department for manufacturing, innovation, trade, resources and energy mineral systems research in...
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Department for Manufacturing, Innovation, Trade, Resources and Energy
Mineral Systems Research in South Australia
Mineral Systems Workshop 1-3rd July 2013
Martin Fairclough & Simon van der Wielen
www.dmitre.sa.gov.au
Outline
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• Changing Role of the Geological Survey
• Mineral Systems and Mineral Potential Mapping Research in GSSA
• Examples• DETCRC Projects• GSSA Projects
• Issues
Changing Role of the Geological Survey
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• Driven by changes in the economic and political environment
• requirement to be more aligned to resource industry requirements (partly in response to changes in the industry)
• going beyond just precompetitive data, but actually focusing on value-adding to create more downstream exploration datasets (and concepts)
Mineral Systems & Mineral Potential Research
• Significant PIRSA (now DMITRE) involvement in pmd*CRC (including one on one projects) and post CRC projects with CSIRO
• Establishment of an “Exploration Geology Group” (EGG) in GSSA 2007 – produced a range of “key ingredients maps for commodities grouping deposit models)
• Chiropractic re-alignment of GSSA to form a dedicated Mineral Systems Team (2011). Process-driven approach
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Mineral Systems & Mineral Potential Research
• GSSA has been utlising the Five (or more) Questions approach for years – we just haven’t called it that!
• Very much a process-driven approach, particularly steering away from prescriptive ore-deposit model nomenclature (e.g IAEA), even though we still use the latter for communication purposes
• The Mineral Systems team focuses on the task of understanding the processes, and in conjunction with the Mapping and Modeling teams, translating the critical processes to mapable elements (or proxies)
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Case study - DETCRC
Emmie Bluff – reverse engineering an IOCG to understand that alteration system (targeting elements) and generating mapable criteria
Geochemical trends in IOCG alteration - new data from the Gawler Craton (Adrian Fabris)
Geochemical sampling protocol and initial results from the Emmie Bluff case study
Exploration strategies for IOCG mineral systems under deep cover (Simon van der Wielen)
IOCG exploration strategy and initial results Emmie Bluff case study
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Workflow
1x vertical exaggeration
60 km
9.8
km
N
Geological Surfaces
52 km
Emmie Bluff 3D Model
Emmie Bluff
8 – Mulgathing Complex
5 – Wallaroo Group
0 – DEM Surface
1 – Neoproterozoic
2 – Gairdner Dyke Swarm
4 – Gawler Range Volcanics
3 – Pandurra Formation
6 – Donington Suite
7 – Hutchinson Group
Listric Faults
Vertical Faults
10x vertical exaggeration
10 km
2 k
m
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Geochemistry Data
10 km
Emmie Bluff 3D Model
Emmie Bluff
Sericite
Hematite
Magnetite
Hematite – Magnetite
K-Feldspar
Albite
Sericite – Chlorite
Chlorite
10x vertical exaggeration
10 km
2 k
m
N
Hylogger Data
10 km
Emmie Bluff 3D Model
Emmie Bluff
2195 2225Sericite CompositionMuscovitic
Phengitic
10x vertical exaggeration
10 km
2 k
m
N
Alteration Voxet
10 km
Emmie Bluff 3D Model
Emmie Bluff
Sericite
Hematite
Magnetite
Hematite – Magnetite
K-Feldspar
Albite
Sericite – Chlorite
Chlorite
500 m x 500 m x 10 m cell size
Key Learnings from Emmie Bluff Case
Sample spacing for proposed pattern drilling program
Sampling strategy (unconformity vs sampling into the basement)
Has the current drilling tested the Emmie Bluff IOCG system?
Geochemical IOCG Prospectivity Index
Elements associated with IOCG mineral systems
Based on 10x crustal abundance
Can distinguish proximal from distal alteration
Independent of host lithology
See poster and Adrian Fabris in foyer
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Olympic Dam
Carapateena
MODELING THE MAPABLE ELEMENTS – PUTTING IT TOGETHERAlteration (DETCRC) and geophysical modeling of IOCG systems
S. van der Weilen,L. Katona and A. Fabris
Australian Copper Conference, June 18-19th 2013Martin Fairclough, Geological Survey of SA
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New Data Collection To Further Test Modeling Concepts
Australian Copper Conference, June 18-19th 2013Martin Fairclough, Geological Survey of SA
Case study 2
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All IOCGs in South Australia are elevated in uranium, as are large parts of the surrounding host rocks (“the reservoir”).
No significant elevated uranium older than ca. 1580-1590 Ma
However, considerable examples of anomalous (some economic) uranium throughout younger rocks (such as Beverley, possibly active very recently)
So the fluid pathways and drivers are working well also
What about other traps? “uncomformity-related” just to give one possibility a name.
Case study 2
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All IOCGs in South Australia are elevated in uranium, as are large parts of the surrounding host rocks (“the reservoir”).
No significant elevated uranium older than ca. 1580-1590 Ma
However, considerable examples of anomalous (some economic) uranium throughout younger rocks (such as Beverley, possible active very recently)
So the fluid pathways and drivers are working well
What about other traps? “uncomformity-related” just to give one possibility a name. So – first understand the processes.
Case study 2 – Athabasca and Cariewerloo
Case study 2 – Athabasca and Cariewerloo
Multi-parameter lithostratigraphic logging
Hyperspectral logging
Magneticdepth to basement Geophysical
Interpretation
AEM survey
Adobe 3D pdf
Case study 2 – Athabasca and Cariewerloo
And numerous other projects
........... That are not explicitly “Mineral Systems Approach” but nevertheless follow the same philosophy
In fact, virtually all GSSA projects in some form have the MSP goal in mind, as well as mineral potential modeling and undiscovered resource endowment modeling
.........but still some issues to resolve on data standards and delivery.
Issues and discussion
Standard Mineral Systems approach:
does not adequately address post-depositional modifications (maybe duration of events should be extended to multiple events) (Jaireth)
this is related to the preservation issues
Does not easily encompass co-existing deposit types in same mineral system(s) (Huston). e.g Gawler Craton IOCG, skarn, mesothermal gold, epithermal gold/silver and porphyries(?)
Critical dataset collection should be prioritised by understanding critical processes and subsequently, targeting/mapable elements – not dumb precompetitive data collection to fill gaps.
Only an understanding of the processes will determine scale-dependency and subsequent mapable criteria (even for Geological Survey’s precompetitive data collection)
Issues and discussion