Coompana Drilling Program

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A location map showing eight completed drill holes in the Coompana province of South Australia

The Coompana Province, located between the Gawler Craton to the east, the Musgrave Province to the north and the Madura Province to the west, straddles the South Australian-Western Australian border along Australia’s southern coastline. The basement geology and mineral prospectivity of this vast region is poorly understood because there are no known rock exposures due to extensive Neoproterozoic to Cenozoic cover sediments of the Officer, Denman, Bight and Eucla basins. Very little exploration drilling to test the hidden basement rocks of this region has ever been undertaken.

Progress

Drill targets were carefully designed to test various geophysical domains interpreted from recently acquired Coompana Magnetic and Radiometric Survey and the PACE Copper Coompana Gravity Survey.

Prior to commencement of the drilling program, Geoscience Australia undertook a mixture of pre-drilling geophysical surveys, including magnetotelluric, seismic reflection and passive seismic at historical and proposed drill sites with highest priority. The objective of the geophysical surveys was to characterise the thickness and nature of cover at each drill site to assist with drill program planning.

The geoscience research drilling was successfully completed at eight drill sites between early April and mid-September 2017. More than 1500 m of new oriented HQ3 diamond core samples of the Coompana crystalline basement were collected. Downhole gamma and temperature logs were acquired in each of the drill holes to constrain the stratigraphy of the cover units and thermal structure of the Coompana basement rocks.

Outputs

  • Magnetotelluric and seismic reflection pre-drilling geophysical data is available on the Geoscience Australia website.
  • Geophysical data packages are accompanied by GA Records detailing the data acquisition, processing and interpretation methodologies for estimating cover thickness.
  • Preliminary field-data reports that summarise the drill hole completion data, field stratigraphic and lithological logs and down hole geophysical data are available via the South Australian Resources Information Gateway (SARIG).
  • Geological Survey of South Australia (GSSA) geoscientists are in the process of comprehensively characterising the Coompana core samples at the South Australian Drill Core Reference Library. All Coompana drill core has been scanned using the HyLogger™ and Minalyze XRF scanning instruments and structural, geochemical, mineralogical, petrophysical and geochronological analysis is underway. The new analytical data will be used to build a new model of the geological evolution of the Coompana Province which will provide a framework for understanding the mineral potential of the region.
  • A new basement geology map of the Coompana Province and an Explorers guide to the Coompana Province will be released via SARIG in March 2018.
  • The Coompana Drilling Program results and analysis will be released to industry at a workshop to be held in Adelaide in March 2018.
  • A synthesis report on the results of the drilling program and subsequent analysis of core samples will be available for download via SARIG in June 2018.

Collaborations

The Geological Survey of South Australia (GSSA), Department of the Premier and Cabinet in partnership with Geoscience Australia completed the $3 million regional pre-competitive geoscience research drilling program. The collaborative program was jointly funded by South Australia’s PACE Copper Initiative and the Commonwealth Government’s Exploring for the Future program. The drilling contract was awarded to the South Australian based Boart Longyear Australia Pty Ltd (Boart Longyear) via an open competitive tender process.

Boart Longyear drill rig used to retrieve core samples in Coompana, South Australia