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Presentation to AIG Melbourne 7 July 2015
Seismic ReflectionDeep and meaningful data for mineral exploration,
hydrogeology and geotechGreg Turner
Presentation to AIG Melbourne 7 July 2015
Outline
• Role in hydrocarbon exploration• Why has the mineral industry been slow to
adopt?• Opportunities• Case histories• Derisking the application of seismic• Summary
Presentation to AIG Melbourne 7 July 2015
Minerals vs hydrocarbons
Used ubiquitously in hydrocarbon industriesWHY?• Can investigate to large depths• Provides continuous maps of layer
boundaries and structures• High Resolution• Maintains resolution with depth
Used rarely in minerals industryWHY NOT?• Lack of effectiveness• Lack of need• Cost
Presentation to AIG Melbourne 7 July 2015
1 Lack of Effectiveness
Hard rock seismic is hard!Complex 3D geometry and high velocity rocks requiresignificant adaptions to the technology which hasevolved in soft rock environments
Much progress has been made• More channels → higher fold• Customised processing• Interpretation experience
Slow to Adopt and Adapt - WHY?
Presentation to AIG Melbourne 7 July 2015
2 Lack of Need
Drilling program to 200m:$15K/hole
Drilling program to 400m:$60K/hole
Drilling program to 1000m: $200K/hole
Typically for seismic:
Depth ► Source and Receiver ► Costspacing
Slow to Adopt and Adapt - WHY?
Presentation to AIG Melbourne 7 July 2015
3 Cost
Cost has massively reduced in last 20 years due to:• Chinese manufacturing• Increased computing powerSeismic is still expensive compared with other geophysical methods
2D ≈$10K/km 3D ≈$200K/sq kmBUT provides different information• Can investigate to large depths• Provides continuous maps of layer boundaries and structures• High Resolution• Maintains resolution with depth
Slow to Adopt and Adapt - WHY?
Presentation to AIG Melbourne 7 July 2015
The opportunity
• Faster screening around initial discovery
• Better conceptual understanding of geology andmineralisation
Optimise infrastructure capacity andplacement
More cost effective brownfields exploration
• Better mapping of structures for mine planningand mine safety
Presentation to AIG Melbourne 7 July 2015
Resource growth over time
Presentation to AIG Melbourne 7 July 2015
Mt Marion
GGrove
KanownaKambalda
Sunrise DamWallaby
Argyle
Ranger
Century
Cannington
Beverley
Marsden
2D Survey
3D SurveyLeinsterAgnew
CSM, IGO, LanfranchiForestania
Jundee
Telfer
Vulcan
McArthur
Tanami
Plutonic
Ballarat
Pilbara
DeGrussa
Paulsens
Tropicana
Pajingo
Cracow
CarrapateenaProminent
Hill
Hillside
Bullabulling
Rosebery
Australian minerals seismic surveys
Tennant Ck
Presentation to AIG Melbourne 7 July 2015
Case history – Neves CorvoCopper–Zinc
Presentation to AIG Melbourne 7 July 2015
Obrien keyslides extract_003Obrien keyslides extract_003
6 known orebodies
Are there any more?Prospective geology
700m+
Presentation to AIG Melbourne 7 July 2015
Obrien keyslides extract_002
Presentation to AIG Melbourne 7 July 2015
3D survey grid over mine
Presentation to AIG Melbourne 7 July 2015
Presentation to AIG Melbourne 7 July 2015
Presentation to AIG Melbourne 7 July 2015
"A high-resolution 3D seismic survey has now beencompleted over a 21 square kilometer areasurrounding the Neves-Corvo mine. Preliminary resultshave clearly imaged the major Semblana deposit,verifying the effectiveness of this new tool in thesearch for blind massive sulphide deposits"Lundin Mining news release to theToronto stock exchange. July 21, 2011
Presentation to AIG Melbourne 7 July 2015
Case Study 1: Cracow– Locating structures hosting mineralised veins
Back Creek Sedimentsoverlie western endof line
Presentation to AIG Melbourne 7 July 2015
From Corbett 2002
Epithermal systems
chaotic,sub-verticalveins
alteration
Presentation to AIG Melbourne 7 July 2015
AI1 AI1
AI2 AI2
AI2 > AI1 AI2 >> AI1
AlteredFragmentals
AlteredAndesiteLava
Fragmentals
Andesite Lava
SeismicProcessing
AGC Processing Partially Preserved AmplitudeProcessing
Preserved amplitude processing
Presentation to AIG Melbourne 7 July 2015
Cracow – 2D seismic
8km
2km
Presentation to AIG Melbourne 7 July 2015
Cracow – 2D seismic interp
8km
2km1
2
3
Presentation to AIG Melbourne 7 July 2015
Cracow – recent drilling
Presentation to AIG Melbourne 7 July 2015
Cracow – recent drilling
Presentation to AIG Melbourne 7 July 2015
Cracow - Vertical Section from3D Seismic Cube
Preserved Amplitude Processing
1 km
OverlyingVolcanics
InterbeddedAndesitic Lavasand Fragmentals
Increasingalteration
Reflections due to acoustic impedance (density*velocity) change across boundarybetween fragmentals and lavas
Presentation to AIG Melbourne 7 July 2015
Vertical Section from 3D Seismic CubeEpithermal Gold Vein System
1 km
Location of gm-m intersections±50 m either side of section
Mineralised vein. Faultedoffset, clay alteration
Presentation to AIG Melbourne 7 July 2015
Depth slice at 484m
(Adapted fromKlein2014)
Horizontal section from3D seismic cube
Presentation to AIG Melbourne 7 July 2015
Horizontal section from3D seismic cube
Depth slice at 484mGrey lines represent faults, some of whichcorrespond to the location of known faultsand epithermal orebodies
(Reproduced fromKlein2014)
Presentation to AIG Melbourne 7 July 2015
"Significantly the 3D seismic survey maps the location of bothknown fault/vein systems as well as a significant number of otherfaults likely to host epithermal veins. This is potentially abreakthrough technology to map complex fault and vein systemsand together with other geologic parameters directly target partsof the fault likely to host gold mineralisation.
The current and planned drill programmes are the critical test inenabling Evolution to compress the timeframes for newdiscoveries around Pajingo and Cracow through the use of 3Dseismic."
Evolution Mining Quarterly Report,30 Sep 2014
Presentation to AIG Melbourne 7 July 2015
Geotech tool– pit wall stability, positioning of shafts, raise bores
Presentation to AIG Melbourne 7 July 2015
Hydrogeological tool– trace acquifers, identify connectivity
From Martin et al 2013
Presentation to AIG Melbourne 7 July 2015
Hydrogeological tool– map internal structure within acquifer
From Martin et al 2013
Presentation to AIG Melbourne 7 July 2015
Is seismic suitable at your site?
Noise Tests,Design Optimisation
Rock PropertyMeasurements
3D Seismic Survey
Vertical SeismicProfiling,Full wave sonic,Source testing,2D seismic
Synthetic Modeling
How do we de-risk aseismic survey?
Presentation to AIG Melbourne 7 July 2015
Rock property measurements
• Measure transit time through core,half core or hand specimen
• Need flat ends• Multiple samples per rock unit
Presentation to AIG Melbourne 7 July 2015
Synthetic modelling
• Wide scattering
• Forward modelling of possiblegeological scenarios is crucialfor survey planning
• 3D effectsImplications for targeting
• Assess what features arepotentially resolvable
Presentation to AIG Melbourne 7 July 2015
Velocity DensityAcousticImpedance
Strongreflectorsin VSPdata
Sonic anddensity logs
Reflector
Reflector
Reflector
Reflector
Reflector
Reflector
Presentation to AIG Melbourne 7 July 2015
VSP
VSP’s provide the macro-scalelinkage betweengeological/petrophysicalvariations and the bulk in-situresponse measured usingsurface seismic reflectiontechniques
reflections
direct wave
dept
h
time
Presentation to AIG Melbourne 7 July 2015
Strongreflectorsin VSPdata
Reflector
Reflector
Reflector
Reflector
Reflector
Reflector
VSP
Presentation to AIG Melbourne 7 July 2015
Open file data sets
Opportunity to re-process based on specific objectives
Presentation to AIG Melbourne 7 July 2015
Summary
TypicalSolution
(Drilling)
Sweet SpotBrownfieldExploration
> ~300m
SeismicSolution
(Seismic +Drilling)
• Data in only 1D.• Slow: 1 month to drill 1km.• Costly: $250K per km.
• Detect structures & alteration.• Directly detect some
mineralisation styles• Cost competitive @ $250K/km2
• Rapid results.• Low environmental impact• Faster 3D targeting of drilling
Presentation to AIG Melbourne 7 July 2015
Steep dips?
• We did a 2D seismic line at Pegasus in the Kundanabelt, and the historic view is that in very steeply dippingstructures you don’t get a lot of information, but the earlysigns from the 2D seismic at Kundana will probably leadus to do a 3D as it very very clearly showed thestructures and enhanced the targets that they aredrilling”.
Stuart Tonkin Northern Star Resources COORIU Explorers Conference, Fremantle February 2015
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