• CSIRO’s machine learning aided modelling has identified major extensions to rare earths basins and new prospects at OD6 Metals’ Splinter Rock project
  • Size of Centre prospect, which already has a 149Mt resource at 1,423ppm TREO, extended from 136-154km2
  • Company to determine targets within clay basin prospects for initial reconnaissance drilling


Special Report: CSIRO-led modelling has revealed major extensions to rare earths basins within OD6 Metals’ intriguing Splinter Rock project near Esperance, WA.

This has the potential to deliver significant scale for the project, which already has an inferred resource of 344Mt at 1,208 parts per million (ppm) total rare earth oxides (TREO).

Exploration carried out by OD6 Metals (ASX:OD6) has also delivered some of Australia’s thickest, high-grade REE intercepts with Phase 3 drilling returning grades of up to 6,441ppm TREO.

Not only did 92% of the holes encounter clays with >300ppm TREO content, valuable magnet REEs – which are used to fabricate permanent rare earth magnets that are essential for electric vehicle motors and wind turbines – make up an average of ~23% of the TREO grade.

Phase 3 drilling has also confirmed REE bearing clays across a 14km strike length at the Centre prospect with widths of between 4-5km.

Centre sits within a large clay basin within an elevated tableland and already has a resource of 149Mt at 1,423ppm TREO – a substantial proportion of the overall resource at Splinter Rock.


Modelling extends existing prospects

OD6 Metals OD6
CSIRO modelled depth of surface cover. Orange and red areas are interpreted to indicate thicker clay zones, with blue and green areas the granites. Pic via OD6


The application of machine-learning technology and advanced 3D modelling by Australia’s national science agency CSIRO has provided an enhanced interpretation of OD6’s Tempest airborne electromagnetic data.

CSIRO’s new modelling compares well to existing drilling, allowing it to be trained on locally-verified data to produce predictions of:

  • Thickness of surface cover, upper clay sediment zone and lower saprolite zone;
  • Maps of granite outcrops and depths of clay basin floors;
  • Targets with the thinnest cover, i.e. low stripping ratio; and
  • Prioritised target areas based on multi-factor inputs for on-going exploration work

It has also identified new prospects and expanded existing basin areas such as the key Centre prospect, which has grown in size from 136-154km2 at >40m clay thickness with large zones of 60 to >80m thick clays.

The new untested Tighthead and Loosehead prospects cover over 135km2 at >40m expected clay thickness.

“Our on-going research relationship with CSIRO continues to provide deep insights into our extremely large clay REE basins and channels,” OD6 managing director Brett Hazelden said.

“Using state-of-the art techniques and technology, the CSIRO research scientists have built a highly accurate model of clay thickness and depth of surface cover. This work is invaluable and allows us to prioritise exploration targets with a high degree of confidence.

“With new clay-basins identified and more accurate estimates of our defined basin areas, the Splinter Rock clay REE is emergent as the pre-eminent clay REE project in Australia.

“We are particularly excited about the extensions to our existing prospects, but also the newly identified basins which significantly add to our already impressive scale.”


Future work

OD6 will now determine regional targets within the identified clay basin prospects for wide space initial reconnaissance drilling to confirm rare earth grades, clays thickness, cover thickness and other geometallurgical parameters.

It will also conduct heritage and environmental surveys along with securing a DMIRs permit of work to enable Phase 4 drilling to commence.

Metallurgical samples will be selected from favourable holes while infill drilling will occur on a “best of the best” basis.



This article was developed in collaboration with OD6 Metals, a Stockhead advertiser at the time of publishing.


This article does not constitute financial product advice. You should consider obtaining independent advice before making any financial decisions.