Document ID: EPA-HQ-OAR-2008-0218-0001
Agency: epa
Document Type: Proposed Rule
Title: National Emission Standards: Radon Emissions from Operating Mill Tailings
Posted Date: 2014-05-02T04:00Z

[Federal Register Volume 79, Number 85 (Friday, May 2, 2014)]
[Proposed Rules]
[Pages 25387-25412]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2014-09728]

[[Page 25387]]

Vol. 79

Friday,

No. 85

May 2, 2014

Part III

Environmental Protection Agency

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40 CFR Part 61

Revisions to National Emission Standards for Radon Emissions from 
Operating Mill Tailings; Proposed Rule

  Federal Register / Vol. 79, No. 85 / Friday, May 2, 2014 / Proposed 
Rules  

[[Page 25388]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 61

[EPA-HQ-OAR-2008-0218; FRL-9816-2]
RIN 2060-AP26

Revisions to National Emission Standards for Radon Emissions From 
Operating Mill Tailings

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
revise certain portions of the National Emission Standards for 
Hazardous Air Pollutants (NESHAP) for radon emissions from operating 
uranium mill tailings. The proposed revisions are based on EPA's 
determination as to what constitutes generally available control 
technology or management practices (GACT) for this area source 
category. We are also proposing to add new definitions to this rule, 
revise existing definitions and clarify that the rule applies to 
uranium recovery facilities that extract uranium through the in-situ 
leach method and the heap leach method.

DATES: Comments must be received on or before July 31, 2014.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
OAR-2008-0218, by one of the following methods:
     www.regulations.gov: Follow the on-line instructions for 
submitting comments.
     Email: a-and-r-docket@epa.gov.
     Fax: 202-566-9744.
     Mail: Air and Radiation Docket, Environmental Protection 
Agency, Mailcode: 2822T, 1200 Pennsylvania Ave. NW., Washington, DC 
20460.
     Hand Delivery: EPA West Building, Room 3334, 1301 
Constitution Ave. NW., Washington, DC 20004. Such deliveries are only 
accepted during the Docket's normal hours of operation, and special 
arrangements should be made for deliveries of boxed information.
    Instructions: Direct your comments to Docket ID No. EPA-HQ-OAR-
2008-0218. EPA's policy is that all comments received will be included 
in the public docket without change and may be made available online at 
www.regulations.gov, including any personal information provided, 
unless the comment includes information claimed to be Confidential 
Business Information (CBI) or other information whose disclosure is 
restricted by statute. Do not submit information that you consider to 
be CBI or otherwise protected through www.regulations.gov or email. The 
www.regulations.gov Web site is an ``anonymous access'' system, which 
means EPA will not know your identity or contact information unless you 
provide it in the body of your comment. If you send an email comment 
directly to EPA without going through www.regulations.gov your email 
address will be automatically captured and included as part of the 
comment that is placed in the public docket and made available on the 
Internet. If you submit an electronic comment, EPA recommends that you 
include your name and other contact information in the body of your 
comment and with any disk or CD-ROM you submit. If EPA cannot read your 
comment due to technical difficulties and cannot contact you for 
clarification, EPA may not be able to consider your comment. Electronic 
files should avoid the use of special characters, any form of 
encryption, and be free of any defects or viruses. For additional 
information about EPA's public docket visit the EPA Docket Center 
homepage at http://www.epa.gov/epahome/dockets.htm.
    Docket: All documents in the docket are listed in the 
www.regulations.gov index. Although listed in the index, some 
information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, will be publicly available only in hard copy. 
Publicly available docket materials are available either electronically 
in www.regulations.gov or in hard copy at the Office of Air and 
Radiation Docket, EPA/DC, EPA West, Room 3334, 1301 Constitution Ave. 
NW., Washington, DC. The Public Reading Room is open from 8:30 a.m. to 
4:30 p.m., Monday through Friday, excluding legal holidays. The 
telephone number for the Public Reading Room is (202) 566-1744, and the 
telephone number for the Air and Radiation Docket is (202) 566-1792.

FOR FURTHER INFORMATION CONTACT: Reid J. Rosnick, Office of Radiation 
and Indoor Air, Radiation Protection Division, Mailcode 6608J, U.S. 
Environmental Protection Agency, 1200 Pennsylvania Ave. NW., 
Washington, DC 20460; telephone number: 202-343-9290; fax number: 202-
343-2304; email address: rosnick.reid@epa.gov.

SUPPLEMENTARY INFORMATION: 
    Outline. The information in this preamble is organized as follows:

I. General Information
    A. Does this action apply to me?
    B. What should I consider as I prepare my comments to EPA?
    C. Acronyms and Abbreviations
    D. Where can I get a copy of this document?
    E. When would a public hearing occur?
II. Background Information for Proposed Area Source Standards
    A. What is the statutory authority for the proposed standards?
    B. What criteria did EPA use in developing the proposed GACT 
standards for these area sources?
    C. What source category is affected by the proposed standards?
    D. What are the production operations, emission sources, and 
available controls?
    E. What are the existing requirements under Subpart W?
    F. How did we gather information for this proposed rule?
    G. How does this action relate to other EPA standards?
    H. Why did we conduct an updated risk assessment?
III. Summary of the Proposed Requirements
    A. What are the affected sources?
    B. What are the proposed requirements?
    C. What are the monitoring requirements?
    D. What are the notification, recordkeeping and reporting 
requirements?
    E. When must I comply with these proposed standards?
IV. Rationale for this Proposed Rule
    A. How did we determine GACT?
    B. Proposed GACT standards for operating mill tailings
V. Other Issues Generated by Our Review of Subpart W
    A. Clarification of the Term ``Standby''
    B. Amending the Definition of ``Operation'' for Conventional 
Impoundments
    C. Weather Events
    D. Applicability of 40 CFR 192.32(a) to Subpart W
VI. Summary of Environmental, Cost and Economic Impacts
    A. What are the air impacts?
    B. What are the cost and economic impacts?
    C. What are the non-air environmental impacts?
VII. Statutory and Executive Order Review
    A. Executive Order 12866: Regulatory Planning and Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health and Safety Risks
    H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution or Use
    I. National Technology Transfer Advancement Act
    J. Executive Order 12898: Federal Actions to Address 
Environmental Justice in Minority Populations and Low-Income 
Populations

[[Page 25389]]

I. General Information

A. Does this action apply to me?

    The regulated categories and entities potentially affected by the 
proposed standards include:

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                                      NAICS
              Category                 code      Examples of regulated
                                       \1\             entities
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Industry:
    Uranium Ores Mining and/or        212291  Area source facilities
     Beneficiating.                            that extract or
                                               concentrate uranium from
                                               any ore processed
                                               primarily for its source
                                               material content.
    Leaching of Uranium, Radium or    212291  Area source facilities
     Vanadium Ores.                            that extract or
                                               concentrate uranium from
                                               any ore processed
                                               primarily for its source
                                               material content.
------------------------------------------------------------------------
\1\ North American Industry Classification System.

    This table is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities likely to be affected by this 
proposed action. If you have any questions regarding the applicability 
of this action to a particular entity, consult either the air permit 
authority for the entity or your EPA regional representative as listed 
in 40 CFR 61.04 of subpart A (General Provisions).

B. What should I consider as I prepare my comments for EPA?

    1. Submitting CBI. Do not submit this information to EPA through 
www.regulations.gov or email. Clearly mark the part or all of the 
information that you claim to be CBI. For CBI information in a disk or 
CD ROM that you mail to EPA, mark the outside of the disk or CD ROM as 
CBI and then identify electronically within the disk or CD ROM the 
specific information that is claimed as CBI. In addition to one 
complete version of the comment that includes information claimed as 
CBI, a copy of the comment that does not contain the information 
claimed as CBI must be submitted for inclusion in the public docket. 
Information marked as CBI will not be disclosed except in accordance 
with procedures set forth in 40 CFR part 2.
    2. Tips for Preparing Your Comments. When submitting comments, 
remember to:
     Identify the rulemaking by docket number and other 
identifying information (subject heading, Federal Register date and 
page number).
     Follow directions--The agency may ask you to respond to 
specific questions or organize comments by referencing a Code of 
Federal Regulations (CFR) part or section number.
     Explain why you agree or disagree, suggest alternatives, 
and substitute language for your requested changes.
     Describe any assumptions and provide any technical 
information and/or data that you used.
     If you estimate potential costs or burdens, explain how 
you arrived at your estimate in sufficient detail to allow for it to be 
reproduced.
     Provide specific examples to illustrate your concerns, and 
suggest alternatives.
     Explain your views as clearly as possible, avoiding the 
use of profanity or personal threats.

Make sure to submit your comments by the comment period deadline 
identified.

C. Acronyms and Abbreviations

    We use many acronyms and abbreviations in this document. These 
include:

AEA--Atomic Energy Act
ALARA--As low as reasonably achievable
BID--Background information document
CAA--Clean Air Act
CAAA--Clean Air Act Amendments of 1990
CCAT--Colorado Citizens Against Toxic Waste
CFR--Code of Federal Regulations
Ci--Curie, a unit of radioactivity equal to the amount of a 
radioactive isotope that decays at the rate of 3.7 x 10\10\ 
disintegrations per second.
DOE--U.S. Department of Energy
EIA--economic impact analysis
EO--Executive Order
EPA--U.S. Environmental Protection Agency
FR--Federal Register
GACT--Generally Available Control Technology
gpm--Gallons Per Minute
HAP--Hazardous Air Pollutant
ICRP--International Commission on Radiological Protection
ISL--In-situ leach uranium recovery, also known as in-situ recovery 
(ISR)
LCF--Latent Cancer Fatality--Death resulting from cancer that became 
active after a latent period following exposure to radiation
NAAQS--National Ambient Air Quality Standards
NCRP--National Council on Radiation Protection and Measurements
mrem--millirem, 1 x 10-\3\ rem
MACT--Maximum Achievable Control Technology
NESHAP--National Emission Standard for Hazardous Air Pollutants
NRC--U.S. Nuclear Regulatory Commission
OMB--Office of Management and Budget
pCi--picocurie, 1 x 10-\12\ curie
Ra-226--Radium-226
Rn-222--Radon-222
Radon flux--A term applied to the amount of radon crossing a unit 
area per unit time, as in picocuries per square centimeter per 
second (pCi/m\2\/sec).
RCRA--Resource Conservation and Recovery Act
Subpart W--National Emission Standards for Radon Emissions from 
Operating Mill Tailings at 40 CFR 61.250-61.256
TEDE--Total Effective Dose Equivalent
UMTRCA--Uranium Mill Tailings Radiation Control Act of 1978
U.S.C.--United States Code

D. Where can I get a copy of this document?

    In addition to being available in the docket, an electronic copy of 
this proposed action will also be available on the Worldwide Web (WWW) 
through the Technology Transfer Network (TTN). Following signature, a 
copy of this proposed action will be posted on the TTN's policy and 
guidance page for newly proposed or promulgated rules at the following 
address: http://www.epa.gov/ttn/oarpg/. The TTN provides information 
and technology exchange in various areas of air pollution control.

E. When would a public hearing occur?

    If anyone contacts EPA requesting to speak at a public hearing 
concerning this proposed rule by July 1, 2014, we will hold a public 
hearing. If you are interested in attending the public hearing, contact 
Mr. Anthony Nesky at (202) 343-9597 to verify that a hearing will be 
held and if you wish to speak. If a public hearing is held, we will 
announce the date, time and venue on our Web site at http://www.epa.gov/radiation.

[[Page 25390]]

II. Background Information for Proposed Area Source Standards

A. What is the statutory authority for the proposed standards?

    Section 112(q)(1) of the Clean Air Act (CAA) requires that National 
Emission Standards for Hazardous Air Pollutants (NESHAP) ``in effect 
before the date of enactment of the Clean Air Act Amendments of 1990 
[Nov. 15, 1990] . . . shall be reviewed and, if appropriate, revised, 
to comply with the requirements of subsection (d) of . . . section 
[112].'' EPA promulgated 40 CFR part 61, Subpart W, ``National Emission 
Standards for Radon Emissions From Operating Mill Tailings,'' 
(``Subpart W'') on December 15, 1989.\1\ EPA is conducting this review 
of Subpart W under CAA section 112(q)(1) to determine what revisions, 
if any, are appropriate.
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    \1\ On April 26, 2007, Colorado Citizens Against Toxic Waste and 
Rocky Mountain Clean Air Action filed a lawsuit against EPA (EPA-HQ-
OAR-2008-0218-0013) for EPA's alleged failure to review and, if 
appropriate, revise NESHAP Subpart W under CAA section 112(q)(1). A 
settlement agreement was entered into between the parties in 
November 2009(EPA-HQ-OAR-2008-0218-0019).
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    Section 112(d) of the CAA requires EPA to establish emission 
standards for major and area source categories that are listed for 
regulation under CAA section 112(c). A major source is any stationary 
source that emits or has the potential to emit 10 tons per year (tpy) 
or more of any single hazardous air pollutant (HAP) or 25 tpy or more 
of any combination of HAP. An area source is a stationary source of HAP 
that is not a major source. For the purposes of Subpart W, the HAP at 
issue is radon-222 (hereafter referred to as ``radon''). We presently 
have no data or information that shows any other HAPs being emitted 
from these impoundments. Calculations of radon emissions from operating 
uranium recovery facilities have shown that facilities regulated under 
Subpart W are area sources (EPA-HQ-OAR-2008-0218-0001, 0002).
    Section 112(q)(1) does not dictate how EPA must conduct its review 
of those NESHAPs issued prior to 1990. Rather, it provides that the 
Agency must review, and if appropriate, revise the standards to comply 
with the requirements of section 112(d). Determining what revisions, if 
any, are appropriate for these NESHAPs is best assessed through a case-
by-case consideration of each NESHAP. As explained below, in this case, 
we have reviewed Subpart W and are revising the standards consistent 
with section 112(d)(5), which provides EPA authority to issue standards 
for area sources.
    Under CAA section 112(d)(5), the Administrator may elect to 
promulgate standards or requirements for area sources ``which provide 
for the use of generally available control technologies or management 
practices by such sources to reduce emissions of hazardous air 
pollutants.'' Under section 112(d)(5), the Administrator has the 
discretion to use generally available control technology or management 
practices (GACT) in lieu of maximum achievable control technology 
(MACT) under section 112(d)(2) and (d)(3), which is required for major 
sources. Pursuant to section 112(d)(5), we are proposing revisions to 
Subpart W to reflect GACT.

B. What criteria did EPA use in developing the proposed GACT standards 
for these area sources?

    Additional information on generally available control technologies 
or management practices (GACT) is found in the Senate report on the 
legislation (Senate Report Number 101-228, December 20, 1989), which 
describes GACT as:

* * * methods, practices and techniques which are commercially 
available and appropriate for application by the sources in the 
category considering economic impacts and the technical capabilities 
of the firms to operate and maintain the emissions control systems.

Consistent with the legislative history, we can consider costs and 
economic impacts in determining GACT, which is particularly important 
when developing regulations for source categories, like this one, that 
may include small businesses.
    Determining what constitutes GACT involves considering the control 
technologies and management practices that are generally available to 
the area sources in the source category. We also consider the standards 
applicable to major sources \2\ in the same industrial sector to 
determine if the control technologies and management practices are 
transferable and generally available to area sources. In appropriate 
circumstances, we may also consider technologies and practices at area 
and major sources in similar categories to determine whether such 
technologies and practices could be considered generally available for 
the area source category at issue. Finally, as noted above, in 
determining GACT for a particular area source category, we consider the 
costs and economic impacts of available control technologies and 
management practices on that category.
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    \2\ None of the sources in this source category are major 
sources.
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C. What source category is affected by the proposed standards?

    As defined by EPA pursuant to the CAA, the source category for 
Subpart W is ``facilities licensed [by the U.S. Nuclear Regulatory 
Commission (NRC)] to manage uranium byproduct material during and 
following the processing of uranium ores, commonly referred to as 
uranium mills and their associated tailings.'' 40 CFR 61.250. Subpart W 
defines ``uranium byproduct material or tailings'' as ``the waste 
produced by the extraction or concentration of uranium from any ore 
processed primarily for its source material content.'' \3\ 40 CFR 
61.251(g). For clarity, in this proposed rule we refer to this source 
category by the term ``uranium recovery facilities'' and we are 
proposing to add this phrase to the definitions section of the rule. 
Use of this term encompasses the existing universe of facilities whose 
HAP emissions are currently regulated under Subpart W. Uranium recovery 
facilities process uranium ore to extract uranium. The HAP emissions 
from any type of uranium recovery facility that manages uranium 
byproduct material or tailings is subject to regulation under Subpart 
W. This currently includes three types of uranium recovery facilities: 
(1) Conventional uranium mills; (2) in-situ leach recovery facilities; 
and (3) heap leach facilities. Subpart W requirements specifically 
apply to the affected sources at the uranium recovery facilities that 
are used to manage or contain the uranium byproduct material or 
tailings. Common names for these structures may include, but are not 
limited to, impoundments, tailings impoundments, evaporation or holding 
ponds, and heap leach piles. However, the name itself is not important 
for determining whether Subpart W requirements apply to that structure; 
rather, applicability is based

[[Page 25391]]

on the use of these structures to manage or contain uranium byproduct 
material.
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    \3\ Pursuant to the Atomic Energy Act of 1954, as amended, the 
Nuclear Regulatory Commission defines ``source material'' as ``(1) 
Uranium or thorium or any combination of uranium or thorium in any 
chemical or physical form; or (2) Ores that contain, by weight, one-
twentieth of one percent (0.05 percent), or more, of uranium or 
thorium, or any combination of uranium or thorium.'' (10 CFR 
20.1003) For a uranium recovery facility licensed by the Nuclear 
Regulatory Commission under 10 CFR Part 40, ``byproduct material'' 
means the ``tailings or wastes produced by the extraction or 
concentration of uranium or thorium from ore processed primarily for 
its source material content, including discrete surface wastes 
resulting from uranium solution extraction processes.'' (10 CFR 
20.1003 and 40.4)
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D. What are the production operations, emission sources, and available 
controls?

    As noted above, uranium recovery and processing currently occurs by 
one of three methods: (1) Conventional milling; (2) in-situ leach 
(ISL); and (3) heap leach. Below we present a brief explanation of the 
various uranium recovery methods and the usual structures that contain 
uranium byproduct materials.
(1) Conventional Mills
    Conventional milling is one of the two primary recovery methods 
that are currently used to extract uranium from uranium-bearing ore. 
Conventional mills are typically located in areas of low population 
density. Only one conventional mill in the United States is currently 
operating; all others are in standby, in decommissioning (closure) or 
have been decommissioned.
    A conventional uranium mill is a chemical plant that extracts 
uranium using the following process:
    (A) Trucks deliver uranium ore to the mill, where it is crushed 
before the uranium is extracted through a leaching process. In most 
cases, sulfuric acid is the leaching agent, but alkaline solutions can 
also be used to leach the uranium from the ore. The process generally 
extracts 90 to 95 percent of the uranium from the ore.
    (B) The mill then concentrates the extracted uranium to produce a 
uranium oxide material which is called ``yellowcake'' because of its 
yellowish color.\4\
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    \4\ The term ``yellowcake'' is still commonly used to refer to 
this material, although in addition to yellow the uranium oxide 
material can also be black or grey in color.
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    (C) Finally, the yellowcake is 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.
    (D) The extraction process in (A) and (B) above produces both solid 
and liquid wastes (i.e., uranium byproduct material, or ``tailings'') 
which are transported from the extraction location to an on-site 
tailings impoundment or a pond for temporary storage.
    Uranium byproduct material/tailings are typically created in slurry 
form during the crushing, leaching and concentration processes and are 
then deposited in an impoundment or ``mill tailings pile'' which must 
be carefully monitored and controlled. This is because the mill 
tailings contain heavy metal ore constituents, including radium. The 
radium decays to produce radon, which may then be released to the 
environment. Because radon is a radioactive gas which may be inhaled 
into the respiratory tract, EPA has determined that exposure to radon 
and its daughter products contributes to an increased risk of lung 
cancer.\5\
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    \5\ http://www.epa.gov/radon/risk_assessment.html.
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    The holding or evaporation ponds at this type of facility hold 
liquids containing byproduct material from which HAP emissions are also 
regulated under Subpart W. These ponds are discussed in more detail in 
the next section.
(2) In-Situ Leach/Recovery
    In-situ leach or recovery sites (ISL/ISR, in this document we will 
use ISL) represent the majority of the uranium recovery operations that 
currently exist. The research and development projects and associated 
pilot projects of the 1980s demonstrated ISL as a viable uranium 
recovery technique where site conditions (e.g., geology) are amenable 
to its use. Economically, this technology produces a better return on 
the investment dollar (EPA-HQ-OAR-2008-0218-0087); therefore, the cost 
to produce uranium is more favorable to investors. Due to this, the 
trend in uranium production has been toward the ISL process.
    In-situ leaching is defined as the underground leaching or recovery 
of uranium from the host rock (typically sandstone) by chemicals, 
followed by recovery of uranium at the surface. Leaching, or more 
correctly the re-mobilization of uranium into solution, is accomplished 
through the underground injection of a lixiviant (described below) into 
the host rock (i.e., ore body) through wells that are connected to the 
ore formation. A lixiviant is a chemical solution used to extract (or 
leach) uranium from underground ore bodies.
    The injection of a lixiviant essentially reverses the geochemical 
reactions that resulted in the formation of the uranium deposit. The 
lixiviant assures that the dissolved uranium, as well as other metals, 
remains in the solution while it is collected from the ore zone by 
recovery wells, which pump the solution to the surface. At the surface, 
the uranium is recovered in an ion-exchange column and further 
processed into yellowcake. The yellowcake is packaged and 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.
    Two types of lixiviant solutions can be used, loosely defined as 
``acid'' or ``alkaline'' systems. In the U.S., the geology and 
geochemistry of the majority of the uranium ore bodies favors the use 
of alkaline lixiviants such as bicarbonate-carbonate lixiviant and 
oxygen. Other factors in the choice of the lixiviant are the uranium 
recovery efficiencies, operating costs, and the ability to achieve 
satisfactory ground-water restoration.
    After processing, lixiviant is recharged (more carbonate/
bicarbonate or dissolved carbon dioxide is added to the solution) and 
pumped back down into the formation for reuse in extracting more 
uranium. However, a small amount of this liquid is held back from 
reinjection to maintain a proper hydraulic gradient \6\ within the 
wellfield. The amount of liquid held back is a function of the 
characteristics of the formation properties (e.g., permeability, 
hydraulic conductivity, transmissivity). This excess liquid is sent to 
an impoundment (often called an evaporation pond or holding pond) on 
site or injected into a deep well for disposal. These impoundments, 
since they contain uranium byproduct material, are subject to the 
requirements of Subpart W.\7\ With respect to the lixiviant reinjected 
into the wellfield, there is a possibility of the lixiviant spreading 
beyond the zone of the uranium deposit (excursion), and this produces a 
threat of ground-water contamination. The operator of the ISL facility 
remediates any excursion by pumping large amounts of water in or out of 
the formation (at various wells) to contain the excursion, and this 
water (often containing byproduct material either before or after 
injection into or withdrawal from the formation) is often stored in the 
evaporation or holding ponds.\8\ Although the excursion control 
operation itself is not regulated under Subpart W, the ponds that 
contain byproduct material are regulated under that subpart, since they 
are a potential source of radon emissions. After the ore body has been 
depleted, restoration of the formation (attempting to return the 
formation back to its original geochemical and geophysical

[[Page 25392]]

properties) is accomplished by flushing the host rock with water and 
sometimes additional chemicals. Since small amounts of uranium are 
still contained in the returning water, the restoration fluids are also 
considered byproduct material, and are usually sent to evaporation 
ponds for disposition.
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    \6\ The hydraulic gradient determines which direction water in 
the formation will flow, which in this case limits the amount of 
water that migrates away from the ore zone.
    \7\ As described later in this preamble, the design requirements 
for these impoundments are derived from the RCRA requirements for 
impoundments.
    \8\ By controlling the hydraulic gradient of the formation the 
operator controls the direction of flow of water, containing the 
water within specified limits of the formation.
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(3) Heap Leaching
    In addition to conventional uranium milling and ISL, some 
facilities may use an extraction method known as heap leaching. In some 
instances uranium ore is of such low grade, or the geology of the ore 
body is such that it is not cost-effective to remove the uranium via 
conventional milling or through ISL.\9\ In this case a heap leaching 
method may be utilized.
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    \9\ The ore grade is so low that it is not practical to invest 
large sums of capital to extract the uranium. Heap leach is a much 
more passive and relatively inexpensive system.
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    No such facilities currently operate to recover uranium in the U.S. 
However, there are plans for at least one facility to open in the U.S. 
within the next few years.
    Heap leach operations involve the following process:

    A. Small pieces of ore are placed in a large pile, or ``heap,'' 
on an impervious geosynthetic liner with perforated pipes under the 
heap. For the purposes of Subpart W the impervious pad will meet the 
requirements for design and construction of impoundments found at 40 
CFR 192.32(a).
    B. An acidic solution is then sprayed \10\ over the ore to 
dissolve the uranium it contains.
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    \10\ Other technology includes drip systems, sometimes used at 
gold extraction heaps, and flooding of the heap leach pile.
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    C. The uranium-rich solution drains into the perforated pipes, 
where it is collected and transferred to an ion-exchange system.
    D. The heap is ``rested,'' meaning that there is a temporary 
cessation of application of acidic solution to allow for oxidation 
of the ore before leaching begins again.
    E. The ion-exchange system extracts the uranium from solution 
where it is later processed into a yellowcake.\11\
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    \11\ It is our understanding that either ion-exchange or solvent 
extraction techniques can be used to recover uranium at heap leach 
facilities. The decision to use one type or the other depends 
largely on the quality of the ore at a particular site.
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    F. Once the uranium has been extracted, the remaining solution 
still contains small amounts of uranium byproduct material (the 
extraction process is not 100% effective), and this solution is 
either piped to the heap leach pile to be reused or piped to an 
evaporation or holding pond. In the evaporation pond it is subject 
to the Subpart W requirements.
    G. The yellowcake is 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.
    H. Finally, there is a final drain down of the heap solutions, 
as well as a possible rinsing of the heap. These solutions will 
contain byproduct material and will be piped to evaporation or 
holding ponds, where they become subject to the Subpart W 
requirements. The heap leach pile will be closed in place according 
to the requirements of 40 CFR 192.32.

    Today we are proposing to regulate the HAP emissions from heap 
leach uranium extraction under Subpart W, in addition to conventional 
impoundments and evaporation ponds, which are already regulated under 
this Subpart. Our rationale (explained in greater detail in Section 
IV.D.4.) is that from the moment uranium extraction takes place in the 
heap, uranium byproduct material is left behind. Therefore the 
byproduct material must be managed with the same design as a 
conventional impoundment, with a liner and leak detection system 
prescribed at 40 CFR 192.32(a), and an effective method of limiting 
radon emissions while the heap leach pile is being used to extract 
uranium.
    As described above, there may also be holding or evaporation ponds 
at this type of facility. In many cases these ponds hold liquids 
containing byproduct material. The byproduct material is contained in 
the liquids used to leach uranium from the ore in the heap leach pile 
as well as draining the heap leach pile in preparation for closure. The 
HAP emissions from these fluids are currently regulated under Subpart 
W.

E. What are the existing requirements under Subpart W?

    Subpart W was promulgated on December 15, 1989 (54 FR 51654). At 
the time of promulgation the predominant form of uranium recovery was 
through the use of conventional mills. There are two separate standards 
required in Subpart W. The first standard is for ``existing'' 
impoundments, e.g., those in existence and licensed by the NRC (or it's 
Agreement States) on or prior to December 15, 1989. Owners or operators 
of existing tailings impoundments must ensure that emissions from those 
impoundments do not exceed a radon (Rn-222) flux standard of 20 
picocuries per meter squared per second (pCi/m\2\/sec). As stated at 
the time of promulgation: ``This rule will have the practical effect of 
requiring the mill owners to keep their piles wet or covered.''\12\ 
Keeping the piles (impoundments) wet or covered with soil would reduce 
radon emissions to a level that would meet the standard. This is still 
considered an effective method to reduce radon emissions at all uranium 
tailings impoundments.
---------------------------------------------------------------------------

    \12\ See 54 FR 51689.
---------------------------------------------------------------------------

    The method for monitoring for compliance with the radon flux 
standard was prescribed as Method 115, found at 40 CFR part 61, 
Appendix B. The owners or operators of existing impoundments must 
report to EPA the results of the compliance testing for any calendar 
year by no later than March 31 of the following year.
    There is currently one existing operating mill with impoundments 
that pre-date December 15, 1989, and two mills that are currently in 
standby mode.
    The second standard applies to ``new'' impoundments designed and/or 
constructed after December 15, 1989. The requirements applicable to new 
impoundments are work practice standards that regulate either the size 
and number of impoundments, or the amount of tailings that may remain 
uncovered at any time. 40 CFR 61.252(b) states that no new tailings 
impoundment can be built after December 15, 1989, unless it is 
designed, constructed and operated to meet one of the following two 
work practices:

    1. Phased disposal in lined impoundments that are no more than 
40 acres in area, and meet the requirements of 40 CFR 192.32(a) as 
determined by the NRC. The owner or operator shall have no more than 
two impoundments, including existing impoundments, in operation at 
any one time.
    2. Continuous disposal of tailings that are dewatered and 
immediately disposed with no more than 10 acres uncovered at any 
time, and operated in accordance with 40 CFR 192.32(a) as determined 
by the NRC.

    The basis of the work practice standards is to (1) limit the size 
of the impoundment, which limits the radon source; or (2) utilize the 
continuous disposal system, which prohibits large accumulations of 
uncovered tailings, limiting the amount of radon released.
    The work practice standards described above were promulgated after 
EPA considered a number of factors that influence the emissions of Rn-
222 from tailings impoundments, including the climate and the size of 
the impoundment. For example, for a given concentration of Ra-226 in 
the tailings, and a given grain size of the tailings, the moisture 
content of the tailings will control the radon emission rate; the 
higher the moisture content the lower the emission rate. In the arid 
and semi-arid areas of the country where most impoundments are located 
or proposed, the annual evaporation rate is quite high. As a result, 
the exposed tailings

[[Page 25393]]

(absent controls like sprinkling) dry rapidly. In previous assessments, 
we explicitly took the fact of rapid drying into account by using a Rn-
222 flux rate of 1 pCi/m\2\/s per pCi/g Ra-226 to estimate the Rn-222 
source term from the dry areas of the impoundments. (Note: The 
estimated source terms from the ponded (areas completely covered by 
liquid) and saturated areas of the impoundments are considered to be 
zero, reflecting the complete attenuation of the Rn-222).
    Another factor we considered was the area of the impoundment, which 
has a direct linear relationship with the Rn-222 source term, more so 
than the depth or volume of the impoundment. Again, assuming the same 
Ra-226 concentration and grain sizes in the tailings, a 100-acre dry 
impoundment will emit 10 times the radon of a 10-acre dry impoundment. 
This linear relationship between size and Rn-222 source term is one of 
the main reasons that Subpart W imposed size restrictions on all future 
impoundments (40 acres per impoundment if phased disposal is chosen and 
10 acres total uncovered if continuous disposal is chosen).
    Subpart W also mandates that all tailings impoundments at uranium 
recovery facilities comply with the requirements at 40 CFR 192.32(a). 
EPA explained the reason for adding this requirement in the preamble as 
follows:

    ``EPA recognizes that in the case of a tailings pile which is 
not synthetically or clay lined (the clay lining can be the result 
of natural conditions at the site) water placed on the tailings in 
an amount necessary to reduce radon levels, can result in ground 
water contamination. In addition, in certain situations the water 
can run off and contaminate surface water. EPA cannot allow a 
situation where the reduction of radon emissions comes at the 
expense of increased pollution of the ground or surface water. 
Therefore, all piles will be required to meet the requirements of 40 
CFR 192.32(a) which protects water supplies from contamination. 
Under the current rules, existing piles are exempt from these 
provisions, this rule will end that exemption.''

54 FR 51654, 51680 (December 15, 1989). Therefore, all impoundments are 
required to meet the requirements at 40 CFR 192.32(a).
    Section 192.32(a) includes a cross-reference to the surface 
impoundment design and construction requirements of hazardous waste 
surface impoundments regulated under the Resource Conservation and 
Recovery Act (RCRA), found at 40 CFR 264.221. Those requirements state 
that the impoundment shall be designed, constructed and installed to 
prevent any migration of wastes out of the impoundment to the adjacent 
subsurface soil or ground water or surface water at any time during the 
active life of the impoundment. Briefly, 40 CFR 264.221(c) requires 
that the liner system must include:

    1. A top liner designed and constructed of materials (e.g., a 
geomembrane) to prevent the migration of hazardous constituents into 
the liner during the active life of the unit.
    2. A composite bottom liner consisting of at least two 
components. The upper component must be designed and constructed of 
materials (e.g., a geomembrane) to prevent the migration of 
hazardous constituents into this component during the active life of 
the unit. The lower component must be designed and constructed of 
materials to minimize the migration of hazardous constituents if a 
breach in the upper component were to occur. The lower component 
must be constructed of at least three feet of compacted soil 
material with a hydraulic conductivity of no more than 1 x 10\-7\ 
cm/sec.
    3. A leachate collection and removal system between the liners, 
which acts as a leak detection system. This system must be capable 
of detecting, collecting and removing hazardous constituents at the 
earliest practicable time through all areas of the top liner likely 
to be exposed to the waste or liquids in the impoundment.

There are other requirements for the design and operation of the 
impoundment, and these include construction specifications, slope 
requirements, sump and liquid removal requirements.\13\
---------------------------------------------------------------------------

    \13\ For detailed information on the design and operating 
requirements, refer to 40 CFR Part 264 Subpart K--Surface 
Impoundments.
---------------------------------------------------------------------------

F. How did we gather information for this proposed rule?

    This section describes the information we used as the basis for 
making the determination to revise Subpart W. We collected this 
information using various methods. We performed literature searches, 
where appropriate, of the engineering methods used by existing uranium 
recovery facilities in the United States as well as the rest of the 
world. We used this information to determine whether the technology 
used to contain uranium byproduct material had advanced since the time 
of the original promulgation of Subpart W. We reviewed and compiled a 
list of existing and proposed uranium recovery facilities and the 
containment technologies being used, as well as those proposed to be 
used. We compared and contrasted those technologies with the 
engineering requirements of hazardous waste surface impoundments 
regulated under Subtitle C of the Resource Conservation and Recovery 
Act (RCRA), which are used as the design basis for existing uranium 
byproduct material impoundments.
    We collected information on existing uranium mills and in-situ 
leach facilities by issuing information collection requests authorized 
under section 114(a) of the CAA to seven uranium recovery facilities. 
At the time, this represented 100% of existing facilities. Since then, 
Cotter Corp. has closed its Canon City facility. These requests 
required uranium recovery companies to provide detailed information 
about the uranium mill and/or in-situ leaching facility, as well as the 
number, sizes and types of affected sources (tailings impoundments, 
evaporation ponds and collection ponds) that now or in the past held 
uranium byproduct material. We requested information on the history of 
operation since 1975, ownership changes, whether the operation was in 
standby mode and whether plans existed for new facilities or 
reactivated operations were expected.\14\ We also reviewed the 
regulatory history of Subpart W and the radon measurement methods used 
to determine compliance with the existing standards. Below is a 
synopsis of the information we collected and our analyses.
---------------------------------------------------------------------------

    \14\ Section 114(a) letters and responses can be found at http://www.epa.gov/radiation/neshaps/subpartw/rulemaking-activity.html.
---------------------------------------------------------------------------

1. Pre-1989 Conventional Mill Impoundments
    We have been able to identify three facilities, either operating or 
on standby,\15\ that have been in operation since before the 
promulgation of Subpart W in 1989. These existing facilities must 
ensure that emissions from their operational, pre-1989 impoundments\16\ 
not exceed a radon (Rn-222) flux standard of 20 pCi/m\2\/sec. The 
method for monitoring for compliance with the radon flux standard was 
prescribed as Method 115, found at 40 CFR part 61, Appendix B. These 
facilities must also meet the requirements in 40 CFR 61.252(c), which 
cross-references the requirements of 40 CFR 192.32(a)
---------------------------------------------------------------------------

    \15\ ``Standby'' is when a facility impoundment is licensed for 
the continued placement of tailings/byproduct material but is 
currently not receiving tailings/byproduct material. See Section 
V.A. for a discussion of this definition that we are proposing to 
add to Subpart W.
    \16\ In this preamble when we use the generic term 
``impoundment,'' we are using the term as described by industry.
---------------------------------------------------------------------------

    The White Mesa Conventional Mill in Blanding, Utah, has one pre-
1989 impoundment (known by the company as Cell 3) that is currently in 
operation and near capacity but is still authorized and continues to 
receive tailings. The

[[Page 25394]]

company is now pumping any residual free solution out of the cell and 
contouring the sands. It will then be determined whether any more 
solids need to be added to the cell to fill it to the specified final 
elevation. It is expected to close in the near future (EPA-HQ-OAR-2008-
0218-0069). The mill also uses an impoundment constructed before 1989 
as an evaporation pond (known as Cell 1). To the extent this 
evaporation pond contains byproduct material, its HAP emissions are 
also regulated by Subpart W.
    The Sweetwater conventional mill is located 42 miles northwest of 
Rawlins, Wyoming. The mill operated for a short time in the 1980s and 
is currently in standby status. Annual radon values collected by the 
facility indicate that there is little measurable radon flux from the 
mill tailings that are currently in the lined impoundment. This 
monitoring program remains active at the facility. According to company 
records, of the 37 acres of tailings, approximately 28.3 acres of 
tailings are covered with soil; the remainder of the tailings are 
continuously covered with water. The dry tailings have an earthen cover 
that is maintained as needed. During each monitoring event one hundred 
radon flux measurements are taken on the tailings continuously covered 
by soil, as required by Method 115 for compliance with Subpart W. The 
mean radon flux for the exposed tailings over the past 21 years was 3.5 
pCi/m \2\/sec. The radon flux for the entire tailings impoundment was 
calculated to be 6.01 pCi/m \2\/sec. The calculated radon flux from the 
entire tailings impoundment surface is thus approximately 30% of the 
20.0 pCi/m \2\/sec standard (EPA-HQ-OAR-2008-0218-0087).
    The Shootaring Canyon project is a conventional mill located about 
3 miles north of Ticaboo, Utah, in Garfield County. The approximately 
1,900-acre site includes an ore pad, a small milling building, and a 
tailings impoundment system that is partially constructed. The mill 
operated for a very short period of time. Shootaring Canyon did pre-
date the standard, but the mill was shut down prior to the promulgation 
of the standard. The impoundment is in a standby status and has an 
active license administered by the Utah Department of Environmental 
Quality, Division of Radiation Control. The future plans for this 
uranium recovery operation are unknown. Current activities at this 
remote site consist of intermittent environmental monitoring by 
consultants to the parent company (EPA-HQ-OAR-2008-0218-0087).
    The Shootaring Canyon mill operated for approximately 30 days. 
Tailings were deposited in a portion of the upper impoundment. A lower 
impoundment was conceptually designed but has not been built. Milling 
operations in 1982 produced 25,000 cubic yards of tailings, deposited 
in a 2,508 m \2\ (0.62 acres) area. The tailings are dry except for 
moisture associated with occasional precipitation events; consequently, 
there are no beaches.\17\ The tailings have a soil cover that is 
maintained by the operating company. Radon sampling for the 2010 year 
took place in April. Again, one hundred radon flux measurements were 
collected. The average radon flux from this sampling event was 11.9 
pCi/m \2\-sec.
---------------------------------------------------------------------------

    \17\ The term ``beaches'' refers to portions of the tailings 
impoundment where the tailings are wet but not saturated or covered 
with liquids.
---------------------------------------------------------------------------

    A fourth mill is Cotter Corporation in Canon City, Colorado. The 
mill no longer exists, and the pre-1989 impoundments are in closure.
2. 1989-Present Conventional Mill Impoundments
    There currently is only one operating conventional mill with an 
impoundment that was constructed after December 15, 1989. The White 
Mesa conventional mill in Utah has two impoundments (Cell 4A and Cell 
4B: Cell 4A is currently operating as a conventional impoundment and 
Cell 4B is being used as an evaporation pond) designed and constructed 
after 1989. The facility uses the phased disposal work practice.
    There are several conventional mills in the planning and/or 
permitting stage and conventional impoundments at these mills will be 
required to utilize one of the current work practice standards.
3. In-Situ Leach Facilities
    After 1989 the price of uranium began to fall, and the uranium 
mining and milling industry essentially collapsed, with very few 
operations remaining in business. However, several years ago the price 
of uranium began to rise so that it became profitable once more for 
companies to consider uranium recovery. ISL has become the preferred 
choice for uranium extraction where suitable geologic conditions exist.
    Currently there are five ISL facilities in operation: (1) The Alta 
Mesa project in Brooks County, Texas; (2) the Crow Butte Operation in 
Dawes County, Nebraska; (3) the Hobson/La Palangana Operation in South 
Texas; (4) the Willow Creek (formerly Christensen Ranch/Irigaray Ranch) 
Operation in Wyoming; and (5) the Smith Ranch-Highland Operation in 
Converse County, Wyoming.\18\ These facilities use or have used 
evaporation ponds to hold back liquids containing uranium byproduct 
material from reinjection to maintain a proper hydraulic gradient 
within the wellfield.\19\ These ponds are subject to the Subpart W 
requirements and range in size from less than an acre to up to 40 
acres. Based on the information provided to us the ponds meet the 
requirements of 40 CFR 61.252(c).
---------------------------------------------------------------------------

    \18\ Source: U.S. Energy Information Administration, http://www.eia.gov/uranium/production/quarterly/html/qupd_tbl4.html.
    \19\ The Alta Mesa operation uses deep well injection rather 
than evaporation ponds.
---------------------------------------------------------------------------

    There are approximately 11 additional ISL facilities in various 
stages of licensing or on standby. It is anticipated that there could 
be approximately another 20-30 license applications over the next 5-10 
years.\20\
---------------------------------------------------------------------------

    \20\ Source: http://www.nrc.gov/materials/uranium-recovery/license-apps/ur-projects-list-public.pdf.
---------------------------------------------------------------------------

4. Heap Leach Facilities
    As stated earlier, there are currently no operating heap leach 
facilities in the United States. We are aware of two or three potential 
future operations. The project most advanced in the application process 
is the Sheep Mountain facility in Wyoming. Energy Fuels has announced 
its intent to submit a license application to the NRC in March 2014. 
One or two other as yet to be determined operations may be located in 
Lander County, Nevada and/or a site in New Mexico.\21\
---------------------------------------------------------------------------

    \21\ http://www.nrc.gov/materials/uranium-recovery/license-apps/ur-projects-list-public.pdf.
---------------------------------------------------------------------------

5. Flux Requirement Versus Management Practices for Conventional 
Impoundments in Operation Before December 15, 1989
    In performing our analysis we considered the information we 
received from all the existing conventional impoundments. We also 
looked at the compliance history of the existing conventional 
impoundments. After this review we considered two specific questions: 
(1) Are any of the conventional impoundments using any novel methods to 
reduce radon emissions? (2) Is there now any reason to believe that any 
of the existing conventional impoundments could not comply with the 
management practices for new conventional impoundments, in which case 
would we need to continue to make the distinction between conventional 
impoundments constructed before or after December 15, 1989? We arrived 
at the following

[[Page 25395]]

conclusions: First, we are not aware of any conventional impoundment 
that uses any new or different technologies to reduce radon emissions. 
Conventional impoundment operators continue to use the standard method 
of reducing radon emissions by limiting the size of the impoundment and 
covering tailings with soil or keeping tailings wet. These are very 
effective methods for limiting the amount of radon released to the 
environment.
    Second, we believe that only one existing operating conventional 
impoundment designed and in operation before December 15, 1989, could 
not meet the work practice standards. This impoundment is Cell 3 at the 
White Mesa mill, which is expected to close in 2014 (Personal 
communication between EPA staff and Utah Department of Environmental 
Quality staff, May 16, 2013, EPA-HQ-2008-0218-0081). We were very clear 
in our 1989 rulemaking that all conventional mill impoundments must 
meet the requirements of 40 CFR 192.32(a), which, in addition to 
requiring ground-water monitoring, also required the use of liner 
systems to ensure there would be no leakage from the impoundment into 
the ground water. We did this by removing the exemption for existing 
piles from the 40 CFR 192.32(a) requirements (54 FR 51680). However, we 
did not require those existing impoundments to meet either the phased 
disposal or continuous disposal work practice standards, which limit 
the exposed area and/or number of conventional impoundments, thereby 
limiting the potential for radon emissions. This is because at the time 
of promulgation of the rule, conventional impoundments existed that 
were larger in area than the maximum work practice standard of 40 acres 
used for the phased disposal work practice, or 10 acres for the 
continuous disposal requirement. This area limitation was important in 
reducing the amount of exposed tailings that were available to emit 
radon. However, we recognized that by instituting a radon flux standard 
we would require owners and operators to limit radon emissions from 
these preexisting impoundments (usually by placing water or soil on 
exposed portions of the impoundments). The presumption was that 
conventional impoundments constructed before this date could otherwise 
be left in a dry and uncovered state, which would allow for unfettered 
release of radon. The flux standard was promulgated to have the 
practical effect of requiring owners and operators of these old 
impoundments to keep their tailings either wet or covered with soil, 
thereby reducing the amount of radon that could be emitted (54 FR 
51680).
    We believe that the existing conventional impoundments at both the 
Shootaring Canyon and Sweetwater facilities can meet the work practice 
standards in the current Subpart W regulation. The conventional 
impoundments at both these facilities are less than 40 acres in area 
and are synthetically lined as per the requirements in 40 CFR 
192.32(a). We also have information that the new conventional 
impoundments operating at the White Mesa mill will utilize the phased 
work practice standard of limiting conventional impoundments to no more 
than two, each 40 acres or less in area. We also have information that 
Cell 3 at the White Mesa facility will be closed in 2014, and the 
phased disposal work method will be used for the remaining cells. 
(Personal communication between EPA staff and staff of Utah Department 
of Environmental Quality, May 16, 2013 (EPA-HQ-2008-0218-0081). As a 
result, we find there would be no conventional impoundment designed or 
constructed before December 15, 1989 that could not meet a work 
practice standard. Since the conventional impoundments in existence 
prior to December 15, 1989 appear to meet the work practice standards, 
we are proposing to eliminate the distinction of whether the 
conventional impoundment was constructed before or after December 15, 
1989. We are also proposing that all conventional impoundments 
(including those in existence prior to December 15, 1989) must meet the 
requirements of one of the two work practice standards, and that the 
flux standard of 20 pCi/m\2\/sec will no longer be required for the 
impoundments in existence prior to December 15, 1989.

G. How does this action relate to other EPA standards?

    Under the CAA, EPA promulgated Subpart W, which includes standards 
and other requirements for controlling radon emissions from operating 
mill tailings at uranium recovery facilities. Under our authority in 
the Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA), we 
have also issued standards that are more broadly applicable to uranium 
and thorium byproduct materials at active and inactive uranium recovery 
facilities. NRC (or Agreement States \22\) and DOE implement and 
enforce these standards at these uranium recovery facilities as 
directed by UMTRCA. These standards, located in 40 CFR part 192, 
address the radiological and non-radiological hazards of uranium and 
thorium byproduct materials in ground water and soil, in addition to 
air. For the non-radiological hazards, UMTRCA directed us to promulgate 
standards consistent with those used by EPA to regulate non-
radiological hazardous materials under RCRA. Therefore, our part 192 
standards incorporate the ground-water protection requirements applied 
to hazardous waste management units under RCRA and specify the 
placement of uranium or thorium byproduct materials in impoundments 
constructed in accordance with RCRA requirements. Radon emissions from 
non-operational impoundments (i.e., those with final covers) are 
limited in 40 CFR part 192 to the emissions levels of 20 pCi/m\2\/sec. 
We are currently preparing a regulatory proposal to update provisions 
of 40 CFR part 192, with emphasis on ground-water protection for ISL 
facilities. As explained in previous sections, Subpart W currently 
contains reference to some of the part 192 standards.
---------------------------------------------------------------------------

    \22\ An Agreement State is a State that has entered into an 
agreement with the Nuclear Regulatory Commission under section 274 
of the Atomic Energy Act of 1954 (42 U.S.C. 2021)and has authority 
to regulate byproduct materials (as defined in section 11e.(2)of the 
Atomic Energy Act)and the disposal of low-level radioactive waste 
under such agreement.
---------------------------------------------------------------------------

H. Why did we conduct an updated risk assessment?

    While not required by or conducted as part of our GACT analysis, 
one of the tasks we performed for our own purposes was to update the 
risk analysis we performed when we promulgated Subpart W in 1989. We 
performed a comparison between the 1989 risk assessment and current 
risk assessment approaches, focusing on the adequacy and the 
appropriateness of the original assessments. We did this for 
informational purposes only and not for or as part of our GACT 
analysis. Instead, we prepared this updated risk assessment because we 
wanted to demonstrate that even using updated risk analysis procedures 
(i.e. using procedures updated from those used in the 1980s), the 
existing radon flux standard appears to be protective of the public 
health and the environment. We did this by using the information we 
collected to perform new risk assessments for existing facilities, as 
well as two idealized ``generic'' sites, one located in the eastern 
half of the United States and one located in the southwest United 
States. (These two model sites do not exist. They are idealized using 
representative features

[[Page 25396]]

of mills in differing climate and geography). This information has been 
collected into one document \23\ that has been placed in the docket 
(EPA-HQ-OAR-2008-0218-0087) for this proposed rulemaking.
---------------------------------------------------------------------------

    \23\ 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).
---------------------------------------------------------------------------

    As part of this work, we evaluated various computer models that 
could be used to calculate the doses and risks due to the operation of 
conventional and ISL uranium recovery facilities, and selected CAP88 V 
3.0 for use in this analysis. CAP88 V 3.0 was developed in 1988 from 
the AIRDOS, RADRISK, and DARTAB computer programs, which had been 
developed for the EPA at the Oak Ridge National Laboratory (ORNL).
    CAP88 V 3.0, which stands for ``Clean Air Act Assessment Package-
1988 version 3.0,'' is used to demonstrate compliance with the NESHAP 
requirements applicable to radionuclides. CAP88 V 3.0 calculates the 
doses and risk to a designated receptor as well as to the surrounding 
population. Exposure pathways evaluated by CAP88 V 3.0 are: inhalation, 
air immersion, ingestion of vegetables, meat, and milk, and ground 
surface exposure. CAP88 V 3.0 uses a modified Gaussian plume equation 
to estimate the average dispersion of radionuclides released from up to 
six emitting sources. The sources may be either elevated stacks, such 
as a smokestack, or uniform area sources, such as the surface of a 
uranium byproduct material impoundment. Plume rise can be calculated 
assuming either a momentum or buoyant-driven plume.
    At several sites analyzed in this evaluation only site-wide 
releases of radon were available to us. This assessment was limited by 
the level of detail provided by owners and operators of uranium 
recovery facilities. In instances where more specific site data were 
available, site-wide radon releases were used as a bounding estimate. 
Assessments are done for a circular grid of distances and directions 
for a radius of up to 80 kilometers (50 miles) around the facility. The 
Gaussian plume model produces results that agree with experimental data 
as well as any comparable model, is fairly easy to work with, and is 
consistent with the random nature of turbulence. A description of CAP88 
V 3.0 and the computer models upon which it is based is provided in the 
CAP88 V 3.0 Users Manual.\24\
---------------------------------------------------------------------------

    \24\ http://www.epa.gov/radiation/assessment/CAP88 V 3.0/
index.html.
---------------------------------------------------------------------------

    The uranium recovery facilities that we analyzed included three 
existing conventional mills (Cotter, White Mesa and Sweetwater), five 
operating ISL operations (the Alta Mesa project in Brooks County, 
Texas; the Crow Butte Operation in Dawes County, Nebraska; the Hobson/
La Palangana Operation in South Texas; the Willow Creek (formerly 
Christensen Ranch/Irigaray Ranch) Operation in Wyoming; and the Smith 
Ranch-Highland Operation in Converse County, Wyoming), and two generic 
sites assumed for the location of conventional mills (we chose 
conventional mills because we believe they have the potential for 
greater radon emissions). One generic site was modeled in the southwest 
United States (Western Generic) while the other was assumed to be 
located in the eastern United States (Eastern Generic).\25\ An Eastern 
generic site was selected for the second generic site to accommodate 
the recognition that a number of uranium recovery facilities are 
expected to apply for construction licenses in the future, and to 
determine potential risks in geographic areas of the U.S. that 
customarily have not hosted uranium recovery facilities. For this 
assessment the conventional mills we were most interested in were the 
White Mesa mill and the Sweetwater mill. (The Shootaring Canyon mill 
was not analyzed, because the impoundment is very small and is soil 
covered, and the Cotter facility is now in closure). These conventional 
mills are either in operation or standby and are subject to the flux 
standard of 20 pCi/m\2\/sec. The risk analyses performed for these two 
mills showed that the maximum lifetime cancer risks from radon 
emissions from the White Mesa impoundments were 1.1 x 10-4 
while the maximum lifetime cancer risks from radon associated with the 
impoundments at the Sweetwater mill were 2.4 x 10-5. As we 
indicated in our original 1989 risk assessment, in protecting public 
health, EPA strives to provide the maximum feasible protection by 
limiting lifetime cancer risk from radon exposure to approximately 1 in 
10,000 (i.e., 10-4).\26\ The analyses also estimated that 
the total cancer risk to the populations surrounding all ten modeled 
uranium sites (i.e., total cancer fatalities) is between 0.0015 and 
0.0026 fatal cancers per year, or approximately 1 case every 385 to 667 
years for the 4 million persons living within 80 km of the uranium 
recovery facilities. Similarly, the total cancer incidence for all ten 
modeled sites is between 0.0021 and 0.0036 cancers per year, or 
approximately 1 case every 278 to 476 years. The analyses are described 
in more detail in the background document generated for this 
proposal.\27\ As stated above, we performed this risk assessment for 
informational purposes only. The risk assessment was not required or 
considered during our analysis for proposing GACT standards for uranium 
recovery facilities (e.g., conventional impoundments, non-conventional 
impoundments or heap leach piles).
---------------------------------------------------------------------------

    \25\ There is a potential in the future for uranium recovery in 
areas like south-central Virginia.
    \26\ See 54 FR 51656
    \27\ All risks are presented as LCF risks. If it is desired to 
estimate the morbidity risk, simply multiply the LCF risk by 1.39. 
For a more detailed analysis of cancer mortality and morbidity, 
please see the Background Information Document, Docket number EPA-
HQ-OAR-0218-0087.
---------------------------------------------------------------------------

III. Summary of the Proposed Requirements

    We are proposing to revise Subpart W to include requirements we 
have identified that are generally available for controlling radon 
emissions in a cost-effective manner, and are not currently included in 
Subpart W. Specifically, we are proposing to require that non-
conventional impoundments and heap leach piles must maintain minimum 
liquid levels to control their radon emissions from these affected 
sources.
    Additionally, we are revising Subpart W to propose GACT standards 
for the affected sources at conventional uranium mills, ISL facilities 
and heap leach facilities. Given the evolution of uranium recovery 
facilities over the last 20 years, we believe it is appropriate to 
revise Subpart W to tailor the requirements of the rule to the 
different types of facilities in existence at this time. We are 
therefore proposing to revise Subpart W to add appropriate definitions, 
standards and other requirements that are applicable to HAP emissions 
at these uranium recovery facilities.
    Our experience with ensuring that uranium recovery facilities are 
in compliance with Subpart W also leads us to propose three more 
changes. First, we are proposing to remove certain monitoring 
requirements that we believe are no longer necessary for demonstrating 
compliance with the proposed GACT standards. Second, we are proposing 
to revise certain definitions so that owners and operators clearly 
understand when Subpart W applies to their facility. Third, we are 
proposing to clarify what specific liner

[[Page 25397]]

requirements must be met under Subpart W.\28\
---------------------------------------------------------------------------

    \28\ Under its CAA authority, EPA requires facilities subject to 
Subpart W to build impoundments in a manner that complies with the 
requirements found in 40 CFR 192. As a matter of convenience, EPA 
cross-references the part 192 requirements in Subpart W instead of 
copying them directly into Subpart W. This cross-referencing 
convention is often used in rulemakings.
---------------------------------------------------------------------------

    Taken altogether, the proposed revisions to Subpart W are 
appropriate for updating, clarifying and strengthening the management 
of radon emissions from the uranium byproduct material generated at 
uranium recovery facilities.

A. What are the affected sources?

    Today we are proposing to revise Subpart W to include requirements 
for affected sources at three types of operating uranium recovery 
facilities: (1) Conventional uranium mills; (2) ISL facilities; and (3) 
heap leach facilities. The affected sources at these uranium recovery 
facilities include conventional impoundments, non-conventional 
impoundments where tailings are contained in ponds and covered by 
liquids (examples of these affected sources are evaporation or holding 
ponds that may exist at conventional mills, ISL facilities and heap 
leach facilities), and heap leach piles. The proposed GACT standards 
and the rationale for these proposed standards are discussed below and 
in Section IV. We request comment on all aspects of these proposed 
requirements.

B. What are the proposed requirements?

1. Conventional Impoundments
    In the 1989 promulgation of Subpart W we created two work practice 
standards, phased disposal and continuous disposal, for uranium 
tailings impoundments designed and constructed after December 15, 1989. 
The work practice standards, which limit the exposed area and/or number 
of conventional impoundments at a uranium recovery facility, require 
that these impoundments be no larger than 40 acres (for phased 
disposal) or 10 uncovered acres (for continuous disposal). We also 
limited the number of conventional impoundments operating at any one 
time to two. We took this approach because we recognized that the radon 
emissions from very large conventional impoundments could impose 
unacceptable health effects if the piles were left dry and uncovered. 
The 1989 promulgation also included the requirements in 40 CFR 
192.32(a), which include design and construction requirements for the 
impoundments as well as requirements for prevention and mitigation of 
ground-water contamination.
    As discussed earlier, we no longer believe that a distinction needs 
to be made for conventional impoundments based on the date when they 
were designed and/or constructed. We believe that the existing 
conventional impoundments at both the Shootaring Canyon and Sweetwater 
facilities can meet the work practice standards in the current Subpart 
W regulation. The conventional impoundments at both these facilities 
are less than 40 acres in area and are synthetically lined as per the 
requirements in 40 CFR 192.32(a)(1). The existing cell 3 at the White 
Mesa mill will undergo closure in 2014 and will be replaced with the 
impoundments currently under construction that meet the phased disposal 
work practice standard. Therefore, there is no reason not to subject 
these older impoundments to the work practice standards required for 
impoundments designed or constructed after December 15, 1989. By 
incorporating these impoundments under the work practices provision of 
Subpart W, it is no longer necessary to require radon flux monitoring, 
and we are proposing to eliminate that requirement.
    The proposed elimination of the monitoring requirement in 40 CFR 
61.253 applies only to those facilities currently subject to the radon 
flux standard in 40 CFR 61.252(a), which applies to only the three 
conventional impoundments in existence prior to the original 
promulgation of Subpart W on December 15, 1989. While we are proposing 
to eliminate the radon monitoring requirement for these three 
impoundments under Subpart W, this action does not relieve the owner or 
operator of the uranium recovery facility of the monitoring and 
maintenance requirements of their operating license issued by the NRC 
or its Agreement States. These requirements are found at 10 CFR Part 
40, Appendix A, Criterion 8 and 8A. Additionally, NRC, through its 
Regulatory Guide 4.14, may also recommend incorporation of radionuclide 
air monitoring at operating facility boundaries.
    Further, when the impoundments formally close they are subject to 
the radon monitoring requirements of 40 CFR 192.32(a)(3), also under 
the NRC licensing requirements.
    From a cost standpoint, by not requiring radon monitoring we expect 
that for all three sites the total annual average cost savings would be 
$29,200, with a range from about $21,000 to $37,000. More details on 
economic costs can be found in Section IV.B of this preamble.
    For the proposed rule we also evaluated the requirements of 40 CFR 
192.32(a) as they pertain to the Subpart W standards. The requirements 
of 40 CFR 192.32(a) are included in the NRC's regulations and are 
reviewed for compliance by NRC during the licensing process for a 
uranium recovery facility. We determined that the requirements at 40 
CFR 192.32(a)(1), which reference the RCRA requirements for design and 
operation of surface impoundments at 40 CFR 264.221, are the only 
requirements necessary for EPA to incorporate for Subpart W, as they 
are effective methods of containing tailings and protecting ground 
water while also limiting radon emissions. This liner requirement, 
described earlier in this preamble, remains in use for the permitting 
of hazardous waste land disposal units under RCRA. The requirements at 
40 CFR 192.32(a)(1) contain safeguards to allow for the placement of 
tailings and yet provide an early warning system in the event of a leak 
in the liner system. We are therefore proposing to retain the two work 
practice standards and the requirements of 40 CFR 192.32(a)(1) as GACT 
for conventional impoundments because these methods for limiting radon 
emissions while also protecting ground water have proven effective for 
these types of impoundments.
2. Non-Conventional Impoundments Where Tailings Are Contained in Ponds 
and Covered by Liquids
    Today we are proposing a GACT standard specifically for non-
conventional impoundments where uranium byproduct materials are 
contained in ponds and covered by liquids. Common names for these 
structures may include, but are not limited to, impoundments and 
evaporation or holding ponds. These affected sources may be found at 
any of the three types of uranium recovery facilities.
    These units meet the existing applicability criteria in 40 CFR 
61.250 to classify them for regulation under Subpart W. The holding or 
evaporation ponds located at conventional mills, ISL facilities and 
potentially heap leach facilities contain uranium byproduct material, 
either in solid form or dissolved in solution, and therefore their 
emissions are regulated under Subpart W. As defined at 40 CFR 
61.251(g), uranium byproduct material or tailings means the waste 
produced by the extraction or concentration of uranium from any ore 
processed primarily for its source material content.

[[Page 25398]]

Therefore, emissions for the ponds at uranium recovery facilities that 
contain either uranium byproduct material in solid form or 
radionuclides dissolved in liquids are regulated under Subpart W. Today 
we are again stating that determination and proposing a GACT standard 
specifically for these impoundments.
    Evaporation or holding ponds, while sometimes smaller in area than 
conventional impoundments, perform a basic task. They hold uranium 
byproduct material until it can be disposed. Our survey of existing 
ponds shows that they contain liquids, and, as such, this general 
practice has been sufficient to limit the amount of radon emitted from 
the ponds, in many cases, to almost zero. Because of the low potential 
for radon emissions from these impoundments, we do not believe it is 
necessary to monitor them for radon emissions. We have found that as 
long as approximately one meter of liquid is maintained in the pond, 
the effective radon emissions from the pond are so low that it is 
difficult to determine whether there is any contribution above 
background radon values. EPA has stated in the Final Rule for Radon-222 
Emissions from Licensed Uranium Mill Tailings: Background Information 
Document (August, 1986):

    ``Recent technical assessments of radon emission rates from 
tailings indicate that radon emissions from tailings covered with 
less than one meter of water, or merely saturated with water, are 
about 2% of emissions from dry tailings. Tailings covered with more 
than one meter of water are estimated to have a zero emissions rate. 
The Agency believes this calculated difference between 0% and 2% is 
negligible. The Agency used an emission rate of zero for all 
tailings covered with water or saturated with water in estimating 
radon emissions.''

    Therefore, we are proposing as GACT that these impoundments meet 
the design and construction requirements of 40 CFR 192.32(a)(1), with 
no size/area restriction, and that during the active life of the pond 
at least one meter of liquid be maintained in the pond.
    We are also proposing that no monitoring be required for this type 
of impoundment. We have received information and collected data that 
show there is no acceptable radon flux test method for a pond holding a 
large amount of liquid. (Method 115 does not work because a solid 
surface is needed to place the large area activated carbon canisters 
used in the Method). Further, even if there was an acceptable method, 
we recognize that radon emissions from the pond would be expected to be 
very low because the liquid acts as an effective barrier to radon 
emissions; given that radon-222 has a very short half-life (3.8 days), 
there simply is not enough time for most of the radon produced by the 
solids or from solution to migrate to the water surface and cross the 
water/air interface before decaying(EPA-HQ-OAR-2008-0218-0087). It 
therefore appears that monitoring at these ponds is not necessary for 
demonstrating compliance with the proposed standards. We do, however, 
ask for comment and supporting information on three issues: (1) Whether 
these impoundments need to be monitored with regard to their radon 
emissions, and why; (2) whether these impoundments need to be monitored 
to ensure at least one meter of liquid is maintained in the pond at all 
times, and (3) if these impoundments do need monitoring, what methods 
could a facility use (for example, what types of radon collection 
devices, or methods to measure liquid levels) at evaporation or holding 
ponds.
3. Heap Leach Piles
    The final impoundment category for which we are proposing GACT 
standards is heap leach piles. We are proposing to require that heap 
leach piles meet the phased disposal work practice standard set out in 
Section III B. 1. of this preamble (which limits an owner/operator to 
no more than two operating heap leach piles of no more than 40 acres 
each at any time) and the design and construction requirements at 40 
CFR 192.32(a)(1) as GACT. We are also requiring heap leach piles to 
maintain minimum moisture content of 30% so that the byproduct material 
in the heap leach pile does not dry out, which would increase radon 
emissions from the heap leach pile.
    As noted earlier in the preamble, there are currently no operating 
uranium heap leach facilities in the United States. We are aware that 
the one currently proposed heap leach facility will use the design and 
operating requirements at 40 CFR 192.32(a)(1) for the design of its 
heap. Since this requirement will be used at the only example we have 
for a heap leach pile, it (design and operating requirements at 40 CFR 
192.32(a)(1)), along with the phased disposal work practice standard 
(limiting the number and size of heap leach piles), will be the 
standards that we propose as GACT for heap leach piles. The premise is 
that the operator of a heap would not want to lose any of the uranium-
bearing solution; thus, it is cost effective to maintain a good liner 
system so that there will be no leakage and ground water will be 
protected. Also, use of the phased disposal work practice standard will 
limit the amount of exposed uranium byproduct material that would be 
available to emit radon. If we assume that uranium ore (found in the 
heap leach pile) and the resultant leftover byproduct material after 
processing emit radon at the same rate as uranium byproduct material in 
a conventional impoundment (a conservative estimate), we can also 
assume that the radon emissions will be nearly the same as two 40 acre 
conventional impoundments.
    We recognize that owners and operators of conventional impoundments 
also limit the amount of radon emitted by keeping the tailings in the 
impoundments covered, either with soil or liquids. At the same time, 
however, we recognize that keeping the uranium byproduct material in 
the heap in a saturated or near-saturated state (in order to reduce 
radon emissions) is not a practical solution as it would be at a 
conventional tailings impoundment. In the definitions at 40 CFR 
61.251(c) we have defined ``dewatered'' tailings as those where the 
water content of the tailings does not exceed 30% by weight. We are 
proposing today to require operating heaps to maintain moisture content 
of greater than 30% so that the byproduct material in the heap is not 
allowed to become dewatered which would allow more radon emissions. We 
are specifically asking for comment on the amount of liquid that should 
be required in the heap, and whether the 30% figure is a realistic 
objective. We are also asking for comments on precisely where in the 
heap leach pile this requirement must be met. The heap leach pile may 
not be evenly saturated during the uranium extraction process. The 
sprayer/drip system commonly used on the top of heap leach piles 
usually results in a semi-saturated moisture condition at the top of 
the pile, since flow of the lixiviant is not uniformly spread across 
the top of the pile. As downward flow continues, the internal areas of 
the pile become saturated. We are requesting information and comment on 
where specifically in the pile the 30% moisture content should apply.

C. What are the monitoring requirements?

    As the rule currently exists, only mills with existing conventional 
impoundments in operation on or prior to December 15, 1989, are 
currently required to monitor to ensure compliance with the radon flux 
standard. The reason for this is because at the time of promulgation of 
the 1989 rule, EPA stated that no flux monitoring would be required for 
new impoundments because the proposed

[[Page 25399]]

work practice standards would be effective in reducing radon emissions 
from operating impoundments by limiting the amount of tailings exposed 
(54 FR 51681). Since we have now determined that existing older 
conventional impoundments can meet one of the two work practice 
standards, we are proposing to eliminate the radon flux monitoring 
requirement.
    In reviewing Subpart W we looked into whether we should extend 
radon monitoring to all affected sources constructed and operated after 
1989 so that the monitoring requirement would apply to all conventional 
impoundments, non-conventional impoundments and heap leach piles 
containing uranium byproduct materials. We also reviewed how this 
requirement would apply to facilities where Method 115 is not 
applicable, such as at impoundments totally covered by liquids. We 
concluded that the original work practice standards (now proposed as 
GACT) continue to be an effective practice for the limiting of radon 
emissions from conventional impoundments and from heap leach piles. We 
also concluded that by maintaining an effective water cover on non-
conventional impoundments the radon emissions from those impoundments 
are so low as to be difficult to differentiate from background radon 
levels at uranium recovery facilities. Therefore, we are proposing 
today that it is not necessary to require radon monitoring for any 
affected sources regulated under Subpart W. We seek comment on our 
conclusion that radon monitoring is not necessary for any of these 
sources as well as on any available cost-effective options for 
monitoring radon at non-conventional impoundments totally covered by 
liquids.

D. What are the notification, recordkeeping and reporting requirements?

    New and existing affected sources are required to comply with the 
existing requirements of the General Provisions (40 CFR part 61, 
subpart A). The General Provisions include specific requirements for 
notifications, recordkeeping and reporting, including provisions for 
notification of construction and/or modification and startup as 
required by 40 CFR 61.07, 61.08 and 61.09.
    Today we are also proposing that all affected sources will be 
required to maintain certain records pertaining to the design, 
construction and operation of the impoundments, both including 
conventional impoundments, and nonconventional impoundments, and heap 
leach piles. We are proposing that these records be retained at the 
facility and contain information demonstrating that the impoundments 
and/or heap leach pile meet the requirements in section 192.32(a)(1), 
including but not limited to, all tests performed that prove the liner 
is compatible with the material(s) being placed on the liner. For 
nonconventional impoundments we are proposing that this requirement 
would also include records showing compliance with the continuous one 
meter of liquid in the impoundment; \29\ for heap leach piles, we are 
proposing that this requirement would include records showing that the 
30% moisture content of the pile is continuously maintained. Documents 
showing that the impoundments and/or heap leach pile meet the 
requirements in section 192.32(a)(1) are already required as part of 
the pre-construction application submitted under 40 CFR 61.07, so these 
records should already be available. Records showing compliance with 
the one meter liquid cover requirement for nonconventional impoundments 
and records showing compliance with the 30% moisture level required in 
heap leach piles can be created and stored during the daily inspections 
of the tailings and waste retention systems required by the NRC (and 
Agreement States) under the inspection requirements of 10 CFR 40, 
Appendix A, Criterion 8A.
---------------------------------------------------------------------------

    \29\ The one meter liquid requirement pertains to having one 
meter of liquid cover any and all solid byproduct material. We do 
not anticipate a large quantity of solid byproduct material in these 
nonconventional impoundments (EPA-HQ-OAR-2008-0218-0088).
---------------------------------------------------------------------------

    Because we are proposing new record-keeping requirements for 
uranium recovery facilities, we are required by the Paperwork Reduction 
Act (PRA) to prepare an estimate of the burden of such record-keeping 
on the regulated entity, in both cost and hours necessary to comply 
with the requirements. We have submitted the Information Collection 
Request (ICR) containing this burden estimate and other supporting 
documentation to the Office of Management and Budget (OMB). See Section 
VII.B for more discussion of the PRA and ICR.
    We believe the record-keeping requirements proposed today will not 
create a significant burden for operators of uranium recovery 
facilities. As described earlier, we are proposing to require retention 
of three types of records: (1) Records demonstrating that the 
impoundments and/or heap leach pile meet the requirements in section 
192.32(a)(1) (e.g. the design and liner testing information); (2) 
records showing that one meter of water is maintained to cover the 
byproduct material stored in nonconventional impoundments; and (3) 
records showing that heap leach piles maintain a moisture content of at 
least 30%.
    Documents demonstrating that the affected sources comply with 
section 192.32(a)(1) requirements are necessary for the facility to 
obtain regulatory approval from NRC (or an NRC Agreement State) and EPA 
to construct and operate the affected sources (this includes any 
revisions during the period of operations). Therefore, these records 
will exist independent of Subpart W requirements and will not need to 
be continually updated as a result of this record-keeping requirement 
in Subpart W; however, we are proposing to include this record-keeping 
requirement in Subpart W to require that the records be maintained at 
the facility during its operational lifetime (in some cases the records 
might be stored at a location away from the facility, such as corporate 
offices). This might necessitate creating copies of the original 
records and providing a location for storing them at the facility.
    Keeping a record to provide confirmation that water to a depth of 
one meter is maintained above the byproduct material stored in 
nonconventional impoundments should also be relatively straightforward. 
This would involve placement of a measuring device or devices in or at 
the edge of the impoundment to allow observation of the water level 
relative to the level of byproduct material in the impoundment. Such 
devices need not be highly technical and might consist of, for example, 
measuring sticks with easily-observable markings placed at various 
locations, or marking the sides of the impoundment to illustrate 
different water depths. As noted earlier, NRC and Agreement State 
licenses require operators to inspect the facility on a daily basis. 
Limited effort should be necessary to make observations of water depth 
and record the information in inspection log books that are already 
kept on site and available to inspectors.
    Similarly, daily inspections would provide a mechanism for 
recording moisture content of heap leach piles. However, because no 
heap leach facilities are currently operating, there is more 
uncertainty about exactly how the operator will determine that the heap 
has maintained a 30% moisture content. As discussed in more detail in 
Section IV.E.4 of this preamble, soil moisture probes are readily 
available and could be used for this purpose. Such probes could be 
either left in the heap leach pile, placed at locations that provide a

[[Page 25400]]

representative estimate for the heap as a whole, or facility personnel 
could use handheld probes to collect readings. The facility might also 
employ mass-balance estimates to provide a further check on the data 
collected.
    We estimate the burden in hours and cost for uranium recovery 
facilities to comply with the proposed recordkeeping requirements are 
as follows:

 Table 1--Burden Hours and Costs for Proposed Recordkeeping Requirements
                   [Annual figures except where noted]
------------------------------------------------------------------------
                   Activity                        Hours        Costs
------------------------------------------------------------------------
Maintaining Records for the section                     *20     * $1,360
 192.32(a)(1) requirements....................
Verifying the one meter liquid requirement for          288       12,958
 nonconventional impoundments.................
Verifying the 30% moisture content at heap            2,068       86,548
 leach piles using multiple soil probes.......
------------------------------------------------------------------------
* These figures represent a one-time cost to the facility.

    Burden levels for heap leach piles are most uncertain because they 
depend on the chosen method of measurement (e.g., purchasing and 
maintaining multiple probes or a smaller number of handheld units) as 
well as the personnel training involved (e.g., a person using a 
handheld unit will likely need more training than someone who is simply 
recording readings from already-placed probes). We request comment on 
our estimates of burden, as well as suggestions of methods that could 
readily and efficiently be used to collect the required information. 
More discussion of the ICR and opportunities for comment may be found 
in Section VII.B.

E. When must I comply with these proposed standards?

    All existing affected sources subject to this proposed rule would 
be required to comply with the rule requirements upon the date of 
publication of the final rule in the Federal Register. To our 
knowledge, there is no existing operating uranium recovery facility 
that would be required to modify its affected sources to meet the 
requirements of the final rule; however, we request any information 
regarding affected sources that would not meet these requirements. New 
sources would be required to comply with these rule requirements upon 
the date of publication of the final rule in the Federal Register or 
upon startup of the facility, whichever is later.

IV. Rationale for This Proposed Rule

A. How did we determine GACT?

    As provided in CAA section 112(d)(5), we are proposing standards 
representing GACT for this area source category. In developing the 
proposed GACT standards, we evaluated the control technologies and 
management practices that are available to reduce HAP emissions from 
the affected sources and identified those that are generally available 
and utilized by operating uranium recovery facilities.
    As noted in Section II.F., for this proposal we solicited 
information on the available controls and management practices for this 
area source category using written facility surveys (surveys authorized 
by section 114(a) of the CAA), reviews of published literature, and 
reviews of existing facilities (EPA-HQ-OAR-0218-0066). We also held 
discussions with trade association and industry representatives and 
other stakeholders at various public meetings.\30\ Our determination of 
GACT is based on this information. We also considered costs and 
economic impacts in determining GACT (See Section VI.).
---------------------------------------------------------------------------

    \30\ See http://www.epa.gov/radiation/neshaps/subpartw/rulemaking-activity.html for a list of presentations made at public 
meetings held by EPA and at various conferences open to the public.
---------------------------------------------------------------------------

    We identified two general management practices that reduce radon 
emissions from affected sources. These general management practices are 
currently being used at all existing uranium recovery facilities. 
First, limiting the area of exposed tailings in conventional 
impoundments limits the amount of radon that can be emitted. The work 
practice standards currently included in Subpart W require owners and 
operators of affected sources to implement this management practice by 
either limiting the number and area of existing, operating impoundments 
or covering dewatered tailings to allow for no more than 10 acres of 
exposed tailings. This is an existing requirement of Subpart W and of 
the NRC licensing requirements; hence, owners and operators of uranium 
recovery facilities are already incurring the costs associated with 
limiting the area of conventional impoundments (and as proposed, heap 
leach piles) to 40 acres or less (as well as no more than two 
conventional impoundments in operation at any one time), or limiting 
the area of exposed tailings to no more than 10 acres.
    Second, covering uranium byproduct materials with liquids is a 
general management practice that is an effective method for limiting 
radon emissions. This general management practice is often used at 
nonconventional impoundments, which, as stated earlier, are also known 
as evaporation or holding ponds. These nonconventional impoundments 
also contain byproduct material, and thus their HAP emissions are 
regulated under Subpart W. They are also regulated under the NRC 
operating license. While they hold mostly liquids, they are still 
designed and constructed in the manner of conventional impoundments, 
meaning they meet the requirements of section 192.32(a)(1). While this 
management practice of covering uranium byproduct materials in 
impoundments with liquids is not currently required under Subpart W, 
facilities using this practice have generally shown its effectiveness 
in reducing emissions in both conventional impoundments (that make use 
of phased disposal) and nonconventional impoundments (i.e. holding or 
evaporation ponds). We are therefore proposing to require the use of 
liquids in nonconventional impoundments as a way to limit radon 
emissions.
    Therefore, after review of the available information and from the 
evidence we have examined, we have determined that a combination of the 
management practices listed above will be effective in limiting radon 
emissions from this source category, and will do so in a cost effective 
manner. We also believe that since heap leach piles are in many ways 
similar to the design of conventional impoundments, the same 
combination of work practices (limitation to no more than two operating 
heap leach piles, each one no more than 40 acres) will limit radon 
emissions in heap leach piles. We discuss our reasons supporting these 
conclusions in more detail in Section IV.B.

[[Page 25401]]

B. Proposed GACT Standards for Operating Mill Tailings

1. Requirements at 40 CFR 192.32(a)(1)
    As an initial matter, we determined that the requirements at 40 CFR 
192.32(a)(1), which reference the RCRA requirements for the design and 
construction of liners at 40 CFR 264.221, continue to be an effective 
method of containment of tailings for all types of affected sources 
(EPA-HQ-OAR-2008-0218-0015). The liner requirements, described earlier 
in this document, remain in use for the permitting of hazardous waste 
land disposal units under RCRA. Because of the requirement for nearly 
impermeable boundaries between the tailings and the subsurface, and the 
requirement for leak detection between the liners, we have determined 
that the requirements contain enough safeguards to allow for the 
placement of tailings and also provide an early warning system in the 
event of a leak in the liner system (EPA-HQ-OAR-2008-0218-0015). For 
this reason we are proposing to require as GACT that conventional 
impoundments, non-conventional impoundments and heap leach piles all 
comply with the liner requirements in 40 CFR 192.32(a)(1). Previously, 
Subpart W contained this requirement but included a more general 
reference to 40 CFR 192.32(a); we are proposing to replace that general 
reference with a more specific reference to 40 CFR 192.32(a)(1) to 
narrow the requirements under this proposed rule to only the design and 
construction requirements for the liner of the impoundment contained in 
40 CFR 192.32(a)(1).
    The estimated average cost of the liner requirement for each type 
of impoundment at uranium recovery facilities is listed in the table 
below (EPA-HQ-OAR-2008-0218-0087):

                                         Table 2--Estimated Liner Costs
----------------------------------------------------------------------------------------------------------------
                      Table 2--Proposed GACT standards costs per pound of U[ihel3]O[ihel8]
-----------------------------------------------------------------------------------------------------------------
                                                                         Unit cost ($/lb U[ihel3]O[ihel8])
                                                                 -----------------------------------------------
                                                                   Conventional         ISL         Heap Leach
----------------------------------------------------------------------------------------------------------------
GACT--Double Liners for Nonconventional Impoundments............          $1.04           $3.07          $0.22
GACT--Maintaining 1 Meter of Water in Nonconventional                      0.013           0.010          0.0010
 Impoundments...................................................
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
----------------------------------------------------------------------------------------------------------------

    Table 2 presents a summary of the unit cost (per pound of 
U3O8) for implementing each GACT at each of the 
three types of uranium recovery facilities. In addition to presenting 
the GACT costs individually, Table 2 presents the total unit cost to 
implement all relevant GACTs at each type of facility.
    Based on the Table 2, implementing all four GACTs would result in 
unit cost (per pound of U3O8) increases of about 
2%, 6%, and 5% at conventional mills, ISL, and heap leach type uranium 
recovery facilities, respectively.
    In making these cost estimates, we have assumed the following: (1) 
A conventional impoundment is no larger than 40 acres in size, which is 
the maximum size allowed for the phased disposal option; (2) a 
nonconventional impoundment is no larger than 80 acres in size (the 
largest size we have seen); and (3) a heap leach pile is no larger than 
40 acres in size (again, the maximum size allowed under the phased 
disposal work practice standard, although as with conventional 
impoundments the owner or operator is limited to two of these affected 
sources to be in operation at any time).
    We do not have precise data for the costs associated with the liner 
requirements at conventional impoundments using the continuous disposal 
work practice standard because currently none exist, but a reasonable 
maximum approximation would be the costs for the 80 acre 
nonconventional impoundment, since it is the largest we have seen. We 
believe that no additional costs would be incurred for building a 
conventional impoundment that will use the continuous disposal option 
above what we estimated for building a nonconventional impoundment but 
we ask for comment on whether this assumption is reasonable. We also 
ask for data on the costs of building a conventional impoundment using 
continuous disposal, and how those costs would differ from the 
estimates provided above, or whether the costs we have listed for 
building a conventional impoundment using phased disposal are a 
reasonable approximation of the costs for building a conventional 
impoundment using continuous disposal.
    These liner systems are already required by 40 CFR 192.32(a)(1), 
which, as explained above, are requirements promulgated by EPA under 
UMTRCA that are incorporated into NRC regulations and implemented and 
enforced by NRC and NRC Agreement States through their licensing 
requirements. Therefore, we are not placing any additional liner 
requirements on facilities or requiring them to incur any additional 
costs to build their conventional or nonconventional impoundments or 
heap leach piles above and beyond what an owner or operator of these 
impoundments must already incur to obtain an NRC or NRC Agreement State 
license.
    The liner systems we are proposing that heap leach piles must use 
are the same as those used for conventional and nonconventional 
impoundments. We estimate that the average costs associated with the 
construction of a 40 acre liner that complies with 40 CFR 
192.32(a)(1)is approximately $15.3 million. When compared to the 
baseline capital costs associated with the facility (estimated at $356 
million)(EPA-HQ-OAR-2008-0218-0087), the costs for constructing this 
type of liner system per facility is about 4% of the total baseline 
capital costs of a heap leach pile facility (EPA-HQ-OAR-2008-0218-
0087).\31\
---------------------------------------------------------------------------

    \31\ For our purposes, baseline conditions are defined as a 
reference point that reflects the world without the proposed 
regulation. It is the starting point for conducting an economic 
analysis of the potential benefits and costs of a proposed 
regulation. The defined baseline influences first the level of 
emissions expected without regulatory intervention. It thereby also 
influences the projected level of emissions reduction that may be 
achieved as a consequence of the proposed regulation. Baselines have 
no standard definition besides the fact that they simply provide a 
reference scenario against which changes in economic and 
environmental conditions (in this case radon emissions) can be 
measured. In some instances, baselines have been established based 
on the assumption that economic, environmental and/or other 
conditions will continue on the present path or trend, purely as 
time dependant extensions of presently observed patterns. In other 
instances, baselines are derived from elaborate modeling 
projections. Because in all cases their purpose is to project a view 
of the world without the proposed regulatory intervention, baselines 
are sometimes termed ``do nothing'' or ``business as usual'' 
scenarios.

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[[Page 25402]]

2. Conventional Impoundments
    In the 1989 promulgation of Subpart W we required new conventional 
impoundments to comply with one of two work practice standards, phased 
disposal or continuous disposal. These work practice standards contain 
specific limits on the exposed area and/or number of operating 
conventional impoundments to limit radon emissions because we 
recognized that radon emissions from very large impoundments could 
impose unacceptable health effects if the piles were left dry and 
uncovered. We are proposing as the GACT standard that all conventional 
impoundments--both existing impoundments and new impoundments--comply 
with one of the two work practice standards, phased disposal or 
continuous disposal, because these methods for limiting radon emissions 
by limiting the area of exposed tailings continue to be effective 
methods for reducing radon emissions from these impoundments (reference 
EPA 520-1-86-009, August 1986). We are proposing that existing 
impoundments also comply with one of the two work practice standards 
because, as discussed earlier, we no longer believe that a distinction 
needs to be made for conventional impoundments based on the date when 
they were designed and/or constructed.
    We are also not aware of any conventional impoundments either in 
existence or planned that use any other technologies or management 
practices to reduce radon emissions. Operators continue to use the 
general management practices discussed above for reducing radon 
emissions from their conventional impoundments, i.e., limiting the size 
and/or number of the impoundments, and covering the tailings with soil 
or keeping the tailings wet. These management practices form the basis 
of the work practice standards for conventional impoundments and 
continue to be very effective methods for limiting the amount of radon 
released to the environment.
    These work practice standards are a cost-effective method for 
reducing radon emissions from conventional impoundments. In addition, 
the liner requirements for conventional impoundments are also required 
by the NRC in their licensing requirements at 10 CFR part 40. 
Therefore, we are proposing that GACT for conventional impoundments 
will be the same work practice standards as were previously included in 
Subpart W.
3. Non-Conventional Impoundments Where Tailings Are Contained in Ponds 
and Covered by Liquids
    Today we are proposing a GACT standard specifically for use by any 
operating uranium recovery facility that has one or more non-
conventional impoundments at its facility (i.e., those impoundments 
where tailings are contained in ponds and covered by liquids). Common 
names for these structures may include, but are not limited to, 
impoundments, evaporation ponds and holding ponds. These ponds contain 
uranium byproduct material and the HAP emissions are regulated by 
Subpart W.
    Industry has argued in preambles to responses to the CAA section 
114(a) letters \32\ and elsewhere that Subpart W does not, and was 
never meant to, include these types of evaporation or holding ponds 
under the Subpart W requirements. Industry has asserted that the 
original Subpart W did not specifically reference evaporation or 
holding ponds but was regulating only conventional mill tailings 
impoundments. They argue that the ponds are temporary because they hold 
very little solid material but instead hold mostly liquids containing 
dissolved radionuclides (which emit very little radon), and at the end 
of the facility's life they are drained, and any solid materials, along 
with the liner system, are disposed in a properly licensed conventional 
impoundment.
---------------------------------------------------------------------------

    \32\ http://www.epa.gov/radiation/neshaps/subpartw/rulemaking-activity.html.
---------------------------------------------------------------------------

    EPA has consistently maintained that these non-conventional 
impoundments meet the existing applicability criteria for regulation 
under Subpart W. As defined at 40 CFR 61.251(g), uranium byproduct 
material or tailings means the waste produced by the extraction or 
concentration of uranium from any ore processed primarily for its 
source material content. The holding or evaporation ponds located at 
conventional mills, ISL facilities and potentially heap leach 
facilities contain uranium byproduct materials, either in solid form or 
dissolved in solution, and therefore their HAP emissions are regulated 
under Subpart W. Today we reiterate that position and are proposing a 
GACT standard more specifically tailored for these types of 
impoundments.
    We are proposing that these non-conventional impoundments (the 
evaporation or holding ponds) must maintain a liquid level in the 
impoundment of no less than one meter at all times during the operation 
of the impoundment. Maintaining this liquid level will ensure that 
radon-222 emissions from the uranium byproduct material in the pond are 
minimized. We are also proposing that there is no maximum area 
requirement for the size of these ponds since the chance of radon 
emissions is small. Our basis for this determination is that radon 
emissions from the pond will be expected to be very low since the 
liquid in the ponds acts as an effective barrier to radon emissions; 
given that radon-222 has a very short half-life (3.8 days), there 
simply is not enough time for approximately 98% of the radon produced 
by the solids or from the solution to migrate to the water surface and 
cross the water/air interface before decaying.
    By requiring a minimum of one meter of water in all nonconventional 
impoundments that contain uranium byproduct material, the release of 
radon from these impoundments would be greatly reduced. Nielson and 
Rogers (1986) present the following equation for calculating the radon 
attenuation:
[GRAPHIC] [TIFF OMITTED] TP02MY14.072

Where:

A = Radon attenuation factor (unit less)
[lambda] = Radon-222 decay constant (sec-\1\)
= 2.1x10-\6\ sec-\1\
D = Radon diffusion coefficient (cm\2\/sec)
= 0.003 cm\2\/sec in water
d = Depth of water (cm)
= 100 cm

    The above equation indicates that the attenuation of radon 
emanation by water (i.e., the amount by which a water cover will 
decrease the amount of radon emitted from the impoundment) depends on 
how quickly radon-222 decays, how quickly radon-222 can move through 
water (the diffusion coefficient), and the thickness of the layer of 
water.\33\ Solving the above equation shows that one meter of water has 
a radon attenuation factor of about 0.07. That is, emissions can be 
expected to be reduced by about 93% compared to no water cover.
---------------------------------------------------------------------------

    \33\ For a detailed discussion of this topic, which includes the 
effects of pond water mixing, wind and convection, please see ``Risk 
Assessment Revision for 40 CFR Part 61 Subpart W-Radon Emissions 
from Operating Mill Tailings, Task 5 Radon Emission from Evaporation 
Ponds,''(EPA-HQ-OAR-2008-0218-0080).
---------------------------------------------------------------------------

    The benefit incurred by this requirement is that significantly less 
radon will be released to the atmosphere. The amount varies from 
facility to facility based on the size of the nonconventional 
impoundment, but

[[Page 25403]]

across existing facilities radon can be expected to be reduced by 
approximately 24,600 curies, a decline of approximately 93%.
    The estimated cost associated with complying with the proposed one 
meter of liquid that would be required to limit the amount of radon 
emissions to the air vary according to the size of the impoundment and 
the geographic area in which it is located. We estimate that this 
requirement will cost owners or operators of 80 acre nonconventional 
impoundments between $1,042 and $9,687 per year. This value varies 
according to the location of the impoundment, which will determine 
evaporation rates, which determines how much replacement water will be 
required to maintain the minimum amount of one meter. If the evaporated 
water is not replaced by naturally occurring precipitation, then it 
would need to be replaced with make-up water supplied by the 
nonconventional impoundment's operator.
    The most obvious source of water is what is known as ``process 
water'' from the extraction of uranium from the subsurface. Indeed, 
management of this process water is one of the primary reasons for 
constructing the impoundment in the first place, as the process water 
contains uranium byproduct material that must also be managed by the 
facility. It is possible that an operator could maintain one meter of 
water in the impoundment solely through the use of process water. If 
so, this would not create any additional costs for the facility as the 
cost of the process water can be attributed to its use in the uranium 
extraction process. However, for purposes of estimating the economic 
impacts associated with our proposal, our cost estimate does not 
include process water as a source of water potentially added to the 
impoundment to replace water that has evaporated. Instead, we estimated 
the costs of using water from other sources. This method results in the 
most conservative cost estimate for compliance with the one meter 
requirement.
    In performing the cost impacts for this requirement, three 
potential sources of impoundment make-up water were considered: (1) 
Municipal water suppliers; (2) offsite non-drinking-water suppliers; 
and (3) on-site water (EPA-HQ-OAR-2008-0218-0087). Depending on the 
source of water chosen, we estimate that this requirement will cost 
owners or operators of nonconventional impoundments between $1,042.00 
and $9,687.00 per year.\34\
---------------------------------------------------------------------------

    \34\ Municipal sources were the most expensive, with average 
unit costs of $0.0033 per gallon. Offsite non-drinking water sources 
were the cheapest, at $0.000069 per gallon on average. Various 
references were used for the comparisons. For more detail, please 
see Section 6.3.3 of the Background Information Document.
---------------------------------------------------------------------------

    This value also varies according to the size and location of the 
nonconventional impoundment. Such impoundments currently range up to 80 
acres in size. The requirement to maintain a minimum of one meter of 
liquid in the ponds is estimated to cost approximately $0.03 per pound 
of uranium produced. The annual cost of makeup water was divided by the 
base case facility yellowcake annual production rate to calculate the 
makeup water cost per pound of yellowcake produced (EPA-HQ-OAR-2008-
0218-0087). We conclude that this proposed requirement is a cost-
effective way to significantly reduce radon emissions from 
nonconventional impoundments, and is therefore appropriate to propose 
as a GACT standard for nonconventional impoundments.
4. Heap Leach Piles
    The final affected source type for which we are proposing GACT 
standards is heap leach piles. While there are currently no operating 
uranium heap leach facilities in the United States, we are proposing to 
regulate the HAP emission at any future facilities using this type of 
uranium extraction under Subpart W since the moment that uranium 
extraction takes place in the heap, uranium byproduct materials are 
left behind. During the process of uranium extraction on a heap, as the 
acid drips through the ore, uranium is solubilized and carried away to 
the collection system where it is further processed. At the point of 
uranium movement out of the heap, what remains is uranium byproduct 
materials as defined by 40 CFR 61.251(g). In other words, what remains 
in the heap is the waste produced by the extraction or concentration of 
uranium from ore processed primarily for its source material content. 
Thus, Subpart W applies because uranium byproduct materials are being 
generated during and following the processing of the uranium ore in the 
heap.
    As a result, we are proposing GACT standards for heap leach piles. 
We are proposing that these piles conform to the phased disposal work 
practice standard specified for conventional impoundments in 40 CFR 
61.252(a)(1)(i)(which limits the number of active heap leach piles to 
two, and limits the size of each one to no more than 40 acres) and that 
the moisture content of the uranium byproduct material in the heap 
leach pile be greater than or equal to 30% moisture content. We believe 
that the phased disposal approach can be usefully applied here because 
it limits the amount of tailings that can be exposed at any one time, 
which limits the amount of radon that can be emitted. The phased 
disposal work practice standard is applicable for heap leach piles 
because heap leach piles are expected to be managed in a manner that is 
similar in many respects to conventional impoundments. Based on what we 
understand about the operation of potential future heap leach 
facilities, after the uranium has been removed from the heap leach 
pile, the uranium byproduct material that remains would be contained in 
the heap leach structure which would be lined according to the 
requirements of 40 CFR 192.32(a)(1). The heap leach pile would also be 
covered with soil at the end of its operational life to minimize radon 
emissions.
    This is what is required to occur at conventional impoundments 
using the phased disposal standard. Limiting the size of the operating 
heap leach pile to 40 acres or less (and the number of operating heap 
leach piles at any one time to two) has the same effect as it does on 
conventional impoundments; that is, it limits the area of exposed 
uranium byproduct material and therefore limits the radon emissions 
from the heap leach pile. While we believe that the 40 acre limitation 
is appropriate for heap leach piles, we are requesting comment on what 
should be the maximum size (area) of a heap leach pile.
    We are also proposing as GACT that the heap leach pile constantly 
maintain a moisture content of at least 30% by weight. By requiring a 
moisture content of at least 30%, the byproduct material in the heap 
leach pile will not become dewatered, and we think that the heap leach 
pile will be sufficiently saturated with liquid to reduce the amount of 
radon that can escape from the heap leach pile. However, we request 
further information on all the chemical mechanisms in place during the 
leaching operation, and whether the 30% moisture content is sufficient 
for minimizing radon emissions from the heap leach pile. We also 
request comment on the amount of time the 30% moisture requirement 
should be maintained by a facility. We are proposing the term 
``operational life'' of the facility. We are aware of several 
operations that take place during the

[[Page 25404]]

uranium extraction process at a heap leach pile. After an initial 
period of several months of allowing lixiviant to leach uranium from 
the pile, the heap leach pile is allowed to ``rest,'' which enables the 
geochemistry in the pile to equilibrate. At that point the heap leach 
pile may be subjected to another round of extraction by lixiviant, or 
it may be rinsed to flush out any remaining uranium that is in solution 
in the heap leach pile. After the rinsing, the pile is allowed to drain 
and a radon barrier required by 40 CFR 192.32 can be emplaced. We are 
proposing that the operational life of the heap leach pile be from the 
time that lixiviant is first placed on the heap leach pile until the 
time of the final rinse. We believe this incorporates a majority of the 
time when the heap leach pile is uncovered (no radon barrier has been 
constructed over the top of the heap) and when the ability for radon to 
be emitted is the greatest.
    Because there is no ``process water'' component to a heap leach 
operation, as there is for an ISL, water for the heap leach pile must 
be supplied from an outside source. Even if an ISL and heap leach 
operation were to be located at the same site, we consider it unlikely 
that an operator would use ISL process water as the basis for an acidic 
heap leach solution. It is possible, in fact likely, that the solution 
used in the heap will be recycled (i.e., applied to the heap more than 
once), which could reduce the amount of outside water needed to some 
degree, although as we discuss later in this section, it would not seem 
that recycling solution would affect the overall moisture content. In 
calculating the high-end costs of heap leaching, we have not included 
this possibility in our estimates of economic impacts.
    The unit costs for providing liquids to a heap leach pile are 
assumed to be the same as the unit costs developed for providing water 
to nonconventional impoundments. In estimating the cost impacts for 
this requirement, three potential sources of impoundment make-up water 
were considered: (1) Municipal water suppliers; (2) offsite non-
drinking-water suppliers; and (3) on-site water. The only cost 
associated with maintaining the moisture level within the pile is the 
cost of the liquid. We assume that existing piping used to supply 
lixiviant to the pile during leaching would be used to supply water 
necessary for maintaining the moisture level. Also, we assume that the 
facility will use the in-soil method for moisture monitoring. The in-
soil method and its costs are described below.
    Soil moisture sensors have been used for laboratory and outdoor 
testing 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.
    For example, one system would bury soil moisture sensors to the 
desired depth in the heap. Then, a portable soil moisture meter would 
be connected by cable to each buried sensor one at a time, i.e., a 
single meter can read any number of sensors. 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). Finally, it 
is assumed that moisture readings would be performed during the NRC 
required daily inspections of the heap leach pile, which would require 
approximately 2,000 additional work hours per year per facility. Our 
estimates for costs of monitoring the heap include 100 sensors located 
within the heap, with a meter on each sensor. We chose 100 sampling 
stations because heaps are generally the same size as conventional 
impoundments, and Method 115 prescribed 100 measurements for the 
tailings area of a conventional impoundment. The total estimated costs 
for using this system, including labor, are approximately $86,500 per 
year per facility.
    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, and a reading is taken. A handheld meter of 
this type costs about $1,065, and replacement rods about $58 for a 
pair. A minimum of 100 sampling stations for measuring radon could be 
required. We did not estimate costs for this method, as we concluded 
that the length of time required walking around a heap leach pile and 
obtaining these measurements required more time than is found in an 
average work day, and would expose workers to potentially hazardous 
constituents contained in the lixiviant.
    The base case heap leach facility includes a heap leach pile that 
will occupy up to 80 acres at a height of up to 50 feet. With an 
assumed porosity of 0.39 and a moisture content of 30% by weight, the 
effective surface area of the liquid within the heap pile is 33.7 
acres.
    Table 3 presents the calculated cost for make-up water to maintain 
the moisture level in the heap leach pile, such that the moisture 
content is at 30% by weight, or greater. The unit costs for water and 
the net evaporation rates used for these estimates are identical to 
those derived for evaporation ponds.

                                Table 3--Heap Leach Pile Annual Makeup Water Cost
----------------------------------------------------------------------------------------------------------------
                                                                        Net                        Makeup water
                    Cost type                     Water cost ($/    evaporation    Makeup water     rate  (gpm/
                                                       gal)           (in/yr)      cost  ($/yr)       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 make-up water in perspective, during leaching 
and rinsing of the heap leach pile, liquid is dripped onto the pile at 
a rate of 0.005 gallons per minute per square foot (gpm/ft\2\). This 
rate is significantly higher than the make-up water rates necessary to 
maintain the moisture content at 30% by weight, shown in Table 3. We 
conclude from this analysis that the leaching solution applied in a 
typical operation should be sufficient to maintain the moisture content 
of the heap leach pile to the required levels, and only in unusual 
circumstances (such as during the final rinse and draindown of the heap 
leach pile) would additional liquids need to be applied. However, in a 
circumstance that would require the additional application of liquid to 
maintain the 30% moisture limit, such as excessive evaporation, we 
estimate that the cost of requiring the owner/operator of a heap leach 
pile to maintain 30% moisture content in the pile will average 
approximately $4,000 per year.

[[Page 25405]]

    We are asking for comment on exactly where in the pile the 30% 
moisture content should be achieved. We are also soliciting comments on 
whether the leaching operation itself liberates more radon into the air 
than the equivalent of a conventional impoundment. We assume that 
because low-grade ore is usually processed by heap leach, there would 
be less radon emitted from a heap leach pile than from a conventional 
impoundment of similar size. We request information on whether this is 
a correct assumption.
    We are also aware that there could be a competing argument against 
regulating the heap leach pile under Subpart W while the lixiviant is 
being placed on the heap leach pile. While not directly correlative, 
the process of heap leach could be defined as active ``milling.'' The 
procedure being carried out on the heap is the extraction of uranium. 
In this view, the operation is focused on the production of uranium 
rather than on managing uranium byproduct materials. Therefore, under 
this view, the heap meets the definition of tailings under 40 CFR 
61.251(g) only after the final rinse of the heap solutions occurs and 
the heap is preparing to close. In this scenario the heap leach pile 
would close under the requirements at 40 CFR part 192.32 and Subpart W 
would never apply. We are requesting comments on the relative merits of 
this interpretation.
    It bears noting that, as with ISL facilities, collection and/or 
evaporation ponds (nonconventional impoundments) may exist at heap 
leach facilities that will also contain uranium byproduct materials. 
These ponds' HAP emissions will be regulated under Subpart W regardless 
of whether the heap leach pile is also subject to regulation under that 
subpart.

V. Other Issues Generated by Our Review of Subpart W

    During our review of Subpart W we also identified several issues 
that need clarification in order to be more fully understood. The 
issues that we have identified are:
     Clarification of the term ``standby'' and how it relates 
to the operational phase of an impoundment;
     Amending the definition of ``operation'' of an impoundment 
so that it is clear when the owner or operator is subject to the 
requirements of Subpart W;
     Determining whether Subpart W adequately addresses 
protection from extreme weather events;
     Revising 40 CFR 61.252(b) and (c) to accurately reflect 
that it is only 40 CFR 192.32(a)(1)that is applicable to Subpart W; and
     Removing the phrase ``as determined by the Nuclear 
Regulatory Commission'' in 40 CFR 61.252(b)(1) and (2).

A. Clarification of the Term ``Standby''

    There has been some confusion over whether the requirements of 
Subpart W apply to an impoundment that is in ``standby'' mode. This is 
the period of time that an impoundment may not be accepting tailings, 
but has not yet entered the ``closure period'' as defined by 40 CFR 
192.31(h). This period of time usually takes place when the price of 
uranium is such that it may not be cost effective for the uranium 
recovery facility to continue operations, and yet the facility has not 
surrendered its operating license, and may re-establish operations once 
the price of uranium rises to a point where it is cost effective to do 
so. Since the impoundment has not entered the closure period, it could 
continue to accept tailings at any time; therefore, Subpart W 
requirements continue to apply to the impoundment.
Today we are proposing to add a definition to 40 CFR 61.251 to define 
``standby'' as:

    Standby means the period of time that an impoundment may not be 
accepting uranium byproduct materials but has not yet entered the 
closure period.

B. Amending the Definition of ``Operation'' for a Conventional 
Impoundment

    As currently written, 40 CFR 61.251(e) defines the operational 
period of a tailings impoundment. It states that ``operation'' means 
that an impoundment 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 some 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 definition. 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 material 
(liners, deconstruction 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 
disposing of new tailings in the impoundment, it has not begun closure 
activities; therefore, the impoundment is still open to disposal of 
byproduct material that emits radon and continues to be subject to all 
applicable Subpart W requirements.
    To prevent future confusion, we are proposing today to amend the 
definition of ``operation'' in the Subpart W definitions at 40 CFR 
61.251 as follows:

    Operation means that an impoundment 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.

C. Weather Events

    In the past, uranium recovery facilities have been located in the 
western regions of the United States. In these areas, the annual 
precipitation falling on the impoundment, and any drainage area 
contributing surface runoff to the impoundment, has usually been less 
than the annual evaporation from the impoundment. Also, these 
facilities have been located away from regions of the country where 
extreme rainfall events (e.g., hurricanes or flooding) could jeopardize 
the structural integrity of the impoundment, although there is a 
potential for these facilities to be affected by flash floods, 
tornadoes, etc. Now, however, uranium exploration and recovery in the 
U.S. has the potential to move eastward, into more climatologically 
temperate regions of the country, with south central Virginia being 
considered for a conventional uranium mill. In determining whether 
additional measures would be needed for impoundments operating in areas 
where precipitation exceeds evaporation, a review of the existing 
requirements was necessary.
    The proposed revisions to Subpart W will continue to require owners 
and operators of all impoundments to follow the requirements of 40 CFR 
192.32(a)(1). That particular regulation references the RCRA surface 
impoundment design and operations requirements of 40 CFR 264.221. At 40 
CFR 264.221(g) and (h) are requirements that ensure proper design and 
operation of tailings impoundments. Section 264.221(g) states that 
impoundments must be designed, constructed, maintained and operated to 
prevent overtopping resulting from normal or abnormal operations; 
overfilling; wind and rain action (e.g., a two foot freeboard 
requirement); rainfall; run-on;

[[Page 25406]]

malfunctions of level controllers, alarms and other equipment; and 
human error. Section 264.221(h) states that impoundments must have 
dikes that are designed, constructed and maintained with sufficient 
structural integrity to prevent massive failure of the dikes. In 
ensuring structural integrity, it must not be presumed that the liner 
system will function without leakage during the active life of the 
unit.
    Since impoundments at uranium recovery facilities have been and 
will continue to be required to comply with the requirements of 40 CFR 
192.32(a)(1), they are already required to be designed to prevent 
failure during extreme weather events. As we stated in Section IV B.2., 
we believe the requirements of 40 CFR 192.32(a)(1) contain enough 
safeguards to allow for the placement of tailings and yet provide an 
early warning system in the event of a leak in the liner system. 
Therefore, we are proposing to include these requirements in the 
Subpart W requirements without modification.

D. Applicability of 40 CFR 192.32(a) to Subpart W

    The requirements at 40 CFR 61.252(b) and (c) require compliance 
with 40 CFR 192.32(a). However, we are now proposing to focus the 
Subpart W requirements on the impoundment design and construction 
requirements found specifically at 40 CFR 192.32(a)(1). The remainder 
of 40 CFR 192.32(a) goes beyond this limited scope by including 
requirements for ground-water detection monitoring systems and closure 
of operating impoundments. These other requirements, along with all of 
the part 192 standards, are implemented and enforced by the NRC through 
its licensing requirements for uranium recovery facilities at 10 CFR 
part 40, Appendix A. However, when referenced in Subpart W, the 
requirements in 40 CFR 192.32(a)(1) would also be implemented and 
enforced by EPA as the regulatory authority administering Subpart W 
under its CAA authority. Therefore today we are proposing to revise 40 
CFR 61.252 (b) and (c) to specifically define which portions of 40 CFR 
192.32(a) are applicable to Subpart W. At the same time we are 
proposing to eliminate the phrase ``. . .as determined by the Nuclear 
Regulatory Commission'' from 40 CFR 61.252(b). This should eliminate 
confusion regarding what an applicant must submit to EPA under the CAA 
in its pre-construction and modification approval applications as 
required by 40 CFR 61.07, and better explain that EPA is the regulatory 
agency administering Subpart W under the CAA. This proposed change will 
have no effect on the licensing requirements of the NRC or its 
regulatory authority under UMTRCA to implement the part 192 standards 
through its licenses.

VI. Summary of Environmental, Cost and Economic Impacts

    As discussed earlier, uranium recovery activities are carried out 
at several different types of facilities. We are proposing to revise 
Subpart W based on how uranium recovery facilities manage uranium 
byproduct materials during and after the processing of uranium ore at 
their particular facility. As discussed in Sections III and IV, we are 
proposing GACT requirements for three types of affected sources at 
uranium recovery facilities: (1) Conventional impoundments; (2) 
nonconventional impoundments; and (3) heap leach piles.
    For purposes of analyzing the impacts of the proposed rule, we 
assumed that approximately five conventional milling facilities, 50 ISL 
facilities (although this is only a projection since only 12 currently 
exist) and one heap leach facility, each with at least one regulated 
impoundment, would become subject to the proposed rule. The following 
sections present our estimates of the proposed rule's air quality, cost 
and economic impacts. For more information, please refer to the 
Economic Impact Analysis report that is included in the public docket 
for this proposed rule (EPA-HQ-OAR-2008-0218-0087).

A. What are the air quality impacts?

    We project that the proposed requirements will maintain or improve 
air quality surrounding the regulated facilities. The GACT standards 
being proposed today are based on control technologies and management 
practices that have been used at uranium recovery facilities for the 
past twenty or more years. These standards will minimize the amount of 
radon that is released to the air by keeping the impoundments wet or 
covered with soil and/or by limiting the area of exposed tailings. The 
requirements in this proposed rule should eliminate or reduce radon 
emissions at all three types of affected sources.

B. What are the cost and economic impacts?

    Table 24 presents a summary of the unit cost (per pound of 
U3O8) for implementing each GACT at each of the 
three types of uranium recovery facilities. In addition to presenting 
the GACT costs individually, Table 24 presents the total unit cost to 
implement all relevant GACTs at each type of facility.
    A reference facility for each type of uranium recovery facility is 
developed and described in Section 6.2, including the base cost 
estimate to construct and operate (without the GACTs) each of the three 
types of reference facilities. For comparison purposes, the unit cost 
(per pound of U3O8) of the three uranium recovery 
reference facilities is presented at the bottom of Table 4.

                      Table 4--Proposed GACT Standards Costs per Pound of U[ihel3]O[ihel8]
----------------------------------------------------------------------------------------------------------------
                                                                         Unit cost ($/lb U[ihel3]O[ihel8])
                                                                 -----------------------------------------------
                                                                   Conventional         ISL         Heap leach
----------------------------------------------------------------------------------------------------------------
GACT--Double Liners for Nonconventional Impoundments............          $1.04           $3.07          $0.22
GACT--Maintaining 1 Meter of Water in Nonconventional                      0.013           0.010          0.0010
 Impoundments...................................................
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 information in Table 24, implementing all four GACTs 
would result in unit cost (per pound of U3O8) 
increases of about 2%, 6%, and 5% at conventional, ISL, and heap leach 
type uranium recovery facilities, respectively.
    The baseline costs were estimated using recently published cost 
data for actual uranium recovery facilities. For the model conventional 
mill, we used

[[Page 25407]]

data from the recently licensed new mill at the Pi[ntilde]on Ridge 
project in Colorado. For the model ISL facility, we used data from two 
proposed new facilities: (1) The Centennial Uranium project in 
Colorado; and (2) the Dewey-Burdock project in South Dakota. The 
Centennial project is expected to have a 14- to 15-year production 
period, which is a long duration for an ISL facility, while the Dewey-
Burdock project is expected to have a shorter production period of 
about 9 years, which is more representative of ISL facilities. For the 
heap leach facility, we used data from the proposed Sheep Mountain 
project in Wyoming.
    Existing Subpart W required facilities to perform annual monitoring 
using Method 115 to demonstrate that the radon flux standard at 
conventional impoundments constructed before December 15, 1989 was 
below 20 pCi/m\2\-sec. The proposed removal of this monitoring 
requirement would result in a cost saving to the three facilities for 
which this requirement still applies: (1) Sweetwater; (2) White Mesa; 
and (3) Shootaring Canyon. Method 115 requires 100 measurements as the 
minimum number of flux measurements considered necessary to determine a 
representative mean radon flux value. For the three sites that are 
still required to perform Method 115 radon flux monitoring, the average 
annual cost to perform that monitoring is estimated to be about $9,730 
for Shootaring and Sweetwater, and $19,460 for White Mesa. For all 
three sites the total annual average cost is estimated to be $38,920 
per year, with a range from approximately $28,000 to $49,500 per year. 
For all three sites the total annual average cost savings resulting 
from removal of the flux monitoring requirement would be $39,920.
    Baseline costs (explained in Section IV.B) for conventional 
impoundment liner construction \35\ will remain the same, since the 
proposed rule does not impose additional requirements. Liners meeting 
the requirements at 40 CFR 192.32(a)(1) are already mandated by other 
regulations and, therefore, built into the baseline cost estimate. 
Therefore there are consequently no costs (or benefits) resulting from 
the inclusion of these requirements in Subpart W.
---------------------------------------------------------------------------

    \35\ These liner systems (conventional, nonconventional and heap 
leach piles)are already required by 40 CFR 192.32(a)(1), which, as 
explained above, are requirements promulgated by EPA under UMTRCA 
that are incorporated into NRC regulations and implemented and 
enforced by NRC through their licensing requirements. Therefore, we 
are not placing any additional liner requirements on facilities or 
requiring them to incur any additional costs to build their 
conventional or nonconventional impoundments or heap leach piles 
above and beyond what an owner or operator of these impoundments 
must already incur to obtain an NRC license. Therefore, there are no 
projected costs (or benefits) beyond the baseline resulting from the 
inclusion of these requirements in Subpart W.
---------------------------------------------------------------------------

    The average cost to construct one of these impoundments is $13.8 
million. We estimate that this cost is approximately 3% of the total 
baseline capital costs to construct a conventional mill, estimated at 
$372 million.
    We have estimated that for an average 80 acre nonconventional 
impoundment the average cost of construction of an impoundment is $23.7 
million. Requiring impoundments to comply with the liner requirements 
in 40 CFR 192.32(a)(1) will contain the uranium byproduct material and 
reduce the potential for ground water contamination. The only economic 
impact attributable to the proposed rule is the cost of complying with 
the new requirement to maintain a minimum of one meter of water in the 
nonconventional impoundments during operation and standby. As shown in 
Section IV.B.3. of this preamble, as long as approximately one meter of 
water is maintained in the nonconventional impoundments the effective 
radon emissions from the ponds are so low that it is difficult to 
determine if there is any contribution above background radon values. 
In order to maintain one meter of liquid within a pond, it is necessary 
to replace the water that is evaporated from the pond. Depending on the 
source of water chosen,\36\ we estimate that this requirement will cost 
owners or operators of nonconventional impoundments between $1,042 and 
$9,687 per year. This value also varies according to the size of the 
nonconventional impoundment, up to 80 acres, and the location of the 
impoundment. Evaporation rates vary by geographic location. However, 
the cost to maintain the one meter of liquid in a nonconventional 
impoundment is estimated to be less than 1% of the total annual 
production costs, estimated at $23.7 million. The requirement to 
maintain a minimum of one meter of liquid in the ponds is estimated to 
cost approximately $0.03 per pound of uranium produced.
---------------------------------------------------------------------------

    \36\ Municipal sources were the most expensive, with average 
unit costs of $0.0033 per gallon. Offsite non-drinking water sources 
were the cheapest, at $0.000069 per gallon on average. For more 
detail, please see Section 6.3.3 of the Background Information 
Document.
---------------------------------------------------------------------------

    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 drainage 
collection capabilities, be provided under heap leach piles. Baseline 
costs (explained in Section IV.B) for heap leach pile liner 
construction will remain the same, since the proposed rule does not 
impose additional requirements. Liners meeting the requirements at 40 
CFR 192.32(a)(1) are already mandated by other regulations and, 
therefore, built into the baseline cost estimate. Therefore there are 
consequently no costs (or benefits) resulting from the inclusion of 
these requirements in Subpart W. Baseline costs for construction will 
be essentially the same as for conventional impoundments. Since the 
liner systems are equivalent to the systems used for conventional and 
nonconventional impoundments, we have been able to estimate the average 
costs associated with the construction of heap leach pile impoundments 
that meet the liner requirements we are proposing, and compare them to 
the costs associated with the total production of uranium produced by 
the facility. The average cost of constructing such an impoundment is 
estimated to be approximately $15.3 million. The costs of constructing 
this type of liner system are about 4% of the estimated total baseline 
capital costs of a heap leach facility estimated at $356 million.
    For heap leach piles, when the soil moisture content in the heap 
leach pile falls below about 30% by weight, the radon flux out of the 
heap leach pile increases because radon moves through the air faster 
(with less opportunity to decay) than through water. We concluded from 
our analysis that the leaching solution applied in a typical operation 
should be sufficient to maintain the moisture content of the heap leach 
pile to the required levels, and only in unusual circumstances would 
additional liquids need to be applied. However, in a circumstance that 
would require the additional application of liquid to maintain the 30% 
moisture limit, such as excessive evaporation, we estimate that the 
cost of requiring the owner/operator of a heap leach pile to maintain 
30% moisture content in the pile will average approximately $4,000 per 
year. We also estimate that it will cost approximately $86,500 per year 
(which includes labor of approximately 2,000 hours) to perform the 
tests required to verify that the moisture content is being maintained. 
These costs are less than one percent of the total baseline capital 
costs of a heap leach facility, estimated at $356 million.

[[Page 25408]]

    In summary, we estimate that for conventional impoundments there 
will be no additional costs incurred through this proposed rule. There 
will be a cost savings of approximately $39,900 per year for the three 
existing conventional impoundments that are currently required to 
monitor for radon flux through the use of Method 115, since we are 
proposing to eliminate this requirement. For nonconventional 
impoundments we estimate that the additional costs incurred by this 
proposed rule will be to maintain one meter of liquid in each 
nonconventional impoundment, and we have estimated those costs between 
approximately $1,040 and $9,680 per year. For heap leach piles, 
additional costs incurred by this proposed rule would be for the 
maintaining and monitoring of the continuous 30% moisture content 
requirement, which we estimate will impose a one-time cost of 
approximately $35,000 for equipment and approximately $86,000 per year 
to monitor the moisture content.

C. What are the non-air environmental impacts?

    Water quality would be maintained by implementation of this 
proposed rule. This proposed rule does contain requirements (by 
reference) related to water discharges and spill containment. In fact, 
the liner requirements cross referenced at 40 CFR 192.32(a)(1) will 
significantly decrease the possibility of contaminated liquids leaking 
from impoundments into ground water (which can be a significant source 
of drinking water). Section 192.32(a)(1) includes a cross-reference to 
the surface impoundment design and construction requirements of 
hazardous waste surface impoundments regulated under the Resource 
Conservation and Recovery Act (RCRA), found at 40 CFR 264.221. Those 
requirements state that the impoundment shall be designed, constructed 
and installed to prevent any migration of wastes out of the impoundment 
to the adjacent subsurface soil or ground water or surface water at any 
time during the active life of the impoundment. There are other 
requirements for the design and operation of the impoundment, and these 
include construction specifications, slope requirements, sump and 
liquid removal requirements.
    These liner systems (conventional, nonconventional and heap leach 
piles)are already required by 40 CFR 192.32(a)(1), which, as explained 
above, are requirements promulgated by EPA under UMTRCA that are 
incorporated into NRC regulations and implemented and enforced by NRC 
through their licensing requirements. Therefore, we are not placing any 
additional liner requirements on facilities or requiring them to incur 
any additional costs to build their conventional or nonconventional 
impoundments or heap leach piles above and beyond what an owner or 
operator of these impoundments must already incur to obtain an NRC 
license.
    Including a double liner in the design of all onsite impoundments 
that would contain uranium byproduct material would reduce the 
potential for ground-water contamination. Although the amount of the 
potential reduction is not quantifiable, it is important to take this 
into consideration due to the significant use of ground water as a 
source of drinking water.

VII. Statutory and Executive Orders Review

A. Executive Order 12866: Regulatory Planning and Review and Executive 
Order 13563: Improving Regulation and Regulatory Review

    Under Executive Order 12866 (58 FR 51735, October 4, 1993), this 
action is a ``significant regulatory action.'' The Executive Order 
defines ``significant regulatory action'' as one that is likely to 
result in a rule that may ``raise novel legal or policy issues arising 
out of legal mandates, the President's priorities, or the principles 
set forth in the Executive Order.'' Accordingly, EPA submitted this 
action to the Office of Management and Budget (OMB) for review under 
Executive Orders 12866 and 13563 (76 FR 3821, January 21, 2011) and any 
changes made in response to OMB recommendations have been documented in 
the docket for this action.

B. Paperwork Reduction Act

    The information collection requirements in this proposed rule have 
been submitted for approval to the Office of Management and Budget 
(OMB) under the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. The 
Information Collection Request (ICR) document prepared by EPA has been 
assigned EPA ICR number 2464.01.
    The information to be collected for the proposed rulemaking today 
is based on the requirements of the Clean Air Act. Section 114 
authorizes the Administrator of EPA to require any person who owns or 
operates any emission source or who is subject to any requirements of 
the Act to:

--Establish and maintain records
--Make reports, install, use, and maintain monitoring equipment or 
method
--Sample emissions in accordance with EPA-prescribed locations, 
intervals and methods
--Provide information as may be requested

    EPA's regional offices use the information collected to ensure that 
public health continues to be protected from the hazards of 
radionuclides by compliance with health based standards and/or 
Generally Available Control Technology (GACT).
    The proposed rule would require the owner or operator of a uranium 
recovery facility to maintain records that confirm that the 
conventional impoundment(s), nonconventional impoundment(s) and heap 
leach pile(s) meet the requirements in section 192.32(a)(1). Included 
in these records are the results of liner compatibility tests, 
measurements confirming that one meter of liquid has been maintained in 
nonconventional impoundments and records confirming that heap leach 
piles have constantly maintained at least 30% moisture content during 
the operating life of the heap leach pile. This documentation should be 
sufficient to allow an independent auditor (such as an EPA inspector) 
to verify the accuracy of the determination made concerning the 
facility's compliance with the standard. These records must be kept at 
the mill or facility for the operational life of the facility and, upon 
request, be made available for inspection by the Administrator, or his/
her authorized representative. The proposed rule would not require the 
owners or operators of operating impoundments and heap leach piles to 
report the results of the compliance inspections or calculations 
required in Section 61.255. The recordkeeping requirements require only 
the specific information needed to determine compliance. We have taken 
this step to minimize the reporting requirements for small business 
facilities.
    The annual proposed monitoring and recordkeeping burden to affected 
sources for this collection (averaged over the first three years after 
the effective date of the proposed rule) is estimated to be 10,400 
hours with a total annual cost of $400,000. This estimate includes a 
total capital and start-up cost component annualized over the 
facility's expected useful life, a total operation and maintenance 
component, and a purchase of services component. We estimate that this 
total burden will be spread over 21 facilities that will be required to 
keep records. Of this total burden, however, 4,150 hours (and $93,000) 
will be incurred by the one heap leach uranium recovery facility,

[[Page 25409]]

due to the requirements for purchasing, installing and monitoring the 
soil moisture sensors, as well as training staff on how to operate the 
equipment.
    Burden is defined at 5 CFR 1320.3(b). An agency may not conduct or 
sponsor, and a person is not required to respond to, a collection of 
information unless it displays a currently valid OMB control number. 
The OMB control numbers for EPA's regulations in 40 CFR are listed in 
40 CFR part 9.
    To comment on the Agency's need for this information, the accuracy 
of the provided burden estimates, and any suggested methods for 
minimizing respondent burden, EPA has established a public docket for 
this rule, which includes this ICR, under Docket ID number EPA-HQ-OAR-
2008-0218. Submit any comments related to the ICR to EPA and OMB. See 
ADDRESSES section at the beginning of this notice for where to submit 
comments to EPA. Send comments on the ICR to OMB to the Office of 
Information and Regulatory Affairs, Office of Management and Budget, 
725 17th Street NW., Washington, DC 20503, Attention: Desk Office for 
EPA. Since OMB is required to make a decision concerning the ICR 
between 30 and 60 days after May 2, 2014, a comment to OMB is best 
assured of having its full effect if OMB receives it by June 2, 2014. 
The final rule will respond to any OMB or public comments on the 
information collection requirements contained in this proposal.

C. Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA) generally requires an agency 
to prepare a regulatory flexibility analysis of any rule subject to 
notice and comment rulemaking requirements under the Administrative 
Procedure Act or any other statute unless the agency certifies that the 
rule will not have a significant economic impact on a substantial 
number of small entities. Small entities include small businesses, 
small organizations, and small governmental jurisdictions.
    For purposes of assessing the impacts of today's rule on small 
entities, small entity is defined as: (1) A small business whose 
company has less than 500 employees and is primarily engaged in 
leaching or beneficiation of uranium, radium or vanadium ores as 
defined by NAIC code 212291; (2) a small governmental jurisdiction that 
is a government of a city, county, town, school district or special 
district with a population of less than 50,000; and (3) a small 
organization that is any not-for-profit enterprise which is 
independently owned and operated and is not dominant in its field.
    After considering the economic impacts of this proposed rule on 
small entities, I certify that this action will not have a significant 
economic impact on a substantial number of small entities. This 
proposed rule is estimated to impact approximately 18 uranium recovery 
facilities that are currently operating or plan to operate in the 
future.
    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 facilities that use conventional 
milling techniques proposes that only phased disposal units or 
continuous disposal units be used to manage the tailings. For either 
option, the disposal unit must be lined and equipped with a leak 
detection system, designed in accordance with part 192.32(a)(1). 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 disposal is chosen, no more than 10 acres may be 
open at any given time. Finally, the Agency is proposing to eliminate 
the distinction that was made in the 1989 rule between impoundments 
constructed pre-1989 and post-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 on an annual basis to demonstrate that the average 
Rn-222 flux does not exceed 20 pCi/m\2\/sec.
    The conventional milling GACT applies to three existing mills and 
one proposed mill that is in the process of being licensed. The four 
conventional mills are: the White Mesa mill owned by Energy Fuels 
Resources (USA); the Shootaring Canyon mill owned by Uranium One, Inc.; 
the Sweetwater mill owned by Kennecott Uranium Co.; and the proposed 
Pi[ntilde]on Ridge mill owned by Energy Fuels, Inc. Of the three 
companies that own conventional mills, none are classified as small 
businesses using fewer than 500 employees as the classification 
criterion.
    Energy Fuels White Mesa mill uses a phased disposal system that 
complies with the proposed GACT. When its existing open unit is full it 
will be contoured and covered and a new unit, constructed in accordance 
with the proposed GACT, will be opened to accept future tailings. 
Energy Fuels is proposing a phased disposal system to manage its 
tailings; this system also complies with the proposed GACT.
    Based on the fact that both small entities are in compliance with 
the proposed GACT, we conclude that the rulemaking will not impose any 
new economic impacts on either facility. For Energy Fuels Mines, the 
proposed rule will actually result in a cost saving as it 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 part 192.32(a)(1) and that a minimum of 1 meter 
of liquid be maintained in the ponds during operation and standby. The 
key design requirements for the ponds are for a double-liner with a 
leak detection system between the two liners.
    In addition to the four conventional mills identified above, the 
GACT for evaporation ponds applies to in-situ leach facilities and heap 
leach facilities. Currently, there are five operating ISL facilities 
and no operating heap leach facilities. The operating ISLs are Crow 
Butte and Smith Ranch owned by Cameco Resources, Alta Mesa owned by 
Mestena Uranium, LLC, Willow Creek owned by Uranium One, Inc., and 
Hobson owned by Uranium Energy Corp. Again using the fewer than 500 
employees' criterion, Mestena Uranium, LLC and Uranium Energy Corp are 
both small businesses, while Cameco Resources and Uranium One, Inc. are 
both large businesses.
    All of the evaporation ponds at the four conventional mills and the 
five ISL facilities were built in conformance with part 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 standby.
    The proposed revisions to Subpart W apply to five currently 
operating ISL facilities. The operating facilities are Crow Butte 
(Nebraska) and Smith Ranch (Wyoming), owned by Cameco Resources; Alta 
Mesa (Texas), owned by Mestena Uranium, LLC; Willow Creek (Wyoming), 
owned by Uranium One, Inc.; and Hobson (Texas), owned by Uranium Energy 
Corp. Again using the fewer than 500 employees' criterion, Mestena 
Uranium, LLC and Uranium Energy Corp are both small businesses, while 
Cameco Resources and Uranium One, Inc. are both large businesses.

[[Page 25410]]

    In addition to the five operating ISL facilities, three additional 
ISL facilities have been licensed, all in the state of Wyoming. These 
are: Lost Creek, owned by Ur-Energy Inc.; Moore Ranch, owned by Uranium 
One, Inc.; and Nichols Ranch, owned by Uranerz Uranium Corp. Of these 
three companies, both Ur-Energy Inc. and Uranerz Uranium Corp. are 
small businesses.
    Eleven other ISL facilities have been proposed for licensing. These 
include: Dewey-Burdock (South Dakota) and Centennial (Colorado), both 
owned by Powertech Uranium Corp.; and Kingsville Dome, Los Finados, 
Rosito, and Vasques (Texas), all owned by Uranium Resources Inc.; 
Crownpoint (New Mexico), also owned by Uranium Resources Inc., Church 
Rock (New Mexico), owned by Strathmore Minerals; Ross (Wyoming), owned 
by Strata Energy, Inc., Goliad (Texas), owned by Uranium Energy Corp.; 
and Antelope-Jab (Wyoming), owned by Uranium One, Inc. All of these 
companies, except for Uranium One, Inc. are small businesses.
    According to the licensing documents submitted by the owners of the 
proposed ISL facilities, all will be constructed in conformance with 
part 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 standby.
    The requirement to maintain a minimum of 1 meter of liquid in the 
ponds is estimated to cost up to $0.03 per pound of 
U3O8 produced. This cost is not a significant 
impact on any of these small entities.
    Although there are no heap leach facilities currently licensed, 
Energy Fuels, Inc. is expected to submit a licensing application for 
the Sheep Mountain Project. From the preliminary documentation that 
Titan presented (now owned by Energy Fuels), the facility will have an 
Evaporation Pond, a Collection Pond, and a Raffinate Pond. All three 
ponds will be double lined with leak detection. However, as Energy 
Fuels is a large business, it does not affect the determination of 
impacts on small businesses.
    The GACT for heap leach facilities applies the phased disposal 
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 during operations.
    As noted previously, there are no heap leach facilities currently 
in existence, and the only one that is known to be preparing to submit 
a license application is being proposed by Energy Fuels, which is a 
large business.
    Of the 20 facilities identified above, 15 are owned by small 
businesses. No small organizations or small governmental entities have 
been identified that would be impacted by the proposed GACTs. We 
continue to be interested in the potential impacts of the proposed rule 
on small entities and welcome comments on issues related to such 
impacts.

D. Unfunded Mandates Reform Act

    This rule does not contain a Federal mandate that may result in 
expenditures of $100 million or more for State, local and tribal 
governments, in the aggregate, or the private sector in any one year. 
The proposed rule imposes no enforceable duties on any State, local or 
Tribal governments or the private sector. Thus, this rule is not 
subject to the requirements of sections 202 or 205 of UMRA.
    This rule is also not subject to the requirements of section 203 of 
UMRA because it contains no regulatory requirements that might 
significantly or uniquely affect small governments because it contains 
no requirements that apply to such governments nor does it impose 
obligations upon them.

E. Executive Order 13132: Federalism

    This proposed rule does not have federalism implications. It will 
not have substantial direct effects on the States, on the relationship 
between the national government and the States, or on the distribution 
of power and responsibilities among the various levels of government, 
as specified in Executive Order 13132. None of the facilities subject 
to this action are owned and operated by State governments, and, 
nothing in the proposed rule will supersede State regulations. Thus, 
Executive Order 13132 does not apply to this proposed rule.
    In the spirit of Executive Order 13132 and consistent with EPA 
policy to promote communications between EPA and State and local 
governments, EPA specifically solicits comment on this proposed rule 
from State and local officials.

F. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    This action does not have tribal implications, as specified in 
Executive Order 13175 (65 FR 67249, November 9, 2000). The action 
imposes requirements on owners and operators of specified area sources 
and not tribal governments. Thus, Executive Order 13175 does not apply 
to this action.
    EPA specifically solicits additional comment on this proposed 
action from tribal officials.

G. Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks

    EPA interprets EO 13045 (62 FR 19885, April 23, 1997) as applying 
to those regulatory actions that concern health or safety risks, such 
that the analysis required under section 5-501 of the Order has the 
potential to influence the regulation. This action is not subject to EO 
13045 because it is based solely on technology performance.

H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use

    This action is not a ``significant energy action'' as defined in 
Executive Order 13211 (66 FR 28355 (May 22, 2001)), because it is not 
likely to have a significant adverse effect on the supply, 
distribution, or use of energy. This proposed rule will not adversely 
directly affect productivity, competition, or prices in the energy 
sector.

I. National Technology Transfer and Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (``NTTAA''), Public Law 104-113, 12(d) (15 U.S.C. 272 note) 
directs EPA to use voluntary consensus standards in its regulatory 
activities unless to do so would be inconsistent with applicable law or 
otherwise impractical. Voluntary consensus standards are technical 
standards (e.g., materials specifications, test methods, sampling 
procedures, and business practices) that are developed or adopted by 
voluntary consensus standards bodies. NTTAA directs EPA to provide 
Congress, through OMB, explanations when the Agency decides not to use 
available and applicable voluntary consensus standards. This proposed 
rulemaking does not involve technical standards. Therefore, EPA is not 
considering the use of any voluntary consensus standards.
    We request public comment on this aspect of the proposed 
rulemaking, and specifically, ask you to identify potentially 
applicable voluntary consensus standards and to explain why such 
standards could be used in this regulation.

[[Page 25411]]

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations

    Executive Order 12898 (59 FR 7629 (Feb. 16, 1994)) establishes 
federal executive policy on environmental justice. Its main provision 
directs federal agencies, to the greatest extent practicable and 
permitted by law, to make environmental justice part of their mission 
by identifying and addressing, as appropriate, disproportionately high 
and adverse human health or environmental effects of their programs, 
policies, and activities on minority populations and low-income 
populations in the United States.
    EPA has determined that this proposed rule will not have 
disproportionately high and adverse human health or environmental 
effects on minority or low-income populations because it increases the 
level of environmental protection for all affected populations without 
having any disproportionately high and adverse human health or 
environmental effects on any population, including any minority or low-
income population. This proposed rule would reduce toxics emissions of 
radon from nonconventional impoundments and heap leach piles and thus 
decrease the amount of such emissions to which all affected populations 
are exposed.

List of Subjects in 40 CFR Part 61

    Environmental protection, Air pollution control, Hazardous 
substances, Radon, Tailings, Byproduct, Uranium, Reporting and 
recordkeeping requirements.

    Dated: April 17, 2014.
Gina McCarthy,
Administrator.
    For the reasons stated in the preamble, the Environmental 
Protection Agency proposes to amend title 40, Chapter I of the Code of 
Federal Regulations as follows:

PART 61--[NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS]

0
1. The authority citation for part 61 continues to read as follows:

    Authority:  42 U.S.C. 7401 et seq.

Subpart W--[National Emission Standards for Radon Emissions From 
Operating Mill Tailings]

0
2. Section 61.251 is amended by revising the definition for (e) and 
adding new definitions for (h-m) as follows:

Sec.  61.251  Definitions.

* * * * *
    (e) Operation. Operation means that an impoundment is being used 
for the continued placement of uranium byproduct materials 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.
* * * * *
    (h) Conventional Impoundment. A conventional impoundment is a 
permanent structure located at any uranium recovery facility which 
contains mostly solid uranium byproduct material from the extraction of 
uranium from uranium ore. These impoundments are left in place at 
facility closure.
    (i) Non-Conventional Impoundment. A non-conventional impoundment 
can be located at any uranium recovery facility and contains uranium 
byproduct material suspended in and/or covered by liquids. These 
structures are commonly known as holding ponds or evaporation ponds. 
They are removed at facility closure.
    (j) Heap Leach Pile. A heap leach pile is a pile of uranium ore 
placed on an engineered structure and stacked so as to allow uranium to 
be dissolved and removed by leaching liquids.
    (k) Standby. Standby means the period of time that an impoundment 
may not be accepting uranium byproduct materials but has not yet 
entered the closure period.
    (l) Uranium Recovery Facility. A uranium recovery facility means a 
facility licensed by the NRC or an NRC Agreement State to manage 
uranium byproduct materials during and following the processing of 
uranium ores. Common names for these facilities are a conventional 
uranium mill, an in-situ leach (or recovery) facility and a heap leach 
facility or pile.
    (m) Heap Leach Pile Operational Life. The operational life of a 
heap leach pile means the time that lixiviant is first placed on the 
heap leach pile until the time of the final rinse.
0
3. Section 61.252 is revised to read as follows:

Sec.  61.252  Standard.

    (a) Conventional Impoundments.
    (1) Conventional impoundments shall be designed, constructed and 
operated to meet one of the two following management practices:
    (i) Phased disposal in lined tailings impoundments that are no more 
than 40 acres in area and shall comply with the requirements of 40 CFR 
192.32(a)(1). The owner or operator shall have no more than two 
conventional impoundments, including existing impoundments, in 
operation at any one time.
    (ii) Continuous disposal of tailings such that tailings are 
dewatered and immediately disposed with no more than 10 acres uncovered 
at any time and shall comply with the requirements of 40 CFR 
192.32(a)(1).
    (b) Non-Conventional Impoundments. Non-conventional impoundments 
shall meet the requirements of 40 CFR 192.32(a)(1). During operation 
and until final closure begins, the liquid level in the impoundment 
shall not be less than one meter.
    (c) Heap Leach Piles. Heap leach piles shall comply with the phased 
disposal management practice in 40 CFR 61.252(a)(1)(i). Heap leach 
piles shall be constructed in lined impoundments that are no more than 
40 acres in area and shall comply with the requirements of 40 CFR 
192.32(a)(1). The owner or operator shall have no more than two heap 
leach piles, including existing heap leach piles, in operation at any 
one time. The moisture content of heap leach piles shall be maintained 
at 30% or greater. The moisture content shall be determined on a daily 
basis, and performed using generally accepted geotechnical methods. The 
moisture content requirement shall apply during the heap leach pile 
operational life.

Sec.  61.253  [Removed]

0
4. Section 61.253 is removed.

Sec.  61.254  [Removed]

0
5. Section 61.254 is removed.
0
6. Section 61.255 is revised to read as follows:

Sec.  61.255  Recordkeeping requirements.

    (a) The owner or operator of any uranium recovery facility must 
maintain records that confirm that the conventional impoundment(s), 
nonconventional impoundment(s) and heap leach pile(s) at the facility 
meet the requirements in 40 CFR 192.32(a)(1). These records shall 
include, but not be limited to, the results of liner compatibility 
tests.
    (b) The owner or operator of any uranium recovery facility with 
nonconventional impoundments must maintain records that include 
measurements confirming that one meter of liquid has been maintained in 
the nonconventional impoundments at the facility.

[[Page 25412]]

    (c) The owner or operator of any heap leach facility shall maintain 
records confirming that the heap leach piles maintained at least 30% 
moisture content by weight during the heap leach pile operational life.
    (d) The records required in paragraphs (a), (b) and (c) above must 
be kept at the uranium recovery facility for the operational life of 
the facility and must be made available for inspection by the 
Administrator, or his authorized representative.

[FR Doc. 2014-09728 Filed 5-1-14; 8:45 am]
BILLING CODE 6560-50-P