Title
Sticking deep ice core drills: Why and how to re
cover
Author(s)
Gundestrup, Niels S., Johnsen, Sigfus J., Hansen
, Steffen B., Shoji, Hitoshi, Talalay, Pavel, Wi
lhelms, Frank, 庄子, 仁
Citation
Memoirs of National Institute of Polar Research
, Special Issue, 56: 181-195
Issue Date
URL
Rights
Type
Text Version
2002-03
http://hdl.handle.net/10213/1359
NATIONAL INSTITUTE OF POLAR RESEARCH, N.S.Gundes
trup, S.J.Johnsen, S.B.Hansen, H.Shoji, P.Talala
y, F.Wilhelms, Memoirs of National Institute of
Polar Research. Special issue, 56, 2002, 181-195
Journal Article
publisher
Additional
information
http://kitir.lib.kitami-it.ac.jp/dspace/
∬a tio皿al lm s titⅦt‘さ O r Il01a r R8S色且r Cll
Mem・NatIlnst・Pol＆rRes・，Spec・fssuc．56，I8）−］95，2002
餌戯喝dモモpiα00re血側鹿W叫月皿‖抑Ⅳ伽ー醐Ver
NielsS・GundestrupI，SigfusJ・JohnsenJ，Ste熊mB・＝ansen一，Hi（OShiShqii：，
PavelTalalay3and FrankWilhelms4
一助fl椚叫げC卸〝鳥呼〝・叫腑印Jげα甲如ね血品川ビ〟血咋／J仇
β〟−2川0（伽〝毎騨Ⅵ0丘飯竹川〃止
ヱ〟鹿川J血∫触おげ乃d〃〃吻J舐〟α〝dq〟細川川ク腫07
5瓜甲〃伽g〃Jげ肋ゆ如G紛”ビ叫飲食励め〟曙ぷ旭陀〟加ゎgJ〝頭鴫
ヱJ⊥加￠ZJ瑚∫￡掩お八め〟格納∬血
4J仲1仇必用玩畑和昭β珊鵬α岬〝■G仰αW
〟如珊助 ThcGISPdcepdriLlbccamestuckinJ98J，bulwas什ecthefb11。W●
ingycar・TheNGRIP／EPJCAdcepdriIlhassu鴨red什omtwobj＄Setb虻ks：
Thedri】1isstuckbothatNGRIPinGreenlandandatDomeCinArLtarCtica．
Bo（hcvenIsoccurredinaperiodwithroutinedriIljngandhjghproductivity・
The reasons fbr thc two events are believed to bc di能ren（，but thechosen
boTbhoIcliquidseemstobeproblema（ic．Thedensi6ercanadheretothcsurEhce
OrtheicecuttJngS，makingheicecuttings（OSinkintheliquid，insptteora−iquid
densityor935kg／m†．
］nsplleorchanged procedure＄and mod摘edconstruCtions．thcdri11t＃ame
S（uckagaln at NGRIP・Itwas什ecd usjnggIycol，making useofboth the
（emperatureandtemperaturegradientin（hehoIc．
L Whys鹿追唯一一皿鵬？
Stickingadrillisfhir）ycommonfbrshallowdri11ingsoperat］nglnannOn−1iquid丘11ed
（dry）aJlduncasedhole・Themostlikelyreasonsareproblemsinmovingcuttjngsaway
鮎mthcdri11head，andsnowfalJing丘omthesurfkdownontoporthedrill，mlingthe
narrowspacebetweenthedri”andtheholewall．
Adcepdrillingworkirlginaliquid負IledholeisinherentlymoresafiFirst，the
CuttlngprOCeSSitsdfislubricatedbytheholeliquid，（herebytosomedegrecpreⅥmtlngthat
theicecuttlngSareStickingtothedri11head・AIso，theliquidwi11he］pguidetheice
Cuttlngsawayfh）mthedrillhead・SomecuttlngSwi11notbepickedupbythedrilIright
away，bu（becausethedrillingliquidingeneralhasaslightlyhigherdensitythantheice，
anylCeChipsnotcol］ectedbythedrillwi11slowlynseinthchole，andcanbefi）teredout
Closertosurfke・Next・aCaSlngwithlidwi1JprotecttheupperPartOrthehole，PreVentIng
anysnowtodropdown・ThemorecomplicatcddrilJconstructjon fbradeep drilJ．
howeverlalsomeansthatmorecangowrong・Andasshownbelow，thcmodernand
morehight∝hdri11ingliquidsalsopossessesprob］emsoftheirown．
TheISTUKdd）］useda（Dye−3（Gundestrupeta］．，1984；Johnscnet a［．，）994）
bccamestuckin198）afterdrillingdowrlinthesi）tyice・ThecorebreaksbecamCd価cult，
and丘nal1ythecoredidnotbreak・（rapp）ng（hedrill・Itwasattemptedtofh光thedri11，
181
甘atio皿al】n s tltute of P0lar Res七arc b
182
N．S．GutldestrupetqL
usingthehammerintheantitorquesection，howeverwithoutsu潤S・Thedri11was］eft
fbrthewinterundertensioninthehole．＾1so，thedensityoftheholeliquidwasincreased
toensureaposltlVePreSSuredi肋・enCebetweentheholeliquidandtheice・Thefbllowlng
yeaTlthedrilJwasfねe，andinspeCt10nreVealedthaHheproblemindeedwascauscdby
corethatdidnotbreak，therewerenomechanicalproblems■ Tbecorewassoductile．tha（
thecorecatchers hadproduced10cmJonggroovesintheicecorefbnthehammering，
withoutcauslngthecoretobreak．AlaterlogglngOftheholeindicated，thatthecore
brokewithin3months（Gundestrupand Hansen，I984）・
Thc触t probkm wi【h（he EPJCA drill（GundestruP et al・，1996）happened at
NGRIPin1997atadepthof1371m．ThedritlingwascompIetelyroutine，Withvcryhigh
productivity．TheonJyanomalywasalittJehighJossofcuttings，bu（theloweringspeed
orthedriIlintheholedidnotshowanyaccumulationorcutt．ngs・MostlikeIy，thedrill
becamestuck，Simplybecausetheeoredidnotbreak，therebytrapplngthedrilIatthe
bottomofthehole．Unfbrtunately，thedepthorthestuckddlJwasatthetemperatuTe
minimumin thehote（−3TC）．Usingdi鮎rent techniques，it was虹temptedto place
glyco）attopofthedrill．butinJackofaclearirldica（ionorthestJCCeSSOfthis▼teChnjque，
abarreloftechnicalglycoIwaspumpedintolhehole，hopingthatitwoulddropdownto
thebottom、fh：eingthedrillduringthenextmonths．Thisdidnotwork，andthedrilIis
slills（uCk．Onreasonfbrthefailureof什eeingthedrillcouldbe，thatthereac（ua11ywas
ahigheramountoricecuttJngSintheholethananticipated・ExpenmCntSShowed，thal
thechosendensiGer（HCFC141b）adherestothei￠eCuttingsin thehole，makingthem
dense．Thetheorythenis，thattheseheavylCeCuttmgS“rained−’downontopofthedrill
in thedaysfb11ow］ngthestickingevent，paCkingbetweenthedriIlandtheholewaJl，
theTebye触tjvelymouldingthedrilltotheicecap．FigureIshowsamixtureofice
cuttlngSin drillingIiquid．ln thelefisample，theliquidis amixture ofD60and
HCFCI4Jbtoadensityof935kg／m3．Jntherightsample，theHCFC）4Jbisrepl且Ced
with HCFC123．臥）thsampleshavebeen stored aboutaweekiIt−I5CC，and shaken
shortlybcfbrethepicturewastaken．［nthesamplewith14fb．1heicecutt）nBSSeparateS
in3鮎ctions：Atthctop，WehavethelaTgericecrystals，刊oatingonLheliquid．SmalIer
icecrystalsarefloatingalmostweightlessintheliquid，andsomehavealT％dysedimen（ed
tothebottom．InthesamplewithHCFC］23asdens摘er．aJ）ice幻oatsinthe］iquid．A
testpe血rmedat−230Cshowthcsamepattern，althoughnotqulteSOprOnOunCed・
Based on this expenenCe，the drilIing procedures were chang由fbr the Dome C
dril］ingintheAustralsummeT97／98．First，theholewasⅢtered触quentlydowntothe
bottomofthehole，tOenSu陀thattheholewasclean．Next．thedri11rotation，andthereby
thedrillpumpwaLSS（aTtedabovethebot（OmOfthehole，andthedriL］sJowlyloweredthe
lastmeterorso，thereby pumplngaWaythecuttingsthatmayhaveaccumulatedatthe
bottom．Thisseemedtowork伽e，andinadditionthepumplhatpumpedthechips鮎m
thedrillheadtothestorageinsidethedrillworkedpe血tly，Withanegligiblelossofice
Cutlings．Everythingworked伽cunti］adepthof780m，Whereitwasdimculttostartthe
drilJing．Thedrilldidno（PenetlⅥte．Th！℃eatlemptsWeremadetostartthedri11ing，and
i（isassundthat（hedrillintotalpenetratedsay20cm・Thenitwasstuck．Theevent
is we11documented什om theIogglng Oftheinfbrmation hm the drilland surthce
eleetronics．Themostlike］yreasonfbrtheeventis，thatthecuttin夢WerenOtPuTnped
awayftomthedrillheadduetoam∝hanicalen・Or・Theresultwasaheavyslushatthe
Ⅶatlomall瓜Stltute of P8lar Researcb
StickingdcepICCCOredri1Is：Whyandhowtorecover
1＄3
鞄ノ．撤柳∬〝画冊血〟C打ノ市郎血朝粥加地加〝C打J㍊助力朗叩如
払断地肌血血日加ゆ血卸町鵬〆血相㈹Id血乱 丁αα〝両群加伽柳∬明姑
血呼一ぬ鵬d／一路加㈹よ曙如か血砂わβ′〃血相伽ゐゆす血血腹勒〟正
bottomortheholewasnotpumpedawaybeforetheactualdri）Iingstarted，（hecuttings
thengotsqueezedbelweenthedrilIheadandtheice，reSultinglnaStuCkdhll．
Theconclu5ionis，thatthetwoeventsareuncorrclated，eXCePtfbrthedcnsifierused
tocorTeCtthedensityoftheboreholeliquid．Andatbothevents，theheavyicccuttings
Createdbythedensi鮎rwasam往iorcontributortotheproblcms．Åsusual，Seヽ℃ralthings
need10gOWrOngbefbrcanaccidcnthappenS！
WhenthedrilljngresumedatNGRJPin1999，aneWdensifierwasuscd：HCFC123．
Thisdens沌erdidinacoldroomtestoverseveralwoeksnotshowanyslgnOfadheringto
icecutt）ngS，thusmakingthemdense．Thisalsoworked丘neinthebeginnJng，howeverat
depthsmorethan300m．icecuttlngStendcdtoa∝umulateatanimc柁aSlngrateaIthe
bottomoflthehoIe．Andatthesametime，themixtureofho［cLiquidandcuttlngSWaLS
difficulttopump．Theresu］twas，（ha（HCFC123underpressuremadetheicecllttlngS
even moredensethan thc HCFCt41b，and we had to replace theliquidin ordcrto
maintainastabledri11ing．
WerLOWknew，thatthefinericecuttJngSIostinthehoIcwoulddroptothebottom．
Thiswascontrolledbyhavinganightshi尺別teringtheholeal1thewaytothebottomeveTy
甘ationalInstltⅦte of P81ar Research
184
N．S．Gund苓tmpdl正
night．AIso，befbrethedri11wasstarted，itwasloweredclosetothebottom，andraised
fhst．Theideawas，thatthetutbulenceshouldremovethecuttlngS丘ornthebottomofthe
hole，makingthemeasiertoco11cctinthedrillbefbrethedri11ingresumed・Thistechnique
workedwe11untiladepthof2500m，Wherethecablehadtobechanged・
Thenew cable−aStandard oceanographiccable as usual−WaS Ord耶d tar什∝・
Having2500mofnewcableintheholenaturallyproducedsomeheavyresidueinthehoIcl
andtheproductivitysu飴rdsomewhat・However，insp】leofdimiT）ishingproblemsinthe
Rrstdaysa触rthecabIewaschangedbecausethecablewascleanedin thehole，the
problemsseemedsoontoincrea＆，andalreadyatadqpthof26Wm，Wehadproblemswith
aheavyblacksubstancetha‡tendedtoclogthehol岱inthedri116］terscTun・This
required extended cleaning operations betwcen each run，and a shoTter CO一℃1ength・
＾1thoughtheproductivitysu晩red，theweekly production s（illexceeded140m／Week・
TheproblemswithheavylCeCuttlngSfhllingtothebottomoftheholeincreascdfhstwith
incTeaSlngpreSSureandtemp訂ature・Thelongerruntimcalsoincreasedthesedimenta−
tionbetwecnruns，makingtherunSmOreandmoreirregular．Onagoodrun，themotor
cuTrentisstableunti）theendoftherun，Wherethe仙erinthechipchamberstarttobc
blocked．1rtheBlterwaspardyblockedbycontaminantsoricecuttings，themotorcurrent
rises．Byholdingbackon（hedrillcable，the卿etZ％tionsIopped，andthepumpinthe
AIterwouldcleanthedri1l，makingitreadyfbrthenextcycle（Fig．2）・Astimewenton，
moreandmorecIeaningstopswererequird，andwealsoaddedmtqmnsdurirlgtheday，
inadditiontothenightfi1tering．At2餌X）m，icesta血tofbrmonthecutters．which
madeitditficulttodri11withalowpitch．Finally，aladepthor2931m，andahole
temperatureOf−60C，thedri11becamestuckSurldaymominga鮎rarunWithmanylost
cuttmgs，andarunWith8drillingrestarts．）twasclear，thatthecausewaspackingof
Cutt］ngSinthespirals，renderingthepumpine触tiveatld触allystickingthedrillatthe
鞄ヱ 肋馴〝りおー柳川瓜 乃g増加用符血伊戒両班翔少￠肝（金印如あ伽柳
〝g血一触脚血〝加＆ 伽gα建．か刑㊥Jわ解
封a tlo malIh S tlt叫t e O f P01ar R e s￠arCも
SdckingdecpICeeOredrjlls：Whyandhowtor∝OVer
185
drjllhead．
1D畑1roeo▼e町
HavingthedTmStuCkatthistime，2daysbefbreapJanned且ight，Jquiredfhstaction．
Withinhours・therangeofthecableloadtransducerwasaqjusted，givingaca［ibratedcable
loadrangefbrthefullstrengthofthecabIe・AIsothestandortheholeliquidwasraised
toensureoverpre5iSureaI（hebottomorthehole・Thepu】1inthe cablewasincreased
manua11ytoacabtetensiono‖7脇）N■ ThetensionthensIow．ydecreasedto）4（珊N．
Evenwhilethecablewastcnsionedmanually，thefbTCeinthecabJetcndedtoreturnto
l棚N・althoughwithanincreasingtendency・After4mofeabIewaswoundmanual1y．
ilwasdecidcdtostop・TheicehigheruplSCOlder，anditcouldbemoredi爪cuL（toget
thedril抽光furtheraway什omthebottom・一rthedriLJwasraisedtoomuch，i（WOuldalso
notbepossibletokeep］tirnmersedinglycol．
Thenextday・thedrillwassti11stuck・Then，aLterseveralunsu職軋1attemptsof
reIeasingtheinnercorebarreltiomtheddl］，aSa触ypininthetransmissionbroke，making
furtherattemptsofreleasJng）tlmPOSSible・Atthesametime，mOrehoseswererequested
fh）mCopenhagen・Th胱eXtrahoseswouldmakeitpossibletodumpglycoIbelowa
POSSibIehighdensityhoteliquidlayerJuStbelowthecasln＄．Nochangeincabletension
COuldbeob＄erVed・Ttwas（hendecidedtoT℃1ease160［ortechnicalglyco）（ant血盟e）in
thehote・Glycolisrelativeheavy（TndustrialSoIvents＝andbook）（Fig・3），andexperi−
mentsshowedthatwecou］dassumetheglycoJtothl）intheho］ewi（haveloc】tynOt］css
than20cm／s・In4hoursa鮎rdropping（hegJycol，itshouldbeactivea（thedriIl，andwe
jO
・JO
・細
T叩00用h帽Pq
・20
f扱ヱ 伽〝叫′すα脚／㈹鹿＝血相肌＝桝靴＝伽岬刑一批
・1（）
O
甘a tl￠n al ln s tit tlt e O f t10la r R e＄e a r C b
N．S．GundestrupetOL
186
＿封
80
−28
一刀
Tem血u仲lOCl
−18 ・旬
・10
鞄A 乃岬Ⅶル〝げ血〝G尺げ加昨月∂血
胡
胡
︻UL空ヨ邑○ト
0 10 20 卸 側 部 ∞ 70 00 00 100
∨01ul鵬血no帽紬l％l
f砂丘 加納g〝叩ぬげ〃坤gめ仰J／明拍γ牒鹿紬鱒
封atlo＝1Instltute or†01ar tose8rCb
S（ickingdccplCeCOrCdrills：Whyandhowtorccover
187
Shouldbeabletoseeatcmperahredecreaseinthedri11temperattlreSenSOrS・
Atthesametime，itwascl翰r，thatwehadnoindicationabouthowmuchtheglycoI
WOuld be diluted whenitarrived atthc dri11，29Wm downinthe hole．Fromthe
temperatureSCnSOrSinthedrill，thebottomtemperaturewasknowntot光about−60C（Fig．
4），ヱe・beIowtheg）ycolmeltingpointof−130C・Itwasthenclear，bycombit）ingthe
Calculated hole temperature棚dq）thwiththe glycoIfhec2ing proper（ies（Fig．5），
Polderman（1969），thattheoptimalso］utionwouldbetodrop仇）Zenglycolinthehole．
ThisglycoIwouJdstayfbzenuntiladepthor2750m．andarrivecssentiallyundilutedat
thedri11・Mondaya鮎rnoon，eXperimentswereperEbrmedtofh，CZethcglycol，uSingaCO2
触extlnguisherascooJingmedium・ThecxpenmCntSreVealed，tha（atatemperaturcof
−320C，thetechni仏IglycoIwasonlyhalrfrozen．ACryocooICClOO丘㌍Zerandpure
glycoIwasthenrequestedandarrivedWbdnesdayev￠nlng，3daysahrthcevent（Ogether
Withpuremonoethyl飢egけcol−anOnCOlordsubstance．1twasnottrividtolocatethe
COrTeCtglycolasonecorrlpanyaloneo飽red60di鮎renりypes and grades，allcal1ed
SOmethingwithglycol！
Befbremidnight，theCC］00fiTeCZerWaSSetup．andsomcbagswith1echnicaJgIycoI
placedinafbamboxtonTeeZe．Later，thepuregIycoIwasalsoplacedinthefh5eZer．1t
tumedout，thatthetechnicalglycoldidnot触zeat−280C．Thursday．experlmentSOn
howto丘eezethepuregJycoIcontinucd（Fig．6）．Wed∝idedtouseplastichoses，Sealed
inoneend，andkeeptheothercndabovethecoolingliquid．AIso，Wedecidcdtocutthe
什0雄ngJycolinpiecesnotLar辞rthan5cm，inordertoavoidthatitcouldbetrapped
betwecntheholewal1，andthecabIe．Final1y，at2100，3．5kgoffナ0訟nBlycolpillswere
dumped，fb1lowedby2．5kgat0030．AtO200，aCOOlingortheelcctronicsectjonofthe
drillwasobservedindicatingthatthefrozenglycolhadreachedthedrill，andwasactive
fな丘 Cん廟血亡扮〝伽q／伽卸gか戚
甘itlo＝1Ⅰ血5ト【lt」tナ ＜f Polar R eseartb
N．S．Gundcstrupet aL
18S
there．＾tO509，thecabletensioTldecreased丘omlO590Nto5690N・Thetemperatures
indicatedbythedhllwasthen−90Catthecoolestscnsor・Thedri11wassIowlypulled
tosurfhce．AtO707，thedri11wasbackonsurfhce．
AfieT a Short celebration，theinner core barrelwas removed．Thue was heavy
packingaroundthecozecatchers，anditwascleaf，thalthedri11hadぬntrappedhcl℃（Fig・
7）．ALso，OneOfthespiralswaspackedwithiceatthebottom・Thespacebetweenthe
innerandoutercorcbaJTdswas創1cdwithcuttlngS，butthecouplir）gbetwemthedri1land
therotatlrLglnnerCOrモbaLrT℃1wasclean・ltwaseasytoremovethecorebarrel，andthere
werenoindicatiorlSWhyithadnotbeenpossibletoseparateitfh）mthedrill・Thepump
didnotshowanyanomalie＄・The68cmtongcorewasextractedu血galcohol・itwasin
twopICCeS，withtheupper3cmplCCeShowingslgnOrWear・OTltOpWaSahardpacked
25cmLongslushcake・Thecoreshowed7incremeTltSOfshor（erandshorterpenetration・
Thechipchamberwasneadyempty．
3．B8ili喝
Havingdropped L60lofglycolintheholewithnoapparentreactiononthedri11
rneant，thatwecotJldassumcaboutItonsofg】ycoIslusha（thebottomofthehole，With
aconsequentdamageoftheholewal1・Thisslushneededtoberemovedfbrthedrilling
tocontinue．［nordertogetaT＝mpTuionoftheslushproper（leS，SeVCraltestsampJeswjth
rnixturesorholeliquid，iceandglycoIwerestoredat−6QC，thesamctemperalu托aSthe
Ⅳa tloIlal IIIS tlt LIt e O f J）ola r R e s e a r cll
Stickin＄deep．￠eCOredri11s：WhyandhowtoTeCOVer
189
glycolinthehole・Dmingthetest，thetemperatureinthesaLmplewasmomitored，andit
Stayedcloseto−6dC・Theset6tSamples血owedtheslushtobeathickhomogenous
SubstarK：e，thatshouldberelativelyeasytocollectwithabai1er・A］so，Weperformed
expenmentStOSeehowfhsta5cmpleCeOrfiozenglycoIwouldbedissoIvedinthemixture．
A鮎r4days，thepiecewasstil］onlypartlydissoIved・Thisindicated，thatthcglycol
melting／dissoIventra（eisheavilydependentonpressure，Le．intheboreholeatapressure
Ofabout280Bars，themelting／dissoIvementrateisapproximately20timesfhsterthanat
normalpre＄uTe・Thiswaslatercon爺rmed，Whenthebailergotstuck・Fridqyabmoon，
thefirstsIushrunWaLSmadeusingashortbai1er．Fi吋twomabovethebottomofthe
hoIc，theelectronicsshowederrors・andexcesscurrentwasdrawn什omthesurfhcepower
SuPply＝Theel∝trOnicswasparLlyshorted・Puuingup，theshorLdisappeared・Going
down，theshortreappeared・Foroperat）ngthebai1er，itisesscntialthattheelcct
WOrks・Ifnot，thebottomvalvccannotbeclosed・muS，thebai］erwas伽al1yo
bylowenngitfおtintotheslush，aJldimmediatelyclosingthevalve，befbretheel∝trOnics
Shorted．Thispr∝edurewasusedfortheBrsttwosIushrurlS．Thenitwasdecidedto
Changetoalorlger（8m）bai1er・Usingthe）ongbailerSaturdayJuly29，itonlyshorted
Onthe触trun・Tbeelcctronicssurvivdtheabu9e，althoughthebras＄CentreCOnductor
intheantitorqueshowedcIcarsigr10fel∝lroLyticcorrosion．
rtwasd准cuIttoremovethcgJycoJ伽mthetank，becauseit舟ozeonthewayup・lt
neededtobeheatedbytheHermanNelsonheaterandcove托dwithanairductforone
hour・befb陀thcglycoIcouldberemoved・Theg）ycoIwasthenmoved10aSlushfhctory．
First，themoresolidslushwasremoved・Next，theholeIiquid／slushwasmoved10a
COOlingdrum・Whencool，theboundarylayerbetwcenglycoland1101eliquid was
dcteTTninedbyaconductivitymeasurement，andtheholeliquidrecycled・Theg］ycol
mixturewasdeposited・Usingthispr∝edure，Weminimizedtheenvironmentalimpactof
theoperationtodumpIngSnOWCOntainmgglycol・
Thebailingopcmtionwasneverroutine・lncon（rarytothcexperiments，theglycol
intheholebuildsolidbrid9e＄atthetoporthcglycoIIayer・WespeCulate，thatthe
temperaturegradientintheholemaketheglycolmix（ureunstable，CreatIngOneOrmOre
COnVeCtioncells（Fig・8）・Thisconvectione触tivelyremoveice付omthelowerpaTtOrthe
hole，anddeposititatthetoportheslushlayer，WherethetemperatureisIower，andle＄
icecanhedisso）vedbythcglycol・Tnordertopassthebridges，andfilIthebarrel，itwas
requiredtogoirltOthe由ycolwithaspeedofabout30cm／S．Andevenwith（hisspeed，
thepenetr叫ionalmoststoppedatbai】ingrun15，MondayJuly31at88mabovethe
bottomofthehole・ThenascraperW鱒mOuntedverticallyonthebottomvalveorthe
bai1er（Fig・9）・TheideawastousethisvalvewithscrapcraLSaSOttOfdrjllbyrotating
thedri11motorbackwards・Theva）veisnotiJltendedfbrcontinuosoperation，SOWe
expectedsomeproblerns・AIso，thesurfhadri11controIprogramwasmodificdinorder
tomakethisformofreversedri11ingeBLSier・Fina（1y，0・5kgof什ozenglycoIwasusedto
SO鮎ntheglycolbridge＄．
Itworked，arLduntilrun23，ataSludhcightof75mwehadreasonablepenetration．
ThentheglycoIsJushbridg6SgOttOOStrOng・ThescraperWaSthenmodi6edonAugust
Itoextcnd5mmbeJowthebailer，andlmmfurthcrout・Lowcnngthisdevicewith15
Cm／swhilerotatingthescraper，brokethebridge・Wewereawarc，thatthebai1ing
Opera（ionnowwashighlyrisky・Theglycol蝕虹ingEactorywasTeeStablished，and3kg
Na tloれallI15tlttltモ O f P01a r lle s e ar（：b
N．S．Gundestrupe（aL
190
鞠＆ 血伽〃陀d脚W〆妙〝J加血由良 川ビβw血川〃油〃加d如伽岬餌付
訂d飽〃￡
of丘ozenglycoIwasreadyatanytime，Shouldthebai1ergetstuck・
Thebai1ingthencontinuedinrelativeroutineuntilAugust3・Whereoneofthe4wires
inthecableshortedtothesteclarmour．Thefaultywirewasdisconnected・Withtherisk
ofloslngthewiresinthecable，itwasdecidedtologtheboTtholebefbrecontinulngthe
桝a tloIlalIn s tltⅦt e O f P01a r R e s e ar e b
StickingdeeplCCCOredrills：Whyandhowtor∝OVer
さ
恕叫l
穂川 血血加わ〝〃〃〟αめ”〟助す血ぬ〝鼻血 撤加血α肋！血ゆ血昭伽〟邪ぬ抽
励肋gJ血鱒′助α〝朗α）仇
baiJing・TheloggingshowedtheRrstsignoftheholewallbeingdissoIvedbytheglycol
at2820m，t10mabovethebottomofthehole（Fig．‖）．＾t2880m，50mabovebot（Om，
thediameter触quentlyexceededtherangeofthecaliperSOf174mm，COmparedtothe
undisturbeddiameterof］29・5mm・Note，thattheloggingdidnotgoallthewaytothe
bo（tom，at34mabovethebottom，thetooIshortedduetotheconductivesubstanceinthc
hole・ThediameterCurVeCan−abitspeCulative−beexplainedbythetechnicalglycoI
StaTtlrlgtOdissoIvetheholeat2820m，beingexhaustedbeforereachingthcdri111IOm
futherdown・Thefr0舐nglycoIs（artedtobeactivea12880m，andremainedactived
tojts丘oz甲COnditionunti）reiLChingthedri11．
Followlngthelogglng，the24houIbailingshiLtcontinued・Again，itgotmoreand
moT℃dimculttocontinucduetobrid廟乱 Friday，August4，atrun42，amOre囁托SSiⅥさ
SCraPCrWaSrnOunted・t（SticksIcmotLtOfthebar托1，andlmmtotheside．Theangle
is80deg，andithas
．
inotdcrtopenetra（ethebridges，thatscemtobuildup，almos（asfhs（asweb且iled．
Bailingcontinuedin24hrsh脆・ltwasstill托quiredtolowerthebailerwith30cm／sin
Ordertobreakthebrid？SlbutSundaymomingAugust6，itscemedthatwe伽a11ygot
downtotheglyco11iquid：A鮎一（hebridgewasbroken．thcbai1crwashan如g触inthc
holeatadepthoflOmabovcbottomofhole・Thesamehap匹nedfbrthenextrun＃53，
thebridgewaspenetrated・andthebailerlowered3mfiuhanglng・Pullingup，thebai）er
潔atlonalIns t＝川t色 Of†01ar Re＄earCb
N．S．Gund怯truP〟〃上
192
加害喜脚
130
†40
1分
・帽0
Ho旭d8mderlmml
17【l
鞄アイ．β由仰ねγq／加わ㈹γわ仔力臆
wasstuck！Jmmediately．0．6kg＆ozengJyco）wasreleasedinthehole・ttisworthnoting，
thatthebottomorthebailerwassituatedwherethedrillwasstuckprevious）y，andthe
diameterortheholemaybelessthanforthereglOnabove，WherewewouldexpeCtthat
theglycolhadinc陀鮎edthediameterSigni6cantly・MBLXimumcabletensionusedwas
15∝ON，The bai1er wasleRwith a cabIe tet）Sion at the bai1er or55（氾N．Based on
temperattJreStbm（heelectronjcs，theglycoJwasactivearoundthedriIllatest6hoursa触r
thedycoIwasrele出血．
MondayAugust7，thetemperatureatthee）cctt℃nicsectionwentdownto−J20C，and
thetemperaturedistributionindicatedthelowerpartortheelectronicsectiontobecolder
thanthetop，SuggeStlngthattheactiveglycoIwasmovingdown．AIso，theliquidinthe
holewasraisedto67m，enSurlngapOSitivepressuredi蝕renceatthebottomofthehole・
Tuesday，the baiIer was not、fl恍．At the same time，the electronics showed the
incJinationtoincreasewithtjme．Wehad鮎Sumed，（hatif【he bailerwasstuckat the
bottom，theinclinationshoulddecreasewithtime，aStheglycoIcreatedmorecIear
arOundtheupperPartOfthebai1erandantitorque・Thattheinclinationnowincreased，
COuldbejnterpretedasthebai）erbeingstuckatthetop，andTlOtatthebottorn・Jtbecame
Clear，thatadi飽陀nttreatmCntWaSrequired．Duringthenight．wecoT）tinueddropping
lkgor舟ozengl匹01eachho叫althesametimea5㈹kgfわ託ngl匹OIwasprepar由in
3cmplastictubcs．Thetubeswereplacedinholesinacavcbelow−13CC・At1800，
Wednesday，the60kgwasdroppedwithin15min．Thelkg／hrtrcatmentcontinued・At
2203，aStePOnthecable，andthetensiondropped丘omapproximatelyl・5tons10560N・
＾t2209，thebailerwass］owlyraised，andat2335itwasonthesurfhce，greetedbyourlast
ya tlo nal In s tlt u t七 O f I101a r R e s e ar cll
StickingdeeplCeCOredrills：Whyandhowtorccover
193
鞠ノヱ 伽伽げ占α肋祓g〃育8〝毎d〃J∫〟ゆ比 助〟伽！血御I励り細則劇画戒 コ職
叩〟〃お躍几 乃∼叩毎血血c血細押通われα肋○喝カ〟血仰〟〟わ胱
冒言暑登竜言責至急至
ら0
10
20
aO
40
05
80
仙」mboro相成伽qmn8
物上ユ 伽すbα肋g叩肌摘肌
Champagne・Therewereseveralpieceso用・OZenCOnCentratedglycolintheantitorque
SeCtioTt，atabouthalroftheironglnalsize・ThcsepleCeSmuStOngmate鮎rntheglycol
droppeddown3hourearlier・Comparedtoourtests，thisisamuchhigherdissoIventrate．
甘a tlomalInstltⅦte Of Polar te5earcb
N．S．GundestrupeE qL
194
1tsecms，thatthereactionrateof劇ycolishigh1ydependentofpressure．Inspcctionofthe
bailcranddama辟tOtheleafspnngsintheantitorquerevcaled，thattheumithadbecn
stuckattheantitorquesection，andnotatthebailerend（Fig・12）・Our70kgorglycol
droppedslowIythelastdqyshadthenmeltedatthcantitorque・andsIowlyseepedtothe
bottom，makingtheholelar評rbclowtheantitorque・First whenit伊tthe massive
amountofglycol，thcglycoIconcentrationaItheantitorquewasla聯enOughto丘∝il・
Ch∝kingtheloghook，WCCOuldidentifytheincriminatlnglayerasahardlayer20mabove
bottom．Nexttheshort（4m）bai1erwasmounted．Thepurposewastogetanideaabout
thestandoftheglycol，andirpossjble陀mOVeSOmeOfit・Thebai1erwentsmoothlydown
to30mabovethebottom，atWhatdepthitwascIosedandhoistedtos血．Herethe
towertiltingmotorbroke，StOPpingfhrthercleahingattcmptsforthe拙OTl．Thebajler
COntainedlittleglycol，andweexpectthegtycoltobeinthelower20rnoftheho］e・
▲ Sllmm■叩
The authots have had the mixed pleasul℃OfbeinglnVOIvedin6deep dri11ing
Opera（ions，Dye−3，GJSP，GRIP，NGRJPI，DomeCandNGRJPn・ln40fthesedri11ings，
thedrillbecamestuck，andtwodrillswerelost．Twocases（3irweincludeDomeC）were
duetod雌cultiesinbreakingthecor℃．Two（3ifweindudeDomeC）werecausedby
thedensi鮎rused．ThemoreadvancedHCFCliquidsusedtoa句ustthedensityofthe
boreholeliquidcanadhcretotheicecuttlngS，CaUSlngthemtosedimenlin（hehole．This
PrOpertyishigh1ydependingonpressureandtcmperature，andthataliquiddoesno（Show
any anomalyat atmospheric pressuredoes notin any way makeit unprobIematic as
derLSifierinadri11iTlgOperation．Theold CFCsdid notshowthisanomaly，andthe
propertIeSOfthenewesttype，theHFCsarenotknown・
ThedissoIvementrateor什ozenglycolishighIydependentonpressure，Atatest，a
pleCeWaSnOtCOmPletelydissoIvedin4daysatthesurfhce，Whereasthcsameamountof’
dissoIvementtookonly4hoursat280Bar．Å1so，theglycoIsolution，atleastattempera−
turescIosetothepressuremeltingpolnt，CannOtberegardedasastagnantsolution・Due
totheLemperaturegradientinthehole，Circulationce11sarefbrmed，mOVlngiceftomthe
deeperpartshigherupinthehole．
OnedriJIwas触，Simplybykeep］n＄alargefbrceinthecable，andensuringapositive
pr闇路uredi飽rencein（hehole．Usingthet∝hniqueordroppingfrozcnglycol，Onedri11
WaSreCOVered什omadepthofalmost3km・Usjngthistechnique．itshouldbepossible
tofree adri1］stuckin adeephole，prOVideditisstuck at a depthwithincTtaSlng
temperatuTtwithdepth．Pya4justingthegJyco］／watermixtureofthe舟ozen pills，the
tahniqueshould be usefhlattemperaturesdowrltO apprOXimately−30BC．Atlower
temperature＄，thee触tivenessor（heglycoJm？ybetooJow，andthecorrectwater／glycoI
mixtu一号toocritical．
R￠鎚一モー伽5
GtJndestruP．N．S．ar）dHanscn，B．L．（1984）：Bore−holesurvqa（Pyc3，SouthG陀enland．J．Glaeiol．．
：抑，282−288．
GundestruP，N．S．，Johnsen，S．J，andReeh，N．（1984）：lSTUK一旦deepicecorcdriI］system・CRREL
■■
封atlo＝1ⅠれStltute of Polar Res￠arCh
S（ickingdcep］CeCOredriIIs：Whyandhowtorecover
195
S匹：、Rep．，糾−3一、7−19．
Gundestrup．N・S・∴bhnsen，SJ．e・t aJ．（1996J：ThcEPICA dcepiceeoredril】．TheOceaTlandthe
Poles、ed．byG．Hempcl．Jena，GustaYFischerVerlag．279−2S7．
Johnsen，S−J・．GundcstrupN・S・，Hansen，S．8．，Schwander，J．andRufli．H．（1994）：Thenewimproved
VerSionorthelSTUKicecoredrill・Mcm．Natllnst・PoIarRes．，Sp∝．Issure，4？，9−23．
】ndustrialSo［ven（SHaJldbook（1991）：4thcd．，Park Ridge，NewJel常y．USA．477．
PoJdcrman、LDt（1969）：EthylenearLdPropylcn亡GlycolandThcirWaterMixlures，Presentcdatthe
AnnLJalMeetingofAmcrican SocietyofHeatingand AirConditioning Engincers，1nc．in
Philadelphi8、ねnu町y2る一班．
仰加ぬ朋L卑摘1∴抑鋸∴ぬ−鹿d椚α他所Jα叩抒d5卸柵ねrクスヱβOナノ

A Switched-Capacitor Multiplier/Divider with Digital and Analog

ごくイ ∩づη ::]]]蒻 ]:::]]11緻 Tvr:.flu:ar: o dendo loooe,