Transcript presentation.

Adding value in gold exploration
Neil Phillips
University of Melbourne &
Phillipsgold P/L, Australia
30+th SirJulius Wernher Memorial Lecture
Institute of Materials, Minerals and Mining
28 October 2010
London UK
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Gold supply shortfall
Discoveries
Discovery – why it matters
Exploration in the future
Repeated discoveries – learning from these.
Supply and demand for gold
Discover gold
Mine gold
Sell gold to meet demand
Supply and demand for gold
Discover gold
Mine gold
2500t pa
Sell gold to meet demand
4000t pa
Supply and demand for gold
Discover gold
Central banks
Mine gold
Sell gold to meet demand
Individuals hoarding
Supply and demand for gold
Discover gold
Central banks 30000
Mine gold 2500
Sell gold to meet demand 4000
Individuals hoarding ~30000
New Generation Gold Conference
• 2009, 2007, 2005, 2003.
• Also previously 2001, 1999, 1997, 1995.
Recent discoveries - conclusions
• Mature gold provinces
– Archaean of Australia, Canada
• Established gold regions
– Ghana
• Less-traditional gold areas (wrt 20th century)
– Mali, Peru, China.
Recent discoveries - conclusions
• Decreasing dominance of gold-only
• Increasing role of gold-plus
– Copper-gold
– Larger tonnage
– Longer life (50-100 years)
– Lower gold grade.
Witwatersrand 1886 and 1951
1886:
Rand (George Harrison)
Klerksdorp
1930s: Carletonville
1940s: Welkom
1951: Evander.
Witwatersrand 1951 to 2010
1951 to 2010: no new goldfields.
Gold production: 1970 - 2010
South Africa
World
Future exploration focus
Future exploration focus
Lots of dollars, projects, drilling
or
Raise discovery rate (σ)
Discovery rate (σ)
Adds real value
σ
Ounces discovered per exploration dollar
Future exploration focus
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Country?
Technique?
Idea?
Who?
• How to add value.
Which country?
Appetite for risk
Particular knowledge or expertise
Special opportunity
geology or commercial deal
But not everywhere.
What techniques?
Classic success stories
- Ground magnetics in Witwatersrand
- EM in Noranda, Canada (Cu, Zn, Au)
- Regolith methods, Western Australia.
What ideas? – Gold genesis
Syngenetic on seafloor
- Follow horizons, stratigraphy
- Only for Cu-Pb-Zn-Ag-Au (VMS).
What ideas? – Gold genesis
Epigenetic (after rocks have formed)
- Host rocks – mechanical & chemical
- Alteration – CO2+K+H2S
- Orogenic – role of structural geology
Hogan 2004
New ideas – Gold genesis
Hydrothermal gold deposits do not
form at 700oC
- Continuum model is inappropriate.
Future exploration focus – Who?
Discovery is a rare event
Within exploration it is atypical
Future exploration focus – Who?
Rarely is a discovery so obvious that
everyone can ‘see it’, and agrees that
it should be drilled.
Future exploration focus – Who?
It follows then that ..
- Harmonious group, consensus
- Large collaborative team
- May not correlate with discovery.
Welkom Goldfield
5 km
Reproduced from Antrobus (1986)
Hydrothermal model
Wits formation
• Since 1900 two ideas
• Placer dominates exploration
• - no source, no universal sorting mechanism
Welkom Goldfield
No gold in source area
No special sedimentary sorting
5 km
Reproduced from Antrobus (1986)
Witwatersrand gold - ideas
A winner was selected
Commitment to idea, not to discovery
No alternatives.
What would Wernher do?
Sir Julius Wernher
• Rand goldfields of Johannesburg
• Wernher, Beit and Co.
• Imperial College
Development of Yandal gold
1894 Alluvial gold
1987 Mt McClure
Yandal
Perth
Yandal story – field work
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Fe-rich host rocks
Structural style
Carbonate, mica, pyrite alteration
Quartz veining
Anomalous gold
Akin to prospective gold areas.
Minsaco Resources 1986
Development of Yandal gold
1894 Alluvial gold
1987 Mt McClure
1992 Bronzewing
1993 Jundee, Nimary
1996 Jundee deeps- Barton, Centenary
1999 Thunderbox
Future exploration focus – Who?
Smart, motivated
Directed – we are here to make a
discovery.
Future exploration focus – Who?
Line-of-sight (priorities).
Future exploration focus – Who?
Confidentiality
Confidentiality?
“Good!
I will use your idea in my next talk”.
Don’t worry about someone else
stealing your idea; if it is any good
you will have to ram it down their
throat.
(Kerr Wan-Tass, 1997)
Conclusion
• Discovery – the magic may lie in the people.