Pre-competitive targeting of mineral systems

Geoscience Australia - Increasing attractiveness of Australia for investors in mineral exploration

From simple beginnings as a survey office for public lands in 1901, Geoscience Australia (by its current name) developed throughout the 1950s and beyond, into a geological and geophysical mapping organisation, supporting the nation’s informed mineral exploration industry.

Today, Geoscience Australia fills a much increased role. As well as supporting the development of the Australian minerals, and Oil and Gas industries, the organisation meets the Australian Government's geosciences requirements to maintain a knowledge-base and expert advisors in diverse fields such as: Natural hazards including tsunamis and earthquakes, the impacts of climate change, groundwater research, marine and coastal research, carbon capture and storage, vegetation monitoring, Earth observations from space, as well as monitoring Australia’s large marine jurisdiction.

Fundamental to all these responsibilities is their charter to convey geological and geophysical data to the general public in order to promote the resources and environmental services industries in Australia, and hence promote associated investment by the local and international private sector.

New discoveries of the 21st Century will be under cover and harder to find - And further challenges too will be due to reduced budgets and environment restrictions

The reality of shrinking non-renewable resources, and a more technically and commercially challenged industry sector are issues to overcome in the 21st Century. For example, major minerals reserves of the past were relatively easy to discover, but the next generation of resources will require exploration deeper undercover and with more carefully constructed exploration models, than ever before. Increasingly concerning environmental issues also present a range of challenges affecting Geoscience Australia today.

Australia is, and should continue to be, seen as a leader in the management of pre-competitive geological and geophysical data and interpretative products. Geoscience Australia makes such products available to the resources exploration sector and hence fulfills its role of fostering a globally recognised resources industry, whilst attracting strong associated investment. Effective communication and excellent project linkages between Geoscience Australia and its stakeholders is critical to the success of this process.

Another issue affecting the capacity of Geoscience Australia to perform its role, is that other bureaus and agencies compete for a finite pool of taxpayer-based funding which is administered by the Federal government. Additionally Australia is a wide land – so often data sets are sparse by design simply to spread a programme's budget as far as possible. This in itself creates further challenges for interpretation of our legacy and new data sets. 

Be smart; Integrate varied high quality data sets; Use best available technology and software 

Therefore, we need to be smart, and use best quality data combined with best available technology. We also need to use high level communication skills and imaging to communicate opportunity and results to a range of recipients from explorers to government ministers. Only this way can we both attract investment and gain the approval of taxpayer representatives and thus compete for Federal funding.

Search for a giant copper porphyry system in eastern Australia

Australia’s federal and state geological survey organisations are co-operating in an ongoing search for a giant Copper Porphyry system. We all know the story, the easy-to-find copper Porphyry systems are all discovered now. What next? Look undercover! Think big! and Look for:

  • Mega-scale structural trends with vestiges of ancient volcanic arcs
  • Spherical magnetic anomalies
  • Potassic (K) anomalies in radiometric surveys
  • Petrology of porphyry systems in neighbouring regions (could be 100s of km away!)
  
Stavely region of Victoria Left: Magnetic intensity grid reduced to the pole (50 m cells). Right: Initial GeoModeller model of the Stavely Project constrained by 14 new stratigraphic drill holes, surface mapping, interpretations from seismic, gravity and magnetics (courtesy of Goodwin and McAlpine, 2015. Geoscience Australia, unclassified workshop paper).

Adopting a mineral systems-based approach led Australia’s premier science organizations to hone-in on Mt Stavely in western Victoria, Australia – as a prospective region for discovery of a giant copper porphyry system. In the process, software by Intrepid Geophysics was used in the orchestration of this large project, bringing together diverse data, and facilitating advanced interpretation of potential fields data for:

  • Geology model-building from primary data
  • Validation against gravity and magnetics data (forward and inverse modelling)
Future project work will also include:
  • Auto-structural interpretation (multi-scale edge-detection)
  • Processing and gridding potential fields data (including radiometrics)
A rigorous approach to minerals exploration including 3D geological and geophysical modelling is showing early promise for a successful outcome in the search for a copper porphyry system.

Early drilling has revealed mineralisation of generally propylitic grade porphyry dykes with some potassic grade mineralisation (±phyllic ) about 0.2-0.3% Cu, intruding less mineralised (or barren) volcanic host.

All manner of exploration workflows can be implemented in the complementary software suites ‘INTREPID’ and ‘GeoModeller’ developed by Intrepid Geophysics in Brighton, Australia.

For more information about software products please contact sales@intrepid-geophysics.com

 

Porphyry zonation as vectors to mineralisation (Figure after David Taylor, Geological Survey of Victoria, 2015, unclassified conference paper).

 

For more information about the Stavely Project see:

http://www.uncoverminerals.org.au

http://www.energyandresources.vic.gov.au/earth-resources/geology-of-victoria/gsv-projects/the-stavely-project

 

 

 

 

 

 

 

 

Next

 

Previous 

Back to Blogs