how do you know you’re in a world class nickel camp?world...
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How do you know you’re in a How do you know you’re in a world class Nickel camp?world class Nickel camp?world class Nickel camp?world class Nickel camp?
Steve BeresfordSteve BeresfordMEGWA Jan 2009MEGWA Jan 2009
The individual intrusions within the cluster are The individual intrusions within the cluster are connected in 3D!connected in 3D!connected in 3D!connected in 3D!
Slide courtesy Dawn Evans-Lamswood
OutlineOutlineOutlineOutlineIntroductionIntroduction•• World class World class –– do we know what it means?do we know what it means?•• ConfidenceConfidence
Discovery HistoryDiscovery History•• Geology and predictive conceptsGeology and predictive concepts
Mineral systems and Target contextMineral systems and Target contextDeposit summaryDeposit summaryCamps Camps –– what are they?what are they?•• World class deposits are clusteredWorld class deposits are clustered
I t i ti it d idI t i ti it d id•• Intrusive connectivity and corridorsIntrusive connectivity and corridors
Staging systems and camp footprintsStaging systems and camp footprints•• Accommodation space and stress regimeAccommodation space and stress regime•• Accommodation space and stress regimeAccommodation space and stress regime
ConfidenceConfidenceConfidenceConfidence
Through predictive conceptsThrough predictive conceptsMineral Systems approach Mineral Systems approach (do more than use the word (do more than use the word (do more than use the word (do more than use the word holistic)holistic)L th l f ld L th l f ld Learn the lessons from world Learn the lessons from world class discoveries. Visiting class discoveries. Visiting deposits are only junkets if deposits are only junkets if that is your attitudethat is your attitudeyy
Mineral systems approach Mineral systems approach -- understand the target contextunderstand the target context
OREOREDEPOSITDEPOSITDEPOSITDEPOSITSETTINGSETTING
DISTRICT DISTRICT ––SCALESCALESETTINGSETTING
PROVINCE/SUBPROVINCE/SUB--PROVINCEPROVINCE--SCALESCALETECTONIC SETTINGTECTONIC SETTING
GLOBAL GLOBAL -- SCALE GEODYNAMIC SETTINGSCALE GEODYNAMIC SETTING
Hronsky
World class deposits NiWorld class deposits Ni--CuCu--PGE are not PGE are not simply larger ‘common garden’ depositssimply larger ‘common garden’ deposits
Schodde and Hronsky 2006
World class NiWorld class Ni--CuCu--PGE deposits PGE deposits -- excludingexcluding komatiiteskomatiites-- excluding excluding komatiiteskomatiites
Sudbury CampNi metal tonnes
Duluth
y p
Voisey's Bay
Pechenga
Nk ti
Nebo-Babel
Selebi-Phikwe
Nkomati
0 5000000 10000000 15000000 20000000
Kabanga
Source: Host websites
0 5000000 10000000 15000000 20000000
Red line denotes 1.3MNiT cut off of Schodde and Hronsky (2006), a rough approximation for world class
Understand there is a Understand there is a continuum of Nicontinuum of Ni--CuCu--PGE stylesPGE stylescontinuum of Nicontinuum of Ni CuCu PGE styles PGE styles
and one predictive or detective technique will NOT workand one predictive or detective technique will NOT workand one predictive or detective technique will NOT work and one predictive or detective technique will NOT work for all stylesfor all styles
MgO
RaglanKambaldaNebo-BabelJinchuan
32% 7%Kabanga
PechengaPerseveranceMt Keith
Voisey’s Bay TatiNoril’sk
Magnetics Gravity
RaglanMt Keith Nebo-Babel
Jinchuang Gravity
Kabanga
PechengaPerseverance
Kambalda
Voisey’s Bay
TatiNoril’sk
PechengaRaglan KambaldaVoisey’s Bay
Noril’skJinchuan
Depth of emplacement
Base Surface
Valmaggia Perseverance
Mt KeithNebo-BabelJinchuan
Sally Malay
Base of LC
Surface
Pechenga
Raglan KambaldaVoisey’s BayNebo-Babel
Noril’sk
S source
Crustal
Valmaggia Perseverance
Mt KeithJinchuan
Mantle Crustal
Independent test of a good structureIndependent test of a good structureIndependent test of a good structureIndependent test of a good structure
Lahtinen et al 2007
It should be reused again and again eg Pechenga-Imandra-Varzuga
Beware of myths andBeware of myths and intellectual blindness
Manage heuristics and challenge dogma (it i th b i f l ti )(it is the basis of exploration)
No feeders, no funnelsNo feeders, no funnels: : the feeder model is the feeder model is missing the pointmissing the point
Naldrett
Adapted from Hoatson 2000
Myth: There are no world class examples of funnel shaped intrusion hosted Ni-Cu-PGE
Myth: conduits/pipes are notnecessarily feeders to large intrusions
depositsintrusionsThe ovoid is not the mouth of a large intrusion!
1. Breccia pipes1. Breccia pipes 2. Chonoliths or conduitsegeg AguablancaAguablanca, Carr Boyd, Carr Boyd eg Noril’sk, Nebo-Babel
Giant Mascot, BC
ChonolithChonolith definition:definition:
““a discordant igneous intrusion of irregular shape whicha discordant igneous intrusion of irregular shape whicha discordant igneous intrusion of irregular shape which a discordant igneous intrusion of irregular shape which has either been passively squeezed into a prehas either been passively squeezed into a pre--existing existing cavity or has actively forced apart the country rock. It’s cavity or has actively forced apart the country rock. It’s
relationship with the invaded country rock is very complexrelationship with the invaded country rock is very complexrelationship with the invaded country rock is very complex relationship with the invaded country rock is very complex and terms such as dyke, and terms such as dyke, laccolithlaccolith, etc., cannot be used, etc., cannot be used””
((TomkeieffTomkeieff, 1983, 1983). ).
Deposit characteristicsDeposit characteristics
<21 29-34 1-4 10-5029 34
>34 MgO wt%21-291-44-10
10 50
>50 sulfides wt%
I b i (di i i t f t t i b i )• Igneous breccias (discriminate from tectonic breccias)
• Hydromagmatic phases, pegmatoids, varied or taxitic texture –the volatile link 17% of the Siberian Traps is composed ofthe volatile link. 17% of the Siberian Traps is composed of pyroclastics
• Concentric crystallisation• Concentric crystallisation
•Well differentiated on scale of intrusive complex
Pipe-like bodies I: Plan
Jinchuan Kalatongke
Voisey’s Bay
Santa Rita
Aguablanca
2kmEagle
Nebo-BabelDouble Eagle
Nkomati
Noril’sk
TatiTalnakh
Pipe-like bodies II: cross section
Kharalakh Nebo-Babel
Kalatongke
200m
Nkomati
Eagle
Kabanga ?
Ban PhuchMirabela*
Pipes are only part of the intrusive complex!Pipes are only part of the intrusive complex!Pipes are only part of the intrusive complex!Pipes are only part of the intrusive complex!
WMN 44 WMN 34WMN 15WMN 44 WMN 34WMN 15
Babel ProspectBabel Prospect Nebo ProspectNebo ProspectEastEastWestWest
WMN 27WMN 21WMN 25WMN 25WMN 44WMN 18WMN 10WMN 12WMN 61WMN 34WMN 15WMN 27WMN 21WMN 25WMN 25WMN 44WMN 18WMN 10WMN 12WMN 61WMN 34WMN 15
? ? Lower Contact
R t S d
Massive Sulphides
Disseminated SulphidesDisseminated Sulphides
Nebo Mineralised Leucogabbronorite
Op enriched Gabbronorite
Babel Mineralised Gabbronorite
0 400
metres
800
Recent Sand
Granulite Dolerite
Cover Sequence
Opx enriched Gabbronorite
Gabbronorite
metresMarginal Breccia Zone Special Gabbronorite
Seat et al 2006
Sulfide are pooling/concentrating after crystallisation!Sulfide are pooling/concentrating after crystallisation!
Lightfoot and Zotov 2007Lightfoot et al 1999 Lightfoot and Zotov 2007
World class deposit rarely accumulate by gravitational settlingWorld class deposit rarely accumulate by gravitational settling
Clustering
Not all the elements of the cluster are mineralised. This will become important
-Emplacement level-Erosional level-Stress regime
How are deposits linked?How are deposits linked?ppWe don’t deliberately target or drill barren domainsWe don’t deliberately target or drill barren domains
Slide courtesy Dawn Evans-LamswoodSlide courtesy Dawn Evans-Lamswood
I th ti tI th ti tImage the entire ore system as Image the entire ore system as early as possibleearly as possibley py p
“World class Ni“World class Ni--CuCu--PGE deposits are the surface PGE deposits are the surface manifestation of crustal scale intrusive complexesmanifestation of crustal scale intrusive complexes””manifestation of crustal scale intrusive complexesmanifestation of crustal scale intrusive complexes
Noril’sk- Talnakh
Eagle
50km
Accommodation space Accommodation space dd t it iand and stress regimestress regime
90% of 90% of magmatismmagmatism in modern rifts and in modern rifts and transpressionaltranspressionalbasins is focussed in accommodation zonesbasins is focussed in accommodation zones
Regional Fault Regional Fault
Regional Fault
Local dyke swarm
Intrusive cluster
Intrusive cluster
Intrusive cluster
Local dyke swarm
Regional Faultt us e c uste
Regional Fault
Local dyke swarm
Regional Fault
Schematic Cross Section: Relationships Between Deposits, Structure, and Transfer of Silicate and Sulphide Magma
Upper Chamber(Eastern Deeps)
Sulphide Emplacement
Sulphide Trap
Ovoid and Mini‐Ovoid Zones
Lower Conduit
Conduit DykeConduit Dyke
Sulphide Entrainment
Lower Chamber
Crustal Extension Crustal Extension
Troctolite
Lower Chamber
(Western Deeps)
Massive Sulphide
Pre‐intrusivefaults/joints Geological relationships from
Li h f d N ld (1999)faults/joints
Syn‐emplacement faultLightfoot and Naldrett (1999); structural interpretation from Cruden et al., (2000)
ConclusionsConclusions• Invest in developing confidence in your targetsp g y g
• Understand the target context. It’s not arm wavering, its the difference between chasing any common garden deposit and world class.
• Getting out and hitting rocks is crucial but a poor target is a poor target. Improve your probability of success
• World class systems are clustered (it’s what makes them world class). Invest early in mapping the whole system and corridor (use
i t t l d i ) If f thi l it t l i l
• Chonoliths are not feeders to intrusions. They are parts of networks or
appropriate tools and spacing). If for nothing else it generate geological targets.
y pa corridor of intrusions which often include larger receptacles (layered intrusions) and passively emplaced dykes and sills.
•These ‘camps’ include a diversity of deposit styles reflecting the diversity of intrusive styles, assimilation histories, magma evolution, and evolving/fluctuating S solubility.
“World class Ni-Cu-PGE deposits are the surface manifestation of crustal scale intrusive complexes”
AcknowledgementsAcknowledgementsAcknowledgementsAcknowledgements
Colleagues at newgenco and UWAColleagues at newgenco and UWAFormer colleagues at WMC/BHPB for Former colleagues at WMC/BHPB for Former colleagues at WMC/BHPB for Former colleagues at WMC/BHPB for ‘the culture’‘the culture’Host of industry collaborators, Host of industry collaborators, y ,y ,colleagues, and studentscolleagues, and students