Estrella upgrades 274Mt of Werumata limestone to Indicated

Estrella Resources Limited (ASX:ESR) has replaced a large but entirely Inferred limestone inventory with something more useful for mine planning: 274 million tonnes of Indicated resources at the Werumata project in Timor-Leste. The upgrade covers roughly 51% of the revised 533Mt central estimate and includes about 70% of the higher-quality Product 1 material.

Bulk Density Work Drives the Classification Upgrade

The technical obstacle was not the geology but the tonnage factor. The maiden estimate relied on laboratory density measurements covering less than 3% of diamond core, leaving the entire resource in the Inferred category. Estrella subsequently expanded measurements across existing core, with the data independently reviewed and integrated by ASEAMCO, allowing parts of the BCUH and BPUH horizons to move into Indicated status.

The revised estimate comprises 274Mt Indicated and 259Mt Inferred, with 391Mt classified as Product 1 limestone averaging 83.9% acid neutralisation capacity. Product 2 contributes 33Mt, while Product 3 contributes 109Mt of higher-silica material. All figures are dry-basis Mineral Resources and include a 97% recovery factor for voids. No Measured Resource or Ore Reserve has been reported.

533Mt Resource Replaces the 621Mt Maiden Estimate

The headline number has gone backwards. Werumata’s central estimate has fallen from 621Mt to 533Mt since the maiden estimate, a point that matters even though Estrella says the modelled mineralised volume is unchanged. The company attributes the reduction solely to revised bulk densities: Product 1 falls from 493Mt to 391Mt, while Product 3 rises from 95Mt to 109Mt.

The classification milestone advances a project that was previously described as a 621Mt Inferred resource in the maiden Werumata resource. It also delivers on the density work that had been flagged as capable of upgrading confidence in parts of the deposit. That is a technical improvement, but it does not by itself establish economic reserves, production timing or commercial viability.

Development Studies and Customer Testing Move Forward

Estrella says it will use the updated estimate in technical and economic studies, while continuing discussions with potential customers about specifications, offtake arrangements and commercial applications. The proposed products would be direct-shipping ores requiring crushing and screening, with open-cut mining identified as the only economically feasible extraction method in the technical report.

The next practical tests sit outside the resource table: whether customers accept the proposed product specifications, whether port access and export logistics can be secured in Timor-Leste, and whether further drilling improves confidence beyond the currently defined areas. The company also plans additional community engagement and is assessing extensions to the limestone horizons.