Following the success of the Delamerian National Drilling Initiative (NDI), the Geological Survey of South Australia once again partnered with MinEx CRC to drill underexplored areas of the State.
In 2024 the GSSA focused on the northern Gawler Craton. Through drilling, five new basement core intersections, two basin-sediment cored intervals, and valuable cuttings have been obtained. These findings will help deepen our understanding of the geological and environmental history of the Northern Gawler, stimulating new exploration in this part of the State.
The project has now finished and the samples will become part of the South Australia Drill Core Library’s legacy collection of core and cutting samples. Once validated, field data, HyLogger and other analytical datasets will be made available to stakeholders for future use through SARIG.
Drilling contractor DIG CT Pty Ltd completed the program on budget and demonstrated the effectiveness of the innovative RoXplorer® CT Drilling System for working in remote and challenging terrains.
Check out the preliminary field data on the NDI dashboard below. For the best experience, including access to all interactive functions, we recommend clicking 'View interactive content' and viewing the dashboard in full-screen mode.
Project diary
September 2025
Almost a year on since planning the coiled tubing drilling program, the GSSA team continues to build on the momentum of the completed coiled-tubing drilling campaign. With all drill sites now rehabilitated and the NDI Dashboard live, our focus has shifted to detailed sample analysis and integration of new datasets to refine our understanding of the region’s complex geological history.
Biostratigraphy
In August, the team undertook targeted biostratigraphic sampling from the Eromanga and Arckaringa Basin intervals intersected in several NDING drillholes. Working closely with Liliana Stoian, we selected 28 key intervals for palynological analysis, with a particular focus on confirming the presence and stratigraphic position of the Bulldog Shale, Mount Toondina Formation and other key units within the Arckaringa Basin. These analyses will help refine lithostratigraphic interpretations and provide age control for the sedimentary sequences, supporting broader basin correlation efforts across the region.
Isotope Sampling
In parallel, MinEx researchers continue to dig for clues about the geological history of the region. Sampling for stable isotope analysis (C and N) from selected organic-rich intervals in the NDI drillholes will contribute to paleoenvironmental reconstructions and help assess the diagenetic history of the basin fill. The work complements ongoing SHRIMP U-Pb and Sm-Nd isotope studies on basement samples, which are expected to yield insights into crustal evolution and mineralisation potential.
Geochronology
SHRIMP U-Pb dating is being conducted on high-grade gneisses from the Coober Pedy Ridge and Mt Woods Inlier. The new dates will help constrain the timing of magmatic and metamorphic events across the Nawa Domain and adjacent terranes. Additional LA-ICP-MS and Sm-Nd isotope work is underway, with Hf-in-zircon analysis scheduled for November at Curtin University.
Integration with 1st Edition SA Geology
The new biostratigraphic and isotopic datasets will be integrated into 1st Edition SA Geology to refine solid geology interpretations of the Nawa Domain and surrounding crustal blocks. These efforts are already revealing important contrasts in metamorphic and magmatic histories across the region, with implications for mineral system models.
Looking ahead
As we move into the final quarter of 2025, the GSSA will continue validating and uploading datasets to SARIG, including HyLogger, pXRF, and downhole gamma data. A final data package and technical summary will be released in early 2026, with a dedicated industry workshop planned in late 2025to present key findings and discuss implications for exploration across the northern Gawler.
Dr Liliana Stoian selecting suitable palynology samples.
Dr Liliana Stoian preparing samples for palynology.
Legacy drilling data aids the current investigation, including biostratigraphy slides from the GOMA program.
GSSA geochronologist Dr Liz Jagodzinski analysing zircon grains from the NDI drilling program at Geoscience Australia’s laboratories in Canberra.
Dr Darwinij Subarkah choosing samples for isotope analysis.
The GSSA has just launched the NDI Dashboard, packed with preliminary data obtained from drilling samples obtained during the MinEx CRC drilling campaign in the northern Gawler Craton. The dashboard presents freshly obtained data for preliminary interpretation in a visual format which can be easily accessed and interrogated using simple dropdown menus. Users will find a metadata download link, which will direct them to our new SARIG catalogue to download presented data.
Now that the coiled tubing drilling program is complete and drill sites rehabilitated north of Coober Pedy, focus has moved onto delivering validated field data (geological observations, stratigraphic interpretation, downhole geochemistry, downhole geophysics) as well as integrate new HyLogger data into understanding the geological history of the drilling area. Hyperspectral logging will assist with final stratigraphic boundaries and confirm interpretations of the downhole pXRF geochemistry.
Collection of downhole pXRF geochemistry from legacy drillholes in the northern Gawler region is also being completed as part of the project. Combined with HyLogger data and downhole gamma, this will provide a regional comparison of the mineralogical and geochemical characteristics of the Eromanga and Arckaringa basins. This will feed into project work in the broader Northern Gawler area and help characterise the cover and deeper sedimentary basins.
GSSA will integrate the new datasets collected as part of the Northern Gawler NDI to characterise basement rocks and unravel the geological history of the northern Gawler in parallel with the SA Discovery Mapping project work in the northern Gawler Craton.
Northern Gawler National Drilling Initiative Information page on the dashboard, including a brief project description, along with drillhole information, locations and images for each drillhole.
Northern Gawler NDI dashboard displaying downhole stratigraphy, lithology and pXRF geochemistry for K, Al and K/Al in NDING_06.
With four basement intercepting drillholes completed already, the project is getting close to achieving its main goal of providing basement samples in the underexplored and under-drilled area of the northern Gawler Craton.
The drillholes have provided exciting insights into the geological history of the Eromanga and Arckaringa basin sediments. With very little basement intercepts in historic drilling, running the agile CT500 has allowed the GSSA to collect new samples to observe and analyse the composition and texture of the basement terrane, which will also be used to provide critical context to the South Australian Discovery Mapping (SADM) project, which has geological mapping that overlaps the same project area.
After a well-deserved break over the December/January holiday period, Omni GeoX and DIG CT were back on site mid-January to kickstart the remaining drilling.
At the end of January, the GSSA and MinEx CRC hosted representatives from project sponsors and affiliated companies at the Northern Gawler National Drilling Initiative (NDI) site north of Coober Pedy. This included a brief rig visit to discuss drilling parameters, as well as the new coiled tubing technology for use in resource exploration.
The GSSA team is collecting downhole portable XRF data as the chips and core are brought into South Australia’s Drill Core Library, to complement the downhole gamma and handheld magnetic susceptibility being collected on site.
Zara Woolston collecting downhole portable XRF geochemistry from the top of a completed drillhole.
Q4 2024 has seen the GSSA and collaboration partners, MinEx CRC, and commercial drilling company DIG CT successfully drill three targets in the Northern Gawler project area. Each drillhole has confirmed the assumed geology and created new questions for the GSSA and MinEx CRC researchers. The logging of the chip trays and core have created opportunities to integrate knowledge and experience from both the regional geoscience and mineral systems teams, and the energy resource and basin prospectivity teams within GSSA. Bringing together expertise across sedimentary environments and many years of expertise in the Cooper-Eromanga basin lithologies, the chance to interrogate the downhole gamma with chip and vial samples was very productive and generated a lot of discussion, which has led to new scientific questions. The cross-commodity information sharing will definitely expand the workflow to ensure high quality data and interpretation of the geological history of the project area.
In Q2 and Q3 2024 the GSSA has been carefully planning target areas for testing based on paucity of geological information in a prospective region for mineral, energy and groundwater resources. The NDI drilling near Coober Pedy commenced in early October with project collaborative partner MinEx CRC. DigCT owns and operates the coiled tubing rig and OmniGeoX is providing field support for the program. Utilising the DigCT coiled tubing rig, this program aims to collect cuttings and finish with drill core at the bottom of hole to ensure fresh samples for researchers.
With the completion of the first drillhole of the Northern Gawler project, geologists now have fresh samples into the younger Cretaceous cover and older Permian to Mesoproterozoic rocks in the Coober Pedy region of northern South Australia.
This month we hosted back-to-back workshops for the Mineral Exploration Cooperative Research Centre (MinEx CRC) at the South Australia Drill Core Library. Both workshops formed part of the planning for the National Drilling Initiative (NDI) program. The NDI sits under MinEx CRC's Program 3, which focuses on creating new tested workflows for drilling and sampling through cover, and developing scientific methods to uncover hidden mineral potential within Australia, especially taking advantage of new low-cost Coiled Tubing (CT) drilling technology and associated sensing.
The first two-day workshop included setting priorities and goals for the final three years of MinEx CRC. Discussions revolved around new products and workflows already developed and how these can be implemented. Geological Survey organisations, university researchers and partner organisations (including Geoscience Australia and CSIRO), attended the hybrid workshop.
The second workshop was aimed more locally and involved planning for GSSA’s Northern Gawler NDI program in late 2024. This workshop brought together GSSA, MinEx CRC researchers and invited resource company representatives to review current research and discuss potential geoscientific investigations for the Northern Gawler NDI project. In-depth talks were offset by practical core viewing, making the most of the Core Library’s fantastic legacy drillholes and available core layout, and sampling for research purposes.
