North West Queensland Mineral and Energy Province study
July 2009 to December 2010
While North West Queensland is recognised as a world-class, mature exploration destination, vast tracts of prospective ground remain under-explored because of surficial cover. The region contains an estimated 75% of Queensland's total metalliferous resources such as copper, silver, lead and zinc. It includes, but is not limited to, the Mount Isa Province which has a long and proven record of mineral endowment. The region also has significant energy resource potential including renewable (geothermal) and non-traditional (tight shale) resources.
The North West Queensland Mineral and Energy Province study (NWQMEPS) has improved geological understanding through geological mapping and geophysical data acquisition programs, under the Queensland Government's Smart Exploration and Smart Mining Initiatives. The NWQMEPS is a joint initiative of Minerals Geoscience, Energy Geoscience and the Greenfields Prospectivity Unit.
Figure 1: Extent of the NWQMEPS
The objective of the study was to increase geological understanding of mineral and energy resource potential in the highly prospective North West Queensland region, in order to stimulate investor interest and effectively focus exploration activity.
The study involved:
- updating the first edition of the NWQMEPS using new geological, geophysical and geochronology data
- conducting a regional analysis which integrated geological and potential field data to develop a comprehensive geodynamic and architectural framework
- providing a 3D model to improve understanding of geology at depth and in under-explored greenfields regions with shallow cover
- examining likely controls on mineralisation and developing new mineralisation models
- providing regional-scale resource evaluation studies of specific deposit styles
- investigating camp-scale alteration footprints by linking surface and down hole spectral data to enable 3D imagery of surface and subsurface mineralogy and chemistry for better vectoring of mineralising systems
- producing material to promote the prospectivity of North West Queensland at national and overseas conferences in order to attract explorers to the region and contribute to regional planning
- providing in-depth geological information to support exploration in North West Queensland.
Due to considerable uncertainty surrounding the geodynamic setting for North West Queensland, an Isa-centric holistic framework was developed to recognise the continental-scale impact of Proterozoic plate interactions and their expression as specific deformation events.
Figure 2: Eastern Australian Proterozoic terranes
Given over 80% of the study area was concealed by cover, potential field and electrical datasets were integrated with geological and remotely sensed data to provide improved interpretation of subsurface geology. The study included new magnetotelluric and seismic data, and depth to basement modelling to provide 3D models of the region integrating new data with updated stratigraphic interpretations and results of recent geochronology.
Figure 3: Mount Isa inlier fault network showing background TMI, magnetotelluric and deep seismic transects
Regional mineral prospectivity analysis
Comprehensive, minerals-system based models were developed to define characteristics that could be used to assess the potential for further mineralisation, particularly undercover. These included:
- structurally-controlled epigenetic Iron Oxide-Cu-Au (IOCG) deposits
- Ag-Pb-Zn in high-grade metamorphic terranes in the east of the region
- strata bound sediment-hosted Zn-Pb-Ag
- structurally-controlled epigenetic Cu±Au deposits in the west of the region.
Camp and deposit alteration systems
Improved understanding of the mineral systems that result in metallic mineral deposition will help explorers re-evaluate terrain for new opportunities. New analytical techniques such as HyLoggerTM for down hole spectral analyses, and portable XRF analyses of geochemistry of surface and subsurface samples can better characterise mineralisation.
The HyLoggerTM was used to scan the core from exploration drillholes in the region. The combination of airborne hyperspectral and HyLoggerTM data delivered a significant enhancement by allowing surface mineral and chemistry mapping to be extended into the subsurface.
Test areas for demonstration projects were investigated in the Cloncurry IOCG belt. Several sites lie within the footprint of recent airborne hyperspectral surveys, so both surface and core-derived HyLoggerTM subsurface spectral data can be compared. The Mount Elliott-Mount Dore-Selwyn corridor was chosen as the site for an initial detailed analysis to provide training data for regional numerical analysis of Cu±Au±Mo-Re potential.
Figure 4: Drillholes being used in the Kalman HyLoggerTM project
The North-West Queensland Mineral and Energy Province report and data package including the NWQMEP 3D model can be downloaded from QDEX Data.