OCCURENCE AND AVAILABILITY OF HELIUM IN THE USSR (RR MP-238)

Created: 6/27/1985

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69

XVURREHOS pjtT. AVAMABtLlVt HEM IN iH THE trSSK

CM HISTORICAL REVIEWRELEASE AS SANITIZED

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IBIS MAIER'AI.iNrVpMATICMi; THE NATIONALOF IUETES WITH IJ TflKAWS,, SETS Wi, IHE IRANSMISS'.OB OPF WHirBANYH :JNA</TB0F'ZET PERSON IS

CivMTKAI, IMTKfXtGrJiCE AOEKCy

In7 Uic Bconotnic Tntollleenci: Comulttnc (KIC)t tec on Chcolcnlfipiedriority to determining tbe level of production of helium In tbe USSR because of the unc of heliua In guided clcsilcB and nuclear energy and Its other strategic applications. atcuch as the only known commercial iiource of heliumelluo-bearing natural gao, the problem wan referred to the KIC Subcommittee on Petroleum.

In7 the EIC Subcommittee on Petroleum agreed that tbe level of production of helium In tbe USSR could not bc estimated on the basis of the information available. It waa recccnaendedeport be prepared on helium In tbe USSR with emphasis on theoccurrence of helium-bearing natural gas and on the amount of helium which might bc extracted from such gas. IMo report undertakes to meet that need.

- ii

COKTEfffi

Natural Gas ln the

a,. Geological

b. Probable Occurrence and Distribution

Ural-Volga

Pechora River; Basin

Btavropca'ffcly

(k) Dsepr-COn

of Helium In the

of

from Natural

Appendix A. Production of Helium ln the. US

Appendix B. Productloo qf/Helium In the

Appendix C. Methodology

Appendix D. Gaps ln

Appendix E, Source

Tables

1- Estimated Production of natural Gafl In Selected Areas

Of the USSR,

Content of Natural Geo0 Wells in the

7 .

Requirements for Helium In the US, by Con-

sumer, Kleeol

Estimated Hecuireniento for Helium in the US,0

ill -

iiit rut lorn.

Following. Poffii

Figure 1. Data on Helium ShlppliiR Contalncrn Used In

the5

Figure 2. Simplified Flow Dlu^rois of tbe Helium

3. Photograph of Largeul US Reliua Plant,

Exell, Vena,iles North of

lv -

I

OCCURRENCE AND AVAILABILITY OK HELIUM IN TtiK USSR*

Suorjiry

The USSR probably haai billion cubic feet" of helium available from the helium-be or lng naturaleing produced in that country In the US,in loo cubic feet of helium arc available each year,he capacity of helium plants has been developed to extract only5 billion cubic fact annually. Hy the fiscal" hovever, it is expected that the capacity of these planta vill be expanded sufficiently to penoit the extraction ofillion cubic feet in order to meotrequirement ei.

Although there are ocverol Indications of production of helium in the USSt, data ore not sufficient to develop on estimate of the volume of Soviet production. If hellua is being extracted free, otic-fourth of the hellua:-be axing natural gas believed to be available In thc USSR, Soviet production would be about equal to that of the US, orone million cubic feet per day. Kb other country Is known to produce hellumarge ocale.

1. Helium-Bearing natural Gas in the USSR.

a. GeoloRlcrQ. Potential.

Petroleua, In thc fora of both crude oil and natural gas, Is found In coraerelal cuaatltlec. only in sedimentary bnslns or other

* The eetlmntcG and conclunlonB contained In tali report represent the bent judgment of ORR as

olumetric aciif.ure&ic&tu of helium and gac throughout thin report refer to the volume at standard atmospheric temperature and preaeure.

Theoretically, be extraer*-*

tha rwtffrlhnrbttent

In tliiu report, all references to thety, recovery, one, production of helium apply exclusively to he) lum In helium-bearing natural gas.

tutu on tho US ore reported oa the basis of fiscal years by the Bureau of Hlnifl of the Depart&cnt of the Interior, wtilch ir, chanced with production of helium In the US.

sedimentary arena of too earth. Both the US rind the USSR haveave-ngc Incidence of such ocdlmentary arcac The US, with 5of thc total Sand area of the world, linoercent of thcarea,illion square alien. The USSR, with Wof the total land area of thc world, hocercent of thearea,illion square olios." Thua thearea of thc USSRines that of the Ito, and thereforeresources of natural gas ln the USSR may equal orof Uie IIS. The wide diversity of geological conditionsthese resources occur In thc USSR nay bc compared to thageological conditions in the sedimentary areas of thc

the basis of known conditions In the US, there Is strongthat the USSR possesses natural gas containing helium in recoverable

b. Probable tecurrencc and Distribution.

On the basis of experience In thc US, two Indications ofhelium ln natural gao In tbe USSR arc the presence ofln quantitiesercent or more In the natural gaa and theof natural gas fron the older sedimentary rocks of the Paleozoic age. Such deposits of natural gas are still more likely to contain helium ln recoverable quantities if they overlie burled granite ridges or are ln an area of Igneous Intrusions.*

A survey of thc oreao in thc USSR which produce natural gas has resulted In the selection of four areas aa tbelikely to possess recoverable quantities of beilus.

ral-Volga Area.

A scientific monograph appearing5 contains theanalyses of natural ess In thc USSR that specify thomonograph reported thatnalyses of natural gas

froa the ural-Volga areaelium content rangingercent. Seven of the analyseselium concent of moreercent."*

Scrutinynalyses of natural gas produced in this area showsitrogen content of lessercent, and less

In the US the Bureau of Mines lias determined that, under existing conditions, helium cannot be recovered economically from natural gas that contains lessi percent, helium.

than one-half of the analysesitrogen content of leoo]<ercent." Another nource shows thot In fouri: gas In this area (Bugumolan,lnhay,Tuymoxy) Uie nitrogen content of the gao vorlcdo to " Moot of thc natural gnn produced In the area coacaFoueOZOla rocks of tiie Devonianfor the

ooutheaBtern part of the area, the Devonianoverlioo granites

and other cryotallloe basement rocks.

River Baaio.

The Pechorn River basin, vhlch ic north of thebae produced natural gas for .everel years. The geologicalIn this basin arc reported to be similar to those lo tbeAnalyses ofamples of natural gaoareaa nitrogen content runglng from '*rea ia isolated and could be thc olte of an unreportedthc extraction of helium.

Kray.

Inroadcast from Moscow clulmed thein Stavropol'skly Krayarge deposit of pure heliumeters,eters below the zone producingto tbe broadcast, Belov, thc chief geologist of

tho oil and gag industry at Stavropol', estimated that thc deposit woo very large and added that deposits of pure heliumery rare phenomenon. Bo odditional information on this reported discovery bos been released.

There ie considerable doubt as to the reliability ofatural deposit of pure helium lo unprecedentedhelium-bearing gas discovered in the USlthough large deposits of natural gas have

been fauna and developed in recent years In Stavropol'skly Kraythe Caucasus Mountains, most of the published analyses ofproduced in this area do not suggest the presence of helium,the nitrogen content is less thanutanalysesitrogen'content rangingthere are indications that older Paleoioic rock* underlieof thc area and aof Igneous intrusions extend into the area

In analyses ofr. in both the US and the USSR the percentage shown as nitrogenelium end other rare gases unless such usee ore shown separately. In the US, helium ie shown separately In the analynen reported by the llureau of Mines.

from Uic CoaCMOM Kauitalnn, nwcihIobtained froatlcoznlctones unlet] doco not favor tho occurrence, of helium.

nepr-Doa Itaoln.

Recent diocovcrioo of natural gas in tlie vicinity ofn bnoln haveitrogen content oo high9

percent. " ' Soae of these newly discovered depoolts are of the ittleorolc age, and..jbstantlal Paleozoic section may underlie thla area. There lr. also on igneous intrusion adjoining the area on the ooutu. These joelllve indications of hellum-bearlng naturalhe ncv ana exteuolve depnulto that are being discovered and developed In thla area suggest that .substantial quantities of helium may bc available.

The selection of tho four areas cited above does notthe exlotence of other undiscovered or undeveloped deposits of natural gaa which may contain helium ln recoverable quantities.

2. Availability of Helium In the USS*.

a. Technology of Extraction.

The availability of helium depends not only upon thcand production of helium-bearing natural goo but also upon thc technical ability to extract the helium from such goo. Thechronological review of significant developments regarding thc extraction of helium from natural gno in the USSR will indicate the level of Soviet technical ability in the use of this process.

As earlyU the USSR was sufficiently Interested In helium to contract with US nationalseport on the extraction of helium froa bellUQ-bcaring natural gas. Although the report was preparedecognized authority in this field, it contained little that had not been published previously.

There is evidence thatlant was built in the USSR near Moscow on the Saratov-Mo scow gas line to liquefy largeof natural go". quef led goo Id stored for subsequent use during periods of greatest demand, because liquefaction of helium--bearing natural gas Is essential to thc recovery of thelant which llquefloti natural gaa may include the relatively small amount of additional equipment needed to recover uny helium contained in the gas.

la J'/'OUSSI! ordered equipment for the liquefactionsupplier" in theequipment woo designed to liquefy

naturn) gas nt the rate ofiCO cubic feet per Hour, Loorodl meUul eylltnieci: unci) JO feet. In dl&rj'-Lcr twd ho ('eel high.ew of the items requested had been embargoed to the Soviet Bloc by tlie US, mitct of thly equipment was shipped to the ilSSR. An article pu llfilied In Moscow Ln iy>6tillsc eci^pleted substantially as planned and vau operatingatisfactory manner. The design, construction, and operation of tbe liquefaction plant iim,-eates that the level of technology in the USSR lo adequate to extract helium from natural gas.

A limited survey of the relatively large volume of technical RuiiBlon-lunguage literature which became availablerief article on the extraction of helium irom natural, gaa ln the USSR. ' The article Indicates that in the pretrcatnent of natural gas preparatory to the extraction of helium, operatingin the USSR6 wasevel with that in thc USAI. Thc author stated that the alkali batch process wue being replaced by the continuous TOnoetbanolamine process ln production of helium in thc USSR- Thio pretreatment involves the uoe of tbe continuous Glrbotol process using monoetlianolamine, which was patented in the US and which replaced the alkali batch process during World War II. "/ Another article appearing in Russian-language literature describes thc US helium industry and includes abibliography of data oc helium publiahed in tbe US.

That the USSR hasignificant technologicthe US in tbe production and transportation of liquidecen^report quotes Dr. Peter L.

Kapitsa, Director of the Institute of Physical Problems, as saying that liquid helium isbundant in the USSR that ithipped la railroad tank cars. Helium must be cooledemperatureew degrees of absolute zero, in order to liquefy it, und it must be maintained at that temperature If It is to remain In the liquid state. Although liquid helium ic produced in tbe US for laboratory uses, production of liquid helium ln large quantities and itsby rullrOad tank cars Is beyond uctual operating tecunology I" tbe US. Tbe advantages of liquefying helium for transportation, however, arcn thc US by"tbe Bureau of Mines and the Navy Bureau Of Aeronautics. Conventional methods of transporting helium In the US5 arc Shown in Another report Indicates that Soviet ability to liquefy helium in large quantitiesotential rather than, actual os lute os

* Po33owini', p. 6-

The foregoing evidence demonstrates that the USSR ponDcsnro the technical ability eeeentlnl to the lnrge-&cule extraction of bcllun froa natural gas.

b. Recovery from Natural Gas.

Ao previouslyour areas in the USSR produce natural gas that probably contains recoverable quantities of helium. Estimateg of production of natural gas In these areas* ore shovn in*

As shown in Tableroduction of natural gas in the four areao of the USSR moot likely to possess recoverable quantities of helium amountedillion cubic feet6 and Is expected to increaseillion cubic feet roduction of natural gas in similar areas of tho USwestern Texas, western Oklahoma, western Kansas, and New Mexico amountedillion cubic feet. "/ It is estimated that the helium available for recovery froa that portion of this gauercent helium or more amountedillion cubic feet, 9 percent of all of the natural gas produced in thee areas of the US

If the areas of the USSR producing helium-bearing natural gas shouldotential for recovery of hollun comparable to that of areas In the US listed in the preceding paragraph, thc USSR vould6 billion cubic feet of helium available for recovery. In the absence of more specific data on helium in the USSR, an estimateillion cubic feet per year is believed to be the best that can be made at this time

See> p.bove.ollows on p. 7-

6 -

SECRET"

l-lehum is shipped to points ol consumption in rdiluiay tank cars, dutomot/ye trailers .and'standard compressed das cylinders.

Bstiniatcd Production of Katural QW i* Selected Areas of tlie USSR

Billion Cubic Feet

Area

Pechora River basin Stavropol'skly Kray Dnepr-Don basin

fi/

b/

//

c///

1/

1/

by assuming un increase9 percent, the rateproduction in the USSRhole7 exceeded that

by assuming on increase9 percent, the rateproduction in the USSRhole8 is expected

reported production of natural gas in Komi ASSRillion cubic feet.

reported production of natural gas in the horth Caucasus in

'tO billion cubicis believed thatubic feet of this total cowb from the gasflelds In Stavropol * Some natural gas la produced In the old oilfields at Grotnyy

and Maykop In the North Caucasus outclde Stavropol' skiy Kray.

planned increase In production8 compared with that in

illion cubic feet.

by assuming an Increase ofercent, the rateproduction in tbe Ukrainehole7 exceeded that '

b.

i. Derived by subtraction of production in thc four selected areas

rroo tbo total production in thc USSR.

J*

AHBKOX A

ibokictiom ok helium iji hie us

1. Distribution.

Natural gooelium content rangingrace (lean1 percent)ercent in found throughout the US. During the7 the Bureau of Minos obtained andample of natural gaa from each0 veils intates. The distribution of the helium content in these samples is shown in Table 2.

Table 2

Helium Content of natural Cosb0 Wells in thc US aj

19Ld-*7

Proportion of

Helium Content

Samples

of Samples

Percent)

(less

9

and more

Analysis of those samples shows that helium inercent and more) occurs almost exclusively where the natural gas lo produced from tho older sedimentary rocks, primarily those of Paleozoic age, and* where tbe natural gasercent or more of nitrogen

These conditions Indicate only the possible preoence of helium; natural gas produced under such conditions docs not ncceaoarllyhelium. Ilaturul gnaeo containing recoverable quantities of helium also arc found usually la areas overlying burled granite ridges or associated with Igneous Intrusions.

2. Availability.

The Bureau of Mines entirjntco that, on the basisinimis hcllu= contentercent, there areillion cubic feet of recoverable helium ln proved reserves of helium-bearing natural gas in the US. In illion cubic feet of helium uere available Itct. the natural gna produced and marketed from these proved reserves. Because of tne jock or plant capacity, ies thanercent of this available helium vas recovered; the remainder was Irretrievably lost. The Dcpuri-raent of the Interior lo planning an expansion of plant capacity which would permit the conservation of icost of the helium now being wonted.

3' Production, Technology, and Coat.

Moreillion cubic feet of helium have been produced ln tbe US since large-scale production began Before World War II the annual production of helium ln the US never exceededil-lion cubic feet and averaged less than ono-half of that amount. In lOM, productioneakil] ion cubic feet as the result of an extensive expansion of plant capacity. 3 the wartime peak waa surpassed and In the fiscalillion cubic feet of helium were produced.* The current rate of production of helium Is approaching one million cubic feet daily.

The technology for extracting he31um from natural gas, which has been developed by thc Bureau of Kices, lo based on well-known physical lavs and involves the use of extremely low temperatures end high pressures. The incoming natural gas ia cooledemperature below tbe liquefaction point of Its hydrocarbon components At this temperature the mixture of helium and nitrogen lo recoveredapor and treated to remove hydrogen. This vapor lo compressed and further cooledrocess which liquefies the nitrogen and yieldsercent pure helium vapor. This helium then is refined5 percent purity by coolingiquid nitrogen bathinal purity of moreercent is achieved by passing the helium through activated charcoal maintained ot the temperature of liquid nitrogen. This process is shown graphically in* An aerial view of the largest helium plant ln the US to shown In

The gradual Improvement of technology for extracting helium and the Increased volume of natural gas procensed for this purpose have

This amount Includesillion cubic feet of heliumfrom underground atorage inffside Field and reprocessed. Following

served to reduce the coot of producing helium in the US. The sharp Increase In production and decrease in coot are Indicated by thetabulation:

Cost

$ Per Thousand

Year (Tnouoand CubicFeet)

to 7

The foregoing costs represent primarily expenses incurred In operation and maintenance and dote rained the prices at which helium was sold by the Bureau of Mines to other US Government agencies. Soles of helium to private consumers always included extra charges to cover thc estimated costs of depreciation and interest, and since1 these cocto also have been included in the prices paid by US Government agencies. The current price of helium la0ubic feet.*

t. Uses.

Historically thc US Kovy has been the principal consumer of helium, having receivedercent of total production, primarily for lighter than aircraft. Consumption by other components of the Department of Defense, by the Atomic Energy Commission, and by private industry is rapidly increasing, however, ax shown by Some of the strategic uses forecast for the fiscal0 ore shown inTable ft."-

In recent years the scarcity of helium has limited commercial sales to essential needs, usually related to national defense. Such uses, predominantly metallurgical. Include hell-arc welding and the production and fabrication of magneoiura, titanium, and other metals Inelium atmosphere is enoentinl. Other essential, uses are the detection of leaks, medicinal purposcc, and experiments inlaboratories.

iscountllowed to hospitals and certain other specialized consumers of minor quantities.

ollows on ollows on

- 10

'nor coattftuent in some neturalgases produced in the Southwest,

m.viet*

Qlhisis producedponapjily fa-ttefud value end is transported to fuel markets inef/nes

eichanje mctvm^^ssand returned to the pipeline.

c-o-

inarmed tyhtft

.removed est fits.

I s

6 0

elium plant.'

eicept he/run end an a;iquefied.

ceded still further byeptretmvessel

fy meter, by beet exchange ft

ebim isedrzdedtsi px.

elium-mtrwenmixture

hi enjtosfaftheiquid nt/ofrn

first mith mater.

uf the ndrigen mlhe

odied udodhiraum &r

subsequent useidnfcrjOo* cydr

@thenbyhejt Qfyfindaakguoix essd imsiersed

returmne Mount and mtrobw-

ieini,iuficd Flow Diagram ol ihe Helium Produclion Process

Tabic 3

Let loo ted Requiremento for Helium In thc US, by Consumer Fiscal

Cubic Feet

Flscul Year

1

Department of Defense

Energy CoraeilBolon

Bureau

Industry

total

Table

Estimated Acquirements 1'or Helium in tliooc Fiscal

Amount

Cubic Feet^

Department of Defense

Guided

Aeronautical research

. General

0.1

Breathing

Ihiclear reactors

*

Atomic Energy Commission

Production

Military

Development of

Other

Grand

b. Including the Ha*tonal Advisory Committee for Aeronautics.

2 -

APJ'KHDIX :(

PRODUCTI0T1 UK UKLIUM IHl

Thereimited (mount of fragmentary data on production of helium In thc USSR. Insomuch as this information Is generallyrather than quantitative and frequently of questionabletheoe data are inadequate for estimating the volume of Soviet production. The information now available may be summarized oh follows:

As previously indicated, Soviet Interest in production of helium dates back at least*

erman engineering Journallant at Dergacbevokiy fiiayanj that extracted helium from natural gas. 'The capacity of thc plant was given* cubicubic feet) of natural gas per day, and the helium content of the gasercent. Compared with the gas processed in tho US, this helium content Is very low. At beliuz plantr. In the US the residual natural gas remaining after the helium has been extractedercent helium. If it is assumed that one-half of

the helium in thc natural gas was extracted in thc plant In Dergachcvskly and that lt operated continuously at the stated capacity, thc annual production of helium would have amounted0 feet. Thisabout one-third of tho helium produced In the US

World War II, four helium plants were observedby prisoners ofof these plantssaid towas located at bergachi, which is inKhar'kovskaya Oblast, and may be the plant previouslybeing in Dcrgachevskly. Another helium, plant, reportedly onof Zhiloy in Azerbaydzhan ASSR, processed natural goawells3hen the gao was depleted. plants were reported at Saratov and Stalingrad, but nowas given concerning their size or operations.

*. risoner of war employedonstruction helperfrom7 to9 reported he workedfactory may have been connected with the plant

that rece.vcd UShere the liquefaction of natural gasargo ocnlo was reported to have begunI1. ' Natural gas

la available Lo this plant from two nourco, tlie muimva-Mjneov 'DIM* line and tho Saratov-Noccow pipeline. The nitrogen content of the gas from Daahava3 percent, and that of the gao froa Saratovercent. Thepipeline la one of thc principal outlets for natural gna from the Ural-Volga area, which ban been identifiedrobable source of helium." It may be assumed, therefore, that thc natural gas from the Sarntov-Moocov gae pipeline eontaino recoverable quantities of heliim. On the baale of the data available 'he plant at Moscow could produce as much asillion cubic feet of helium annually, which amount Is equivalent to production In thc US

5. ulletin published by the bureau of Minosibliography covering all technical and scientific articloo pertaining to helium that were known to have been published ' otall6 items were citedin the US abroad. Of this total,tems vere cited frca Soviet Journalo. Oftems classified under "Production ofhe USSR accounted for onlyhich were lioted as follows:

Item Number Ip-tlai

A.A. (Separating Helium from a

Gas Mixture). Husoian

C.I. (Thc Helium Industry in the United

States). Gazovocetrograd. Prlrodnule Gazui, Vol.aicJ

This bibliography indicates that before very little information on production of helium was published in the USSR, at leant in unclassified publications.

6. An article published in the USSR inthe productivity of the presently-operating installationshelium" from natural gas, but the article did notnumber of plants or quantity of helium being produced, or thcthe natural gas beingstatement that certain pro-

posed "technological and design changes will permit lowering consider" ably tho coot of commercial helium, vhlchaving up5 millionear in the operation of one aggregate" might indicate the approximate level of Soviet production of heliumomparison

See, (TI. p.bove.

- tk -

of thc contu of producing lie] lun ln the US ondorficlol

rate ofulileo toouldore reallotlc rate of exchange,aving of In the fiscal5 the total coothelium ln the US wno about US $jfigures

do not permit on estimate of production of helium In jie US^i, hut they suggest on avenue of approach if additional data become

7. Int the All-Union Conference oo low Tempera" ture Physics ln Moscow, Dr. Peter Kapltsa stated that the Institute of Physical Problems was expected to provide large quantities of liquid helium in the very near future. '

APPENDIX C

Tito method employed to estimate the availability ol* Dn3 i'm win; that of analogy with conditions In the US. Except for the effect of technology onhe enaloeouo factors ore natural rather than artificial and therefore are not subject to differences In the economic capebllltlcc of the two countries. The a? natural factors arc primarily geological and are well established withto thc occurrence and availability of helium in the US. Data on the geology of the USSR arc cufflclent to eatabllsh the analogous conditions governing the occurrence and availability of helium in that country.

Data on the distribution of helium in natural gas in the US and the geological conditions under which Itere derived frca the source cited and vere discussed with technologists in the Bureau of Mines, who verified them in principle. These conclusions were verified alsotudy of the manuscripteport prepared by the Bureau of Mines and scheduled for publication. 5V This report contains analysesumples of natural gas analyzed since lyVf.

* See,bove. ** See Tableppendix A, p.bove.

AlT-HHOJX

gaps.

p In Intelligence, on hellim In the USSR inon the nuvher, locution, capacity, and production of planto for the extraction of helium. In thc eboenco of ouch details the Ideal baole for estimating thc quantity of helium availableegion producing helluuv-benrIng natural, gaa is hy using the data on produc*-tion of natural gnc by the region ond the average content of helium of the gaa. Such data are not available on regions producing natural gas In thc USSR.

Many of thc available annlyseo of natural gon in the USSR refer to Individual valla rather than to fields or larger arcao. With oneoviet analyseu do not shov Ihe helium content of natural gaa. Cuch onalyuco follnv the practice of Including helium vith the nitrogen, ao that helium, if any, must be estimated. Additional analyses of natural gas in the USSR vblch shov heliumeparnte component ore needed.

* Sec, p.bove.

AJ'I'EJ.-JIX K

SCUIiOE REFERENCES

Evaluations, folloving the classification entry and designatedhove the following significance:

Source of Information

- Documentary

aeipletely reliable

sually reliable

C Fairly reliable

ot usually reliable

ot reliable

annot be judged

- Confirmed by other sources

- Probably true

- Possiblyoubtful

- Probably false

- Cf mot be judged

"Documentary" refers to original documents of foreign govem-cents ond organizations; copies or translations of such documentstaff officer; or information extracted from such documentstaff officer, oil of which cay carry the field evaluation "Hoc urn-ataxy."

Evaluations not otherwise designated are those appearing on the cited iocumcnt; those designated "RR" are by the author of this No "BR" evaluation la given when the author agrees with the evaluation on the cited document.

Original document.

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