RareX Discovers 74m Copper Zone at Khaleesi’s Niobe Prospect
Key Takeaways
- Drill hole KRC012 at the Niobe Prospect returned a 74-metre zone of anomalous copper sulphide mineralisation from 77m to 151m downhole, with a peak pXRF reading of 5,724ppm Cu and a weighted average of 940ppm Cu across the full interval.
- All copper figures are preliminary pXRF field values only — not certified laboratory assays — with independent lab results expected within 4–6 weeks, making those results the key catalyst to watch.
- A second hole, KRC007, located 900 metres to the northeast, also returned elevated copper at 8m at 960ppm Cu, confirming the anomalism extends across a broad spatial footprint within the Niobe system.
- The propylitic alteration signature observed in KRC012 suggests the higher-grade core of the hydrothermal system remains untested, with future drilling designed to vector toward that source.
- Copper now sits alongside gallium, niobium, and rare earth potential at Niobe — all five priority targets within the 966km² Khaleesi Alkaline Intrusive Complex remain active exploration fronts.
Copper discovery adds new dimension to Khaleesi’s already-prospective Niobe system
RareX Limited (ASX: REE) has identified a broad zone of anomalous copper sulphide mineralisation in drill hole KRC012 at the Niobe Prospect within the Khaleesi Alkaline Intrusive Complex (KAIC) in Western Australia. Indicative pXRF readings define copper enrichment over approximately 74 metres from 77m to 151m downhole, with a peak field reading of 5,724ppm Cu (0.57%) and multiple intervals exceeding 1,500ppm Cu.
Important cautionary note: All copper figures reported here are preliminary portable XRF (pXRF) field values only. They are not equivalent to certified laboratory assays and cannot be used for mineral resource estimates. Laboratory assays are expected within 4–6 weeks.
The discovery introduces copper as an additional exploration opportunity at Niobe, sitting alongside the gallium, niobium, and rare earth potential already being evaluated by RareX at the same system.
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What the drill results show
KRC012 — the headline hole
The final drill hole on the southern line at Niobe, KRC012, intersected hydrothermally altered pyroxenite beneath a roof pendant of syenite, with sulphide alteration visible from approximately 77m downhole. Chalcopyrite was identified visually within the zone, which extends to 151m depth.
Key pXRF intervals from KRC012 (preliminary field values only):
- 74m at 940ppm Cu from 77m (weighted average composite, no grade cuts applied)
- Peak reading of 5,724ppm Cu within the zone
- Multiple intervals exceeding 1,500ppm Cu across much of the sulphide zone
- Including: 3m at 4,037ppm Cu from 127m
Drill hole KRC007, located 900m to the northeast, also returned elevated copper, with 8m at 960ppm Cu, reinforcing the spatial scale of the copper anomalism across the broader Niobe system.
Geological context
The Niobe Prospect sits within the KAIC, a district-scale alkaline intrusive complex in the East Yilgarn region of Western Australia. The Khaleesi Project covers approximately 966km² in the East Yilgarn region of Western Australia. RareX’s maiden RC program at Niobe drilled six holes totalling 805m across two lines 400m apart, a northern line and a southern line. KRC012 is the westernmost hole in the southern drilling area.
The alteration signature observed in KRC012 is consistent with propylitic alteration, which typically represents the outer halo of a hydrothermal system. RareX’s geological staff interpret this as meaning the system’s higher-grade core remains untested, with future exploration focused on vectoring towards the source of the fluids, where copper grades may increase.
| Hole ID | Easting | Northing | Total Depth (m) | Key Result (pXRF Cu) |
|---|---|---|---|---|
| KRC007 | 582,685 | 6,672,205 | 139m | 8m at 960ppm Cu (elevated; 900m NE of KRC012) |
| KRC008 | 582,783 | 6,672,205 | 144m | Background-level copper |
| KRC009 | 582,436 | 6,671,841 | 90m | Background-level copper |
| KRC010 | 582,240 | 6,671,835 | 90m | Background-level copper |
| KRC011 | 582,037 | 6,671,842 | 90m | Background-level copper |
| KRC012 | 581,837 | 6,671,839 | 252m | 74m at 940ppm Cu from 77m; peak 5,724ppm Cu |
All pXRF results are preliminary field values only. Not equivalent to certified laboratory assays.
Understanding pXRF results — what investors need to know
Portable X-ray fluorescence (pXRF) analysis is a rapid field tool that detects elemental concentrations in drill spoil directly on-site, delivering indicative readings on the same day as drilling. The instrument used at Niobe was a Bruker S1 Titan.
For exploration companies, pXRF allows geologists to quickly identify zones of interest during a drilling program so they can prioritise sampling and accelerate follow-up decisions. It is a practical screening tool, not a definitive measurement.
The critical limitation is this: pXRF results are not equivalent to certified laboratory assays and cannot be used for mineral resource estimates or economic evaluations. The style of mineralisation at Niobe has not yet been determined, and geological staff are awaiting laboratory assays and thin sections to assist modelling.
For REE shareholders, the key catalyst to watch is the laboratory assay results, expected within 4–6 weeks. Those results will confirm or refine the grades and widths indicated by the field readings.
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What comes next for RareX at Khaleesi
James Durrant, Managing Director and CEO
“The identification of a broad 74 metre zone of anomalous copper mineralisation in KRC012 is an exciting new discovery for RareX and adds another dimension to what is emerging as a highly prospective and geologically complex system at the Khaleesi Alkaline Intrusive complex.
“The pXRF results are preliminary and we are awaiting laboratory assays, however the scale and consistency of the copper anomalism across KRC012 warrants follow-up and alteration vectors suggest the hotter part of the systems is yet to be found.
“Importantly, copper now sits alongside the broader gallium, niobium and rare earth opportunity we are already evaluating at Niobe. We are integrating KRC012 into the broader program interpretation and we are excited to be part of a newly discovered mineralised system in the Albany Fraser.”
RareX has outlined the following next steps:
- Submit samples from the KRC012 mineralised interval for independent laboratory assay analysis, with results expected within 4–6 weeks.
- Complete geological interpretation of KRC012 in the context of the full Niobe RC drilling program.
- Assess all exploration methods to vector future drill programs toward the higher-grade core of the system, guided by the propylitic halo interpretation.
- Complete a full assay suite including gold to help fingerprint the style of mineralisation and assist vectoring toward higher-grade mineralisation.
Niobe is one of five priority targets within RareX’s broader KAIC program. The copper discovery does not displace the gallium, niobium, and rare earth opportunity already being evaluated at the same system. Both lines of exploration remain active as the company awaits laboratory results and completes its geological interpretation of the maiden RC program.
For investors exploring what a commercial pathway for RareX’s gallium assets could look like, our deep-dive into RareX’s Australian gallium supply chain strategy covers the Gega Elements partnership and how the company is positioning its critical minerals discoveries toward downstream processing and end-user markets.
The copper discovery at KRC012 sits within the same alkaline intrusive system already producing high-grade results, with gallium mineralisation at Niobe having returned exceptional 87g/t readings in earlier drilling that established the prospect as a multi-commodity target.
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