Targeted 3D district-scale prospectivity studies are aimed at attracting exploration investment into covered greenfields terranes by providing robust models to improve targeting outcomes.
The areas selected for assessment provide a mix of exposed and covered terranes designed to extrapolate knowledge of mineralisation processes into adjacent subsurface areas.
Figure 1: Location of district-scale 3D prospectivity studies
The studies are based on a process of producing 3D discretised volume models (voxets) of the project areas using GoCAD model-building software. Each discrete building block (voxel) is assigned a set of rock property values including lithology, density, magnetic susceptibility and sometimes conductivity. This value is then used to form a Common Earth Model (CEM). Geophysical properties are assigned from the results of high-resolution geophysical inversions using a range of software (such as VPmg, UBC and Geomodeller) applied to geological volume models constructed in-house.
CEMs are used for a weights-of-evidence style analysis based on key targeting criteria for important mineralisation styles unique to each project area. The mineral potential modelling process defines discrete areas of higher mineralisation potential predicted to exist at a range of depths throughout the project area, which can be used as a guide for tenement selection or for drill targeting by greenfields explorers.
Figure 2: 3D geological model of the Quamby area (left) and resultant 3D mineral potential model (right)
Mount Dore project (2011)
The prospectivity study assessment technique was first applied to define IOCG prospectivity in the Mount Isa Eastern Succession, and the study formed a key part of the North-West Queensland Mineral and Energy Province study released in 2011.
Quamby project (2011–13)
The Quamby Project lies to the north of Mount Dore, covering an area 95km long by 80km wide. The area includes the major operating Ernest Henry Cu-Au mine, as well as significant Cu-Au projects such as E1/Mount Margaret, Rocklands and Roseby, and the Dugald River Ag-Pb-Zn deposit. Targets include structurally-controlled epigenetic Cu±Au±iron and sediment hosted copper (shale hosted or supergene enriched) in the oxide zone.
Final results for the project were released in August 2013 as 3D mineral potential of the Quamby area in the Queensland Minerals and Energy Review Series which can be ordered from the Geological Survey of Queensland. The Quamby project report is also available as a free download from QDEX Reports. The data is available in QDEX Data.