### 34056 Federal Register 

## I Vol. 51, 

### No. 185 

## I Wednesday, September 24, 1986 

## I Rules and Regulations

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 61
[Ao-fR-3060-7)
National**~mission** Standards for · Hazardous Air PoHutant8 (NESHAP&); Standards for Radon-222 

### Emlsslorla From Ucenaed 

### Uranium MHI 

### TaiRnga

AGENCY: Environmental Protection Agency (EPA). · ACTION: Final rule.

SUM.MARV: This final rule establishes work practices that apply to tailings at licensed uranium mill sites. Radon-222 is emitted from these tailings in amounts sufficient to produce a risk to public health. The work practices established here will limit the emissions of'radon· 222 in accordance with Section 112 of the Clean Air Act.
EFFECTIVE DATE: The final rule is effective on September 24, 1986.
ADDRESSEES: The rulemaking record Is contained in Docket No. A-79-11. This docket is available for public uispection between 8:00a.m. and 4:00 p.m.•**~onday** through Friday, at EPA's Central Docket Section. West**Tow~r** .Lobby. Gallery

.

· One. Waterside_Mall, 401 M Street, SW., Washington, DC 20480. A reasonable fee may be charged for copying.
FOR FUJmtER INFOAMAT10H COHTACT: Terrence A. McLaughlin, Chief. Environmental Standards Branch. Criteria and Standards Division (ANR460). Office of Radiation Programs, U.S. Environmental Protection Agency, Washington, DC 20480, {Z02) 475-0010.
SUPPL£MEHTARY INFORMATION: 1

. Supporting Documents

The draft background information document and draft economic analysis issued in support of the proposed rule have been revised in response to public comments and are now issued in final form titled. respectively. "Background Information Document-Final Rule for Radon-222 Emissions from Licensed Uranium Mill Tailings" (EPA 520/1-a&- 009) and "Economic Analysis-Final Rule for Radon-222 Emissions from Licensed Uranium Mill Tailings" (EPA 520/1-86-010).

.The documents contain projections of radon emissions and the resulting risks to nearby Individuals and to populations due to the operation of the uranium milling industry, a description ofradon control technology and associated costs, and an environmel)tal and economic 

### analysis of the effects of alternative control strategies on the industry. 

### In addition. the Agency's summary of public comments on the proposed rule, together with Ute Agency's reply to these comments. are contained in the document "Response to CommentsFinal Rule for Radon-222 Emissions from Licensed Uranium Mill Tailings;, (EPA 520/1-a&-011).

· single copies of these documents may be obtained from the 

### Program Management Office (ANR -459 ), Office ofRadiation Programs. Environmental Protection Agency, Washington. DC 20460, (202) 475-8386. 

### 11. Basic Temu Used in the Notice

Defmitions ofbasic terms used in this notice are given below:

1.

### ALARA-A practice in radiation · protection that encourages radionuclide emissions to be kept "as low as reasonably achievable."

2. 

### Continuous disposal-A method of tailings management and disposal in which tailings are dewatered by mechanical methods soon after generation. The dried tailings are then placed in trenches or other disposal
areas and immediately covere d. 3. 

### Covered-Disposal of tailings in accordance with specifications required by

.regulations appearing at 40 CFR Part 192 and issued under the Uranium Mill Tailings Radiation Control Act (UMTRCA).

4. 

### Mill tailings-The waste resulting from conventional milling ofuranium
ore. Tailings are classified as either sands or slimes depending on particle size. Processing 1 ton of ore produces approximately 1 ton of tailings.

5. 

### P hased disposal-A method of tailings management and disposal that
uses a series ofsmall impoundments. Taillrigs are pumped to one impoundment until it is filled and then pumped to the next Impoundment. The filled impoundment is actively dewatered. or allowed to dry naturally. and**~en** Immediately reclaimed.

6. Radon-Radon-222; an inert radioactive gas.

1. 

### Radon decayproclucts-The seven principal radionuclides that are produced as radon-222 decays to nonradioactive lead. Radon-222 shortlived decay products means the four radionuclides with half-lives less than 20 minutes produced as radon-222 decays to lead-210

.

8

.

### Single celldisposal-A method of tailings management that

. uses a large impoundment designed to contain all tailings generated during the lifetime of the mill. At the end of the mill life the impoundment is actively dewatered or allowed to 

### dry and ls then immediately reclaimed. 9. 

### Tail/ngspile-The on-site waste impoundment in which'tailings are deposited. 

# m. Background 

### A. Industry Description

Uranium milling involves the handling oflarge quantities of ore containing uranium and its decay products. In this ore, the

. concentration of uranium and its decay products is about one thousand times greater than in otherrocks and soils. Uranium milling recovers the uranium In the ore by mechanical and chemical processes that generate waste tailings. The ore is first crushed, blended. and ground to the proper siz!! for the leaching process, which extracts uranium. Several leaching processes are used, including the use of acid. alkali. and a combination of the two. After uranium is leached from the ore. it ia concentrated from the**leach~te** through ion exchange or solvent extraction. The concentrated uranium is then extracted from the concentrating medium. · precipitated. dried. and packaged. The depleted ore. in the form of tailings, is pumped to a tailings pile 

### aa a slurry.

Since ore generally contains less than 0.5 percent uranium by weight, every ton ofore processed results in almost a ton of tailings. The tailings contain virtually aU of the uranium decay products present in the ore. including thorium-230 and radium-226. which decay to radon. Previous risk analyses have shown that radon presents the highest risk of any radionucUde released to air at uranium mills and that the tailings pile is the most significant source ofradon.

The 26 licensed uranium mills In the United States are located in Colorado, New Mexico, South Dakota, Texas. Utah. Washington. and Wyoming. In addition, four mills have been licensed but not built. The milling industry is depressed due to a decline in the demand for uranium and competition from low-coat foreign sources. Three mills are actively processing ore, 17 are on

.standby and could process ore in the future ifmarket conditions improve, and 6 are being decommissioned and will no longer process ore. The 20 licensed mills that are actively processing ore or on standby were considered in the analyses reported iri the supporting documentation. These ZO mills have about 35 tailings impoundments associated with them. Recently, three of theae mills have indica ted to the NRC that they will no longer process ore and intend to reclaim the sites.

Past milling activities have generated about 200 million tons or tailings.

. Production at conventional mills peaked

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## I Rules

. and Regulations 34057

in 

### i980. when 2l

·mllla recovered more than 17 

### thousand tons ofW'8nium and generated more 

### thaD 14

### miUion tons of tailinga. The induatry fa currently operatins at about 10

### peroent of capadty due to the depressed market At this level ofproduction. the lndu.try fa recoverins about 1.8 

### thouaarid tons of uranium and generating about 1

.4 

### million tons ofnew taillnp annually.

· At full capacity
, the industry could generate approximately 14 

### million tons oftaillilga
a year. 

### B. Estimates of Exposure andRisk Exposure estimates are based on radon emJaalons from tailings plies, since emiaalona and riakt from other parta ofa uranium mill are.amall 

### tn comparison. Radon emiaalon rate

. estimates are baaed on the radlum-2Z8 concentration In the tailings uaing the relationship of 1 

### picocurie ofradon emitted per square meter per second for each picocurie ofradium-226 per gram of tailings. II ia aasumed that the radium· 2Z8 is evenly mixed throughout the tailings and that radon is emitted from 

### all dry 

### exposed surfaces 

### of taillnp. 

### The radium-2Z8 content 

### of the taillll8S ia derived from the relationship ofonetenth ofone percent ofuranium in 

### ore equalllns 280 plcocuriea ofradium-226 per gram 

### ofore and the a11umption that all the radium·2Z8 in 

### the ore finds its way into the tailinp pile. aa appropriate. It

**I~** 

### expressed I n terms ofannual number offatal cancer cases and provides a measure ofthe overall impact on public health. For example, a total population impact of0.5 fatal

**~ncer** 

### cases per 

## year me'"'s that emiuions ofthe specific pollutant are predicted to cause one case ofcancer · every 

## zyears. As 

### distance from a source iilcreaaea, risks to specific persona

**decre~ae** 

### and become extremely emaU: but, considering the total population exposed, the sums ofthese risks may be significant.·

The two estimates together provide a better description ofthe magnitude and distribution ofrisk than either number alone. "Nearby individual riak" gi

. vea an estimate ofthe highest ris

. k, but not how many people may bear that risk. "Total population impact" describes the overall estimated health impact on tJ!e entire exposed population, but not how much riik the moat exposed persona may bear. Forexample, two sources of

· radionuclide orchemical emissions could have similar population impacta but very

. different maximum ind ividual risks. or vice versa. Both estimates are important and both are used In

### mald.ng risk 

### management decisions. The risk estimatea should not be viewed as precise determinations oflikely health damage, but rather as a general indication ofestimated health risk.

EPA's analysis ofn.ks

·due to radon Standard meteorological transport modela are 

### uaed to estlmat

. e radon

. concentrations in air at varioua _ emlsa.lons &om existing uranium tailings piles concluded:

1. 

### Lung cancer, which Ia 

### caused by the

. short-lived decay products ofradon. fa the dominant health hazard from tailings. Estimated effects ofgamma radiation and oflong-lived decay products ofradon are leas significant, although high gamma racijation distances &om the plies. Exposure to radon decay producte Ia then eatiDiated from the radon concentration In air. The final risk estimates are a .,roduct ofthe units ofradon decay product exposure levela and a risk factor that relates risk to 

### a single unit ofexposure.

Two meaaures ofhuman exposure are ofparticular"Interest: "nearby individual risk" and "total population impact".The former refers to 

### the estimated Increased lifetime risk to Individuals wlio spend their entire life at the location ofexisting residences where predicted concentrations ofthe pollutant are highest Nearby Individual risk Ia 

### expressed aa a probability: for example,
a risk ofone in

### one thousand meant that
a person spending hit lifetime at the

. point ofmaximum exposure has an estimated increasedrisk ofohe in 

### one thou1and qf developing a fatal

· cancer. Estimates ofnearby Individual risk are best e1timate1, and are not upper bound estimates. · · ·

The second measure, "total population impact", consider& people

**e~oaed** 

### at all concentrations, low as well as high, and It 

### considers people exposed throughout the United States, exposures may sometimes occur. 2. 

### Individuals living near an uncontrolled tailings pile are subject to high risks due to radon emitted from · tailings. Radon contained in th.e ambient air enters homes and other structures built near the mill through doors and .other openings In the struc ture. The resulting radon decay products tend to concentrate indoors,

. thus exposing the occupants to potentially harmful levels

. ofthe

. ae radioriuclidea. The EPA estimates that. atpresent. some persona may'beexposed to rlib 

### that are as high
as one in

### one hundred. This estimate ia baied on median risk estimates and an assumed exposure of70-years during which emission levels remain the same as present values. Ofcourse, this time period is lo1J8er than aaaunied in EPA's "40-year'' analysis. Using the 40-year analysis, an exposure poains this

. level ofrisk could only occur if an individual

. remained at that location for the full 70- year period, and the pile presenting that· risk was replaced after cloaura by another pile preaentfns tlie same risk factors.

3

. Based on models for the risk to all exposed populations (local. regional, and national), about one to five fatal
cancers per year are e$timated from emi11iona ofradon from tailings .at the 20 mill sites being considered here. if

### no controls are present. If

### the tailings at all sites were to dry 

### out, it is eafunated that the risk could rise to about two to nine fatal cancers per year. However, not aU ofthe

.piles are expected to dry 

### out at the same time. Approximately one half ofthese deaths are estimated to occur within 80 kilometers ofthe taili1J8a piles.

There Is substantial uncertainty In these eatlmatea because ofuncertainties In the emission rates ofradon from tailings sites, In the exposure people will receive from its decay products, and from Incomplete knowledge ofthe effects on people due to these

. exposures. The values presented here represent beat estimates baaed on current knowledge. Examples offactor& leadill8 to possible underestimation of risk Include: the uae

.ofmedian rather

. than upper

. bound risk factors, ignori1J8 radon sources at a mill aite other than the taillnge pile, and not considering piles where owners have Indicated

· Intent to reclaim their pile but have not

done eo for lo1J8 periods. Risks could be · overestimated if owners reclaim piles faster than EPA assumes, lfradon emissions are smaller due to leas

.. radlum-Z261n a pile than is estimated, or Ifthe radon emanation rate is lower than EPA eatj.matealt to be. 

### Additionally, s

. ince tb,eae estimates are baaed on current pile sizes and populatlbn distributions, as nearby populations increase or decrease in the future. the eatimated'impacta would · vary.lf specific information indicates radon emissions rates were lower, then risk estimates could be 19wer.

·In general, much more is known about the risks from exposure to radiation than exposure to most chemicals. While there Ia uncertainty In risk estimates from a81essmenta ofchemical emi11ions and radlonuclide emissions, there ia 

### much less uncertainty In estimates of risk from radionuclide emissions because ofthe extensive data base on theeffects ofhuman exposure to radiation

. Therefore. a risk estimate :

. resulting from exposure to radionuclides l1likely to bemore accurate than the

. aame estimate for chemical exposures. C. 

### History of StandardDevelopment The Agency's

. standards for Nuclear Power Operation (40 CFR Part 190)

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## f Rules and Regulatiqns

Issued under the Atomic Energy Ac1 (4Z 

### FR 2858 

### (January 13, 

### 1977)) limit the total individual radiation dose caused by emissions from facilities that make up the uranium fuel cycle, including licensed uranium mills. However. when 40 CFR Part t90

.was promulgated, considerable uncertainty existed about the public health Impact ofexisting levels ofradon in the air. as well as · uncertainty about the best method for management ofnew man-made sources ofradon. The EPA exempted radon from coverage under 40 CFR Part 190 since the problems associated with emission• of this radionuclide were sufficiently different from those ofother radioactive materials associated with the fuel cycle to warrant separate cons!deratlon.

EPA has

.also Issued standards ( 48

### FR 459Z6 

### (October 7, 

### 1983)) for uranium and thorium mill t ailings at commercial processing licensed sites under the Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA}
, which amwnds the Atomic Energy Act (AEA}. 

### These standards for disposal oftailings require stabilization oftailings on final disposal
so that the associated health hazards will be controlled and limited for 1000 years to the extent reasonably achievable, In any case, for at least ZOO 

### years. The standards limit releases of radon to the air after disposal, and require measures to limit releases of radionuclides and other hazardous substances to water {40CFR

### Part 192., Subparts D and E)

. In 

### the preamble to these standards

. the Agency 'diacussed the relationship between UMTRCA 

### and the Clean Air Act (CAAJ 

### and indicated its Intent to publish an Advanced Notice ofProposed Rulemaking (ANPR) 

### to consider additional control ofradon emissions during the operational phase ofmills.

Section

**~zz** 

### ofthe CAA required EPA to determine whether or not to regulate
radioactive pollutants based

·on an a1111essment ofrisb to public health. After seeking public comment (44 fR 

### 21704 (April 11 , 1979}), EPA listed airborne emissions ofradionuclidea as hazardoua air pollutants under section 112 

### or the CAA (44 FR 76738 

### (December Z7, 

### 1979]). Based on that listing, EPA subsequently promulgated standards under section 112 for Department of Energy (DOE) facilities. Nuclear Regulatory Commission (NRC) licensed facilities and non

- DOE Federal facilities, elemental phosphorus plants, and underground uranium minea (50 

### FR 5190 (February

## e. 1985 and 50 FR 15388 (April 17, 1985)}.



### On October 31, 

### 1984, EPA issued

· fts ANPR to Inform interested partie• that the Asency was considering iasuins standards under the CAA to limit radon emission• from licensed uranium mills (49 

### FR 43916 

### (October 31 , 

### 1964)). Subsequently,

**~A** 

### entered Into a stipulation with the Sierra Club to promulgate such standards, or deliat radionuclides, by May 1, 1986

. This agreement was entered as a consent order by the United Statea District Court for the Northern District ofCalifornia (Civil No

. C-34-0656 WHO)

.

On February 

### zt, 1986. EPA Issued proposed standards for radon emissions from licensed uranium mUla and · announced a public bearing (51 FR 638Z 

### (February 

### zt, 1986)). The bearing was held In Denver , Colorado, on March 25, 1986 (51 

### FR 8Z05 

### (March 10, 1986)). A transcript ofthe hearing was placed in the Docket and the comment period was extended to April 28, 

### 1986

.

Due to the complexity ofthe proposed rule and the need for an extended comment period, EPA and the Sierra Club e

. ntered into a aecond atipulation to extend the deadline to August 15, 1986. 

### The district courtgranted the extension
on motion ofthe partie

### a

. IV. Summary 

### of Proposed Standards

A. 

### noted earlier. EPA published a proposed rulemaking regarding control ofradon·ZZZ emissions from tailings piles at licensed sites on February Zt, 1986 

### (51 FR 6382)

. 

### That notice announced that EPA was considering various work practice standards for limiting such emissions based on ita preliminary conclusions that It ia not fea sible to set an emission• standard. and that the nature ofthe risk involved
warrants a regulatory response.

In 

### its proposal
, EPA presented three work practices, Including improved

. methods for disposal ofnewly gener ated tailings, various timing requirements for
use ofthese improved methods, and interim covers. The improved methods of disposal ofnewly generated tailings
were a large, single pile with immediate cloaure

. phased disposal. and continuous disposal involving dewatering and covering oftailings. EPA at.o atated It was conaidering alternatives of allowing new tailings to be added to existing pllea over a range oftimes, including 5 years, 10 years, 15 years and anundefinite period oftime

. into the future. (An 

### exception from the latter requirements was proposed where existing tailings Impoundments were lined

.)

· That proposal also discussed two

. available optiona for controlling radonZZZ emlasions from existing piles

. It concluded that earthen coven might be placed over dry 

### taillnga beache• and· embankments constructed o f sand tailings

. It 

### noted that dry beaches typically cover 60 percent ofthe total tailings area during the operational phase of a mlll and that this percentage could be significantly larger during periods ofextended shutdown. It

### also noted that use ofexisting tailings piles could be terminated. While a dry 

### out period would ensue during which emissions would unavoidably increase prior to disposal 

### .in accordance with Federal standard• under UMTRCA. this 

### Ia ao unavoidable result ofdisposal V. Summary 

### of RNJMJDHS 

### To Comment



### The Agency bas reviewed all · aubmittals to the docket and testimony

. . given at the public hearing. A complete discussion ofall substantive comments and the Agency's

**~sponse** 

### to them appears in "Response to CommentsProposed Rule for Radon-ZZ2 Emissions from Licensed Uranium Mills Tailings" (EPA

**500/1~1) ;**  

### the document may be obtained from the Program Management Office (ANR--159), 

### Office ofRadiation Programs. Environmental Protect ion Agency, Washington. 

### DC 20460

. 

### A aummary or major concerns, together with the Agency's responses. 

### are presented below. 

### Legaland

**Procedura~**



### Many commenters stated that there is
no need for regulation under the CAA 

### because existing regulat ions developed under the AEA and the UMTRCA and license conditions administered by 

### the NRC and its agreement Sta tes

.adequately protect the public from risk due to radon

.The Agency estimates the individual lifetime risk may be as high
as 1 

### in 100. 

### assuming 70 

### years of exposure

. The population risk is estimated to be 1 to 5 

### deatha peryear under current Industry and regulatory conditions

. The Agency believes that these riska are significant and that there 

### Ia a need for standards under the CAA 

### to protect public health with an ample margin of safety

.

A number of Ci>mmentera addressed ground water quallty

· and stated that it



### ·should not be considered In

### regulating radon under the CAA

. The Agency has not developed this rule to regulate ground water

. Ground water protection standard• ara currently in force and being implemented under the UMTRCA standards (40 CFR Part 192). However, potential effect• ofvarious alternatives
on ground water were considered as part ofthe analysis ofthe I mpacts ofthis rule

. since EPA has a responsibility to consider the lmpacta that Ita rules .may have onthe total environment In 

### part, this is done to ensure that regulationa do not control pollution 

### In one environmental medium only to degrade

### Federal Register 

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## I ·Rules and Regulations 34059

-another. Consequently. there may be
some additional ground water protection incidental to these standards.

Some commenters stated that EPA should not considet cost and technical feasibility ofregulation under section 112 ofthe CAA. They maintain that the Congressional mandate directs EPA to adopt standards based exclusively on protection ofpublic health. The EPA int

. erprets the requirement of section 112 to establish emission standards at a level which "provides an ample margin of safety" as not implying that these standards must ensure that therejs no remaining levtil ofrisk. Consequently; the standard being adopted today requires the use of work practices that will reduce radionuclide emissions and · therefore risks to the practical minimum. The standard reflects consideration of the magnitude of the risks, the costs and availability of further controls and associated risk reduction potential, and the potential societal impacts of regulatory alternatives. The Agency, In considering the impacts. weighe9 the estimated risks achieved by and
r emaining after application of controls and their uncertainties against the costs to achieve the emission reduction and the potential f or widespread closure

. Some commentera stated that the Agency must promulgate an emission standard to be consistent with the mill

- tailings disposal standards (40 CFR Part 192), which are·partly in the form of a design standard: an emission rate limit per square meter ofpile surface. These comments are based on a misconception of the disposal standards. The disposal· standards had multiple environmental goals including preventing misuse of tailings. reducing radon emission& for a long period oftime. and protecting ground water. The Agency determined that the best way to accomplish these goals is through the use ofa design standard based on a thicx barrier. The Agency found that a desi gn standard limiting the rate ofradon release was most appropriate given the many variables oflocation. tailings and earth characteristics. Forexample, a minimum thickness ofbarrier might not provide adequate protection under

. all conditions. The prescribed standard, which requires the release ofradon not to exceed an average of20 picocuriee

. per square meter per second, is·a design standard requiring a certain effectivenese from a cover

. The Agency stated that the standard was not to be · construed as an emission standard. "(T)he standard applies to design. · Monitoring.for radon after installation of

. an appropriately designed cover is not
required," making it analogous to· a work practice standard or design· standard authorized under section llZ(e). The Agency, thus, finds no inconsistency between the work practice standards for operations and the design standards for disposal.

The NRC questioned wby EPA did not issue an emission standard. such as already exists in NRC and State regulations, instead ofproposing a work practice standard. The Agency judges that it is not feasible to prescribe an emission standard since most of the radon emitted by a uranium mill comes from the surface of mill taUings

.piles. A typical pile·may be from a few to hundreds of acres in area, and emissions from its surface cannot be controlled phases. "During·the first six-year phase, the operator may continue to place tailings ' on existing piles. In the second· phase, this practice is terminated except for certain small piles and for those operators that make a satisfactory, individualized showing oflow interim**risk;l~.t** the third phase. without exception, tailings may only be placed in impoundments meeting size and operating limitations designed to minimize exposed area and associated radon emissions. Taken as a whole. this scheme provides protection ofpublic

. health that meets the Act's requirements · of "an ample margin of safety". 

### Technical. through a conveyance designed and Several commenters, in commenting constructed to emit or capture radon. It on the continuous disposal· method, · is also not practical to accurately and

· stated that the industry has minimal consistently measure emissions because experience with dewat ering sands and 

# or the large size of the tailings pile and ito experience with dewatering slimes. the continued modifications of the pile The Agency has found that although

· that take place during operations. For continuous disposal has never been

these and other reasons. a work practice actually practiced on uranium mill standard is being promulgated. It should tailings in the United States; it has been be noted that the NRC and State proposed by industry as the preferred regulations establish a concentration method of tailings disposal at three limit at the site.boundary in units of**sites~** These proposals were never put quantity per cubic meter ofair, but do into**pr~ctice** because of the downtum in
not directly limit the quantity orrate of uranium production. The EPA believes radon emissions. · · that these proposals. submitted by

'A commenter argued that EPA may industry, adequately demonstrate t hat not use a phased application of the work

.. continuous disposal can be a viable practice requirements. since section 112 · option. It should be noted that the of the CAA permits only a two-year method has been included

·as an compliance waiver for the installation of allowable alternative for industry, but Is technology to meet an emission not'the sole practice required for new standard. However, the two-yl,!ar piles. Itwas included t o provide compliance waiver discu

. esed by the · industry with flexibility in the commenter Is not applicable to the management of new tailings. standard adopt ed. in this rulemaking

. .Several commentera said that The Administrator has concluded that technology to dewater tailings exists, neither of the available interim work but Increased energy and manpower to practices
, wetting or'interim cover. is an accomplish this are probably not appropriate measure to 

### be imposed economically feasible. The Final generally under section tlZ. Also, is Background-Information Document and discussed in this notice. the the Economic Analysis reflect the requirements for new tailings additional costs and uncertainties In impoundments cannot be implemented dewatering tailings for the continuous 'within two years. Consequently. the disposal option. The method has been two· year period that section

. selected as a suitable work practice that 112(c)(l)(b)(ii) provides "for the an operator may choose in lieu of installation ofcontrOls" bas no meaning phased disposal.
or applicabilityhere. As a result,

·the Several commenters stated that EPA's Agency has adopted a comprehensive assumption

· or40 years of standby Is set of risk management r equirements for excessive. One commenter stated that limiting radon emissions that fall under the assumption ofa 40-year period the general category of "desigri
, bet ween the end**of~** impoundment's equipment. work practice, or operational ueefulllfe and compliance with standard[s)

..... section 112(e). These · UMTRCA requirements·**if~** reasonable. requiren:tents were designed as an The EPA judges that a 40-year standby I ntegrated program to require the period (which in practice could be · · maximum reduction of long-term cancer several different periods totaling40· incidence attributable to uranium mill years) before

· r:eclamation to Federal taUingspilee that can be reasonably standards is a "worst-case" scenario. achieved. These standards operate in The Age!icy has estiRlated the f!ltallung

### 34060 Federal Register 

## I Vol. 51, No. 185 

## I Wednesday. September 24. 1986 

## I Rules and Regulations

cancers committed under this scenario to serve as a point of reference and has 

### also evaluated a ZO.year standby period scenario. Both periods were considered when the 

### final rule was selected

.

Several commenters stated that it

.would take about &'years to design, license and construct a new tailinBS management procesa. One commenter said it could take more than 10years, and one commenter said 5 years was sufficient. The EPA agrees that, based
on the comments received from the NRC. States. and individual companies,

a 3-year period to design. license, and construct a new tailings impoundment Is unrealistically short. The Agency tudges that a period of6 years is the time needed to desigq, permit. and conatruct
a new tailings impoundment. Extensions to allow more time will be available, if due to circumstances beyond their control, mill operators are unable to complete a new impoundment within ' that period.

·Several commenters stated that more

**acc~rate** site-specific emanation factors should be used as opposed to using the relationship of 1 pCi/m1 -t per pCi 

### Ra226/g tailings. The Agency used a factor o£1 pCi/m1

### -s perpCi Ra-226/g of tailings for all dry areas and a factor of
zero for wet areas. This nme factor was used for the UMTRCA rulemaking and is the factor used by NRC. An attempt was made to develop a formula. using site specl.fic characteristics. that would provide a more precise estimate of emissions. However. the formula bas not been verified by the Agency's internal review process or by Independent experts and data on the site-specific characteristics needed to derive such estimates are not available. For these reasons, the Agency decided to continue the use of the previously accepted factor.

The NRC stated that recent literature indicates that a water cover may not be
as effective In reducing radon emissions
as previously thought. Recent technical assessments of radon emissions f.rom tailings covered with water are less than 2 percent ofemissions from dry tailings. The Agency believes that assuming no emi88iona from wet tailings a

### a compared to the more accurate 2 percent emission

. rete is an Insignificant error in the

context of this rulemaking. The Agency auumed an emission rate ofzero for all tailings covered with water or saturated with waterin estimating radon emiBBions

. Risk

A commenter stated that a sitespecific rule based on a lifetime risk of
one In a million should be set for each mill to determine the allowable exposed surface area. The EPA has not accepted the proposition that the standard must reduce risk 

### to a predefmed value, such
as a level ofone in 

### a million. The EPA believes that it must protect'the public with an ample margin of safety and that this requirement provides the Agency with flexibilit y to consider the magnitude of the risks, the practicality of measures to reduce risks, and other relevant factors. This is 

### a judgment based on many facton specific to the
source category under consideration.

Several commenters stated that radon e:qJosure from 

### mill tailings on a regional and national level is overshadowed by background radon sources. Therefore, regional and national risk estimates are meaningless. The EPA agrees that radon e:qJosures due to mill tailings, at locations distant from mill tailings sites, 

### are small compared to exposure s f rom some otherlarge sources. However, it does not follow that it is meaningless to calculate e:qJosure and risk due to emissions from such sites. These calculations are based on procedures generally regarded as sufficiently accurate to support the setting of regulatory standards. The significance of the risk isjudged based on the value ofthe individual and population risk. and the regulatory options are a88essed based on the degree

# or risk reduction and the practicality and reasonableness ofcontrol measures.

.

Many commenten stated that the significance ofeffects of radon from mill tailings on total population is negligible because there are no proven adverse health effects. The Agency agrees that the adverse health effects due to radon emissions from mill tailings piles cannot be dil"lctly measured due to the high incidence oflung cancer from other causes. However. It would be Imprudent to use this as a reason not to regulate exposure to carcinogens. The risk estimates were derived from relative risk coefficients, the use ofwhich was reco!Jlmended by the Agency's Science Advisory Board and represent current scientific knowledge

. It is EPA's position that. based on current scientific evidence, excess lung cancers result from radon emitted by tailings piles and that the projected numbers of cancen calculated in the support documents are su.{ficient to support a ·rulemaking

. Economic

Several commenteH said that the proposed rules will have significant adverse effects on industry's ability to contain costs and will threaten the industry's future. EPA's analysis shows 

### that the control me!l81.1res for new tailings disposal practices required in this rulemaking are similar in cost to alternative practices already required

.by existing regulations and. therefore. the control measures required 

### by this rule are not expected to affect the Industry'• viability. With respect to

. existing tailings. the major coat of this rule to industry is moving the timetable for final cover for existing piles forward in time because the sooner new work practices are implemented, the sooner industry must undertake the expense of reclamation. Additional costs may arise in those cases where new capacity for tailings disposal 

### will have to be created to replace the capacity lost during disposal of the existing piles. As Indicated In the Economic Analysis for this rulemaking, EPA projects that this Impact will not threaten the viability of this industry. The Agency concluded that the costs are reasonable in relation to the benefits derived and that this action is consistent with previous Agency actions

. VI

. Summary and Rationale ofF'mal Rule A. Summary

Baaed on currently available information, EPA bas determined that it is not feasible to prescribe an emission

s tandard for radon emissions from urenium mills. Radon is emitted from the surfaces oftailings piles in 

### a manner analogous to fugitive dust emissions and cannot be emitted through a conveyance deeigned and constructed to capture such radori emissions. Instead. EPA is requiring an improved work practice for the disposal ofnewly generated tailings and Is specifying a date by which all
newly generated tailings must be managed by this work practice.

EPA expects that, when tailings can no

**lo~er** be placed on an existing pile. Federal and State regulatory agencies will promptly move to require disposal of the piles to Federal standards established by the EPA and Implemented by the NRC under the AEA
as amended by UMTRCA

.

This work practicerequires that new tailings be disposed of eitherin impoundments that are no larger than

·.w acres or by the use 

### of continuous disposal in which no more than 10 acres oftailings are exposed at

. any one time. All new tailings impoundments must be designed and constructed to meet this

. work practice. Using the first alternative

would require a series of impoundments, each constructed with earthen dikes or In a excavated pit and each having a liner as required by .WCFR 192. As each Impoundment it filled
, It would be dried out and covered with earthen materials immediately

. This design permits the useFederal Register 

## I Vol. 51, 

### No. 185 

## I Wednesday; September

.24. 1986 

## I Rules and Regulations 34061

of a water cover over aU

· tailings during operations without risk ofcontaminating

. ground water. The watercover sealsin the radon. greatly reducing radon emi

.. ions to air. Also, a series of impoundments significantly reduces the amount of unreclalmed tailings at the end ofa miU'slifeUme because only one or two impoundments would still require closure

. By making final reclamation easy, the potential for larser areas ofdry tailings to remain uncovered 

### Ia avoided. and this too

. greatly reduces radon emissiona.

The second procedure
, continuous disposal
, is similarly effective. 

### Iftailings
are dewatered and immediately buried
on a continuous basis. radon emissions during the operational phase ofthe mill
are greatly reduced. At the end of the mill's lifetime, only about 10acres of tailings require·final reclamation. There is, thus, no potential for large areas of tailings to remain dry

.and uncovered as a source ofradon emissions. A liner is used to protect ground water.

At mill sites where there are existing tailings piles

. this work practice is to be phased in on a reasonable schedule

. No later than 2 years after the effective date of this rule, all owners will either certify to the Administrator that they do not Intend to build a new tailings Impoundment, or ifthey wish to build
new tailings impoundments they must apply to the Administrator for approval to construct

. Within60 days following the Administr ator's approval
, the owner must apply to the NRC for a license to construct. Following the granting of a license by NRC. construction must begin promptly and must be completed in not less than 30 months. The entire process must be completed by December 31, 1992. 

### Ifthe owner is in c:Ompliance with this schedule, new tailings can continue to be placed on existing piles until the
new impoundments are ready

. Those
owners not building new impoundments may also continue to use their existing piles until December 31 , 1992

.

An exception from the preceding schedule allowing for continued uae of
an exist ing tailings pile will be granted upon petition to the Administrator

. provided the existing pile meets one of the following conditions: (1) The existing pile is 40 acres or less and Is lined or, (2) the

· combined area ofall piles·at the site Is less than 20 acres. Each exception will last for five years, at which time the
owner may request a new exception

.

A discretionary extension for all or some of the milestones on the preceding schedule. allowing for continued uae of
an exist ing tailings pile, may be-granted upon application to the Administrator for one of the following reasons: (1) The
owner demonstrates it cannot, due to circumstances beyond its control
, complete a new Impoundment before a construction achedule milestone date or (2) the owner or operator demonstrates

. that an extension Is consistent with the CAA. To make such a demonstration, the owner must certify that the millis in compliance with applicable EP A · standards and NRC regulations and license conditione. and makes a

. submittal showing that the publi c 

### Ia protected 

### with an ample margin of safety taking into account the size and condition of the pile. riska to near by individuals

.and p· opulation.lengtb of extension requested, risk reduction practices in effect, and the expected level offuture mill activity

. An
extension may be granted for a period not to exceed 5 years, although the miU
owner will be able to apply for more than one ext ension. No exception or extension is effective after December 31, zoot and no new tailings may 

### be placed on any existing tailings pile after that date. 

### B. Opt ions CoMidered In developing 

### thia rule, EPA reviewed
a variety ofoptions in the light of comments received on Its proposal. A

. fundamental stepin this process waa tecognizing that the opportunities for regulatory response to the risks Involved
were different for existing

·tailings and for new tailings. EPA's analysis of regulatory options proceeded onthe basil ofthis recognition.

With respect to tailings that would 

### be generated in the future, EP/irecognize• that improved work practices w ere available that could Umit the period during which tailings were exposed

. prior to disposal. IJmiting thia exposure would correspondingly limit risk to health. The work practices that EPA examined reduced this exposure In

**~o** ways:_first, by placing the tailings on sites smaller than Is now the practice; second, byplacing cover on the tailings continuously or at intervals. EP A analyzed options for new tailings that varied both 88 a function of size and as a function oftime

.

With respect to tailings that already existed, EPA's ability to identify

. work practice improvements that would limit emissions was more limited

. The most direct means for reducing exposures, i.e.,
a permanent thick earth cover or water cover, could conflict with continued uae ofthe pile or exacerbate ground water problems. Measures involving interim or partial use ofearth or water covers were also evaluated

. These options are described elsewhere in this notice. Indirect means ofreducing exposures
were also explored

. These baeically involve limiting the use of the existing pile for depoeit

. lon ofnew tailings by limiting the period during which new tailings could 

### be placed on the piles. On analysis. EPA concluded that-volume restrictions would prove difficult to administer and that a more feasible approach would 

### be to limit the future
use ofexisting piles

. In the end, EPA decided that risk reductions should be reconciled with continuity of

### mill operations by phasing in the transition to new disposal methods. The best currently available information

. indicates that it will require about six years for a source to phase in new capacity

. The specific options

- considered are discussed below. Interim Cover for Existing Piles

The Agency's proposed rule contained
an alternative work practice for existing tailings piles consisting ofinterim earth
covers placed onthe sides and topJ of drytailings piles

. An Interim cover on dry tailinga acts to reduce emlasions of radon. In a wet pile. water acta to prevent radon eqllsslons so that interim
covers are not needed for the wet surfages. Upon reexamination of the int erim cover alternatives and after consideration of the comments received
on that issue, the Agency bas

. determined that such covers are not an appropriate work practice to 

### be required under this

. generally applicable rule. EPA's model of the interim cover alternative used in the analysis of the proposed rule was overly simplistic. · Sources oferror included the following factors:

1. The model did not consider tailings piles that go on and orr standby repeatedly

. In these situations, the

·interim cover is buried under new tailings followed by application of a new interim cover.

Z. The model aesumed the dry areas of the pile are covered immediately and that the pile remained on standby for an extended period of tlm

. e

. This 

### Ia unlikely, becauseregulatory agencies would
require the operator to reclaim sooner than 40 years

.

3

. Maintenance costs for interim
covers were ignored.

4. Covering high. steep slopes with 1 meter of earth is a difficult engineering feat and may be mora expensiveand impractical than the model assumed it to

. be
, and in practice may endanger

workers.



## s. Slimes may underlie taUings considered to be dry
, making such tailings uncoverable because heavy equipment necessary to apply the cover would sink into the pile

. 

### Ifdry tailings cannot 

### be covered, this would reduce benefits.

### 34062 Federal Register 

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, No

. 185 

## I Wednesday, September 24, 1986 

## I Rules and Regulations

The Final Background Information Document and Economic Asseasment containe a 

### rnited model that attempts to account for these factors. The Agency now believes that interim cover is inappropriate 

### as a generally applicable work practice.

The appropriateness ofinterim cover can only be evaluated on a site-by-site basis. Though ita uae In some cases would be practicable and could lead to significant risk reduction, in 

### othen it 

### would have dubioue riak reduction

. benefits, coets that appear unwarranted as one oftwo alternative workpractices required by the final rule because it 

### reducea health riaka due to radon f rom t aUings
, providing public health protection with an ample margin of safety during the operatmslifetlme ofa uranium mill tailings impoundment. 

### In this disposal scheme
, a aeries ofsmall Impoundments Ia con1tructed over the lifetime of a mill. 

### Each small impoundment would be consttucted with earthen dikes or in an excavated pit and, under existing Federal regulations

. muat be lined to prevent ground watercontamination. After each impoundment

.fills, it will be dried out and covered with earth as soon as practical. Disposal costs will be

· spread over the operating life ofthe mill. The in relation to thoee benefits
, and would present hazarda to the eafety ofworkera. Moreover, enforcement ofa requirement for Interim covers would be difficult and controversial because it would not 

### be obvious which parts ofthe pile are dry e nough to eover and whether future operational plana are firm enough &0 

### that it ie reasonable to delay application of an Interim cover

. · design permits the use of a water cover over moat ofthe taUings, with only a small risk ofcontaminating ground water

. The Agency believes that in establishing generally applicable standards it should seek permanent solutions rather than temporary ones. I nterim earth covers are temporary because they are often covered by new tailings when the m!U retuma to · operation. The new tailings on top ofthe · interim cover release radon. removing the beneficial effect ofthe cover

. The value of

### the Interim earth cover is also lost when the final cover required by Federal Regulations le put In place. Final reclamation normally requires piles with steep sand dams to be recontoured to a more etable shape. Any interim cover would be 

### lost due to 

### mixln8 with the tailings during the recont ouring. A better use for the limited reaources available to the producers ofuranium would be

### final disposal consistent with federal standards.

The State ofNew Mexico expressed concern about severe additional environmental impactt due to the 

### diaruption ofmany additional acres of land to obtain cover material.The NRC raised serious safety concerns f or interim coven

. The NRC stated that interim coven on dams would interfere with Important safety practices. such as movement monitors for tailin8s dams. They also stated that covering of certain drain 

### portions ofthe dams could seriously reduce their stability.

·.

In 1ummary,

### the Agency concluded that requiring operators ofexisting tailings piles to immediately add and maintain interim earth covers on all dry 

### surfaces ia not an appropriate generally applicable work practice

. Phased Disposal

The Agency is eelecting phased · disposal for new tailings impoundments An important benefit ofphased disposal is that iteliminates the difficulties and expense ofreclaiming large tailings piles at the end ofthe impoundment life. By limiting the size of the piles, very large areas oftailings are prevented from becoming 

### expoeed to air
, drying 

### out. and emitting radon during extended standby periods

. At the end ofthe mill's lif etime, only one or two impoundments will still require reclamation.

These characteristics ofphased disposal combine to reduce radon emissions. The liner under the tailings pile helps maintain wetness o f the tailings by preventins water from leaching into the sround

. This 

### not only protects sround water

. but also greatly reduces radon emissions by keepins the tailings wetExperience with phased disposal shows that the tailings often stay so wet that water must be pumped out ofthe impoundments.

Since control ofradon emissions is achieved by keeping the tailings 

### saturated or covered with water, it 

### Ia important that impoundment liners have water retention capability

. In 

### most cases eligible for thia exception, impermeable synthetic liners will be required. However, UMTRCA standards (40 

### CFR

. Part 192) 

### allow an exception from the synthetic liner requirement ifit 

### is demonstrated that ground water contamination will not occur.

The size ofthe pile also helps reduce emisaions. It 

### doee so by reducing the time for the dry 

### out and standby period& that precede final cloeure, when radon emissions are at their highest. Since the piles are smaller
, they dry 

### sooner, and the expoeed surface area ia reduced

. Closure Ia relatively easy and ine xpensive, reducins the incentive for the owner to delay disposal

. To further reduce the time before closure, this rule allows a company to operate a maximum oftwo tailings Impoundments
at once

. Companies can legitimately need two operating piles to work most efficiently-(especially when one pile is almost full), but by limiting an owner to only two operating plies. an owner must close ita first pile before it opens ita third pile (or close ita second before it 

### opens the fourth. etc.). This incentive will work to reduce etandby periods

.

Phased disposal, therefore. is a tailings management system in which

· tailings are kept wet until they are dried

and disposed

. Radon emissions are reduced while the pile Ia in uae and while the pile is on standby. This results In a large reduction ofthe total emissions from mill tailings pile and, therefore, protects public health with an ample margin of safety.

Constructing, filling. and reclaiming tailings impoundments in series coet s Jess than using a single. large impoundment when a reasonable (5!11i) discount rate is used. This lower cost reflects the lower Initial capital expenditures for phased disposal. Further coat savings may be 

### realized in phased disposal by using excavated earth from future 

### impoundments to reclaim filled, dry impoundments

.

Phased disposal is the best available demonstrated technology for uranium mill tailings management. The two mills most recently licensed by the Nuclear Regulatory Commisaion use phased disposal designs

.

The Agency also considered a 20-acre li

mit for each phaaed disposal impoundment in

### the proposal (51 

### FR 6382)

. One commenter found a 20-acre limit acceptable but stressed the need for economic assessment of size limita. Several commentera argued that the Agency should allow flexibility for sitespecific considerations and should not dictate a specific limitation. The Agency evaluated both 20- 

### and 40-acre phased disposal options

. It 

### found that the 40- acre impoundment provides about the same health protection as the 20-acre impoundment, but at a slightly lower cost. The Agency concludes that a 40- acre ' size limit for phased disposal protects health with an ample margin of safety, as required by section 11Z. The 40-acre impoundment is the maximum size allowed under the rule; an operator can choose to build a smaller one.

The 40-acre phased disposal work practice

.provldas considerable flexibility for

**constructio~** 

### and operation oftailings impoundments
, although all existing rules (includins 

### 10 CFR Part 40 and 40 

### CFR Part 192) 

### muet still be f ollowed. For example
, under this work

### Federal Register 

## I Vol. 51, No. 185 

## I Wednesday, September 24, 1986 

## I Rules and Regulations 34063

practice. impoundments can be constructed in hollow• by building a dam acroea the hollow and storing the tailings on the upstream side. The standard only limita the total area of any impoundment used for storage of uranium mill tailings; other lite-specific design considerations are not affected.

Liners are required at all new uranium tailings impoundments under existing rules (40 CFR Part 192). The tradeoff& between potential problema and the advantages ofliners were considered in that previoua

. rulemaking (48 FR 45926). Continuoua Disposal

The Agency selected continuous disposal as an alternative work practice under the final rule because It reduces health risks from radon from tailings to the same extent as phased disposal and provides quick reclamation of the sUe. This disposal method calls for tailings to be dewatered as they are generated. placed in pits or on pads, and covered with about 3 meters of earthen materials
on a continuoua baais. Disposal pita or pads would be constructed with impermeable liners

. This method would rely on a thick earth cover to reduce radon emissions rather than on water 

### as in the phased method disposal During operation. no more than tO acrea of tailings could be uncovered at any given time. To aBBure that the water remaining in the tailings after dewatering (wblch Ia
never completely effective) and rain water does not seep 

### throiJ8h the tailings and contaminate ground water. a continuoua disposal impoundment is lined in accordance with 40 CFR 192.3Z. The potential for ground water contamination is nesllglble.

A second Important benefit of continuous disposal is that It would eliminate the difficulties ofreclaiming large tailings piles at the end ofthe impoundment life. 

### By requiring disposal of tailings u they are generated, very large areas of tailings are prevented from 

### beins exposed to air, drying out. and emitting radon during extended standby periods.

The technology of continuous disposal has not been demonstrated for uranium mill tailingS in the United States. However

. the induatry hae proposed this method for 

### use at three aitee. 

### The decline in uranium demand is one of the major reasons why none ofthese proposals wae put into practice. Tail.i.ngs dewaterlns systems have been used successfully at nonfenous ore beneficiation mille. The Agency believe• that these proposals and experience• demonetrate that continuous diapo&al
can be a viable work practice.



### Flexibility ia provided to allow designs that can take advantage of site- . specific characteristics. For example. there is no requirement that tailings be disposed ofbelow surface level and no restrictions that limit the use of topographical features ofa site as tailings dams. However, aU existing regulations still apply;

Although the industry commented that continuoua disposal ie not practical. thie is not a

**persua~ve** argument, since at least three companiea have cho sen this method as their-preferred disposal method in detailed sit e design plana and applications. Also, as noted above, dewatering tailiilgs has been performed in other extraction industries. The Agencydecided to allow the industry to select either continuoua or phased

. disposal because both methods provide similar levels ofradon reduction and either method could be preferable to the other. depending on the specific physical, environmental. or economic conditions that exist at the site. 

### C. Existing Piles

The regulation of uranium mill tailings disposal piles requirea different approaches to new and existing taUinp impoundments. 

### From the standpoint of · risk reduction. new impoundments 

### can readily be designed and operated in · order to achieve substantial reduction of risk at a reasonable cosl EPA. thua

. haa adopted atandarda that have the effect oflimiting the total exposed surface area during the active phase of an impoundment's existence. Exis ting impoundments present more difficult regulatory problems. They were constructed over a 

### thirtY. year period. range in size from a few acres to several hundred acres. and are located in different areas

## with di!ferent topography, soil charac

. terlstics
, tailings characteristics, and other factors affecting health risks. Consequently, they are not auaceptible to a single regulatory scheme ofthe sort adopted here for new impoundments. 

### In addition.

.the NRC 

### and their agreement States resulate practices at these sites on a site-by-site basis. For example
, the NRC baa stated Incomments that it typically requires interim cover for the purpose of dus t control on appropriate portions of existing piles.

EPA investigated work practices that might be imposed generally upon existing tailings piles that would reduce risks until they are closed and raplaced with new piles. Aa discuBBed previously. the Agency found that the two principal options, wetting and interim cover,

· made no sense to impose as acrose-the· board requirements. While Interim cover has theoreticalappUcabillty. Its risk 

### reduction is not great in many situations, and coats are disproportionate to that limited reduction ofrisk. Wetting. particularly in unlined impoundments 

### in arid areaa
or the Southweit, yields some risk reduction but again at a disproportionate cost. Moreover, wetting at unlined impoundments can lead to ground water contamination. exacerbating a problem that several

. operators are now trying to
· remedy. EPA believe• that the reasonable
course to deal with these impoundments • is to adopt requirements that will encourage their closure, in the long tenn. in accordance with requirements setby EPA and the NRC. At the same time, these requirements must be tempered with flexibility for the particular circumstances ofindividual impoundments. It 

### ia reasonable to do this in light of the wide disparity 

### in risk from different existing impoundments. and the small number of those impoundments. ·

Accordingly, the

**~I** rule senerally requires the cessation ofdisposal of tailings at existing impoundments six yean after promulgation ofthese resulations

. The requirement for cessation of disposal 

### will remove any obstacle for the NRC 

### or an agreement state to require. after an appropriate dry out period, fmal closure of the Impoundment. since it can no longer be used for disposal ofnewly generated ' tailings. In EPA's view
, the risk that 

### will

result from thia phase in period of continued disposal at exiating impoundments is consistent with the protection ofpublic health with an

.ample mal'8in ofsafety. Exception for Existing Lined Impoundments

The Agency bas determined that certain existing tailings management

·impoundments presently meet the requirements of the new work practice standards. Therefore, the Agency is providing an exception from the schedule requirements. which are specified below, for impoundment designs that are no larger than 40acres and have 

### a liner meeting the specifications of40 CFR 192.32. This requirement assures that the impoundment has the capability to retain water, thereby keeping tailings wet and greatly reducing radon emissions

. Exception for Small Tailinp Piles

The Agency,ln its examination 

### of the uranium milling induatry, has discovered that each mUlls unique and that 

### not all mills present 

### a significant health risk to 

### the public. The Agency found that one of the most impo"ant mill characteristics

### · 34064 Federal Resister 

## I Vol. 51, No. 185 

## I Wednesday, September 24, 1986 

## I Rules and Regulations

that affect risk Ia the size ofthe 

### mill tailings pile. The Agency also found that milia having combined pile 

### areas smaller than 20 

### acres have very small · radon emissions. The A8ency belie

. vea that such a mill doea not threaten pubUc

. health

.Therefore, the Agency has 

### decided to except them from the 6-year schedule. Such an exception is consistent with protection ofpublic health with an ample margin ofsafety. D. Schedule

### for Standards Implementation



### The Agency Ia requiring that all tailings generated at existing millaitea after December 31, 1992, be managed by one ofthe work practices specified in the final rule. By phasing out existing tailings piles and requiring new tailings generated at existing mill sites tobe placed in impoundments subfect to the new work practice, risks to individuals and populations are. reduced and the public ia protected with an ample margin ofsafety

. The Agency Ia assuming that. when tailings can no longer be placed on existing piles, Federal and State regulatory agencies will promptly move to require reclamation ofthe piles to Federal standards establiabed under the

· AEA 

### through UMTRCA

.



### The Agency i8 

### aware that section 112 

### baa provided for only 

### a 2-year compliance waiver. However, it l:a· 

### Impossible to design. license, and build a new tailings impoundment in that short period oftime. The operaton of existing mills are given the time necessary to install new impoundments. To aSBure that new tailings impoundments are

### built and used 

### as soon as practical, the Agency has established a strict schedule witb milestones for meeting regulatory requirements and construction ofthe facility. Industry Ia provided with sufficient time to prepare new impoundments while, simultaneously, there is a strict timetable that must 

### be met. This timetable is designed to be flexible to assure that iftime is saved in one part ofthe procesa tlie impoundment will be ready sooner. The rule also provides an extension mechanism to give operators a chance to have more time if, 

### due to circumstances beyond their control, they are unable to meet the schedule

.

The Agency haa examined the effect from the continued use ofexisting piles during the 8 

### years required for the construction of new tailings impoundments

. In 

### performing the analyaia ofthe effect of allowing all 

### mills to operate for 8 years, relevant radon emissions come only from some ofthe mills. Since EPA's original analysis, 3 ofthe ZO mills have alated an Intent to go to closure and. therefore, are 

### not effected by 

### this standard. The resulting risk from radon emissions in 

### allowing all other mill• to operate for 6 

### years is

### not significant. The uae orthese mills for this short time period represents a marginal risk that does not justify the economic waste ofrequiring a mill owner to build an Impoundment that the owner has no intention ofusing. Because bf 

### these low risks, 

### operators of exiating pilee who want to continue to uae their existing piles may do so f or the

**~year** 

### period.

Any owner or operator of 

### a licensed uranium mill who wishes to continue to use existing tailings impoundments must submit an application to the Administrator for approval to construct 8 

### new impoundment or certify that they do not intend to build 8 

### new impoundment. Thia should be 

### done as soon

.as possible, b'ut no later than Z 

### years after the effective date of

### this rule. This period'ls necesaary to provide the time needed for owners to decide whether or not to build a new Impoundment and. Ifthey decide to build a new Impoundment, it 

### also provides the time needed for the purchase of a site
, for the collection of site data and for the design and

. preparation oflicensing material for 

### EPA and NRC. Owners not building new Impoundments may continue to use their existing pilee until December 31, 

### 1992.

The Agency anticipates an Internal review and decision period following submittal ofa complete application. After the Agency's approval to conatruct. the owner or operator must apply to the NRC within 60 

### days for a license to conatruct a new tailing&

. impoundment under 10 CFR 40. 

### The Agency anticipates that NRC will act promptly on the application. Following the receipt of a license from the NRC. the owner or operator must then start construction ofan impoundment within 90 

### days, weather permitting, and must complete construction within 30 

### months.

The Agency proposed alternative schedules ofimmediate, 10

### years, 15 years, and no time limit for mandatory use of work practice standards. Comments from the NRC and the industry agreed that new impoundments probably could bebuilt in 6 

### y ears. Although one industry commenter estimated that it

### would take more than 10 years to finish new impoundments, in general. the record did not support a 

### toyear option. E. Schedule Extension



### The Agency recognizes that 

### strict adherence to the achedule may not always bepossible orreasonable. The Agency may grant an extenaion for any · schedule milestone for certain reasons.



### The first reason for the extension Is 

### practicality. The Agency is allowing mill owners 6 

### years to build new lmpoun«;imenta, because it ia 

### the Agency's estimate
, aupported bythe record, that 6 

### years Ia normally a sufficient time to design, license and build a new uranium mill tailings Impoundment. But the Agency recognizes that, due to circumstances beyond the 

### mill owner's control, situations can arise that delay

. completion. In these situations, the mill owner can apply for a schedule extension to provide him with sufficient time to complete the new impoundment.

There ere other reasons why an extension may be required. For example,
as previously noted. each mill is unique and individual milia may present amall risks to public health

. To take care of any ofthese situations. the Agency may grant 

### an extension, provided tbat the 

### mill owner can demonstrate that the extension, under conditions existing at the thne ofthe request, Is consistent with protection ofpublic health with an ample mafgin of safety as specified in 

### t 61.2SZ(e}. This extension may be granted for any schedule milestone. For example. the Agency expects that extensions would be 

### granted £or mills with moderately sized piles and that have no people living nearby. Such 

### mills · present small riska to maximally exposed individuals and small risks to regional and national populations. The Agency may grant an extension, conditionally if

### required. only upon finding that thla extension

**p~tec**

**ts** 

### public health with an ample margin of · safety.

The Agency may grant these extensions based on an examination of factors relating to the overall remaining health risk. including the size, condition, and location ofthe pile. the length of extension

**re~ueated**

**,** 

### the expected level offuture activity, and any risk reduction practices the mill owner has undertaken
or pledges to undertake. 

### VII. Implementation ofthe Final Rule

Operatorll ofnew tailings impoundment• constructed after the promulgation date of thla rule must apply to the Administrator ofEPA for approval to 

### construct a 

### new Impoundment pursuant to aection 61.07 ofthe Clean Air Act.

Operators ofexisting tailings impoundment should follow the implementation'plan detailed in 

### I 81

.252 

### (b) or (c)

. Ifthe Administrator finds
, on the baals ofany available information that there is a violation of any

### Federal 

### Register 

## I Vol. 

### 51, No. 185 

## I Wednesday,

.September 24, 1986 

## I Rules and Regulations 34065

requirement of an applicable implementation plan
, the Administrator will enforce with remedies described in section 113 

### ofthe Acl

Operators ofexisting tailings pileS who wish an exception listed In § 61

.252(d) from the schedules listed in § 61.252 (b) or (c) in order to continue to use 

### a pile should write to the · Administrator, providing the reason why the exception I s warranted

. The

. Administrator will grant. grant with conditions. or deny the exception. If granted. the owner must reapply to EPA every 5 years that It still meets the criteria for exception. 

### Ifat anytime neither of the exceptions criteria apply, the owner must notify the Agency and immediately ceas&""use ofthe pile.

Operators ofexisting tailings piles who wish extensions from the schedule milestones listed in§ 61.252 {b) or {c) in order to continue to use an existing tailings pile should write to the Administrator providing the reasons why an extension should be granted, taking care to provide the infonnation requested in § 61.252(e). This must be · done at least 1 year before the milestone date for which the extension is requested. The Administrator will grant, grant with conditions, or deny the extension within 9 months

. Although multiple extensions may be granted. each extension will last no more than 5 years.

All requests should be sent to the Assistant Administrator for Air and Radiation (ANR-443), U.S. Environmental Protection Agency, 401 M Street, Washington, DC 20460.

No exception or extension will be effective after December 31, 2001. This deadline allows owners ofexisting tailings impoundments a chance to use those impoundments in those cases where to do so would not endanger public health. while assuring that the system of exceptions and extensions will not be subjectto any potential abuse by mill owners. Inthis way, the rule will cause even greater reduction in radon emissions as phased or**continu~us** disposal methods are implemented.

Nothing In this rule is Intended to affect the existing regulatory authority of the NRC. EPA hopes that it will be able to reach an agreement with NRC to allowNRC to take an important role in the implementation and enforcement of this rule. This would allow EPA to take full advantage ofNRC's expertise in this field and help minimize the duplication ofeffort and conserve administrative
resources in accord with § 12

. 2 of the Clean Air Act

. 

## vm

.Miscellaneous .A. 

### Docket The docket is an organi:ed and complete file of all inf onnation considered by EPA fn·the development of this proposed standard. The docket allows interested persona to identify and locate documents so they can participate effectively in the rulemaking process. It also serves as the record for judicial review.

Transcripts ofthe hearings, all written statements, the Agency's response to comments, and other relevant documents are placed in the docket and · are available for l.napection and copying during nonnal working hours. 

### B. Executive Order1.2291

Under Executive Order 12Z91
, issued February 11, 1981, EPA must judge
, whether 

### a rule 

### is a "majorrule" and
, therefore, subject to the requirement of a Regulatory Impact Analysis. The EPA has determined that this rule is not a major rule as defined In section l (b) of the Executive Orderbecause the annual effect of the rule on the

· economy will be less than $100 million per year. Also, it will not cause a major increase in costs or prices for any geographic region

. Further, it will not result in any significant adverse effects on competition. employment, investment, productivity, innovation. or the ability of the United States enterprises 

### to compete with foreign enterprises in domestic or foreign markets. Under Executive Order 12291, this rule was submitted to the Office ofManagement and Budget (OMS) for review. Any comments from OMB to EPA and any response to

. those comments are included In the docket. C. 

### Paperwork Reduction Act

The fmal rule does not impose any reporting or recordkeeplng requirements
on operators ofuranium mills and associated tailings piles. D. RegulatoryFlexibilityAnalysis

Section·eoa of the Regulatory Flexibility Act, 5 U

.S.C. 603, requires EPA to prepare and make available for comment an "initial regulatory

. flexibility analysis" in connection with

. any rulemaking for which there is a statutory requirement that a general notice or proposed rulemaking be published.

However, section 604(b) of the

. Regulatory Flexibility Act provides that section 603 "shall not apply to any

. proposed

. . . rule ifthe

· head of the Agency certifies that the rule will not. if promulgated have a significant economic impact on a substantial number of small entities." The EPA believes this final rule will have little or no'impact on small business

· because the total costs associated with the standards will have relatively little impact on the total cost ofproducing uranium oxide.

For the preceding reasons. I certify that this rule will not have a significant economic impact on a substantial number ofsmall entities. 

### E

. GeneralProvisions The general provisions of40 CFR Part 61, Subpart A apply to 

### all sources regulated by this rule, except as otherwise noted.
F. 

### StateImplementation and Enforcementof Emission Standards

.Under section 112(d)(1) of the CAA. any State may develop and submit to the Administrator a procedure for implementing and enforcing emission standards for hazardous air pollutants for stationary sources located in such State. 

### Ifthe Administrator finds a · State'sprocedure for implementing the standard is adequate
, the Federal authority then is delegated to the State. To streamline this procedure
, some of EPA's Regional officas have entered into agreements with certain States for "automatic" delegation ofnew section 112 standards. Under this arrangement, States are delegated authority to implement

.and enforce all new section 112 standards when they are Issued.

The Agency has decided that "automatic" delegation shall not be made for the radionuclide NESHAPa. When EPA entered into these agreements, the State's capabilities and expertise with respect to radionuclides
were not considered. Therefore, States must reapply for delegation in the case ofradionuclide NESHAPs. 

### G. Relationship to 

### OtherPrograms

It

### Ia important 

### to note that EPA has authority to regulate QJining wastes

. under the Resource Conservation and Recovery Act (RCRA). aa well as the CAA and UMI'RCA: Since the**consld~rations** under each statute may vary, the regulatory program for uranium mill tailings under the CAA and UMTRCA might well differ from the program EPA intends to develop for mining waste under RCRA. The RCRA program will be tailored to the risks associated with mining wastes and the technical feasibility of various control

. options (see 51 FR 24496: July 3, 1986).

H. 

### Communications

Communications with the Administrator regarding the reporting and recordkeeplng requirements ofthis ·'

### 34066 Federal Register 

## I Vol. 51, No. 185 

## I Wednesday, September· 

### 24, 1986 

## I Rules and Regulations

rule, as well as requests for

-waivers, shall follow the provisions ofPart 61.10, except as otherwise noted 

### in this 

### rule.

This rule is effective immediately for
new sources and existing facilities. Those facilities that are not in compliance with the final rule based on infonnation currently available to them, may request a compliance waiverfrom the Administrator under the provisions ofsection 112(c)(t). List of SubjectS in40 CFR Put 81



### Air pollution control, Hazardous materials, Asbestos, Beryllium, Mercury, Vinyl chloride, Benzene, ArseniC: and Radionuclides.

Dated: AIJ8Ual 15, 1986. Lee M. Tbomu, Administrator.
PART 61-(AMENDEDJ

Part 61 

### ofChapter 1 

### of

. Title 40 

### ofthe Code ofFederal Regulations Ia 

### amended
as follows:

t.

### The authority citation for Part 61 continues to read as follows:

Authority: Secll. 112 and 301(a) Clean Air :Act, aa amended [42 U.S.C.7412 (a});



### 2. By 

### adding a new Subpart W 

### to read as follows: · SUbpartW-NaltonllErn18a1on Standanl for Radon-222 Emlselona From Ucensed

. Unmlum Mil Tdlnp

Sec. 61.Z50 Applicability. 61.251 Definitions. 61.2.5Z Standard. SUbpartW-Natlonat Emlaalort Standard for Radon-222 

### Emf88lon8 From 

### Ucensecl Uranium 

### MUI Tailings

t t1.260**~.**



### This subpart applies to licensed sites that manage uranium byproduct materials during and following the 

### processing ofuranium ores, commonly referred to as uranium mllla and their asaoclated tailings. Thla subpart applies during the period ofoperation. · · 161.261 Deftnltlons.



### As used in this subpart, all terms not defined here shall have the mea.nins given them in the Clean**~r** 

### Act or Subpart A ofPart 61. The following tenus shall have the following specific meanings:

(a) "Area'' means the area covered by the.vertical projection ofthe pile upon the earth's surface.

(b) "Commission" means the Nuclear Regulatory Commission orits Agreement Statea (where applicable).

(c) 

### "Continuous disposal" means a 

### method oftalllngs management and disposal in which tailings are dewatered by mechanical methods immediately after generation. The dried tailings are then placed in trenches or other disposal
areas and Immediately covered to Federal standards.

(d) "Covered" means to cover with earth sufficient to meet Federal standards for the management of uranium byproduct materials pursuant to 40 

### CFR 

### 192.32.

(e) 

### "Dewatered" means to remove the water from recently**produce~** 

### tailings by 

### mechanicel or evaporative methods such that the water content of the tailings does not exceed 30 

### percent by weight.

(f) 

### "Existing tailings pile" means a tailings pile that is in operation on the effective date ofthis rule. ·

(g) 

### "Ucensed site" means the area contained within the boundary ofa locetion under the control ofpersons generating or storing uranium byproduct materials under 

### a li

. c ense issued by the Commission. This includes such areas licensed by Agreement States, i.e., those States which have entered into an effective agreement under Section 274(b) ofthe Atomic Energy Act of 1954, as amended.

(h) 

### "New tailings" means uranium tailings produced**~fter** 

### the effective date ofthis rule. ·

(i)

### ·"New tailings impoundment"
means any location or struc ture at which uranium mill taillngs are temporarily or permanently stored and which Is placed in operation after the promulgation ofthis rule.



# m "Operation" means that an 

### impoundment Is being used for the continued placement ofnew tailings or Ia in 

### standby. An 

### impoundment ia In

. 

### operation from the day that tailings are first placed In 

### the impoundment until the day that final cloaure begins

.

(k) 

### "Owner" means any person who
owns oroperate& a uranium**~II** 

### or an exi8tlng tailings pile or a new impoundment.

(1) 

### "Phased disposal" means a method oftailings management and disposal which uses lined impoundments meeting the requirements of40 

### CFR Part 

### 192.32,
no greater than 40 

### acres In 

### area, wJlich immediately filled, upon becoming dried. and covered to Federal standards.

(m) "Uranium byproduct material" or "tailings" means the wastes produced by the extraction or concentration of uranium from any ore processed primarily for its source material content. Ore bodies depleted by uranium solution extractions and which remain 

### unde11round do not conatitute byproduct material for the purposes of this subpart. §61.252 Standard. 

### (a) All new tailings·impoundments 

### built after the effective date ofthis rule shall be designed and constructed to meet one ofthe two following work practice standards and in the following

. manner:

(1) 

### Phased disposal in lined tailings impoundme

. nts that are 

### no more than 40 

### acres in area and meet the requirements of40 CPR 

### 192.32(a). The owner shall have no more than two 

### impoundments in operation at any one site at any one time.

. ·

(2) Continuous disposal oftailings such that the tailings a

. re dewatered and immediately disposed with no more than 10

### acres oftailings being uncovered at any time and operated in accordance with 40 CFR 

### 192.32{a).

(b) 

### Owners who build new tailings impoundments may continue to place
new tailings or waste water associated with milling or mining activities on existing tailings piles only until new tailing& impoundments are constructed. and only if

### the owner is In 

### the process of designing, licensing. and constructing
new tailings impoundments in accordance with the following schedule:

(1) As 

### soon as practical. but no later than 2years after the effective date of this rule, all owners who wish to build
new taiUngs impoundments shall apply to the Administrator for approval to construct under section 61.07. 

### The Administrator shall make a determination to grerit or deny any application for approval in 

### accordance with section 6t.OS. 

### except that the time limitations of subsections (a) and (d) shall not apply.

·(2) Within 60 

### days following the Administrator's approval to**con~Jtruct** 

### a 

### new tailinga Impoundment. the owner shall apply to the Commission for a license to construct a new tailings Impoundment.

(S) 

### Following the granting ofa 

### license by the Commission, the owner shall begin 

### construction ofthe new tailings Impoundment within 90 

### days unless seasonal conditions do not permit, In which cese construction shall begin at the start ofthe next construction season. This impoundment shall be completed and shall be ready to receive new

. tailings within 30 months ofthe date of licensing by the Commission.

(4) In 

### no event shall new tailings be placed on existing taUings piles after December 31, 1992, unless the owner has received anexception orextension from the Administrator In accordance with paragraphs (d) or (e) ofthis section.



### (c) Owners who do not Intend to build
a new tailings impoundment must certify

. to the Administrator as soon as ·

### Federa l Register 

## I Vol. 51

. No. 185 

## I Wednesday. September 24, ·1986 

## .f Rules and Regulations 34067

possible. but no later than 2 years such time as neither of the two criteria following the effective date of this nile. continue to apply. the owner shall so that they do not intend to build a new notify the Administrator, and the impoundment at the mill site. Owners · exception shall terminate. who make this certification will be able

. (e) An 

### owner may · apply to the to use their existing·tailings piles for the Administrator on an impoundment-bydeposition of new tailings or waste impoundment basis. for a.n extension to water associated with milling and continue using an existing tailings pile

. mining activities until December 31. {1}{1) An 

### extension may be granted 1992. unless they receive an exception or upon a showing that; despite a good extension from the Administrator in faith effort by the owner. it cannot. due accordance with paragraph (d) or (e) of to circumstances beyond Its control. this section. in which case the owner. meet any paragraph (b) 

### schedu.le may continue to use the existing tailings deadline. piles as permitted by t he terms of the · (ii) An 

### extension may be granted, for exception or extension. · any paragraph (b) or (c) schedule

(d) An 

### exception for continued use of deadline at the Administrator's
an existing tailings pile shall be granted discretion. upon a showing by the owner upon application for approval to the that the

· extension is consistent with · Administrator provided that: protection of the public health with an

(1) 

### The existing tailings pile is 40 ample margin of safety. To make this
acres or smaller in area and meets t he · showing, the owner must first certify requirements of40 CFR 192.32{a)(1), or that" it is in compliance with applicable

(2) 

### The combined area ofall piles at a existing NRC regulations and license licensed site Is less than 20 acres. conditions. In addition, the The Administrator will grant. grant with Administrator will also take into conditions, or deny the application. lf 

### account: the size and condition of the granted, the owner mu!lt certify to the pile
, the size**a~d** 

### location of the nearby Administrator every Syears that it still population. the length ofextension meets at least one of the preceding requested, the existence and criteria. Following

.this certification, the effectiveness of any risk reduction Administrator will grant, grant with practices that are or will be taken, and conditions or deny the exception. At any the expected level offuture mill activity. (2) The owner may apply for an extension at any time up to I year before the cease-use date. The Administrator will have 9 months from the date of

· application to grant. grant with

conditions or deny the extension: Subject to paragraph {g) 

### of this section.
no extension will be granted for longer than 5 .years, and no extension pursuant

· to paragraph {e)(l)(i) shaltbe granted for

any period longer than necessary for the
owner to meet applicable paragraph (b) 

### requirementi.

{3) The owner may apply for as many extensions·as needed. Each extension must be applied for and proven separately.

(4) 

### The Administrator will provide for public notice and comment on all applications for approval of extensions.

(f) 

### All applications for approval of exceptions or extensions shall be sent to the Assistant Administrator for Air and Radiation {ANR-443), U.S. Environmental Protection Agency, 401 M Street
, SW., Washington.. DC 20460.

(g) New tailings shall not beplaced on any existing tailings pile after December 31, 2001, and no·exception or extension
shall be effective after that date.

·[FR Doc. 88-20193 Filed 9-23-88; 8:45 am} IILLIHO**COD£~**