-
Caving 2014, Santiago, Chile
486
Geomechanical evaluation of large excavations at the New Level
Mine - El Teniente
E Hormazabal SRK Consulting, ChileJ Pereira Codelco,ChileG
Barindelli, Codelco, ChileR Alvarez SRK Consulting, Chile
Abstract
The New Level Mine is a 130.000 tpd panel caving project set to
start in 2017 at the El Teniente mine.VP-NNM CODELCO
(Vice-President Office of the New Level Mine) is currently
finishing a detailed engineering design of the underground mine.
The evaluation considers, the design of the crusher cavern Nº1
located in the Braden Pipe, which is a waste rock chimney located
in the central part of the ore body. A geo-mechanical study has
been carried out to evaluate the stability of the planned
infrastructure and to provide recommendations about the design of
underground caverns and galleries, including support. As part of
this study, empirical methods, two-dimensional and
three-dimensional continuum models have been developed and applied
to evaluate the influence of the high stresses and different
geotechnical units, on the mechanical response of the excavation.
This paper introduces general aspects of the New Mine Level
underground project and discusses in particular geo-mechanical
analyses and design carried out to evaluate stability and support
of some of the large excavations involved in the project.
1 Introduction
ElTenientecoppermineislocatedinthecentralpartofChile,CachapoalProvince,VIRegion,about50kmNEfromRancaguaCityandabout70kmS-SEfromSantiagoCity(Figure1).
At the ElTenientemine, the copper andmolybdenummineralization
occurs in andesites, diorites
andhydrothermalbrecciassurroundingapipeofhydrothermalbrecciascalledBradenPipeandlocatedinthecentralpartoftheorebody.TheBradenPipehastheshapeofaninvertedcone,withadiameterof1,200matsurfaceandaverticalextentofmorethan3000m.TheBradenbrecciasarewasterock.Therefore,thedifferentproductivesectorsofElTenienteminearesurroundstheBradenPipe,andthemaininfrastructureandaccessshaftsarelocatedinsidethepipe(Pereiraetal.2003).
TheNewMineLevelisa130,000tpdpanelcavingprojectsettostartin2017attheElTenientemine.Theminingprojectconsidersusing
thepanelcavingmethod tominecopperore.TheVice-PresidentOfficeof
theNewLevelMine(VPNNM)hasfinishedadetailedengineeringevaluationof
theproject,whichconsiderstheconstructionandoperationofseveralminingunitstobeoperatedindependentlyfromeachother.
Amongthemostimportantelementsofthepermanentmininginfrastructuretobedesignedandconstructedfirstarelargecrushercaverns,designatedasSChNº1,SChNº2andSChNº3caverns.Thesecavernsarerequiredtoreducetheoresizefromtheoperationminingsectorsthatwillguaranteethecontinuedoperationforaperiodof50yearsormore.
The objective of this paper is to present general aspects of the
design of one of the crusher
chambers(SChNº1cavern),includingtheinterpretationofgeotechnicalsiteinvestigationdataanduseofempirical,analyticalandnumericalmethodstodeterminetheappropriatepermanentsupporttobeconsideredforthiscavern.
-
487
Numerical Modelling
Figure 1 El Teniente mine location in relation to Santiago and
Rancagua cities in the central part of Chile
2 Geotechnical characterization
Until the early 90’s the Braden Pipe was considered an almost
homogeneous body, composed by
aconcrete-likerockcalledBradenbrecciaand,initsperimeter,byabrecciacontainingcoarserrockblocks,calledMarginalBreccia(Pereiraetal.2003).However,thebehaviorobservedatdifferentsectorsoftheBradenPipeindicateddifferencesthatcouldonlybeexplainedbythepresenceofdifferentbrecciatypes.Therefore,acomprehensivegeologicalcharacterizationoftheBradenBrecciawasdevelopedinthepast,whichallowedamuchmoredetailedzonationoftheBradenPipeandthedefinitionofseveralbrecciatypes(Floody2000&Karzulovic2000).Themainbrecciatypesarethefollowing:
a) SericiteBreccia–thisbrecciaconstitutesamajorityofthepipe.
b)
ChloriteBreccia–foundprimarilyinthesouthernportionofthepipe.
c)
TourmalineBreccia–characterizedbylargeclastsandvein-likeoccurrence.
d) MarginalBreccia–hardbrecciaattheboundaryofthepipe.
For eachof thesebreccias, there isvariability in the sizeof the
fragmentsor clasts and in themineralconstituentsandalterationof
thematrixcement. In theBradenSericiteBreccia, thereappears
tobeaneffectoftheratioofSericite/Quartzcontentinthecementtothecompressivestrengthofrocksamples.Figure2representsaplanviewcontainingthelocationofcrushercavernNº1andshowingthedifferentgeotechnicalunitsasinterpretedfromtheavailablegeologicalandgeotechnicalinformationfromthesite.Themain
geotechnical units are the SericiteBradenBreccia unit
(BBS),ChloriteBradenBreccia
unit(BBC),TourmalineBradenBrecciaunit(BBT)andtheDaciticPorphyryunit(PDAC).
-
Caving 2014, Santiago, Chile
488
Figure 2 Plan view at mine level 1790 of the Crusher Chamber SCh
Nº1 location, indicating the main geotechnical units as interpreted
from available geotechnical information (taken from SRK, 2014)
Ingeneral,theBBS,BBCandBBTunitsarerockmassesofgoodqualitywithaBieniawski’sRMRvaluelargerthan70;fordetailsabouttheBieniaswki’sclassificationsystemseeBieniaswki(1989).Forexample,Figure3showsaphotographofsomerepresentativecoresofthemaingeotechnicalunitsatthesitelocationofSChNº1;solidandintactcores,fewjoints,lowfracturing,acommoncharacteristicoftheBBS,BBCandBBTunitswhichtranslatesintogoodqualityrockmass,canbeobservedinthephotograph.
Aspartofthegeotechnicalcharacterization,adatabasewithgeotechnicalinformationfromsiteinvestigations(geotechnicalboreholes)atElTenienteMinewasanalyzed;thisdatabasewascreatedandismaintainedbyVP-NNM(VCP2010aandVCP2010b).Inparticular,valuesofgeotechnicalparametersdescribingthequalityoftherockmass,includingFractureFrequency(FF),RockQualityDesignation(RQD),IntactRockStrength(IRS)andBieniawski’sRockMassRating(RMRB).
BasedongeotechnicalwindowmappingofdriftsandgalleriesclosetothesitelocationoftheSChNº1,acharacterizationoftherockmassqualityintermsoftheGeologicalStrengthIndex(GSI)andBarton’sQ-systemvalueswererevised(fordetailsaboutthesesystemssee,Hoek,1994,Hoek&Brown1997,Hoeketal.2002;Bartonetal.1974;GrimstanandBarton1993;Barton,2002).Theresultingrangeof
thesevalues,expectedtobeencounteredduringexcavationoftheSChNº1,isshowninTable1.
-
489
Numerical Modelling
a) b)
c) d) Figure 3 Cores of the main geotechnical units at the site
location of the SCh Nº1.a) BBS. b) BBC. c) BBT and
d) PDAC
Froma structural geologypoint of view, the sitewhere the crusher
cavernwill be emplaced has
beenreferredtoas‘BrechaBradenMarginal’(or‘BradenBrecciaMarginalStructuralDomain’).Analysisoftheavailablegeologicalinformationhasrevealedtheexistenceofthreesystemsofminorfaultsandtwojointssets.Table2summarizestheorientationofthesestructuralsystems.
Thein-situstressstateconsideredforthedesignofthecrushercavernSChNº1wasobtainedfromover-coringtestsperformedatXC-01-ASsiteNº5(undercuttinglevel1880).Table3summarizesthein-situstressfieldatcrushercavernlocation.
Values of strength and deformability for all the geotechnical
units were computed according to
thegeneralizedHoek-Brownfailurecriterion(Hoeketal.2002;Hoek&Diederichs,2006)andfollowingsomespecificrecommendationstotheElTenienteminebyDiederichs(2013).Themechanicalparameterswerederivedfromlaboratoryunconfined,triaxialandtensiletestingofrocksamplesandestimationsofvaluesofGeologicalStrengthIndexfromgeotechnicalwindowmappinginthemainaccesstunnel(TAP),driftsandgalleriesnexttotheSChNº1location.
-
Caving 2014, Santiago, Chile
490
Table 1 Classification systems values of the rock mass at the
SCh Nº1 location
UGTB RQD (%) RMRB89 Q’ GSI
BBS 70–100(80) 60–92(72) 1.2–250(14) 56–90(69)
BBC 94–100(98) 70–85(77) 40–100(70) 63–82(72)BBT 80–100(90)
72–82(75) 5–71(23) 61–80(73)
PDAC 79–100(89) N/I N/I 65–86(72)
():Meanvalues.
RQD:RockQualityDesignation(Deere,1963).Q’:modifiedBarton’sQ-system(Jw/SRF=1).
GSI:GeologicalStrengthIndex(Hoek,1994).RMRB89:RockMassClassificationsystem(Bieniawski,1989).
N/I:Noavailableinformation.
Table 2 Structures at the site location of the SCh Nº1 (VCP,
2010b)
SETSMinor Faults Joints
Dip/DipDir Nºdata Dip/DipDir Nºdata
S1 84°/125° 12 75°/324° 34S2 83°/035° 7 35°/010° 21
S3 76°/172° 6
Table 3 In situ stress field representative of the site location
of the SCh Nº1
Principal Stresses Magnitud (MPa) Bearing (°) Plunge (°)
σ1 50.73 344.0 -7.8σ2 33.11 75.5 -10.7σ3 26.50 218.6 -76.7
Table3summarizesthemechanicalparametersfortherockmass,forthethreegeotechnicalunitsanalyzedwiththeHoek-Brownmethod.[InTable4,miistheHoek-Brownintactrockparameter;σciisunconfinedcompressivestrengthoftheintactrock;γ
is thespecificgravityoftheintactrock;Ei is
themodulusofdeformationoftheintactrock;GSIistheGeologicalStrengthIndex;mb,sandaareHoek-Brownrockmassparameters;andERMandνarethedeformationmodulusandPoisson’sratiooftherockmass,respectively.
Tocalibrateandvalidatethestressfieldandrockmasspropertiessomeback-analysesweredonetocheckifthebehaviorpredictedusingthesepropertiesagreeswiththeobservedbehavior.Two-dimensionalplane-strainmodelswere
constructed fordifferent sectionswithdifferentgeotechnicalunits
andorientations,involvingsectionsforwhichoverbreakweremeasured.ThemodelsweredevelopedusingthefiniteelementsoftwarePhase2(Rocscience2009),whichallowsanalysisofexcavationsinplane-strainconditions.
Figure5showstheresultsfromafiniteelementback-analysisofoneofthesectorsconsideredfortheTAPtunnelinChloriteBradenBrecciaunit.Thelightgrayzoneintheroofindicatesfailurebytensionand/oryielding,andtheblackcurveshowsthemeasuredoverbreakeach5malongthetunnelaxisinthisparticularsector.Differenttunnelorientationswithinthesamegeotechnicalunitwereconsideredforthisanalysis.
-
491
Numerical Modelling
TheseresultsindicatethatthegeomechanicalpropertiesofthedifferenttypeofbrecciaspresentedinTable3areagoodestimateoftherockmasspropertiesforthesetypesofmassiverock.
Table 4. Summary of rock mass strength and deformability
parameters for the different geotechnical units according to the
generalized Hoek-Brown method —see Hoek et al., 2002; Hoek &
Diederichs, 2006.
UGTBγ GSI σci
miσt Em
vc φ
(KN/m3) Mean value (MPa) (MPa) (GPa) (kPa) (°)
BBS 25.9 70 81.1 11.00,768
29.31 0,207,336 34
0,384* 5,180* 33*
BBC 26.6 72 77.4 12.00,782
25.60 0,207,578 35
0,391* 5,350* 34*
BBT 25.4 70 100.0 8.01,302
23.01 0,207,448 33
0,651* 5,260 32*
PDAC 25.8 73 144.5 28.50,662
34.55 0,2012,078 48
0,331* 8,500 43*
(*)UbiquitouspropertiesconsidersJennings(1970)criterionwithak=0.3.
3 Support requirements for the crusher cavern according to
empirical methods
Figure6showsanisometricviewforthecrushercavernthatconsidersmainlythedumpingchamber,apronfeeder,crusherchamber,mainsilo,mainfeederandlift.
BasedonthelargeexperienceofexcavationoftunnelsandcavernsindifferentrockunitsatElTenientemine,usingthetraditionalmethodoffullfaceblastinganappropriate(temporary)supportconsistinginrockbolts,steelwiremeshandshotcretewereproposedfor
thecavern(SGM-I-011/2006,VCP,2010c,amongothers).
Apreliminaryestimationofthequantityofpermanentsupporttouseduringexcavationwasdoneusingempiricalmethods.ThemethodsconsideredwerethosedescribedbyBarton(1974),Palmström&Nilsen(2000),Unal(1983),Hoek(2007)andHönish(1985),amongothers.Thesemethodsgiveguidelinesforpermanentsupportrequirementbasedonseveralofthegeotechnicalindexesdiscussedearlieron,suchasvaluesofRQD,QandRMR.Table5summarizesthecharacteristicsoftherecommendedsupportforSChNº1accordingtotheabovementionedmethods.
Duetotheintrinsiclimitationsoftheempiricalmethods(particularlyinregardtotheassumptionofisotropyofstressesandrockmasscontinuity),thesemethodswereusedasafirststepinselectingasupporttypefor
theSCHNº1; the actual verificationof theproposed supportwas
carriedout using
tri-dimensionalnumericalmodelsasdescribedinthenextsections,whichamongothers,allowedincorporationofseveralgeotechnicalunitsexistingintherockmassandinsitustressfieldshowedinTable3.
Theacceptabilitycriterionforpermanentsupportwasestablishedbasedonfactorsofsafetywithrespecttofailure(incompression)ofthesupport.Basedontypesofsupportsusedandsuggestedlengthspansfromempiricalmethods,factorofsafetyof2.0forpermanentsupport(forstaticloadinganddryground)werejudgedappropriate.Inthisregard,aliteraturesurveydidnotrevealtheexistenceofestablishedrulesforfactorsofsafetytoconsiderforcavernoflargedimensions(asthecaseoftheSChNº1).Forexample,Hoek
-
Caving 2014, Santiago, Chile
492
(2007),suggestanacceptabledesignisachievedwhennumericalmodelsindicatethattheextentoffailurehasbeencontrolledbyinstalledsupport,thatthesupportisnotoverstressedandthatthedisplacementsintherockmassstabilize.Pariseau(2007)suggeststhattheloadactingonthesupportforlargeexcavationshouldnotexceedhalfthevalueofthestrengthofthesupportmaterialof(shotcreteorconcrete)—i.e.,thiswouldmeanconsideringafactorofsafetyofatleast2.Forwedgeandblocksfailuresinalargecaverndesignafactorofsafetyof1.5to2.0iscommonlyusedasacceptabilitycriteria(Hoek,2007).
Figure 4 Results from a finite element back-analysis of one of
the sectors considered for the TAP tunnel in BBT unit. The light
gray zone surrounding the tunnel section indicates failure by
tension and/or shear, and the
blue curves show the measured overbreak each 5 m along the
tunnel axis in this particular sector
Figure 5 Infrastructure considered for the geomechanical
analysis in relation with the main geotechnical units
-
493
Numerical Modelling
Table 5. Summary of preliminary permanent support recommended
for the SCh Nº1 as derived from application of empirical
methods.
Excavation B × H (m) Sector
Barton (1974) Palmstrom & Nilsen
(2000)
Hoek (2007)
Unal (1983) Hönisch (1985)
PatternLc (m)
Lc (m) Shotcrete Thickness (mm)
BBS BBC Lb (m) Lb / Lc (m) BBS BBC BBS BBC
DumpingChamber 24,3×8,8
Roof 1,3x1,3to1,7x1,7m;Shotcrete
120-150mm
1,7x1,7to2,1x2,1m;Shotcrete
50-120mm
7.5–8.1 5.8 5.6/9.74.1–14.2 6.3–11.2
100-150 100a150
Walls 2.4–2.6 4.4 N/A 50(min) 50(min)
StorageHooper 14,3×21,2 Walls
1,3x1,3to1,7x1,7m;Shotcrete
120-150mm
1,7x1,7to2,1x2,1m;Shotcrete50-90mm
5.7–6.2 4.0 5.2/7.4 3.8–12.5 6.0–9.8 50-150 50-100
ApronFeeder 9,2×10,8
Roof 1,3x1,3to1,7x1,7m;Shotcrete
90-120mm
1,7x1,7to2,1x2,1m;Shotcrete40-90mm
2.8–3.1 3.2 N/A2.1–6.2 2.8–5.0
50(min) 50(min)
Walls 2.9–3.2 3.0 3.6/3.8 50-100 50(min)
CrusherChamber 16,8×43,6
Roof 1,3x1,3to1,7x1,7m;Shotcrete
150-250mm
1,7x1,7to2,1x2,1m;Shotcrete
90-120mm
5.2–5.6 4.4 4.5/6.7N/A N/A
50-150 50-100
Walls 11.7–12.7 5.3 8.5/15.3 150-200 150-200
LoadingHooper 17,0 Walls
1,3x1,3to1,7x1,7m;Shotcrete
90-150mm
1,7x1,7to2,1x2,1m;Shotcrete50-90mm
5.2–5.7 4.6 4.6/6.8 3.1–10.0 4.5–7.9 50-150 50-100
B: SectionLength. H: SectionHeight. Lb: BoltLength. Lc:
CableLength.
4 Three-dimensional numerical analysis of the crusher cavern
excavation
Three-dimensional models implemented in the finite difference
software FLAC3D (Itasca 2007) wereconstructed for the main
infrastructure of the SCh Nº1 (see Figure 6). The three-dimensional
modelsincorporated only the permanent support (with characteristics
described in the next section) and
theproposedexcavationadvance,coincidingwiththeminingdesignexcavation.
Thepurposeofthismodelwastoaccountfortheactualthree-dimensionalnatureoftheexcavationproblem;themodelallowedwalldisplacementsonthelargeexcavation,extentoftheplastic-failurezonearoundthewallsofthelargeexcavations,andtheperformanceofthepermanentsupporttobequantified—i.e.,theverificationoftheacceptabilitycriteriaintermsoffactorofsafetydescribedinSection3.Ingeneral,majorprincipalstress(s1)reaches60to80MPaintheupperpartofcrusherchamberandapronfeeder(seeFigure7a).Unconfinedstress(s3<4.0MPa)areobservedbelowofthefloorofthedumpingchamber(seeFigure7b).Also,amaximumdisplacementof4cmisobservedinthefloordumpingchamberaftertheexcavationofthecrusherchamber(seeFigure7c).Maximumdisplacementsof5cmareobservedintheintersectionof
thecrusherchamberwallsandapronfeederandintersectionof
loadinghooperandmainfeeder(seeFigure7d).
-
Caving 2014, Santiago, Chile
494
Figure 6 Three-dimensional numerical model of the crusher
cavern. The figure shows the 93 advance intervals considered for
the excavation in different colors. The model, which incorporates
only permanent support, was
constructed using the finite difference code FLAC3D —see Itasca
(2007)
Analysis of results from these three-dimensional models allowed
to conclude that the support
(withcharacteristicsdescribedinthenextsection)satisfiestheacceptabilitycriterion—i.e.,afactorofsafetyof2.0forpermanentsupport.Figure8aand8bshowntheresultsforthedoublecablesinstalledintheroofofthecrusherchamberandthefinalexcavationofthemodel.
Thevaluesof loads resulting inpermanent liners (i.e.,
thevaluesof thrust,bendingmomentandshearforce) were recorded for
each of the large excavations analyzed. The values of support
loading
wereplottedincapacitydiagramstoverifythatthefactorofsafetyvalueswerebelowadmissiblelimits—foradiscussiononthemethodologyinvolvingverificationofsupportusingcapacitydiagrams,seeHoeketal.
(2008);Carranza-Torres&Diederichs (2009).For example,Figure8c
represents
capacitydiagramsforapermanentsupportofthickness0.3mintheapronfeederroofforthefinalexcavationofthemodel.Inbasicallyallthelargeexcavations,loadingintheproposedsupportanalyzedwiththecapacitydiagramapproachwasfoundtobewithintheadmissiblelimitsoffactorofsafetymentionedearlieron.
-
495
Numerical Modelling
Finally,toverifythesupportrecommended,awedge/blockanalysiswasperformedbasedonthestructuralinformationprovidedinTable2usingkeyblockteory(Goodman&Shi,1985)andthesoftwareUnwegde(Rocscience2009).Figure9showstheapplicationofkeyblocktheorytothedumpingchamberroof.Allthekeyblocksintheroofsandwallsforallthelargeexcavationswereverified.
a) b)
c) d)
Figure 7 Representation of the results in the model sliced by a
cross section plane located at the midpoint of the apron feeder.
Represented are: a) major principal stresses after crusher chamber
excavation, b) minor
principal stresses after crusher chamber excavation. c)
displacements after crusher chamber excavation and d) displacements
for the final excavation model
-
Caving 2014, Santiago, Chile
496
a) b)
c)
Figure 8 Support performance for some of the main large
excavations. a) Axial force for cables in the crusher chamber roof
at the end of excavation. b) Resulting axial force for cables
installed in the crusher chamber at the end of excavation (yielding
load, pre-stressing load and factors of safety of 1.5 and 2.0 also
are shown). c)
Capacity diagrams for shotcrete liner in apron feeder at the end
of excavation
-
497
Numerical Modelling
Figure 9 Dumping chamber section showing maximum removable
blocks for each JP superimposed on the stereographic projection of
the JPs. To the upper left, the analysis for the roof with Unwedge
program to verify
the support recommendations for the JP 1011 block (shaded in
red)
5 Proposed crusher cavern support
Basedonexperienceindesignoflargeexcavationssupportandontheapplicationofempirical,analyticalandnumericalmodelsdescribedinprevioussections,forthelargeexcavationscrossingthegoodqualityrockmassunits(BBS,BBCandBBTunits),permanentsupportwith
thecharacteristicssummarizedinTable6wereproposed.Thetemporarysupportconsistsmainlyofrockbolts(andwiremesh)withquiteuniformcharacteristicsformostofthelargeexcavations.
Forthelargeexcavations(dumpingchamber,storagehooper,crusherchamberandapronfeeder),inwhichhighstressconfinementintherockmasscouldtranslateintogroundinstability,heavierpermanentsupportproposed.
Table 6 Summary of permanent support proposed for the Crusher
Cavern SCh Nº1
Excavation B (m) H (m) SectorCables*
ShotcretePattern Length (m)
DumpingChamber 24,3 8,8
Roof 1,0x1,0 10 H30t=300mmWalls 2,0x2,0 8
StorageHooper 14,3 21,2 Walls 1,5x1,5 14
H30t=150mm
ApronFeeder 9,2 10,8Roof 1,0x1,0 14 H30
t=200mmWalls 1,5x1,5 12
CrusherChamber 16,8 43,6
Roof 1,0x1,0 15 H30t=300mmWalls 1,5x1,5 15
LoadingHooper 17 - Walls 1,5x1,5 12
H30t=200mm
B: SectionLength. H: SectionHeight.(*)
Allthecablesaredoublessinglestrandoff=15.6mm,additionallyasteelwiremeshC443wasrecommended.
-
Caving 2014, Santiago, Chile
498
6 Conclusions
ThispaperhasdescribedseveralaspectsoftheprocessofdeterminingthepermanentsupportforthelargecrushercavernSChNº1attheNewMineLevelprojectatElTenientemine.Thecrushercavernistobeexcavatedinarockmassofgenerallygoodquality(BBS,BBCandBBTunits),inamediumtohighstressenvironment.
Thesupport recommendedforcrushercavern,asdescribed in thispaper
isnotdefinitiveandwillhavetobeoptimizedonceconstructiontechniquesareselectedinafuturephaseofdesignoftheundergroundinfrastructure.
Thecharacteristicsofthesupportrecommendedforthecrushercavernarebasedontheassumptionoftherockmassisdryandthatdynamicloadingonpermanentliner(e.g.,duetoblastingduringfuturecavingoperations)isneglected.Also,asensitivityanalysisforHoek-Browmparameters,ubiquitousmodelandan
incrementof the in situ stresswasconsideredand
theproposedsupportwas found tobewithin
theadmissiblelimitsoffactorofsafetymentionedearlieron.
Intermsofpermanentsupport,consideringthecriticalimportanceofcontinuousoperationofthecrushercavernforatleast50years,apermanentconcretelinerofatleast0.3metersthicknesswasjudgedappropriate.Thispermanentsupportthicknesswasestablishedbasedoncurrentpracticeusedincivilengineeringtunnelprojects,andnotbasedontheempiricalmethodsdescribedabove.
Acknowledgements
TheauthorswouldliketothankCODELCOandinparticular,Mr.PabloVasquezChiefoftheEngineeringDepartmentofVP-NNMProject,forgrantingpermissiontopublishthispaper.
References
Barton,N,Lien,R&Lunde,J1974,Engineeringclassificationofrockmassesforthedesignoftunnelsupport.6(4),189–236.
Barton,N2002,‘SomenewQ-valuecorrelationstoassistinsitecharacterizationandtunneldesign’,Int.J.RockMech.&Min.Sci.,vol.39,Nº2,pp.185-216.
Bieniawski,ZT1989,EngineeringRockMassClassifications,JohnWiley&Sons.
Bieniawski, ZT 1993, ‘Classification of RockMasses for
Engineering: The RMR System and
FutureTrends’,ComprehensiveRockEngineering,(J.A.HudsonEd.),vol.3,pp.553–573.PergamonPress,Oxford.
Carranza-Torres,C&Diederichs,M2009,‘Mechanicalanalysisofacircularlinerwithparticularreferencetocompositesupports.Forexample,linersconsistingofshotcreteandsteelset’,TunnellingandUndergroundSpaceTechnology,vol.24,Nº4,pp.506–532.
Deere,DU1963,‘Technicaldescriptionofrockcoresforengineeringpurposes’,RockMech.Eng.Geol.,vol.1,pp.18-22.
DiederichsM 2013b, ‘SummaryReport of Findings
andRecommendationsBased
onNNMTechnicalAdvisoryMeetingsElTenienteNewMineTunnelProject’,21-25October2013.
Floody,R2000,‘EstudiodeVulnerabilidadGeológico-GeotécnicadeChimeneadeBrechaBraden.FaseI:GeologíaComplejodeBrechasBraden’,ReportGL-044/00,SuperintendenceofGeology,DivisionElTeniente,Codelco.
-
499
Numerical Modelling
Goodman,R&Shi,GH1985,‘Blocktheoryanditsapplicationtorockengineering’,PrenticeHall.USA.
Grimstan, E & Barton 1993, ‘Updating the Q-system for NMT’,
Proceedings Int. Symp. On
sprayedconcrete–ModernUseofWetMixSprayedConcreteforUndergroundSupport,Fagemes,(Kompen,OpsahlandBergeds),Oslo:NorwegianConcreteAssn.
Hoek,E1994,‘Strengthofrockandrockmasses’,ISRMNewsJournal,vol.2,Nº2,pp.4-16.
Hoek,E&Brown,ET1997, ‘Practicalestimatesof
rockmassstrength’,
InternationalJournalofRockMechanicsandMiningSciences,vol.34,Nº8,pp.1165–1186.
Hoek,E,Carranza-Torres,C&Corkum,B2002,‘Hoek-Brownfailurecriterion–2002edition’,NARMS-TAC2002,MiningInnovationandTechnology,(H.R.,W.Bawden,J.Curran,&M.TelesnickiEds.),Toronto–10July2002,pp.267–273.UniversityofToronto.(AvailablefordownloadingatHoek’sCorner,www.rocscience.com).
Hoek,E&Diederichs,MS2006,‘Empiricalestimationofrockmassmodulus’,InternationalJournalofRockMechanicsandMiningSciences,vol.43,Nº2,pp.203–215.
Hoek,E.Kaiser,PK&Bawden,WF1995,SupportofUndergroundExcavationsinHardRock.Rotterdam:Balkema.
Hoek,E2007,PracticalRockEngineering,coursenotesavailableonlineathttp://www.rocscience.com.
Hönisch, K 1988, ‘Rockmassmodelling for large underground
powerhouses’, NumericalMethods
inGeomechanics,EditedbyG.Swodoba,Innsbruck,Austria,vol.3,A.Balkema,Rotterdam.
Itasca2007,FLAC3D.FastLagrangianAnalysisofContinua.Version3.1.User’smanual.(www.itascacg.com).Minneapolis,Minnesota.
JenningsJE1970,Amathematicaltheoryforthecalculationofthestabilityofslopesinopencastmines.PlanningOpenPitmines.ProceedingsofInternationalSymposium(ed.PWJVanRensburg),Johannesburg,pp.87-102.Balkema,CapeTown.
Karzulovic,A2000,EstimacióndelaspropiedadesgeomecanicasdelasbrechasqueconformanlapipaBraden,TechnicalNoteNºDT-CG-00–04A.Karzulovic&Asoc.Ltda.Chile,submitedtoDivisionElTeniente,Codelco.
Palmström,A&Nilsen,B2000,EngineeringGeologyandRockEngineeringHandbook.NorwegianRockandSoilEngineeringAssociation.
Pariseau,W2007,Designanalysisinrockmechanics,Taylor&Francis/Balkema.
Pereira,J,Russo,A&Karzulovic,A2003,‘GeomechanicalPropertiesoftheBradenBrecciasatElTenienteMine,Chile’,SoilandRockAmerica2003.12thPanamericanConferenceonSoilMechanicsandGeothecnicalEngineering.39thU.S.RockMechanicsSymposium.Cambridge,EEUU.22-26june2003,pp723-727.
Rocscience2009,Unwedge.UndergroundWedgeStabilityAnalysis,Version3.0,Toronto,Canada.
Rocscience2010,Phase2,FiniteElementAnalysisforExcavations,Version7.0,Toronto,Canada.
SGM-I-011/2006,DefinicióndeEstándaresdeCalidadparaElementosdeFortificaciónySoporte,InternalReport.(inspanish)
-
Caving 2014, Santiago, Chile
500
SRK2014,‘AnálisisdeSecuenciaConstructivayDiseñodeSoporteSaladeChancadoNº1’,TechnicalreportsubmittedtoVP-NNMCodelco,Abril.(inspanish)
Unal,E1983,Designguidelinesandroofcontrolstandardsforcoalmineroofs.PhDThesis,PennsylvaniaStateUniversity.
VCP 2010a, ‘Análisis Geomecánico Caverna de Chancado’, Technical
report
T09E205-F1-VCPNNM-36000-INFGE04-3100-001-P.FeasibilityStageNLMproject,Codelco.(inspanish)
VCP 2010b, ‘Caracterización geológica y geotécnica Sala
deChancadoN° 1 - Fase
II’,T09E205-F1-VCPNNM-36000-INFGO04-3100-002-P. Feasibility Stage
NLM project, Codelco. (inspanish)
VCP 2010c, ‘Validación Diseño de Cavernas’, Technical report
T09E205-F1-VCPNNM-36000-NOTGE04-3110-002.(inspanish)