Chilwa Minerals Ltd (ASX:CHW) has expanded the known extent of niobium mineralisation at its Nakombe target in southern Malawi after drilling confirmed mineralisation at the southern end of the alkaline syenite intrusion, supporting the scale potential of the emerging critical minerals discovery.
Results from drill hole MPYDD015 returned a headline intercept of 22 metres at 0.228% Nb₂O₅ from 349.5 metres, including 10 metres at 0.238% Nb₂O₅ and 2 metres at 0.275% Nb₂O₅. The higher-grade interval sits within a broader 161.5-metre mineralised zone averaging 0.165% Nb₂O₅ from 240 metres to the end of the hole.
The results are based on portable XRF (pXRF) analysis, with laboratory ICP-MS assays pending.
Map showing Mpyupyu REE/Nb drill hole collar positions, completed and planned, as well as Phase 2 drilling positions on the northern and eastern extents of the target. Coordinate system: WGS 1984 UTM Zone 36S.
Southern extension strengthens geological model
MPYDD015 is the southernmost hole drilled at Nakombe and was designed as a "scissors hole" paired with previously drilled MPYDD009. Together, the two holes have confirmed continuity of niobium mineralisation across the approximately 270-metre strike length tested to date.
The hole intersected basement gneiss before entering the target alkaline syenite intrusion at around 190 metres depth. Niobium grades increased progressively downhole, supporting Chilwa's interpretation of a large intrusive body plunging to the south or southwest.
These latest results complete the geological picture across the currently drilled extent of the intrusion and further demonstrates the scale of the mineralised system.
Section line A-B (looks East) showing MPYDD009 (pXRF- left of drill trace), MPYDD015 (pXRF- left of drill trace). Core logging and pXRF results from MPYDD015 support the interpretation of a plug-to-pipe like intrusive body plunging to the south or southwest (right of section).
“MPYDD015 confirms niobium mineralisation at the current southern extent of the Nakombe intrusion, completing the picture across the full strike length we’ve tested to date. A 22 metre intercept at 0.228% Nb₂O₅ (pXRF) within a wider 161.5 metre zone — at the opposite end of the system from MPYDD009 — is a strong result for our southernmost hole," Chilwa Minerals’ managing director, Cadell Buss, said.
"Critically, MPYDD015 and MPYDD009 form a scissors pair — drilled from opposite ends of the intrusion on opposing azimuths — and both holes have returned meaningful Nb₂O₅ intervals. With every hole we drill, the scale of this niobium system continues to grow, and we are now working towards definition of a maiden Exploration Target — with ICP-MS confirmation of pXRF results from further holes expected to support that work in the near term.
"Combined with the significant work already completed on our Mpyupyu Heavy Mineral Sands deposit, and the work ongoing in pre-resource HMS drilling at the new Mpyupyu West HMS discovery these Niobium results position Chilwa’s interests in the Mpyupyu area alone, as a truly unique, multi-commodity critical minerals asset.
"With two rigs running and a potential third on the way, we are accelerating the programme into ideal conditions in Malawi. ICP-MS results for MPYDD007, MPYDD009 and MPYDD015 are pending, further pXRF results will follow shortly, and we look forward to results from the remaining holes in this first phase of drilling at the Nakombe target.”
Drilling campaign accelerates
Chilwa now has two diamond rigs operating at Nakombe, with a potential third rig under consideration as drilling conditions improve in southern Malawi. The company has completed around 2,866 metres of drilling across 15 holes at the target.
Current drilling is focused on testing extensions of the mineralised system. One rig is drilling hole MPYDD017 on the western margin of the intrusion, while the second rig is testing the eastern flank through hole MPYDD014.
The target remains open to the northeast, south, east and southeast, as well as at depth, providing multiple opportunities for expansion.
Building toward a maiden exploration target
The latest results continue to strengthen Chilwa's confidence in the scale and continuity of the Nakombe niobium system as it works toward defining a maiden Exploration Target.
Importantly, the company noted that previous comparisons between pXRF and laboratory ICP-MS assays suggest the portable XRF method may understate niobium grades in higher-grade zones, potentially providing upside when final laboratory results are received.
The company also sees the discovery as complementary to its existing heavy mineral sands and rare earths interests in the Mpyupyu area, creating a diversified critical minerals portfolio within a single project area.
What's next?
Three holes remain in the current Phase 1 drilling campaign, while an additional 11 holes have been added to a Phase 2 program targeting eastern and northern extensions of the Nakombe system.
Upcoming catalysts include:
- ICP-MS assay results for holes MPYDD007, MPYDD009 and MPYDD015;
- Further pXRF results from ongoing drilling;
- Petrographic analysis of key lithologies;
- QEMSCAN mineralogical studies and metallurgical testing; and
- Continued resource-definition drilling aimed at expanding the mineralised footprint.
About Chilwa Minerals
Chilwa Minerals is a Malawi-focused critical minerals explorer advancing multiple projects within its Lake Chilwa licence area. The company's portfolio includes the Nakombe niobium-rare earths discovery, a broader carbonatite-hosted rare earths exploration program, heavy mineral sands resources around Lake Chilwa and an emerging ionic clay rare earths initiative.
At Nakombe, Chilwa is undertaking pre-resource diamond drilling aimed at defining the geometry and continuity of niobium mineralisation ahead of a maiden resource estimate.