infant Child Historical BHV2 Teenage Adult Effective 8.07E-02 25 3.23E-03 Bone 2.82E-O1 25 l.13E-02 Avg Lung 8.56E-02 25 3.42E-03 Bronchi .39E-04 no limit given Effective 3.61E-02 25 l.44E-03 Bone 2.09E-Ol 25 8.37E-03 Avg Lung 1.07E-Ol 25 4.29E-03 Bronchi .39E-04 no limit given Effective 4.26E-02 25 1.71 E-03 Bone 7.30E-O1 25 2.92E-02 Avg Lung 8.31E-02 25 3.32E-03 Bronchi .39E-04 no limit given Effective 2.55E-02 25 .02E-03 Bone 3.26E-Ol 25 l.30E-02 Avg Lung 5.62E-02 25 2.25E-03 Bronchi .39E-04 no limit given 34489-10 FENAL April 2008 6-10 SENES Consultants Limited Proposed Development ofNew Tailings Cell 4Bfor White Mesa Uranium Mill TABLE 6.1-5 Contd PHASE 1-COMPARISON OF 40 CFR 190 ANNUAL DOSE COMMITMENTS WITH APPLICABLE RADIATION PROTECTION STANDARDS COLORADO PLATEAU ORE Age Group Organ Estimated Dose mrem/yr Applicable Limit mrem/yr Fraction of Limit Infant Child Resident Teenage Adult Effective 3.17E-O1 25 1.27E-02 Bone l.09EOO 25 4.37E-02 Avg Lung 2.81E-O1 25 1.12E-02 Bronchi 5.62E-04 no limit given Effective .35E-O1 25 5.40E-03 Bone 7.73E-Ol 25 3.09E-02 Avg Lung 3.84E-Ol 25 1.54E-02 Bronchi 5.62E-04 no limit given Effective .60E-O 25 6.42E-03 Bone 2.78EOO 25 1.11E-O1 Avg Lung 3.02E-O1 25 1.21E-02 Bronchi 5.62E-04 no limit given Effective 9.46E-02 25 3.78E-03 Bone 1.21EOO 25 4.86E-02 Avg Lung 2.03E-O1 25 8.12E-03 Bronchi 5.62E-04 no limit given Infant Child Commumty Teenage Adult Effective 3.36E-02 25 1.35E-03 Bone 1.19E-O1 25 4.74E-03 Avg Lung 4.55E-02 25 1.82E-03 Bronchi 4.25E-05 no limit given Effective l.31E-02 25 5.22E-04 Bone 7.80E-02 25 3.12E-03 Avg Lung 3.85E-02 25 1.54E-03 Bronchi 4.25E-05 no limit given Effective l.38E-02 25 5.51E-04 Bone 2.31E-Ol 25 9.26E-03 Avg Lung 2.72E-02 25 .09E-03 Bronchi 4.25E-05 no limit given Effective 8.69E-03 25 3.48E-04 Bone 1.llE-O1 25 4.42E-03 Avg Lung 1.91E-02 25 7.63E-04 Bronchi 4.25E-05 no limit given 34489-10 FINAL April 2008 6-11 SENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE 6.1-5 Contd PHASE 1-COMPARISON OF 40 CFR 190 ANNUAL DOSE COMMITMENTS WITH APPLICABLE RADIATION PROTECTION STANDARDS COLORADO PLATEAU ORE Age Group Organ Estimated Dose mremlyr Applicable Limit mrem/yr Fraction of Limit Infant Child Teenage Adult 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 .49E-05 no limit given Effective 9.23E-03 25 3.69E-04 Bone 5.38E-02 25 2.15E-03 Avg Lung 2.69E-02 25 1.08E-03 Bronchi .49E-05 no limit given Effective .06E-02 25 4.24E-04 Bone l.81E-O1 25 7.25E-03 Avg Lung 2.05E-02 25 8.19E-04 Bronchi 3.49E-05 no limit given Effective 6.38E-03 25 2.55E-04 Bone 8.16E-02 25 3.27E-03 Avg Lung 1.39E-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 BHV-1 of the 40 CFR 190 dose criterion of 25 mremlyr In addition the 40 CFR 190 annual effective dose commitments demonstrate compliance with the R3 13-15- 1014 10 CFR 20.1101d 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 was 0.545 mremlyr infant at BHV-1 or 5.45%of the 10 mremyrgoal In addition Table 6.1-6 presents summary of the 40 CFR 190 annual dose commitments from the meat ingestion pathway for Grazing Locations and As before in the unlikely event receptor were to eat meat from cattle grazing in areas or the total dose would remain well below regulatory limits 34489-10 FINAL April 2008 6-12 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE 6.1-6 40 CFR 190 ANNUAL DOSE COMMITMENTS FOR MEAT INGESTION PATHWAY COLORADO PLATEAU OREmrem/yr Location Age Group Effectivea Bon Avg Lunga Grazing Location Infant O.OOEOO O.OOEOO O.OOEOO Child 1.08E-02 5.40E-02 4.91E-02 Teenage .70E-02 2.80E-O 4.30E-02 Adult 1.23E-02 1.52E-Ol 3.55E-02 Grazing Location Infant O.OOEOO O.OOEOO O.OOEOO Child 7.33E-04 3.63E-03 3.lOE-03 Teenage 1.1 3E-03 1.9 lE-02 2.72E-03 Adult 8.1OE-04 1.O1E-02 2.24E-03 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 1-ANNUAL POPULATION DOSE COMMITMENTS WITHIN 50 MILES 80 km OF THE MILL FOR COLORADO PLATEAU ORE Organ ANNUAL POPULATION DOSE COMMITMENTS PERSON-REM PER YEAR Mill_Operations Effective Bone Avg Lung Bronchi 1.47E-O1 1.12EOO 1.53E-Ol 8.60EOO The population dose arising from processing Colorado Plateau ore during Phase 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 NCRP 1987 Cosmic and Cosmogenic Terrestrial Inhaled Radon Ingested Total Average 28 mremlyr 28 mremlyr 200 mremlyr 40 mremlyr 296 mremlyr 96 mrem/yr excluding radon Note Assumes cattle will graze at the particular Grazing location for months of the year Exclusive of radon 34489-10 FINAL April 2008 6-13 5ENE5 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 mremyr Of this 142 mremlyr 68 mrem/yr came from cosmic radiation while 74 mremlyr came from terrestrial radiation Dames Moore 1978 At the Hanksville site the corresponding average dose equivalent was about 122 mremlyr 68 mremlyr from cosmic radiation and 54 mremlyr from terrestrial radiation Dames Moore 1978 Ingested radionuclides would contribute about further 18 mremlyr NRC 1979 This brings the total background dose from external radiation and ingested radioactivity but exclusive of the 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 from radon of about 200 mrem per year is added then the total dose from natural background in the area of the mill is 360 mrem/yr or more assuming the dose from radon would increase along with that from terrestrial source The current population of San Juan County is about 14400 people Assuming everyone living in San Juan County receives an annual dose of about 360 mremlyr 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 Table 6.1-8 presents summary of the 40 CFR 190 individual dose commitments for the residential receptors for the age group of infant child teenage and adult for Phase 34489-10 FINAL April 2008 6-14 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor 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 Age Group Organ Estimated Dose mrem/yr Applicable Limit mremlyr Fraction of Limit Infant Child Potential BHV Teenage Adult Effective 5.40E-O1 25 2.16E-02 Bone 1.84EOO 25 7.36E-02 Avg Lung 4.75E-O1 25 l.90E-02 Bronchi 9.63E-04 no limit given Effective 2.28E-Ol 25 9.11E-03 Bone 3OEOO 25 i2OE-02 Avg Lung 6.46E-Ol 25 2.58E-02 Bronchi 9.63E-04 no limit given Effective 2.70E-O 25 .08E-02 Bone 4.70EOO 25 1.88E-Ol Avg Lung 5.09E-O1 25 2.03E-02 Bronchi 9.63E-04 no limit given Effective l.59E-O1 25 6.36E-03 Bone 2.04EOO 25 8.17E-02 Avg Lung 3.42E-O1 25 1.37E-02 Bronchi 9.63E-04 no limit given Infant Child Historical BHV-2 Teenage Adult Effective 8.03E-02 25 3.21E-03 Bone 2.81E-Ol 25 1.12E-02 Avg Lung 8.47E-02 25 3.39E-03 Bronchi .38E-04 no limit given Effective 3.58E-02 25 l.43E-03 Bone 2.07E-O1 25 8.29E-03 Avg Lung 1.06E-O1 25 4.24E-03 Bronchi .38E-04 no limit given Effective 4.22E-02 25 .69E-03 Bone 7.23E-Ol 25 2.89E-02 Avg Lung 8.2lE-02 25 3.29E-03 Bronchi .38E-04 no limit given Effective 2.53E-02 25 1.OlE-03 Bone 3.23E-O1 25 1.29E-02 Avg Lung 5.56E-02 25 2.22E-03 Bronchi 1.3 8E-04 no limit given 34489-10 FINAL April 2008 6-15 SENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE 6.1-8 Contd PHASE 2-COMPARISON OF 40 CFR 190 ANNUAL DOSE COMMITMENTS WITH APPLICABLE RADIATION PROTECTION STANDARDS COLORADO PLATEAU ORE Age Group Organ Estimated Dose mremlyr Applicable Limit mrem/yr Fraction of Linut Infant Child Resident Teenage Adult Effective 3.15EO1 25 1.26E-02 Bone 1.08EOO 25 4.32E-02 Avg Lung 2.75E-O1 25 l.1OE-02 Bronchi 5.57E-04 no limit given Effective l.33E-O1 25 5.31E-03 Bone 759E-O1 25 3M4E-02 Avg Lung 3.76E-O1 25 1.SOE-02 Bronchi 5.57E-04 no limit given Effective 1.58E-Ol 25 6.30E-03 Bone 2.73EOO 25 1.09E-Ol Avg Lung 2.95E-Ol 25 1.18E-02 Bronchi 5.57E-04 no limit given Effective 9.28E-02 25 3.71E-03 Bone 1.19EOO 25 4.77E-02 Avg Lung l.99E-O1 25 7.94E-03 Bronchi 5.57E-04 no limit given Infant Child Community Teenage Adult Effective 3.35E-02 25 .34E-03 Bone 1.18E-O1 25 4.71E03 Avg Lung 4.50E-02 25 l.80E-03 Bronchi 4.23E-O5 no limit given Effective 1.29E-02 25 5.17E-04 Bone 7.72E-02 25 3.09E-03 Avg Lung 3.80E-02 25 l.52E-03 Bronchi 4.23E-O5 no limit given Effective .36E-02 25 5.46E-04 Bone 2.29E-O1 25 9.17E-03 Avg Lung 2.69E-02 25 1.08E-.03 Bronchi 4.23 E-05 no limit given Effective 8.60E-03 25 3.44E-04 Bone 1.09E-O1 25 4.37E-03 Avg 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 of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE 6.1-8 Contd PHASE 2-COMPARISON OF 40 CFR 190 ANNUAL DOSE COMMITMENTS WITH APPLICABLE RADIATION PROTECTION STANDARDS COLORADO PLATEAU ORE Age Group Organ Estimated Dose mrem/yr Applicable Limit mrem/yr Fraction of Limit Infant Child Teenage Adult Effective 2.21E-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 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 Bronchi .49E-O5 no limit given Effective .06E-02 25 4.23E-04 Bone 1.81E-O1 25 7.24E-03 Avg Lung 2.04E-02 25 8.18E-04 Bronchi .49E-05 no limit given Effective 6.37E-03 25 2.55E-04 Bone 8.15E-02 25 3.26E-03 Avg Lung l.39E-02 25 5.56E-04 Bronchi .49E-05 no limit given From Table 6.1-8 the 40 CFR 190 annual dose commitments are at most 18.8%dose to the bone for the teenage at BHV-1 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 R3 13-15- 1014 10 CFR 20.1101d 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 mremiyr infant at BHV-l or 5.4%of the 10 mremlyr goal In addition Table 6.1-9 presents summary of the 40 CFR 190 annual dose commitments from the meat ingestion pathway for Grazing Locations and As before in the unlikely event receptor were to eat meat from cattle grazing in areas or the total dose would remain well below regulatory limits 3448 9-10 FINAL April 2008 6-17 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE 6.1-9 PHASE 2-40 CFR 190 ANNUAL DOSE COMMITMENTS FOR MEAT INGESTION PATHWAY COLORADO PLATEAU ORE mrcmlyr Location Age Group Organb Effectiv Bon Avg Lunga Grazing Location Infant O.OOEOO O.OOEOO O.OOEOO Child 1.07E-02 5.35E-02 4.87E-02 Teenage 1.68E-02 2.78E-O1 4.26E-02 Adult 1.22E-02 l.50E-O1 3.SlE-02 Grazing Location Infant O.OOEOO O.OOEOO O.OOEOO Child 6.71E-04 3.32E-03 2.80E-03 Teenage l.03E-03 l.75E-02 2.46E-03 Adult 7.39E-04 9.20E-03 2.03E-03 The annual doses to the population estimated within 50 miles 80 lan of the 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 Organ ANNUAL POPULATION DOSE COMMITMENTS PERSON-REM PER YEAR Mill_Operations Effective Bone Avg Lung Bronchi .50E-O1 1.15EOO l.56E-Ol 8.66EOO The population dose arising from processing Colorado Plateau ore during Phase is estimated at 0.15 person-rem This can be compared to the dose from natural background sources of radiation of about 360 mremlyr as previously discussed in Phase The current population of San Juan County is about 14400 people Assuming everyone living in San Juan County receives an annual dose of about 360 mremlyr 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 Note Assumes cattle will graze at the particular Grazing location for months of the year Exclusive of radon 3448 9-10 FINAL April 2008 6-18 5ENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill 6.2 MILDO S-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 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 1a Regulatory Compliance The MILDOS-AREA calculated total annual dose commitments including radon for Phases and are provided in this section These doses are regulated by R3 13-15-3011 which requires that the dose to an individual member of the public shall not exceed 100 mremyrradon included Phase Table 6.2-1 presents summary of the individual dose commitments for the residential receptors for the age group of infant child teenage and adult for Phase 34489-10 FINAL April 2008 6-19 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE 6.2-1 PHASE 1-COMPARISON OF ANNUAL DOSE COMMITMENTS WITH APPLICABLE RADIATION PROTECTION STANDARDS ARIZONA STRIP ORE Location Age Group Organ Estimated Dose mremlyr Applicable Limit mrem/yr Fraction of Limit Nearest Potential Resident BHVA Infant Effective 3.12E00 100 3.12E02 Bone 4.86E00 Avg Lung 1.34E00 Bronchi 2.72E01 Child Effective 2.32E00 100 2.32E-02 Bone 3.48E00 Avg Lung .79E00 Bronchi 2.72E0l Teenage Effective 2.43E00 100 2.43E-02 Bone 1.23EOl Avg Lung .43E00 Bronchi 2.72E0l Adult Effective 2.14E00 100 2.14E-02 Bone 5.42E00 Avg Lung 9.94E-01 Bronchi 2.72E01 Nearest Historical Resident BHV-2 Infant Effective 6.60E-01 100 6.60E-03 Bone 7.65E-01 Avg Lung 2.58E-01 Bronchi 6.93E00 Child Effective 5.46E-01 100 5.46E-03 Bone 5.80E-01 Avg Lung 3.17E-01 Bronchi 6.93E00 Teenage Effective 5.63E-01 100 5.63E-03 Bone .92E00 Avg Lung 2.55E-01 Bronchi 6.93E00 Adult Effective 5.19E-01 100 5.19E-03 Bone 8.85E-01 Avg Lung l.85E-01 Bronchi 6.93E00 34489-10 FINAL April 2008 6-20 SENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE 6.2-1 Contd PHASE 1-COMPARISON OF ANNUAL DOSE COMMITMENTS WITH APPLICABLE RADIATION PROTECTION STANDARDS ARIZONA STRIP ORE Location Age Group Organ Estimated Dose mremlyr Applicable Limit mrem/yr Fraction of Limit Nearest Actual Resident Infant Effective 1.96E00 100 1.96E02 Bone 2.86E0O Avg Lung 7.91E-01 Bronchi 1.81E01 Child Effective 1.50E00 100 1.50E-02 Bone 2.05E00 Avg Lung 1.06E00 Bronchi 1.81 E0 Teenage Effective 1.56E00 100 1.56E-02 Bone 7.18E00 Avg Lung 8.50E-01 Bronchi l.81E01 Adult Effective .40E00 100 .40E-02 Bone 3.18E00 Avg Lung 5.96E-01 Bronchi 1.81E01 White Mesa Community Infant Effective 4.68E-01 100 4.68E-03 Bone 3.51E-01 Avg Lung l.56E-01 Bronchi 5.72E00 Child Effective 4.16E-01 100 4.16E-03 Bone 2.53E-01 Avg Lung 1.46E-01 Bronchi 5.72E00 Teenage Effective 4.1 9E-0 100 4.1 9E-03 Bone 6.90E-01 Avg Lung 1.16E-01 Bronchi 5.72E00 Adult Effective 4.04E-01 100 4.04E-03 Bone 3.51E-01 Avg Lung 9.18E-02 Bronchi 5.72E00 34489-10 FINAL April 2008 6-21 SENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE 6.2-1 Contd PHASE 1-COMPARISON OF ANNUAL DOSE COMMITMENTS WITH APPLICABLE RADIATION PROTECTION STANDARDS ARIZONA STRIP ORE Location Age Group Organ Estimated Dose mrem/yr Applicable Limit mrem/yr Fraction of Limit Blanding Infant Effective 2.18E01 100 2.18E-03 Bone 2.20E-01 Avg Lung 7.98E-02 Bronchi 2.39E00 Child Effective 1.85E-01 100 1.85E-03 Bone 1.64E-01 Avg Lung 9.22E-02 Bronchi 2.39E00 Teenage Effective 1.89E-01 100 1.89E-03 Bone 5.16E-01 Avg Lung 7.49E-02 Bronchi 2.39E00 Adult Effective 1.78E-01 100 1.78E-03 Bone 2.44E-01 Avg Lung 5.64E-02 Bronchi 2.39E00 From Table 6.2-1 the total annual effective dose commitments are at most 3.1%effective dose for infant at BHV-of the R3 13-15-3011 limit of 100 mremlyr radon included to an individual member of the public Therefore the predicted annual effective dose commitments comply with R313-15-1011a In addition Table 6.2-2 presents summary of the annual dose commitments from the meat ingestion pathway for Grazing location and As before in the unlikely event that receptor consumed beef from one of the grazing locations the total dose would remain well below regulatory limits 34489-10 FINAL April 2008 6-22 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE 6.2-2 PHASE 1-TOTAL ANNUAL DOSE COMMITMENTS FOR MEAT INGESTION PATHWAY ARIZONA STRIP ORE mremlyr Phase Location Age Gronp Organb Effectiv Bon Avg Lnnga Grazing Location Infant 0.00E00 O.OOE0O O.OOE00 Child 2.75E-02 1.37E-Ol 1.25E-01 Teenage 4.33E-02 7.1 6E-O .09E-0 Adult 3.13E-02 3.87E-O1 9.03E-02 Grazing Location Infant 0.OOE00 O.OOE00 0.00E00 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 Table 6.2-3 presents summary of the individual dose commitments for the residential receptors for the age group of infant child teenage and adult for Phase TABLE 6.2-3 PHASE 2-COMPARISON OF ANNUAL DOSE COMMITMENTS WITH APPLICABLE RADIATION PROTECTION STANDARDS ARIZONA STRIP ORE Location Age Gronp Organ Estimated Dose mremlyr Applicable Limit mrenilyr Fraction of Limit Nearest Potential Resident BHV-l Infant Effective 3.1OE00 100 3.lOE-02 Bone 4.8lE00 Avg Lung 1.31E00 Bronchi 2.70E01 Child Effective 2.30E00 100 2.30E-02 Bone 3.42E00 Avg Lung 1.74E00 Bronchi 2.70E01 Teenage Effective 2.40E00 100 2.40E-02 Bone l.21E01 Avg Lung 1.40E00 Bronchi 2.70E01 Adult Effective 2.12E00 100 2.12E-02 Bone 5.31E00 Avg Lung 9.71E-01 Bronchi 2.70EOl Note Assumes cattle will graze at the particular Grazing location for months of the year 34489-10 FINAL April 2008 6-23 5ENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE 6.2-3 Contd PHASE 2-COMPARISON OF ANNUAL DOSE COMMITMENTS WITH APPLICABLE RADIATION PROTECTION STANDARDS ARIZONA STRIP ORE Age Group Organ Estimated Dose mrem/yr Applicable Limit mremlyr Fraction of Limit Infant Child Historical BHV-2 Teenage Adult Effective 6.59E-01 100 6.59E-03 Bone 7.60E-01 Avg Lung 2.56E-01 Bronchi 6.93E00 Effective 5.45E-01 100 5.45E-03 Bone 5.75E-0l Avg Lung 3.14E-0l Bronchi 6.93E00 Effective 5.62E-01 100 5.62E-03 Bone 1.91E00 Avg Lung 2.52E-01 Bronchi 6.93E00 Effective 5.18E-01 100 5.18E-03 Bone 8.76E-01 Avg Lung l.84E-01 Bronchi 6.93E00 Infant Child Actual Teenage Adult Effective 1.95E00 100 1.95E02 Bone 2.83E00 Avg Lung 7.77E-01 Bronchi l.80E01 Effective 1.49E00 100 1.49E-02 Bone 2.02E00 Avg Lung 1.03E00 Bronchi .80E0 Effective .55E00 100 .55E-02 Bone 7.06E00 Avg Lung 8.32E-01 Bronchi 1.80E01 Effective l.39E00 100 1.39E-02 Bone 3.13E00 Avg Lung 5.84E-01 Bronchi 1.80E01 34489-10 FINAL April 2008 6-24 SENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE 6.2-3 Contd PHASE 2-COMPARISON OF ANNUAL DOSE COMMITMENTS WITH APPLICABLE RADIATION PROTECTION STANDARDS ARIZONA STRIP ORE AgeLocation Gronp Organ Estimated Dose mremlyr Applicable Limit mremlyr Fraction of Limit Infant Child Mesa Community Teenage Adult Effective 4.69E-0 100 4.69E-03 Bone 3.49E-01 Avg Lung l.55E-0l Bronchi 5.75E00 Effective 4.17E-01 100 4.17E-03 Bone 2.52E-01 Avg Lung 1.45E-01 Bronchi 5.75E00 Effective 4.20E-01 100 4.20E-03 Bone 6.85E-01 Avg Lung 1.15E-01 Bronchi 5.75E00 Effective 4.05E-01 100 4.05E-03 Bone 3.48E-01 Avg Lung 9.14E-02 Bronchi 5.75E00 Infant Child Teenage Adult Effective 2.19E-01 100 2.19E-03 Bone 2.20E-01 Avg Lung 7.98E-02 Bronchi 2.40E00 Effective 1.86E-Ol 100 l.86E-03 Bone 1.64E-01 Avg Lung 9.22E-02 Bronchi 2.40E00 Effective .90E-0 100 .90E-03 Bone 5.15E-Ol Avg Lung 7.49E-02 Bronchi 2.40E00 Effective 1.79E-01 100 1.79E-03 Bone 2.44E-01 Avg Lung 5.65E-02 Bronchi 2.40E00 34489-10 FINAL April 2008 6-25 SENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill Location Age Group Organb Effectiv Bonea Avg Lunga Grazing Location Infant O.OOEOO O.OOEOO O.OOEOO Child 2.73E-02 .36E-O .24E-O Teenage 4.29E-02 7.1OE-Ol l.08E-O1 Adult 3.1OE-02 3.83E-O1 8.94E-02 Grazing Location Infant O.OOEOO O.OOEOO O.OOE-I-OO Child 1.71E-03 8.50E-03 7.18E-03 Teenage 2.65E-03 4.48E-02 6.28E-03 Adult .89E-03 2.35E-02 5.1 8E-03 Note Assumes cattle will graze at the particular Grazing location for months of the 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 mremlyr 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 R3 13-15-1014 10 CFR 20.1101d The licensee must demonstrate as an ALARA goal 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 mremlyr absent of the radon dose Phase Table 6.2-5 presents summary of the 40 CFR 190 individual dose commitments for residential receptors for the age group of infant child teenage and adult for Phase From Table 6.2-3 the total annual effective dose commitments are at most 3.1%effective dose for infant at BHV-1 of the R313-15-3011a limit of 100 mremlyr radon included to an individual member of the public Therefore the predicted annual effective dose commitments comply with R313-15-1011a In addition Table 6.2-4 presents summary of the annual dose commitments from the meat ingestion pathway for Grazing location and As before in the unlikely event that 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 mrem/yr 34489-10--FINAL April 2008 6-26 5ENE5 consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE 6.2-5 PHASE 1-COMPARISON OF 40 CFR 190 ANNUAL DOSE COMMITMENTS WITH APPLICABLE RADIATION PROTECTION STANDARDS ARIZONA STRIP ORE AgeLocation Group Organ Estimated Dose mrem/yr Applicable Limit mrem/yr Fraction of Linut Infant Child Potential BHV-Teenage Adult Effective l.39EOO 25 5.55E-02 Bone 4.76EOO 25 1.90E-O1 Avg Lung 1.24EOO 25 4.95E-02 Bronchi 2.48E-03 no limit given Effective 5.92E-Ol 25 2.37E-02 Bone 3.37EOO 25 1.35E-Ol Avg Lung .69EOO 25 6.74E-02 Bronchi 2.48E-03 no limit given Effective 7.03E-O 25 2.81 E-02 Bone 1.22EO1 25 4.88E-Ol Avg Lung 1.33EOO 25 5.31E-02 Bronchi 2.48E-03 no limit given Effective 14E-O1 25 .66E-02 Bone 5.32EOO 25 2.13E-O1 Avg Lung 8.93E-O1 25 3.57E-02 Bronchi 2.48E-03 no limit given Infant Effective 2.06E-Ol 25 8.24E-03 Bone 7.20E-O1 25 2.88E-02 Avg Lung 2.18E-O1 25 8.73E-03 Bronchi 3.54E-04 no limit given Child Effective 9.19E-02 25 3.68E-03 Bone 5.32E-Ol 25 2.l3E-02 Avg Lung 2.73E-O1 25 l.09E-02 Historical Bronchi 3.54E-04 no limit given BHV2 Teenage Effective .09E-O 25 4.34E-03 Bone l.86EOO 25 7.44E-02 Avg Lung 2.11E-O1 25 8.44E-03 Bronchi 3.54E-04 no limit given Adult Effective 6.49E-02 25 2.60E03 Bone 8.30E-O1 25 3.32E-02 Avg Lung l.43E-Ol 25 5.73E-03 Bronchi 3.54E-04 no limit given 34489-10 FINAL April 2008 6-27 SENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE 6.2-5 Contd PHASE 1-COMPARISON OF 40 CFR 190 ANNUAL DOSE COMMITMENTS WITH APPLICABLE RADIATION PROTECTION STANDARDS ARIZONA STRIP ORE Age Gronp Organ Estimated Dose mreni/yr Applicable Limit mrem/yr Fraction of Limit Infant Child Actual Teenage Adult Effective 8.11 E-O 25 .24E-02 Bone 2.79EOO 25 1.11E-O1 Avg Lung 7.16E-O1 25 2.86E-02 Bronchi .44E-03 no limit given Effective 3.44E-O1 25 1.38E-02 Bone 1.97EOO 25 7.88E-02 Avg Lung 9.78E-O1 25 3.91E-02 Bronchi .44E-03 no limit given Effective 4.09E-O1 25 .64E-02 Bone 7.09EOO 25 2.83E-O1 Avg Lung 7.71E-O1 25 3.08E-02 Bronchi .44E-03 no limit given Effective 241E-O1 25 964E-03 Bone 3.09EOO 25 1.24E-O1 Avg Lung 5.17E-O1 25 2.07E-02 Bronchi .44E-03 no limit given Infant Child Mesa Teenage Adult Effective 8.58E-02 25 3.43E-03 Bone 3.02E-O1 25 l.21E-02 Avg Lung 1.l6E-O1 25 4.64E-03 Bronchi .08E-04 no limit given Effective 3.33E-02 25 1.33E-03 Bone l.99E-Ol 25 7.95E-03 Avg Lung 9.80E-02 25 3.92E-03 Bronchi .08E-04 no limit given Effective 3.51 E-02 25 .41E-03 Bone 5.90E-O1 25 2.36E-02 Avg Lung 6.92E-02 25 2.77E-03 Bronchi .08E-04 no limit given Effective 2.21E-02 25 8.85E-04 Bone 2.82E-Ol 25 1.13E-02 Avg Lung 4.87E-02 25 1.95E-03 Bronchi .08E-04 no limit given 34489-10 FINAL April 2008 6-28 SENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE 6.2-5 Contd PHASE 1-COMPARISON OF 40 CFR 190 ANNUAL DOSE COMMITMENTS WITH APPLICABLE RADIATION PROTECTION STANDARDS ARIZONA STRIP ORE Location Age Group Organ Estimated Dose mremlyr Applicable Limit mremlyr Fraction of Limit Blanding Infant Effective 5.64E-02 25 2.26E-03 Bone l.96E-Ol 25 7.83E-03 Avg Lung 6.08E-02 25 2.43E-03 Bronchi 8.89E-05 no limit given Child Effective 2.35E-02 25 9.41E-04 Bone 1.37E-O1 25 5.48E-03 Avg Lung 6.86E-02 25 2.74E-03 Bronchi 8.89E-OS no limit given Teenage Effective 2.70E-02 25 1.08E-03 Bone 4.62E-Ol 25 l.85E-02 Avg Lung 5.20E-02 25 2.08E-03 Bronchi 8.89E-05 no limit given Adult Effective .63E-02 25 6.SOE-04 Bone 2.08E-O1 25 8.32E-03 Avg Lung 3.55E-02 25 1.42E-03 Bronchi 8.89E-05 no limit given From Table 6.5-2 the 40 CFR 190 annual dose commitments are at most 48.8%dose to the bone for the teenage at BHV-1 of the 40 CFR 190 dose criterion of 25 mremlyr In addition the 40 CFR 190 annual effective dose commitments demonstrate compliance with the R3 13-15- 1014 10 CFR 20.1101d 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 1.39 mremlyr infant at BHV-1 or 13.9%of the 10 mrem/yr goal In addition Table 6.2-6 presents summary of the 40 CFR 190 annual dose commitments from the meat ingestion pathway for Grazing location and As before in the unlikely event that someone was to consume beef from grazing area or the total dose would be small and well below regulatory limits 34489-10 FINAL April 2008 6-29 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE 6.2-6 PHASE 1-40 CFR 190 ANNUAL DOSE COMMITMENTS FOR MEAT INGESTION PATHWAY ARIZONA STRIP ORE mremlyr Location Age Group Organ Effectiv Born Avg Lunga Grazing Location Infant O.OOEOO O.OOEOO O.OOEOO Child 2.75E-02 1.37E-O1 1.25E-O1 Teenage 4.33E-02 16E-O1 .09E-Ol Adult 3.13E-02 3.87E-O1 9.03E-02 Grazing Location Infant O.OOEOO O.OOEOO O.OOEOO Child l.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 5.7lE-03 The annual doses to the population estimated within 50 miles 80 km of the site are provided in Table 6.2-7 TABLE 6.2-7 PHASE 1-ANNUAL POPULATION DOSE COMMITMENTS WITHIN 50 MILES 80 km OF THE MILL FOR ARIZONA STRIP ORE Organ ANNUAL POPULATION DOSE COMMITMENTS PERSON-REM PER YEAR Mill_Operations Effective Bone Avg Lung Bronchi 3.08E-O1 2.48EOO 3.28E-O1 .64EO The population dose arising from processing Arizona Strip ore during Phase is estimated at 0.31 person-rem This can be compared to the dose from natural background sources of radiation of about 360 mremlyr as previously discussed The current population of San Juan County is about 14400 people Assuming everyone living in San Juan County receives an annual dose of about 360 mrent/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 Note Assumes cattle will graze at the particular Grazing location for months of the year Exclusive of radon 34489-10 FINAL April 2008 6-30 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill Phase Table 6.2-8 presents summary of the 40 CFR 190 individual dose commitments for residential receptors for the age group of infant child teenage and adult for Phase TABLE 6.2-8 PHASE 2-COMPARISON OF 40 CFR 190 ANNUAL DOSE COMMITMENTS WITH APPLICABLE RADIATION PROTECTION STANDARDS ARIZONA STRIP ORE Age Group Organ Estimated Dose mremlyr Applicable Limit mremlyr Fraction of Limit Infant Effective 1.38EOO 25 5.50E-02 Bone 4.71EOO 25 1.88E-Ol Avg Lung l.21EOO 25 4.84E-02 Bronchi 2.45E-03 no limit given Child Effective 5.81E-Ol 25 2.32E-02 Bone 3.31EOO 25 1.32E-Ol Avg Lung 1.64EOO 25 6.58E-02 Potential Bronchi 2.45E-03 no limit given BHV-1 Teenage Effective 6.89E-Ol 25 2.76EM2 Bone 1.20EOl 25 4.79E-Ol Avg Lung 1.29EOO 25 5.18E-02 Bronchi 2.45E-03 no limit given Adult Effective 4.05E-O 25 .62E-02 Bone 5.21EOO 25 2.08E-Ol Avg Lung 8.71E-Ol 25 3.48E-02 Bronchi 2.45E-03 no limit given 34489-10 FINAL April 2008 6-3 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE 6.2-8 Contd PHASE 2-COMPARISON OF 40 CFR 190 ANNUAL DOSE COMMITMENTS WITH APPLICABLE RADIATION PROTECTION STANDARDS ARIZONA STRIP ORE Age Group Organ Estimated Dose mrem/yr Applicable Limit mremlyr Fraction of Limit Infant Effective 2.05E-O1 25 8.20E-03 Bone 7.16E-O1 25 2.86E-02 Avg Lung 2.16E-Ol 25 8.64E-03 Bronchi 3.53E-04 no limit given Child Effective 9.1 1E-02 25 3.64E-03 Bone 5.27E-O1 25 2.11E-02 Avg Lung 2.70E-O1 25 1.08E-02 Historical Bronchi 3.53E-04 no limit given BHV-2 Teenage Effective .07E-O1 25 4.30E-03 Bone 1.84EOO 25 7.38E-02 Avg Lung 2.09E-O1 25 8.35E-03 Bronchi 3.53E-04 no limit given Adult Effective 6.42E-02 25 237E-03 Bone 8.22E-O1 25 3.29E-02 Avg Lung l.42E-O1 25 5.66E-03 Bronchi 3.53E-04 no limit given Infant Child Actual Teenage Adult Effective 8.04E-O1 25 3.22E-02 Bone 2.76EOO 25 1.1OE-O1 Avg Lung 7.02E-Ol 25 2.81E-02 Bronchi .42E-03 not limited Effective 3.39E-O1 25 l.35E-02 Bone .94EOO 25 7.74E-02 Avg Lung 9.57E-O1 25 3.83E-02 Bronchi .42E-03 not limited Effective 4.02E-O1 25 .61E-02 Bone 6.97EOO 25 2.79E-Ol Avg Lung 7.54E-Ol 25 3.02E-02 Bronchi .42E-03 not limited Effective 2.36E-Ol 25 9.46E-03 Bone 3.03EOO 25 l.21E-O1 Avg Lung 5.06E-O1 25 2.02E-02 Bronchi .42E-03 not limited 34489-10 FtNAL April 2008 6-32 SENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE 6.2-8 ContcI PHASE 2-COMPARISON OF 40 CFR 190 ANNUAL DOSE COMMITMENTS WITH APPLICABLE RADIATION PROTECTION STANDARDS ARIZONA STRIP ORE AgeLocation Group Organ Estimated Dose mrem/yr Applicable Limit mremlyr Fraction of Limit Infant Child Mesa Community Teenage Adult Effective 8.53E-02 25 3.41E-03 Bone 3.OOE-O1 25 1.20E-02 Avg Lung 1.15E-O1 25 4.59E-03 Bronchi .08E-04 not limited Effective 3.30E-02 25 1.32E-03 Bone 1.97E-O1 25 7.87E-03 Avg Lung 9.68E-02 25 3.87E-03 Bronchi .08E-04 not limited Effective 3.48E-02 25 .39E-03 Bone 5.85E-O1 25 2.34E-02 Avg Lung 6.83E-02 25 2.73E-03 Bronchi .08E-04 not limited Effective 2.19E-02 25 8.75E-04 Bone 2.79E-O1 25 1.12E-02 Avg Lung 4.8lE-02 25 1.92E-03 Bronchi .08E-04 not limited Infant Child Teenage Adult Effective 5.64E-02 25 2.26E-03 Bone 1.96E-O1 25 7.82E-03 Avg Lung 6.07E-02 25 2.43E-03 Bronchi 8.88E-05 not limited Effective 2.35E-02 25 9.40E-04 Bone 1.37E-O1 25 5.47E-03 Avg Lung 6.84E-02 25 2.74E-03 Bronchi 8.88E-05 not limited Effective 2.70E-02 25 .08E-03 Bone 4.61E-O1 25 l.85E-02 Avg Lung 5.19E-02 25 2.08E-03 Bronchi 8.88E-05 not limited Effective .62E-02 25 6.49E-04 Bone 2.08E-O1 25 8.31E-03 Avg Lung 3.55E-02 25 1.42E-03 Bronchi 8.88E-05 not limited 34489-10 FINAL April 2008 6-33 SENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill 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-1 of the 40 CFR 190 dose criterion of 25 mremlyr In addition the 40 CFR 190 annual effective dose commitments demonstrate compliance with the R3 13-15- 1014 10 CFR 20.1101d ALARA goal of 10 mremyrto the individual member of the public likely to receive the highest total effective dose equivalent The maximum total effective dose equivalent was 1.38 mremlyr infant at BHV-1 or 13.8%of the 10 mremyrgoal In addition Table 6.2-9 presents summary of the 40 CFR 190 annual dose commitments from the meat ingestion pathway for Grazing location and As before in the unlikely event that someone was to consume beef from grazing area or 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 mrem/yr Location Age Group Organ Effectiv Bon Avg Lunga Grazing Location Infant O.OOEOO O.OOEOO O.OOEOO Child 2.73E-02 .36E-O .24E-O Teenage 4.29E-02 7.1OE-Ol l.08E-Ol Adult 3.1 OE-02 3.83E-O 8.94E-02 Grazing Location Infant O.OOEOO O.OOEOO O.OOEOO Child l.71E-03 8.48E-03 7.14E-03 Teenage 2.63E-03 4.46E-02 6.25E-03 Adult .88E-03 2.35E-02 5.1 7E-03 The annual doses to the population estimated within 50 miles 80 1cm 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 Organ ANNUAL POPULATION DOSE COMMITMENTS PERSON-REM PER YEAR Mill Operations Effective Bone Avg Lung Bronchi 3.15E-O1 2.55EOO 3.34E-O1 .65EO Note Assumes cattle will graze at the particular Grazing location for months of the year Exclusive of radon 34489-10 FINAL April 2008 6-34 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill The population dose arising from processing Arizona Strip ore during Phase 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 mremlyr as previously discussed The current population of San Juan County is about 14400 people Assuming everyone living in San Juan County receives an annual dose of about 360 mremlyr 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 34489-10 FINAL April 2008 6-35 SENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill 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 DUSA 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 license amendment application for the construction and operation of that cell The NRC-approved MILDOS-AREA was used to estimate the dose commitments received by individuals and the general population within 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 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 7-1 provides summary of the source terms included in Phases and TABLE 7-1 SOURCE TERMS INCLUDED IN PHASES AND Source Term Phase Phase Mill area included included Ore Pads included included Tailings Cell with Interim Soil Cover included included Tailings Cell active interim soil cover Tailings Cell 4A active active Tailings Cell 4B excluded active The wind erosion and radon release rates from the tailings cells active and with interim soil cover were modelled by using 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 61.252b Subpart since it is not possible to predict the distribution of uncovered tailings between the active cells at any given time As 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 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 of each cell consistent with NESHAPs The tailings cells and with interim soil cover were assumed to be the entire areas of each cell however only radon is released at rate of 10 pCi/m2s after the application of the soil cover 34489-10 FINAL April 2008 7-1 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill The calculated total annual effective dose commitments including radon calculated using MILD OS-AREA were compared to the Utah Administrative Code R3 13-15-3011 requirement that the dose to individual members of the public shall not exceed 100 mremlyr radon included For processing of Colorado Plateau ore the maximum total annual effective dose commitments was calculated to be maximum of 1.4 mremlyr 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%of the R3 13-15-3011 limit of 100 mremlyr radon included to an individual member of the public for Phases and For processing of Arizona Strip ore the total annual effective dose commitments were calculated to be maximum of 3.1 mremlyr for an infant at the nearest potential resident BHV-1 Tables 6.2-1 and 6.2-3 i.e effective dose and is about 3.1%of the 100 mremyr limit radon included to an individual member of the public for Phases and Overall using conservative assumptions the predicted annual effective dose commitments for Phases and 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 mremlyr 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 R313-15-1014 10 CFR 20.1101d 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 mremyr absent of the radon dose For processing of Colorado Plateau ore the 40 CFR 190 annual dose commitments were calculated to be maximum of 4.8 mremlyr for teenager at the nearest potential resident BHV-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 mremyr for Phases and Further the 40 CFR 190 annual effective dose commitments demonstrate compliance with the R3 13-15-1014 10 CFR 20.1101d 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 and was 0.545 mrem/yr for an infant at BHV-1 For Arizona Strip ore the 40 CFR 190 annual dose commitments were at most 12 mremlyr for teenage at the nearest potential resident BHV-1 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 mremlyr for Phases and Further the 40 CFR 190 annual effective dose commitments demonstrate compliance with the R3 13-15-1014 10 CFR 20.1101d 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 and was 1.39 mremlyr for an infant at BHV-1 Overall using conservative assumptions ore processing in Phases and comply with the requirements of 40 CFR 190 and the ALARA goal set out in R313 -15-1014 34489-10 FINAL April 2008 7-2 5ENE5 Consultants Limited Proposed Development ofNew Tailings Cell 4Bfor White Mesa Uranium Mill 8.0 REFERENCES Argonne National Laboratory ANL 1998a MILDOS-AREA Version 2.20/3 Developed at the Environmental Assessment Division Argonne National Laboratory ANL 998b MILDOS-AREA User Guide Draft Environmental Assessment Division Code of Federal Regulations CFR Title 10 Part 20 Standards for 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 199 lb 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 December United States Environmental Protection Agency EPA 2002 Code of Federal CFR Regulations Title 40 Part 190 Environmental Radiation Protection for Nuclear Power Operations February Google 2005 Google Earth Pro 3.0.0 762 November International Commission on Radiological Protection ICRP 1959 Report of ICRP Committee lIon Permissible Dose for Internal Radiation Health Physics 31-380 1960 International Commission on Radiological Protection ICRP 1966 Deposition and retention models for internal dosimetry of the human respiratory tract Health Physics 12 173-207 34489-10 FINAL April 2008 8-1 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill International Commission on Radiological Protection ICRP 1971 Recommendations of the International Commission on Radiological Protection ICRP Publication OA Pergamon Press New York International Commission on Radiological Protection ICRP 1972 The Metabolism of Compounds of Plutonium and Other Actinides ICRP Publication 19 Pergamon Press International Commission on Radiological Protection ICRP 1979 Limits for Intakes of Radionuclides by Workers adopted from July 1978 ICRP Publication 30 Landau 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 September United States Nuclear Regulatory Commission NRC 1987 Methods for Estimating Radioactive and Toxic Airborne Source Terms for 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 Mines USA Corp February Strenge D.L and Bander T.J 1981 MILDOS-Computer Program for Calculating Environmental Radiation Doses from Uranium Recovery Operations NUREG/CR-201 Prepared for U.S Nuclear Regulatory Commission Turk 2007a Email to Ho RE Receptor GPS Received February 14-15 Turk 2007b Email to Chambers FW Additional Weather Information Received Feb Yu 1992 Calculation of Radiation Dose from Uranium Recovery Operations for Large Area-Sources Argonne National Laboratory 34489-10 FINAL April 2008 8-2 SENES Consultants Limited Proposed Development ofNew Tailings Cell 4Bfor White Mesa Uranium Mill APPENDIX HISTORY OF MILDOS 34489-10 FINAL-April 2008 SENES Consultants Limited Proposed Development ofNew Tailings Cell 4Bfor White Mesa Uranium Mill APPENDIX HISTORY OF MILDOS The MILDOS computer code was developed from the version IV for Argonne National Laboratorys ANL Uranium Dispersion and Dosimetry UDAD computer program 198 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 Airborne 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 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 reduction in the number of sources from 20 to 10 in MILDOS-AREA due to the fact that large area can be considered as single source rather than two or more point sources The internal 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 R3 13-15 The calculations of ingestion DCFs were based on ICRP Publication and 1OAs 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 function of particle 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 part of the input options The annual average air concentrations were computed to the maximum permissible concentrations MPCs in 10 CFR 20 The MPCs in 10 CFR 20 incorporated by reference in R3 13-15 were revised in 1994 to incorporate the updated dosimetry to the 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 revised calculation 34489-10--FINAL April 2008 A-i 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill 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 graphical user interface GUI which provides an interface for the user to input each parameter needed for the calculations in the Windows operating system The GUI 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 external exposure from ground concentrations external exposure from cloud immersion ingestion of vegetables ingestion of meat and ingestion of milk 34489-10 FINAL April 2008 A-2 5ENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill APPENDIX EMISSION CALCULATIONS 34489-10 FINAL April 2008 SENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill APPENDIX EMISSION CALCULATIONS Supplemental Information which describes the model and assumptions used to calculate the source emissions for the sources described in Section 4.0 are provided below B.1 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 equation from NRC Regulatory Guide 3.59 NRC 1987 The equation of for the dusting rate is calculated as follows 3.156x10 xR5F5 B.l where annual dust loss per unit area in g/m2yr Fs annual average frequency of occurrence of wind speed group dimensionless obtained from the joint relative frequency distribution for the mill provided by DUSA Turk 2007b R5 resuspension rate for the tailings pond at the average wind speed for wind group for particles 20 jim in diameter in glm2s 3.156 o7 number of seconds per year and 0.5 fraction of the total dust lost constituted by particle 20 jim in diameter TABLE B.1 PARAMETER VALUES FOR CALCULATION OF ANNUAL DUSTING RATE FOR EXPOSEDTAILINGS Wind Speed kts Average Wind Speed Resuspension Rate g/Za Frequency of Occurrence F5b R5 Oto3 1.5 0.165 0.OOE00 to 5.5 0.427 0.00E00 to 10 10.0 3.92E-07 0.276 1.08E-07 11 to 16 15.5 9.68E-06 0.106 1.03E-06 17to21 21.5 5.71E-05 0.021 1.20E-06 21 28.0 2.08E-04 0.005 1.04E-06 3.37E-06 Notes Resuspension rate of ifinction of wind speed is computed by the MILDOS code Wind speed frequency obtained from joint frequency distribution data provided by DUSA Turk 2007b 34489-10 FINAL April 2008 B-i 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill Using equation and the parameters in Table B-the annual dust loss from the tailings cells is approximately 213 g/m2yr As mentioned in Section 4.2.1 the annual dust lost for ore pads is 10%of that of the tailings cells since the particulates on the ore pad are coarse material to inch because the ore has not yet been ground therefore the annual dust loss from the ore pad is 21.29 g/m2yr 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-2l0 and radon emission rates from the grizzly grinding ore pads vanadium stack exclusively for processing Colorado Plateau ore yellowcake stacks north 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 ff1.1 Wet Grinding Radioactive Particulate Emission Rates Colorado Plateau Ore Arizoua Strip Ore Process Rate tpy 730000 730000 Contaminant Concentration Ci/g U-238 700 1783 Process Emission Factor lbs/tona 0.16 0.16 Activity Enrichment Ratio 2.5 2.5 Control Factor %b 99.90 99.90 Notes For moisture 8%NRC 1987 Particulate emission control from the wet grinding operations was assumed to be 99.9%EnecoTech 1991 and 1999b The U-238 Emission Rate is calculated as follows Process Rate tons/yrProcess Emission Factor lbs/ton 453.6 g/lbContaminant Concentration pCi/gActivity Enrichment Ratio 1-Control Factorl 012 Ci/pCi B.2- Using equation B.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-2 10 are assumed to be in secular equilibrium therefore the decay daughters are also emitted at rate of 9.27E-05 Ci/yr Similarly the U-238 Emission Rate from the wet grinding operations 34489-10 FINAL April 2008 B-2 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill of Arizona Strip ore is approximately 2.36E-04 Ci/yr and the decay daughters Th-230 Ra-226 and Pb-210 are also emitted at rate of 2.36E-04 Ci/yr Radon Emission Rates Colorado Plateau ore Arizona Strip ore Process Rate tpy 730000 730000 Contaminant Concentration pCilgRa-226 700 1783 Activity Factor%a 20 20 Note It was assumed that only 20%of the 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 Process Rate tons/yr2000 lbslton453.6 g/lb Contaminant Concentration pCi/g Ra226 1012 Ci/pCiActivity Factor B.2-2 Using equation B.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 B.2.2 Ore Dump to Grizzly Radioactive Particulate Emission Rates Colorado Plateau Ore Arizona Strip Ore Process Rate tpy 730000 730000 Contaminant Concentration pCilg U-238 700 1783 Process Emission Factor lbs/tona 0.16 0.16 Activity Enrichment Ratio 2.5 2.5 Control Factor 99.90 99.90 Notes For moisture 8%NRC 1987 Grizzly Dump is enclosed on three sides Trucks dump inside enclosure under negative pressure The ID fans are ducted through baghouse Ore moisture content is 10 EnecoTech 199la and l999b 34489-10 FINAL April 2008 B-3 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill The U-238 Emission Rate is calculated as follows Process Rate tons/yrProcess Emission Factor lbs/ton453.6 g/lb Contaminant Concentration pCi/gActivity Enrichment Ratiol -Control Factor 1042 Ci/pCi B.2-3 Using equation B.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-2 10 are assumed to be in secular equilibrium therefore the decay daughters are also emitted at 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-2l0 are also emitted at rate of 2.36E-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 Ore Arizona Strip Ore Process Rate tpy U305 1716 4371 Contaminant Concentration Ci/g of U-238 3.33E-07 3.33E-07 Process Emission Factor U-238/g U308 0.848 0.848 Emission Rate lbs/tona 0.092 0.092 Note Based stack tests that showed an emission rate of 0.06 lbs/hr U305 per 1300 lbs/hr process rate which translates to 0.092 lb/ton including controls EnecoTech 1991 and 999b The U-238 Emission Rate for one yellowcake stack is calculated as follows Rate tons/yr U308Emission Rate lbs/tonProcess Emission Factor 453.6 g/lbContaminant Concentration Ci/g/2 B.2-4 34489-10 FINAL April 2008 B-4 5ENE5 Consultants Limited Proposed Development of New 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 1.01 E-02 Ci/yr 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 1.31E-05 and 7.88E-05 Ci/yr respectively from each yellowcake stack north and south yellowcake stacks Similarly the U-23 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.O1E-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%U305 NRC 1980 Therefore the emission rates of U-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 Radioactive Particulate Emission Rate Ci/yr Total from Yellowcake Stacks Vanadium Stacka U-238 2.02E-02 1.O1E-06 Th-230 4.45E-05 2.22E-09 Ra-226 2.63E-05 1.31E-09 Pb-210 l.58E-04 7.88E-09 Note Total from yellowcake stacks north and south yellowcake stacksO.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 of New Tailings Cell 4Bfor White Mesa Uranium Mill B.25 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 300000 tons of ore are temporarily stockpiled with height of 30 ft 9.1 and bulk density of ore of 120 lbs/ft3 1.47 tons/yd3 Using these assumptions the area of the ore pad is approximately 17000 m2 Radioactive Particulate Emission Rates Source Description Truck Unloading Colorado Plateau Ore Arizoua Strip Ore Process Rate tpy 730000 730000 Contaminant Concentration pCi/g U-238 700 1783 Process Emission Factor lbs/yd3a 0.04 0.04 Activity Emission Ratio 2.5 2.5 Control Factor None None Bulk Density of Ore tons/yd3 1.47 1.47 Note Process emission factor for Truck end dump NRC 1987 The U-238 Emission Rate is calculated as follows Process Rate tons/yr1 yd3/1 .47 tons Process Emission Factor lbs/yd3453 .6 WlbContaminant Concentration pCi/g Activity Enrichment Ratio 10.12 Ci/pCi B.2-5 Using equation B.2-5 the U-238 Emission Rate from truck unloading Colorado Plateau ore is approximately .58E-02 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 rate of 1.58E-02 Ci/yr Similarly the U-238 Emission Rate from truck 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 rate of 4.02E-02 Ci/yr 34489-10 FINAL April 2008 B-6 5ENE5 Consultants Limited Proposed Development ofNew Tailings Cell 4Bfor White Mesa Uranium Mill Source Description Wind Erosion Colorado Plateau Ore Arizona Strip Ore Area m2f 17000 17000 Contaminant Concentration pCi/g U-238 700 1783 Process Emission Factor glm2yrt 21.29 21.29 Activity Enrichment Ratio 2.5 2.5 Control Factor %C 50 50 Notes Calculated assuming stockpile of 300000 tons of ore with height of 30 ft and bulk ore density of 1.47 tons/yd3 The process emission factor for the ore pad was derived in Section The control factor of 50%is based on the assumption that an active watering program will be in place during operations EnecoTech 1991 and 999b The U-238 Emission Rate is calculated as follows Process Emission Factor g/m2yrArea m2Contaminant Concentration pCilg Activity Enrichment RatiolControl FactorlO2 Ci/pCi B.2-6 Using equation B.2-6 the U-238 Emission Rate from trucks unloading Colorado Plateau ore is approximately 3.17E-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 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 rate of 8.07E-04 Ci/yr The total radioactive particulate emission rates from the ore pad are obtained by adding the results of truck unloading and wind erosion and are as follows Radioactive Particulate Emission Rate Ci/yr Colorado Plateau Ore Arizona Strip Ore U-238 1.61E-02 4.1OE-02 Th-230 1.61E-02 4.1OE-02 Ra-226 1.61E-02 4.1OE-02 Pb-210 1.61E-02 4.1OE-02 34489-10 FINAL April 2008 B-7 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill Radon Emission Rates Colorado Plateau ore Arizona Strip ore Aream2 17000 17000 Contaminant Concentration pCi/g Ra-226 700 1783 Specific Radon Flux Factor pCi Rn-222/m2s/pCilg Ra- 226 Radon Release Specific Radon Flux Factor pCi Rn-222Im2s/pCi/g Ra226Contaminant Concentration pCi/g Ra226Area m23.1 56x o7 s/yr 1012 Ci/pCi B.2-7 Using equation B.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 B.2-6 Tailings Cells Factors used to Calculate Radioactive Particulate Emission Rates Colorado Plateau Ore Arizona Strip Ore Active Active Cell Cell 4A/4B Cell Cell 4A/4B Area acres 10 10 10 10 Contaminant Concentration pCiIg U- 42 42 107 107 Contaminant Concentration of all other isotopes pCilg 700 700 1783 1783 Process Emission Factor Ew glm2yr 213 213 213 213 Activity Enrichment Ratio 2.5 2.5 2.5 2.5 Control Factor %C 70 70 70 70 Notes Assumes 94%recovery The process emission factor for the tailings cells was derived in Section 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 of the tailings by wind EnecoTech 1991 and 199 lb 34489-10 FINAL April 2008 B-8 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill The Emission Rate for U-23 and its decay daughters were calculated as follows Process Emission Factor g/m2yrArea acres4047 m2/acre Contaminant Concentration pCi/g Activity Enrichment Ratio 1-Control Factor 1012 Ci/pCi B.2-8 Using equation B.2-8 the U-238 Emission Rate from the active tailings cells 4A and 4B from the processing of Colorado Plateau ore is approximately 2.71E-04 Ci/yr The decay daughters Th-230 Ra-226 and Pb-210 are emitted at rate of 4.52E-03 Ci/yr Similarly the U-238 Emission Rate from the active tailings cells 4A and 4B from the processing of Arizona Strip ore is approximately 6.91E-04 Ci/yr The decay daughters Th-230 Ra-226 and Pb-2 10 are emitted at rate of 1.1 5E-02 Ci/yr There is no dust released from tailings cells and with interim covers Factors Used to Calculate Radon Emission Rates Colorado Plateau Arizona Strip Ore Interim Soil Cover Active Cell Cell Cell Cell 4A4B Area acres 66.8 70 70 40 Contaminant Concentration pCilm2s 10 10 20 20 Radon Release Contaminant Concentration pCi/m2sArea acres4047 m2/acre3.1 56x o7 s/yr 1012 Ci/pCi B.2-9 Using equation B.2-9 the radon release from the active tailings cells 4A and 4B are approximately 179 and 102 Ci/yr respectively The radon release for tailings cells and with interim cover are approximately 85.3 and 89.4 Ci/yr respectively 34489-10 FINAL April 2008 B-9 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill APPENDIX MILDOS-AREA RESULTS 34489-10 FINAL April 2008 SENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill APPENDIX 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 and are provided in Sections and C.2 for Colorado Plateau ore and Arizona Strip ore respectively C.1 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 of Colorado Plateau ore are provided in Sections 1.1 and 1.2 respectively C.1.1 R3 13-15-301 1a Regulatory Compliance TABLE C.1-1 ANNUAL DOSE COMMITMENTS COLORADO PLATEAU ORE Location Age Group Organ Es timated Dos mrem/yr Mill Area inclnding Interim oil Cover Active Tailings Tailings Taffings Taffings Tailings ore pads Cell Cell Cell Cell 4A Cell 4B Nearest Potential Resident BHVA ant Effective l.11EOO 6.03E-02 5.84E-02 1.30E-O1 6.88E-02 5.55E-02 Bone l.81EOO 2.57E-03 2.70E-03 6.09E-02 4.94E-02 3.74E-02 Avg Lung 4.66E-O1 2.45E-03 2.55E-03 3.46E-02 2.77E-02 2.14E-02 Bronchi 9.22EOO 9.67E-O1 9.34E-Ol 1.87EOO 9.14E-O1 7.44E-O1 Child Effective 7.96E-O1 6.03E-02 5.84E-02 l.29E-O1 6.77E-02 5.46E-02 Bone 1.24EOO 2.65E-03 2.79E-03 7.48E-02 6.06E-02 4.54E-02 Avg Lung 6.20E-O1 2.56E-03 2.69E-03 4.86E-02 3.88E-02 2.92E-02 Bronchi 9.22EOO 9.67E-Ol 9.34E-O1 l.87EOO 9.14E-O1 7.44E-Ol eenage Effective 8.34E-Ol 6.04E-02 5.85E-02 1.32E-O1 7.OSE-02 5.66E-02 Bone 4.40EOO 3.28E-03 3.53E-03 2.42E-O1 1.98E-Ol l.46E-O1 Avg Lung 4.94E-O1 2.54E-03 2.66E-03 3.99E-02 3.15E-02 2.38E-02 Bronchi 9.22EOO 9.67E-O1 9.34E-Ol 1.87EOO 9.14E-O1 7.44E-O1 Ad Effective 7.30E-O1 6.03E-02 5.84E-02 l.27E-O1 6.59E-02 5.32E-02 Bone 1.9lEOO 2.85E-03 3.03E-03 l.20E-O1 9.80E-02 7.29E-02 Avg Lung 3.43E-Ol 2.SOE-03 2.61E-03 2.88E-02 2.25E-02 1.70E-02 Bronchi 9.22EOO 9.67E-O1 9.34E-O1 l.87EOO 9.14E-Ol 7.44E-Ol 34489-10--FINAL April 2008 C-l 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE C.1-1 Contd ANNUAL DOSE COMMITMENTS COLORADO PLATEAU ORE Location Age Group Organ Estimated Dose mrem/yr Mill Area including ore pads Interim Soil Cover Active Taffings Cell Taffings Cell Tailings Cell Tailings Cell 4A Tailings Cell 4B Nearest Historical Resident BHV-2 Infant Effective 2.18E-O1 2.14E-02 2.09E-02 4.54E-02 2.53E-02 2.42E-02 Bone 2.69E-O1 1.84E-03 1.90E-03 1.88E-02 1.55E-02 1.53E-02 Avg Lung 8.29E-02 1.61E-03 1.65E-03 1.17E-02 9.36E-03 9.18E-03 Bronchi 2.20EOO 3.31E-O1 3.22E-O1 6.43E-O1 3.39E-O1 3.23E-O1 Ch1d Effective 1.75E-O1 2.14E-02 2.08E-02 4.48E-02 2.49E-02 2.37E-02 Bone 1.91E-O1 1.97E-03 2.04E-03 2.20E-02 1.82E-02 1.80E-02 Avg Lung 1.O1E-O1 1.82E-03 1.87E-03 1.48E-02 1.19E-02 1.17E-02 Bronchi 2.20EOO 3.31E-O1 3.22E-O1 6.43E-O1 3.39E-O1 3.23E-Ol eenage Effective .80E-O1 14E-02 2.09E-02 4.57E-02 2.57E-02 2.44E-02 Bone 6.40E-O1 3.1OE-03 3.28E-03 6.48E-02 5.52E-02 5.52E-02 Avg Lung 8.09E-02 1.78E-03 1.83E-03 1.23E-02 9.71E-03 9.60E-03 Bronchi 2.20EOO 3.31E-O1 3.22E-O1 6.43E-o1 3.39E-Ol 3.23E-O1 Adult Effective 1.65E-O1 2.14E-02 2.08E-02 4.43E-02 2.44E-02 2.33E-02 Bone 2.89E-Ol 2.34E-03 2.45E-03 3.38E-02 2.84E-02 2.82E-02 Avg Lung 5.86E-02 1.70E-03 1.74E-03 9.44E-03 7.21E-03 7.1OE-03 Bronchi 2.20EOO 3.31E-Ol 3.22E-O1 6.43E-O1 3.39E-O1 3.23E-Ol Nearest Resident Infant Effective 6.83E-O1 4.54E-02 4.33E-02 9.67E-02 5.23E-02 4.57E-02 Bone 1.OSEOO 2.46E-03 2.54E-03 4.45E-02 3.61E-02 3.1OE-02 Avg Lung 2.68E-O1 2.30E-03 2.36E-03 2.59E-02 2.07E-02 1.79E-02 Bronchi 5.98EOO 7.20E-Ol 6.84E-O1 1.38EOO 6.95E-O1 6.09E-O1 Child Effective 5.03E-O1 4.54E-02 4.33E-02 9.57E-02 5.14E-02 4.49E-02 Bone 7.12E-O1 2.55E-03 2.65E-03 5.38E-02 4.37E-02 3.74E-02 Avg Lung 3.56E-O1 2.44E-03 2.53E-03 3.52E-02 2.81E-02 2.41E-02 Bronchi 5.98EOO 7.20E-O1 6.84E-O1 1.38EOO 6.95E-O1 6.09E-O1 eenage Effective 5.24E-O1 4.54E-02 4.34E-02 9.81E-02 5.34E-02 4.66E-02 Bone 2.52EOO 3.36E-03 3.58E-03 1.70E-O1 1.40E-Ol 1.19E-O1 Avg Lung 2.85E-O1 2.41E-03 2.50E-03 2.90E-02 2.29E-02 1.96E-02 Bronchi 5.98EOO 7.20E-O1 6.84E-O1 1.38EOO 6.95E-Ol 6.09E-O1 Adult Effective 4.65E-Ol 4.54E-02 4.33E-02 9.41E-02 5.O1E-02 4.38E-02 Bone 1.1OEOO 2.81E-03 2.95E-03 8.54E-02 6.99E-02 5.96E-02 Avg Lung 2.OOE-O1 2.36E-03 2.43E-03 2.13E-02 1.65E-02 1.41E-02 Bronchi 5.98EOO 7.20E-O1 6.84E-Ql 1.38EOO 6.95E-O1 6.09E-O1 34489-10 FINAL April 2008 C-2 SENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE C.1-1 Contd ANNUAL DOSE COMMITMENTS COLORADO PLATEAU ORE Location Age Group Organ Estimated Dose mremlyr Mill Area including ore pads Interim Soil Cover Active Tailings Cell Tailiugs Cell Tailings Cell Taffings Cell 4A Tailings Cell 4B White Mesa Community ant Effective 1.40E-O1 2.23E-02 2.48E-02 5.17E-02 3.15E-02 2.82E-02 Bone 1.16E-O1 2.81E-03 3.05E-03 1.44E-02 l.22E-02 l.08E-02 Avg Lung 4.60E-02 2.26E-03 2.47E-03 l.04E-02 8.61E-03 7.61E-03 Bronchi 1.65EOO 3.36E-O1 3.74E-O1 7.48E-O1 4.43E-O1 3.97E-O1 Child Effective 1.21E-O1 2.23E-02 2.48E-02 5.1 1E-02 3.09E-02 2.77E-02 Bone 7.67E-02 3.14E-03 3.38E-03 l.51E-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 Bronchi l.65EOO 3.36E-O1 3.74E-O1 7.48E-Ol 4.43E-Ol 3.97E-O1 eenage Effective 1.21E-O1 2.24E-02 2.49E-02 5.13E-02 3.1OE-02 2.79E-02 Bone 2.15E-O1 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 7.1OE-03 6.34E-03 Bronchi l.65EOO 3.36E-O1 3.74E-O1 7.48E-O1 4.43E-O1 3.97E-O1 Ad Effective 1.17E-O1 2.23E-02 2.48E-02 5.07E-02 3.05E-02 2.73E-02 Bone 1.06E-O1 4.04E-03 4.33E-03 2.08E-02 l.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 1.65EOO 3.36E-O1 3.74E-O1 7.48E-O1 4.43E-O1 3.97E-O1 Blandrng ant Effective 6.98E-02 8.36E-03 8.50E-03 l.82E-02 l.05E-02 1.04E-02 Bone 7.53E-02 1.17E-03 1.22E-03 7.12E-03 5.86E-03 5.93E-03 Avg Lung 2.45E-02 8.95E-04 9.22E-04 4.57E-03 3.64E-03 3.67E-03 Bronchi 7.34E-O1 1.25E-O1 1.27E-O1 2.53E-O1 l.40E-O1 1.38E-O1 Child Effective 5.72E-02 8.34E-03 8.49E-03 1.79E-02 l.03E-02 1.02E-02 Bone 5.16E-02 l.34E-03 1.39E-03 8.18E-03 6.75E-03 6.83E-03 Avg Lung 2.78E-02 1.15E-03 1.19E-03 5.69E-03 4.5lE-03 4.55E-03 Bronchi 7.34E-O1 l.25E-O1 l.27E-O1 2.53E-Ol l.40E-Ol 1.38E-O1 eenage Effective 5.84E-02 8.37E-03 8.52E-03 l.82E-02 l.06E-02 1.04E-02 Bone 1.65E-O1 2.74E-03 2.88E-03 2.28E-02 l.96E-02 1.99E-02 Avg Lung 2.26E-02 1.1OE-03 l.14E-03 4.84E-03 3.74E-03 3.76E-03 Bronchi 7.34E-Ol 1.25E-O1 1.27E-Ol 2.53E-O1 1.40E-Ol l.38E-Ol Ad ft Effective 5.46E-02 8.33E-03 8.47E-03 1.77E-02 1.O1E-02 9.99E-03 Bone 7.58E-02 1.79E-03 1.87E-03 1.23E-02 1.03E-02 l.05E-02 Avg Lung 1.70E-02 9.99E-04 1.03E-03 3.84E-.03 2.86E-03 2.87E-03 Bronchi 7.34E-O1 1.25E-O1 1.27E-O1 2.53E-O1 1.40E-O1 l.38E-Ol 34489-10 FINAL April 2008 C-3 SENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill C.2.2 40 CFR 190 Regulatory Compliance TABLE C.1-2 40 CFR 190 ANNUAL DOSE COMMITMENTS COLORADO PLATEAU ORE Location Age Group Organ Estimated Dose mremlyr Mill Area including ore pads Interim Soil Cover Active Tailings Cell Tailings Cell Taffings Cell Tailings Cell 4A Tailings Cell 4B Nearest Potential Resident BHVA an Effective 5.22E-O1 O.OOEOO O.OOEOO 1.24E-02 1.03E-02 7.72E-03 Bone 1.76EOO O.OOEOO O.OOEOO 5.43E-02 4.54E-02 3.39E-02 Avg Lung 4.33E-O1 O.OOEOO O.OOEOO 2.83E-02 2.38E-02 1.80E-02 Bronchi 9.30E-04 O.OOEOO O.OOEOO 2.34E-05 1.93E-05 1.41E-05 Child Effective 2.12E-O1 O.OOEOO O.OOEOO 1.1 1E-02 9.23E-03 6.83E-03 Bone 1.20EOO O.OOEOO O.OOEOO 6.80E-02 5.65E-02 4.18E-02 Avg Lung 5.85E-O1 O.OOEOO O.OOEOO 4.19E-02 3.48E-02 2.57E-02 Bronchi 9.30E-04 O.OOEOO O.OOEOO 2.34E-05 1.93E-05 1.41E-05 eenage Effective 2.49E-O1 O.OOEOO O.OOEOO 1.46E-02 1.20E-02 8.86E-03 Bone 4.37EOO O.OOEOO O.OOEOO 2.34E-O1 1.93E-O1 1.41E-O1 Avg Lung 4.61E-O1 O.OOEOO O.OOEOO 3.33E-02 2.75E-02 2.03E-02 Bronchi 9.30E-04 O.OOE-1-OO O.OOE-1-OO 2.34E-05 l.93E-05 1.41E-05 Ad lt Effective .46E-O1 O.OOEOO O.OOEOO 8.99E-03 7.44E-03 5.49E-03 Bone 1.88EOO O.OOEOO O.OOEOO 1.13E-O1 9.35E-02 6.90E-02 Avg Lung 3.1OE-O1 O.OOEOO O.OOEOO 2.24E-02 1.85E-02 1.36E-02 Bronchi 9.30E-04 O.OOEOO O.OOEOO 2.34E-05 1.93E-05 1.41E-05 Nearest Historical Resident BHV-2 an Effective 7.43E-02 O.OOEOO O.OOEOO 3.36E-03 2.99E-03 2.98E-03 Bone 2.54E-O1 O.OOEOO O.OOEOO 1.47E-02 1.31E-02 1.30E-02 Avg Lung 7.02E-02 O.OOEOO O.OOEOO 8.1OE-03 7.28E-03 7.22E-03 Bronchi 1.28E-04 O.OOEOO O.OOEOO 5.68E-06 5.02E-06 5.04E-06 Chld Effective 3.07E-02 O.OOEOO O.OOEOO 2.86E-03 2.53E-03 2.53E-03 Bone 1.76E-O1 O.OOEOO O.OOEOO 1.76E-02 1.56E-02 1.56E-02 Avg Lung 8.70E-02 O.OOEOO O.OOEOO 1.07E-02 9.54E-03 9.53E-03 Bronchi 1.28E-04 O.OOEOO O.OOEOO 5.68E-06 5.02E-06 5.04E-06 eenage Effective 3.58E-02 O.OOEOO O.OOEOO 3.63E-03 3.22E-03 3.23E-03 Bone 6.21E-O1 O.OOEOO O.OOEOO 5.79E-02 5.12E-02 5.14E-02 Avg Lung 6.73E-02 O.OOEOO O.OOEOO 8.37E-03 7.42E-03 7.43E-03 Bronchi 1.28E-04 O.OOEOO O.OOEOO 5.68E-06 5.02E-06 5.04E-06 Ad Effective 2.12E-02 O.OOEOO O.OOEOO 2.27E-03 2.O1E-03 2.02E-03 Bone 2.72E-O1 O.OOEOO O.OOEOO 2.85E-02 2.53E-02 2.53E-02 Avg Lung 4.55E-02 O.OOEOO O.OOEOO 5.66E-03 5.O1E-03 5.02E-03 Bronchi 1.28E-04 O.OOEOO O.OOEOO 5.68E-06 5.02E-06 5.04E-06 34489-10 FINAL April 2008 C-4 SENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE C.1-2 Contd 40 CFR 190 ANNUAL DOSE COMMITMENTS COLORADO PLATEAU ORE Location Age Group Organ Estimated Dose mrem/yr Mill Area including ore pads Interim Soil Cover Active Taffings Cell Taffings Cell Tailings Cell Tailings Cell 4A Taffings Cell 413 Nearest Actual Resident an Effective 3.O1E-01 0.OOE00 0.OOE00 8.77E-03 7.42E-03 6.32E-03 Bone l.02E00 0.OOE00 0.OOE00 3.85E-02 3.25E-02 2.77E-02 Avg Lung 2.43E-01 0.OOE00 0.OOE00 2.04E-02 1.74E-02 1.48E-02 Bronchi 5.32E-04 0.OOE00 0.OOE00 l.61E-05 1.35E-05 1.14E-05 Child Effective 1.21E-01 0.OOE00 0.OOE00 7.79E-03 6.54E-03 5.55E-03 Bone 6.85E-01 0.OOE00 0.OOE00 4.77E-02 4.O1E-02 3.41E-02 Avg Lung 3.30E-0l 0.OOE00 0.OOE00 2.93E-02 2.46E-02 2.09E-02 Bronchi 5.32E-04 0.OOE00 0.OOE00 1.61E-05 1.35E-05 l.14E-05 eenage Effective .42E-0 0.00E00 0.00E00 1.01 E-02 8.46E-03 7.1 6E-03 Bone 2.48E00 0.OOE00 0.OOE00 1.62E-01 1.35E-01 1.14E-01 Avg Lung 2.59E-01 0.OOE00 0.OOE00 2.32E-02 1.94E-02 1.64E-02 Bronchi 5.32E-04 0.OOE00 0.OOE00 1.61E-05 l.35E-05 1.14E-05 Adult Effective 8.31E-02 0.OOE00 0.OOE00 6.27E-03 5.26E-03 4.45E-03 Bone 1.07E00 0.OOE00 0.OOE00 7.88E-02 6.60E-02 5.60E-02 Avg Lung 1.74E-0l 0.OOE00 0.OOE00 1.56E-02 1.31E-02 1.11E-02 Bronchi 5.32E-04 0.OOE00 0.OOE00 1.61E-05 1.35E-05 1.l4E-05 White Mesa Community an Effective 2.98E-02 0.OOE00 0.OOE00 l.90E-03 1.98E-03 l.72E-03 Bone l.02E-01 0.OOE00 0.OOE00 8.21E-03 8.59E-03 7.41E-03 Avg Lung 3.45E-02 0.OOE00 0.OOE00 5.38E-03 5.61E-03 4.85E-03 Bronchi 3.SSE-05 0.OOE00 0.OOE00 1.94E-06 2.05E-06 1.76E-06 Chld Effective l.04E-02 0.OOE00 0.OOE00 1.29E-03 1.36E-03 1.17E-03 Bone 6.1 lE-02 0.OOE00 0.OOE00 8.25E-03 8.66E-03 7.45E-03 Avg Lung 2.86E-02 0.OOE00 0.OOE00 4.82E-03 5.07E-03 4.36E-03 Bronchi 3.85E-05 0.OOE00 0.OOE00 1.94E-06 2.05E-06 l.76E-06 eenage Effective 1.08E-02 0.OOE00 0.OOE00 1.46E-03 l.53E-03 1.32E-03 Bone l.85E-01 0.OOE00 0.OOE00 2.24E02 2.36E-02 2.03E-02 Avg Lung 2.OlE-02 0.OOE00 0.OOE00 3.45E-03 3.63E-03 3.12E-03 Bronchi 3.85E-05 0.OOE00 0.OOE00 1.94E-06 2.05E-06 1.76E-06 Adult Effective 6.70E-03 0.OOE00 0.OOE00 9.71E-04 1.02E-03 8.78E-04 Bone 8.57E-02 0.OOE00 0.OOE00 1.2lE-02 1.27E-02 1.09E-02 Avg Lung 1.41E-02 0.OOE00 0.OOE00 2.42E-03 2.54E-03 2.18E-03 Bronchi 3.85E-05 0.OOE00 0.OOE00 l.94E-06 2.05E-06 1.76E-06 34489-10 FINAL April 2008 C-5 SENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE C.1-2 Contd 40 CFR 190 ANNUAL DOSE COMMITMENTS COLORADO PLATEAU ORE Location Age Group Organ Es timated Dose mremlyr Mill Area including ore pads Interim oil Cover Active Tailings Cell Tailings Cell Tailings Celi Tailings Celi 4A Tailings Cell 4B Blandmg an Effective 2.OOE-02 O.OOEOO O.OOEOO 1.05E-03 l.O1E-03 1.03E-03 Bone 6.79E-02 O.OOEOO O.OOEOO 4.59E-03 4.42E-03 4.52E-03 Avg Lung 1.88E-02 O.OOEOO O.OOEOO 2.63E-03 2.54E-03 2.58E-03 Bronchi 3.17E-05 O.OOEOO O.OOEOO 1.63E-06 1.56E-06 l.61E-06 Child Effective 7.55E-03 O.OOEOO O.OOEOO 8.57E-04 8.23E-04 8.44E-04 Bone 4.34E-02 O.OOEOO O.OOEOO 53 1E-03 5.09E-03 5.23E-03 Avg Lung 2.06E-02 O.OOEOO O.OOEOO 3.22E-03 3.09E-03 3.17E-03 Bronchi 3.17E-05 O.OOEOO O.OOEOO 1.63E-06 1.56E-06 1.61E-06 eenage Effective 8.49E-03 O.OOEOO O.OOEOO 1.07E-03 1.03E-03 i.05E-03 Bone 1.48E-Oi O.OOEOO O.OOEOO 1.69E-02 1.62E-02 i.67E-02 Avg Lung 1.56E-02 O.OOEOO O.OOEOO 2.47E-03 2.38E-03 2.44E-03 Bronchi 3.l7E-05 O.OOEOO O.OOEOO 1.63E-06 1.56E-06 i.61E-06 Ad it Effective 5.05E-03 O.OOEOO O.OOEOO 6.77E-04 6.49E-04 6.67E-04 Bone 6.SOE-02 O.OOEOO O.OQEOO 8.47E-03 8.l3E-03 8.35E-03 Avg Lung 1.06E-02 O.OOEOO O.OOEOO 1.68E-03 1.62E-03 i.66E-03 Bronchi 3.17E-05 O.OOEOO O.OOEOO 1.63E-06 1.56E-06 i.6iE-06 34489-10 FINAL April 2008 C-6 SENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor 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 ore pads and each tailings cell for processing of Arizona Strip ore are provided in Sections C.2.l and C.2.2 respectively C.2.1 R313-15-301 1a Regulatory Compliance TABLE C.2-1 ANNUAL DOSE COMMITMENTS ARIZONA STRIP ORE Location Age Gronp Organ Es timated Dos mrem/yr Mill Area including ore pads Interim Soil Cover Active Taffings Cell Tailings Cell Tailings Cell Tailings Cell 4A Tailings Cell 4B Nearest Potential Resident BHVA Infant Effective 2.82EOO 6.03E-02 5.84E-02 1.52E-Ol 8.64E-02 6.86E-02 Bone 4.59EOO 2.57E-03 2.70E-03 1.47E-Ol 1.21E-O1 9.11E-02 Avg Lung 1.19EOO 2.45E-03 2.55E-03 8.04E-02 6.62E-02 5.04E-02 Bronchi 2.35EOl 9.67E-O1 9.34E-O1 1.87EOO 9.15E-O1 7.45E-Ol Child Effective 2.03EOO 6.03E-02 5.84E-02 1.48E-O1 8.36E-02 6.63E-02 Bone 3.15EOO 2.65E-03 2.79E-03 1.82E-Ol 1.50E-O1 1.11E-Ol Avg Lung 1.57EOO 2.56E-03 2.69E-03 l.16E-Ol 9.42E-02 7.02E-02 Bronchi 2.35EO1 9.67E-O1 9.34E-O1 1.87EOO 9.15E-Ol 7.45E-Ol Teenage Effective 2.12EOO 6.04E-02 5.85E-02 l.57E-Ol 9.07E-02 7.15E-02 Bone l.12EO1 3.28E-03 3.53E-03 6.05E-Ol 4.97E-Ol 3.67E-Ol Avg Lung l.26EOO 2.54E-03 2.66E-03 9.34E-02 7.57E-02 5.63E-02 Bronchi 2.35EO1 9.67E-O1 9.34E-O1 l.87EOO 9.15E-Ol 7.45E-Ol Adult Effective 1.86EOO 6.03E-02 5.84E-02 1.43E-Ol 7.90E-02 6.29E-02 Bone 4.88EOO 2.85E-03________3.03E-03 2.97E-O1 2.44E-Ol 1.8lE-Ol Avg Lung 8.74E-O1 2.50E-03 2.61E-03 6.54E-02 5.27E-02 3.94E-02 Bronchi 2.35EOl 9.67E-Ol 9.34E-Ol 1.87EOO 9.15E-Ol 7.45E-O1 34489-10 FINAL April 2008 C-7 5ENE5 Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE C.2-1 Contd ANNUAL DOSE COMMITMENTS ARIZONA STRIP ORE Location Age Gronp Organ Estimated Dose mrentyr Mill Area inclnding ore pads Interim Soil Cover Active Tailings Cell Taffings Cell Tailings Cell Tailings Cell 4A Tailings Cell 4B Nearest Historical Resident BHV-2 ant Effective 5.57E-O1 2.14E-02 2.09E-02 5.1OE-02 3.04E-02 2.93E-02 Bone 6.85E-O1 1.84E-03 1.90E-03 4.19E-02 3.62E-02 3.59E-02 Avg Lung 2.11E-O1 1.61E-03 1.65E-03 2.47E-02 2.1OE-02 2.07E-02 Bronchi 5.61EOO 3.31E-O1 3.22E-O1 6.44E-O1 3.39E-O1 3.23E-O1 Ch1d Effective 4.45E-O1 2.14E-02 2.08E-02 4.98E-02 2.92E-02 2.81E-02 Bone 4.85E-O1 1.97E-03 2.04E-03 4.96E-02 4.28E-02 4.25E-02 Avg Lung 2.56E-O1 1.82E-03 1.87E-03 3.18E-02 2.71E-02 2.69E-02 Bronchi 5.61EOO 3.31E-O1 3.22E-O1 6.44E-O1 3.39E-O1 3.23E-O1 eenage Effective 4.59E-O1 2.14E-02 2.09E-02 5.18E-02 3.1OE-02 2.99E-02 Bone 1.63EOO 3.1OE-03 3.28E-03 1.54E-O1 1.35E-O1 1.35E-O1 Avg Lung 2.OSE-O1 1.78E-03 1.83E-03 2.58E-02 2.16E-02 2.15E-02 Bronchi 5.61EOO 3.31E-O1 3.22E-O1 6.44E-O1 3.39E-O1 3.23E-O1 AdUt Effective 4.21E-O1 2.14E-02 2.08E-02 4.83E-02 2.79E-02 2.68E-02 Bone 7.36E-O1 2.34E-03 2.45E-03 7.84E-02 6.79E-02 6.78E-02 Avg Lung 1.49E-O1 1.70E-03 l.74E-03 1.87E-02 1.54E-02 1.53E-02 Bronchi 5.61EOO 3.31E-O1 3.22E-O1 6.44E-O1 3.39E-Ol 3.23E-O1 Nearest Resident ant Effective 1.74EOO 4.54E-02 4.33E-02 1.12E-O1 6.49E-02 5.64E-02 Bone 2.67EOO 2.46E-03 2.54E-03 1.05E-O1 8.77E-02 7.48E-02 Avg Lung 6.82E-O1 2.30E-03 2.36E-03 5.88E-02 4.87E-02 4.18E-02 Bronchi 1.53EO1 7.20E-Ol 6.84E-O1 1.38EOO 6.96E-O1 6.1OE-O1 Child Effective 1.28EOO 4.54E02 4.33E-02 1.09E-O1 6.26E-02 5.44E-02 Bone 1.81EOO 2.55E-03 2.65E-03 1.29E-O1 1.07E-O1 9.09E-02 Avg Lung 9.05E-O1 2.44E-03 2.53E-03 8.18E-02 6.73E-02 5.73E-02 Bronchi 1.53EO1 7.20E-O1 6.84E-O1 1.38EOO 6.96E-O1 6.1OE-O1 eenage Effective 1.34EOO 4.54E-02 4.34E-02 1.15E-O1 6.77E-02 5.86E-02 Bone 6.40EOO 3.36E-03 3.58E-03 4.21E-O1 3.50E-O1 2.97E-O1 Avg Lung 7.27E-O1 2.41E-03 2.50E-03 6.62E-02 5.40E-02 4.60E-02 Bronchi 1.53EO1 7.20E-O1 6.84E-Ol 1.38EOO 6.96E-O1 6.1OE-O1 Ad Effective 1.19EOO 4.54E-02 4.33E-02 1.05E-O1 5.94E-02 5.17E-02 Bone 2.80EOO 2.81E-03 2.95E-03 2.08E-O1 1.73E-O1 1.47E-O1 Avg Lung 5.09E-O1 2.36E-03 2.43E-03 4.67E-02 3.78E-02 3.23E-02 Bronchi 1.53EO1 7.20E-O1 6.84E-O1 1.38EOO 6.96E-O1 6.1OE-O1 34489-10 FINAL April 2008 C-8 SENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE C.2-1 Contd ANNUAL DOSE COMMITMENTS ARIZONA STRIP ORE Location Age Group Organ Estimated Dose mrem/yr Mill Area including ore pads Interim Soil Cover Active Tailings Cell Tailings Cell Tailings Cell Tailings Cell 4A Tailings Cell 4B White Mesa Community ant Effective 3.56E-O1 2.23E-02 2.48E-02 5.47E-02 3.47E-02 3.1OE-02 Bone 2.95E-O1 2.81E-03 3.05E-03 2.73E-02 2.57E-02 2.24E-02 Avg Lung 1.17E-O1 2.26E-03 2.47E-03 1.89E-02 1.74E-02 1.53E-02 Bronchi 4.20EOO 3.36E-O1 3.74E-O1 7.48E-O1 4.43E-O1 3.97E-O1 Child Effective 3.07E-O1 2.23E-02 2.48E-02 5.32E-02 3.32E-02 2.96E-02 Bone 1.96E-O1 3.14E-03 3.38E-03 2.80E-02 2.63E-02 2.29E-02 Avg Lung 1.08E-O1 2.76E-03 2.99E-03 1.85E-02 1.66E-02 1.46E-02 Bronchi 4.20EOO 3.36E-O1 3.74E-O1 7.48E-O1 4.43E-O1 3.97E-O1 eenage Effective 3.09E-O1 2.24E-02 2.49E-02 5.37E-02 3.36E-02 3.OOE-02 Bone 5.46E-O1 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 1.13E-02 Bronchi 4.20EOO 3.36E-O1 3.74E-O1 7.48E-O1 4.43E-O1 3.97E-O1 Ad Effective 2.97E-O1 2.23E-02 2.48E-02 5.23E-02 3.22E-02 2.88E-02 Bone 2.70E-O1 4.04E-03 4.33E-03 3.96E-02 3.76E-02 3.27E-02 Avg Lung 6.77E-02 2.47E-03 2.69E-03 1.18E-02 9.87E-03 8.70E-.03 Bronchi 4.20EOO 3.36E-O1 3.74E-O1 7.48E-O1 4.43E-O1 3.97E-O1 Bl an ing ant Effective 1.78E-O1 8.36E-03 8.50E-03 1.99E-02 1.22E-02 1.21E-02 Bone 1.92E-O1 1.17E-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 1.87EOO 1.25E-O1 1.27E-O1 2.53E-O1 1.40E-O1 1.38E-O1 Chid Effective 1.46E-O1 8.34E-03 8.49E-03 1.94E-02 1.17E-02 1.16E-02 Bone 1.31E-O1 1.34E-03 1.39E-03 1.65E-02 1.48E-02 1.51E-02 Avg Lung 7.09E-02 1.15E-03 1.19E-03 1.08E-02 9.42E-03 9.59E-03 Bronchi 1.87EOO 1.25E-O1 1.27E-O1 2.53E-O1 1.40E-O1 1.38E-O1 eenage Effective 1.49E-O1 8.37E-03 8.52E-03 2.OOE-02 1.23E-02 1.22E-02 Bone 4.19E-O1 2.74E-03 2.88E-03 4.92E-02 4.49E-02 4.60E-02 Avg Lung 5.74E-02 1.1 OE-03 14E-03 8.81 E-03 7.54E-03 7.67E-03 Bronchi 1.87EOO 1.25E-O1 1.27E-O1 2.53E-O1 1.40E-O1 1.38E-O1 Ad Effective 1.40E-O1 8.33E-03 8.47E-03 1.89E-02 1.13E-02 1.12E-02 Bone 1.93E-O1 1.79E-03 1.87E-03 2.56E-02 2.31E-02 2.35E-02 Avg Lung 4.34E-02 9.99E-04 1.03E-03 6.58E-03 5.48E-03 5.56E-03 Bronchi 1.87EOO 1.25E-O1 1.27E-O1 2.53E-O1 1.40E-O1 1.38E-O1 34489-10 FINAL April 2008 C-9 SENES Consultants Limited Proposed Development of New Tailings Cell 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 Location Age Group Organ Estimated Dose mremlyr Mill Area including ore pads Interim Soil Cover Active Tailings Cell Tailings Cell Tailings Cell Tailings Celi 4A Tailings Celi 4B Nearest Potential Resident BHV-1 Infant Effective l.33EOO O.OOEOO O.OOEOO 3.15E-02 2.63E-02 1.97E-02 Bone 4.51EOO O.OOEOO O.OOEOO 1.38E-O1 1.16E-Ol 8.63E-02 Avg Lung 1.1OEOO O.OOEOO O.OOEOO 7.22E-02 6.07E-02 4.59E-02 Bronchi 2.37E-03 O.OOEOO O.OOEOO 5.96E-05 4.90E-05 3.59E-O5 Child Effective 5.40E-O1 O.OOEOO O.OOEOO 2.84E-02 2.35E-02 1.74E-02 Bone 3.06EOO O.OOEOO O.OOEOO l.73E-O1 1.44E-Ol 1.07E-Ol Avg Lung .49EOO O.OOEOO O.OOEOO .07E-O1 8.86E-02 6.55E-02 Bronchi 2.37E-03 O.OOEOO O.OOEOO 5.96E-05 4.90E-05 3.59E-O5 eenage Effective 6.36E-O1 O.OOEOO O.OOEOO 3.71E-02 3.07E-02 2.26E-02 Bone l.11EOl O.OOEOO Q.OOEOO 5.95E-O1 4.9lE-Ol 3.61E-O1 Avg Lung 1.17EOO O.OOEOO O.OOEOO 8.48E-02 7.OlE-02 5.16E-02 Bronchi 2.37E-03 O.OOEOO O.OOEOO 5.96E-05 4.90E-05 3.59E-05 Adult Effective 3.72E-O1 O.OOEOO O.OOEOO 2.29E-02 1.89E-02 1.40E-02 Bone 4.80EOO O.OOEOO O.OOEOO 2.88E-O1 2.38E-O1 l.76E-O1 Avg Lung 7.89E-Ol O.OOEOO O.OOEOO 5.70E-02 4.72E-02 3.48E-02 Bronchi 2.37E-03 O.OOEOO O.OOEOO 5.96E-05 4.90E-05 3.59E-05 Nearest Historical Resident BHV-2 Infant Effective 1.90E-O1 O.OOEOO O.OOEOO 8.54E-03 7.63E-03 7.59E-03 Bone 6.49E-O1 O.OOEOO O.OOEOO 3.74E-02 3.34E-02 3.33E-02 Avg Lung 1.79E-O1 O.OOEOO O.OOEOO 2.07E-02 1.86E-02 1.84E-02 Bronchi 3.27E-04 O.OOEOO O.OOEOO 1.45E-05 1.28E-O5 1.28E-05 Child Effective 7.82E-02 O.OOEOO O.OOEOO 7.27E-03 6.46E-03 6.46E-03 Bone 4.48E-O1 O.OOEOO O.OOEOO 4.48E-02 3.98E-02 3.98E-02 Avg Lung 2.2lE-Ol O.OOEOO O.OOEOO 2.73E-02 2.42E-02 2.43E-02 Bronchi 3.27E-04 O.OOEOO O.OOEOO 1.45E-05 1.28E-05 l.28E-05 Teenage Effective 9.1 1E-02 O.OOEOO O.OOEOO 9.26E-03 8.21E-03 8.22E-03 Bone l.58EOO O.OOEOO O.OOEOO 1.47E-Ol l.30E-O1 1.31E-O1 Avg Lung 1.71E-O1 O.OOEOO O.OOEOO 2.13E-02 l.89E-02 l.90E-02 Bronchi 3.27E-04 O.OOEOO O.OOEOO l.45E-05 1.28E-05 1.28E-O5 Ad Effective 5.39E-02 O.OOEOO O.0OEOO 5.80E-03 1SE-03 14E-03 Bone 6.93E-Ol O.OOEOO O.OOEOO 7.27E-02 6.45E-02 6.45E-02 Avg Lung l.16E-O1 O.OOEOO O.OOEOO 1.44E-02 l.28E-02 l.28E-02 Bronchi 3.27E-04 O.OOEOO O.OOEOO l.45E-05 1.28E-05 l.28E-05 34489-10 FINAL-April 2008 C-1O SENES Consultants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE C.2-2 Contd 40 CFR 190 ANNUAL DOSE COMMITMENTS ARIZONA STRIP ORE Location Age Group Organ Estimated Dose mremlyr Miii Area including ore pads Interim Soil Cover Active Tailings Cell Tailings Cell Tailings Cell Tailings Cell 4A Taillugs Cell 4B Resident an Effective 7.69E-O1 O.OOEOO O.OOEOO 2.23E-02 1.89E-02 1.61E-02 Bone 2.60EOO O.OOEOO O.OOEOO 9.79E-02 8.29E-02 7.06E-02 Avg Lung 6.19E-O1 O.OOEOO O.OOEOO 5.19E-02 4.43E-02 3.79E-02 Bronchi .36E-03 O.OOEOO O.OOEOO 4.1 1E-05 3.43E-05 2.90E-05 Child Effective 3.08E-O1 O.OOEOO O.OOEOO 1.98E-02 1.67E-02 1.41E-02 Bone 1.75EOO O.OOEOO O.OOEOO 1.21E-O1 1.02E-O1 8.66E-02 Avg Lung 8.41E-O1 O.OOEOO O.OOEOO 7.47E-02 6.27E-02 5.32E-02 Bronchi 1.36E-03 O.OOEOO O.OOEOO 4.11E-05 3.43E-05 2.90E-05 eenage Effective 3.62E-O1 O.OOEOO O.OOEOO 2.57E-02 2.16E-02 1.83E-02 Bone 6.33EOO O.OOEOO O.OOEOO 4.13E-O1 3.44E-O1 2.91E-O1 Avg Lung 6.63E-O1 O.OOEOO O.OOEOO 5.90E-02 4.94E-02 19E-02 Bronchi 1.36E-03 O.OOEOO O.OOEOO 4.1 1E-05 3.43E-05 2.90E-05 Adult Effective 2.12E-O1 O.OOEOO O.OOEOO 1.60E-02 1.34E-02 1.13E-02 Bone 2.72EOO O.OOEOO O.OOEOO 2.O1E-O1 1.68E-O1 1.42E-O1 Avg Lung 4.44E-Ol O.OOEOO O.OOEOO 3.97E-02 3.32E-02 2.82E-02 Bronchi 1.36E-03 O.OOEOO O.OOEOO 4.1 1E-05 3.43E-05 2.90E-05 White Mesa Community Infant Effective 7.59E-02 O.OOEOO O.OOEOO 4.83E-03 5.06E-03 4.36E-03 Bone 2.59E-O1 O.OOEOO O.OOEOO 2.09E-02 2.19E-02 1.89E-02 Avg Lung 8.79E-02 O.OOEOO O.OOEOO 1.37E-02 1.44E-02 1.24E-02 Bronchi 9.81E-O5 O.OOEOO O.OOEOO 4.94E-06 5.23E-06 4.48E-06 Child Effective 2.66E-02 O.OOEOO O.OOEOO 3.29E-03 3.45E-03 2.96E-03 Bone 1.56E-O1 O.OOEOO O.OOEOO 2.1OE-02 2.21E-02 1.90E-02 Avg Lung 7.28E-02 O.OOEOO O.OOEOO 1.23E-02 1.29E-02 1.1 1E-02 Bronchi 9.81E-05 O.OOEOO O.OOEOO 4.94E-06 5.23E-06 4.48E-06 eenage Effective 2.75E-02 O.OOEOO O.OOEOO 3.71E-03 3.91E-03 3.36E-03 Bone 4.73E-O1 O.OOEOO O.OOEOO 5.70E-02 6.OOE-02 5.16E-02 Avg Lung 5.1 1E-02 O.OOEOO O.OOEOO 8.78E-03 9.24E-03 7.95E-03 Bronchi 9.81E-05 O.OOEOO O.OOEOO 4.94E-06 5.23E-06 4.48E-06 Ad Effective 1.70E-02 O.OOEOO O.OOEOO 2.47E-03 2.60E-03 2.24E-03 Bone 2.19E-O1 O.OOEOO O.OOEOO 3.07E-02 3.23E-02 2.79E-O2 Avg Lung 3.60E-02 O.OOEOO O.OOEOO 6.15E-03 6.47E-03 5.56E-03 Bronchi 9.81E-05 O.OOEOO O.OOEOO 4.94E-06 5.23E-06 4.48E-06 34489-10 FINAL-April 2008 C-il SENES Consullants Limited Proposed Development of New Tailings Cell 4Bfor White Mesa Uranium Mill TABLE C.2-2 Contd 40 CFR 190 ANNUAL DOSE COMMITMENTS ARIZONA STRIP ORE Location Age Group Organ Estimated Dose mrem/yr Mill Area including ore pads Interim oil Cover Active Tailings Cell Tailings Cell Tailings Cell Tailings Cell 4A Tailings Cell 4B Blandmg an Effective 5.12E-02 O.OOEOO O.OOEOO 2.68E-03 2.57E-03 2.63E-03 Bone 1.73E-O1 O.OOEOO O.OOEOO 1.17E-02 1.12E-02 1.1SE-02 Avg Lung 4.77E-02 O.OOEOO O.OOEOO 6.71E-03 6.45E-03 6.58E-03 Bronchi 8.07E-05 O.OOEOO O.OOEOO 4.16E-06 3.99E-06 4.1 1E-06 Child Effective 1.93E-02 O.OOEOO O.OOEOO 2.19E-03 2.1OE-03 2.15E-03 Bone 1.1OE-O1 O.OOEOO O.OOEOO 1.35E-02 1.30E-02 1.33E-02 Avg Lung 5.25E-02 O.OOEOO O.OOEOO 8.21E-03 7.87E-03 8.07E-03 Bronchi 8.07E-05 O.OOEOO O.OOEOO 4.16E-06 3.99E-06 4.1 1E-06 eenage Effective 2.17E-02 O.OOEOO O.OOEOO 2.73E-03 2.61E-03 2.69E-03 Bone 3.77E-O1 O.OOEOO O.OOEOO 4.32E-02 4.14E-02 4.25E-02 Avg Lung 3.97E-02 O.OOEOO O.OOEOO 6.31E-03 6.04E-03 6.21E-03 Bronchi 8.07E-05 O.OOEOO O.OOEOO 4.16E-06 3.99E-06 4.1 1E-06 Ad Effective 1.29E-02 O.OOEOO O.OOEOO 1.72E-03 1.66E-03 1.70E-03 Bone 1.66E-O1 O.OOEOO O.OOEOO 2.16E-02 2.07E-02 2.13E-02 Avg Lung 2.71E-02 O.OOEOO O.OOEOO 4.29E-03 4.11E-03 4.23E-03 Bronchi 8.07E-O5 O.OOEOO O.OOEOO 4.16E-06 3.99E-06 4.1 1E-06 34489-10 FINAL April 2008 c-i SENES Consultants Limited Appendix SENES Consultants Limited 121 Granton Drive Unit 12 Richmond Hill Ontario Canada L4B3N4 Tel 905 764-9380 Fax 905 764-9386 E-mail senes@senes.ca Web Site http/Iwww.senes.ca 34489-10 28 April 2008 Mr Steven Landau Manager Environmental Affairs Denison Mines USA Corp 1050 17th Street Suite 950 Denver CO 80265 Subject Review of Environmental Radiological Monitoring Program for the White Mesa Uranium Mill Dear Mr Landau This letter report provides review of the environmental radiological monitoring program at Denisons 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 Cell 4B In preparing this report we directly reference and use information in Mills 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 Mills meteorological station show that the predominant wind directions during the past four years 2004-2007 were blowing from the north-north-easteriy and northerly directions Turk 2007 and Landau 2008b The 2007 annual frequency distribution is presented graphically in Figure 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 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 28Apr11 2008 Letter to Landau Continued Page characteristics of winds from the south and station BHV-4 and BHV-6 will detect radiological characteristics of winds from the north The current radiological monitoring program at the Mill has the following environmental media and conditions DUSA 2007 and 2008 Air particulate radionuclide concentrations from the following sampling stations see Figure North East and South of the Mill site BHV-l BHV-2 north BHV-5 east BHV-4 south BHV-3 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 External direct gamma radiation measurements at air monitoring stations BHV- BHV-2 BHV-3 BHV-4 aBHV-5 and BHV-6 Radon-222 is measured at air monitoring stations BHV-1 BHV-2 BHV-4 BHV-5 and BHV-6 Vegetative uptake of radionuclides at three periphery locations Stack releases from the facilitys air emissions sources Annual Surface water samples from within Cottonwood Creek and when flowing the Westwater Creek drainage both located west of the Mill Annual Soil radionuclide activity obtained near the air monitoring station 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 of the 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 mIs 34489-10 28Apr11 2008 Letter to Landau Continued Page The measured activity of airborne particulate U-nat Th-230 Ra-226 and Pb-210 at all monitoring stations shown in Figure were well below regulatory Effluent Concentration Limits ECLs and the Mills 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 Vt 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-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 of Ra-226 or Pb-210 in vegetation and are well within the range of previous 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 U-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 DUSA 2007 did not show any anomalies from the historical data which indicates the Mills 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 28Apr11 2008 Letter to Landau Continued Page directions based on the meteorological data from the last four years As 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 of the 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 NRCs 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 of radioactive 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 Chambers Ph.D Vice-President Director of Radioactivity and Risk Studies 34489-10 28Apr11 2008 Letter to Landau Continued Page REFERENCES Denison Mines USA Corp DUSA 2007 White Mesa Uranium Mill Radioactive Materials License UT900479 Semi-Annual Effluent Monitoring Report Januaiy through June 2007 December Denison Mines USA Corp DUSA 2008 White Mesa Uranium Mill Radioactive Materials License UT900479 Semi-Annual Effluent Monitoring Report July through Decemeber 2007 March Landau 2008a E-mail to Chambers FW 34489 Environmental Rad Monitoring at White Mesa Mill Landau 2008b E-mail to Chambers 2007 Windrose Turk 2007 E-mail to Chambers FW Additional Weather Information United States Nuclear Regulatory Commission NRC 1980 Regulatory Guide 4.14 Radiological Effluent and Environmental Monitoring at Uranium Mills-Rev /1 Propvty Soundsy Air Monitoring Stalions Reservation Boundsy Canyon Rim SOURCE Adapted from Mftes USA Coip Flgwe 33-2.dwg Febmay 2007 iii aS FaT 34489-10 28 April 2008 Letter to Landau Continued FIGURE LOCATION OF AIR MONITORING STATIONS Page SJY Ls BHV-2 /j BHV-1 1- PS BHV-4 Pa \i\ ..Sj -L 34489-10 28Apr11 2008 Letter to Landau tontinued FIGURE 2007 WIND ROSE PLOT Page aisli 4Th fl Nfl flfl D.M...Sn flJ114 CapaaOouiMW Figure tin rn In MTtUN 201846 _PDfl iiWMssaMJss DWcDa $L I.- I2% SW EAst __...4 n.h ti-u ti-ti 34489-10 28Apr11 2008 Letter to Landau Continued Page FIGURE LOCATION OF AIR MONITORING STATIONS BH3I -0 proPrY Bounday Air Monitoring Stations Reservation Soundaiy Canyon Rim SOURCE Adapted from Denison Mines USA Corp. Figure 3.3-2.dwg. February 2001 III acid II IWT