The purpose of the Predictive Mineral Discovery CRC (pmd*CRC) is to generate a fundamental shift in exploration practice and cost-effectiveness by developing a vastly improved understanding of mineralising processes and a four dimensional understanding of the evolution of the geology of mineralised terranes.

The pmd*CRC was conceived by industry in partnership with the geological research community to focus research on issued that are of critical importance to ore discovery. The long-term objectives are to:

• Contribute to the resolution of the key areas of uncertainty in current models for the formation of major economic mineral deposit types within mineralised terrenes that have a high exploration priority.
• Build 3D and 4D images and histories of well known mineralised systems.
• Create a computational environment to simulate the 4D evolution of mineral systems with the goal of developing predictive capabilities for the location and quality of superior ore deposits.
• Create a commercial computational, visualisation and communications environment to allow companies to manage exploration and operational activities more efficiently.
• Transfer these concepts, skills and technologies into the mineral exploration industry to assure a long-term competitive advantage to the industry.

The major projects being undertaken by the pmd*CRC with the NSW Department of Primary Industries are:

Understanding and predicting the location of the Broken Hill ore deposit.

This project is in the concluding phases in investigating two areas that may lead to new insights at Broken Hill. One was to clarify the timing of early high-grade metamorphic events and the second was to test new applications of existing 3D software in conjunction with field mapping.

A variety of geochronology techniques have been utilised at Broken Hill such as the Lu-Hf laser ablation technique to garnets that can help identify the prograde timing of metamorphism. This has led to a better understanding of the temporal and physical link between metamorphism and the origin of Broken Hill Type deposits. Other techniques such as Sm-Nd of monazites record the beginning of cooling from the very high temperatures to which the area was subjected.

Focused field-based work was completed to better understand the integration of stratigraphy, structure and metamorphism through application of modelling software and relating this to field mapping and structural observations to enhance or change the current regional 3D geological model.

Crustral architecture, 3D geological map and mineralisation in Tasmanides of eastern Australia

The aims of this project are to construct a seamless 3D map of the Tasmanides (that is, a regionally consistent structural, stratigraphic and intrusion architecture of the Tasmanides Orogen) to understand the fundamental controls on location of major ore deposits (gold and base metals) and to assist the mineral exploration industry to predict and discover new world class ore bodies in Southeast Australia.

In Year 1 (2004-05), the project involved data compilation, geophysical processing and geological interpretation. A large volume of public domain geological, geophysical, geochemical and mineral occurrence data were assembled into a coherent 2D GIS (MapInfo) and 3D platform (FracSIS). Geophysical processing involved constraining the positions and intensity of potential field gradients (“worms”) and geologically constrained inversions of selected regions. Through collaboration with partner (NSW DPI, Geological Survey of Victoria, Geoscience Australia and the University of Melbourne) institutions, an interpretation of these GIS layers focussed on the architecture of major faults, intrusions and regional geology. The spatial distribution of mineral deposits, categorised by major commodity, deposit style and resource size, were merged within the interpreted geological architecture.

In Years 2 and 3 (2005-07) the work continues to focus on architecture with constructing the 3D geometry of parts of the Tasmanides. The methodology involves construction of geological cross sections, with constraints from geophysical modelling (3DGeomodeller; forward modelling of the cross sections; and 3D inversions and seismic data. Revisions to the time-space correlation charts will be made accordingly and an analysis of controls on major mineral systems incorporated into the 3D model (focusing on the 3 key questions of fluid reservoirs, pathways & drivers, and migration/deposition) will be undertaken.

Thomson-Lachlan Seismic survey

The objective of the project was to use high resolution deep seismic reflection data to help solve one of the key mysteries of geology in far north-western New South Wales, by defining the nature (and location) of the east-west boundary between the Lachlan and Thomson orogens. The data will also help highlight for the mining industry a new mineral province in this poorly known part of the State, with potential for gold and base metal deposits north and south of the boundary. It will also lead to a better understanding the petroleum systems of the Darling and Eromanga Basins by providing data on thermal maturity, migration pathways and trap developments.

The three seismic lines are within a 100 km radius of Tilpa, between Bourke and Wilcannia. They extend from the southern part of the Thomson Orogen into the Lachlan Orogen where it covers the northern part of the Darling Basin – the Nelyambo Trough and Mt Jack High.

The seismic measurements were acquired with three vibroseis trucks, was carried out by the Australian National Seismic Imaging Resource (ANSIR) under the supervision of pmd*CRC. A Cultural Heritage Survey was successfully completed by a recognised archaeologist.

A Review of Environmental Factors (REF) was also successfully completed to ensure that the work program had a low impact on the environment and to ensure correct procedures were employed to minimise disturbance. The area over which a seismic survey is acquired is small and every care was taken not to disturb the surface layer and the majority of the seismic lines were along existing shire roads and station tracks.

Processing will be completed by the pmd*CRC and interpretation to be jointly completed by staff from DPI-MR, Geoscience Australia and the pmd*CRC.

Cobar Region 3D Geology Project

The project is a collaborative project between NSW DPI, pmd*CRC and mineral exploration companies in the Industry Consortium. The project aims are to identify potential new mineral targets in “difficult-to-explore” areas in the Cobar Region. There is now a need to explore using 3D interpretations and employ approaches which involve a clear understanding of how the 3D geological architecture controls the locations of ore deposits. The project will utilise state of the art 3D computerised geological modelling technology to construct an integrated 3D model that will build on the 2D data collated by NSW DPI and the companies making up the Industry Consortium. The 3D model will provide a rigorous framework that will identify gaps in present geological understanding and underpin future long term exploration in the region. This in turn is expected to create new opportunities for mineral discoveries in the Cobar region by the Industry Consortium and other explorers by enabling the development of more effective targeting strategies. It is anticipated that the project outcomes will also contribute to a fundamental shift in exploration practice and cost-effectiveness in the region.