Kairos Minerals Limited (ASX:KAI) has reported significant high-grade rare earths assays from its Roe Hills Project, situated 110km east of Kalgoorlie in the Eastern Goldfields of Western Australia, following a reconnaissance program involving 83 RC drillholes covering 11,138m in October, with a focus on high-priority lithium, rare earth element (REE), and gold prospects at the Black Cat, Crystal Palace, and Blue Jay locations.
Figure 1: Roe Hills North project area showing the location of RC drill collars drilled on a background image of regional geology.
High-Grade Assays at Black Cat Prospect
The drilling activities at the Black Cat prospect have revealed a substantial and unexpectedly widespread high-grade rare earth element (REE) mineralisation, positioning it as a potentially significant discovery according to Kairos.
Originally targeting lithium anomalies, the initial drilling unearthed thick, high-grade REE mineralisation within clays above previously unknown syenite and monzonite intrusions.
While lithium pegmatites were not encountered as anticipated, the remarkable multi-element assay results, including standout intersections such as 28m @ 3854ppm TREO with 4m @ 23,182ppm (2.31%) TREO, prompted a reassessment of the site’s potential.
Other significant rare earth results at Black Cat include:
- 48m @ 1631ppm TREO from 44m incl 12m @ 4332ppm TREO from 48m (RHRC153)
- 36m @ 1586ppm TREO from 36m incl 12m @ 3187ppm TREO from 44m (RHRH125)
- 20m @ 2100ppm TREO from 44m incl 8m @ 3152ppm TREO from 48m (RHRC126)
- 114m @ 1185ppm TREO from 40m incl 12m @ 2533ppm TREO from 40m and 16m @ 2178ppm TREO from 108m (RHRC127)
- 36m @ 1826ppm TREO from 36m incl 24m @ 2390ppm TREO from 40m (RHRC128)
The comprehensive results from all holes at Black Cat underscore the strategic importance of this finding and warrant further exploration efforts, including additional drilling to test for extensions to the mineralisation.
Figure 2: Black Cat REE drill results.
Figure 3: Cross-section A-A`with rare earth intercepts.
Black Cat’s mineralisation is rich in neodymium + praseodymium rare earths (NdPr) and magnet rare earths (Mag REO), with NdPr ratios averaging 23% of total rare earth oxides (TREO) and Mag REO ratios averaging 28% of TREO, reaching local peaks of 38% and 47%, respectively.
This high abundance is unusual compared to most REE deposits, highlighting the significance of Black Cat’s rare earths.
Impressively, over 90% of the drillholes tested for REEs returned significant intersections (>500ppm TREO), emphasising the widespread presence of these elements.
The mineralisation occurs in deeply weathered clays, forming a broad, thick, sub-horizontal sheet-like body of REE-enriched material that extends in all directions and remains open.
Additionally, the mineralisation is mainly non-visual, forming at the transition from upper saprolite to lower saprolite and through to the base of complete weathering, with constrained occurrences in the syenite and monzonite intrusions and their immediate country rock.
Additional Discoveries at Crystal Palace
Assay results for the remaining 26 RC holes at Crystal Palace also highlight successful lithium exploration.
Targeting a pegmatite swarm with strong lithium indicators, the drilling revealed steeply-dipping pegmatites with consistent lepidiolite presence.
Encouraging lithium grades were noted, including 2m @ 0.33% Li2O and 1m @ 0.14% Li2O, with the presence of lepidiolite promising from an LCT perspective.
The mapped pegmatite swarm extends under shallow cover to the west, and an ongoing gravity survey aims to identify potential drill targets in that area.
Significant lithium results at Crystal Palace include:
- 2m @ 0.33% Li2O from 98m (RHRC195)
- 1m @ 0.14% Li2O from 8m (RHRC172)
- 4m @ 0.12% Li2O from 96m (RHRC163)
Table 1: Significant drill intercepts for lithium at Crystal Palace >0.1% Li2O
Blue Jay Drilling Results
Drilling efforts at Blue Jay, aimed at testing REE soil anomalies for significant mineralisation in both regolith clays and primary granitic rocks, resulted in nine completed RC drillholes.
No substantial REE mineralisation was encountered, attributed to the absence of a well-developed clay-rich weathered profile in the granite body, unlike the observed profile at Black Cat.
Despite the overall disappointment, the broader Blue Jay area remains under shallow cover, and ongoing gravity data collection may reveal additional intrusive bodies, presenting potential for future REE mineralisation targets.
Figure 4. Crystal Palace and Blue Jay drill results. There are no significant REE results to report from Blue Jay.
Next Steps for Exploration
The upcoming steps for exploration include completing the gravity survey at Black Cat and Blue Jay areas to map subsurface intrusions and fault zones accurately.
Initial metallurgical testwork for Black Cat REE will focus on understanding the nature of the clay-hosted REEs and exploring potential beneficiation pathways.
Drill-planning for more cost-effective aircore programs is slated to commence once the distribution of syenite and monzonite intrusions for REE mineralisation is known.
Dr. Peter Turner, Kairos Minerals Managing Director, commented that the latest results provide evidence of a substantial clay-hosted rare earths discovery near Kalgoorlie.
“These latest results provide more firm evidence that we have a substantial clay-hosted rare earths discovery very close to Kalgoorlie,” he said.
“The results are clearly exceptional for clay-hosted REE mineralisation, with high grades and thick intersections recorded over such a large area, along with the high ratio of valuable magnet REEs to total REEs.”
“The gravity survey now underway is expected to identify numerous additional granitic targets to drill and we see an opportunity to complete some early metallurgical testwork to understand if we are dealing with an ionic REE discovery and whether we can increase the grades further during a simple beneficiation process.”
KAI’s Australian Stock Exchange-listed share price closed 14.29% higher and is currently trading at $0.016 (2.45pm UTC+ 8 hours).