Sunstone Metals (STM) investor relations material

Resource development and exploration updates

• Current resources total 3.6 million ounces at Bramaderos, with an exploration target of 5–13 million ounces being drilled for conversion to resources and a significant upgrade expected by October or November.

• New discoveries at Copete and Porotillo add an exploration target of 1.7–3.5 million ounces, with consistent mineralization and grades from surface to depth, expected to contribute to the upcoming resource upgrade.

• Both Bramaderos and El Palmar feature mineralization at surface, low strip ratios, and potential for rapid resource expansion through ongoing drilling.

• El Palmar has a 1.2 million ounce maiden JORC Resource and a 15–45 million ounce exploration target, with drilling set to restart targeting deeper porphyry systems.

• The interconnected nature of the deposits allows for immediate ore mining with minimal pre-strip, supporting a large, unified open pit operation.

Project economics and valuation

• A recent scoping study valued the project at $1.2 billion with a 23-year mine life and an all-in sustaining cost just under $1,500/oz, supported by a low 1.4x stripping ratio.

• Metallurgical test work improved gold and copper recoveries to 93% and 80%, respectively, reducing costs to $1,340/oz and adding $300 million in project value.

• Despite these metrics, the current market cap is $60 million, less than 5% of the project NPV, and the EV/resource valuation is under $10/oz, indicating a significant disconnect.

• Record high gold prices and growing copper demand driven by electrification and supply shortfalls support project economics.

• Both projects benefit from low energy and labor costs, and access to infrastructure such as grid power and highways.

Strategy and market context

• Advancing two large, long-life, low-cost gold-copper projects with a focus on value realization and scalable development.

• Projects benefit from a natural complement between gold and copper, targeting Tier 1 assets.

• Ecuador offers a favorable mining environment with low costs, USD currency, and strong government support for responsible mining.

• Recent major M&A activity in Ecuador highlights the region's attractiveness for mining investment.

• Bramaderos scoping study (April 2026) confirms low-risk geology, high-margin open pit mining, and strong community support.