Sunstone Withdraws Bramaderos Production Forecasts Citing Inferred Resource Reliance

Sunstone Retracts Forward-Looking Statements on Bramaderos

Sunstone Metals (ASX:STM) has pulled back the production targets and forecast financial information from its recent Bramaderos Gold-Copper Project Scoping Study, acknowledging that the initial projections leaned too heavily on Inferred resources without a reasonable basis. This move follows consultation with the ASX, which advised the company that the forward-looking statements lacked a sufficient foundation due to the proportion of Inferred material underpinning the production profile.

The original scoping study had presented a production profile that relied exclusively on 100% Indicated resources in the early years, before shifting predominantly to Inferred resources for the remainder of the mine life. Sunstone now advises investors not to rely on those production targets or financial forecasts as a basis for investment decisions.

Resource Classification and Geological Continuity

The Bramaderos deposits are porphyry systems characterised by extensive, continuous low-grade mineralisation within large hydrothermal alteration zones. Sunstone highlights the consistent geometry and predictable grade distribution, which suggest a strong potential to convert a significant portion of the Inferred resources to Indicated. The ore bodies appear relatively undisturbed by structural faulting, reducing uncertainties typically associated with resource conversion.

This geological confidence underpins the company’s decision to proceed with infill drilling aimed at upgrading the resource classification. The ongoing drilling campaign at Copete and Porotillo is part of this strategy, with an updated Mineral Resource Estimate expected later in calendar 2026. These efforts build on recent successes that have demonstrated substantial mineralisation continuity and lateral extensions within the project area, supporting resource growth ambitions.

Project Viability and Next Steps

Sunstone emphasises that the project’s viability was established based on processing Indicated material alone, supported by the sizeable Mineral Resource already defined. The company plans to commence optioneering studies in 2026/27 to refine project parameters further. Meanwhile, infill drilling remains a priority to solidify the resource base and reduce reliance on Inferred material in future production profiles.

This retraction comes shortly after the company’s earlier confirmation of the material impact of the Bramaderos scoping study following an ASX inquiry into unusual share price movements prior to the study’s release. The drilling program underpinning resource growth, including the strong results from Copete and Porotillo, remains on track to bolster the project’s fundamentals.

Investors will be watching how the updated resource estimate and subsequent studies reshape the project's outlook, especially given the uncertainties introduced by the initial overreliance on Inferred resources.