Skip to content

Leading Practice Mining Acts Review - Statutes Amendment Bill released | South Australia's Magnetite Strategy launched

Project name: Geophysical Cover Characterisations
Project leader: Rian Dutch
Project group: Philip Heath
Sarlae McAlpine (Geoscience Australia)
Karol Czarnota (Geoscience Australia)
Tristan Kemp (Geoscience Australia)
Program:Far West Discovery Program

Synopsis

The Coompana Province straddles the South Australian–Western Australian border in the state’s far west, located between the western Gawler Craton to the east, the Musgrave Province to the north and the Madura Province (Western Australia) to the west.

There has been little to no exploration that has directly targeted the bedrock of this region, largely because the depth to basement is poorly constrained and the geological characteristics and prospectivity of the region is poorly known.

As part of the UNCOVER initiative, Geoscience Australia (GA) and the Geological Survey of South Australia (GSSA) are committed to improving mineral exploration under cover. A key component of this effort is to improve mapping of the thickness and character of cover through geophysical imaging and prediction into data sparse areas.

In order to test cost-effective cover-thickness determinations, GA and GSSA trialed passive seismic, reflection seismic, magnetotelluric (MT) and micro-gravity methods over the Nullarbor Plain.

The objective of the Geophysical Cover Characterisation project is to assess the technical capability of the passive seismic, reflection seismic and magnetotelluric techniques to map cover-thickness over the Eucla region, particularly in areas of deep cover and karstic limestones, and to assess the micro-gravity technique to image large cavities within the karst.

This project is being undertaken in partnership with Geoscience Australia (a Division of the Commonwealth Department of Innovation and Science) under the National Collaboration Framework promoting State–Federal precompetitive geoscientific collaborative programs.

Background/Aims

The Coompana Province is completely covered by Neoproterozoic to Cenozoic sediments of the Officer, Denman, Bight and Eucla basins and there are no known records of outcropping basement.  Drilling records show that there are no more than 12 existing drill holes that intersect basement in the region, affirming the Coompana Province as a true geological and mineral exploration frontier.

Because of these factors the geology and mineral prospectivity of the region is largely unknown.

The aim of this project to initially conduct a passive seismic and MT experiment over six selected existing drill sites from the recent Mineral Systems Drilling Program completed in early 2016.

The data collected will be used to determine cover-thickness estimates and, if successful, additional passive seismic and MT surveys will be conducted over the proposed Coompana Drilling Project drill sites.

Reflection seismic and micro-gravity will also be trialed to assess the suitability of these techniques to determine cover thickness and/or image large cavities within the karst of the Nullarbor Limestone, which can then be avoided during drilling.

Key outcomes

  • Assess the suitability and effectiveness of the different geophysical techniques to image cover thickness, depth to basement and location of cavities in the Coompana Province to guide GSSA work programs and future exploration
  • New integrated drillhole and geophysically determined depth to basement map for the Coompana Region

Schedule for information and product delivery

DeliverableTime frame
New integrated drill hole and geophysically determined depth to basement map for the Coompana Region, SARIG map downloadDecember 2017
Co-badged Geoscience Australia record on methods and effectiveness of the different techniques, web download/SARIGDecember 2017
Summary article outlining the different techniques and results with recommendations for explorers, MESA Journal featureQ1 2018