Sunstone Metals Intersects Wide Gold-Copper Zones at Porotillo, Boosting Resource Potential

Sunstone Metals (ASX: STM) has released significant gold-copper drill results from its Porotillo prospect within the Bramaderos project, intersecting 200m and 151m from surface.

These results extend known mineralisation and bolster the company's strategy to upgrade the Copete-Porotillo exploration target into JORC Mineral Resources in the second half of 2026.

Hole PTDD006 returned 200m at 0.62 g/t Au-Eq (0.38 g/t Au, 0.14% Cu) from surface, including a higher-grade interval of 19m at 1.01 g/t Au-Eq (0.77 g/t Au, 0.15% Cu) from surface.

Hole PTDD007 also intersected 151m at 0.54 g/t Au-Eq (0.34 g/t Au, 0.12% Cu) from surface, including 26m at 0.84 g/t Au-Eq (0.53 g/t Au, 0.19% Cu) from surface.

These latest intercepts extend gold and copper mineralisation an additional 380m to the southeast of prior hole PTDD004 to now cover a total length of 480m.

Supporting Resource Upgrade Strategy

The ongoing drill program is integral to Sunstone Metals' broader strategy.

The results specifically support the company's plan to convert the conceptual Copete-Porotillo exploration target into Mineral Resources during the second half of 2026.

An expanded Porotillo trenching program is also underway aiming to improve surface definition and cost-effectively supplement drill data, aiding the anticipated resource update.

Significantly, all 12 assayed holes in the current drilling program have returned long gold-copper mineralised intersections.

These discoveries lie outside the existing 3.6Moz Bramaderos Mineral Resource, indicating strong potential for growth.

Prior Scoping Study Issues

Sunstone Metals previously made headlines when it retracted its Bramaderos Scoping Study following an ASX advisory that the company lacked a reasonable basis for its production targets and financial forecasts, primarily due to a reliance on Inferred Resources.

In response, the company is now focusing intensely on converting Inferred resources to Indicated resources through targeted infill drilling.

This work is crucial for future optioneering studies and to establish a more robust resource base.

An updated Bramaderos Mineral Resource estimate is anticipated later in 2026, which will be a key milestone for Sunstone Metals.

Exploration Target Details

The Copete-Porotillo exploration target is estimated to contain between 135-180Mt at a grade of 0.40-0.60 g/t AuEq2, equating to 1.7-3.5Moz AuEq1.

The company has previously cautioned that Exploration Targets are conceptual in nature and that the conversion of these targets to Mineral Resources remains uncertain.

Previous drilling efforts at the Melonal prospect, another part of the Bramaderos project, also yielded wide mineralisation.

For instance, hole MEDD003 intersected 250m at 0.43 g/t AuEq from surface.

Sunstone's Resource Ambitions

Sunstone Metals continues to demonstrate broad gold-copper mineralisation at Bramaderos, with recent results from Porotillo supporting its resource expansion strategy.

While progress is being made towards a 2H 2026 resource update, the shadow of the retracted scoping study means investors will be looking for concrete evidence of resource conversion and credible economics in future studies.