Critical minerals focused explorer in Malawi, Chilwa Minerals provided an update on Phase I reconnaissance sonic drilling at its Mpyupyu West heavy mineral sands (HMS) discovery, first reported on 3 June 2026 and expanded to a target area of over 17 km² on 23 June 2026.
Sixty holes for 551 metres have now been completed, representing 22% of the planned 268-hole Phase I programme. Drilling has intersected a mineralised, free-dig saprolite unit from surface, within a stratigraphic sequence that is consistent across drill holes and sections completed thus far. Mpyupyu West adjoins the Mpyupyu Mineral Resource of 109.6Mt, which more than doubled on 19 June 20261 and positions Mpyupyu as the Company’s largest HMS deposit and its first potential development front. Both sonic rigs are now operating at Mpyupyu West.
Resource-definition drilling at Bimbi Main has been paused to focus resources on the emerging Mpyupyu West prospect.
Highlights
- Mineralised from surface – reconnaissance sonic drilling at Mpyupyu West continues to intersect a mineralised, free-dig saprolite unit overlain by a mineralised sand cover. The prospect is interpreted to be relatively uniform, with most holes intersecting moderate to strong mineralisation in on-site panning, supported by pXRF analysis. The mineralised horizon averages 7.3 metres thick and extends to a maximum of 12 metres.
- Phase I drilling 22% complete – 60 holes for 551 metres have now been completed of a planned 268- hole Phase I programme on a nominal 400 mN x 200 mE grid, including 38 holes for 361 metres in the week to 26 July 2026.
- Both rigs now at Mpyupyu West – Sonic Rig 1 and Sonic Rig 2 are both drilling the prospect, with Phase I expected to be completed in late September 2026.
- Consistent stratigraphy across the prospect – holes intersect a consistent sequence of sand, silty sand, sandy clay and free-dig, highly weathered saprolite, terminating at underlying saprock.
- Deposit style refined – drilling through the full profile now supports an in-situ, residually concentrated saprolite-hosted deposit style, rather than the Quaternary shallow lacustrine/strandline and aeolian setting of the other deposits on the licence tenement.
- Resource drilling paused at Bimbi – resource-definition drilling at Bimbi Main is 62% complete, with 166 holes for 1,843 metres drilled to date. The sonic rig active at that site has been moved to the new HMS target at Mpyupyu West.
- No drilling Exploration Results are reported in this announcement – total heavy mineral content will be determined by laboratory sink-float assay, with assay batch preparation and sample export permitting underway. First assays from Mpyupyu West are expected in October 2026.
- Hand panning extends the target – a further 153 hand-panned surface sample points have been completed at Mpyupyu West since the Company’s last update on hand panning, taking the total to 227 points. Visual heavy-mineral estimates for the new points are tabulated in Appendix 1, Table 2 and are used to guide drill planning.
Chilwa Minerals’ Managing Director, Cadell Buss, commented:
“Sixty holes into Phase I and the picture at Mpyupyu West is remarkably consistent. We are intersecting soft, free-dig saprolite from surface, hole after hole, across a target area of more than 17 square kilometres immediately west of our Mpyupyu Dune and Flat deposits, with the mineralised horizon averaging 7.3 metres thick and reaching 12 metres in places — the same system that underpins the 109.6 Mt Mpyupyu Mineral Resource. Consistency of that kind at this early stage of a reconnaissance programme is exactly what we were hoping to see, and it is why both rigs are now on the prospect.
“What has also become clearer is the nature of the deposit itself. Drilling through the full profile indicates an in-situ, deeply weathered saprolite blanket rather than the depositional sands and silty-sands at our other established resources. A residual blanket of this style sits at surface, is soft enough to free-dig, and can be laterally extensive — characteristics well suited to low-cost mining.
“With both rigs at Mpyupyu West and Phase I on track for completion in late September, we expect to be well placed to define where a resource-definition campaign should be focused, alongside the Scoping Study work already underway across our existing deposits.”
