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

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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

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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