Monday 17 October 2022

MinEx CRC, in collaboration with the Geological Survey of South Australia (GSSA), has successfully completed a 24-hole, scientific drilling campaign of the Delamerian Orogen in eastern South Australia, unlocking the region’s mineral potential and trialing more environmentally friendly, cost-saving drilling technology.

The campaign was the second round of the world-first National Drilling Initiative (NDI), designed to understand the evolution of the Australian continent, provide clues about where to search for new mineral deposits and bring forward the next generation of mineral exploration technology.

In collaboration with Geoscience Australia and geological survey organisations in every state and territory, the NDI is delivering a seven-year program with multiple drilling campaigns across Australia.

The Delamerian NDI campaign has confirmed that the 500-million-year-old basement rocks buried beneath sedimentary sequences of the Murray Basin were formed in a geological setting conducive to the formation of base and precious metal mineral deposits.

MinEx CRC CEO Andrew Bailey said geologists have long speculated that eastern South Australia contains basement rocks equivalent to the mineral-rich Mount Read belt of western Tasmania.

“Although relatively shallow, the cover sediments of the Murray Basin are difficult to drill and have proven to be a significant deterrent to exploration,” he said.

“The Delamerian NDI campaign was designed to overcome the technical challenge of drilling beneath the Murray Basin cover and characterising the basement rocks beneath.”

The drilling campaign included both conventional drilling and innovative coiled tubing (CT) drilling techniques developed by MinEx CRC.

The Delamerian NDI campaign was the first production-scale field trial of the MinEx CRC CT drilling platform, with over 5000m drilled in 18 holes. This concerted effort has allowed researchers and drill crews to improve the CT drilling infrastructure and workflows and to benchmark performance against conventional drilling techniques.

The CT drill holes were drilled significantly faster, with less water, lower fuel consumption and subsequent carbon emissions than the conventional drill holes, delivering significant cost savings and environmental advantages.

Drill cuttings delivered by the MinEx CRC CT platform were logged and assayed by portable XRF in field providing near real-time geological feedback during the drilling campaign. Comparison between geochemistry and gamma logs indicates that the CT cuttings can be confidently attributed to a depth interval, with good sample integrity.

The Delamerian NDI campaign also saw the first deployment of MinEx CRC’s CT selective diamond coring capability, which was used to collect bottom-of-hole drill core in 16 of the 18 CT holes.

“We think the newly developed coring capability is a game-changer for the MinEx CRC CT platform,” MinEx CRC’s Chief Scientific Officer Professor David Giles said.

“Now geologists have the option to collect high-quality core samples, containing valuable textural and structural information, from any depth of their choosing”.

Before drilling, the GSSA conducted an extensive review and synthesis of prior work, collecting new geophysical data and applying cutting-edge machine learning techniques to target and prioritise drill holes. A vital component of the GSSA contribution was landholder consultation, environmental evaluations, and cultural surveys to ensure stakeholder engagement, minimise impact and manage land access at industry-leading standards.

Geological and geophysical logs and in-field geochemistry collected during the drilling campaign are now available via the South Australian Drilling Atlas . This Atlas was the first time the GSSA had released as near real-time data as possible during the drilling campaign. This allowed the GSSA, as well as companies and researchers to gain early access and visualise raw data.

Drill core and cuttings samples from the NDI drill holes will be the subject of in-depth analysis over the coming year, designed to add detail to the emerging geological model and provide guidance on the exploration techniques most likely to lead to the discovery of new deposits.



MinEx CRC is the world’s largest mineral exploration collaboration with a 10-year life and bringing together Industry, Government and Research Organisations with $220M of funding comprising of:
• $50M cash from the CRC Program
• $41M cash from geological surveys and industry
• $51M non-staff in-kind
• $78M or 311FTE staff in-kind



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