The indicated resource for Heemskirk is now 24% larger at 3.52 million tonnes grading 1.05% for 36,991t contained metal.
That increases to 45,271t contained tin if the lower-grade St Dizier satellite deposit is added in.
Indicated resources have increased 58% since a scoping study was completed in 2019, however there has been a minor 5% reduction in the total resource to 7.48Mt at 1.04% for 77,872t following the removal of the Oonah resource that could not be completely offset by improvements in modelling at Queen Hill.
The exclusion of Oonah's 5382t was due to its distance from the three other Heemskirk deposits, a very high stannite content, and disappointing results from two holes drilled in 2021.
Stellar executive director Gary Fietz said two additional phases of infill drilling at the Severn had delivered an improved understanding of the mineralisation as the company strikes to complete a prefeasibility study later this year.
The project is at Zeehan, about 20km from the long-lived Renison tin mine.
While tin prices have fallen from above US$29,000 in recent months to around $25,806/t overnight as deteriorating economic indicators from China have weighed on base metals, Fitch Solutions has warned of a looming supply crunch in the global tin market from 2024 given Myanmar's restrictions on mining in Wa state and Indonesia's ban on exporting tin ingots.
Wa alone accounts for 10% of global tin supply.
Stellar ended the June quarter with cash of A$1.6 million.
Shares in the explorer were up 9% today at 1.2c, capitalising the company at $13 million.
It has traded at 0.9-1.7c over the past year.