Stellar Resources has intersected high-grade tin 150 metres north of its Severn resource, strengthening the geological case for a connection with the Montana deposit. Follow-up drilling is underway, but any resource or production uplift remains unconfirmed.
- 2.1m at 1.40% tin within a broader 3.9m interval at 0.82%
- Mineralisation lies outside the current Severn resource and is estimated at roughly 70% true width
- Follow-up drilling targets the area below ZM194 and the northern Severn-Montana trend
- Deeper assays remain pending from wedge hole ZS187W3A
- Potential extensions are being assessed for the PFS targeted for the first half of 2027
Severn drilling opens a link to Montana
Stellar Resources Limited (ASX:SRZ) has put a potentially important 150-metre gap under the microscope at its Heemskirk Tin Project in Western Tasmania, reporting high-grade tin outside the current Severn resource and along trend towards Montana.
Hole ZM194 returned 3.9 metres at 0.82% tin from 206.1 metres, including 2.1 metres at 1.40% tin. A second zone returned 3.7 metres at 0.41% tin from 214 metres, including 0.9 metres at 1.39% tin. The company says the results support the continuity of the Severn structure and the possibility that Severn and Montana could ultimately form one mineralised zone.
The result extends the development story established by the resource growth at Severn. Stellar's July resource update lifted Severn by 64%, while the broader Heemskirk inventory now stands at 13.36 million tonnes grading 0.86% tin for 115.3 kilotonnes of contained tin. That existing resource base provides the backdrop, but ZM194 is still a single hole rather than a new resource estimate.
Follow-up drilling will test continuity
Stellar has immediately started hole ZS197 below ZM194, targeting the extension towards historic hole ZS140. That earlier hole recorded 10 metres at 0.43% tin from 794 metres and 1.1 metres at 2.24% tin from 855.4 metres. A second rig is drilling north of Montana towards the historic Donnolly's mine, testing whether the Severn trend continues beyond the latest result.
The company is also waiting on assays from wedge hole ZS187W3A, drilled to 850 metres below the current Severn resource. The hole intersected the mineralised zone at a high oblique angle, with core being cut for laboratory analysis. These results matter because the deeper Severn system remains open down dip and down plunge, although the filing does not establish how much additional mineralisation may be present.
PFS will weigh a larger production profile
ZM194's reported intervals are downhole widths. Because the hole intersected the modelled orebody at about 45 degrees, Stellar estimates true widths at roughly 70% of the quoted lengths. That adjustment does not remove the significance of the grade, but it is essential when considering the potential scale of the extension.
Stellar is incorporating the possible shallow Severn extensions and Montana into trade-off studies for its prefeasibility study. The work is examining both a standalone operation and the use of nearby infrastructure, alongside mining schedules and processing configurations. Completion is now targeted for the first half of 2027, rather than treating the drilling result as an immediate change to project economics.
The company says tin prices remain above US$54,000 a tonne, which supports the strategic case it makes for Heemskirk. The more immediate test, however, is geological: whether follow-up holes can demonstrate enough thickness, grade and continuity to justify a revised resource and a larger mine plan. Until then, the Severn-Montana connection is a promising interpretation, not an established deposit.
Bottom Line?
The next assays from ZS197, ZS187W3A and drilling north of Montana will determine whether one encouraging intersection can become a meaningful addition to the Heemskirk mine plan.
Questions in the middle?
- Will follow-up drilling confirm continuous mineralisation between Severn and Montana rather than isolated high-grade zones?
- How will the pending deeper assays affect the next Mineral Resource Estimate and the PFS mine schedule?
- Can the potential expansion support a larger production profile without materially increasing mining or processing complexity?