# Technical and Regulatory Support to Develop a Rulemaking to Potentially Modify the NESHAP Subpart W Standard for Radon Emissions from Operating Uranium Mills (40 CFR 61.250)

U.S. Environmental Protection Agency

Office of Radiation and Indoor Air

1200 Pennsylvania Avenue, N.W. Washington, DC 20460 February 2014TABLE OF CONTENTS

Acronyms and Abbreviations .................................................................................................... ... vii

1.0 Executive Summary ............................................................................................................. 1

1.1 Introduction, History, and Basis ..............................................................................1

1.2 The Uranium Extraction Industry Today .................................................................2

1.3 Current Understanding of Radon Risk .....................................................................3

1.4 Evaluation of Subpart W Requirements ..................................................................4

1.5 Economic Impacts ....................................................................................................5

2.0 Introduction, History, and Basis ..........................................................................................6

2.1 Document Contents and Structure ...........................................................................7

2.1.1 The Uranium Extraction Industry Today .....................................................7

2.1.2 Current Understanding of Radon Risk .........................................................8

2.1.3 Evaluation of Subpart W ..............................................................................8

2.1.4 Economic Impact Analysis ..........................................................................8

2.2 History of the Development of the Subpart W NESHAP ........................................9

2.2.1 The 1977 Amendments to the Clean Air Act .............................................11

2.2.2 Regulatory Activities between 1979 and 1987 ..........................................11

2.2.3 Regulatory Activities between 1987 and 1989 ..........................................13

2.2.4 1989 Radionuclide NESHAPs Reco nsideration Rulemaking....................13

2.2.5 1990 Amendments to th e Clean Air Act ....................................................14

2.3 Basis for the Subpart W 1989 Risk Assessment and Results ................................15

2.3.1 Existing Impoundments .............................................................................16

2.3.2 New Impoundments ...................................................................................17

3.0 The Uranium Extraction Industry Today: A Summary of the Existing and Planned Uranium Recovery Projects ...............................................................................................17

3.1 The Uranium Market ..............................................................................................18

3.2 Conventional Uranium Mining and Milling Operations ........................................21

3.2.1 Sweetwater Mill, Kennecott Mining Company, Red Desert, Wyoming....................................................................................................23

3.2.2 White Mesa Mill, Energy Fuel s Corporation, Blanding, Utah ..................25

3.2.3 Shootaring Canyon Mill, Uranium One Incorporated, Garfield County, Utah ..............................................................................................28

3.2.4 Piñon Ridge Mill, Bedrock, Colorado .......................................................29

3.2.5 Conventional Mill Tailings Impoundments and Radon Flux Values ........30

3.3 In-Situ Leach Uranium Recovery (Solution Mining) ............................................31

3.3.1 Radon Emission from Evaporation and/or Holding Ponds ........................36

3.4 Heap Leaching .......................................................................................................38

3.4.1 Sheep Mountain Mine, Energy Fuel s, Fremont County, Wyoming ..........40

3.5 Method 115 to Monitor Radon Emissi ons from Uranium Tailings .......................41

4.0 Current Understanding of Radon Risk ...............................................................................444.1 Radon and Dose Definitions ..................................................................................44

4.2 Radon Risk Factors ................................................................................................45

4.3 Computer Models...................................................................................................46

4.4 Uranium Recovery Facility Radon Dose and Risk Estimates ...............................47

4.5 Summary of Radon Risk ........................................................................................51

5.0 Evaluation of Subpart W Requirements ............................................................................51

5.1 Items Reviewed and Key Issues ............................................................................51

5.1.1 Existing and Proposed Uranium Recovery Facilities ................................52

5.1.2 RCRA Comparison ....................................................................................54

5.1.3 Regulatory History .....................................................................................55

5.1.4 Tailings Impoundment Technologies ........................................................55

5.1.5 Radon Measurement Methods ...................................................................56

5.1.6 Risk Assessment ........................................................................................60

5.2 Uranium Recovery Source Categories ...................................................................61

5.3 The GACT Standard ..............................................................................................61

5.4 Uranium Recovery Categories and GACT ............................................................63

5.5 Other Issues ............................................................................................................65

5.5.1 Extending Monitoring Requirements .........................................................65

5.5.2 Clarification of the Term “Operation” .......................................................66

5.5.3 Clarification of the Term “Standby” ..........................................................66

5.5.4 The Role of Weather Events ......................................................................67

6.0 Economic Impacts Associated with Re vision/Modification of the Subpart W

Standard ...................................................................................................................... .......68

6.1 1989 Economic Assessment ..................................................................................69

6.1.1 Reducing Post-Closure Radon Emissions from 20 pCi/(m 2 -sec) ..............70

6.1.2 Reducing Radon Emissions During Op eration of Existing Mills ..............71

6.1.3 Promulgating a Work Practice St andard for Future Tailings Impoundments ............................................................................................71

6.1.4 Economic Impacts ......................................................................................74

6.2 U 3 O 8 Recovery Baseline Economics .....................................................................74

6.2.1 Conventional Mill Cost Estimate ...............................................................76

6.2.2 Heap Leach Facility Cost Estimate ............................................................79

6.2.3 In-Situ Leach (Long) Facility Cost Estimate .............................................81

6.2.4 In-Situ Leach (Short) Facility Cost Estimate .............................................83

6.2.5 Cost Estimate Sensitivities .........................................................................84

6.2.6 Annual Total U 3 O 8 Cost Estimates ............................................................87

6.3 Economic Assessment of Proposed GACT Standards ...........................................90

6.3.1 Method 115, Radon Flux Monitoring ........................................................90

6.3.2 Double Liners for Nonconventional Impoundments .................................93

6.3.3 Maintaining 1 Meter of Water in Nonconventional Impoundments ........100

6.3.4 Liners for Heap Leach Piles .....................................................................105

6.3.5 Maintaining Heap Leach Piles at 30% Moisture .....................................1086.3.6 Summary of Proposed GACT Standards Economic Assessment ............112

6.4 Environmental Justice ..........................................................................................115

6.4.1 Racial Profile for Uranium Recovery Facility Areas ...............................115

6.4.2 Socioeconomic Data for Uranium Recovery Facility Areas ....................117

6.5 Regulatory Flexibility Act ...................................................................................118

7.0 References .................................................................................................................... ....120

LIST OF TABLES

Table 1: U 3 O 8 Market Value and Cost to Produce (Nondiscounted)..............................................6

Table 2: Partial Timeline of EPA’s Radiation Standards ...............................................................9

Table 3: Conventional Uranium Mining and Milling Operations ................................................22

Table 4: Proposed New Conventional Uranium Milling Facilities ..............................................23

Table 5: Sweetwater Mill Radon Flux Testing Results ................................................................24

Table 6: White Mesa Mill’s Annual Ra don Flux Testing, Tailings Cells 2 & 3 ..........................26

Table 7: Mill Tailings Impoundments and Average/Calculated Radon Flux Values* .................31

Table 8: Operati ng ISL Facilities ............................................................................................ ......33

Table 9: ISL Facilities That Are Restarting, Expanding, or Pl anning for New Operations .........34

Table 10: ISL Evaporation Pond Data Compilation .....................................................................35

Table 11: Anticipated New Heap Leach Facilities .......................................................................38

Table 12: Uranium Recovery Sites Analyzed ...............................................................................47

Table 13: Calculated Maximum Total A nnual RMEI, Population Dose and Risk .......................49

Table 14: Calculated Average Total A nnual RMEI, Population Dose and Risk ..........................49

Table 15: Dose and Risk to an Average Member of the Population ............................................50

Table 16: Current Pre-December 15, 1989 Conventional Impoundments ...................................53

Table 17: Radon Risk Resulting from Altern ative Work Practices (Committed Cancers) ..........73
Table 18: Uranium Recovery Baseline Economics (Nondiscounted) ..........................................75

Table 19: Conventiona l Mill Cost Estimate ..................................................................................77

Table 20: Heap Leach F acility Cost Estimate ...............................................................................80

Table 21: In-Situ Leach (Long) Facility Cost Estimate ................................................................82

Table 22: In-Situ Leach (Shor t) Facility Cost Estimate ................................................................84

Table 23: Uranium Ore Grade .................................................................................................. ....85

Table 24: U 3 O 8 Market Value and Cost to Produce (Nondiscounted) ..........................................85

Table 25: Assumed Case 4 U 3 O 8 Production Breakdown by Mine Type .....................................89

Table 26: Case 4 (Mixed Uranium Rec overy Facilities) Economic Projections (Nondiscounted) ........................................................................................................89

Table 27: Data Used to Develop Method 115 Unit Costs ............................................................92

Table 28: Method 115 Unit Costs .............................................................................................. ...92
Table 29: Geomembrane (HDPE) Liner Unit Costs .....................................................................94Table 30: Drainage Laye r (Geonet) Unit Costs ............................................................................94

Table 31: Geosynthetic Clay Liner (GCL) Unit Costs .................................................................95

Table 32: Nonconventional Impoundment Areas .........................................................................96

Table 33: Base Facility Nonconventiona l Impoundment Double Liner Capital and

Installation Costs .......................................................................................................97

Table 34: Mean Base Facility Nonconven tional Impoundment Double Liner Capital and

Installation Cost Breakdown .....................................................................................97

Table 35: Projected Nonconventional Impoundment Double Liner Annualized Capital and Installation Costs ................................................................98

Table 36: Base Facility Nonconven tional Impoundment Double Liner Annual Operation and Maintenance Costs .............................................................................98

Table 37: Projected Nonconventional Impoundment Double Liner Annual Operation and Maintenance Costs ................................................................99

Table 38: Projected Nonconventional Impoundment Double Liner Total Annual Costs .............99

Table 39: Comparison of Double Liner to Total U 3 O 8 Production Costs .....................................99

Table 40: Makeup Water Unit Costs ..........................................................................................10 2
Table 41: Summary of Base Facility Characteristics ..................................................................103

Table 42: Base Facility Annual Makeup Water Cost .................................................................103

Table 43: Base Facility Ma keup Water Cost per Pound of U 3 O 8 ...............................................103
Table 44: Projected Annual Makeup Water Cost .......................................................................104

Table 45: Comparison of Cost to Maintain 1 Meter of Water in the Impoundments to Total

U 3 O 8 Production Cost ..............................................................................................104

Table 46: Annual Dose and Risk Reduction fr om Maintaining 1 Mete r of Water in the Impoundments .........................................................................................................105

Table 47: Heap Pile Double Line r Capital and Installation Costs ..............................................107

Table 48: Mean Heap Pile Doubl e Liner Capital Cost Breakdown ............................................107

Table 49: Heap Pile Double Liner Annual Costs ........................................................................108

Table 50: Heap Pile Annual Makeup Water Cost .......................................................................110

Table 51: Projected Annual H eap Pile Makeup Water Cost .......................................................111

Table 52: Annual Dose and Risk Comparison for Maintaining 30% Mo isture Content in the Heap Pile ............................................................................................................111

Table 53: Proposed GACT Standards Costs per Pound of U 3 O 8 ................................................112
Table 54: Proposed GACT Standards Re ference Facility Annual Costs ....................................113

Table 55: Proposed GACT Standards National Annual Costs ...................................................113

Table 56: Proposed GACT Standa rds Summed National Costs .................................................114

Table 57: Racial Profile for Uran ium Recovery Facility Counties .............................................116

Table 58: Regional and Na tional Racial Profiles ........................................................................116

Table 59: Socioeconomic Data for Ur anium Recovery Facility Counties .................................117LIST OF FIGURES

Figure 1: Historical Uranium Prices .......................................................................................... ...19
Figure 2: Uranium Production and Demand from 1945 to 2005 ..................................................20

Figure 3: Uranium Supply Scenario from 2008 to 2030 ...............................................................20

Figure 4: Typical Conventional Uranium Mill .............................................................................21

Figure 5: Sweetwater – Aerial View ........................................................................................... ..24
Figure 6: White Mesa – Aerial View ........................................................................................... .26
Figure 7: Shootaring Canyon – Aerial View ................................................................................28

Figure 8: Piñon Ridge – Aerial View .......................................................................................... .30
Figure 9: In-Situ Leach Uran ium Recovery Flow Diagram .........................................................32

Figure 10: Typical Heap-Leaching Uranium Recovery Facility ..................................................40

Figure 11: Sheep Mount ain – Aerial View ...................................................................................41

Figure 12: Uranium Decay Series .............................................................................................. ...44
Figure 13: Diffusion Coefficient as a Function of Moisture Saturation .......................................57

Figure 14: Emanation Coefficient as a Func tion of Moisture Content and Moisture

Saturation ...................................................................................................................5 9
Figure 15: Radon Flux as a Function of Mo isture Saturation and Moisture Content ...................60

Figure 16: U.S. Average Annual Precipitation .............................................................................67

Figure 17: U.S. Mean Annual Evaporation ..................................................................................68

Figure 18: Estimated Cash Balance – Reference Cases ................................................................78

Figure 19: Cumulative U 3 O 8 Projections – Reference Cases .......................................................79

Figure 20: Estimated Cash Balance – Sensitivity Cases ...............................................................86

Figure 21: Cumulative U 3 O 8 Projections – Sensitivity Cases ......................................................87

Figure 22: Nuclear-Generated Electricity Projections ..................................................................88

Figure 23: U.S. and Fo reign Contribution to U 3 O 8 Purchases ......................................................90
Figure 24: Typical Double-Lined Impound ment with Leak Collection Layer .............................93

Figure 25: Typical Double Liner Anchor System .........................................................................96

Figure 26: Typical Heap Pile Liner ........................................................................................... .106ACRONYMS AND ABBREVIATIONS

ACE Army Corps of Engineers

AEA Atomic Energy Act

AIRDOS AIR DOSe

ALARA as low as reasonably achievable

AMC American Mining Congress

ANPR Advance Notice of Proposed Rulemaking

BaCl 2 barium chloride

BEIR Biological Effects of Ionizing Radiation

BID background information document

CAA Clean Air Act

CAP88 Clean Air Act Assessment-1988

CFR Code of Federal Regulations

CHP certified health physicist

Ci/yr curies per year

cm centimeter

cm/sec centimeter per second

cm 2 /sec square centimeter per second

CPI consumer price index

CPP Central Processing Plant

DARTAB Dose And Risk TABulation

DOE Department of Energy

EDF Environmental Defense Fund

EIA Energy Information Administration

EIS environmental impact statement

EPA Environmental Protection Agency

E-PERM Electric Passive Environmental Radon Monitor

FGR Federal Guidance Report

FR Federal Register

ft feet

g/cc gram per cubic centimeter

G&A general and administrativeGACT generally available control technology

GCL geosynthetic clay liner

GHG Greenhouse Gas

gpm gallons per minute

gpm/ft 2 gallons per minute per square foot

H 2 SO 4 sulfuric acid

HAP hazardous air pollutant

HDPE high-density polyethylene

HRTM Human Respiratory Tract Model

ICRP International Commi ssion on Radiological Protection

in/yr inches per year

ISL in-situ leach

ISR in-situ recovery

km kilometer

L liter

LAACC large-area activated charcoal collector

lb pound

LCF latent cancer fatalities

L/d liters per day

LLDPE linear low-density polyethylene

LoC line of credit

m 2 square meters

m 3 /hr cubic meters per hour

m/sec meters per second

MACT maximum achievab le control technology

MARSSIM Multi-Agency Radiation Surv ey and Site Investigation Manual

mi mile

MIR maximum individual risk

mph miles per hour

mrem millirem

mSv millisievert

N.C. not calculated

NESHAP National Emission Standard for Hazardous Air PollutantsN.G. not given

NMA National Mining Association

NRC Nuclear Regulatory Commission

NRDC Natural Resources Defense Council

O&M operation and maintenance

ORISE Oak Ridge Institute for Science and Education

pCi picocurie

pCi/(ft 2 -sec) picocurie per square foot per second

pCi/g picocurie per gram

pCi/L picocurie per liter

pCi/(m 2 -sec) picocurie per square meter per second

PIPS passive implanted planar silicon

POO Plan of Operation

PVC polyvinyl chloride

R&D research and development

Ra radium

RADRISK RADiation RISK

RCRA Resource Conservation and Recovery Act

rem roentgen equivalent in man

RMEI reasonably maximally exposed individual

Rn radon

RSO radiation safety officer

SC Sierra Club

SF square foot

tpd tons per day

U uranium

U 3 O 8 triuranium octoxide

UMTRCA Uranium Mill Tailings Remedial Control Act

WCS Waste Control Specialists, LLC

WL working level

WLM working level month

ZnS(Ag) silver doped zinc sulfide1 1.0 EXECUTIVE SUMMARY

The purpose of this report is to present the reader with an und erstanding of the facilities being regulated under this National Emission Standa rd for Hazardous Air Pollutant (NESHAP). The report also presents the technical bases that th e Environmental Protection Agency (EPA or the Agency) has used for evaluating the risks from existing facilities and for determining that the prescribed work practice standa rds represent generally availabl e control technology (GACT), as required by section 112(d) of the 1990 amen dments to the Clean Air Act (CAA).

The Agency is also defining the scope of its re view of the Subpart W NESHAP to include the waste impoundments at in-situ leac h (ISL) uranium recovery facili ties and heap leach recovery operations, since all post-1989 impoundments, wh ich potentially contain uranium byproducts, are considered to be under the NESHAP. The Ag ency has defined the scope of the review to include regulation of the heap le ach pile, as it believes the p ile contains byproduct material during operations.

1.1 Introduction, History, and Basis

After a brief introduction, this report describes the events that led the Agency to promulgate a NESHAP for radon emissions from operati ng uranium mill tailings on December 15, 1989, in

Section 40 of the Code of Federal Regulations (40 CFR) Part 61, Subpart W. The 1977 amendments to the CAA include the requirement that the Administrator of EPA determines whether radionuclides should be regulated under the act. In December 1979, the Agency published its determination in the Federal Register (FR) that radionuclides constitute a hazardous air pollutant (HAP) with in the meaning of section 112(a)(1). In 1979, the Agency also developed a background information document (BID ) to characterize “sou rce categories” of

facilities that emit radionuclid es into ambient air, and in 1983, EPA proposed radionuclide NESHAPs for four source categories based on the results reported in a new BID. On September 24, 1986, the Agency issued a final NESHAP for operating uranium mill tailings, establishing an emission standard of 20 pico curies per square meter per second (pCi/(m 2 -sec)) for radon (Rn)-222 and a work practice standard re quiring that new tailings be disposed of in small impoundments or by continuous dis posal. Between 1984 and 1986, the Environmental Defense Fund (EDF), the Natural Resources Defe nse Council (NRDC), the Sierra Club (SC), and the American Mining Congress (AMC) filed various court petitions seeking modifications to the

NESHAPs.

In a separate decision, the U.S. District Court fo r the District of Columb ia outlined a two-step decision process that it would find acceptable, fi rst establishing a standard based solely on an acceptable level of risk, and then considering add itional factors, such as costs to establish the “ample margin of safety.”

Section 112(q)(1) of the 1990 CAA Amendments requires that cert ain emission standards shall be reviewed, and if appropriate, revised to co mply with the requireme nts of section 112(d). Subpart W is under review/revisi on in response to that require ment. Section 112(d) of the 1990 CAA Amendments lays out requirements for promulgating technology-based emissions standards for new and existing sources. In accord ance with section 112(d), the Administrator has2 elected to promulgate standards that provide fo r the use of GACT or management practices to regulate radon emissions from uranium recovery facility tailings impoundments noted in Subpart W.

1.2 The Uranium Extraction Industry Today

From 1960 to the mid-1980s, there was consider able uranium production in the states of Colorado, Nebraska, New Mexico, South Dakota, Texas, Utah, Wyoming, and Washington. In the early years, the uranium recovery industr y consisted of mines ( open pit and underground)

that were associated with conventional uran ium milling operations. Because of overproduction, the price of uranium rapidly declined in the 1980s. The declining uran ium market could not support the existing number of uranium recoveryoperations, and many of the uranium recovery facilities in the United States were closed, deco mmissioned, and reclaimed. In the mid- to late 1980s, several uranium recovery projects employi ng the solution, or ISL, mining process came on line. However, because of a need for clean energy, a need to develop domestic sources of energy, and other reasons, current forecasts predic t growth in the U.S. uranium recovery industry over the next decade and continuing into the future.

Conventional uranium mining and m illing facilities are one of two types of uranium recovery facilities that currently possess state or federal licen ses to operate. Representative of the extent of the conventional uranium milling operations that currently exist and are licensed in the United States are the mills at Sweetwater, Wyoming; Shootaring Canyon, Utah; and White Mesa, Utah. Only the White Mesa mill is currently in operation. A conventional mill at Piñon Ridge, Colorado, is currently in the planning and licensi ng stage. Additionally, a to tal of six potentially new conventional mill facilities are being discussed in New Mexico, Wyoming, Utah, and

Arizona.

The radon data for the conventional mill tail ings impoundments indicate that the radon exhalation rates from the surfaces are gene rally within the Subpart W standard of 20 pCi/(m 2 -sec), but occasionally the standard may be exceeded. When that occurs, the tailings are usually covered with more so il, and the radon flux is reduced.

Solution, or ISL, mining is defined as the leachin g or recovery of uranium from the host rock by chemicals, followed by recovery of uranium at the surface. ISL mining was first conducted in Wyoming in 1963. The research and development pr ojects and associated pilot projects in the 1980s demonstrated solution mining to be a vi able uranium recovery technique. Ten ISL facilities are currently operating (see Table 8, page 33), a nd about 23 other facilities are restarting, expanding, or pl anning for new operations.

Uranium is leached into solution through the injection into the ore body of a lixiviant. A lixiviant is a chemical solution used to selectively extr act (or leach) uranium from ore bodies where they are normally found underground. The inje ction of a lixiviant essentia lly reverses the geochemical

reactions that are associated with the uranium deposit. The lixiviant ensu res that the dissolved uranium, as well as other metals, remains in solu tion while it is collected from the mining zone by recovery wells.3 During typical solution mining, a por tion of the lixiviant is bled off in order to control the pressure gradient within the wellfield. The liquid bl ed from the lixiviant is sent to an evaporation pond, or impoundment. Since radium (Ra)-226 is pres ent in the liquid bled from the lixiviant, radon will be generated in and released from the ISL’s evaporation/holding ponds/ impoundments. The amount of radon released fro m these evaporation/holding ponds has been estimated and found to be small. (See Section 3.3.1.)

Heap leaching is a process by which chemicals are used to extract the economic element (for the purposes of Subpart W, uranium) from the ore. A large area of land is leveled with a small gradient, and a liner and collection system are inst alled. Ore is extracted fr om a nearby surface or underground mine and placed in heaps atop the liner. A leaching agent (usually an acid) will then be sprayed on the ore. As the leaching agent percolates through the heap, the uranium is

mobilized and enters the solution. The solution will flow to the bottom of the pile and then along the gradient into collecting pools, from which it w ill be pumped to an onsite processing plant. In the past, a few commercial heap leach facilities operated but none is now operating. Planning and engineering have been undertaken for two h eap leach facilities, one in Wyoming and the

other in New Mexico.

A brief review of Method 115, “Monito ring for Radon-222 Emissions” (40 CFR 61, Appendix B) (SC&A 2008), demonstrated that its use can still be considered current for monitoring radon flux from conventional uranium ta ilings impoundments. It is not an option for measuring radon emissions from evaporation or holding ponds because there is no solid surface on which to place the monitors.

1.3 Current Understanding of Radon Risk

A description of how the unders tanding of the risk presente d by radon and its progeny has evolved since the 1989 BID was published examines three parameters: (1) the radon progeny equilibrium fraction, (2) the epidemiological ri sk coefficients, and (3 ) the dosimetric risk coefficients. Additionally, SC&A (2011) used th e computer code CAP88 version 3.0 (Clean Air Act Assessment Package-1988) to analyze the ra don risk from eight operating uranium recovery sites, plus two generic sites.

The lifetime (i.e., 70-year) maxi mum individual risk (MIR) 1 calculated using data from eight actual uranium recovery sites was determined to be between 2.45×10 -5 to 2.59×10 -4 . The low end of the range is lower than the 3×10 -5 lifetime MIR reported in th e 1989 rulemaking for existing impoundments, while the high end of the ra nge is slightly higher than the 1.6×10 -4 lifetime MIR reported in the 1989 rulemaking for new impoundments. (SC&A 2011)

To protect public health, EPA strives to pr ovide the maximum feasible protection by limiting radon exposure to a lifetime MIR of appr oximately 1 in 10 thousand (i.e., 10 -4 ). Although the calculated high end of the lif etime MIR range is above 10 -4 , there are several mitigating factors. First, the highest MIR was calculated for a hypothe tical mill at an easter n generic site. If an

actual mill were to be located at the Eastern Gene ric site, it would be required to reduce its radon

1 In this BID all risks are presented as mortality risks. If it is desired to estimate the morbidity risk, simply multiply the mortality risk by 1.39.4 emissions as part of its licensing commitments. Also, the assumptions th at radon releases occur continuously for 70 years and that the same r easonably maximally exposed individual (RMEI) is exposed to those releases for the en tire 70 years are ve ry conservative.

Likewise, the risk assessment estimated that the ri sk to the population from all eight real uranium sites is between 0.0005 and 0.0009 fatal cancers pe r year, or approximately one case every 1,080 to 1,865 years to the 1.8 million persons living within 80 kilometers (km) of the sites. For the 1989 rulemaking, the estimated annual fatal cance r incidence to the 2 million people living within 80 km (50 miles) was 0.0043, which was le ss than one case every 200 years, for existing impoundments and 0.014, or approximately one cas e every 70 years, for new impoundments.

1.4 Evaluation of Subpart W Requirements

EPA has determined that radon releases from ur anium recovery facilities are HAPs, as defined by the CAA. Furthermore, no radionuclide (inc luding radon) releases have met the CAA’s definition of major sources, and thus radon re leases from uranium recovery facilities are classified as area sources. (See Section 5.3.) Under section 112(d) of the CAA, the EPA Administrator may elect to promulgate standards or requirements applicable to area sources that provide for the use of GACTs or management pr actices to reduce emissions of HAPs. For the four source categories of radon rel eases from uranium recovery facilities, the Administrator has elected to promulgate GACTs as follows:

Conventional Impoundments – Constructed on or before December 15, 1989

GACT The flux standard of 20 pCi/(m 2 -sec) contained in the current 40 CFR 61.252(a) will no longer be required; require th at these conventional impoundments be operated to meet one of two work pract ices: phased dispos al and continuous disposal, contained in th e current 40 CFR 61.252(b).

Conventional Impoundments – Constructed after December 15, 1989

GACT Retain the standard that conventional impoundment s be designed, constructed, and operated to meet one of two work practices: phased disp osal and continuous disposal, contained in th e current 40 CFR 61.252(b).

Nonconventional Impoundments – Where uranium byproduct ma terial (i.e., tailings) are contained in ponds and covered by liquids

GACT Retain the design and co nstruction requirements of 40 CFR 192.32(a)(1), with no size/area restrictions, and require that during the active life of the pond, at least 1 meter of liquid be maintained in the pond.5 Heap Leach Piles

GACT Retain the design and construction requirements of 40 CF R 192.32(a)(1), and require that the moisture content of the ope rating heap be maintained at or greater than 30 percent.

Additionally, the analyses provided in this BID support the following findings:

 Subpart W continues to be the appropri ate regulatory tool to implement the Administrator’s duty under the CAA fo r operating uranium mill tailings.

 By requiring that conventi onal impoundments be designed, constructed, and operated to meet one of two 40 CFR 61.252(b) work practices (i.e., phased disposal and continuous disposal), adoption of an emission limit (e.g., 20 pCi/(m 2 -sec)) is not necessary to protect public health.

 The requirement that conventional impound ments use either phased or continuous disposal technologies is appropr iate to ensure that public he alth is protected with an ample margin of safety, and is consis tent with section 112(d) of the 1990 CAA Amendments that require standards based on GACT.

 The standard should be clarified to ensure that all owners and operators of uranium recovery facilities (conventional mills, ISL, and heap leach) are aware that all of the structures/facilities they em ploy to manage uranium byproduct material (i.e., tailings) are regulated under Subpart W.

1.5 Economic Impacts

The economic impact analysis to support any po tential revision of the Subpart W NESHAP is presented in four distinct areas:

(1) A review and summary of the original 1989 economic assessment and supporting documents are provided.

(2) The baseline economic costs for development of new conventional mills, ISL facilities, and heap leach facilities ar e developed and presented.

(3) The anticipated costs to the industries versus the environmental and publ ic health benefits to be derived from each of the four proposed GACTs are discussed.

(4) Finally, information is provided on the econom ic impacts to disadva ntaged and tribal populations and on envi ronmental justice.

The baseline costs were estimated using recently published cost data for actual uranium recovery facilities. For conventional mills, data from th e proposed new mill at the Piñon Ridge project in Colorado were used. Data from two proposed ne w ISL facilities were used; the first was the Centennial Uranium project in Colorado and the second was the Dewey-Burdock project in South Dakota. The Centennial project is expe cted to have a 14 to 15-year production period,6 which is a long duration for an ISL facility, while the Dewey-Bu rdock project is expected to have a shorter production period of about 9 years, wh ich is more representative of ISL facilities. For the heap leach facility, data from the Sheep Mountain project in Wyoming were used. Table 1 summarizes the unit cost (dollars per pound) estimat es for all four uraniu m recovery facilities. As shown, on a unit cost basis, heap leach facilitie s are projected to be the least expensive, and the two ISL facilities the most expensive.

Table 1: U 3 O 8 Market Value and Cost to Produce (Nondiscounted)

Average U 3 O 8 Price ($/lb) $65.00

Average U 3 O 8 Cost ($/lb) w/ LoC w/o LoC

Conventional $51.56 $47.24
ISL (Long) $53.89 $51.81
ISL (Short) $52.49 $51.46
Heap Leach $46.08 $42.87

Because the four proposed GACTs are not expected to change the manner in which any of the uranium recovery facilities are designed, built, or operated, no additional economic benefits or costs are associated with the proposed Subpart W revisions.

At 10 of the 15 existing or proposed uranium rec overy sites analyzed, the percentage of Native Americans in the population exceeds the national nor m, while at nine sites, the percentage of Native Americans in the population exceeds the regional norm. At 11 of the 15 sites, the percentage of the population that is white exceed s both the national and regional norms. Finally, the percentage of the population at all uranium recovery sites that is either African-American or Other is less than the national norm, while the percentage of African-Ame ricans and Others is less than the regional norm at all but one site. The analysis found th at uranium recovery facilities are located in areas that are very poor (i.e., ranked in the lowest 0.6% in the country) to areas that are more economically advantaged (i.e., ranked in the 91.2 percentile). Si x of the 15 sites are located in areas that have per capita nonfarm wealth that is above the United States’ 50 th
percentile. On the other hand, five sites are located in areas wh ere the per capita nonfarm wealth is below the country’s 10 th percentile.

2.0 INTRODUCTION, HISTORY, AND BASIS

On December 15, 1989, EPA promulgated a NESHAP for radon emissions from operating uranium mill tailings (40 CFR 61, Subpart W). Sec tion 112(q) of the CAA, as amended, requires EPA to review, and if appropriate, revise or update the Subpart W standard on a timely basis (within 10 years of passage of the CAA Amendments of 19 90). Soon after the original promulgation of the standard, the uranium industr y in the United States declined dramatically. However, recent developments in the market for uranium have led to some companies expressing their intention to pursue licensing of new facilities, and therefore, EPA is reviewing the necessity and adequacy of the Subpart W regulations before these proposed faciliti es become operational.7 Two separate standards are defined in Subpart W. The first states that existing sources (facilities constructed before December 15, 1989) must ensure that emissions to the ambient air from an existing uranium mill tailings pile shall not exceed 20 pCi/(m 2 -sec) or 1.9 picocuries per square foot per second (pCi/(ft 2 -sec)) of Rn-222. To demonstrate compliance with this emission standard, facilities are require d to monitor emissions in acco rdance with Method 115 of 40 CFR 61, Appendix B, and file an annual report with EPA showing the results of the compliance monitoring. The second Subpart W standard pres cribes that for new sources (facilities constructed on or after December 15, 1989), no ne w tailings impoundment can be built unless it is designed, constructed, and operated to meet one of the two following work practices:

(1) Phased disposal in lined tailings impoundments that are no more than 40 acres in area and meet the requirements of 40 CFR 192.32(a) as determined by the U.S. Nuclear Regulatory Co mmission (NRC). The owner or operator shall have no more than two impoundments, incl uding existing impoundments, in operation at any one time.

(2) Continuous disposal of tailings such th at tailings are dewa tered and immediately disposed of with no more than 10 acre s uncovered at any time and operated in accordance with 40 CFR 192.32(a) as determined by the NRC.

The work practice standard also applies to op erations at existing sources, once their existing impoundments can no longer accept additional tailings.

The facilities covered by Subpart W are uranium recovery facilities, also licensed and regulated by the NRC or its Agreement States. The N RC becomes involved in uranium recovery operations once the ore is processed and chemically altered. This occurs either in a uranium mill (the next step from a conventional mine) or dur ing ISL or heap leach. For this reason, the NRC regulates ISL facilities, as well as uranium mills and the disposal of liquid and solid wastes from uranium recovery operations (including mill taili ngs), but does not regulate the conventional uranium mining process. The NRC regulations for the protection of the public and workers from exposure to radioactive materi als are found in 10 CFR 20, while specific requirements for the design and operation of uranium mills and di sposition of tailings are found in 10 CFR 40, Appendix A.

2.1 Document Contents and Structure

This report is divided into six sections. The fi rst two sections are the Executive Summary and this introduction, which includes discussions of the history of the development of Subpart W (Section 2.2) and the basis for the 1989 risk asse ssments (Section 2.3). Four technical sections,

the contents of which are summarized belo w, follow this in troductory section.

2.1.1 The Uranium Extraction Industry Today

After a brief history of the uranium market, S ection 3.0 identifies both the uranium recovery facilities that are licensed today and those that have been proposed to be built in the future.

For currently existing impoundments, Section 3.0 presents the following information:8  Data on the configuration of current impoundments.

 Results of compliance monitoring.

Section 3.0 also presents a description of the Method 115 radon monitoring method.

2.1.2 Current Understanding of Radon Risk

Section 4.0 presents a qualitative analysis of the change s that have occurred in the understanding

of the risks associated with Rn-222 releases from impoundments. Emphasis is on the changes to the predicted radon progeny equilibrium fracti ons and the epidemiological and dosimetric lifetime fatal cancer risk per wo rking level (WL). Section 4.0 al so discusses how the current analytical computer model, CAP88 Version 3.0, e volved from and differs from the models used for the 1989 risk assessment (i.e., AIR DOS-EPA, RADRISK, and DARTAB). Finally, Section 4.4 presents dose and risk estimates for several current uranium recovery facilities.

2.1.3 Evaluation of Subpart W

The evaluation of Subpart W requirements required th e analyses of some key issues to determine if the current technology has a dvanced since the 1989 promulgation of the rule. The key issues include: existing and proposed uranium recovery facilities, Resource Conservation and Recovery Act (RCRA) comparison, regulatory history, tailings impoundment technologies, radon measurement methods, and risk assessment. Secti on 5.0 discusses these key issues, in order to determine whether the requirements of S ubpart W are necessary and sufficient.

Based on the evaluation of the ke y issues and in keeping with section 112(d) of the CAA, Section 5.0 also presents GACT ra don emission control standards fo r three categories of uranium recovery facilities:

(1) Conventional impoundments.

(2) Nonconventional impoundments, where uraniu m byproduct material (i.e., tailings) is contained in ponds and covered by liquids.

(3) Heap leach piles.

In addition to the key issues, several issues that need clarification in order to be more fully understood are presented and described. The issues in need of clarification include extending monitoring requirements, defining when the clos ure period for an operating facility begins, interpretation of the term “s tandby,” the role of weather ev ents, and monitoring reporting requirements.

2.1.4 Economic Impact Analysis

Section 6.0 of the document reviews and reassesse s all the additional econo mic impacts that may

occur due to the extension and revision of the Subpart W NESHAP and specifically addresses the following:9  A review and summary of the original 1989 economic assessment and supporting documents are provided.

 The baseline economic costs for the developm ent of new conventional mills and ISL and heap leach facilities are developed and presented.

 The anticipated costs to industries versus envi ronmental and public health benefits to be derived from each of the four proposed GACTs are discussed.

 Finally, information is provided relati ng to economic impacts on disadvantaged populations and tribal populations and to environmental justice.

2.2 History of the Developmen t of the Subpart W NESHAP

The following subsections present a brief history of the developm ent of environmental radiation protection standards by EPA, with particular emphasis on the development of radionuclide

NESHAPs.

Table 2 presents a partial time line sequence of EPA’s radiation standards with emphasis on the NESHAPs, including Subpart W.

Table 2: Partial Timeline of EPA’s Radiation Standards

January 13, 1977 EPA publishes 40 CFR 190 – Environmental Protection Standards for Nuclear Power Operations. August 1979 EPA publishes first BID, Radiological Impacts Caused by Emission of Radionuclides into

Air in the United States , EPA 520/7-79-006. December 27, 1979 EPA determines ra dionuclides constitute a HAP – (sec tion 112(a)(1) amendments to the

CAA. January 5, 1983 EPA under UMTRCA promulgates, 40 CFR 192, Subpart B “Standards for Cleanup of Land and Buildings Contaminated with Re sidual Radioactive Materials from Inactive Uranium Processing Sites,” that for inactive ta ilings or after closure of active tailings, the

radon flux should not exceed an average release rate of 20 pCi/(m 2 -sec). March 1983 EPA publishes draft report, Background Information Document Proposed Standards for

Radionuclides , EPA 520/1-83-001, and proposes radionuclide NESHAPs for:

1. DOE and Non-NRC-Licensed Federal Facilities.

2. NRC-Licensed Facilities.

3. Elemental Phosphorus Plants.

4. Underground Uranium Mines. September 30, 1983 EPA issues standards under UM TRCA (40 CFR 192, Subparts D and E) for the management of tailings at locations licensed by the NRC or the States under Title II of the UMTRCA. These standards do not specifically limit Rn-222 emissions until after closure of a facility; however, they require ALARA procedures for Rn-222 control. February 17, 1984 SC sues EPA (District Court for Northern California) and demands EPA promulgate final NESHAP rules for radionuclides or find that they do not constitute a HAP (i.e., “de-list”" the pollutant). In August 1984, the court grants the SC motion and orders EPA to take final actions on radionuclides by October 23, 1984. October 22, 1984 EPA issues Final Background Information Document Proposed Standards for

Radionuclides , EPA 520/1-84-022-1and -2. October 23, 1984 EPA withdraws the proposed NESHAP s for elemental phosphorus plants, DOE facilities,

and NRC-licensed facilities.10 Table 2: Partial Timeline of EPA’s Radiation Standards

December 1984 District Court finds EP A in contempt. EPA and SC submit motion to court with schedule (August 5, 1985). Court orders EPA to issue final standards for Rn-222 emissions from licensed uranium mills and mill tailings impoundments by May 1, 1986 (later moved to August 15, 1986). February 6, 1985, to September 24, 1986 EPA promulgates NESHAPs for:

1. DOE Facilities (February 1985).

2. NRC-Licensed Facilities and Non-DOE Federal Facilities (February 1985).

3. Elemental Phosphorus Plants (February 1985).

4. On April 17, 1985, Rn-222 emissions from underground uranium mines added.

5. On September 24, 1986, Rn-222 from licensed uranium mill tailings added – 20 pCi/(m 2 -sec) and the work practice standa rd for small impoundments or continuous disposal. November 1986 AMC and EDF file petitions challe nging the NESHAPs for operating uranium mills. July 28, 1987 The Court of Appeals for the District of Columbia remanded to EPA the NESHAP for vinyl chloride (see text). Given the decision, EPA petitioned the court for a voluntary remand of standards and asked that the pending litigation on all issues relating to its radionuclide NESHAPs be placed in abeyance du ring the rulemaking. EPA also agreed to reexamine all issues raised by parties to th e litigation. The court granted EPA’s petition on December 8, 1987. September 14, 1989 EPA promulgates NESHAPs for benzene, etc. Importantly, EPA establishes the “fuzzy bright line.” That is, EPA’s approach to resi dual risk under section 112 (as advanced in the Hazardous Organic NESHAPs and approved by the District of Columbia Circuit in

NRDC v. EPA ) as essentially establishing a “fuzzy bright line” with respect to carcinogens, whereby EPA must eliminate risks above one hundred in one million (1 in 10,000) , does not have to address risks below one in one million (1 in 1,000,000), and has discretion to set a residual risk standard somewhere in between (Jackson 2009). In a second step, EPA can consid er whether providing the public with “an ample margin of safety” requires risks to be reduced further than this “safe” level, based on EPA’s

consideration of health information and othe r factors such as cost, economic impact, and technological feasibility (Jackson 2009). September 1989 EPA publishes the NESHAPs for radionuclides. The agency prepared an EIS in support of the rulemaking. The EIS consisted of three volumes: Volume I, Risk Assessment Methodology ; Volume II, Risk Assessments ; and Volume III, Economic Assessment. December 15, 1989 EPA promulgates NESHAPs for:

 Subpart B: National Emission Standards for Radon Emissions from Underground

Uranium Mines.

 Subpart H: Emissions of Radionuclides Other than Radon from DOE Facilities.

 Subpart I: National Emissions of Radionuclides Other than Radon from DOE Facilities by NRC and Federal Fac ilities Not Covered by Subpart H.

 Subpart K: Radionuclide Emissions from Elemental Phosphorus Plants.

 Subpart Q: Radon Emissions from DOE Facilities.

 Subpart R: Radon Emissions from Phosphogypsum Stacks.

 Subpart T: Radon Emissions from the Disposal of Uranium Mill Tailings. (rescinded effective June 29, 1994; published in the FR July 15, 1994).

 Subpart W: Radon Emissions from Operating Uranium Mill Tailings Piles. November 15, 1990 President signs the CAA Amendments of 1990. Part of the act requires that some regulations passed before 1990 be reviewed and, if appropriate, revised within 10 years of

the date of enactment of the CAA Amendments of 1990. The amendments also instituted a technology-based framework for HAPs. Sources that are defined as large emitters are to employ MACT, while sources that emit lesser quantities may be controlled using GACT.11 2.2.1 The 1977 Amendments to the Clean Air Act

On January 13, 1977 (FR 1977), EPA established envi ronmental protection standards for nuclear power operations pursuant to its authority under the Atomic Ener gy Act (AEA). The standards in 40 CFR 190, which covered all licensed facilities that are part of the uranium fuel cycle, established an annual limit on exposure to memb ers of the public. The NRC or its Agreement States, which licenses these facili ties, has the responsibility for the enforcement of the Part 190 standards. Additionally, the NRC imposes the requ irement that licensees keep all exposures “as low as reasonably achievable” (ALARA). The Part 190 standards exempted Rn-222 from the

annual limit because of the uncertainties asso ciated with the risk of inhaled radon.

After the promulgation of 40 CF R 190, the 1977 amendments to the CAA were passed. These amendments included the requirement that th e Administrator of EPA determine whether radionuclides should be regulated under the CAA.

In December 1979, the Agency published its determination in the Federal Register (FR 1979)

that radionuclides constitute a HAP within the meaning of section 112(a)(1). As stated in the FR,

radionuclides are known to cause can cer and genetic defects and to contribute to air pollution that may be anticipated to result in an incr ease in mortalities or an increase in serious, irreversible, or incapacitating reversible illnesses. The Agency further determined that the risks posed by emissions of radionucli des into the ambient air wa rranted regulation and listed

radionuclides as a HAP under section 112.

Section 112(b)(1)(B) of the CAA requires the Admi nistrator to establish NESHAPs at a “level which (in the judgment of the Admi nistrator) provides an ample marg in of safety to protect the public health” or find that they ar e not hazardous and delist them.

2.2.2 Regulatory Activities between 1979 and 1987

To support the development of radionuclide NESHAPs, the Agency developed a BID to characterize “source categories” of facilities that emit radionuclid es into ambient air (EPA 1979). For each source category, EPA developed informati on needed to characterize the exposure of the public. This included characterizat ion of the facilities in the so urce category (numbers, locations, proximity of nearby individuals); radiological source terms (curie s/year (Ci/yr)) by radionuclide, solubility class, and particle si ze; release point data (stack he ight, volumetric flow, area size); and effluent controls (type, efficiency). Doses to nearby in dividuals and regional populations caused by releases from either actual or model facilities were estimated using computer codes (see Section 2.3).

In 1983, EPA proposed radionuclide NESHAPs for f our source categories based on the results reported in a new BID (EPA 1983). These four so urce categories were the Department of Energy (DOE) and non-NRC-licensed federal facilities, NRC-licensed facilities, elemental phosphorus plants, and underground uranium mi nes. For all other source categ ories considered in the BID (i.e., coal-fired boilers, the phosphate industry and other extraction industrie s, uranium fuel-cycle facilities, uranium mill tailings, high-level wa ste disposal, and low-energy accelerators), the Agency found that NESHAPs were not necessary. In reaching this conclusion, the Agency found

that either the levels of ra dionuclide emissions did not cause a significant dose to nearby12 individuals or the regional populatio ns, the additional effluent controls were not cost effective, or the existing regulations under other authorities were sufficient to keep emissions at an acceptable

level.

During the public comment period on the proposed NESHAPs, the Agency completed its rulemaking efforts under the Uranium Mill Tailings Remedial Control Act (UMTRCA) to establish standards (40 CFR 192) for the disposal of uranium m ill tailings. With respect to the emission of Rn-222, the UMTRCA standards estab lished a design standard calling for an Rn-222 flux rate of no more than 20 pCi/(m 2 -sec).

In February 1984, the SC sued EPA in the U.S. District Court for Northern California ( Sierra

Club v. Ruckelshaus , No. 84-0656) (EPA 1989), demanding that the Agency promulgate final

NESHAPs or delist radionuclides as a HAP. The court sided with the plaintiffs and ordered EPA to promulgate final regulations. In October 1984, EPA withdrew the proposed NESHAPs for elemental phosphorus plants, DOE facilities, an d NRC-licensed facilities, finding that existing control practices protected the publ ic health with an ample margin of safety (FR 1984). EPA also

withdrew the NESHAP fo r underground uranium mines, but stated its intention to promulgate a different standard and publishe d an Advance Notice of Proposed Rulemaking (ANPR) to solicit

additional information on control methods. It also published an ANPR for licensed uranium mills. Finally, the FR notice affirmed the decisi on not to regulate the other source categories identified in the proposed rule, with the ex ception that EPA was doing further studies of phosphogypsum stacks to see if a standard was needed.

In December 1984, the U.S. District Court for Northern California found EPA’s action of withdrawing the NESHAPs to be in contempt of the court’s order. Given the ruling, the Agency issued the final BID (EPA 1984) and promulga ted final standards for elemental phosphorus plants, DOE facilities, and NRC-licensed facil ities in February 1985 (FR 1985a), and a work practice standard for underground uranium mine s in April of the same year (FR 1985b).

The EDF, the NRDC, and the SC filed court petitions seeking review of th e October 1984 final decision not to regulate the source categories identified abov e, the February 1985 NESHAPs, and the April 1985 NESHAP. The AMC also filed a petition seeking judi cial review of the NESHAP for underground uranium mines.

On September 24, 1986, the Agency issued a fina l NESHAP for operating uranium mill tailings (FR September 24, 1986), which establishe d an emission standard of 20 pCi/(m 2 -sec) for Rn-222 and a work practice standard requiring that new tailings be disposed of in small impoundments or by continuous disposal. One justifications for the work practices was that, while large impoundments did not pose an unacc eptable risk during ac tive operations, the cyclical nature of the uranium milling industry could lead to prolon ged periods of plant standby and the risk that the tailings impoundments could experience signif icant drying, with a resulting increase in Rn-222 emissions. Furthermore, the Agency believed that the two acceptable work practices actually saved the industry from the signifi cant costs of construc ting and closing large impoundments before they were completely fill ed. With the promulgati on of the NESHAP for operating uranium mill tailings, three EPA regulations covered the releases of radionuclides into13 the air during operations and tailings disposal at uranium mills: 40 CFR 190; 40 CFR 192; and 40 CFR 61, Subpart W.

In November 1986, the AMC and the EDF filed pe titions challenging th e NESHAP for operating uranium mill tailings.

2.2.3 Regulatory Activities between 1987 and 1989

While the petitions filed by the ED F, NRDC, SC, and AMC were stil l before the courts, the U.S. District Court for the District of Columbia, in NRDC v. EPA (FR 1989b), found that the Administrator had impermissibly considered cost s and technological feasibility in promulgating the NESHAP for vinyl chloride. The court outlined a two-step decision process that it would find acceptable, first establishing a standard based so lely on an acceptable level of risk and then considering additional factors, such as costs, to establish the “amp le margin of safety.” Given the court’s decision, the Agency reviewed how it ha d conducted all of its NESHAP rulemakings and requested that the court grant it a voluntary remand for its radionucli de NESHAPs. As part of an agreement with the court and the NRDC, the Agency agreed to reconsider all issues that were currently being litigated, and it agreed that it would explicitly consider the need for a NESHAP for two additional source categories: ra don from phosphogypsum stacks and radon from DOE facilities. The subsequent reconsiderati on became known as the radionuclide NESHAPs reconsideration rulemaking.

2.2.4 1989 Radionuclide NESHAPs Reconsideration Rulemaking

In the radionuclide NESHAPs rec onsideration rulemaking, the Admini strator relied on a “bright line” approach for determining whether a source category required a NESHAP. This meant that no NESHAP was required if all individuals expo sed to the radionuclide emissions from the facilities in the source category were at a lifetime cancer risk of less than 1 in 1,000,000, and less than 1 fatal cancer per year was estimated to be incurred in the population. For source categories that did not meet this “bright line” exclusi on, the Agency adopted a two-step, multi-factor approach to setting the emission standards.

The first step established a presumptively accepta ble emissions level corresponding to an MIR of about 1 in 10,000 lifetime cancer ris k, with the vast majority of e xposed individuals at a lifetime risk lower than 1 in 1,000,000, and with less than 1 total fatal can cer per year in the exposed population. If the baseline emissions from a s ource category met these criteria, they were presumed adequately safe. If they did not m eet these criteria, then the Administrator was compelled by his nondiscretionary duty to determ ine an emission limit that would correspond to risks that were adequately safe.

After baseline emissions were determined to be ade quately safe or an adequately safe alternative limit defined, the analysis moved to the second st ep, where reduced risks for alternative emission limits were evaluated, along with the technological feasibility and cost s estimated to be associated with reaching lower levels. In the tw o-step approach, the Administrator retained the

discretion to decide whether the NESHAP should be set at these lower limits.14 2.2.5 1990 Amendments to the Clean Air Act

NESHAP Subpart W is under consideration for re vision because section 112(q)(1) requires that

certain emission standards in effect before th e date of enactment of the 1990 CAA Amendments shall be reviewed and, if appropriate, revised to comply with the requirements of section 112(d). As stated previously, soon after the original promulgation of th e standard, the uranium industry in the United States declined dramatically, ne gating the need to perform the Subpart W review. However, as discussed in Section 3.1, recent developments in the market for uranium have led to forecasts of growth in the uranium market over the next decade and continuing for the foreseeable future. Therefore, EPA is reviewi ng the necessity and adequacy of the Subpart W regulations at this time, before facilities developed in respon se to those forecasts become operational.

Section 112(d) of the 1990 CAA Amendments lays out requirements for promulgating technology-based emissions standards for ne w and existing sources. Section 112(c) lists radionuclides, including radon, as an HAP, while section 112(a) define s two types of HAP sources: major sources and area sources. Depending on whether the source is a major or area source, section 112(d) prescrib es standards for the regulation of emissions of HAPs.

The regulation of HAPs at major sources is di ctated by the use of ma ximum achievable control technology (MACT). Section 112(d ) defines MACT as the maximum degree of reduction in

HAP emissions that the Administrator determin es is achievable, considering the cost of achieving the reduction and any non-air-quality h ealth and environmental impacts and energy requirements. With respect to ar ea sources, section 112(d )(5) states that, in lieu of promulgating an MACT standard, the Administra tor may elect to promulgate sta ndards that provide for the use of GACT or management prac tices to reduce HAP emissions.

EPA has determined that radon emissions from ur anium recovery facility tailings impoundments are an area source and that GACT applies (see Sec tion 5.3). The Senate re port on the legislation (U.S. Senate 1989) contains additional in formation on GACT and describes GACT as:

...methods, practices and t echniques which are commercially available and appropriate for application by the sources in the category considering economic impacts and the technical c apabilities of the forms to operate and maintain the emissions control systems.

Determining what constitutes a GACT involve s considering the cont rol technologies and management practices that are ge nerally available to the area sources in the source category. It is also necessary to consider the st andards applicable to major sources in the same industrial sector to determine if the control technologies and mana gement practices are tran sferable and generally available to area sources. In appropriate circum stances, technologies and practices at area and major sources in similar categories are considered to determine whether such technologies and practices could be generally available for the ar ea source category at i ssue. Finally, as noted above, in determining GACTs for a particular area source category, the costs and economic impacts of available control technologies a nd management practices on that category are

considered.15 2.3 Basis for the Subpart W 1989 Risk Assessment and Results

In the 1989 NESHAP for operating uranium mill ta ilings, exposures and risks were estimated using a combination of actual site data for ex isting impoundments and model or representative facilities for future impoundments and computer models. The 1989 risk assessment reflected the estimated risks to the regional (0-80 km [0- 50 mile]) populations associated with the 11 conventional mills that were operating or in standby 2 at that time. Mathematical models were developed to simulate the transport of radon re leased from the mill tailings impoundments and the exposures and risks to individuals and popula tions living near the mills. Those models were programmed into three computer programs for the 1989 risk assessment: AIRDOS-EPA, RADRISK, and DARTAB. The paragraphs that fo llow briefly discuss each of these computer

programs.

AIRDOS-EPA was used to calculate radionuclide con centrations in the air, rates of deposition on the ground, concentrations on th e ground, and the amounts of radionuclides taken into the body

via the inhalation of air and i ngestion of meat, milk, and vege tables. A Gaussian plume model was used to predict the atmospheric dispersion of radionuclides released from multiple stacks or

area sources. The amounts of radionuclides that ar e inhaled were calculated from the predicted

air concentrations and a user-s pecified breathing rate. The amount s of radionuclides in the meat, milk, and vegetables that people ingest were calculated by coupling th e atmospheric transport models with models that pr edict the concentration in the terrestrial food chain.

RADRISK computed dose rates to or gans resulting from a given qua ntity of radionuclide that is ingested or inhaled. Those dose rates were then used to calculate the risk of fatal cancers in an exposed cohort of 100,000 persons. All persons in the cohort were assumed to be born at the same time and to be at risk of dying from competing causes (including natural background radiation). RADRISK tabulated es timates of potential health ri sk due to exposure to a known quantity of approximately 500 different radionuclid es and stored these estimates until needed.

These risks were summarized in terms of the probability of premature death for a member of the cohort due to a given quantity of each radi onuclide that is inge sted or inhaled.

DARTAB provided estimates of the impact of radi onuclide emissions from a specific facility by combining the information on the amounts of radi onuclides that were inge sted or inhaled (as provided by AIRDOS-EPA) with dosimetric and health effects data for a gi ven quantity of each radionuclide (as provided by RADRISK). The DA RTAB code calculated dose and risk for

individuals at user-selected lo cations and for the population with in an 80-km radius of the

source. Radiation doses and risks could be broken down by radionuclide, exposure pathway, and

organ.

Of the 11 conventional mills that were operating or in standby at that time, seven had unlined impoundments (the impoundments were clay lined, but not equipped with synthetic liners), while five had impoundments with synthetic liners. As the NESHAP revoked the exemption to the liner requirement of 40 CFR 192.32(a), the mills with unlined impoundments had to close the

2 “Standby” means the period of time when a fac ility may not be accepting new tailings but has not yet entered closure operations.16 impoundments and move towards final reclamation and long-term stabilization of the tailings impoundments.

2.3.1 Existing Impoundments

The NESHAP for operating uranium mill tailings addressed both existing and future tailings impoundments. For the existing impoundments, th e radon emissions and estimated risks were developed using site-specific data for each of the 11 mills that were operating or in standby at the

time the assessment was made. These data included the average Ra-226 content of the tailings, the overall dimensions and areas of the impoundme nts (developed from licensing data and aerial photographs), areas of dry (unsaturated) tailings , the existing populations within 5 km of the centers of the impoundments (identified by fiel d enumeration), 5–80 km populations derived from U.S. Census tract data, meteorological da ta (joint frequency di stributions) from nearby weather stations, mixing heights, and annual precipitation rates.

The AIRDOS-EPA code was used to estimate air borne concentrations based on the calculated

Rn-222 source term for each facil ity. Rn-222 source terms were estimated on the assumption that an Rn-222 flux of 1 pCi/(m 2 -sec) results for each 1 picocurie per gram (pCi/g) of Ra-226 in the tailings and the areas of dr ied tailings at each site. The radon flux rate of 1 pCi/(m 2 -sec) per pCi/g Ra-226 was derived based on theoretica l radon diffusion equations and on the lack of

available radon emissions measurements.

For each sector in the 0–80 km grid around each facility, the estimated Rn-222 airborne concentration was converted to cumulative working level months (WLMs), assuming a 0.50 equilibrium fraction between radon and its decay products, an aver age respiration rate appropriate for members of the general public, an d the assumption of continuous exposure over a 70-year lifetime. Using a risk coefficient of 760 fatalities/10 6 WLM, lifetime risk, fatal cancers per year, and the risk distribution were calculated for the exposed population.

The baseline risk assessment for existing uranium tailings showed an MIR of 3×10 -5 which was below the benchmark level of approximately 1×10 -4 and is, therefore, presumptively safe. Additionally, the risk assessment calculated 0.0043 annual fatal cancers in the 2 million persons living within 80 km of the mills. The distribution of the cancer risk showed that 240 persons

were at risks between 1×10 -5 and 1×10 -4 , and 60,000 were at risks between 1×10 -6 and 1×10 -5

. The remainder of the population of about 2 million was at a risk of less than 1×10 -6 . Based on these findings, EPA concluded that baseline risks were acceptable.

The decision on an ample margin of safety consid ered all of the risk da ta presented above plus costs, scientific uncertainty, and the technical fe asibility of control tec hnology necessary to lower emissions from operating uranium mill tailings pile s. As the risks from existing emissions were very low, EPA determined that an emission standard of 20 pCi/(m 2 -sec), which represented current emissions, was all that was necessary to provide an ample margin of safety. The necessity for the standard was explained by the ne ed to ensure that mills continued the current control practice of keeping taili ngs wet and/or covered. Finally, to ensure that ground water was not adversely affected by continued operation of ex isting piles that were not synthetically lined17 or clay lined, the NESHAP ended the exemption to the requirements of 40 CFR 192.32(a), which protects water supplies from contamination.

2.3.2 New Impoundments

The 1989 risk assessment for new mill tailings impoundments was based on a set of model mills, defined so that the impact of alternative dispos al strategies could be evaluated. For the purpose of estimating the risks, the model mills were ch aracterized to reflect operating mills, and the dispersion modeling and population exposures were based on the arid conditions and sparse population density that charac terize existing impoundments in the southwestern states.

For new impoundments, a baseline consisting of one large impoundment (116 acres, which is 80% wet or ponded during its 15-ye ar active life) was modeled (i .e., the continuation of the current practice). The baseline re sults indicated an MIR of 1.6×10 -4 , a fatal cancer incidence of 0.014 per year, and only 20 persons at a risk greater than 1×10 -4 . Given the numerous uncertainties in establishing the parameters fo r the risk assessment and in modeling actual emissions and exposures, the Administrator found th at the baseline emissions for new tailings impoundments met the criteria for presumptively safe.

The decision on an ample margin of safety for ne w tailings considered two alternatives to the baseline of one large impoundment: phased dis posal using a series of small impoundments and continuous disposal. The evaluati on of these alternatives showed a modest reduction in the MIR and the number of fatal cancers per year, but a si gnificant increase in the number of individuals

at a lifetime risk of less than 1×10 -6 . The costs estimated for the two alternatives showed that phased disposal would lead to an incremental cost of $6.3 million, while continuous disposal was believed to actually result in a modest cost saving of $1 million.

Given the large uncertainties associated with th e risk and economic assessments performed for the new tailings impoundments, and considering the boom and bust cycles that the uranium industry has experienced, EPA determined that a work practice standard was necessary to prevent the risks from increasing if an impound ment were allowed to become dry. Finally, although continuous disposal showed slightly lowe r overall risks and costs than phased disposal, the Administrator recognized that it was not a proven technology for disposal of uranium mills tailings. Therefore, he determined that the work practice standard should allow for either phased disposal (limited to 40-acre impoundments, with a maximum of two impoundments open at any one time) or continuous disposal.

3.0 THE URANIUM EXTRACTION INDUSTRY TODAY: A SUMMARY OF THE

EXISTING AND PLANNED URANIUM RECOVERY PROJECTS

Section 3.1 describes the historic al uranium market in the Unite d States. In the 1950s and 1960s, the market was dominated by the U.S. government’s need for uranium, after which the commercial nuclear power industry began to control the market. The next three sections describe the types of process facilities that were and cont inue to be used to recover uranium. Section 3.2 describes conventional mills and includes descriptions of several existing mines, while

Section 3.3 describes ISL facilitie s. Heap leach facilities are described in Section 3.4. Finally,18 Section 3.5 discusses the appli cability of the Subpart W recommended radon flux monitoring

method.

3.1 The Uranium Market

The uranium recovery industry in the United States is primarily located in the arid southwest. From 1960 to the mid 1980s, there was consider able uranium production in the states of Colorado, Nebraska, New Mexico, South Dakota, Texas, Utah, Wyoming, and Washington. The majority of the uranium production at that time was associated with defense needs, while a lesser amount was associated with commercial power reactor needs. Without exception, the uranium recovery industry consisted of mines (open pi t and underground) that were associated with conventional uranium milling operations. The co nventional uranium mining/milling process is

described in Section 3.2.

When the demand for uranium could not support the existing number of uranium recovery operations, there was a movement to decommissi on and reclaim much of the uranium recovery industry in the United States.

The UMTRCA Title I program established a join t federal/state-funded program for remedial action at abandoned mill tailings sites where tailings resulted largely from production of uranium for the weapons program. Now there is Federal ow nership of the tailings disposal sites under general license from the Nuclear Regulatory Co mmission (NRC). Under Titl e I, the Department of Energy (DOE) is responsible for cleanup and remediation of these abandoned sites. The NRC is required to evaluate DOE’s design and implementation and, after remediation, concur that the sites meet standards set by EPA.

The UMTRCA Title II program is directed towa rd uranium mill sites licensed by the NRC or Agreement States in or after 1978. Title II of the act provides –

 NRC authority to control radiol ogical and nonradiological hazards.

 EPA authority to set generally applicab le standards for bot h radiological and nonradiological hazards.

 Eventual state or federal ownership of the disposal sites, under general license from

NRC. 3

In the mid- to late 1980s, several commercial uranium recovery projects employing the solution, or ISL, mining process came on line. Section 3.3 describes the uranium ISL mining process. The uranium ISL projects and the data that they co llected served as the industry standard. This industry saw an increase in activity as the conve ntional mine/milling operations were being shut

down.

This shift in the method of uranium mining was a ssociated with economic conditions that existed at the time. The price of uranium rapidly dec lined in the 1980s. The decline in price was associated with overproduction that took place du ring the earlier years. The peak in production was associated with Cold War production and asso ciated contracts with DOE. However, as the

3 http://www.nrc.gov/reading-rm/doc-co llections/fact-sheets/mill-tailings.html19 Cold War came to an end, the need for uranium began to diminish. The amount of uranium that was needed for DOE projects was greatly diminish ed and, therefore, the price of uranium saw a decline. Figure 1 shows the spot prices for natural uranium. Note the price decline in the early

1980s.

Figure 1: Historical Uranium Prices

Additionally, inexpensiv e uranium appeared on the worldwid e market associated with the foreign supplies of low-grade and rather impur e yellowcake. Only minimal purification and associated refinement was necessary to pr oduce a yellowcake feedstock that could supply

domestic and worldwide uranium needs from the low-grade foreign supply. Finally, the megatons to megawatts downblending program also supplied large supplies of uranium, both domestically and worldwide. Classical supply and demand economic principles established a market that had oversupply, constant demand and, therefore, a declining pr ice. Consequently, the uranium industry in the United States saw a prod uction decline. Although the number of uranium operations and production of domestic supply of uranium declined, several domestic uranium projects remained active, prim arily supplying foreign uranium needs. These projects were generally located in the ISL mining production st ates of Nebraska, Texas, and Wyoming. This represented a significant shift in the method that was used to r ecover uranium, from conventional

mines to ISL mines.

Numerous forecasts of worldwide uranium suppl y and demand exist. Perhaps one of the best graphical representations is from the World Nuclear Association. Fi gure 2 shows the actual uranium production rates from 1945 to 2005, as well as the demand trend that was established based on these production numbers. Figure 2 indicat es that, from the 1960s to the present, the

worldwide uranium demand has continued to in crease even though the U.S. price for uranium

has decreased.20 Source: WNA 2010

Figure 2: Uranium Production and Demand from 1945 to 2005

Figure 3 shows the uranium supply scenario fo recast by the World Nucl ear Association. The three potential requirement curves shown are base d on a variety of factors. The figure indicates that current production, as well as planned future worldwide pr oduction, may begin to fall short of demand in the next few years.

Source: WNA 2010

Figure 3: Uranium Supply Scenario from 2008 to 2030

In summary, all forecasts are for the uranium i ndustry to show growth in the next decade and continuing for the foreseeable future. Drivers fo r this trend are a worldwide need for clean energy resources, the current trend to develop domestic sources of energy, and the investment of foreign capital in the United Stat es, which is recognized as a po litically and economically stable

market in which to conduct business.21 3.2 Conventional Uranium Mining and Milling Operations

Conventional uranium mining and m illing facilities are one of two types of uranium recovery facilities that currently possess state or fede ral licenses to operate. There are currently no licensed heap leach facilities. Conventional ur anium mining and milling operations are in the minority and are a carryover from the hea vy production days of the 1970s and 1980s. Sweetwater Mill, Shootaring Canyon Mill, and Wh ite Mesa Mill represent the extent of the current conventional uranium milling operati ons that exist in the United States.

A conventional uranium mill is generally defined as a chemical plant that extracts uranium using the following process:

 Trucks deliver uranium ore to the mill, where it is crushed into smaller particles before the uranium is extracted (or leached). In most cases, sulfuric acid (H 2 SO 4 ) is the leaching agent, but alkaline solutions can also be us ed to leach the uranium from the ore. In addition to extracting 90–95% of the uranium from the ore, the leaching agent also extracts several other “heavy metal” cons tituents, including molybdenum, vanadium, selenium, iron, lead, and arsenic.

 The mill then concentrates the extracted uranium to produce a material called “yellowcake” because of its yellowish color.

 Finally, the yellowcake is transported to a uranium conversion fac ility, where it is processed through the stages of the nuclear fuel cycle to produce fuel for use in nuclear

power reactors.

Figure 4 shows a schematic of a typical conventional uranium mill.

Figure 4: Typical Conventional Uranium Mill22 Currently, there are three domestic licensed c onventional uranium mining and milling facilities and a newly licensed facility that has yet to be constructed, as shown in Table 3.

Table 3: Conventional Uranium Mining and Milling Operations

Mill Name Licensee Location Website

Sweetwater Kennecott Uranium Co/Wyoming Coal

Resource Co Sweetwater County, Wyoming None identified

Shootaring Canyon Uranium One

Americas Garfield County, Utah http://www.uranium1.com/ indexu.php?section=home

White Mesa EFR White Mesa LLC San Juan County, Utah http://www.energyfuels.com/ white_mesa_mill/

Piñon Ridge Energy Fuels Resources Corp. Montrose County,

Colorado http://www.energyfuels.com/ projects/pinon-ridge/index.html Mill Name Regulatory Status Capacity (tons/day) Sweetwater Standby,* license expires November 2014 3,000 Shootaring Canyon Standby,* license expires May 2012 750 White Mesa Operating, license expires March 2015 2,000 Piñon Ridge Development, license issued January 2011 500 (design)

* Standby means the period of time when a facility ma y not be accepting new tailings, but has not yet entered closure operations.

Instead of processing uranium ore, the conve ntional mills shown in Table 3 may process alternate feed stocks. These feed stocks are gene rally not typical ore, but rather materials that

contain recoverable amounts of ra dionuclides, rare earths, and othe r strategic metals. These feed stocks are processed, the target materials are recovered, and the wa ste tailings are discharged to the tailings impoundment. The two facilities shown in Table 3 as being in standby (Sweetwater and Shootaring Canyon) have had their operati ng licenses converted into “possession only” licenses. Prior to recommencing operation, those f acilities will be required to submit a license application to convert back to an operating licen se. EPA will review thatportion of the license application associated with NESHAP to ensure that all Subpart W requirements are incorporated into the appropriate licensing doc uments and operating procedures.

As described in Section 3.1, the rapid rise in energy costs, increased concerns about global warming, and the tremendous worldwide surge in en ergy use have all led to renewed interest in uranium as an energy resource. At the spring 2010 joint National Mini ng Association (NMA)/ NRC Uranium Recovery Workshop, the NRC identifie d numerous projects that have filed or are expected to file applications fo r new licenses, expansions of exis ting operations, or restarts of existing operations, including several proposals fo r conventional uranium recovery facilities. Contacts with the NRC and state regulatory agencies indicate that permitting and licensing actions are associated with the proposed conven tional uranium milling and processing projects shown in Table 4. Although a signi ficant uranium producer, at presen t, Texas has no interest in conventional uranium milling operations. The potent ial new mill at Piñon Ridge, Colorado, is not shown in Table 4, since its development is advan ced and it has already be en listed in Table 3.23 Table 4: Proposed New Conventional Uranium Milling Facilities

Company Site (Estimated) Application Date State

Uranium Energy Corp Anderson Project N.A. AZ Rio Grande Resources Mt. Taylor FY14 NM Strathmore Minerals Corporation Roca Honda 12-Sep NM Uranium Resources, Inc. Juan Tafoya FY 14 NM Oregon Energy, LLC Aurora Uranium Project 13-Dec OR Virginia Uranium Co les Hills N.A. VA Strathmore Minerals Corporation Gas Hills 12-Sep WY

N.A. = not available

No new construction has taken place on any milling f acilities shown in Table 4; however, as with all industries, planning precedes construction. C onsiderable planning is underway for existing and new uranium recovery operations. As with f acilities currently in standby, EPA will review the license application to ensu re that all Subpart W requireme nts are incorporated into the appropriate licensing documents and operating procedures for these proposed new mills.

No specific information is available on the type of tailings management systems intended for the proposed new conventional mills. To limit radon that could be emitted from the tailings impoundments, Subpart W requires that the tailings be disposed of in a phased disposal system with disposal cells not larger than 40 acres, or by continuous dis posal in which not more than 10 acres of exposed tailings may accumulate at a ny time. Regardless of the type of tailings management system the new milling operations select, they will all also have to demonstrate that their proposed tailings impoundment systems meet the requiremen ts in 40 CFR 192.32(a)(1).

3.2.1 Sweetwater Mill, Kennecott Mining Company, Red Desert, Wyoming

The Sweetwater project is a conventional uran ium recovery facility located about 42 mi northwest of Rawlins, Wyoming, in Sweetwater C ounty. The site is very remote and located in the middle of the Red Desert. The approximately 1,432-acre site includes an ore pad, overburden pile, and the milling area (see Figure 5). The m illing area consists of administrative buildings, the uranium mill building, a solvent extraction faci lity, and a maintenance shop. There is also a 60-acre tailings management area with a 37- acre tailings impoundme nt that contains approximately 2.5 million tons of tailings material. The Sweetwater impoundments are synthetically lined, as required in 40 CFR 192.32(a). The facility is in a standby status and has a possession only license administered by the NRC. The future plans a ssociated with this facility are unknown, but the facility has been well mainta ined and is capable of processing uranium. The standby license for this faci lity is scheduled to expire in 2014. The licensee and/or regulator

will decide whether to renew or to terminate this license.24 Figure 5: Sweetwater – Aerial View

To demonstrate compliance with Subpart W, tes ting on the facility’s ta ilings impoundment for radon emissions is conducted annually (KUC 2011) . Table 5 shows the results of that testing. The lower flux readings measured in 2009 and 2010 are a direct result of the remediation work (regrading and lagoon constructi on in the tailings impoundment ) performed in 2007 and 2008.

Table 5: Sweetwater Mill Radon Flux Testing Results

Test Date Radon Flux (pCi/(m 2 -sec)) Test Date Radon Flux (pCi/(m 2 -sec)) August 7, 1990 9.0 August 14, 2001 6.98
August 13, 1999 5.1 August 13, 2002 4.10
August 5, 1992 5.6 August 12, 2003 7.11
August 24, 1993 5.0 August 17, 2004 6.38
August 23, 1994 5.0 August 16, 2005 7.63
August 15, 1995 3.59 August 15, 2006 3.37
August 13, 1996 5.47 August 13, 2007 6.01
August 26, 1997 4.23 August 5, 2008 4.59
August 11, 1998 2.66 July 30, 2009 1.60

August 10, 1999 1.27 August 10, 2010 1.44
August 8, 2000 4.05

Source: KUC 2011, p. 625 Summary of Results

Air monitoring data were reviewed for a 26-year period (1981 to 2007). Upwind Rn-222 measurements, as well as downwind Rn-222 valu es, were available. The average upwind radon value for the period of record was 3.14 picocuri es per liter (pCi/L). The average downwind radon value for the same period was 2.60 pCi/L. These va lues indicate that there is no measurable

contribution to the radon flux from the mill tailin gs that are currently in the lined impoundment. This monitoring program remains active at the facility.

Approximately 28.3 acres of tailings are dry with an earthen cover; the remainder of the tailings is continuously covered with wa ter. The earthen cover is main tained as needed. One hundred radon flux measurements were taken on the exposed tailings, as required by Method 115 for compliance with Subpart W. The mean radon flux for the exposed beaches was 8.5 pCi/(m 2 -sec). The radon flux for the entire tailings impound ment was calculated to be 6.01 pCi/(m 2 -sec). The

calculated radon flux from the enti re tailings impoundment surface is approximately 30% of the 20.0 pCi/(m 2 -sec) standard.

3.2.2 White Mesa Mill, Energy Fuels Corporation, Blanding, Utah

The White Mesa project is a conve ntional uranium recove ry facility located about 6 mi south of Blanding, Utah, in San Juan County. The appr oximately 5,415-acre site includes an ore pad, overburden pile, and the milling area (see Figu re 6). The mill area occupies approximately

50 acres and consists of administrative buildi ngs, the uranium milling building, and ancillary facilities. The facility used a phased disposal impoundment system, and two of the 40-acre cells are open. The facility has operated intermittently in the past, and this type of operation continues

on a limited basis. The amount of mi lling that takes place, as well as the amount of uranium that is being produced, is a small fraction of the milling capacity. The uranium recovery project has an active license administered by the Utah Depa rtment of Environmenta l Quality, Division of

Radiation Control.26 Figure 6: White Mesa – Aerial View

To demonstrate compliance with Subpart W, th e radon flux from tailings surfaces is measured and reported to the State of Utah annually. As Table 6 shows, these data consistently demonstrate

that the radon flux from the White Mesa Mi ll’s tailings cells are below the criteria.

Table 6: White Mesa Mill’s Annual Radon Flux Testing, Tailings Cells 2 & 3

Year Radon Flux (pCi/(m 2 -sec))

Cell 2 Cell 3

1997 12.1 16.8

1998 14.3 14.9

1999 13.3 12.2

2000 9.3 10.1

2001 19.4 10.7

2002 19.3 16.3

2003 14.9 13.6

2004 13.9 10.8

2005 7.1 6.2 Source: Denison 2007, p. 116

The Table 6 radon flux values for 2001 and 2002 were el evated when compared to the prior years. Denison believes that these radon fluxes were largely due to th e drought conditions in those years, which reduced the moisture conten t in the interim cover placed over the inactive portions of tailings Cells 2 and 3. In addition, the beginning of the 2002 mill run, which resulted in increased activities on the tailings cells, may have contributed to these higher values. As a result of the higher radon fluxes during 2001 and 2002, additional interim cover was placed on27 the inactive portions of Cells 2 and 3. While th is effort was successful, additional cover was applied again in 2005 to further reduce the radon flux (Denison 2007).

Summary of Results

Air monitoring data were reviewed for a 2-ye ar period (2006 to 2008). The White Mesa site

utilized the MILDOS code to calculate ra don concentrations (ANL 1998), in the same calculation process that had been used since 1995. As a comparison, Denison Mines reactivated the six air monitoring stations that were used at the site. Data fr om these stations were collected for a 2-year period. The upwind and downwind meas urements showed no definable trends. At times, the upwind concentrations were the highe r values, while at other times, the downwind concentrations were the greatest. However, al l values were within regulatory standards.

The tailings facilities at the White Mesa facility consist of the following impoundments/cells (Denison 2011):

 Cell 1, constructed with a 30-millimeter (mil) PVC earthen-covered liner, is used for the evaporation of process solution (C ell 1 was previously referred to as Cell 1-I, but is now referred to as Cell 1).

 Cell 2, constructed with a 30-mil PVC earthen-c overed liner, is used for the storage of barren tailings sands. Cell 2 ha s 67 acres of surface area. Be cause 99% of the cell has a soil cover over the deposited tailings, only 0.7 acres of tailings are exposed as tailings

beaches.

 Cell 3, constructed with a 30-mil PVC earthen-c overed liner, is used for the storage of barren tailings sands and solutions. Cell 3 ha s 71 acres of surface area, and 54% of the

cell has a soil cover over the de posited tailings. The remainde r of the cell consists of tailings beaches (19%) a nd standing liquid (26%).

 Cell 4A, constructed with a geosynthetic cl ay liner, a 60-mil high-density polyethylene (HDPE) liner, a 300-mil HDPE Geonet drainage layer, a second 60- mil HDPE liner, and

a slimes drain network over the entire cell bottom. This cell was placed into service in

October 2008.

 Cell 4B, constructed with a geosynthetic clay liner, a 60-mil HDPE liner, a 300-mil HDPE Geonet drainage layer, a second 60-mil HDPE liner, and a slimes drain network

over the entire cell bottom. This cell was placed into service in February 2011.

One hundred radon flux measurements were collected on the Cell 2 beach area, and an additional

100 measurements were taken on the soil-c overed area in accordance with Method 115 for Subpart W analysis. The data were used to calculate the mean radon flux for the exposed beaches and the soil-covered area. The average radon fl ux for all of Cell 2 wa s calculated to be 13.5 pCi/(m 2 -sec), or about 68% of the 20.0 pCi/(m 2 -sec) standard.28 At Cell 3, 100 radon flux measurements were collect ed from each of the soil cover and the beach areas, as required by Method 115. The data were us ed to calculate the mean radon flux for the exposed beaches and the soil-covered area. The radon flux from the standing liquid-covered area was assumed to be zero. The average radon fl ux for all of Cell 3 wa s calculated to be 8.9 pCi/(m 2 -sec), or about 46% of the 20.0 pCi/(m 2 -sec) standard.

3.2.3 Shootaring Canyon Mill, Uranium One Incorporated, Garfield County, Utah

The Shootaring Canyon project is a conventional uranium recovery facility located about 3 mi north of Ticaboo, Utah, in Garfield County. The approximately 1,900-acre site includes an ore pad, a small milling building, and a tailings manageme nt system that is partially constructed (see Figure 7). The mill circuit operated for a very short time and generated only enough tailings to cover 7 acres of the impoundment. Although the milling circuit has been dismantled and sold, the facility is in a standby st atus and has a possession only lic ense administered by the Utah Department of Environmental Qua lity, Division of Radiation Contro l. The future plans for this uranium recovery operation are unknown. Current act ivities at this remo te site consist of intermittent environmental monitoring by consulta nts to the parent company. The standby license for this facility is scheduled to expire in 2014. The licensee and/or the regulator will decide

whether to renew or to terminate this license.

Figure 7: Shootaring Canyon – Aerial View

Summary of Results

Air monitoring data were reviewed for a 2-year period (2009 to 2010). Continuous air monitoring is not conducted at the site; rather, a 20- to 24-hour sampling event is required once per quarter as a condition of the license. The high -volume air sampler is located downwind of the tailings facility. Many sampling events during a 2-year period indica te that the downwind29 Rn-222 concentrations are around 1% of the allo wable effluent concentration limit. The two years of data reviewed indicated no trends.

The Shootaring Canyon facility operated for approxi mately 30 days. Tailings were deposited in a portion of the upper impoundment. A lower impound ment was designed but has not been built. Milling operations in 1982 produced 25,000 cubic yards of tailings, deposited in an area of 2,508 m 2 (0.62 acres). The tailings are dry except for moisture-associated occasional precipitation events; consequently, there are no b eaches. The tailings have a soil cover that is maintained by the operating company. The impound ment at Shootaring Ca nyon is synthetically lined, as required in 40 CFR 192.32(a).

One hundred radon flux measurements were collect ed on the soil-covered tailings area in accordance with Method 115. The 2009 sampling results indicated that average flux from the covered tailings was 23.3 pCi/(m 2 -sec), which exceeded the allowable 20 pCi/(m 2 -sec) regulatory limit. In response to this result, th e licensee notified the Utah Division of Radiation Control and placed additional soil cover on the ta ilings. The soil cover consisted of local borrow materials in the amount of 650 cubic yards. More sampling took place during the week of November 7, 2009. An additional 100 sample results were collected and showed that the average radon flux was reduced to 18.1 pCi/(m 2 -sec). Sampling for 2010 took place in April. Again,

100 radon flux measurements were collected. The average radon flux revealed by this sampling was 11.9 pCi/(m 2 -sec).

3.2.4 Piñon Ridge Mill, Bedrock, Colorado

The Piñon Ridge project is a permitted conventional uranium recovery facili ty in development. The permitted location is located about 7 mi east of Bedrock, Colorado, and 12 mi west of Naturita, Colorado, in Montrose County (see Fi gure 8). The approximately 1,000-acre site will

include an administration bu ilding, a 17-acre mill site, a ta ilings management area with impoundments totaling approximately 90 acres, a 40-acre evaporation pond with proposed expansion of an additional 40-acre evaporation pond as needed, a 6-acre ore storage area, and numerous access roads. The design of the tailings management area is such that it can meet the work practice standard with a synthetically li ned impoundment, a leak detection system, and a

surface area that does not exceed 40 acres. The facility has not b een constructed, but is fully licensed and administered by the Colorado Departme nt of Public Health and Environment. Also, EPA has approved the facility’s license to construct under NESHAP Subpart A of 40 CFR 61.

Current activities at the site are maintenan ce of pre-operational e nvironmental monitoring.30 Figure 8: Piñon Ridge – Aerial View

3.2.5 Conventional Mill Tailings Impoundments and Radon Flux Values

In summary, the radon data for the active mill tailings impoundments indicate that the radon

exhalation rates from the measured surfaces have exceeded the regulatory standard of 20 pCi/(m 2 -sec) at times. Two instances exist in the records that were reviewed. One instance was in 2007, when a portion of the Cotter Corpora tion impoundment did not have sufficient soil cover. Monitoring results show ed a flux rate of 23.4 pCi/(m 2 -sec). The tailings surface was covered with a soil mixture, and th e flux rate was reduced to 14.0 pCi/(m 2 -sec). The second instance in which the regulatory standard was exceeded was recorded during the 2009 sampling event at Shootaring Canyon Mill. This sampling event indicated that average flux from the covered tailings was 23.3 pCi/(m 2 -sec), caused by insufficient soil cover. Although covering tailings piles with various ot her materials (e.g., synthetics, as phalt, soil-cemen t mixtures) has been studied, covers made of earth or soil have been shown to be the most cost effective in reducing radon emissions (EPA 1989, NRC 2010). In both cases when monitoring indicated radon fluxes in excess of the standard, additional soil cover was added to the tailings, and the

radon flux rates were reduced to be low the regulatory standards.

Table 8 shows the average/calculated radon flux values, as reported by the uranium recovery

operators.31 Table 7: Mill Tailings Impoundments and Average/Calculated Radon Flux

Values*

Facility Radon Flux ( pCi/(m 2 -sec) ) Calculated Tailings Impoundment Average Radon Flux ( pCi/(m 2 -sec) ) Soil-Covered Area Tailings Beach

Sweetwater Mill No soil-covered

area 8.5 6.01

White Mesa Mill, Cell 2 13.1 50.2 13.5 White Mesa Mill, Cell 3 13.9 6.7 8.9

Shootaring Canyon Mill 15 2-year average Not applicable 15 2-year average Piñon Ridge Mill Not applicable Not applicable Not applicable * The respective uranium recovery operators supplied all data and calculations.

3.3 In-Situ Leach Uranium Rec overy (Solution Mining)

Solution, ISL or in-situ recovery (ISR), mining is defined as the leaching or recovery of uranium from the host rock (typically sandstone) by chemi cals, followed by recovery of uranium at the surface (IAEA 2005). Leaching, or more correctly the remobilization of uranium into solution, is accomplished through the injection into the ore body of a lixiviant. The injection of a lixiviant essentially reverses the geochemi cal reactions associated with the uranium deposit. The lixiviant ensures that the dissolved uranium, as well as other metals, remains in solution while it is collected from the mining zone by recovery wells.

ISL mining was first conducted in Wyoming in 1963. The research and development projects and associated pilot projects of the 1980s demonstrated soluti on mining as a viable uranium recovery technique. Initial effo rts at the solution mining proce ss were often less than ideal:

 Lixiviant injection was difficu lt to control, primarily beca use of poor well installation.

 Laboratory-scale calculations did not always perform as suspected in geological

formations.

 Recovery well spacing was poorly understood, cau sing mobilized solutions to migrate in unsuspected pathways.

 Restoration efforts were not always effective in re-est ablishing reducing conditions; therefore, some metals rema ined in solution and pre-mini ng ground water conditions were not always achievable.

Additional research and development work indica ted that mining solutions could be controlled

with careful well installation. The use of reducing agents during re storation greatly decreased the

amount of metals that were in solution. As a result of these modificat ions in mining methods, solution mining of uranium became a viable met hod to recover some uranium deposits, many of which could not be economically mined by the open pit methods typically employed by the uranium industry. Additionally, the economics of solution mining were more favorable than conventional mining and milling. Because of thes e factors, solution mining and associated processing began to dominate the uranium recove ry industry. Figure 10 shows a schematic of a typical ISL uranium recovery facility.32 Figure 9: In-Situ Leach Uranium Recovery Flow Diagram

During typical solution mining, a por tion of the lixiviant is bled off in order to control the pressure gradient within the wellfield. As Figure 10 shows, the liquid bled from the lixiviant is sent to an evaporation pond, or impoundment. The pond/impoundment may be used to dispose of the liquid via evaporation, or it may be used si mply to hold the liquid until a sufficient amount has been accumulated so that other means may be used to dispose of it (e.g., land application or irrigation, deep well disposal). Si nce Ra-226 is present in the wate r bled from the lixiviant, radon will be generated in and released from the so lution mining facility’s evaporation/holding ponds or impoundments.

The 1989 NESHAP risk assessment (EPA 1989) , although not conducted specifically for solution mining sites, is applicable to ponds/im poundments at solution mining facilities. All of the ponds at solution mining facilities are syntheti cally lined. Because of the presence of liners, none would be required to be closed. The solution mining industry is more transient in that the impoundment life is less than those at conventio nal uranium mining and milling sites. Typically, the impoundments are in the range of 1–4 acres and are built to stat e-of-the-art standards.

Two types of lixiviant solutions, loosely defined as acid or alkalin e systems, can be used. In the United States, the geology and geochemistry of most uranium ore bodi es favor the use of

“alkaline” lixiviants or bicarbonate-carbonate lixiviant and ox ygen. Other factors in the choice of33 the lixiviant are the uranium recovery efficienci es, operating costs, and the ability to achieve satisfactory ground water restorati on. The acid systems once used in the United States are still used in Eastern Europe and Asia and were us ed recently in Australia on ore bodies in saline aquifers (IAEA 2005).

The four major types of uranium deposits in th e United States are: st rata-bound (roll front), solution breccia pipe, vein, and phosphatic deposits (EPA 1995). Of these, ISL is the uranium recovery technique used mostly on strata-bound ore deposits. Strata-boun d ore deposits are ore deposits contained within a single layer of sedime ntary rock. They account for more than 90% of

the recoverable uranium and va nadium in the United States and are found in three major geographic areas: the Wyoming Basin (Wyoming and Nebraska), Colorado Plateau or Four Corners area (northwestern New Mexico, west ern Colorado, eastern Utah, and northeastern Arizona), and southern Texas. A discussion of th e origin of the uranium ore, including ore body formation and geochemistry, may be found in the reference, Technical Resource Document Extraction and Beneficiati on of Ores and Minerals , Volume 5, “Uranium” (EPA 1995). Much of

the recoverable uranium in thes e regions lends itself to ISL because of the physical and geochemical properties of the ore bodies.

Four times a year, the Energy Information Admini stration (EIA) publishes data on the status of U.S. ISL facilities. EIA (2013) identified six ISL facilities that were recovering uranium and producing yellowcake in the 2 nd quarter of 2013. Table 8 shows th ese facilities. These operations are located in NRC-regulated areas, as well as in Agreement States.

Table 8: Operating ISL Facilities

Plant Owner Plant Name County, State Cameco Crow Butte Operation Dawes, Nebraska Power Resources, Inc. dba

Cameco Resources Smith Ranch-Highland Operation Converse, Wyoming

Uranium Energy Corp. dba South Texas Mining Venture Hobson ISR Plant Karnes, Texas La Palangana Duval, Texas Mestena Uranium LLC Alta Mesa Project Brooks, Texas Uranium One USA, Inc. Willow Creek Project (Christensen Ranch and Irigaray) Campbell and Johnson, Wyoming

The two major geographical areas of ISL mining and processing have been Texas and Wyoming. These areas are well suited to this ISL mining te chnology, in that the geology associated with the mineralized zone is contained by layers of impe rvious strata. Texas is the major producer of uranium from ISL operations, followed by Wyom ing. ISL operations in South Dakota and

Nebraska recover lesser amounts of uranium.

For the 2 nd quarter of 2013, EIA (2013) identified the IS L facilities shown in Table 9 as being developed, or partially or fully permitted and li censed, or under construction. As discussed, the economics of ISL uranium recovery are conduciv e to lower grade deposits or deeply buried deposits that could not be economically rec overed with conventiona l open pit or underground mining actions.34 As the data in Table 9 show, there is considerab le interest in ISL mining operations in the U.S. uranium belt. Many of the existing ISL operations are planning for expansion by preparing the license applications and other permitting documents . It is apparent that most domestic uranium recovery will be associated w ith existing and new ISL operations.

Table 9: ISL Facilities That Are Restarting, Expanding, or Planning for New Operations

Plant Owner Plant Name County, State (existing

and planned locations) Status, 2nd Quarter 2013 Powertech Uranium Corp Dewey Burdock Project Fall River and Custer,

South Dakota Developing

Uranium One Americas, Inc. Jab and Antelope Sweetwater, Wyoming Developing Hydro Resources, Inc. Church Rock McKinley, New Mexico Partially Permitted

And Licensed Hydro Resources, Inc. Crownpoint McKinley, New Mexico Partially Permitted

And Licensed Strata Energy Inc Ross Crook, Wyoming Partially Permitted

And Licensed Uranium Energy Corp. Goliad ISR Uranium Project Goliad, Texas Permitted And

Licensed Uranium One Americas, Inc. Moore Ranch Campbell, Wyoming Permitted And

Licensed Lost Creek ISR, LLC Lost Creek Project Sweetwater, Wyoming Under

Construction Uranerz Energy Corporation Nichols Ranch ISR Project Johnson and Campbell, Wyoming Under

Construction

Table 10 shows the size of the surface impoundments at ISL facilities. It is noteworthy that the operation of these facilities doe s not require impoundme nts nearly as large as the impoundments used at conventional mills. The impoundments ar e utilized for the evaporative management of waste water. The impoundments are small because a minimal percentage of the process water

needs to be over-recovered to maintain solution fl ow to the recovery wells. The solution mining industry has used deep well injecti on for most of the waste water. Al l signs indicate that this type of waste water disposal will continue in the future.

Table 10 shows that all of the solution mining sites reviewed ar e using the deep well injection

method.35Table 10: ISL Evaporation Pond Data CompilationOperation Evaporation pond?Date pond wasconstructedSize of pondSynthetic linerunder pond?Leak detectionsystem?Deep wellinjection?Cameco, Smith Ranch East and west ponds 1986 8.6 acres YesYes, ponds havehad leaksYes, used for mostwaste water,started in 1999Cameco, Crow Butte3 commercial pondsand 2 R&D pondsR&D ponds 1990Pond 1, 2, 5850×200 ftYes YesYes, all bleedstreamPond 3, 4700×250 ftHydro Resources, CrownPointProject is licensed with the NRC, but noconstruction has taken place (personal conversation with Uranium Resources personnel)Hydro Resources,Church RockProject is licensed with the NRC, but noconstruction has taken place (personal conversation with Uranium Resources personnel)Uranium Resources Inc.,Kingsville DomeTwo 120×120 ft ponds 1990 120×120 ft Yes Yes Yes, @ 200 gpmUranium Resources Inc.,VasquezTwo 150×150 ft ponds 1990 150×150 ft Yes Yes Yes, @ 200 gpmUranium Resources Inc.,RositaTwo 120×120 ft ponds 1985 120×120 ft Yes Yes Yes, @ 200 gpmMestena, Alta Mesa Evaporation data not foundSTMV, La Palangana Evaporation data not found36 3.3.1 Radon Emission from Evapora tion and/or Holding Ponds

Unlike conventional mills, ISL facilities do not produce tailings or other solid waste products. However, they do generate significant amounts of liquid wastes during uranium extraction and aquifer restoration. During extraction, an extract ion solution (lixiviant), composed of ground water enhanced by an oxidant a nd carbonate/bicarbonate, is inject ed through wells into the ore zone. This lixiviant moves through pores in the ore body and mobilizes the uranium. The resulting “pregnant” lixiviant is withdrawn by production wells and pumped to the processing plant, which recovers the uranium. To prevent leakage of the lixiviant outside the production zone, it is necessary to maintain a hydraulic cone of depressi on around the well field. This is accomplished by bleeding off a portion of the proce ss flow. Other liquid waste streams are from sand filter backwash, resin transfer wash, and plant washdown. One method to dispose of these liquid wastes is to evaporate them from ponds. Deep well injection and land application (i.e., irrigation) are othe r methods for disposing of the liquid wastes. For these disposal methods, the waste liquid is colle cted in holding ponds until a quantity sufficient for disposal has been

accumulated.

As defined by the AEA of 1954, as amended, bypr oduct material includes tailings or waste produced by the extraction or concentration of ur anium from any ore processed primarily for its source material content (42 USC 2014(e)(2)). Clearly, waste water generated during solution mining is within this definition of byproduct material and is thus subject to the requirements of Subpart W.

The waste water contains significant amounts of radium, which will radiologically decay and generate radon gas. Radon diffuses much more slowly in water than it does in air. For example,

the radon diffusion coefficient in water is about 10,000 times smaller than the coefficient in air (i.e., on the order of 10 -5 square centimeters per second (cm 2 /sec) for water and 10 -1 cm 2 /sec for air (Drago 1998, as reported in Br own 2010)). Thus, if the tailings piles are covered with water, then most of the radon would decay before it coul d diffuse its way through the water. However, since over time periods comparable to the hal f-life of radon, there is considerable water movement within a pond, advective as well as di ffusive transport of radon from the pond water to the atmosphere must be considered. The wa ter movement is partly caused by surface wind currents, thermal gradients, mechanical disturbance from the mill discharge pipe, and biological disturbances (animals, birds, etc.). Dye moveme nt tests indicate that for shallow (less than 1 meter) pond water, advective velocities may exceed 1–2 millimeters per minute, resulting in virtually no radon containment by th e surface water. If shallow water movement is sufficient to remove radon from the tailings-water interface and transport it to the atmosphere in a short time (several hours), the radon flux from the shallow tailings is nearly as great as that from similar bare saturated tailings; hence, no significant rado n attenuation is gained by covering the tailings with water (Nielson and Rogers 1986). Consequently, in order for a pond covering a tailings pile to be effective at reducing the release of radon, the pond water must be greater than 1 meter in depth.

Additionally, if there is radium in the pond water, radon produced from that radium could escape into the atmosphere. A review of the various models used for estimating radon flux from the37 surface of water bodies indicates that the stagnant film model (also known as the two bottleneck model (Schwarzenbach et al. 2003 )), coupled with a wind correct ion equation, can be used to

estimate the radon flux based on the concentratio n of radium in the pond’s water and the assumption that radon is in secular equilibrium with the radium. The radon flux from the surface of an evaporation pond, as a function of the wind speed (for winds less than 24 miles per hour (mph)), can be estimated using this model with the following equation:

J =

w V 0.351

- -4 C

e 10 1.48  (3-1)

Where J = Radon flux (pCi/(m 2 -sec))

C w = Concentration of radium in the water (pCi/L)

V = Wind speed (m/sec)

Implicit in this model is the fact that in pond water the radon diffusion coefficient is 10 -5 cm 2 /sec

and that the thickness of the sta gnant film layer can be estimate d by an exponential relationship with wind speed (Schwarzenbach et al. 2003).

Baker and Cox (2010) measured the radium c oncentration in an ev aporation pond at the Homestake Uranium Mill Site at 165 pCi/L. Assuming a direct conversion to Rn-222 (165 pCi/L), the flux is estimated from equation 3-1 at 1.65 pCi/(m 2 -sec). This is comparable to measurements of the flux, which averaged 1.13 pCi/(m 2 -sec). However, the Homestake

measurement method did not allow the measurem ent of wind-generated radon fluxes, as the

collar used to float the canister makes the wi nd speed zero above the area being measured. No

data were found for measurements of the radon flux on evaporation ponds versus wind speed.

The model should not be used for wind speeds ab ove 10 meters per second (m/sec) (24 mph). However, this is not expected to be a major limitation for estimating normal radon releases and impacts from operational evaporation ponds.

Using actual radium pond concentrations and wi nd speed data in equation 3-1, the radon pond flux was calculated from several existing ISL s ites (SC&A 2010). Results showed that the radon flux ranged from 0.07 to 13.8 pCi/(m 2 -sec). This indicates that the radon flux above some evaporation ponds can be significant (e.g., can exceed 20 pCi/(m 2 -sec)). If such levels occur, there are methods for reducing the radium concen tration in the ponds, the most straightforward being dilution. However, this solution is tempor ary, as evaporation will eventually increase the concentration. A second method is to use barium chloride (BaCl 2 ) to co-precipitate the radium to the bottom of the pond. The radon generated at th e depths of the bottom sediments will decay before reaching the pond surface.

Again using actual ISL site data, the total annu al radon release from the evaporation ponds was calculated and compared to the reported total radon release fro m three sites. The evaporation pond contribution to the site’s total radon release was small (i .e., less than 1%).

Two additional sources of radon release were inve stigated: the discharge pipe and evaporation sprays. The discharge pipe is used to discharge bl eed lixiviant to the evaporation pond. Radon38 releases occur when the bleed lixiviant exits the pipe and enters the pond. The investigation

found that these radon releases are normally calculated using the methodology in NUREG-1569, Appendix D (NRC 2003); thus, this source is currently included in the total radon releases reported for an ISL site. For a “typical” ISL, with a purge water radon concentration of

3.2×10 5 pCi/L and a purge rate of 5.5×10 5 liters per day (L/d) or about 100 gallons per minute (gpm), NUREG-1569, Appendix D, calculated the radon released from the discharge pipe to be 64 Ci/yr.

Spray systems are sometimes used to enhance ev aporation from the ponds. A model to calculate radon releases during spray operation was deve loped (SC&A 2010). Also, data from ISL ponds

were used to estimate this source of radon rel ease. The radon releases from spray operations were reported to range from <0.01 to <3 pCi/(m 2 -sec) (SC&A 2010). Furthermore, operation of the sprays would reduce the radon concentration within the pond; therefor e, the normal radon release would be depressed once the sprays are tu rned off (until the radon has had an opportunity to re-equilibrate with the radium). Hence, opera tion of spray systems to enhance evaporation is not expected to significan tly increase the amount of radon released from the pond.

3.4 Heap Leaching

Heap leaching is a process by which chemicals are used to extract the uranium from the ore. A large area of land is leveled with a small gradie nt, layering it with HDPE or linear low-density polyethylene (LLDPE), sometimes with clay, si lt or sand beneath the plastic liner. Ore is extracted from a nearby surface or an underground mine. The extracted ore will typically be run through a crusher and placed in heaps atop the plastic. A leaching agent (often H 2 SO 4 ) will then be sprayed on the ore for 30–90 days. As the le aching agent percolates through the heap the

uranium will break its bonds with the oxide rock and enter the solution. The solution will then flow along the gradient into collecting pools from which it will be pumped to an onsite processing plant.

In the past, there have been a few commercial heap leach facilities, but currently none are operating. However, this type of facility can be rapidly constructed and put into operation. Planning and engineering have begun for two h eap leach facilities. At the spring 2010 joint NMA/NRC Uranium Recovery Workshop, the NRC id entified two proposed heap leach projects, one in Wyoming and the other in New Mexico, as shown in Table 11. In addition to these two projects, Cotter has indicated to the Colorado Department of Pub lic Health and Environment that

it intends to retain the use of the secondary impoundment at its Cañon City site for heap leaching in the future (Hamrick 2011).

Table 11: Anticipated New Heap Leach Facilities

Owner Site State

Energy Fuels 4 Sheep Mountain Wyoming

Uranium Energy Corporation Grants Ridge New Mexico

Source: NMA 2010

4 Energy Fuels acquired the Sheep Mountain Project through its acquisition of Titan Uranium Inc. in February 2012 ( http://www.energyfuels.com/devel opment_projects/sheep_mountain/ , accessed 9/25/2013).39 Higher uranium prices will likely lead to the pr ocessing of low-grade ore currently found in the uranium districts in Wyoming and New Mexico. Mu ch of the low-grade ore currently exists in spoil piles that were not economical to truck to milling operations. Little processing equipment is necessary to bring heap leach operations on lin e. Additionally, minimal personnel are necessary to operate and monitor such an operation. Howeve r, the application of NESHAP Subpart W to heap leach facilities should be clarified (see Sect ion 5.0). At a minimum, it is expected that these types of facilities will be limited in acreage according to the Subpart W standard and will be required to have synthetic liners with monitored leak detection systems.

Attempts have been made at heap-leaching lo w-grade uranium ore, generally by the following

process:

 Small pieces of uncrushed ore are placed in a pile, or “heap”, on an impervious pad of plastic, clay, or asphalt, to prevent uranium and other chemicals from migrating into the

subsurface.

 An acidic solution is then sp rayed onto the heap, which dissolves the uranium as it migrates through the ore.

 Perforated pipes under the heap collect th e uranium-rich solu tion, and drain it to collection basins, from where it is piped to the processing plant.

 At the processing plant, uranium is concentr ated, extracted, stripped, and dried to produce a material called “yellowcake.”

 Finally, the yellowcake is packed in 55-gall on drums to be transported to a uranium conversion facility, where it is processed through the stages of the nuclear fuel cycle to produce fuel for use in nuclear power reactors.

Figure 10 shows a schematic of a typical h eap-leaching uranium r ecovery facility.40 Figure 10: Typical Heap-Leachin g Uranium Recovery Facility

Heap-leaching was not an industry trend; rather, it was an atte mpt to process overburden that

contained a minimal concentration of uraniu m. Production records associated with this processing technique were not maintained, but ce rtainly the technique re presented less than 1%

of the recovered uranium resources. Almost all of the conventional uran ium recovery operations

were stand-alone facilities that includ ed the mining, milling, processing, drying, and containerization of the yellowcake product. The yellowcake product was then trucked to processing facilities that refined the raw materials into the desired product.

3.4.1 Sheep Mountain Mine, Energy Fu els, Fremont County, Wyoming

The Sheep Mountain mine, located at approxim ate 42o 24’ North and 107o 49’ West, has operated as a conventional underg round mine on three separate occasions. Mining on the Sheep Mountain property started in 1956 and continued in several open pit and underground operations until 1982. The Sheep I shaft was sunk in 1974, followed by the Sheep II shaft in 1976. Production from the Sheep I shaft in 1982 was repor ted to be 312,701 tons at an average grade of

0.107% U 3 O 8 (triuranium octoxide ) . In 1987, an additional 12,959 tons at 0.154% U 3 O 8 were produced, followed by 23,000 tons at 0.216% U 3 O 8 in 1988. The Sheep II shaft has had no production. The Congo Pit is essentially a si ngle open pit which was being readied for development in the early 1980s, but plans were ne ver realized because of the collapse of the uranium market. Feed from Sheep Mountain was pr ocessed at the Split Rock Mill, which was located north of Jeffrey City. Figur e 11 shows the Sheep Mountain mine.41 Figure 11: Sheep Mountain – Aerial View

Energy Fuels plans to develop the Sheep M ountain mine with both conventional underground and open pit mining, followed by heap leach extr action of the uranium with an ion-exchange recovery plant producing up to 1.5 million pounds of U 3 O 8 per year. Energy Fuels’ plans include the development of both the Sheep I and Sheep II underground mines, with access from twin declines. At its peak production, the undergr ound mine will produce approximately 1.0 million pounds U 3 O 8 per year. The Congo Pit will also be developed, producing an average of 500,000 pounds U 3 O 8 per year. Recovery of the uranium will include heap leach pads using

H 2 SO 4 and a conventional recovery plant, thr ough to yellowcake production on site. Assuming no re-use of heap pads, there will be 100 heap leaching cells, each with a capacity of 66,000 tons of material stacked to a height of 25 feet (f t) over an area of 40 ft by 100 ft. The mineral processing rate will be 500,000 tons per year or gr eater (Titan Uranium 2010).

Currently, the Wyoming Department of Environmental Quality ha s issued a fully bonded mining permit to Titan (now Energy Fuels). Energy Fuel s is in the process of developing a source material license application for submittal to the NRC around mid-2011. The review and approval process is expected to take about 2 years (i.e ., the NRC will complete it in mid-2013). Finally, the Plan of Operation (POO) is being developed a nd expected to be submitted to the U.S. Bureau of Land Management also around mid-2011. Submittal of the POO will trigger development of an environmental impact statement (EIS). This POO/EIS process is expect ed to be completed by the end of 2012 (Titan Uranium 2011).

3.5 Method 115 to Monitor Radon Emissions from Uranium Tailings

Subpart W (40 CFR 61.253) requires that compli ance with the existing emission standards for uranium tailings be achieved through the use of Method 115, as prescribed in Appendix B to

40 CFR 61. Method 115 consists of numerous secti ons that discuss the monitoring methods that42 must be used in determining the Rn-222 emi ssions from underground uranium mines, uranium mill tailings piles, phosphogypsum stacks, and othe r piles of waste material that emits radon.

For uranium tailings piles, Method 115, Section 2.1.3, specifies the minimum number of flux measurements considered necessary to determin e a representative mean radon flux value for each type of region on an operating pile:

 Water covered area—no measurements requ ired as radon flux is assumed to be

zero.

 Water saturated beaches—100 radon flux measurements.

 Loose and dry top surface—100 radon flux measurements.

 Sides—100 radon flux measurements, except wh ere earthen material is used in

dam construction.

The requirement of 300 measurements may result in more measurements then are necessary under the Subpart W design standards. For exam ple, under design standard 40 CFR 61.252(b)(2) for continuous disposal, only 10 acres are uncovered at one time . The 300 flux measurements on a 10-acre area translate into one measurement every 1,500 ft 2 , or one every 40 ft. At the time Method 115 was developed and amended to Appe ndix B (i.e., 1989), the uranium tailings areas were much larger than the Subpart W desi gn standards presently allow. For example, DOE/EIA-0592 (1995) indicates that some mills had tailings areas of over 300 acres (although not necessarily in a single pile).

Method 115, Section 2.1.6, indicate s that measuring “radon flux i nvolves the adsorption of radon on activated charcoal in a large-area collector.” Since 1989, there have been advances in methods of measuring radon flux. George (2 007) is particularly relevant in terms of radon measuring

devices:

In the last 20 years, new instruments and methods were developed to measure radon by using grab, integrating, and continuous modes of sampling. The most
common are scintillation cell monitors, acti vated carbon collectors, electrets, ion chambers, alpha track detectors, pulse and current ionization chambers, and solid state alpha detectors.

In George (2007) radon detection is divided into:

I. Passive integrati ng radon measurements

(1) Activated carbon collectors of the open face or diffusion barrier type. Charcoal canisters often employ a ga mma spectrometer to count the radon daughters as surrogates (bismuth-214, fo r example). Liquid scintillation vials also use alpha and beta counting. About 70% of radon measurements in the

United States are canister type.43 (2) Electret ion chambers are being used for 2–7 days duration to measure the voltage reduction (drop). The voltage drop on the electrets is proportional to

the radon concentration. About 10%–15% of radon measurements use this methodology.

(3) Alpha track detectors are used for long-term measurements. Alphas from radon penetrate a plastic lattice, which is etched with aci d, and the resulting

tracks are counted. There is some use in the United States, but this is more popular in Europe.

II. Passive or active con tinuous radon measurements

(1) Scintillation cell monitors mostly include the flow-through type.

(2) Current and pulse ionization chambers (mostly passive).

(3) Solid state devices are either passive or active if they use a pump to move air through the sensitive volume of the monitor like the RAD 7, which uses a solid state alpha detector (passive impl anted planar silicon (PIPS) detector).

Additionally, the Oak Ridge Institute for Scie nce and Education (ORISE) compared various radon flux measurement techniques (ORISE 2011), in cluding activated char coal containers, the

Electric Passive Environmental Radon Monito r (E-PERM) electret ion chamber, the AlphaGUARD specialized ionization chamber, semiconductor detectors to measure radon daughters, and ZnS(Ag) (silver doped zinc sulfide) scinti llation detectors. ORIS E stated that the last two techniques were not yet commercially av ailable and that the Al phaGUARD detector was “expensive,” and thus they ar e not currently candidates for radon flux monitoring of uranium tailings. Comparing the activated charcoal containers to the E-PERM, ORISE found that while both were easy to operate and relatively inexpens ive, the E-PERM showed smaller variations in measurements, and the activated charcoal contai ners had higher post-processing costs. The only disadvantage of the E-PERM was that its Teflon di sks must be replaced after each use. Based on this comparison, ORISE recommended that for a large number of measurements, such as those needed to comply with Subpart W, E-PERM flux monitors would be best.

This brief review of Method 115 demonstrates that its use can still be considered current for monitoring radon flux from uranium tailings. Howeve r, it is important to note that the specific design protocols were developed for use at larger tailings im poundments. Alternatively, many commercial enhancements to that design are wide ly available and in us e today. Other forms of passive detectors, as well as active measurement detectors, are also acceptable alternatives to

demonstrate conformance with the standard. In addition, the method as currently written has some elements and requirements that should be reviewed and possibly re vised, particularly the location and the frequency of measurement. These would be better based on statistical

considerations or some other technical basis. A dditional discussion of the continued applicability of Method 115 appears in SC&A 2008, ORISE 2011, and George 2007.44 4.0 CURRENT UNDERSTANDING OF RADON RISK

Subpart W regulates the emission of radon from ope rating uranium recovery facility tailings. To enhance the understanding of the need for Subpart W, this se ction presents a qualitative review and analysis of changes in the analysis of th e risks and risk models associated with radon releases from uranium recovery tailings sin ce the publication of the 1989 BID (EPA 1989). After presenting some brief radon basics , the analysis focuses on three areas that have evolved: radon progeny equilibrium fractions, empirical risk factors, and the development of dosimetric risk factors. Finally, Section 4.4 presen ts the results of a risk asse ssment performed using current methodology (i.e., CAP88, Version 3 (TEA 2007)), 2011 estimated population distributions, and

historical radon release data. Sec tion 4.4 also discusses and compares the current calculated risks

to the 1989 risk assessment resu lts, presented in Section 2.3.

4.1 Radon and Dose Definitions

Rn-222 is a noble gas produced by radioactive d ecay of Ra-226. As shown in Figure 12, one of the longer-lived daughters in the uranium (U)- 238 decay series, Ra-226 is a waste product in uranium tailings and liquids from uranium recove ry facilities. These include mills, evaporation and surge ponds, typically found in ISL facilities, and heap leach piles. Radium (and its daughter radon) is also part of the natural radiation environment and is ubiquitous in soils and ground water along with its parent uranium.

Figure 12: Uranium Decay Series

Radon, with a half-life of 3.8 days, decays into a series of short half-life daughter products or progeny. Being chemically inert, most i nhaled radon is quickly exhaled. Radon progeny, however, are charged and electrosta tically attach themselves to inhalable aerosol particulates, which are deposited in the lung or directly onto lung tissue. These progeny undergo decay,45 releasing alpha, beta, and gamma radiation that interacts direct ly with lung tissue. Of these interactions, alpha particles from polonium- 218 and polonium-214 are the most biologically damaging. The resulting irritation of lung cell tissue particularly from these alpha particles enhances the risk of developing a lung cancer. Determining an estimate of the risk of developing a cancer is of primary importance to establis hing the basis for any regulatory initiatives.

4.2 Radon Risk Factors

In 1988, the National Research Council’s Comm ittee on the Biological Effects of Ionizing Radiation (BEIR) presented a re port on the health risks of radon (BEIR IV, NAS 1988). BEIR IV derived quantitative risk estimates for lung cancer from analyses of epidemiologic data from underground miners. The risk factor presented in BEIR IV for radon was 350 cancer deaths per million person-WLMs 5 of exposure.

The International Commission on Radiological Protection (ICRP), in its Publication 50 (ICRP 1987), addressed the questi on of lung cancer risk from i ndoor radon daughter exposures. The ICRP Task Group took a direction quite differ ent from that of the BEIR Committee. The Task Group reviewed published data on three mi ner cohorts: U.S., Ontario, and Czech uranium

miners. When the ICRP 50 relative risk model was run with the 1980 U.S. life table and vital statistics, the combined male and female refe rence risk was calculate d in the 1989 BID to be

4.2×10 -4 cancer deaths per WLM.

In the 1989 BID, EPA averaged the male and female BEIR IV and ICRP 50 risk coefficients and adjusted the coefficients for background, so that the risk of an excess lung cancer death for a combined population (men and women) was 3.6×10 -4 WLM -1 , with a range from 1.4×10 -4 to

7.2×10 -4 WLM -1 (EPA 1989).

In addition to epidemiological radon risk coeffici ents, dosimetric models have been developed as a widely acceptable approach to determine the effects of exposures to radon progeny. One of the principal dosimetric models used to calculate doses to the lung followi ng inhalation of radon and its daughters is the ICRP Huma n Respiratory Tract Model (HRT M), first introduced in ICRP Publication 66 (ICRP 1994). The ICRP used the HRTM to develop a compilation of effective

dose coefficients for the inhalation of radionuclid es, presented in Publication 72 (ICRP 1996).

Shortly after the publication of ICRP Publication 72, and using th e information in that report, EPA developed Federal Guidance Report 13 (FGR 13) (EPA 1999) 6 . In addition to the risk factors given in FGR 13 itself, the FGR 13 CD Supplement (EPA 2002) provides dose factors, as well as risk factors, for vari ous age groups. For this study, the dose and risk factors from the

5 Radon concentrations in air are commonly expresse d in units of activity (e.g., picocuries (pCi) or becquerels) per unit volume (e.g., liters (L)); however, radon progeny concentrations are commonly expressed as working levels (WLs). In a closed volume, the conc entration of short-lived ra don progeny will increase until equilibrium is reached, under these conditions, each pCi/L of radon will give rise to (almost precisely) 0.01 WL, or 100 pCi/L = 1 WL (EPA 2003). Exposure to 1 WL for 1 month (i.e., 170 hours) is referred to as 1 working level month (WLM).

6 Since FGR 13 was published, several organizations ha ve produced updated radiation risk estimates. EPA 2011 reviewed the update risk estimates and concluded that the new mortality estimates do not differ greatly from

those in FGR-13.46 FGR 13 CD Supplement were used to calculate the dose and risk due to exposure to 1 WLM of radon and its progeny. The calculation assumed a radon airborne concentr ation of 100 pCi/L, a radon progeny equilibrium fracti on of 0.4, a breathing rate of 0.9167 cubic meters per hour (m 3 /hr), and an exposure duration of 170 hours.

The results of this calculation demonstrate that the FGR 13 based radon progeny lung dose

conversion factor is between about 2.1 to 7.0 m illisieverts (mSv)/WLM, depending on the age of the individual being exposed. The results also sh ow that the lifetime fatality coefficient from lung exposure is between about 6×10 -4 to 2.4×10 -3 WLM -1 , depending on the exposed individual’s age. This agrees well with the factor calculated from empirical data.

In conclusion, the radon progeny ri sk factor from FGR 13 of 6×10 -4 WLM -1 used in this analysis falls within the risk factor range identified in the 1989 BID (i.e., 1.4×10 -4 to 7.2×10 -4 WLM -1 ),

and is about 67% la rger than the 3.6×10 -4 WLM -1 radon progeny risk factor used in the 1989 BID. Thus, the radon progeny risk factor used in this Subpart W analysis updates the risk factor

used in the 1989 BID to reflect the current understa nding of the radon risk, as expressed by the

ICRP and in FGR 13.

4.3 Computer Models

Various computer models that could be used to calculate the doses and ri sks due to the operation

of conventional and ISL uranium mines were compared. Seven computer programs were considered for use in the uranium tailings radon risk assessment: CAP88 Version 3.0, RESRADOFFSITE, MILDOS, GENII, MEPAS, AIRDOS, and AERMOD. A detailed selection process was used to select the program from the first five programs listed. AIR DOS was not included in the detailed selection process, since it is no longer an independent program, but has been incorporated into CAP88 Version 3.0. Because it calculates only atmospheric dispersion, but not radiological doses or risks, AERMOD was also not included. The five remaining programs

received a score between 0 and 5 for each of the following 11 criteria: (1) Exposure Pathways Modeled, (2) Population Dose/Risk Capability, (3 ) Dose Factors Used, (4) Risk Factors Used, (5) Meteorological Data Processing, (6) Sour ce Term Calculations, (7) Verification and Validation, (8) Ease of Use/User Friendly, (9 ) Documentation, (10) Sensitivity Analysis Capability, and (11) Probabilistic Analysis Ca pability. Also, each crit erion had a weighting factor of between 1 and 2. The total weighted score was calculated for each code, and CAP88

was selected for use in this evaluation. A more complete discussion of th e selection of the risk assessment computer code appears in SC&A 2010.

As described in Section 2.3, the 1989 BID used the computer codes AIRDOS-EPA, RADRISK,

and DARTAB to calculate the risks due to radon releases from ur anium tailings. Subsequent to the publication of the 1989 BID, CAP88 Vers ion 3.0 was produced. CAP88 Version 3.0 was originally composed of the AI RDOS-EPA and DARTAB computer codes and the dose and risk factors from RADRISK (see Sec tion 2.3). CAP88 Version 3.0 was first used for DOE facilities to calculate effective dose equivalents to memb ers of the public to ensure compliance with the then-issued NESHAP Subpart H rules (TEA 2007) . Currently, CAP88 Version 3.0 incorporates

the dose and risk factors from FGR 13 for de termining risks from radionuclides, including the radon decay daughters.47 When calculating doses and risk from Rn-222, CAP88 Version 3.0 can be run in two different modes, either normally or in the “radon only” mode. When run in the normal mode, CAP88 Version 3.0 treats radon and its progeny as a ny other radionuclide and its progeny would be treated. That is, the radon is decayed as it trav els from the release point to the dose receptor location, and the in-growth of the progeny is calculated. At th e dose receptor location, doses are calculated assuming all the normal exposure path ways, including inhalation and air submersion, that are normally associated with radon doses, a nd also the exposure pathways from the longer lived radon progeny that deposit on to the ground, including ground shine and food ingestion. To perform these calculations, CAP88 Version 3.0 used the dose and risk factors from FGR 13.

In the “radon only” mode, CAP88 Version 3.0 calculates the risk from the radon WL concentration, but not the dose. The annual risk to an individual or popu lation at a location is simply the WL concentration multiplied by a risk coefficient. The risk coefficient used by

CAP88 Version 3.0 is 1.32 cancer fata lities per year per WL. Although this risk coefficient is not documented in any of the CAP88 Version 3.0 user manuals, so its origin is unknown, it can be derived from the CAP88 Version 3.0 output files. A risk coefficient of 1.32 WL-year -1 is equivalent to 2.56×10 -2 cancer deaths per WLM, which is ab out two orders of magnitude larger

than the risk coefficient discussed in Sec tion 4.2. Thus, CAP88’s “radon only” mode was not

used to calculate the risk estimates that are su mmarized in the next section. Rather, the risk estimates are based on CAP88’s atmospheric tr ansport model (for radon decay and progeny buildup) and the radionuclide-spec ific risk factors from FGR 13.

4.4 Uranium Recovery Facility Ra don Dose and Risk Estimates

To perform the CAP88 dose/risk an alysis, three types of data were necessary: (1) the distribution of the population living within 80 km (50 mi) of each site, (2) th e meteorological data at each site, particularly the wind speed, wind directi on, and stability class, a nd (3) the amount of radon annually released from the site.

Dose/risk assessments were performed for the uranium recovery sites identified in Table 12,

which include conventional uranium mills and IS L mines, plus two hypothetical generic sites developed to represent the west ern and eastern United States.

Table 12: Uranium Recovery Sites Analyzed

Mill / Mine Type State Regulator Latitude Longitude deg min sec deg min sec
Crow Butte In-Situ Leach NE NRC 42 38 41 -103 21 8

Western Generic Conventional NM NRC 35 31 37 -107 52 52 Alta Mesa 1, 2, 3 In-Situ Leach TX State 26 53 59 -98 18 29 Kingsville Dome 1,3 In-Situ Leach TX State 27 24 54 -97 46 51

White Mesa Mill Conventional UT State 37 34 26 -109 28 40

Eastern Generic Conventional VA NRC 38 36 0 -78 1 11 Smith Ranch - Highland In-Situ Leach WY NRC 43 3 12 -105 41 8 Christensen/Irigaray In-Situ Leach WY NRC 43 48 15 -106 2 7

Sweetwater Mill Conventional WY NRC 42 3 7 -107 54 4148 Normally, the population doses and risks are calcul ated out to a distance of 80 km (50 mi) from the site. Therefore, it was necessary to know th e population to a distance of 80 km from each site in each of the 16 compass directions. This info rmation is not normally available from U.S. Census Bureau data. However, in 1973, EPA wrote a computer program, SECPOP (Sandia 2003), which would convert census bl ock data into the desired 80-km population estimates for any specific latitude and longitude within the continental United States. The NRC adopted this program to perform siting review s for license applications and has updated the program to use the 2000 census data. SC&A (2011) used the SECPOP program to estimate the population distribution around each site; that pop ulation was then modified to account for changes in the population from 2000 to 2010.

For those sites where site-specifi c meteorological data were iden tified, those site-specific data were used. For other sites, CAP88 Version 3.0 is provided with a weather library of meteorological data from over 350 National Weathe r Service stations. Fo r sites without sitespecific meteorological data, data from the National Weather Service station nearest the site were

used.

Annual radon release estimates were determ ined for each site based on the available documentation for the site. For example, some sites reported their estimated radon release in their semiannual release reports, wh ile other sites calculated their radon release as part of their license application or renewal application. Fina lly, for some sites, th e annual radon release estimates were obtained from the NRC-produced, site-specific environm ental assessment. If multiple documents provided radon release estimate s for a particular site, the estimate from the

most recent document was used. Consistent w ith the 1989 assessment, in order to bound the risks, radon releases were estimated from both pr ocess effluents and impoundments. Likewise, if

both theoretical and actual radon re lease values were id entified for a site, th e actual radon release value was given preference.

Additional descriptions of each site’s populat ion, meteorology, and radon source term may be

found in SC&A 2011. Doses and risks to the RMEI and to the population liv ing within 80 km of the facility were calculated. The RMEI is someone who lives near the facili ty and is assumed to have living habits that would tend to maximize his/her radiation exposure. For example, the RMEI was assumed to eat all of his/her vegetabl es from a garden located nearest the facility, which is contaminated with radon progeny as a resu lt of radon releases fro m the facility. On the other hand, population doses and ri sks are based on the number of individuals who live within 80 km of the facility. These people are also a ssumed to eat locally grown vegetables, but not necessarily from the garden located nearest the facility. The RMEI’s dose and risk are included within the population dose and risk, since he/she lives within the 80-km radius.

Table 13 presents the RMEI and population doses and risks due to the maximum radon releases

estimated for each uranium site.49 Table 13: Calculated Maximum Total A nnual RMEI, Population Dose and Risk

Uranium Site Maximum

Radon Release (Ci/yr) Annual Dose LCF (a, b) Risk (yr -1 )

Population (person-rem) RMEI (mrem) Population RMEI

Sweetwater 2,075 0.5 1.2 2.9E-06 6.0E-07

White Mesa 1,750 5.2 12.0 3.4E-05 6.4E-06
Smith Ranch - Highlands 36,500 3.7 1.5 2.3E-05 7.7E-07

Crow Butte 8,885 2.7 3.3 1.7E-05 1.7E-06
Christensen/Irigaray 1,600 3.8 1.9 2.4E-05 9.9E-07

Alta Mesa 740 21.6 11.5 1.3E-04 6.1E-06

Kingsville Dome 6,958 58.0 11.3 3.8E-04 6.1E-06

Eastern Generic 1,750 200.3 28.2 1.4E-03 1.6E-05

Western Generic 1,750 5.1 6.0 2.7E-04 7.7E-06

(a) Latent Cancer Fatalities

(b) In this table all risks are presented as LCF risks. If it is de sired to estimate the morbidity risk, simply multiply the LCF ri sk by 1.39.

Table 14 presents the RMEI and population doses and risks due to the av erage radon releases

estimated for each uranium site. The risks were ba sed on average radon releases to make it easier

to convert these annual risk valu es into lifetime risk values. Th is conversion is done by simply multiplying the Table 14 values by the number of years that the facility operates for the population risk, or by the length of time that the indi vidual lives next to the facility for the RMEI

risk.

Table 14: Calculated Average Total A nnual RMEI, Population Dose and Risk

Uranium Site Average Rado

n Release

(Ci/yr) Annual Dose LCF (a) Risk (yr -1 )
Population (person-rem) RMEI (mrem) Populatio

n RMEI

Sweetwater 1,204 0.3 0.7 1.7E-06 3.5E-07

White Mesa 1,388 3.0 7.0 2.0E-05 3.7E-06 Smith Ranch - Highland

s 21,100 2.2 0.9 1.3E-05 4.5E-07

Crow Butte 4,467 1.6 1.9 1.0E-05 1.0E-06

Christensen/Irigaray 1,040 2.2 1.1 1.4E-05 5.7E-07

Alta Mesa 472 12.5 6.7 7.6E-05 3.6E-06
Kingsville Dome 1,291 33.6 6.6 2.2E-04 3.5E-06

Eastern Generic 1,388 116.3 16.4 7.9E-04 9.2E-06

Western Generic 1,388 3.0 3.5 1.6E-04 4.4E-06

(a) Latent Cancer Fatalities

The dose and risk to an average member of th e population within 0–80 km of each site may be calculated by dividing the population doses a nd risks from Table 13 and Table 14 by the population for each site. Table 15 shows the results of that calculation.50 Table 15: Dose and Risk to an Average Member of the Population

Uranium Site Dose (mrem) LCF (a) Risk (yr -1 )
Average

Release Maximum

Release Average

Release Maximum

Release

Sweetwater 0.03 0.05 1.6E-07 2.7E-07

White Mesa 0.15 0.25 9.6E-07 1.6E-06
Smith Ranch - Highlands 0.03 0.05 1.7E-07 2.9E-07

Crow Butte 0.05 0.08 3.1E-07 5.3E-07
Christensen/Irigaray 0.06 0.11 3.8E-07 6.6E-07

Alta Mesa 0.03 0.05 1.6E-07 2.7E-07

Kingsville Dome 0.07 0.13 4.8E-07 8.3E-07

Eastern Generic 0.05 0.09 3.7E-07 6.4E-07

Western Generic 0.04 0.07 2.2E-06 3.8E-06

(a) Latent Cancer Fatalities

As Table 15 shows, the annual latent cancer fata lity (LCF) risk to an average member of the population surrounding a uranium site ranges from 1.6×10 -7 to 1.6×10 -6 for the seven actual sites,

and from 3.7×10 -7 to 3.8×10 -6 for the two hypothetic al generic sites.

The study estimated that the annual fatal can cer risk to the RMEI ranges from 3.5×10 -7 to

6.4×10 -6 for the seven actual sites, and from 4.4×10 -6 to 1.6×10 -5 for the two hypothetical generic sites. The highest annual individual risk occurr ed at the Eastern Gene ric site, which is not surprising considering that the nearest individual wa s assumed to reside only about 1 mi from the hypothetical site. It is likely that during the site selection process for an actual facility, a site this

close to residences would be eliminated and/or the design of the facility would include features for reducing radon emissions in order to reduce the RMEI risk.

The lifetime risk would depend on how long an individual was exposed. For example, for the seven actual sites analyzed, assuming that the uranium mill operates for 10 years, then the

lifetime fatal cancer risk to the RMEI would be 3.5×10 -6 to 3.7×10 -5 . Alternatively, if it is assumed that an individual was exposed for hi s/her entire lifetime (i .e., 70 years), then the

lifetime fatal cancer risk to the RMEI would be 2.45×10 -5 to 2.59×10 -4 . For the two hypothetical generic sites, the lifetime fatal cance r risk to the RMEI would be 4.4×10 -5 to 9.2×10 -5 assuming 10 years of mill operation, or 3.1×10 -5 to 6.44×10 -5 assuming 70 years of mill operation. The lifetime risk calculation uses only the average radon release results, because while the maximum could occur for a single year, it is unlikel y that the maximum would occur for 10 or 70 continuous years.

The study also estimated that th e risk to the population from a ll seven real uranium sites is between 0.0005 and 0.0009 fatal cancers per year , or approximately one case every 1,080 to 1,865 years to the 1.8 million persons living within 80 km of the sites.51 4.5 Summary of Radon Risk

This section described the evolution in the unde rstanding of the risk pr esented by radon and its progeny since the 1989 BID was published. Additiona lly, the computer code CAP88 Version 3.0 was used to analyze the radon risk from seven operating uranium recovery sites and two generic

sites.

The lifetime MIR calculated using data from seve n actual uranium recovery sites was determined

to be between 2.45×10 -5 to 2.59×10 -4 . The low end of the rang e is lower than the 3×10 -5 lifetime MIR reported in the 1989 rulemaking for existi ng impoundments (see Section 2.3.1), while the high end of the range is sli ghtly higher than the 1.6×10 -4 lifetime MIR reported in the 1989 rulemaking for new impound ments (see Section 2.3.2).

In protecting public health, EPA strives to pr ovide the maximum feasible protection by limiting radon exposure to approximately 1 in 10,000 (i.e., 10 -4 ) the lifetime MIR. Although the calculated high end of the lif etime MIR range is above 10 -4 , the assumptions that radon releases occur continuously for 70 years a nd that the same RMEI is exposed to those releases for the entire 70 years are very conservative.

Similarly, the risk assessment estimated that th e risk to the populati on from all seven real

uranium sites is between 0.0005 and 0.0009 fatal can cers per year, or approximately one case every 1,080 to 1,865 years among the 1.8 million persons living within 80 km of the sites. For the 1989 rulemaking, the estimated annual fatal can cer incidence to the 2 million people living within 80 km of the sites was 0.0043, which was less than one case every 200 years for existing impoundments, and 0.014, or approximately one cas e every 70 years for new impoundments (see Sections 2.3.1 and 2.3.2).

5.0 EVALUATION OF SUBPART W REQUIREMENTS

The evaluation of Subpart W requirements required an alyses of several item s to determine if the current technology had advanced since the promul gation of the rule. These topics are listed below, along with the key issues addressed in this report to determine whether the requirements of Subpart W are necessary and sufficient.

5.1 Items Reviewed and Key Issues

Each of these items will be revi ewed with reference to the relevant portions of this document:

(1) Review and compile a list of existing and pr oposed uranium recovery facilities and the containment technologies being us ed, as well as those proposed.

Key Issue – The standard should be clarified to ensure that all owners and operators of uranium recovery facilities (conventional mills , ISL, and heap leach) are aware that all

of the structures and facilit ies they employ to manage ur anium byproduct material (i.e., tailings) are regulated under Subpart W.52 (2) Compare and contrast those technologies with the engineer ing requirements of hazardous waste impoundments regulated under RCRA Subtitle C disposal facilities, which are used as the design basis for existing uranium byproduct material (i.e., tailings) impoundments.

Key Issue – All new impoundments shall a dopt the design and engineering standards referred to through 40 CFR 192.32(a)(1).

(3) Review the regulatory history.

Key Issue – NESHAP Subpart W continues to be the appropriate regulatory tool to implement the Administrator’s duty under the CAA for operating uranium mill tailings.

(4) Tailings impoundment technologies.

Key Issue – The emission limit for impoundme nts that existed as of December 15, 1989,

has been demonstrated to be both achievable and sufficient to limit risks to the levels that were found to protect public health with an ample margin of safety.

The requirement that impoundments opened after December 15, 1989, use either phased or continuous disposal technologies as appr opriate to ensure that public health is protected with an ample margin of safety, wh ich is consistent with section 112(d) of the 1990 Amendments of the CAA, which requires standards based on GACT.

(5) Radon measurement methods used to determin e compliance with the existing standards.

Key issue – The approved method (Method 115, 40 CFR 61, Appendix B) of monitoring Rn-222 to demonstrate compliance with the emission limit for impoundments that existed as of December 15, 1989, is still valid.

(6) Compare the 1989 risk assessment with cu rrent risk assessment approaches.

Key Issue – Adoption of a lower emission limit is not necessary to protect public health,

as the current limit has been shown to be protective of human health and the environment. Impact costs associated with the limit are considered to be acceptable.

5.1.1 Existing and Proposed Uranium Recovery Facilities

Sections 3.2, 3.3, and 3.4 describe the three types of uranium recovery f acilities: conventional mills, ISL facilities, and heap leach facilities. Each facility type is briefly described below.

Conventional Mills

Section 3 of this report presents a review of the existing and proposed uranium recovery facilities. As indicated, there are five conventio nal mills at various stages of licensing, with various capacities to receive ta ilings. Of these five conventional mills, only White Mesa is53 operational. Some of these were construc ted before December 15, 1989, and fall under the Subpart W monitoring requirement. Table 16 show s the current conventional mills with preDecember 15, 1989 conventional impoundments.

Table 16: Current Pre-December 15, 1989 Conventional Impoundments

Conventional

Mill Name Regulatory Status Pre-December 15, 1989 Impoundments Sweetwater Standby,* license expires November 2014 37 acres not full Shootaring Canyon Standby,* license extension May 2013 Only 7 acres of impoundment filled White Mesa Active, license expires March 2015 Cell 2 closed, Cell 3 almost full

* Standby means the period of time when a facility ma y not be accepting new tailings, but has not yet entered closure operations.

The White Mesa Mill (see Section 3.2.2) has one pre-1989 cell (Cell 3) that is authorized to accept tailings and is still open. Cell 2 is clos ed. Both cells are monitored for radon flux. The average radon flux for Cell 2 was calculated at 13.5 pCi/(m 2 -sec), while that at Cell 3 was 8.9 pCi/(m 2 -sec). The mill also uses an impoundment c onstructed before 1989 as an evaporation pond.

The Sweetwater Mill (see Section 3.2.1) has a 60 -acre tailings management area with a 37-acre tailings impoundment of which 28 acres are dry with an earthen cover. The remainder is covered by water. The radon flux from this impoundment is monitored yearly. The average flux (using Method 115) for the entire impoundment was 6.01 pCi/(m 2 -sec), including the water-covered area, which had an a ssumed flux of zero.

The Shootaring Canyon Mill (see Section 3.2.3) ha d plans for an upper and lower impoundment, but only the upper impoundment was constructe d. As the mill operated for approximately 30 days, only about 7 acres of tailings were deposited in the upper impoundment. These have a soil cover. The average radon flux from the cove red tailings was measured using Method 115 at 11.9 pCi/(m 2 -sec) in April 2010.

The Piñon Ridge Mill (see Section 3.2.4) is a perm itted conventional uranium recovery facility in Montrose County, Colorado. The facility has not been constructed; however, there are current activities at the site, including a pre-oper ational environmental monitoring program.

In-Situ Recovery

As discussed in Section 3.3, ISL was first c onducted in 1963 and soon expanded so that by the mid-1980s, a fair proportion of the recovered uranium was by ISL. Table 8shows the ISL

facilities in the United States that are currently operational. As previously discussed, the economics of ISL uranium recovery are conduciv e to lower grade deposits or deeply buried deposits that could not be economically rec overed with conventiona l open pit or underground mining. Thus, approximately 23 facilities ar e restarting, expanding, or planning for new operations (see Table 9).

Of particular importance to Subpa rt W are the impoundments that are an integral part of all ISL facilities. These impoundments are re quired to maintain the hydrosta tic gradient toward the leach54 field to minimize excursions referred to as “fla re,” a proportionality fact or designed to estimate the amount of aquifer water outsid e of the pore volume that has been impacted by lixiviant flow during the extraction phase. While these impoundme nts typically do not reach the size and scale of conventional tailings piles, they are an integral component of ISL, contain various amounts of radium, and can function as sources of radon gas. Section 3.3.1 provides the mathematical framework for estimating the quantity of radon being emitted from an impoundment. The subsequent discussion of Subpart W, incl uding a proposed standard for impoundments

constructed after Decembe r 15, 1989, will further evaluate this radon flux.

Heap Leach Facilities

The few commercial heap leach facilities established in the 1980s have been shut down. Recently, however, two heap leach facilities have been proposed: one in Wyoming (Sheep Mountain – Energy Fuels) and one in New Mexico (Grants Ridge, Uranium Energy Corporation) (see Section 3.4). If the price of uranium increases, then recovery of uranium from heap-leaching low-grade ores will become economically attractive and will likely lead to additional facilities. The question to be addressed from the standpoint of Subpart W is the radon flux released from the active heap leach pile. Also, once the uranium is removed from th e ore in the heap leach pile, the spent ore becomes a byproduct material much lik e the tailings, albeit not mobile. This spent

ore contains radium that releases radon. As the heap leach pile is constructed to a llow lixiviant to “trickle through” the pile, these same pathways could allow for radon release by diffusion out of the spent ore and then through the pile, which is addressed under Subpart W.

5.1.2 RCRA Comparison

Both alternative disposal methods presented in Subpart W (work pr actices) require that tailings impoundments constructed after December 15, 1989, meet the requirements of 40 CFR 192.32(a)(1). Tailings im poundments include surface impound ments, which are defined

in 40 CFR 260.10:

Surface impoundment or impoundment means a faci lity or part of a facility which is a natural topographic depr ession, man-made excavation, or diked area formed primarily of earthen materials (alt hough it may be lined with man-made materials), which is designed to hold an a ccumulation of liquid wastes or wastes containing free liquids, and which is not an injection well. Examples of surface impoundments are holding, storage, se ttling, and aeration pits, ponds, and lagoons.

The above definition encompasses conventional ta ilings ponds, ISL ponds, and heap leach piles.

The last is included as it is assumed that th e heap leach pile will be diked or otherwise constructed so as not to lose pr egnant liquor coming from the heap.

This being the case, 40 CFR 264.22 1(a) states that the impound ment shall be designed and constructed and installed to pr event any migration of wastes out of the impoundment to the adjacent subsurface soil or ground water or surfa ce water at any time duri ng the active life of the impoundment. Requirements of the liner syst em listed in 40 CFR 264.221(c) include:55 (1)(i)(A) A top liner designed a nd constructed of materials (e .g., a geomembrane) to prevent the migration of hazardous constituents into such liner during the active life.

(1)(i)(B) A composite bottom liner, consistin g of at least two components. The upper component must be designed and constructe d of materials (e.g., a geomembrane) to prevent the migration of hazardous constituen ts into this compone nt during the active life and post-closure care period. The lo wer component must be designed and

constructed of materials to minimize the mi gration of hazardous constituents if a breach in the upper component were to occur. The lower component must be

constructed of at least 3 ft (91 centimeters (cm)) of compacted soil material with a hydraulic conductivity of no more than 1×10

− 7 centimeters per second (cm/sec).

The regulation also requires a leachate collection system:

(2) The leachate collection and removal system between the liners, and immediately above the bottom composite liner in the case of multiple leachate collection and removal systems, is also a leak detection system. This leak detection system must be capable of detecting, collecting, and removi ng leaks of hazardous constituents at the earliest practicable time through all areas of the top liner lik ely to be exposed to waste or leachate during the active life and post-closure care period.

Other requirements for the design and ope ration of impoundments, given in 40 CFR 264 Subpart K, include construction specifications , slope requirements, and sump and removal requirements. The above requirements are impor tant to new uranium containment/impoundment systems because of the potential that water wi ll be used to limit the radon flux from a containment/impoundment. Thus, it is also importa nt to minimize the potential for ground water

or surface water contamination. Fo r conventional mill tailings im poundments, the work practices require a soil cover. With heap leach piles, the moisture in the heap would limit radon during operations, and after operations, a degree of moistu re would be required to ensure that the radon diffusion coefficient is kept low (see Section 5.4).

5.1.3 Regulatory History

Section 2.0 reviewed the regulator y history of Subpart W. This review indicates that NESHAP Subpart W continues to be the appropriate regula tory tool to implement the Administrator’s duty under the CAA. The following presents the use of GACT (see Section 5.3) in detail and

describes its use in conventional and ot her than conventional uranium recovery.

5.1.4 Tailings Impoundment Technologies

Sections 2.3.1 and 2.3.2 discuss tailings impoundmen t technologies. The two primary changes to the technology as it was previous ly practiced were first that owners and/or operators of conventional mill tailings impoundments must m eet the requirements of 40 CFR 192.32(a)(1) and second that they must adhere to one of th e two work practices prev iously discussed (for56 impoundments constructed after December 15, 1989) . Within these limits, tailings impoundment technologies have had no fundamental changes.

5.1.5 Radon Measurement Methods

As previously described, Subpart W defines two separate standards. The first states that existing sources (as of December 15, 1989) must ensure that emissions to the ambient air from an existing uranium mill tailings pile shall not exceed 20 pCi/(m 2 -sec) of Rn-222. To demonstrate compliance with this emission standard, facili ties are required to monitor emissions in accordance with Method 115 of 40 CFR 61, Appendix B, and file an annual report with EPA that shows the results of the complia nce monitoring (see Section 3.5). As pointed out in Appendix B, the focus of the monitoring was on the beaches, t ops, and sides of conventional piles. The radon flux from the water-covered portion of the tai lings pile was assumed to be zero. Although regulated under Subpart W, it is unclear how to monitor the radon flux off the surface of evaporation ponds at conventional mills, ISLs, or heap leach facilities. Since these ponds are considerably smaller than taili ngs impoundments, the solution was to specify that as long as the

water cover is 1 meter or more during the active life of the pond, no monitoring is necessary (see Section 3.3.1).

Section 3.3.1 also shows that, for evaporation pon ds at ISL facilities, the radon flux from the surface is a function of the wind sp eed and the concentration of ra dium in the water. Estimates using actual ISL data showed the contribution to the sites’ total radon rel ease to be less than 1% of the total. In any case, the radon flux can also be reduced by co-preci pitating the radium using barium chloride (BaCl 2 ) co-precipitation treatment to re duce the radium concentration.

For impoundments constructed on or after D ecember 15, 1989, monitoring is not required. Rather, Subpart W requires that these impoundme nts comply with one of two work practice standards: the first pr actice limits the size of the impoundment to 40 acres or less, which limits the radon source, while the second practice of continuous disposal does not allow uncovered tailings to accumulate in large quantities, which also limits radon emissions.

For evaporation ponds or holding ponds as in the pre-December 15, 1989, case, a 1-meter cover

of water should be sufficient to limit the radon flux to the atmosphere (see Section 3.3.1). Thus, the proposed GACT is that these impoundments m eet the design and construction requirements of 40 CFR 192.32(a)(1), with no si ze or area restriction, and th at during the active life of the pond at least 1 meter of liquid be maintained in the pond.

The last facility is the potential heap leach pile. Subpart W applies to the material in the pile as byproduct material is being generate d. Considering a small section of the pile as the leach (acid or base) solubilizes the uranium, the material left is byproduct mate rial. The result is a material similar to tailings and the heap is also wet. It is assumed that if the moisture content is greater than 30%, the heap is not dewatered. As long as the heap is not dewatered, the radon diffusion

coefficient is such that minimal radon will escape the heap leach pile.57 Heap Leach Radon Flux

A possible source of radon from a heap leach pile is from the surface of the pile. Assuming that the heap pile is more than 1 or 2 meters th ick, the radon flux from this configuration can be estimated from the following formula (NRC 1984):

J = 10 4 R ρ E ඥ ߣ ܦ
௘ ) 5-1 (

Where J = radon flux (pCi/(m 2 -sec))

10 4 = units conversion (cm 2 /m 2 )

R = specific activity of radium (pCi/g)

ρ = dry bulk density of material (1.8 g/cc)

E = emanation coefficient

λ = radon decay constant (2.11×10 -6 sec -1 )

D e = radon diffusion coefficient (cm 2 /sec)

= D 0 p exp[-6 m p -6 m 14 p ] (5-2)

D 0 = radon diffusion coefficient in air (0.11 cm 2 /sec)

m = moisture saturation fraction p = total porosity

The above empirical expression for the radon diff usion coefficient was developed by Rogers and Nielson (1991), based on 1,073 diffusion coeffici ent measurements on natural soils. Figure 13

shows that the diffusion coefficient calculated using the empirical expression agrees well with the measured data points over the whole range of moisture saturation at which diffusion

coefficient measurements were made.

Source: Rogers and Nielson 1991, as reported in Li and Chen 1994 Figure 13: Diffusion Coefficient as a Function of

Moisture Saturation58 Figure 13 also demonstrates that as the mois ture increases, the radon diffusion coefficient decreases significantly. This is because radon diffuses 10,000 times mo re slowly in water than it does in air (Drago 1998, as reported in Brown 2010). Therefore, adding moisture to the radium-containing material (whether it be a tailin gs pile or a heap pile) would decrease the diffusion coefficient, thereby increasing the time it takes for radon to diffuse out of the material and allowing more radon to decay before it can be released. As Figure 13 shows, the decrease in

the radon diffusion coefficient can be significant, especially at high moisture levels.

However, in addition to the radon diffusion co efficient, the radon emanation coefficient is sensitive to the amount of moisture present. When a radium atom decays, one of three things can happen to the resulting radon atom: (1) it may trav el a short distance and remain embedded in the same grain, (2) it can travel across a pore space and become embedded in an adjacent grain, or (3) it is released into a pore space. The frac tion of radon atoms released into the pore space is termed the “radon emanation coefficient” (Schum ann 1993). As soil moisture increases, it affects the emanation coefficient by surrounding the soil grai ns with a thin film of water, which slows radon atoms as they are ejected from the soil gr ain, increasing the likeli hood that the radon atom will remain in the pore space. Research by Sun and Furbish (1995) describes this relationship

between moisture saturation and the radon emanation rate:

The greater the moisture saturation is , the greater the possible radon emanation

rate is. With moisture co ntents from 10% up to 30%, the recoil emanation rates quickly reach the emanation rate of the saturated condition. As the moisture reaches 30%, a universal thin film on the por e surface is formed. This thin film is sufficient to stop the recoil radon from embedding into another part of the pore

wall.

Figure 14 shows that the radon emanation coefficien t can vary considerably for different tailings piles. Figure 14 also agrees with Sun and Furb ish (1995) in that it s hows that the emanation

coefficient tends to level off when the moistu re saturation level is above approximately 30%.59 Source: NRC 1984 Figure 14: Emanation Coefficien t as a Function of Moisture

Content and Moisture Saturation

In conclusion, a moisture saturation level of up to about 30% tends to increase the radon

emanation coefficient and decrease the radon diffus ion coefficient, such th at the amount of radon released from the pile could increase with increasing moisture. Above about 30% moisture saturation, the radon emanation coefficient is un changed by increasing moisture, while the radon

diffusion coefficient continues to decrease. Figure 15 shows the total effect of moisture on the radon flux. Equation 5-1 was used to develop Fi gure 15, along with the Rogers and Nielson (1991) empirical equation for the diffusion coe fficient, an approximation of the Vitro Sand emanation coefficient from Figure 14, and a poros ity of 0.39. Figure 15 does not show the radon flux values, since they would vary depending on th e radium concentration and would not affect the shape of the curve.60 Figure 15: Radon Flux as a Func tion of Moisture Saturation and

Moisture Content

Figure 15 shows that the radon flux starts low and increases as th e moisture saturation increases

due to the emanation coefficient. At between 20% and 30% moisture saturation, the flux reaches a peak that is about 21⁄2 times the flux at zero mo isture, after which the diffusion coefficient takes control and the flux decreases. Figure 15 is consiste nt with the results reported by Hosoda et al. (2007) in their study of the effect of moisture on the emanation of radon and thoron gases from weathered granite soil:

A sporadic increase in the radon and thor on exhalation rates was caused by the increase in the moisture content up to 8% [27% moisture saturation] . However, the exhalation rates showed a decreasing tendency with the increase in moisture
content over 8%..., both measured and calculated radon exhalation rates had

similar trends with an increase in the moisture content in the soil.

The final point from Figure 15 is that the radon fl ux with a moisture content of 70% or greater is less than the flux at zero moisture, and that wi th a porosity of 0.39, 70% moisture saturation is equivalent to 27% moisture by weight. Thus, 30% moisture by weight would result in a radon flux significantly below the zero moisture flux.

5.1.6 Risk Assessment

Section 4.4 presents the results of a risk assessm ent performed for seven actual uranium recovery sites plus two generic uranium recovery sites. This risk assessment used the CAP88 Version 3.0 analytical computer model, which, as described in Section 4.0, evolved from and differs from the

models used for the 1989 risk assessment (i.e., AIRDOS-EPA, RADRISK, and DARTAB). Additionally, this assessment used the latest radon dose and risk coefficients (i.e., millirem61 (mrem)/picocurie (pCi) and LCF/pCi) from FGR 13. Both the 1989 assessment and this assessment used site-specific meteorological da ta. This assessment used 2000 census data, updated to 2010, whereas the 1989 assessment used 1983 data. Finally, as stated above, this

assessment used actual historical radon releases from the uranium recovery sites, whereas because of the lack of site-specific data, the 1989 assessment assumed a radon release rate based on 1 pCi/(m 2 -sec) Rn-222 emitted per pCi/g Ra-226 during both the operating, standby, drying, and/or disposal phase , and either 20 pCi/(m 2 -sec) or the design fl ux (if known) during the post-disposal phase.

Section 4.4 presents the doses and risks calcu lated by the current risk assessment, and

Section 4.5summarizes them. Add itional information on the current risk assessment appears in

SC&A 2011.

5.2 Uranium Recovery Source Categories

The preceding items and key issues are the basi s for categorizing the major uranium recovery

methods that will lead to methods of reduc ing radon emissions. The next section, which addresses the GACT standard, further discusses th e applicability of the control measures. The following source categories represent a logical breakdown of the current uranium recovery industry:

Conventional Impoundments – Conventional impoundments are engineered structures for storage and eventual permanent disposal of the fine-grained waste from mining and milling operations (i.e., tailings). All conventional uranium recovery mills have one or more conventional impoundments. Table 3 shows conve ntional uranium milling facilities that are either built or licensed. This category will also include future conventi onal milling facilities.

Nonconventional Impoundments – At nonconventional tailings impoundments, tailings (byproduct material) are contained in ponds a nd covered by liquids. These impoundments are normally called “evaporation ponds” or “holding ponds.” Nonetheless, they contain byproduct material and, as shown in Section 3.3.1, can generate radon gas. This category is usually associated with ISL facilities (i.e., process waste water resulting from ISL operations (see Section 3.3)), but can also be associated with co nventional facilities or heap leach facilities. While these ponds do not meet the work practices fo r conventional mills, they still must meet the requirements of 40 CFR 192.32(a)(1).

Heap Leach Piles – While no heap leach facilities are currently operating in the United States, at least one potential operation is exp ected to go forward (see Section 3.4). Heap leach piles contain byproduct material, which is the residue of the ope ration. That is, as the lixiviant mobilizes the uranium, the remaining part of the ore becomes byproduct. As stated above, the design and operation of the heap leach is expected to follow the requirements of 40 CFR 192.32(a)(1).

5.3 The GACT Standard

Section 112(d) of the CAA requires EPA to esta blish NESHAPs for both major and area sources

of HAPs that are listed fo r regulation under CAA section 112(c). Section 112(c) lists62 radionuclides, including radon, as a HAP, while section 112(a) defines two types of HAP sources: major sources and area sources. Depending on whether the source is a major or area source, section 112(d) prescrib es standards for regulation of emissions of HAP. A “major source,” other than for radionuclide s, is defined as any stationary source or group of stationary sources located within a contiguous area and under common control that emits or has the potential to emit, in the aggreg ate, 10 tons per year or more of any HAP. For radionuclides, major source shall have the meaning specified by the Administrator by rule . An area source is a stationary source that is not a major source.

The regulation of HAPs at major sources is dict ated by the use of MACT . Section 112(d) defines MACT as the maximum degree of reduction in HAP emissions that the Administrator determines is achievable, considering the cost of achievi ng the reduction and any non-air-quality health and environmental impacts and energy requirements. W ith respect to area s ources, section 112(d)(5) states that, in lieu of promulgating a MACT sta ndard, the Administrator may elect to promulgate standards that provide for the use of GACT or management pract ices to reduce HAP emissions.

In 2000, EPA provided guidance to clarify how to apply the major source threshold for HAPs as defined in section 112(b) of the CAA Amendmen ts of 1990. The guidance stated how to apply the major source threshold specifically for radionuclides:

There have been some questions about determining the major source threshold for sources of radionuclides. Section 112(a)(1) allows the Administrator to establish different criteria for determining what constitutes a major source of

radionuclides since radionuclides emissions are not measured in units of tons. This, however, would not preclude a known radionuclide emitter that is collocated with other HAP-emitting activ ities at a plant site from being considered a major source due to the mo re common, weight-based threshold. The July 16, 1992, source category list noti ce did not include any sources of

radionuclides because no source met the weight-based majo r source threshold, and the Agency had not defined different cr iteria. At the cu rrent time, there remain no listed major source cate gories of radionuclide emissions. [EPA 2000b]

Based on this guidance, radon emissions from ur anium recovery facility tailings impoundments are not a major source, and therefore, they ar e area sources for which the GACT standard is applicable. Unlike MACT, the meaning of GACT, or what is “generally available” is not defined in the act. However, section 112(d)(5) of th e CAA Amendments for 1990 authorizes EPA to:

Promulgate standards or requirements applicable to [area] sources...which provide for the use of generally avail able control technologies or management practices by such sources to reduce emissions of hazardous air pollutants.

The Senate report on the legislation (U.S. Se nate 1989) provides additional information on

GACT and describes it as:

...methods, practices and t echniques which are commercially available and appropriate for application by the sources in the category considering economic63 impacts and the technical c apabilities of the forms to operate and maintain the emissions control systems.

Determining what constitutes GACT involves considering the control technologies and management practices that are generally available to the area sources in the source category.

Also considered are the standard s applicable to major sources in the same industrial sector to

determine if the control technol ogies and management practices are transferable and generally available to area sources. In appropriate circum stances, technologies and practices at area and major sources in similar categories are also re viewed to determine whether such technologies and practices can be considered generally availabl e for the area source cate gory at issue. Finally, as noted above, in determining GACT for a pa rticular area source category, the costs and economic impacts of available control technologi es and management practices on that category

are considered.

Thus, as presented above, “Promulgate standard s or requirements ... ” does not limit EPA to strict “standard setting” in or der to provide for the use of GACT. Rather, it allows EPA to promulgate at least two types of rules: rules that set emission levels based on specific controls or management practices (this is an alogous to the MACT standard se tting), and rules that establish permitting or other regulatory processes that result in the identification and application of GACT

standards.

5.4 Uranium Recovery Categories and GACT

For conventional impoundments, the 1989 promul gation of Subpart W contained two work practice standards, phased dispos al and continuous disposal (s ee Section 2.0, page 7). The work practice standards limit the size and number of the impoundments at a uranium recovery facility

in order to limit radon emissions. The standards cannot be applied to a single pile that is larger than 40 acres (for phased disposal) or 10 uncove red acres (for continuous disposal). This approach was taken in recogni tion that the radon emissions fr om these impoundments could be greater if the piles were left dry and un covered. The 1989 Subpart W also included the requirements in 40 CFR 192.32(a), which include design and construction requirements for the impoundments as well as requirements fo r preventing and mitigating ground water

contamination.

As discussed earlier, it is no longe r believed that a distinction need s to be made for conventional impoundments based on the date when they we re design and/or constructed. The existing impoundments at both the Shootaring Canyon (S ection 3.2.3) and Sweetwater (Section 3.2.1)

facilities can meet the work practice standards in the current Subpart W regulation. Impoundments at both these facilities have an area of less than 40 acres and are synthetically lined as required in 40 CFR 192.32(a). Also, the ex isting Cell 3 at the White Mesa mill will be closed in 2012 and replaced w ith impoundments that meet the phased disposal work practice standard (Section 3.2.2). Therefor e, there is no reason not to a pply the work practice standards required for impoundments designed or constructed after December 15, 1989, to these older impoundments. By incorporating these impoundmen ts under the work practice standards, the requirement of radon flux testing is no longer needed and will be eliminated.64 For the proposed GACT, the requirements of 40 CFR 192.32(a) as they pert ain to the Subpart W standards were evaluated. Liner requirements in use for the permitting of hazardous waste land disposal units under RCRA are containe d in 40 CFR 264.221. Since 40 CFR 192.32(a)(1) references 40 CFR 264.221, it is the only requir ement necessary for Subpart W, as the RCRA requirements are effective methods of containing tailings and protecti ng ground water while also limiting radon emissions. The regulation in 40 CF R 264.221 contains safeguards to allow for the placement of tailings and also provides for an earl y warning system in the event of a leak in the liner system. Therefore, the proposed GACT for conventional impoundme nts retains the two work practice standards and the requirements of 40 CFR 192.32(a)(1 ), because they have proven to be effective methods for limiting radon emissions while also protecting ground water. The NRC considers the requirements of 40 CFR 192.32(a) in its review during the licensing process.

For nonconventional impoundments, where tailings (byproduct material) are contained in ponds and covered by liquids, a new GAC T is proposed. These facilities, called “evaporation ponds” or “holding ponds,” also must meet the require ments of 40 CFR 192.32(a)(1). Specifically, these are the design and operating requirements for the impoundments. Because of the general experience that a depth of great er than 1 meter of liquid esse ntially reduces the radon flux of ponds to negligible levels, no monitoring is requir ed for this type of impoundment. Given these factors, the following GACT is proposed:

Nonconventional impoundments meet the design and construction requirements of 40 CFR 192.32(a)(1), with no size/area restriction, a nd during the active life of the pond, at least 1 meter of liqui d be maintained in the pond.

For the last category, heap leach piles, an approach similar to that for nonconventional impoundments is proposed. As previously noted, these facilities contain byproduct material, which is the residue of the ope ration. That is, as the lixiviant mobilizes the uranium, the remaining part of the ore becomes byproduct mate rial, which is regulated under Subpart W. As for nonconventional impoundments, the design and opera tion of the heap leach pile is expected to follow the requirements of 40 CFR 192.32(a)(1). This also will prevent the loss of pregnant liquor (lixiviant with dissolved uran ium) from spillage or leakage.

The byproduct material that makes up the volume of the spent heap leach p ile is typically wet. As Figure 15 shows, as material goes from dr y to wet the radon flux first increases before it decreases (the reasons for this are discussed in Section 5.1.5). While it is impossible to maintain a completely wet state, it is possible to maintain a sufficient percentage of moisture content to meet a goal that the radon flux in the wetted mate rial is below what the flux would be if the material was dry. This percentage is related to th e state or material being “dewatered.” By way of definition, 40 CFR 61.251(c) states:

Dewatered means to remove the water from recently produced tailings by mechanical or evaporative methods such t hat the water content of the tailings

does not exceed 30 percent by weight

.

Thus, the proposed GACT for heap leach p iles is that, in addition to meeting 40 CFR 192.32(a)(1), operating heap leach piles mu st maintain a moisture content greater than65 30% (equivalent to about 70% to 80% moisture saturation, as described in Section 5.1.5). This would, as indicated, ensure that the radon flux from th e surface of the pile is quite low, i.e., at or

below what the flux would be if th e material in the pile was dry.

Since the purpose of this GACT is to control the radon emissions , it may not be critical to

maintain the 30% moisture content in the lower leve ls/lifts of the pile. The reason for this is twofold; first, radon generated in the lower levels would have to travel further in the pile before it would escape to the atmosphere, thereby giving it more time to decay within the pile, and second, radon from the lower layers will be slowed due to the 30% moisture content in the upper levels. Additionally, if inter-lift liners are provided when the pile is composed of multiple lifts,

the inter-lift liner would act as a barrier to radon from the lower lifts, and thus mitigate the need

for those lower lifts to maintain the 30% mois ture content. On the other hand, because radon emission do not stop when active uranium leaching has ceased, it will be necessary to continue wetting the pile to maintain the 30% moisture co ntent until a final reclamation cover (including a radon barrier layer) has been constructed over the pile.

5.5 Other Issues

During the review of Subpart W, several addition al issues were identifi ed. These are identified

and discussed in this section.

5.5.1 Extending Monitoring Requirements

In reviewing Subpart W, EPA examined whet her radon monitoring should be extended to all impoundments constructed and operated since 1989 so that the monitoring requirement would apply to all impoundments containing uranium byproduct material (i.e., tailings). EPA also reviewed how this requirement would apply to facilities where Method 115 is not applicable, such as at impoundments totally covered by liquids. As the rule currently exists, only pre-1989 conventional tailings impoundments are required to monitor for radon emissions, the requirement being an average flux rate of not more than 20 pCi/(m 2 -sec). This is because, at the time of promulgation of the 1989 rule, EPA stated that the proposed work practic e standards would be effective in reducing radon emissions from operating impoundments. Since the work practice standards could not be applied to pre-1989 facilities, and since EP A determined that it is not feasible to prescribe an emissions standard for radon emissions from a tailings impoundment (54 FR 9644 (FR 1989a)), the improved work pract ice standards would limit radon emissions by limiting the amount of tailings exposed.

Thus, it is not necessary to require radon monito ring at facilities constr ucted after the current Subpart W was promulgated (i.e., December 15, 1989) . With respect to tailings and the amount of water used to cover them, the work practi ce standards (now proposed as GACTs) are also protective in preventing exce ss radon emissions. Further, for nonconventional impoundments, where there is no applicable radon monitori ng method, the standing liquid requirement will effectively prevent all radon emissions from holding or evaporation ponds.66 5.5.2 Clarification of the Term “Operation”

As currently written, 40 CFR 61.251(e) defines th e operational period of a tailings impoundment. It states that “operation” means that an impound ment is being used for the continuing placement of new tailings or is in standby status for such placement [which means that as long as the facility has generated byproduct material at so me point and placed it in an impoundment, it is subject to the requirements of Subpart W]. An impoundment is in operation from the day that tailings are first placed in the impoundment until the day that final closure begins.

There has been some confusion over this defini tion. For example, a uranium mill announced that it was closing a pre-December 15, 1989, impoundment. Before initiating closure, however, it stated that it would keep the impoundment open to dispose of material generated by other closure activities at the site that contained byproduct mate rial (liners, deconstruc tion material, etc) but not “new tailings.” The company argued that since it was not disposing of new tailings the impoundment was no longer subject to Subpart W. We disagree with this interpretation. While it may be true that the company was no longer disp osing of new tailings in the impoundment, it has not begun closure activities; ther efore, the impoundment is still open to disposal of byproduct material that emits radon and continues to be subj ect to all applicable Su bpart W requirements.

To prevent future confusion, we are proposing to amend the definition of “operation” in the Subpart W definitions at 40 CFR 61.251 as follows:

Operation. Operation means that an impound ment is being used for the continued placement of uranium byproduct material or tailings or is in standby status for such placement. An impoundment is in operation from the day that uranium byproduct materials or tailings are first placed in the impoundment until the day that final closure begins.

5.5.3 Clarification of the Term “Standby”

In the past, there has been confusion as to wh ether the requirements of Subpart W apply to a uranium recovery facility that is in “sta ndby” mode. Although not formally defined in Subpart W, “standby” is commonly taken to be the period of time when a facility may not be accepting new tailings, but has not yet entered cl osure operations. This period usually takes place when the price of uranium is such that it may not be cost effective for the facility to continue operations, and yet the facility fully intends to op erate once the price of uranium rises to a point where it is cost effective for the facility to re-establish operations. As shown in Table 3, the Sweetwater and Shootaring Canyon mills are curr ently in standby. While in standby, a uranium recovery facility can ch ange its license from an operating license to a possession only license, thereby reducing its regulato ry obligations (and costs).

The addition of the following definition of “closure” into the Subpart W definitions at

40 CFR 61.251 would eliminate confusion:

Standby. Standby means the period of time th at a facility may not be accepting new tailings, but has not yet entered closure operations.67 5.5.4 The Role of Weather Events

In the past, uranium recovery f acilities have been located in the western regions of the United States. In these western regions , the annual average precipitati on (see Figure 16) falling on the impoundment is less than the annual average eva poration (see Figure 17) from the impoundment. Also, these facilities are located away from regi ons of the country where extreme rainfall events (e.g., hurricanes or flooding) could jeopardize th e structural integrity of the impoundment, although there is a potentia l for these facilities to be affect ed by flash floods, tornadoes, etc. However, recent uranium exploration in the Unite d States shows the potential to move eastward, into more climatologically temperate regions of the country. South central Virginia is now being considered for a conventional uranium mill (e.g., the Coles Hills, see Table 4). To determine whether additional measures would be needed for impoundments operating in areas where precipita tion exceeds evaporation, a review of the existing requirements

was necessary.

Figure 16: U.S. Average Annual Precipitation68 Figure 17: U.S. Mean Annual Evaporation

Subpart W requires owners and operators of uranium tailings impoundments to follow the requirements of 40 CFR 192.32(a). That particul ar regulation references the RCRA surface impoundment design and operations require ments of 40 CFR 264.221. At 40 CFR 264.221(g) and (h) are requirements that can be used to en sure proper operation of tailings impoundments. Section 264.221(g) states that impoundments must be designe d, constructed, maintained, and operated to prevent overtopping resulting from normal or abnormal operations; overfilling; wind and rain action; rainfall; run-on; malfunctions of level controllers, alarms and other equipment; or human error. Section 264.221(h) states that impoundments must have di kes that are designed, constructed, and maintained with sufficient structur al integrity to prevent massive dike failure. In ensuring structural integrity, it must not be pres umed that the liner system will function without leakage during the active life of the unit.

Uranium recovery facilities are alre ady operating under th e requirements of 40 CFR 192.32(a)(1), including compliance with 40 CFR 264.221(g) and (h), which will provide protection against the weather events likely to occur in the eastern United States.

6.0 ECONOMIC IMPACTS ASSOCIATED WI TH REVISION/MODIFICATION OF

THE SUBPART W STANDARD

This section contains the following economic imp act analyses necessary to support any potential

revision of the S ubpart W NESHAP:

 Section 6.1 provides a review and summary of the origin al 1989 economic assessment and supporting documents.

 The baseline economic costs for developmen t of new conventional mills and ISL and69 heap leach facilities are devel oped and presented in Section 6.2.

 Section 6.3 presents the anticip ated industry costs versus environmental and public health benefits to be derived from each of the four proposed GACT standards.

 Finally, Section 6.4 provides demographic data regarding the racial and socioeconomic composition of the populations surroundi ng uranium recove ry facilities.

To assess the economic impacts of potential revi sions to the Subpart W NESHAP, capital costs (including equipment costs), labor costs, taxes, etc., were obtain ed from actual recent cost estimates that have been prepared for compan ies planning to design, de velop, construct, and operate uranium recovery facilities. For ISL facilit ies, two recent cost estimates were used as the basis for this analysis, while for conventional mills and heap leach facilities, a single cost estimate was used for each type of facility. Other necessary data, su ch as a discount rate, borrowing, and interest rates, were as sumed, as described in Section 6.2.

Where feasible and appropriate, the economic models and recommendations from EPA’s “Guidelines for Preparing Economic Analyses” (EPA 2010) were followed in assessing these economic impacts.

The cost and economic impact estimates descri bed in Section 6.2 and 6.3 are based on industry data compiled in 2010-2011. Therefore, some of the analytical input values would differ somewhat if they were updated to reflect the latest information available. For example, the current long-term market price of uranium is approximately 17 percent lower than the $65

estimate that is used in the analysis (Cameco, 2013). The uraniu m mining industry is currently experiencing a volatile period resulting from the aftereffects of the Fukushima nuclear disaster. In particular, uranium demand has suffered from nearly all of Japan’s workable reactors remaining offline since the March 2011 earthquake and tsunami triggered multiple meltdowns at the Fukushima Dai-ichi plant. Given the atypical post-Fukushimauranium market situation of the last couple of years and the prospects for a return to more normal market activity in the midterm future, 7 we have decided not to update the analysis to incorporate the latest industry data. The results of the analyses descri bed in this section are judged to be realistic estimates of the mid- to long-term impacts of the proposed Subpart W NESHAP.

6.1 1989 Economic Assessment

When Subpart W was promulgated in 1989, EPA perf ormed both an analysis of the standard’s

benefits and cost and an evaluation of its econom ic impacts. Those analyses appear in the 1989 BID, Volume 3, Sections 4.4 and 4.5 (EPA 1989). This section briefly summarizes the Subpart W economic assessments performed in 1989.

7 These prospects include: the conclusion of the U. S.-Russia program that annually removes 24 million pounds of ex-military highly enriched uranium from the market via down-blending for use as U.S. nuclear fuel; the 60 nuclear power plants that are curr ently under construction throughout the world; efforts to reduce climate change emissions; and expectations that Japan will sl owly begin restarting its 50 nuclear plants.70 In these 1989 assessments, EPA evaluated the benef its and costs associated with three separate

decisions. The first decision concerned a limit on allowable radon emissions after closure. The options evaluated includ ed reducing radon emissions from the 20 pCi/(m 2 -sec) limit to 6 pCi/(m 2 -sec) and 2 pCi/(m 2 -sec).

The second decision that EPA investigated was the means by which the emissions from active mills could be reduced to the 20 pCi/(m 2 -sec) limit while operations continue. Emissions could be reduced by applying earth and water covers to portions of the dry areas of the tailings piles, which could reduce average radon emissions for the entire site to the 20 pCi/(m 2 -sec) limit.

While the first two decisions were focused on taili ngs piles that existed at the time the standard was promulgated, the third concerned future ta ilings impoundments. EPA evaluated alternative work practices for the control of radon emissions from operating mills in the future. Options investigated include the replacement of the traditional single-cell impoundment (i.e., the 1989 baseline) with phased disposal or continuous disposal impoundments.

6.1.1 Reducing Post-Closure Radon Emissions from 20 pCi/(m 2 -sec)

The 1989 BID estimated the total annual tailings piles radon emissions for standards of 20, 6, and 2 pCi/(m 2 -sec) and calculated the cance rs that could result from those emissions. It found that over a 100-year anal ysis period, the 6 pCi/(m 2 -sec) option could lower local and regional risks by 3.6 cancers, while the incr emental benefit of lowering the allowable flux rate from 6 to 2 pCi/(m 2 -sec) was estimated at 1.0 cancer.

The increased costs associated with reducing the allowable flux rate from 20 to 6 pCi/(m 2 -sec)
were estimated to be between $113 and $180 million (1988$) ($205 and $327 million (2011$)), while attainment of a 2 pCi/(m 2 -sec) flux rate was estimated to result in added costs of $216 to $345 million (1988$) ($393 to $627 million (2011$)).

The 1989 BID does not make any statement regard ing the monetized value of reduced cancer risks. Nor does it explicitly weigh the costs and benefits of the alterna tive standards. As the following excerpt from the preamble to the standa rd shows, for tailings piles at operating mills, EPA’s decision was based on the very low risks associated with 20 pCi/(m 2 -sec), rather than on a comparison of the benefits versus the cost s of the alternative emission standards:

... the risks from current emissions are very low. A NE SHAP requiring that emissions from operating mill tailings p iles limit their emissions to no more than 20 pCi/(m 2 -sec) represents current emissions. EPA has determined that the risks are low enough that it is unnecessary to reduce the already low risks from the tailings piles further. [FR 1989a, page 51680]

While for tailings impoundments at inactive mills, the preamble presented a quantitative cost-benefit comparison as ju stification for maintaining the radon emission level at 20 pCi/(m 2 -sec):71 EPA examined these small reductions in incidence and maximum individual risk and the relatively large costs of achieving Alternative II [6 pCi/(m 2 -s)] , $158 million capital coat and $33 million in annualized costs and determined that

Alternative I [20 pCi/(m 2 -s)] protects public health with an ample margin of safety. [FR 1989a, page 51682]

6.1.2 Reducing Radon Emissions During Operation of Existing Mills

The 1989 BID estimated the reduction in total risk that could be obtained by reducing radon emissions from active mills operating at that time to 20 pCi/(m 2 -sec) through the application of an earthen cover and/or by keeping the tailings wet. The 1989 BID, Table 4-41, reported the risk

reduction to be 0.17 fatal cancers for all active mills over their assumed 15-year operational life.

The 1989 BID, Table 4-42B, reported that the co st for providing the earthen covers and for keeping the tailings wet over the 15-year ope rating period was estimated to be $13.166 million (1988$) ($23.94 million in 2011$).

The 1989 BID does not make any statement regard ing the monetized value of reduced cancer risks. Nor does it explicitly weigh the costs a nd benefits of the alte rnative standards. EPA

nonetheless decided that without these standards the risks were too high, as the following segment from the preamble to the standard indicates:

... EPA recognizes that the risks from mill ta ilings piles can increase dramatically if they are allowed to dry and remain unc overed. An example of how high the risks can rise if the piles are dry and unco vered can be seen in the proposed rule, 54 FR 9645. That analysis assumed that the piles were dry and uncovered and the risks were as high as 3×10 -2 with 1.6 fatal cancers per year. Therefore, EPA is promulgating a standard that will lim it radon emissions to an average of 20 pCi/m 2 -s. This rule will have the practical e ffect of requiring the mill operators to keep their piles wet or covered. ... [FR 1989a, page 51680]

6.1.3 Promulgating a Work Practice Standard for Future Tailings Impoundments

Section 4.4.3.1 of the 1989 BID provides the fo llowing explanations of the phased and continuous disposal options:

Phased Disposal

The first alternative work practice whic h is evaluated for model new tailings impoundments is phased disposal. In phased or multiple cell disposal, the tailings impoundment area is partitioned into cells which are used independently of other cells. After a cell has been filled, it can be dewatered and covered, and another cell used. Tailings are pumped to one initial cell until it is full. Tailings are then pumped to a newly constructed second ce ll and the former cell is dewatered and then left to dry. After the first cell dries, it is covered with earth obtained from the construction of a third cell. This proce ss is continued sequentially. This system72 minimizes emissions at any given time since a cell can be covered after use without interfering with operations as opposed to the case of a single cell.

Phased disposal is effective in reduci ng radon-222 emissions since tailings are initially covered with water and finally with earth. Only during a drying-out period of about 5 years for each cell are there any [significant] radon-222 emissions from the relati vely small area. During mill standby periods, a water cover could be maintained on the opera tional cell. For exten ded standby periods,

the cell could be dewatere d and a dirt cover applied.

Continuous Disposal

The second alternative work practice, c ontinuous disposal, is based on the fact that water can be removed from the ta ilings slurry prior to disposal. The relatively dry dewatered (25 to 30% moisture [by weight] ) tailings can then be dumped and covered with soil almost immediately. No extended drying phase is required, and therefore very little additi onal work would be required during final closure. Additionally, ground wa ter problems are minimized.

To implement a dewatering system would introduce complications in terms of planning, design, and modification of curre nt designs. Acid-based leaching processes do not generally recycle water, and additional holding ponds with ancillary piping and pumping systems w ould be required to handle the liquid removed from the tailings. Using trucks or conveyor systems to transport the tailings to disposal areas might also be more costly than slurry pumping. Thus, although tailings are more easily managed after dewatering, this practice would have to be carefully considered on a site-specific basis.

Various filtering systems such as rota ry vacuum and belt fil ters are available and could be adapted to a tailings dewateri ng system. Experimental studies would probably be required for a specific ore to determine the filter media and dewatering properties of the sand and slime fractions. Modifications to the typical mill ore grinding circuit may be required to allow efficient dewatering and to prevent filter plugging or blinding. Corro sion-resistant materials would be required in any tailings dewatering system due to the highly corrosive solutions

which must be handled. ...

The committed fatal cancer risk 8 from the operation of model ba seline (single-cell), phased disposal, and continuous dispos al impoundments, as determined by the 1989 BID, is shown in Table 17. Table 17 shows the following:

[during] the operational period the risk of canc er is reduced, relative to the single cell baseline, by 0.129 if phased disp osal is adopted and by 0.195 if the continuous single cell method is used. The risk reduction associated with using the continuous single cel l relative to the phased approach is 0.066. In the post-operational phase, phased disposal rais es the risk by 0.012 relative to the

8 “Committed fatal cancer risk” is the likeliness that an individual will develop and die from cancer at some time in the future due to their current exposure to radiation. “Committed fatal cancer risk” is sometimes referred to as “latent cancer fatality risk.”73 baseline, while the continuous single ce ll approach lowers it by 0.017 relative to the baseline and by 0.028 rela tive to phased disposal. [EPA 1989, Section 4.4.3.3]

Table 17: Radon Risk Resulting from Alternative Work Practices (Committed Cancers)

Baseline (Single Cell) Phased Disposal Continuous Disposal Operational Period (0 to 20 years) 0.282 0.153 0.087

Post-Operations (21 to 100 years) 0.264 0.276 0.247

Total 0.546 0.429 0.334

Source: EPA 1989, Table 4-45

Concerning the cost to implement the work prac tices, the 1989 BID indica tes the following:

the phased ... disposal impoundment is the most expensive design ($54.02 million [1988$] ), while the single ce ll ... impoundment ($36.55 million [1988$] ) is the least expensive. Costs for the con tinuous single cell design ($40.82 million [1988$] ) are only slightly more than t hose of the single cell impoundment, although the uncertainties surrounding the te chnology used in this design are the largest . [EPA 1989, Section 4.4.3.4]

The 1989 BID does not make any statement regard ing the monetized value of reduced cancer risks. Nor does it explicitly wei gh the costs and benefits of the al ternative standards. However, as the following excerpt from the preamble to the standard shows, EPA was concerned about the uncertainty of the benefits and costs analysis that had been performed for this portion of the regulation. Ultimately, the Agency based its deci sion on the small cost to implement the work practices, rather than on weighing the benefits vers us the costs:

The uncertainty arises because it assumes a steady state industr y over time. If the uranium market once again booms there woul d be increased risks associated with

Alternative I [one large impoundment (i.e., baseline)] . If the industry then experienced another economic downturn, the co sts of Alternative I would increase because of the economic waste that occurs when a large impoundment is constructed and not filled. The risks can al so increase if a company goes bankrupt and cannot afford the increased costs of closing a large impo undment and the pile sits uncovered emitting radon. The risks can also increase if many new piles are constructed, creating the potential for the population and individual risks to be higher than EPA has calculated.

These uncertainties significantly affect the accuracy of the [benefits and costs] analysis and given the small cost of going to Alternatives II [phased disposal] and

III [continuous disposal] , EPA has determined that in order to protect the public74 with an ample margin of safety, both now and in the future, new mill tailings impoundments must use phased or continuous disposal. [FR 1989a, page 51680]

6.1.4 Economic Impacts

To determine the economic impacts of the proposed Subpart W on the uranium production industry, the 1989 BID evaluated two extreme cases; in the first, it was assumed that “no portion of the cost of the regulation can be passed on to the purchaser of U 3 O 8 ,” and in the second, it was “assumed that the uranium productio n industry is able to recove r the entire in crease in the tailings disposal cost by charging higher U 3 O 8 prices.” These two cases provided the lower and upper bound, respectively, of the likely economic impacts of Subpart W on the uranium production industry.

As described in Section 3.1, from 1982 to 1986, the uranium production industry had been contracting and experiencing subs tantial losses because of ex cess production capacity. The 1989 Subpart W economic impact assessment concluded th at if the industry had to absorb the costs of implementing the regulation, the pr esent value cost at that time would be about five times the industry losses from 1982 to 1986, or equal to ab out 10% of the book value of industry assets at that time, or about 15% of industry’s liabilities.

Alternatively, if the uranium production industr y could pass on the Subpart W implementation costs to its electric power industry customer s, who would likely pass on the costs to the electricity users, the 1989 economic impact assessment concluded:

The revenue earned by the [electric power] industry for gene rating 2.4 trillion kilowatt hours of electricity in 1986 was 121.40 billion dollars. The 1987 present value of the regulation (estimated to be $250 million) is less than 1 percent (.06%) of the U.S. total electric power revenue for the same year. [EPA 1989, Section 4.5.1]

The 1989 BID drew no conclusions regarding what effects, if any, these impacts would have on the uranium production indus try’s financial health.

6.2 U 3 O 8 Recovery Baseline Economics

This section presents the baseline economics for development of new conventional mills, ISL facilities, and heap leach fac ilities. EPA’s economic assessment guidelines define the baseline economics as “a reference point th at reflects the world without th e proposed [or in the case of Subpart W, the modified] regulati on. It is the starting point for conducting an economic analysis of potential benefits and costs of a proposed [or modified] regulation” (EPA 2010, Section 5).

The baseline costs were estimated using recently published cost data for actual uranium recovery facilities. For the conventional mill, data from the proposed new mill at the Piñon Ridge project in Colorado were used. For the ISL facility, data from two proposed new f acilities were used: the

first was the Centennial Uran ium project in Colorado and the second was the Dewey-Burdock project in South Dakota. The Cent ennial project is expected to have a 14- to 15-year production75 period, which is a long duration for an ISL facilit y, while the Dewey-Burdoc k project is expected to have a shorter production period of about 9 y ears, which is more representative of ISL facilities. For the heap leach facility, data fr om the Sheep Mountain project in Wyoming were used. Sections 6.2.1 through 6.2.4 provide details of how the project-specif ic cost data were converted into base case economic data, and Se ction 6.2.5 presents a short sensitivity study for the conventional mill and heap leach cost estim ates. Because two projects were analyzed, a sensitivity analysis of the ISL cost estimates was not performed.

Next it was necessary to estimate the annual amount of U 3 O 8 that is currently used and how much would be required in the future. For these estimates, data from the Energy Information Administration (EIA) were used. Section 6.2.6 desc ribes how the EIA data were coupled with specific cost data for the uranium recovery facili ties to determine the cost and revenue estimates provided in Table 18.

Table 18: Uranium Recovery Ba seline Economics (Nondiscounted)

Cost / Revenue 2009 ($1,000) 2035 Projections ($1,000)*

2009$ 2011$ Reference

Nuclear Low Nuclear

Production High Nuclear

Production Ref Low Import

U 3 O 8 Revenue $347,000 $462,000 $502,000 $473,000 $605,000 $706,000

U 3 O 8 Cost $298,000 $372,000

Conventional $398,000 $375,000 $480,000 $560,000

In-Situ Leach $396,000 $373,000 $477,000 $557,000
Heap Leach $356,000 $335,000 $429,000 $501,000

Mixed Facilities $392,000 $368,000 $472,000 $553,000

* See the discussion below and in Sectio n 6.2.6 for a description of these cases.

Table 18 presents uranium productio n industry cost and revenue for six cases. The first two cases

are based on the actual amount of U 3 O 8 produced in the United States in 2009 (the last year for which data are available). The two 2009 cases di ffer in that the first is based on 2009 dollars, including the weighted-average price of $48.92 per pound for uranium of U.S. origin, while the second was based on assumptions used in th is analysis (i.e., 2011 dollars and a U 3 O 8 price of $65 per pound). The remaining four cases in Table 26 are all based on the assumptions used in this analysis, but differ in the amount of U 3 O 8 assumed to be produced in the United States in 2035. The first through third 2035 cases are for the Reference, Low Nuclear Production, and High Nuclear Production projected 2035 nuclear power usage, as estimated by the EIA (see Section 6.2.6). It should be noted that most of the U 3 O 8 used in the United States is from foreign suppliers. The fourth 2035 case (Ref Low Import) increases the percentage of U.S.-origin uranium to 20% for the reference nuclear power usage estimate.

For each of the four 2035 projection cases, four as sumptions were made regarding the source of

the U 3 O 8 : (1) all U 3 O 8 is from conventional mills, (2) all U 3 O 8 is from ISL (recovery) facilities, (3) all U 3 O 8 is from heap leach facilities, and (4) the U 3 O 8 is from a mixture of uranium recovery facilities (see Section 6.2.6, page 87, for a defini tion of the mixture). Table 19 shows that the type of uranium recovery f acility assumed makes only about a 15% difference between the lowest cost (heap leach) and the largest cost (ISL) recovery type facility.76 6.2.1 Conventional Mill Cost Estimate

The base case economic costs for development of a new conventional mill were developed using data from the proposed new mill at Piñon Ridge in Colorado (Edge 2009). Although cost

estimates for other conventional mills were re viewed, e.g., Coles Hill (Lyntek 2010), Church Rock (BDC 2011), the Piñon Ridge cost estimate was selected for the base case because it is believed to be the furthest advanced. Specific co st data obtained from the Piñon Ridge project (i.e., Edge 2009, Tables 7.1-1 and 7.1-2) were for land acquisition and facility construction, operating and maintenance, decommissioning, an d regulatory oversight. While the Piñon Ridge project supplied the mill design parameters and th e overall magnitude of the cost, additional data on the breakdown of the capital and operating co sts were taken from the Coles Hill uranium project located in Virginia (Lyntek 2010).

Assumptions used to develop the conventiona l mill base case cost estimate include:

 As per the Piñon Ridge project, the mill desi gn processing capacity is1,000 tons per day (tpd), and the licensed operati ng processing rate is 500 tpd.

 The operating duration is 40 years, as per the Piñon Ridge project.

 Because they were more detailed, the Coles Hill cost data (Lyntek 2010) were used to generate a percentage brea kdown of the Piñon Ridge cost estimates (Edge 2009). For example, the Piñon Ridge operating cost es timate was divided into labor, power and water, spare parts, office and lab supplies, yellowcake transportati on, tailings operating, and general and administration (G&A) using Co les Hill percentages. Thus, the Coles Hill

data affected the detailed breakdown of th e cost estimate, but not its magnitude.

 Ore grades are 0.142% and 0.086% for underground and open-pit mined uranium, based on data from the EIA (EIA 2010, Table 2). The base case analysis di d not use the Piñon Ridge project’s averag e ore grade of 0.23%.

 The U 3 O 8 recovery rate is 96% pe r the Piñon Ridge project.

 A line of credit (LoC) of $146 million has an annu al interest rate of 4%, with a 20-year payback period.

 The price for U 3 O 8 is $65 per pound (SRK Consulting 2010a, SRK Consulting 2010b, Berger 2009).

 Taxes, claims, and royalties total 11.5% of revenue.

 The discount rates are 3% and 7%, consistent with EPA’s economic analysis guidelines (EPA 2010).77 The Piñon Ridge project data do not include the costs to devel op and/or operate a uranium mine. Rather, it is assumed that these costs are include d in the cost of the uranium ore purchased for processing at the Piñon Ridge mill. Mine development and operating costs are included for the conventional mill based on an average of the ope n pit and underground mine costs developed for the heap leach facili ty (see Section 6.2.2).

Table 19 presents the cost estimates that were developed for the conventional uranium mill.

Table 19: Conventional Mill Cost Estimate

Component Discount Rate

None 3% 7%

Resource mined (1,000 tons) 7,000 N.C. N.C.

U 3 O 8 Recovered (1,000 lb) 15,958 N.C. N.C. Revenues/Costs ($1,000)

Gross Revenue on U 3 O 8 $1,037,299 $617,406 $369,925

Line of Credit (LoC) $146,000 $154,891 $167,155

Mine Costs

Development $82,553 $49,136 $29,440

Operating $261,195 $155,465 $93,148

Mill Costs

Construction $134,073 $139,870 $147,761

Mill Direct $53,136 $55,434 $58,562

Mill Indirect $9,547 $9,960 $10,522

Mill Contingency $15,671 $16,348 $17,271

Tailings $55,718 $58,128 $61,407

Operating and Maintenance $124,397 $74,042 $44,363

Labor (All inclusive) $59,267 $35,276 $21,136

Power & Water $19,400 $11,547 $6,919

Spare Parts $15,883 $9,454 $5,664

Office and Lab Supplies $5,117 $3,045 $1,825

Yellowcake Transportation $2,239 $1,332 $798

Tailings Operating $22,492 $13,387 $8,021

G&A $8,634 $5,139 $3,079

Taxes, Claims, and Royalties $119,289 $71,002 $42,541

Regulatory Oversight $11,800 $7,191 $4,541

Decommissioning/Closure $12,000 $3,679 $801

Repay LoC, plus Finance Costs $214,859 $169,561 $130,302

Total Cost $968,801 $675,085 $495,97878 The cash balance for the conventional mill (as well as the other uranium re covery facilities) is shown in Figure 18. Figure 18 shows that until production year 18, when the LoC has been paid off, the conventional mill is just breaking even.

Figure 18: Estimated Cash Balance – Reference Cases

Figure 19 shows the assumed annual U 3 O 8 production from the conventional mill (as well as the other uranium recovery facilities). Based on the assumptions used for the base case, the conventional mill produces the least amount of U 3 O 8 annually.79 Figure 19: Cumulative U 3 O 8 Projections – Reference Cases

6.2.2 Heap Leach Facility Cost Estimate

The base case economic costs for development of a new heap leach facility were developed using data from the proposed new facility at Sheep Mountain in Wyom ing (BRS 2011). Specific assumptions used to develop the base case cost estimate for the heap leach facility include:

 The operating duration is 13 years, as per the Sheep Mountain project’s uranium production schedule. The annual amount of or e processed averaged 491,758 tons, with maximum and minimum annual processing rates of 916,500 and 74,802 tons, respectively (BRS 2011, page 86).

 The U 3 O 8 production rates were not adjusted to achieve equivalent production rates with the other types of facilities because to do so might affect the facili ty capital costs in a

manner that would be inconsistent with th e estimates provided for the Sheep Mountain project. If additional uranium ore production is to be modeled, a second (or more) and identical heap leach facility should be assume d, either concurrently or sequentially with the first facility.

 Consistent with the Sheep Mountain project co st assumptions, capital investment, totaling $14.177 million, was assumed during the operationa l period to add more heap leach pads and to replace underground mine equipment. Two additional heap pads were assumed, the first after approximately one-third of the ore is processed, and the second after two-thirds is processed.

 Ore grades were 0.142% and 0.086% for unde rground and open-pit mined uranium, based on data from the EIA (EIA 2010, Tabl e 2). The Sheep Mountain project’s ore80 grades averaged 0.132% for underground a nd 0.085% for open-pit produced uranium (BRS 2011, page 86).

 The U 3 O 8 recovery rate varied between 89% and 92%, depending on the year of operation, as per the Sheep Mount ain project (BRS 2011, page 86).

 The cost of open pit mining is $19.28 per t on of ore, while the cost of underground mining is $52.24 per ton, and the cost of h eap leach processing is $13.51 per ton (BRS 2011, pages 87 and 88).

 The price for U 3 O 8 is $65 per pound (SRK Consulting 2010a, SRK Consulting 2010b, Berger 2009).

 An LoC of $125 million has an annual interest rate of 4%, with a 15-year payback period.

 Taxes, claims, and royalties total 11.5% of revenue.

 The discount rates are 3% and 7%, consistent with EPA’s economic analysis guidelines (EPA 2010).

Table 20 presents the cost estimates de veloped for the heap leach facility.

Table 20: Heap Leach Facility Cost Estimate

Component Discount Rate

None 3% 7%

Resource mined (1,000 tons)

Open Pit 2,895 N.C. N.C.
Underground 3,498 N.C. N.C.

U 3 O 8 Recovered (1,000 lb) 13,558 N.C. N.C. Revenues/Costs ($1,000)

Gross Revenue on U 3 O 8 $881,266 $764,878 $643,637

Line of Credit (LoC) $125,000 $136,591 $153,130

Open Pit Mine

Capital Costs $14,590 $14,590 $14,590

Operating Costs $55,817 $49,594 $42,879

Underground Mine

Capital Costs $60,803 $59,880 $58,997

Operating Costs $182,723 $156,753 $130,078

Heap Pads/Processing Plant

Capital Costs $51,885 $50,788 $49,690

Operating Costs $86,367 $74,973 $63,13081 Table 20: Heap Leach Facility Cost Estimate

Component Discount Rate

None 3% 7%

Shared Costs

Predevelopment $10,630 $11,149 $11,874

Reclamation Costs $17,000 $14,755 $12,416

Taxes, claims, and royalties $101,346 $87,961 $74,018

Repay LoC/Finance Costs $168,640 $146,659 $125,441

Total Cost $749,801 $667,102 $583,114

Figure 18 end of year cash balance for the heap leach facility (as well as for the other uranium recovery facilities). Figure 18 shows that by production year 4, the heap leach facility has a positive cash balance. Figure 19 shows the assumed annual U 3 O 8 production from the heap leach facility (as well as from the othe r uranium recovery facilities). Based on the assumptions used for the base case, the heap leach facility consistently produ ces the largest quantity of U 3 O 8 annually.

6.2.3 In-Situ Leach (Long) Facility Cost Estimate

The base case economic costs for development of a new ISL facility were estimated using data from the proposed new Centennial project in Weld County, Colorado (SRK Consulting 2010b). The Centennial project is expected to have a production period of 14–15 years, which is a long duration for an ISL facility. Annual cost estima tes for the Centennial project are provided on pages 117 through 123 of SRK Consulting 2010b. SRK Consulting 2010b, Section 17.11,

discusses the basis for the Cente nnial project cost estimate. Speci fic assumptions used to develop the ISL (Long) facility base case cost estimate for this analysis include:

 The operating duration is 15 years, as per the Centennial projec t’s uranium production schedule (SRK Consulting 2010b, pages 117 an d 120). The facility produces about 700,000 lb of U 3 O 8 annually in the first 12 years, then reduces production until only 92,000 lb is produced in the last (15 th ) year.

 The U 3 O 8 production rates were not adjusted to achieve equivalent production rates with the other types of facilities because to do so mi ght affect the ISL facili ty capital costs in a

manner that would be inconsistent with the es timates provided for the Centennial project.

If additional U 3 O 8 production is to be modeled, a s econd (or more) and identical ISL (Long) facility should be assumed, either conc urrently or sequentially with the first facility.

 Ground water restoration of a mining unit is assu med to begin as soon as practicable after mining in the unit is complete (SRK Consulting 2010b, pages 17–24). Funds for

restoration are set aside be ginning in the second production year and continuing until the end of the project (i.e., year 19 after the start of production).

 The price for U 3 O 8 is $65 per pound (SRK Consulting 2010a, SRK Consulting 2010b, Berger 2009).82  An LoC of $85 million has an annual interest rate of 4%, with a 10-year payback period.

 Taxes, claims, and royalties total 11.5% of revenue.

 The discount rates are 3% and 7%, consistent with EPA’s economic analysis guidelines (EPA 2010).

Table 21 presents the cost estimates that were developed for the ISL (Long) facility.

Table 21: In-Situ Leach (Lon g) Facility Cost Estimate

Component Discount Rate

None 3% 7%

U 3 O 8 Recovered (1,000 lb) 9,522 N.C. N.C. Revenues/Costs ($1,000)

Gross Revenue on U 3 O 8 $618,930 $501,943 $390,820

Line of Credit (LoC) $85,000 $87,550 $90,950

Operating Cost Summary

Central Plant/Ponds $66,536 $52,000 $38,805

Satellite/Well Field $126,708 $109,218 $90,279

Restoration $11,257 $8,353 $5,844

Decommissioning $14,818 $9,175 $5,017

G&A Labor $16,379 $12,849 $9,732

Corporate Overhead $6,350 $4,969 $3,761

Contingency $48,410 $39,313 $30,687

Total Operating Costs $290,458 $235,877 $184,124

Capital Cost Summary

CPP/General Facilities $55,097 $54,027 $52,739

Well Fields $14,209 $13,868 $13,450

G&A $13,605 $13,428 $13,212

Mine Closure $12,585 $7,244 $3,555

Miscellaneous $14,246 $11,055 $8,202

Contingency $21,948 $19,924 $18,232

Total Capital Costs $131,690 $119,546 $109,390

Severance, Royalty, Tax $71,177 $57,723 $44,944

Repay LoC/Finance Costs $104,797 $92,076 $78,758

Total Cost $598,122 $505,223 $417,216

Figure 18 shows the end of year cas h balance for the ISL (Long) faci lity (as well as for the other uranium recovery facilities). Figure 18 show s that by the second year of production, the ISL (Long) facility has a positive cash balance. Figure 19 shows the assumed annual U 3 O 8 production from the ISL (Long) facility (as well as from the other uraniu m recovery facilities). Based on the assumptions used for the base ca se, the ISL (Long) facil ity produces an annual83 amount of U 3 O 8 that is midway between the amounts produced by the conventional mill and heap leach facility.

6.2.4 In-Situ Leach (Short) Facility Cost Estimate

The base case economic costs for development of a new ISL facility were estimated using data from the proposed new Dewey-Burdock project in South Dakota (SRK Consulting 2010a). The Dewey-Burdock project is expect ed to have a production period of about 9 years, which is representative for an ISL facility. SRK Cons ulting 2010a, pages 96 through 105, presents annual cost estimates for the Dewey-Burdock project, and Section 17.11 of that report discusses the basis for the Dewey-Burdock project cost estimate. Specific assumptions used to develop the ISL (Short) facility base case cost estimate for this analysis include:

 The operating duration is 9 years, as per the Dewey-Burdock project’s uranium production schedule (SRK Consulting 2010a, pa ges 117 and 120). The facility produces about 1,010,000 lb of U 3 O 8 annually in the first 6 years, then production declines until only 533,000 lb is produced in the last (9 th ) year.

 The U 3 O 8 production rates were not adjusted to achieve equivalent production rates with the other types of facilities because to do so mi ght affect the ISL facili ty capital costs in a

manner that would be inconsistent with th e estimates provided for the Dewey-Burdock project. If additional U 3 O 8 production is to be modeled, a second (or more) and identical ISL (Short) facility should be assumed, either concurrently or sequentially with the first facility.

 Ground water restoration of a mining unit is assu med to begin as soon as practicable after mining in the unit is complete (SRK Consulting 2010a, pages 17–18). Funds for restoration are set aside begi nning in the first production ye ar and continuing for 2 years after production ends (i.e ., production year 11).

 The price for U 3 O 8 is $65 per pound (SRK Consulting 2010a, SRK Consulting 2010b, Berger 2009).

 An LoC of $70 million has an annual interest rate of 4%, with a 5-year payback period.

 Taxes, claims, and royalties total 11.5% of revenue.

 The discount rates are 3% and 7%, consistent with EPA’s economic analysis guidelines (EPA 2010).

Table 22 presents the cost estimates de veloped for the ISL (Short) facility.84 Table 22: In-Situ Leach (Sho rt) Facility Cost Estimate

Component Discount Rate

None 3% 7%

U 3 O 8 Recovered (1,000 lb) 8,408 N.C. N.C. Revenues/Costs ($1,000)

Gross Revenue on U 3 O 8 $546,520 $491,065 $431,098

Line of Credit (LoC) $70,000 $72,100 $74,900

Operating Cost Summary

Central Plant/Ponds $31,036 $27,485 $23,754

Satellite/Well Field $130,056 $116,074 $100,788

Restoration $6,159 $5,207 $4,234

Decommissioning $11,614 $8,594 $5,835

G&A Labor $9,750 $8,637 $7,500

Corporate Overhead $3,900 $3,450 $2,994

Contingency $38,503 $33,889 $29,021

Total Operating Costs $208,558 $186,696 $162,811

Capital Cost Summary

CPP/General Facilities $49,338 $50,297 $51,598

Well Fields $37,127 $36,951 $36,787

G&A $2,507 $2,463 $2,414

Mine Closure $22,460 $16,640 $11,314

Miscellaneous $9,565 $8,253 $6,927

Contingency $19,707 $19,593 $19,545

Total Capital Costs $140,705 $134,197 $128,586

Severance, Royalty, Tax $83,444 $74,899 $65,698

Repay LoC/Finance Costs $78,619 $74,171 $68,984

Total Cost $511,326 $469,963 $426,079

Figure 18 shows the end of year cas h balance for the ISL (Short) fac ility (as well as for the other uranium recovery facilities). Figure 18 shows that in its first year of production, the ISL (Short) facility has a positive cash balance. Figure 19 shows the assumed annual U 3 O 8 production from the ISL (Short) facility (as well as from the ot her uranium recovery facilities). Based on the assumptions used for the base case, the ISL (S hort) facility produces an annual amount of U 3 O 8 that is midway between the amounts produced by the ISL (Long) and heap leach facilities.

6.2.5 Cost Estimate Sensitivities

The uranium recovery facility base case cost estimates developed in Sections 6.2.1 through 6.2.4 were based on the specific assumptions presented in each section. One of the key parameters for the determination of the conventional mill and heap leach facility cost estimates is the assumed ore grade. Table 23 presents the average ore gr ades reported by the EIA for U.S.-origin uranium during 2009. These are the ore grades assumed for the conventional mill and heap leach facility

cost estimates. As noted in S ection 6.2.2, the ore grad es assumed in the Sheep Mountain project85 cost estimate (BRS 2011) were very similar to th e Table 23 values. However, as noted in Section 6.2.1, the Piñon Ridge project cost estimate used an ore grade of 0.23%, which is considerably higher than the Table 23 EIA values (Edge 2009).

Table 23: Uranium Ore Grade

Mine Type Ore Output (1,000 tons) Ore Grade

Underground 76,000 0.142%

Open Pit 54,000 0.086%

In-Situ Leach 145,000 0.08%

Total 275,000 0.10%

Source: EIA 2011b

Table 24 summarizes the cost estimates for all f our uranium recovery f acilities developed in Sections 6.2.1 through 6.2.4. It includes the heap leach facility and conve ntional mill sensitivity cost estimates based on the alternate ore grade a nd ore processing assumpti ons just described.

Table 24: U 3 O 8 Market Value and Cost to Produce (Nondiscounted)

Average U 3 O 8 Price ($/lb) $65.00

Average U 3 O 8 Cost ($/lb) w/ LoC 1 w/o LoC 2

Conventional $51.56 $47.24
ISL (Long) $53.89 $51.81
ISL (Short) $52.49 $51.46
Heap Leach $46.08 $42.87
Conventional as Designed $26.57 $25.45
Heap Leach w/ High Grade Ore $22.13 $20.59

1 Total cost minus LoC revenue divided by the pounds of U 3 O 8 produced

2 Total cost minus LoC revenue minus finance charge divided by the pounds of U 3 O 8 produced.

The Piñon Ridge mill is being designed to pr ocess 1,000 tpd of uranium ore but, because of current market conditions, is currently being lice nsed to process only 500 tpd. The cost estimate

in Section 6.2.1 is based on a conventional mill processing 500 tpd. As an alternative, the

conventional mill cost estimate is recalculated us ing an ore grade of 0.23% and an ore processing rate of 1,000 tpd. These results ha ve been included in Table 24.

So that the facilities maintain a positive cash flow, the analyses in Sections 6.2.1 through 6.2.4 assumed that each facility would be provided with an LoC to cover the construction and development costs. The amount of the LoC was determined by how much cash was necessary to maintain a positive cash balance. The interest on the LoC was assumed to be 4%, and the period to repay the LoC varied for each facility, depend ing on the amount of the LoC. The interest paid

on the LoC is included in the facility cost estimates develo ped in Sections 6.2.1 through 6.2.4.86 The right hand column of Table 24 shows what th e facility-specific cost estimates would be without an LoC (and if the cash flow was allowed to be negative), or if th e interest rate was 0%.

Figure 20 shows the effect of alternat ive assumptions on the cash balance.

Figure 20: Estimated Cash Balance – Sensitivity Cases

Figure 21 shows the effect of the alternative assumptions on the U 3 O 8 production. The obvious conclusion is that the higher the ore grade, the more U 3 O 8 is produced, and therefore, the uranium recovery facility is more profitable.87 Figure 21: Cumulative U 3 O 8 Projections – Sensitivity Cases

6.2.6 Annual Total U 3 O 8 Cost Estimates

In Sections 6.2.1 through 6.2.4, base case cost estim ates were developed for a conventional mill, a heap leach facility, and two IS L facilities. These individual ur anium recovery facility cost estimates are used together with the actual 2009 (the last year for which data are available) and projected 2035 U.S.-origin uranium production.

For 2009, the EIA reports that 7,100 thousand pounds of U 3 O 8 was produced in the United States (EIA 2011b). For this analysis, the total produced was divided between conventional mills and ISL facilities using the EIA-pr ovided ore outputs, shown in Table 23, which resulted in 3,356,000 lb for conventional mills and 3,744,000 lb for ISL facilities. No heap leach facilities were operating in 2009, so the h eap leach production is zero. The 2009 uranium recovery facility

total cost and revenue estimat es given in Table 18 (page 75) are based on these U 3 O 8 production figures and the individual facility uni t cost estimates given in Table 24.

These calculated 2009 economic data are ba sed on 2011 dollars (e.g., $65 per pound of U 3 O 8 ). The 2009 calculated economic data are adjust ed to 2009 dollars by assuming an average U 3 O 8 price of $48.92 lb -1 (EIA 2010) and adjusting the costs by the ratio of the 2009 energy consumer price index (CPI, 202.301) to the 2011 ener gy CPI (252.661) (BLS 2011, Table 25). Table 18 (page 75) also gives the 2009 economic data estimates based on 2009 dollars for uranium recovery facilities.

The next part of the analysis was to estimate the future value of the U.S. uranium recovery industry. To this end, it was necessary to estimate the future size of the nuclear power industry. The EIA (2011a) analyzed the U.S. ener gy outlook for 2011 and beyond, including the contribution from nuclear power. The EIA analyzed a reference case, plus 46 alternative cases,88 and determined the nuclear power contribution for each. The EIA reported that in 2010, nuclear power produced 803×10 9 kilowatt-hours of electricity and projected that for the reference case, nuclear power would produce 874×10 9 kilowatt-hours in 2035 (EIA 2011a). Of the 46 alternative cases, the Greenhouse Gas (GHG) Price Economyw ide and Integrated High Technology cases had the largest and smallest projected nuclear power contributions in 2035, respectively. The GHG Price Economywide case was pr ojected to contribute 1,052×10 9 kilowatt-hours in 2035, while the Integrated High Technology cas e was projected to contribute 823×10 9 kilowatt-hours. Figure 22 shows and compares the EIA projections.

Source: EIA 2011a Figure 22: Nuclear-Generate d Electricity Projections

It is assumed that the 2035 to 2009 U 3 O 8 requirements would have the same ratio as the 2035 to 2010 EIA (2011a) nuclear power estimates. Thus, for the EIA Reference Nuclear, Low Nuclear Production (Integrated High Technology), and High Nuclear Pr oduction (GHG Price Economywide) cases, the total U 3 O 8 requirements in 2035 are estimated to be 7,728, 7,277, and 9,302 thousand pounds, respectively. Costs were es timated for four cases, with each case assuming a different type of uranium recovery facility responsible fo r producing the required

U 3 O 8 . The cases are (1) only conventional mills, (2 ) only ISL facilities, (3) only heap leach facilities, and (4) a mixture of all three types of facilities.

To divide the total U 3 O 8 requirement among the three types of uranium recovery facilities for Case 4, it is assumed that one reference heap l each facility would be ope rational, and that the

remainder of the U 3 O 8 would be divided between conventiona l mills and ISL facilities with the same ratio as in 2009. The total amount of U.S.-origin U 3 O 8 for each of the 2035 projections is shown in Table 25 for Case 4. For the remaining three cases, the total 203 5 projections given in Table 25 were assumed to be produced by the part icular mine type asso ciated with the case.89 Table 25: Assumed Case 4 U 3 O 8 Production Breakdown by Mine Type

Mine Type U 3 O 8 Produced (1,000 lb)

2009 2035 Projections

Reference

Nuclear Low Nuclear

Production High Nuclear

Production Ref Low Import

Conventional 3,356 3,159 2,947 3,903 4,642

In-Situ Leach 3,744 3,525 3,287 4,355 5,178
Heap Leach

― 1,043 1,043 1,043 1,043

Total 7,100 7,728 7,277 9,302 10,862

Source: EIA 2011b

The 2035 total cost and revenue estimates for uran ium recovery facilities appear in Table 18 (page 75) and are based on the Table 25 U 3 O 8 productions and the individual facility unit cost estimates given in Table 24. Refer to Section 6.2 for a discussion of the Table 18 total cost and revenue estimates. Table 26 gives a breakdown by facility type for Case 4, the mixed uranium recovery facility case.

Table 26: Case 4 (Mixed Uranium Rec overy Facilities) Economic Projections (Nondiscounted)

Cost/Revenue 2035 Projections ($1,000)

Reference

Nuclear Low Nuclear

Production High Nuclear

Production Ref Low Import

U 3 O 8 Revenue $502,305 $472,994 $604,605 $706,057

Conventional $205,407 $191,551 $253,767 $301,726

In-Situ Leach $229,108 $213,653 $283,048 $336,541
Heap Leach $67,790 $67,790 $67,790 $67,790

U 3 O 8 Cost $391,584 $368,411 $472,461 $552,668

Conventional $162,932 $151,941 $201,292 $239,334

In-Situ Leach $180,590 $168,409 $223,108 $265,273
Heap Leach $48,062 $48,062 $48,062 $48,062

The EIA (2010, Table S1a) shows that most of the U 3 O 8 purchased in the United States is of foreign origin (see Figure 23). In 2009, the 7,100 thousand pounds of U 3 O 8 produced in the United States amounted to only 14.2% of the total amount of U 3 O 8 purchased. Since the total cost and revenue estimates in Table 18 (pag e 75) are based on the 2009 U.S.-produced U 3 O 8 , then those estimates include the assump tion that 85.8% of the U.S.-purchased U 3 O 8 is of foreign origin. As Figure 23 shows, the amount of foreign origin U 3 O 8 has fluctuated over time. If all of

the U 3 O 8 that is purchased in the United States were to be supplied domestically, then the total

cost and revenue estimates shown in Table 18 w ould increase by a factor of 7 (i.e., 1/0.142 = 7). However, this is considered to be unrealistic and is unsupported by the data shown in Figure 23. As an alternative, the Ref Low Import case s hown in Table 18 assumes that 20% of the 2035

EIA Reference case U 3 O 8 needs would be met domestically.90 Source: EIA 2010, Table S1a Figure 23: U.S. and Fo reign Contribution to U 3 O 8 Purchases

6.3 Economic Assessment of Proposed GACT Standards

EPA is proposing to revise Subpart W by introd ucing three categories re lated to how uranium recovery facilities manage byproduct materials du ring and after the processing of uranium ore. are presented and described in Section 5.4 presen ts and describes the proposed GACTs for each category. This section presents the costs and bene fits associated with the implementation of the various components of the GACTs. The first ca tegory is the standards for conventional mill tailings impoundments. The s econd category consists of re quirements for nonconventional impoundments where uranium byproduct material (i.e., tailings) is contained in ponds and covered by liquids. Examples of this category ar e evaporation or holding ponds that exist at conventional mills and ISR and heap leach facil ities. Requirements in this second category are that the nonconventional impoundme nts be provided with a double liner (Section 6.3.2) and that liquid at a depth of 1 meter be maintained in the impoundment (S ection 6.3.3). The third category of revised Subpart W would require that heap leach piles be provided with a double liner (Section 6.3.4) and that the pile’s moisture content be ma intained above 30% by weight (Section 6.3.5). Additionally, the revised Subpart W would remove the requirement to monitor

the radon flux at conventional facilities cons tructed on or prior to December 15, 1989 (Section 6.3.1).

6.3.1 Method 115, Radon Flux Monitoring

Existing Subpart W regulations require licen sees to perform annual monitoring using

Method 115 to demonstrate that the radon flux at conventional impoundment s constructed before December 15, 1989, is below 20 pCi/(m 2 -sec). The elimination of this monitoring requirement91 would result in cost savings for the three facilit ies to which this requirement still applies: Sweetwater, White Mesa , and Shootaring Canyon. 9

Radon Flux Monitoring Unit Costs

Method 115 requires that multiple large-area ac tivated charcoal collectors (LAACCs) be employed to make radon flux measurements. The first step in preparing this cost estimate was to develop the cost for making a single LAACC radon flux measur ement. Unit cost data for performing LAACC radon flux measurements were obtained from three primary sources: the “Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM)” (EPA 2000a), KBC Engineers (KBC 2009), and Waste Control Specialists (WCS 2007). Weston Solutions provided fully loaded billing rates for radiati on safety officers (RSOs) and certified health physicists (CHPs) (WS 2003).

MARSSIM (EPA 2000a)

― MARSSIM is a multivolume document that presents methodologies for performing radiation surveys. Appendix H to MARSSIM describes field survey and laboratory analysis equipment, including the estimated cost per measurement. Included in Appendix H is the cost estimate for perfor ming an LAACC measurement. The MARSSIM estimated cost range for LAACC radon flux measurements is $20 to $50 per measurement, including the cost of the can ister. Since MARSSIM, Revisi on 1, was published in August 2000,

it is assumed that this cost estimate is in 2000 dollars. MARSSIM does not estimate the cost for deploying the canisters or fo r final report preparation.

KBC Engineers (KBC 2009)

― In November 2009, KBC Engineers prepared a revised “Surety Rebaselining Report” for the Kennecott Uraniu m Company’s Sweetwater Uranium Project,

which included an estimate for the cost of performing Method 115 radon flux monitoring. KBC based the canister testing cost of $50 per canister on past in voices received from Energy Laboratories, Inc. (a commercial analytical labora tory). In addition to the cost for the laboratory work, KBC included estimates for setting up and retrieving canisters in the field and for data analysis and report preparation. KBC estimated th at a technician/engineer with a fully loaded billing rate of $100 per hour would require 40 hou rs to set up and retrie ve 110 canisters, or $36.36 per canister. Also, KBC estimat ed that an engineer/scientist with a fully loaded billing rate of $105 per hour would require 20 hours for data analysis and report preparation for the 110 canisters, or $19.06 per canis ter. The KBC unit cost es timates are in 2009 dollars.

Waste Control Specialists (WCS 2007)

― In its application to cons truct and operate a byproduct material disposal facility, 10 Waste Control Specialists, LLC (WCS) included a closure plan and corresponding cost estimate. As part of the final status survey, th e radon flux through the disposal unit cap will be measured using LAAC Cs. WCS used the MARSSIM value as the cost for testing the canister. In a ddition, WCS included the cost of an RSO at $75 per hour to conduct the survey and prepare report and the cost of a CHP at $104 per hour to review the survey data. For the 100 canisters assumed, WCS assumed the RSO would require 40 hours for a cost of $30

9 Cotter Corporation has indicated that the primary impoundments at its Cañon City site are no longer active, and thus, it has stopped performing Subpart W radon flux monitoring at that site (Thompson 2010).

10 The WCS facility is not a conventional tailings facility or a uranium recovery facility. It was specially

constructed to handle the K-65 residues that were stored at DOE’s Fernald site.92 per canister and the CHP would require 10 hours, or $10.40 per canis ter. The WCS unit costs are

in 2004 dollars.

Weston Solutions (WS 2003)

― Weston Solutions did not estimate the cost associated with Method 115 radon flux monitoring, but it did include the fully loaded hourly billing rates for radiation supervisors (equivalent to RSOs) and CHPs of $78 and $133, respectively. These billing rates are in 2003 dollars.

Unit Costs

― Table 27 summarizes the data provided in the four source documents. The first step was to adjust all of the data to constant 2011 dol lars. The CPI (DOL 2012) was used to make this adjustment. The right side of Tabl e 27 shows the adjusted cost data.

Table 27: Data Used to Develop Method 115 Unit Costs

Data as Provided Adjusted to November 2011 (CPI = 226.23)

Source Date CPI Cost per Canister Cost per Canister

Testing Setup/

RSO Analysis/

CHP Testing Setup/

RSO Analysis/

CHP

EPA 2000a Aug-00 172.8 $20.00 N.G. N.G. $26.18 N.G. N.G.

$50.00 N.G. N.G. $65.46 N.G. N.G.

WS 2003 Dec-03 184.3 N.G. $31.20 $13.30 N.G. $38.30 $16.33

WCS 2007 May-07 207.949 $25.00 $30.00 $10.40 $27.20 $32.64 $11.31

$50.00 $54.40

KBC 2009 Nov-09 216.33 $50.00 $36.36 $19.09 $52.29 $38.03 $19.96
N.G. = not given in the source document

Based on the data from Table 27, minimum, av erage, and maximum unit costs for performing Method 115 radon flux monitoring were esti mated and are shown in Table 28.

Table 28: Method 115 Unit Costs

Type LAACC Unit Cost ($/Canister) Testing Setup/RSO Analysis/CHP Total

Minimum $26.18 $32.64 $11.31 $70.14

Average $45.11 $36.32 $15.87 $97.29

Maximum $65.46 $38.30 $19.96 $123.72

Total Annual Cost Savings (Benefit)

Method 115 requires 100 measurements per year as the minimum number of flux measurements considered necessary to determin e a representative mean radon fl ux value. Additionally, if there are exposed beaches or soil-covered areas (as is likely at White Mesa), then an additional 100 measurements are necessary. Thus, for the th ree sites still require d to perform Method 115 radon flux monitoring, the average annual cost to pe rform that monitoring (based on the Table 28 LAACC unit costs) is estimated to be about $9,730 per site per year for Shootaring and93 Sweetwater, and $19,460 for White Mesa. For all thr ee sites the total annual average cost is estimated to be $38,920 yr -1 , with a range from approximately $28,000 to $49,500 yr -1

.

6.3.2 Double Liners for Nonconventional Impoundments

Uranium byproduct materials are often stored in onsite impoundments at uranium recovery facilities, including in holdi ng ponds and evaporation ponds. Th ese ponds can be collectively referred to as nonconventional impou ndments, to distinguish them from conventional tailings impoundments. This section provides an estimate of the cost to provi de these nonconventional impoundments with a double liner, including a leak collection laye r. Figure 24 shows a typical design of an impoundment double liner.

Source: Golder 2008, Drawing 8

Figure 24: Typical Double-Lined Impo undment with Leak Collection Layer

Double Liner Unit Costs

Unit costs, per square foot of liner, have been estimated for the thre e components of the double liner system: the geomembrane (HDPE) liner, the drainage (Geonet) layer, and the geosynthetic clay liner (GCL).

HDPE Unit Cost

― The geomembrane (HDPE) liner insta llation unit cost es timates shown in

Table 29 were obtained from the indicated documen ts and Internet sites. The Table 29 unit costs include all required labor, materials, and ma nufacturing quality assurance documentation costs (Cardinal 2000, VDEQ 2000). Where necessary, the un it costs were adjusted from the year they were estimated to year 2011 dollars using th e CPI. The Table 29 geomembrane (HDPE) liner
mean unit cost is $0.95 ft -2 , the median cost is $0.74 ft -2 , while the minimum and maximum costs are $0.45 and $2.35, respectively.94 Table 29: Geomembrane (HDPE) Liner Unit Costs

Data Source Unit Cost (ft -2 ) Thickness - Area As Given 2011$
Foldager 2003 $0.37 $0.45 Not Specified

Vector 2006 $0.45 $0.50 60 mil

Cardinal 2000 $0.39 $0.51 60 mil - 470,800 SF

Cardinal 2000 $0.40 $0.52 60 mil - 138,920 SF

Earth Tech 2002 $0.45 $0.57 60 mil

Cardinal 2000 $0.47 $0.61 60 mil - 118,800 SF VDEQ 2000 $0.48 $0.63 60 mil
Duffy 2005 $0.60 $0.70 40 mil

Get-a-Quote $0.70 $0.70 40 mil

Cardinal 2000 $0.54 $0.71 60 mil - 60,600 SF

MWH 2008 $0.70 $0.74 40 mil
Project Navigator 2007 $0.70 $0.76 60 mil

MWH 2008 $0.80 $0.84 80 mil

Get-a-Quote $0.86 $0.86 60 mil

EPA 2004 $0.80 $0.96 60 mil

Get-a-Quote $1.04 $1.04 80 mil

Free Construction $1.05 $1.05 40 mil

Free Construction $1.69 $1.69 60 mil
Foldager 2003 $1.40 $1.72 Not Specified

Free Construction $2.00 $2.00 80 mil
Lyntek 2011 $2.35 $2.35 80 mil

Drainage Layer (Geonet) Unit Cost

― Some of the documents re viewed included unit cost estimates for installation of the drainage (Ge onet) layer, as shown in Table 30. As with the geomembrane (HDPE) liner unit costs, the drainage (Geonet) layer unit costs were adjusted from the year they were estimated to year 2011 dolla rs using the CPI. The Table 30 drainage layer (Geonet) mean unit cost is $0.64 ft -2 , the median cost is $0.57 ft -2 , while the minimum and maximum costs are $0.48 and $1.02, respectively.

Table 30: Drainage Layer (Geonet) Unit

Costs

Data Source Unit Cost (ft -2 )

As Given 2011$

EPA 2004 $0.40 $0.48
Project Navigator 2007 $0.45 $0.49

Earth Tech 2002 $0.45 $0.57

MWH 2008 $0.60 $0.63
Duffy 2005 $0.88 $1.0295 Geosynthetic Clay Liner (GCL) Unit Cost

― Some of the documents reviewed also included unit cost estimates for installation of the GCL, as shown in Table 31. As for the geomembrane (HDPE) liner unit costs, the CPI was used to ad just the GCL unit costs from the year they were estimated to year 2011 dollars. The Ta ble 31 GCL mean unit cost is $0.69 ft -2 ; the median cost is
$0.65 ft -2 ; and the minimum and maximum co sts are $0.45 and $1.12, respectively.

Table 31: Geosynthetic Clay Liner (GCL) Unit Costs

Data Source Unit Cost (ft -2 )

As Given 2011$

Vector 2006 $0.40 $0.45

EPA 2004 $0.40 $0.48

Earth Tech 2002 $0.52 $0.65
Project Navigator 2007 $0.70 $0.76

Lyntex 2011 $1.12 $1.12

Some designs may choose to use a compacted cl ay layer beneath the dou ble liner (e.g., Figure 26). However, Sandia (1998) has found that “[r]ep lacing the 60 cm thick clay (amended soil) barrier layer with a GCL drastically reduced the co st and difficulty of construction.” This savings was due to avoiding the expense of obtaining the bentonite clay and the difficulties of the clay being “sticky to spread and slippery to driv e on,” plus “compaction was extremely difficult to achieve.” For these reasons, it is believed that GCL will be used in most future applications and is thus appropriate for this cost estimate.

Design and Engineering

― The cost estimates include a 20% allowance for design and engineering for the mean and median estimates , and a 10% and 20% allowance for the minimum and maximum estimates, respectively. The design and engineering cost has been calculated by multiplying the capital and installation cost by the allowance factor.

Contractor Oversight

― The cost estimates include a 20% allowance for contractor oversight for the mean and median estimates, and a 15% and 25% allowance for the minimum and maximum estimates, respectively. The contractor oversight cost has been calculated by multiplying the capital and installation cost by the allowance factor.

Overhead and Profit

― The cost estimates include a 20% a llowance for overhead and profit for the mean and median estimates, and a 15% and 25% allowance for the minimum and maximum estimates, respectively. The overhead cost and pr ofit has been calculated by multiplying the sum of the capital and installation, design and engi neering, and contractor oversight costs by the

allowance factor.

Contingency

― The cost estimates include a contingency factor of 20% for the mean and median estimates, and 15% and 25% for the minimu m and maximum estimates, respectively. The contingency has been calculated by multiplyi ng the sum of all of the other costs by the contingency factor.96 Double Liner Capital and Installation Cost

Impoundment Areas

― Figure 25 shows that in order to an chor the upper liner and drainage layer (Geonet), an additional 8.5 ft of materi al is required on each side of the impoundment. Similarly, an additional 6 ft of material is re quired on each side of the impoundment to anchor

the lower liner and the GCL.

Source: Golder 2008, Drawing 8 Figure 25: Typical Double Liner Anchor System

Section 6.2 describes base faciliti es for each type of uranium r ecovery facility: conventional, ISR, and heap leach. Since they are not give n in Section 6.2, Table 32 shows the impoundment

surface areas for each of the base facilities, plus the areas of the upper liner, drainage layer (Geonet), lower liner, and GCL. Th e liner areas include additional ma terial in order to anchor the liner, plus an additional 10% to account for the sloping of the sides and waste.

Table 32: Nonconventional Impoundment Areas

Facility Type Impoundment Type Number Area (acres)

Surface Upper Liner

& Geonet Lower Liner

& GCL

Conventional Evaporation 10 4.13 4.94 4.82
(Golder 2008) Total 10 41.30 49.39 48.22

ISR Water Storage 10 7.20 8.41 8.26
(Powertech 2009) Process Water 1 3.31 3.98 3.88

Total 11 75.31 88.05 86.50

Heap Raffinate 1 0.9 1.17 1.11

(Titan 2011) Collection 1 1.5 1.88 1.81

Evaporation 1 5.7 6.71 6.58

Total 3 8.10 9.75 9.50

Impoundment Double Liner Cost

― Based on the above estimated quantities of material and unit costs, Table 33 presents the median, minimu m, and maximum capital costs for installing the97 double liner beneath the impoundments of each of the three types of uranium recovery facilities: conventional, ISR, and heap leach.

Table 33: Base Facility Nonconventional Impoundment Double Liner Capital and Installation Costs

Cost Type Conventional ISR Heap

Mean $13,800,000 $24,700,000 $2,700,000

Median $11,500,000 $20,600,000 $2,300,000

Minimum $6,500,000 $11,600,000 $1,300,000

Maximum $32,900,000 $58,900,000 $6,500,000
Mean, w/o Upper Liner $6,800,000 $12,100,000 $1,300,000

To demonstrate the individual component contribu tion to the total capita l and installation cost, Table 34 presents the calculated mean capital cost breakdown by category.

Table 34: Mean Base Facility Nonconventional Impoundment Double Liner Capital and Installation Cost Breakdown

Liner Component Unit Cost (ft -2 ) Mean Impoundment Double Liner Capital and Installation Cost

Conventional ISR Heap Upper Liner $0.95 $2,040,654 $3,638,014 $402,799
Drainage (Geonet) $0.64 $1,370,814 $2,443,844 $270,581
Lower Liner $0.95 $1,992,191 $3,573,958 $392,414
GCL $0.69 $1,455,818 $2,611,714 $286,761
Design & Engineering 20% $1,371,895 $2,453,506 $270,511
Contractor Oversight 20% $1,371,895 $2,453,506 $270,511
Overhead & Profit 20% $1,920,654 $3,434,908 $378,715
Contingency 20% $2,304,784 $4,121,890 $454,459

Total

― $13,828,706 $24,731,338 $2,726,751

Table 33 includes capital and annual cost estimates for a mean, without upper liner case. This case was added because, even if not required to comply with 40 CFR 192.32(a)(1), the design of nonconventional impoundments at uranium recovery facilities would incl ude at least a single liner. The reason is that the NRC, in 10 CFR 40, Appendix A, Criterion 5(A), requires that “... surface impoundments (...) must have a liner that is designed, constructed, and installed to prevent any migration of wastes out of the im poundment to the adjacent subsurface soil, ground water, or surface water ... .” Thus, the Mean, w/o Upper Liner case estimates the cost to upgrade a single liner to a double liner sy stem (i.e., the cost of the uppe r liner and the GCL have been removed).

Double Liner Total Annual Cost

Section 6.2.6 (Table 25) provi ded projections of the U 3 O 8 requirements in the year 2035 for four different nuclear usage scenar ios: Reference Nuclear – 7,728,000 lb; Low Nuclear Production – 7,277,000 lb; High Nuclear Production – 9,302,000 lb; and Reference Low Import – 10,862 lb.98 Table 35 presents the calculated annualized cost for instal lation of a double liner in a nonconventional impoundment for the 2035 projected U 3 O 8 productions. The annualized cost was calculated by first dividing the capital cost of the double liner by the total amount of U 3 O 8 expected to be produced during the lifetime of each uranium recovery facility, and then multiplying by the projected amount of U 3 O 8 produced annually. Table 35 presents four cases. In the first three cases, it was assumed that a singl e type of uranium rec overy facility would produce all of the U 3 O 8 required in 2035, while in the fourth case, it was assumed that a mixture of uranium recovery facilities would be operating in 2035. For the fourth case, Table 25 gives the

contribution to the total U 3 O 8 required in 2035 by each type of facility.

Table 35: Projected Nonconventional Impoundment Double Liner Annualized Capital and Installation Costs

Cost Type Projected 2035

U 3 O 8 Production Annualized Capital and Installation Cost ($/yr)

Conventional ISR Heap Mix

Mean Reference Nuclear $6,700,000 $22,700,000 $1,600,000 $14,800,000

Median Reference Nuclear $5,600,000 $18,900,000 $1,400,000 $12,400,000

Minimum Low Nuclear Production $2,900,000 $10,000,000 $700,000 $6,500,000

Maximum Reference Low Import $22,40 0,000 $76,100,000 $5,500,000 $49,300,000

Mean, w/o Upper Liner Reference Nuclear $3,300,000 $11,100,000 $800,000 $7,300,000

In addition to the annualized capita l and installation costs, the tota l annual cost includes the costs associated with the operation and maintenance (O &M) of the double liner. For the double liner, O&M would consist of daily inspecti on of the liner and repair of th e liner when rips or tears are

observed above the water level or wh en water is detected in the l eak detection layer. Since daily inspections of the nonconventi onal impoundments are part of the routine operation of the uranium recovery facility (Visus 2009), the only additional O&M cost associated with the double liner would be the repair costs. It was assumed that the annual O&M cost for the nonconventional impoundments would be 0.5% of the total capital cost for installing the liners (MWH 2008 and Poulson 2010). Using the Table 33 ba se facility cost estimates for installation of the double liner, Table 36 shows the calculated double liner O&M costs for each base facility.

Table 36: Base Facility Nonconventional Impoundment Double Liner Annual Operation and Maintenance Costs

Cost Type O&M

Allowance Base Facility Annual O&M Cost ($/yr)

Conventional ISR Heap

Mean 0.5% $68,000 $120,000 $13,000

Median 0.5% $56,000 $100,000 $11,000

Minimum 0.25% $16,000 $29,000 $3,200

Maximum 1.0% $330,000 $590,000 $65,000

Mean, w/o Upper Liner 0.5% $34,000 $61,000 $6,700

Table 37 shows annual O&M co sts for the projected 2035 U 3 O 8 productions. The Table 37

annual O&M costs were calculated by dividing the Table 36 costs by each base facility’s annual

U 3 O 8 production and then multiplying by the projected 2035 U 3 O 8 production.99 Table 37: Projected Nonconventional Impoundment Double Liner Annual Operation and Maintenance Costs

Cost Type Projected 2035

U 3 O 8 Production Annual Operation and Maintenance Cost ($/yr)

Conventional ISR Heap Mix

Mean Reference Nuclear $1,300,000 $990,000 $50,000 $1,100,000

Median Reference Nuclear $1,100,000 $830,000 $39,000 $950,000

Minimum Low Nuclear Production $300,000 $230,000 $11,000 $250,000

Maximum Reference Low Import $9,000,000 $6,900,000 $330,000 $7,600,000

Mean, w/o Upper Liner Reference Nuclear $700,000 $500,000 $24,000 $560,000

The total annual cost for a double liner in a non conventional impoundment is simply the sum of the annualized capital (Table 35) and installation cost plus th e annual O&M cost (Table 37).

Table 38 shows these total annual costs for the five cost t ypes and four assumed uranium recovery facility cases.

Table 38: Projected Nonconventional Im poundment Double Liner Total Annual Costs

Cost Type Projected 2035

U 3 O 8 Production Total Annual Cost ($/yr)

Conventional ISR Heap Mix

Mean Reference Nuclear $8,000,000 $23,700,000 $1,700,000 $16,000,000

Median Reference Nuclear $6,700,000 $19,800,000 $1,400,000 $13,300,000

Minimum Low Nuclear Production $3,200,000 $10,200,000 $700,000 $6,800,000

Maximum Reference Low Import $31,40 0,000 $83,000,000 $5,800,000 $56,900,000

Mean, w/o Upper Liner Reference Nuclear $3,900,000 $11,700,000 $800,000 $7,800,000

Section 6.2, Table 18 (page 75), shows that the to tal estimated cost to produce all of the U 3 O 8 projected for 2035 by the Reference Nuclear pr ojection. Table 39 compares those total U 3 O 8 production costs to the double liner total costs given in Table 38. As Table 39 shows, the cost to

install a double liner is less than 6% of the total cost to produce U 3 O 8 , while the cost to upgrade from a single liner to a double liner is less than 3% of the total cost.

Table 39: Comparison of Double Liner to Total U 3 O 8 Production Costs

Facility Type 2035 Projection Reference Nuclear Cost (million 2011$) Liner

Contribution

Total Annual

(Table 18) Double Liner (Table 38) Single to Double (Table 38) Double

Liner Single to

Double

Conventional $398 $8.0 $3.9 2.0% 1.0%

In-Situ Leach $411 $23.7 $11.7 5.8% 2.8%

Heap Leach $356 $1.7 $0.8 0.5% 0.2%

Mixed Facilities $396 $16.0 $7.8 4.0% 2.0%

Finally, the conventional, ISR, and heap leach ba se uranium recovery f acilities (see Section 6.2) include a double liner, with drainage layer (Geonet) collection system for their onsite100 impoundment designs. Thus, there is no additional cost for th e Section 6.2 base uranium recovery facilities to meet th e design and construction requi rements at 40 CFR 192.32(a)(1) for

onsite nonconventi onal impoundments.

Benefits from a Double Liner for a Nonconventional Impoundment

Including a double liner in the design of all onsite nonconventi onal impoundments that would contain uranium byproduct materi al would reduce the potential for ground water contamination. Although the amount of th e potential reduction is not quantif iable, decision makers should

consider this benefit because of the significance of ground water as a source of drinking water.

6.3.3 Maintaining 1 Meter of Water in Nonconventional Impoundments

As shown in Section 3.3.1, as long as a depth of a pproximately 1 meter of water is maintained in the pond, the effective radon emissions from the pond are so low that it is difficult to determine if there is any contribution a bove background radon values. This se ction estimates the cost to maintain 1 meter of water in the impoundment.

In order to maintain 1 meter, or any level, of water within a pond it is necessary to replace the water that is evaporated from the pond. If the evaporated water is not replaced by naturally occurring precipitation, then it would need to be replaced with makeup water supplied by the pond’s operator. The replacement process is assume d to be required as part of the normal operation of the uranium recovery facility, which would occur regardless of the GACT. Thus,

this cost estimate does not incl ude process water replacement.

Unit Cost of Water

Three potential sources of pond makeup water we re considered: municipal water suppliers, offsite non-drinking-water s uppliers, and ons ite water.

Municipal Water Supplier (Black & Veatch 2010)

― In 2009/2010, a survey of the cost of water in the 50 largest U.S. c ities was performed (Black & Ve atch 2010). The survey compiled typical monthly bill data for three re sidential (3,750, 7,500, and 15,000 gallon/month), a commercial (100,000 gallon/month), and an indus trial (10,000,000 gallon/month) water users. For this study, the commercial and industrial data were normalized to dollars per gallon, and the higher of the two values was used.

The survey found that the cost of water ranged from $0.0012 gallon -1 in Sacramento, California, to $0.0066 gallon -1 in Atlanta, Georgia, with a mean of $0.0031 gallon -1 and a median of $0.0030 gallon -1 . Looking at only those cities located with in states potentiall y producing uranium (i.e., Arizona, Colorado, New Me xico, and Texas; the survey in cluded no cities in Utah or Wyoming), the survey found that the cost of water ranged from $0.0016 gallon -1 in Albuquerque, New Mexico, to $0.0045 gallon -1 in Austin, Texas, with a mean and median of $0.0031 gallon -1

.

Offsite Non-Drinking-Water Suppliers (DOA 2004)

― The water supplied by municipal water suppliers has been treated and is suitable fo r human consumption. It is not necessary for101 impoundment evaporation makeup water to be dri nking water grade. Theref ore, using the data from the 50-city survey would likely overe stimate the impoundment makeup water cost. Unfortunately, no data could be found as to the co st of non-drinking-water grade water for use as impoundment makeup water. However, another large scale use of non- drinking-water grade water is for crop irrigation, and the U.S. Departme nt of Agriculture has compiled data on the cost of irrigation water for crops (DOA 2004).

For offsite sources of irrigation water, the Depart ment of Agriculture states that the “31.6 million

acre-feet of water received from off-farm wate r suppliers ... cost irrigators $579 million, for an average cost of $18.29 per acre -foot of water ...” (DOA 2004, page XXI), or $0.000056 gallon -1

.

Onsite Water (DOA 2004)

― The Department of Agriculture id entifies both wells (43.5 million acre-feet) and surface water (11.8 mil lion acre-feet) as sources of onsite water. The cost for both sources is essentially the cost to pump the water from its source to where it is used. Unfortunately, the Department does not provide separate pumping costs fo r each onsite source,

but instead states:

There were 497,443 irrigation pumps of all kinds used on 153,117 farms in 2003 irrigating 42.9 million acres of land. Th ese pumps were powered by fuels and electricity costing irriga tors a total of $1.55 billion or an average of $10,135 per farm. The principal energy source used was electricity, for which $953 million was spent to power 319,102 pumps that irrigated 24.1 million acres at an average cost of $39.50 per acre. Solar energy was reported as the source for pumping wells on 360 farms irrigating 16,430 acres. [DOA 2004, page XXI]

From these data, it is possible to determine th at the mean cost for pumping onsite water from both sources is $0.000086 gallon -1 . Also, on a per acre basis, the co st of using electricity to pump the water is slightly higher th an the total average cost (i.e., $39.50 versus $36.13), and the use of solar energy to pump water is ve ry rare (i.e., only about 0.03%).

Unit Costs

― Table 40 shows the makeup water unit costs that have been estimated for this study. As described, the municipal water sour ce costs are taken from Black & Veatch 2010, while the mean costs for offsite non-drinking and onsite water sources were taken from DOA 2004. All unit water costs were adjusted to 2011 dollars.

Although the Department of Agriculture did not present sufficient data to allow for the calculation of minimum, maximum, and median un it water costs, these costs were estimated by assuming that the cost of offsite non-drinking an d onsite water sources have variation in costs

similar to the variation in muni cipal supplier costs. Table 40 al so shows these estimated makeup

water unit costs.102 Table 40: Makeup Water Unit Costs

Area Source Makeup Water Unit Costs (gallon -1 )

Minimum Mean Median Maximum

United States Municipal Supplier $0.0013 $0.0033 $0.0032 $0.0069

Offsite Non-Drinking $0.000027 $0.000069 $0.000067 $0.000144

Onsite Source $0.000041 $0.00011 $0.00010 $0.00022

Potential Uranium Producing States (AZ, CO, NM, TX) Municipal Supplier $0.0017 $0.0032 $0.0033 $0.0047

Offsite Non-Drinking $0.000035 $0.000068 $0.000068 $0.000099

Onsite Source $0.000054 $0.00010 $0.00010 $0.00015

Additionally, Edge (2009) presents the discounted cost of estimated consumptive water use for the Piñon Ridge conventional mill. With 3% and 7% discount rates, the 40-year cost of water was presented as $58,545 and $33,766, respectively, wh ich translates into an annual cost of $2,533. Edge (2009, page 7-2) indicates that the Piñon Ridge mill is estimated to use 227 acre-feet of water per year . This gives a water unit cost of $0.000034, which is consistent with the Table 40 offsite non-drinking and onsite water sources unit costs.

Total Annual Cost to Maintain 1 Meter of Water

Required Water Makeup Rate (Net Evaporation Rate)

― As stated above, in order to

maintain the water level within a nonconventio nal impoundment, it is necessary to replace the water that is evaporated from the impoundment. So me (and in some places all) of the evaporated water will be made up by naturally occurr ing precipitation. Figure 17 shows the annual evaporation (inches per year (in/yr)) of the lo wer 48 states, while Figure 16 shows the annual precipitation (in/yr). To determ ine the annual required water ma keup rate, the Figure 16 data is simply subtracted from the Figure 17 data. A posi tive result indicates that evaporation is greater than precipitation, and makeup water must be supp lied, whereas a negative re sult indicates that precipitation is sufficient to main tain the impoundment’s water level.

The U.S. Army Corps of Engineers (ACE) has pub lished net lake evaporation rates for 152 sites located in the United States (ACE 1979, Exhib it I). The ACE found that the net evaporation ranged from -35.6 in/yr in North Head, Washingt on, to 96.5 in/yr in Yuma, Arizona, with a mean of 10.8 in/yr and a median of 0.9 in/yr. At 82 site s, the evaporation rate exceeds the precipitation rate, and makeup water would be required to maintain the impoundment’s water level.

Looking at only those 22 sites located within states potentially producing ur anium (i.e., Arizona, Colorado, New Mexico, Texas, Utah, and Wyomi ng), the ACE found that the net evaporation rate ranged from 6.1 in/yr in Houston, Texas, to 96.5 in/yr in Yuma, Ar izona, with a mean of 45.7 in/yr and a median of 41.3 in/yr. The evapora tion rate exceeded the pr ecipitation rate at all 22 sites in the potentially uranium-pr oducing states included in the ACE study.

Uranium Recovery Facility Pond Size

― As described in Section 6.2, a base facility was assumed for each of the three types of uranium rec overy facilities. Table 41 gives information for each base facility that is nece ssary to calculate the annual makeup water cost (i.e., the surface area of the onsite impoundments and the annul U 3 O 8 production).103 Table 41: Summary of Base Facility Characteristics

Parameter Conventional ISR Heap
Impoundment Surface Area (acres) 41.3 75.3 8.1

U 3 O 8 Production (lb/yr) 400,000 930,000 2,200,000

Total Annual Cost

― The only cost associated with maintaining the water level within the impoundment is the cost of the water. It is assumed that existing piping will connect the nonconventional impoundment to the water source, a nd that the water level will be visually checked at least once per day (Visus 2009).

The makeup water unit cost data from Table 40, the net evaporation rates from above (page 102), and the impoundment areas from Table 41 are comb ined to calculate annual makeup water cost estimates provided in Table 42.

Table 42: Base Facility Annual Makeup Water Cost

Cost Type Water Cost ($/gal) Net Evaporation (in/yr) Makeup Water Cost ($/yr)

Conventional ISR Heap

Mean $0.00010 45.7 $5,313 $9,687 $1,042

Median $0.00010 41.3 $4,840 $8,826 $949

Minimum $0.000035 6.1 $240 $438 $47

Maximum $0.00015 96.5 $16,337 $29,790 $3,204

The annual cost of makeup water from Tabl e 42 was divided by the base facility U 3 O 8 annual production rate from Table 41 to calculat e the makeup water cost per pound of U 3 O 8 produced,

shown in Table 43.

Table 43: Base Facility Makeup Water Cost per

Pound of U 3 O 8

Cost Type Makeup Water Cost ($/lb)

Conventional ISR Heap

Mean $0.0133 $0.0104 $0.00047

Median $0.0121 $0.0095 $0.00043

Minimum $0.00060 $0.00047 $0.000021

Maximum $0.041 $0.032 $0.0015

Section 6.2.6 (Table 25) provi ded projections of the U 3 O 8 requirements in the year 2035 for four different nuclear usage scenar ios: Reference Nuclear – 7,728,000 lb; Low Nuclear Production – 7,277,000 lb; High Nuclear Production – 9,302,000 lb; and Reference Low Import – 10,862 lb. Table 44 shows the makeup water costs which were calculated for the U 3 O 8 production projected

for 2035. The first three cost estimates assume that a single type of uran ium recovery facility would be responsible for produc ing all of the projected U 3 O 8 , while the last estimates assume that a mix of uranium recovery type facili ties is used, as described in Section 6.2.6.104 Table 44: Projected Annual Makeup Water Cost

Cost Type Projected 2035

U 3 O 8 Production Makeup Water Cost ($/yr)

Conventional ISR Heap Mix

Mean Reference Nuclear $102,630 $80,489 $3,660 $88,979

Median Reference Nuclear $93,500 $73,329 $3,334 $81,063

Minimum Low Nuclear Production $4,366 $3,424 $156 $3,780

Maximum Reference Low Import $443,678 $347,963 $15,821 $381,053

Table 18 (page 75) shows the total estim ated cost to produce all of the U 3 O 8 projected for 2035 by the Reference Nuclear projections . Table 45 compares those total U 3 O 8 production costs to the costs for maintaining 1 meter of water in the impoundments given in Table 44. As Table 45 shows, the cost to maintain 1 meter of water in the impoundments is much less than 1% of the total cost to produce U 3 O 8 for all four cases analyzed.

Table 45: Comparison of Cost to Maintain 1 Meter of Water in the Impoundments to Total U 3 O 8 Production Cost

Facility Type 2035 Projection Reference Nuclear Cost (million 2011$) 1 Meter Water

Contribution Total Annual

(Table 18) 1 Meter Water (Table 44)

Conventional $398 $0.103 0.026%

In-Situ Leach $411 $0.080 0.019%

Heap Leach $356 $0.004 0.001%

Mixed Facilities $396 $0.089 0.022%

Total Annual Benefits from Maintaining 1 Meter of Water

By requiring a minimum of 1 meter of water in all nonconventional impou ndments that contain uranium byproduct material, the release of ra don from these impoundments would be reduced. Nielson and Rogers (1986) pr esent the following equation for calculating the radon attenuation:

ܣ ൌ ݁ ቆ

ି ൤ ఒ

஽ ൨ బ.ఱ ௗ ቇ (6-1) Where: A = Radon attenuation factor (unitless)

λ

= Radon-222 decay constant (sec -1 )

= 2.1×10 -6 sec -1 D = Radon diffusion coefficient (cm 2 /sec)

= 0.003 cm 2 /sec in water d = Depth of water (cm)

= 100 cm

Solving the above equation shows that 1 meter of water has a radon attenu ation factor of about 0.07. To demonstrate the impact that a 1-meter water cover would have, the doses and risks reported in Section 4.4, Table 13 (p age 49), have been recalculate d. In this recalculation, it was

assumed that an additional 1 meter of water cove red all of the radon sources. Table 46 shows the results of this recalculation, in terms of the dose and ri sk reduction attributable to covering the105 source area with 1 meter of water. Table 46 show s both the original radon release (as reported in Table 13, page 49) and the radon release after the source area has been covered with 1 meter of

water.

Table 46: Annual Dose and Ri sk Reduction from Maintainin g 1 Meter of Water in the Impoundments

Uranium Site Radon Release (Ci/yr) Annual Dose

Reduction LCF (a) Risk Reduction (yr -1 )

Table 13 1 Meter

Water Population (person-rem) RMEI (mrem) Population RMEI

Sweetwater 2,075 147 0.5 1.1 2.7E-06 5.6E-07

White Mesa 1,750 124 4.8 11.1 3.2E-05 5.9E-06

Smith Ranch - Highlands 36,500 2,590 3.4 1.4 2.1E-05 7.2E-07

Crow Butte 8,885 630 2.5 3.1 1.6E-05 1.6E-06

Christensen/Irigaray 1,600 114 3.5 1.8 2.2E-05 9.2E-07

Alta Mesa 740 52 20.1 10.7 1.2E-04 5.7E-06

Kingsville Dome 6,958 494 53.9 10.5 3.5E-04 5.7E-06

* LCF = latent cancer fatalities

6.3.4 Liners for Heap Leach Piles

Designing and constructing heap leach piles to meet the requirements at 40 CFR 192.32(a)(1) would minimize the potential for leakage of uranium enriched lixiviant into the ground water. Specifically, this would require that a double liner, with draina ge collection capabilities, be provided under heap piles. Figure 26 shows a typi cal design of a heap leach pile double liner. Although Figure 26 shows a clay-amended layer bene ath the double liner, for the reasons given in Section 6.3.2, this cost estimate has assume d that a GCL would be used beneath the double liner, as shown in Figure 24.106 Source: Titan 2011 Figure 26: Typical Heap Pile Liner

Double Liner Unit Costs

The unit costs for installing a double liner, with a leakage collection system, to a heap leach pile

are assumed to be the same as the units co sts developed in Section 6.3.2 for nonconventional impoundments.

The base heap leach facility utilizes a conveyor to deliver crushed material to the pile (Titan 2011). However, if material is delivered to the pile by truck, th en the truck would put

additional stress on the liner. Additional costs woul d be incurred to protect the liner from the additional stress. Because this analysis uses a ra nge of liner unit costs, the additional costs for protecting the liner if truck loading is employed have been enveloped.

Total Cost of Heap Leach Pile Double Liner

Section 6.2.2 base heap leach facility (i.e., Sheep Mountain in Wyoming) includes two 80-acre heap piles. Using the same method described for the nonconventional impoundment (page 96), it

was estimated that 90.3 acres of material woul d be required for the upper liner and drainage (Geonet) layer, and 89.6 acres of material for th e lower liner and GCL. Wi th these quantities of material and the unit costs from Section 6.3.2, Table 47 presents the median, minimum, and maximum capital and installation costs for inst alling the double liner be neath the two 80-acre heap piles.107 Table 47: Heap Pile Double Liner Capital and Installation Costs

Cost Type Capital and

Installation Cost

Mean $25,200,000

Median $20,600,000

Minimum $11,900,000

Maximum $60,700,000
Mean, w/o Upper Liner $12,900,000

Table 47 includes capital and annual cost estimates for a Mean, w/o Upper Liner case. This case was added because even if not required to m eet the requirements at 40 CFR 192.32(a)(1), the design of the heap leach pile woul d include at least a single liner to collect the lixiviant flowing out of the heap. The reason is th at since the lixiviant flowing out of the heap contains the uranium, it is in the licensee’s economic interest to recover as much of it as possible, and since the rinsing liquid would be mixed with the lixiv iant, it too would be recovered. Thus, the Mean, w/o Upper Liner case estimates the cost to upgrad e a single liner to a double liner system (i.e., the cost of the upper liner and the GCL have been removed).

To demonstrate the individual component contribu tion to the total capita l and installation cost, Table 48 presents a breakdown by component of the calculated mean capital and installation

cost.

Table 48: Mean Heap Pile Double Liner Capital Cost

Breakdown

Liner Component Unit Cost (ft -2 ) Mean Heap Pile Double Liner Capital Cost
Upper Liner $0.95 $3,730,077
Drainage (Geonet) $0.64 $2,505,687
Lower Liner $0.95 $3,702,230
GCL $0.66 $2,579,315
Design & Engineering 20% $2,503,462
Contractor Oversight 20% $2,503,462
Overhead & Profit 20% $3,504,847
Contingency 20% $4,205,816

Total

― $25,234,896

Table 49 presents the heap pile double liner annual cost estimates. The total annual cost is the sum of the annualized capital a nd installation cost and the annual O&M cost. The annualized capital cost was calculated by first dividing th e capital cost of the double liner by the total

amount of U 3 O 8 expected to be produced during the life time of the heap leach facility, and then multiplying by the amount of U 3 O 8 produced annually. The U 3 O 8 annual production was based on 2035 projections made in Section 6.2.6.108 Table 49 presents two cases. In the first case, it was assumed that all of the U 3 O 8 required in 2035 would be produced by heap leach facilities, while in the second case, it was assumed that heap leach facilities would be part of a mixtur e of uranium recovery facilities operating in 2035. For the second case, Table 25 gives the heap leach facility contribution to the total U 3 O 8 required

in 2035.

Table 49: Heap Pile Do uble Liner Annual Costs

Case Cost Type Annualized Capital Cost Annual O&M

Cost Total Annual

Cost Heap Only Mean $15,100,000 $220,000 $15,300,000

Median $12,300,000 $180,000 $12,500,000

Minimum $6,700,000 $60,000 $6,800,000

Maximum $51,100,000 $1,340,000 $52,400,000
Mean, w/o Upper Liner $7,700,000 $110,000 $7,800,000

Mix Mean $340,000 $5,000 $350,000

Median $280,000 $4,000 $280,000

Minimum $160,000 $1,000 $160,000

Maximum $1,600,000 $43,000 $1,600,000
Mean, w/o Upper Liner $170,000 $3,000 $170,000

Table 18 (page 75) shows that the total es timated cost to produce all of the U 3 O 8 projected for 2035 by the Reference Nuclear projection is $356 million. Thus, the cost for installing a double liner under the heap leach pile is about 4% of the total cost of heap leach U 3 O 8 production (i.e., $15.3 million/$356 million), while the cost to ch ange from a single liner to a double liner is about 2% of the total cost of heap leach U 3 O 8 production (i.e., $7.8 million/$356 million).

Finally, the Section 6.2.2 base heap leach facil ity design includes a double liner, with drainage layer (Geonet) colle ction system, as shown in Figure 26. Thus , there is no additional cost for the Section 6.2.2 base heap leach facility to m eet the design and construction requirements at 40 CFR 192.32(a)(1).

Benefits from a Double-Lined Heap Leach Pile

Including a double liner in the design of all heap leach piles would reduce the potential for ground water contamination. Although the amount of the potential reduction is not quantifiable, it is important for decision makers to consider this benefit because of the significance of ground water as a source of drinking water.

6.3.5 Maintaining Heap Leach Piles at 30% Moisture

As described in Section 5.4, the goal of this GACT is to maintain 30% moisture content in the heap leach pile so that the radon flux will be no larger than the flux from dry ore.

Simply adding water to the surface of the heap leach pile will replenish and maintain the moisture content in the surface layer. The moistu re content in the remainder of the heap leach109 vertical profile will be a functi on of the ore materials ability to retain moisture. The field moisture capacity of any earthen material is a f unction of the grain size a nd the mineralogy of the materials. Accordingly, the 30% moisture conten t should be attained w ith all low grade ore materials, due to the presence of significant fine -grained materials. Furthermore, it may not be necessary to maintain th e entire pile at 30% moisture cont ent, but only the upper portion of the pile. The exact depth to which the 30% moistu re content requirement would apply would be determined on a site by site basis. The cost to supply the water to replenish the pile’s moisture

content has been estimated below.

It is also recognized that im posing a 30% moisture content requirement on the pile might (and likely, would) require certain design changes to the pile. Principal concerns to be addressed during pile design are slope stability and the li quefaction potential. Re garding slope stability, many leach piles are provided with containment dikes which provide stru ctural support to the pile. The 30% moisture content requirement w ill have little or no effect on the moisture associated with the containment dikes, and thus the dikes would continue to provide support. Additionally, the pile design may be altered to increase its stability. For example, lower slopes, higher confinement dikes, the construction of stair-s tep pad grade, or the installation of textured (as opposed to smooth) geomembrane liner in cr itical areas would enha nce pile stability.

Regarding liquefaction potential, it has been estimated that liquef action is unlikely if the degree of saturation in the pile is less than about 85% (Sassa 1985, as referred to in Smith 2002, Thiel and Smith 2004). Assuming a 2.7 ratio between mo isture content and saturation (NRC 1984), the 30% moisture content require translates into 81% saturation, which is sl ightly below the level required for liquefaction. Needless to say, with the increase in the saturation that will result from the imposition of the 30% moisture content requirem ent, more attention will need to be paid to the pile design to minimize the liquefaction potential.

The costs associated with these design changes have not been included in the following cost estimate because any design change would depend ve ry much on the site’s characteristics, and in many cases the design change might be inexpensiv e to implement if it is identified during the design phase. For example, using a textured rather than smooth lin er, constructing higher containment dikes, and using stair-step pad grade could all be incorporated into the pile’s design at minimal, if any, additional cost.

Unit Water Cost

The unit costs for providing water to a heap leach pile are assumed to be the same as the unit costs developed in Section 6.3.3 (page 100) for providing water to nonconventional impoundments.

Cost of Soil Moisture Meters

Soil moisture sensors have been used for la boratory and outdoor tes ting purposes and for agricultural applications for over 50 years. They are mostly used to measure moisture in gardens and lawns to determine when it is appropriate to turn on irrigation systems. Soil moisture sensors can either be placed in the soil or held by hand.110 For example, one system would bury soil moisture sensors to the desire d depth in the heap. Then, a portable soil moisture meter would be conn ected by cable to each buried sensor one at a time, i.e., a single meter can read any number of sensors (Irrometer 2010). The portable soil moisture meter costs about $350, and each in-soil sensor about $35 or $45, depending on the length of the cable (either 5 or 10 ft) (Ben Meadows 2012).

Alternatively, with a handheld soil moisture meter, two rods ( up to 8 inches long) that are

attached to the meter are driven into the soil at the desired location, a nd a reading is taken. A handheld meter of this type costs about $1,065, and replacement rods about $58 for a pair (Spectrum 2011, Spectrum 2012).

Total Annual Cost to Maintain 30% Moisture in the Heap Leach Pile

The only cost associated with maintaining the mois ture level within the pi le is the cost of the water. It is assumed that existing piping (used to supply lixiviant to th e pile during leaching) would be used to supply water necessary for mainta ining the moisture level. Also, it is assumed

that the in-soil method for mois ture monitoring would be used, and that the above costs are insignificant. Finally, it is assumed that moisture readings would be performed during the daily inspections of the heap pile (Visus 2009), with no additional workhours.

The base heap leach facility includes a heap pile that will occupy up to 80 acres at a height of up to 50 ft. With an assumed porosity of 0.39 (see Se ction 5.1.5, page 56) and a moisture content of 30% by weight, the effective su rface area of the li quid within the heap pile is 33.7 acres.

Table 50 presents the calculated cost for makeup wa ter to maintain the moisture level in the heap pile, such that the moisture content is at 30% by weight, or greater. The unit costs for water and the net evaporation rates de rived in Section 6.3.3 were used for this estimate.

Table 50: Heap Pile Annual Makeup Water Cost

Cost Type Water Cost ($/gal) Net Evaporation (in/yr) Makeup Water Cost ($/yr) Makeup Water Rate (gpm/ft 2 )

Mean $0.00010 45.7 $4,331 2.3E-05

Median $0.00010 41.3 $3,946 2.1E-05

Minimum $0.000035 6.1 $196 3.0E-06

Maximum $0.00015 96.5 $13,318 4.8E-05

To place this amount of makeup water in perspec tive, during leaching and rinsing of the pile, liquid is dripped onto the pile at a rate of 0.005 gallons per minute per square foot (gpm/ft 2 ) (Titan 2011), or about 4,220 in/yr. This application rate is almost two orders of magnitude larger than the mean net evaporation rate, and is ove r a factor of 40 larger than the maximum net evaporation rate, shown in Tabl e 50, and should be sufficient to maintain the moisture content within the pile111 Section 6.2.6 and Table 25 (page 89) present projections of the U 3 O 8 production for the year 2035. Table 51 presents the annual cost for makeup water to maintain the heap pile’s moisture content. Table 51 presents two cases. In the first case, Heap Only, it was assumed that heap leach facilities would pr oduce all of the U 3 O 8 required in 2035, while in the second case, it was assumed that heap leach facilities would be part of a mixture of uranium recovery facilities operating in 2035. For the second case, Table 25 give s the heap leach facility contribution to the

total U 3 O 8 required in 2035.

Table 51: Projected Annual Heap Pile Makeup Water Cost

Cost Type Projected 2035

U 3 O 8 Production Makeup Water Cost ($/yr)

Heap Only Mix

Mean Reference Nuclear $15,000 $300

Median Reference Nuclear $14,000 $300

Minimum Low Nuclear Production $650 $20

Maximum Reference Low Import $66,000 $2,100

Table 18 (page 75) shows that the total es timated cost to produce all of the U 3 O 8 projected for 2035 by the Reference Nuclear projection is $356 million. Thus, the cost for maintaining 30% moisture in the heap leach pile is well under 1% of the total cost of heap leach U 3 O 8 production (i.e., $15,000/$356,000,000).

Total Annual Benefits from Maintaining 30% Moisture in the Heap Leach Pile

By requiring a minimum 30% by weight moisture c ontent in the heap leac h pile, the release of radon from these piles would be reduced by up to about a factor of 21⁄2, as shown in Figure 15. From the base case production profile (BRS 2011, pa ge 86), it can be determined that the heap pile ore has a mean U-238 concentration of 213 pCi/g, and a range of 135 to 321 pCi/g. Assuming the normalized radon flux from a heap pile with 30% moisture content is 1 pCi/(m 2 -sec) per pCi/g Ra-226, and that the Ra-226 is in equilibrium with the U-238, then the mean annual radon release from the 80-acre heap pile would be 2,180 Ci/yr. A comparable annual radon release from a drye r heap pile could be as high as 5,450 Ci/yr. Table 52 shows a comparison of annual doses and risks using these heap pile annual radon releases and the release to dose/risk relationship for the We stern Generic site from Table 13.

Table 52: Annual Dose and Risk Comparison for Maintaining 30% Moisture Content in the Heap Pile

Heap Pile

Moisture Content (by Weight) Radon

Release (Ci/yr) Annual Dose LCF (a) Risk (yr -1 )

Population (person-rem) RMEI (mrem) Population RMEI

>30% 2,180 6.3 7.5 3.4E-04 9.6E-06

<30% 5,450 16 19 8.4E-04 2.4E-05

* LCF = latent cancer fatalities112 Of course the exact reduction wi ll depend upon the specific heap pile. For example, if a heap pile is operating at 20% moisture content without the GACT, then according to Figure 15, imposing

the GACT would result in a radon flux reduction of about a factor of 1.6. Also, as Figure 14 shows, the response of the radon emanation coeffici ent to increasing moisture is very dependent on the material. This relationship between the em anation coefficient, moisture content, and

material also influences the amount of reduction provided by the GACT.

6.3.6 Summary of Proposed GACT Standards Economic Assessment

Sections 6.3.2 through 6.3.5 presents the details of the economic assessment that was performed for implementing each of the four proposed GACT standards. Table 53 presents a summary of the unit cost (per pound of U 3 O 8 ) for implementing each GACT at each of the three types of uranium recovery facilities. In addition to presenting the GACT costs individually, Table 53 presents the total unit cost to implement al l relevant GACTs at each type of facility.

A reference facility for each t ype of uranium recovery facility is developed and described in Section 6.2, including the base cost estimate to construct and operate (w ithout the GACTs) each of the three types of reference facilities. For comparison purposes, the un it cost (per pound of

U 3 O 8 ) of the three uranium recovery reference facilities is presented at the bottom of Table 53

.

Table 53: Proposed GACT Standards Costs per Pound of U 3 O 8

Unit Cost ($/lb U 3 O 8 )
Conventional ISL Heap Leach

GACT – Double Liners for Nonconventional Impoundments $1.04 $3.07 $0.22

GACT – Maintaining 1 Meter of Water in Nonconventional Impoundments $0.013 $0.010 $0.0010

GACT – Liners for Heap Leach Piles

― ― $2.01
GACT – Maintaining Heap Leach Piles at

30% Moisture ― ― $0.0043

GACTs – Total for All Four $1.05 $3.08 $2.24
Baseline Facility Costs (Section 6.2) $51.56 $52.49 $46.08

Based on the Table 53 , implementing all four GACTs would result in unit cost (per pound of

U 3 O 8 ) increases of about 2%, 6%, and 5% at conve ntional, ISL, and heap leach type uranium recovery facilities, respectively.

Included in the Section 6.2 desc riptions is the operational duration and amount of uranium produced by each reference facility. This informa tion from Section 6.2 has been used to calculate

an annual U 3 O 8 production rate for each type facility, wh ich in turn has been coupled with the unit costs provided in Table 53 , to generate the annual cost for implementing each GACT at each reference facility. These annual costs are presented in Table 54 . Again for comparison the baseline cost (without the GACTs ) is provided at the bottom of Table 54 for each type facility.113 Table 54: Proposed GACT Standards Reference Facility Annual Costs

Reference Facility Annual Cost ($/yr)
Conventional ISL Heap Leach

GACT – Double Liners for Nonconventional Impoundments $410,000 $2,900,000 $230,000

GACT – Maintaining 1 Meter of Water in Nonconventional Impoundments $5,300 $9,700 $1,100

GACT – Liners for Heap Leach Piles

― ― $2,100,000 GACT – Maintaining Heap Leach Piles at

30% Moisture ― ― $4,500

GACTs – Total for All Four $420,000 $2,900,000 $2,300,000
Baseline Facility Costs $21,000,000 $49,000,000 $48,000,000

Based on EIA (EIA 2011a) nuclear power produ ctions, Section 6.2.6 estimated the U.S. U 3 O 8 productions until the year 2035. Using those EI A-based production estimates for 2011 and 2035

and the unit cost values from Table 53

, Table 55 presents the estimated national annual cost for implementing the proposed GACTs.

Table 55: Proposed GACT Standards National Annual Costs

National Annual Cost ($1,000/yr)

2011 U 3 O 8 Production
Conventional ISL Heap Leach Total

GACT – Double Liners for Nonconventional Impoundments $3,500 $12,000 $0 $15,000

GACT – Maintaining 1 Meter of Water in Nonconventional Impoundments $45 $40 $0 $85

GACT – Liners for Heap Leach Piles

― ― $0 $0 GACT – Maintaining Heap Leach Piles at

30% Moisture ― ― $0 $0

GACTs – Total for All Four $3,600 $12,000 $0 $15,000
Baseline Facility Costs $180,000 $200,000 $0 $380,000

2035 U 3 O 8 Production
Conventional ISL Heap Leach Total

GACT – Double Liners for Nonconventional Impoundments $3,300 $11,000 $230 $14,000

GACT – Maintaining 1 Meter of Water in Nonconventional Impoundments $42 $37 $1.1 $80

GACT – Liners for Heap Leach Piles

― ― $2,100 $2,100
GACT – Maintaining Heap Leach Piles at

30% Moisture ― ― $4.5 $4.5

GACTs – Total for All Four $3,300 $11,000 $2,300 $17,000
Baseline Facility Costs $160,000 $190,000 $48,000 $400,000

Since no facilities were operating, it was assumed that all 2011 U 3 O 8 production was divided

between conventional and ISL fac ilities with the 2009 ratio, as shown in Table 25 (i.e., 47.3% conventional and 52.7% ISL). As described in Section 6.2.6, for 2035 it was assumed that one114 heap leach facility would be operationa l, and that the remainder of the U 3 O 8 production would be

divided between conventional and IS L facilities with the 2009 ratio.

Of course, if the amount of U 3 O 8 produced by each type facility changes the annual cost to implement the GACTs changes as well. For example if in 2035 all U 3 O 8 is produced by ISL facilities, then the national annual cost to implement the GACTs would increase from $17 million (as shown in Table 55 ) to $24 million. Altern atively, if all 2035 U 3 O 8 is produced by conventional facilities, then the national annual cost to implemen t the GACTs would decrease to
$8.1 million. Because the baseline U 3 O 8 production costs are fairly cons tant across all three types of uranium recovery facilities (see Table 53 and Sections 6.2.1 through 6.2.4), the 2035 baseline

U 3 O 8 production national annual cost would rema in fairly constant around $400 million, regardless of how the U 3 O 8 is produced.

Table 56 presents the national cost for the implem entation of the four proposed GACTs summed over the years 2011 to 2035. As with the Table 55 annual national costs, the Table 56 summed national costs are based on EIA (EIA 2011a) nuclear power productions, as described in Section

6.2.6.

Table 56: Proposed GACT Standards Summed National Costs

National Cost, Summed from 2011 to 2035 ($1,000)

Non-Discounted
Conventional ISL Heap Leach Total

GACT – Double Liners for Nonconventional Impoundments $81,000 $270,000 $5,800 $350,000

GACT – Maintaining 1 Meter of Water in Nonconventional Impoundments $1,000 $910 $27 $2,000

GACT – Liners for Heap Leach Piles

― ― $52,000 $52,000
GACT – Maintaining Heap Leach Piles at

30% Moisture ― ― $110 $110

GACTs – Total for All Four $82,000 $270,000 $58,000 $410,000
Baseline Facility Costs $4,000,000 $4,600,000 $1,200,000 $9,800,000

Discounted @3%
Conventional ISL Heap Leach Total

GACT – Double Liners for Nonconventional Impoundments $58,000 $190,000 $4,100 $250,000

GACT – Maintaining 1 Meter of Water in Nonconventional Impoundments $740 $650 $19 $1,400

GACT – Liners for Heap Leach Piles

― ― $37,000 $37,000
GACT – Maintaining Heap Leach Piles at

30% Moisture ― ― $80 $80

GACTs – Total for All Four $59,000 $190,000 $41,000 $290,000
Baseline Facility Costs $2,900,000 $3,300,000 $850,000 $7,000,000115 Table 56: Proposed GACT Standards Summed National Costs

National Cost, Summed from 2011 to 2035 ($1,000)

Discounted @ 7%
Conventional ISL Heap Leach Total

GACT – Double Liners for Nonconventional Impoundments $40,000 $130,000 $2,900 $170,000

GACT – Maintaining 1 Meter of Water in Nonconventional Impoundments $510 $450 $13 $970

GACT – Liners for Heap Leach Piles

― ― $26,000 $26,000 GACT – Maintaining Heap Leach Piles at

30% Moisture ― ― $55 $55

GACTs – Total for All Four $41,000 $130,000 $29,000 $200,000
Baseline Facility Costs $2,000,000 $2,300,000 $590,000 $4,800,000

As with the Table 55 annual national costs, if the amount of U 3 O 8 assumed to be produced by each type facility changes the Table 56 summed national costs to implement the GACTs changes as well. For example if all U 3 O 8 is produced by ISL facilities, then the non-discounted summed national cost to implement the GACTs w ould increase from $410 million (as shown in Table 56 )
to $590 million. Altern atively, if all U 3 O 8 is produced by conventiona l facilities, then the nondiscounted summed national cost to implem ent the GACTs would decrease to $200 million.

Similar to the baseline annual na tional costs, the baseline U 3 O 8 production non-discounted

summed national cost would remain ar ound $9.8 billion, regardless of how the U 3 O 8 is produced.

6.4 Environmental Justice

Concerning environmental justice, EPA’ s economic assessment guidelines state:

Distributional analyses address the im pact of a regulation on various subpopulations. Minority, low-income and tr ibal populations may be of particular concern and are typically addressed in an environmental justice (EJ) analysis. Children and other groups may also be of concern and warrant special attention in a regulatory impact analysis. [EPA 2010, Section 10]

6.4.1 Racial Profile for Uranium Recovery Facility Areas

This section presents information on the racial (e.g., tribal populati ons) and economic (e.g., low income) profiles of the areas su rrounding existing and proposed ur anium recovery facilities.

Table 57 presents the racial profiles in the immediate areas (i.e., counties) surrounding the existing and proposed uranium recovery facilities , while Table 58 presents the profiles in the surrounding regional area (i.e., states) and on a national basis. A comparison of Table 57 to

Table 58 indicates whether the racial population profile surr ounding the uranium recovery

facilities conform to the na tional and/or regional norms.116 Table 57: Racial Profile for Uran ium Recovery Facility Counties

Existing/Proposed Facility Facility Type County, State White Black Native

American Others

Juan Tafoya Conventional McKinley, NM 22.2% 0.4% 75.4% 2.0%

White Mesa Mill Conventional San Juan, UT 42.7% 0.1% 55.8% 1.3%
Grants Ridge Heap Leach Cibola, NM 56.2% 1.0% 40.9% 1.8%
Sheep Mountain Heap Leach Fremont, WY 78.3% 0.1% 19.8% 1.8%

Crow Butte In-Situ Leach Dawes, NE 94.5% 0.9% 3.0% 1.6%
Piñon Ridge Conventional Montrose, CO 96.6% 0.4% 1.4% 1.7%

Sweetwater Mill Conventional Sweetwater, WY 96.3% 0.8% 1.1% 1.9%
Christensen / Irigaray In -Situ Leach Campbell, WY 97.4% 0.2% 1.0% 1.4%
Smith Ranch - Highland In-Situ Leach Converse, WY 97.5% 0.1% 1.0% 1.4%
Shootaring Canyon Conventional Garfield, CO 97.2% 0.5% 0.8% 1.6%
Kingsville Dome In-Situ Leach Kleberg, TX 92.8% 3.9% 0.8% 2.6%

Goliad In-Situ Leach Goliad, TX 93.6% 5.0% 0.7% 0.7%
Palangana In-Situ Leach Duval, TX 98.3% 0.6% 0.7% 0.4%

Alta Mesa In-Situ Leach Brooks, TX 98.8% 0.4% 0.6% 0.3%
Source: http://www.census.gov/popest/counties/asrh/

Table 58: Regional and National Racial Profiles

State White Black Native

American Others

New Mexico NM 85.4% 2.1% 9.8% 2.7%

Wyoming WY 95.1% 0.8% 2.3% 1.8%

Utah UT 94.0% 0.9% 1.4% 3.7%

Colorado CO 90.7% 4.0% 1.2% 4.1%

Nebraska NE 92.7% 4.1% 0.9% 2.3%

Texas TX 83.7% 11.8% 0.7% 3.9%

United States US 81.1% 12.7% 0.9% 5.3%

Source: http://www.census.gov/popest/counties/asrh/

At 10 of the 15 sites, the percentage of Nativ e Americans in the populat ion exceeds the national norm, while at nine sites, th e percentage of Native Americans in the population exceeds the regional norm. At 11 of the 15 si tes, the percentage of the popul ation that is White exceeds both the national and regional norms. Fi nally, the percentage of the popul ation at all uranium recovery

sites that is either Black or Other is less than the national norm, while the percentage of Blacks and Others is less than the regi onal norm at all but one site.

For all of the sites considered together, the data in Table 57 do not reve al a disproportionately high incidence of minority populatio ns being located near uranium recovery facilities. However, certain individual sites may be located in ar eas with high minority populations. Those sites would need to be evaluated during th eir individual li censing processes.117 6.4.2 Socioeconomic Data for Uraniu m Recovery Facility Areas

Table 59 shows the socioeconomic data for the immediate areas (i.e., counties) surrounding the existing and planned uranium recovery facilities . Specifically, the socioeconomic data shown in

Table 59 is the fraction of land that is farmed, the value of that farmland, and the nonfarm per capita wealth. The percentages shown next to the value of that farmland and the nonfarm per capita wealth indicate where the site ranks when compared to all other counties in the United

States.

Table 59: Socioeconomic Data for Ur anium Recovery Facility Counties

Existing/Proposed Facility Facility Type County, State Farm

Land Farm Value

Per Hectare Per Capita

Nonfarm Wealth

White Mesa Mill Conventional San Juan, UT 31.1% $670 4.0% $103,073 0.6%

Juan Tafoya Conventional McKinley, NM 90.9% $185 0.0% $115,603 1.9%

Alta Mesa In-Situ Leach Brooks, TX 72.8% $1,423 13.2% $117,693 2.2%

Grants Ridge Heap Leach Cibola, NM 58.2% $378 0.7% $118,862 2.4%

Palangana In-Situ Leach Duval, TX 74.1% $1,792 17.5% $132,493 6.9%

Crow Butte In-Situ Leach Dawes, NE 88.0% $895 6.9% $144,291 15.1%

Kingsville Dome In-Situ Leach Kleberg, TX 0.0% $1,478 13.9% $149,865 20.4%

Goliad In-Situ Leach Goliad, TX 92.6% $2,244 22.0% $162,584 35.4%

Piñon Ridge Conventional Montrose, CO 23.3% $2,916 30.1% $181,133 59.5%

Sheep Mountain Heap Leach Fremont, WY 42.6% $768 5.3% $186,775 65.4%

Shootaring Canyon Conventional Garfield, CO 21.4% $3,195 34.3% $200,316 76.7%

Smith Ranch - Highland In-Situ Leach Conv erse, WY 92.5% $381 0.7% $208,583 82.1%

Christensen/Irigaray In-Situ Leach Campbell, WY 97.3 % $437 1.1% $225,858 89.3%

Sweetwater Mill Conventional Sweetwater, WY 22.2% $242 0.1% $232,504 91.2%

The discussion first focuses on the per capita nonfarm wealth. For co mparison, the per capita nonfarm wealth in the United States ranges from $39,475 (Slope County, North Dakota) to $618,954 (New York County, New York). Table 59 s hows that uranium rec overy facilities are located in areas that are very poor (i.e., ranked in the lowest 0.6% in the country) to areas that are very well to do (i.e., ranked in the 91.2 percentile). Six of the 15 sites are located in areas that have per capita nonfarm wea lth that is above the 50 th percentile in the United States. On the other hand, five sites are located in areas in which the per capita nonfarm wealth is below the country’s

10 th percentile.

Table 59 shows that eight of the sites have mo re than 50% of their land devoted to farming. However, the Table 59 farm value data show th at the farmland for all 15 sites is below the 35 th
percentile farmland value in the United States. Th is could indicate that the farmland is of poor quality, or simply that the land is located in an economically depressed area. For comparison, farmland in the United States ranges in valu e from $185 per hectare (McKinley County, New Mexico, which is the location of the proposed Juan Tafoya uranium r ecovery facility) to $244,521 per hectare (Richmond County, New York).118 For all of the sites combined, the data provided in Table 59 do not reveal a disproportionately high incidence of low-income populations being located near uranium recovery facilities. However, certain individual sites may be loca ted within areas of low-income population. Those

sites would need to be evaluated duri ng their individual licensing processes.

6.5 Regulatory Flexibility Act

The Regulatory Flexibility Act requires federal de partments and agencies to evaluate if and/or how their regulations impact small business entities . Specifically, the agency must determine if a regulation is expected to have a significant economic impact on a substantial number of small

entities. Small entities include small businesse s, small organizations, and small governmental jurisdictions.

If a rulemaking is determined to have a signif icant economic impact on a substantial number of small entities, then the agency must conduct a formal regulatory fl exibility analysis. However, if the agency determines that a rulemaking does not have a significant economic impact on a substantial number of small entities, then it make s a certification of that finding and presents the analyses that it made to a rrive at that conclusion.

To evaluate the significance of the economic impacts of the proposed revisions to Subpart W, separate analyses were performed for each of the three proposed GACTs.

The GACT for uranium recovery f acilities that use conventional milling techniques proposes that only phased disposal units or contin uous disposal units be used to manage the tailings. For either option, the disposal unit must be lined and equipp ed with a leak detection system, designed in accordance with 40 CFR 192.32(a)(1) (see Section 5.4). If phased disposal is the option chosen, the rule limits the disposal unit to a maximum of 40 acres, with no more than two units open at any given time. If continuous di sposal is chosen, no more than 10 acres may be open at any given time. Finally, the agency is proposing to eliminate the distincti on made in the 1989 rule between impoundments constructed pre-1989 and pos t-1989, since all of the remaining pre-1989 impoundments comply with the proposed GACT. The elimination of this distinction also eliminates the requirement that pre-1989 disposal units be monitored annually to demonstrate that the average Rn-222 flux does not exceed 20 pCi/(m 2 -sec).

The conventional milling GACT applies to three ex isting mills and one proposed mill that is in the process of being licensed. The four convent ional mills are the White Mesa mill and the proposed Piñon Ridge mill owned by Energy Fu els; the Shootaring Canyon mill owned by Uranium One, Inc.; and the Sweetwater mill ow ned by Kennecott Uranium Co. . Of the three companies that own conventional mills, one, Energy Fuels, is classified as a small business, on the basis that they have fewer than 500 em ployees (EF 2012 states that Energy Fuels has 255 active employees in the U.S.).

Energy Fuels’ White Mesa mill uses a phased disposal system that complies with the proposed GACT. When its existing open unit is full, it wi ll be contoured and covered. Then, a new unit, constructed in accordance with the proposed GAC T, will be opened to accept future tailings.119 Energy Fuels is proposing a phased disposal system to manage its tailings; this system also complies with the proposed GACT.

Section 5.4 describes the proposed GACTs. Because both the White Mesa mill and the proposed Piñon Ridge mill are in compliance with the pr oposed GACT, it can be concluded that the rulemaking will not impose any new economic impacts on small business (i.e., Energy Fuels). For White Mesa, the proposed rule will actually result in a co st saving as Energy Fuels will no longer have to perform annual monitoring to determine the average radon flux from its impoundments.

The GACT for evaporation ponds at uranium recovery facilities requires that the evaporation ponds be constructed in accordance with design requirements in 40 CFR 192.32(a)(1) and that a minimum depth of 1 meter of liquid be mainta ined in the ponds during operation and standby. The key design requirements for the ponds are for a double liner with a le ak detection system

between the two liners.

In addition to the four conventional mills identified above, the GACT for evaporation ponds applies to ISL facilities and heap leach facilitie s. Currently, there are six operating ISLs (as shown in Table 8) and no operating heap leach f acilities. The operating ISLs are Crow Butte and Smith Ranch owned by Cameco; Alta Mesa ow ned by Mestena Uranium, LLC; Willow Creek owned by Uranium One, Inc.; and Hobson and La Palangana owned by Uranium Energy Corp. Again, using the criterion of fewer than 500 employees, Mestena Uranium, LLC, and Uranium Energy Corp. are small businesses, while both Ca meco and Uranium One, Inc., which is owned by Rosatom, are large businesses.

All of the evaporation ponds at the four conve ntional mills and the six ISLs were built in conformance with 40 CFR 192.32(a)(1). Therefore, the only economic imp act is the cost of complying with the new requirement to maintain a minimum of 1 meter of water in the ponds during operation and standby.

In addition to the operating ISLs listed above, Tabl e 9 shows that there are nine ISLs have been proposed for licensing. These are: Dewey Bu rdock owned by Powert ech Uranium Corp.; Nichols Ranch owned by Uranerz Energy Corp.; ‘Jab and Antelope’ and Moore Ranch owned by Uranium One Americas, Inc., a subsidiary of Rosatom; Church Rock and Crownpoint owned by Hydro Resources, Inc. a subsidiary of Uraniu m Resources, Inc.; Ross owned by Strata Energy Inc., a subsidiary of Australian-based Penins ula Energy Limited; Goliad owned by Uranium Energy Corp.; and Lost Creek owned by Lost Creek ISR, LLC a subsidiary of Ur-Energy. All of these companies, except Rosatom, are small businesses.

According to the licensing documents submitted by th e owners of the proposed ISLs, all will be constructed in conformance with 40 CFR 192.32(a)(1 ). Therefore, the only economic impact is the cost of complying with the new requirement to maintain a minimum of 1 meter of water in the ponds during operation and while in standby status.

The requirement to maintain a min imum of 1 meter of liquid in the ponds is estimated to cost up to $0.03 per pound of U 3 O 8 produced. Considering that the curre nt (i.e., January 30, 2012) price120 of U 3 O 8 is $52 per pound (UxC 2012), this cost does not pose a significant imp act to any of these

small entities.

The GACT for heap leach facili ties applies the phased dis posal option of the GACT for

conventional mills to these facilities and adds the requirement that the heap leach pile be maintained at a minimum 30-percent moisture content by weight du ring operations. Although no heap leach facilities are currently licensed, the small business Energy Fuels is expected to submit a licensing application for the Sh eep Mountain Project. From the preliminary documentation that has been presented (Titan 2011), the Energy Fuels facility will have an evaporation pond, a collection pond, and a raffinate pond. All three ponds will be double lined with leak detection. Based on the unit and facility cost comparisons presented in Table 53 and Table 54

, respectively, the implementation of the proposed GAC Ts at a heap leach facility (such as Sheep Mountain) would increase the U 3 O 8 production cost by about 5%. Ba sed on this small increase, the Sheep Mountain Project would: 1) remain competitive with U 3 O 8 production cost for other types of facilities, and 2) conti nue to provide Energy Fuels with a profit. Energy Fuels is the only entity known to be preparing to submit a licen se application for a heap leach facility.

Of the 20 uranium recovery facilities identifi ed above, 13 are owned by small businesses. As documented above in this report, those 13 faciliti es are either already in compliance with the proposed GACTs, with no additional impact, or compliance with the GACTs would not pose a significant impact to any of th e small businesses (e.g., $52.03 lb -1 versus $52 lb -1 ). Thus, after considering the economic impacts of this proposed rule on small entitie s, it is concluded that this action will not have a significant economic impact on a substantial number of small entities.

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BEIR (Biological Effects of Ionizi ng Radiation) 1988. BEIR IV Report , Health Risks of Radon and Other Internally Deposited Alpha-Emitters: BEIR IV. Committee on Biological Effects of Radiation, Board on Radiation Effects Resear ch, Commission on Life Sciences, National Research Council, National Academy Press.

Black & Veatch 2010. “2009/2010 50 Largest Citie s Water/Wastewater Rate Survey.”

BLS (Bureau of Labor Statistics) 2011. “CPI De tailed Report (tables 1-29 only) August 2011,” Department of Labor, http://www.bls.gov/cpi/tables.htm , accessed 9/16/2011.

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