Altamira Gold Corp. (TSXV: ALTA) has announced a significantly updated Mineral Resource Estimate (MRE) for its Maria Bonita porphyry gold deposit within the Cajueiro Project in Brazil, reporting total open-pit Indicated Resources of 25 Mt at 0.50 g/t gold (403,877 oz) and Inferred Resources of 70 Mt at 0.41 g/t gold (908,477 oz). The update represents a 150% increase in contained Inferred ounces and a 12% rise in Indicated ounces relative to the maiden estimate published in May 2025. Mineralization remains open in multiple directions, and step-out drilling is ongoing. Investors may be watching the deposit's continued expansion closely given the scale of the resource growth.

Key Points

  • Altamira Gold Corp. (TSXV: ALTA | FSE: T6UP | OTCQB: EQTRF)
  • Updated MRE at Maria Bonita delivers 908,477 oz Inferred and 403,877 oz Indicated gold at a 0.24 g/t cut-off grade
  • Total resource tonnage increased 90% and contained gold increased 82% versus the May 2025 maiden estimate; MRE effective date is September 16, 2026
  • Investors should watch ongoing step-out drilling on the western extension and near-term exploration at the Novo Sonho target

Maria Bonita Resource Growth Versus the 2025 Maiden Estimate

The updated MRE, with an effective date of September 16, 2026, was prepared independently by VMG Consultoria e Soluções Ltda under the direction of Volodymyr Myadzel, PhD, MAIG. The estimate incorporates 3,868 metres of additional drilling across 11 drill holes completed since the maiden resource. Total resource tonnage increased 90% and contained gold grew 82% overall. The constrained open-pit shell yields a calculated waste-to-mineralized-material ratio of approximately 0.4:1, and a gold price of US$3,300 per ounce was applied in the pit optimisation, reflecting the average gold price over the three years to August 2026.

Higher-Grade Component Strengthens Maria Bonita's Development Case

Beyond the headline figures, the higher-grade portion of the deposit has expanded materially. At a 0.50 g/t gold cut-off, Indicated Resources stand at 9.30 Mt at 0.75 g/t gold (225,630 oz) and Inferred Resources at 11.11 Mt at 0.80 g/t gold (286,859 oz). The release states that at this cut-off, contained gold increased 56% overall relative to the maiden estimate, including an 88% increase in the Inferred category. The presence of a near-surface saprolite resource — comprising 1.49 Mt at 0.65 g/t Indicated and 1.42 Mt at 0.38 g/t Inferred — further supports a potentially open-pittable configuration using agitated leach gold recovery.

Cajueiro District Scale and the Western Extension Drilling Programme

Maria Bonita sits approximately 7 km from the Cajueiro Central deposit, which holds independently estimated resources of 185,000 oz Indicated and 515,000 oz Inferred. Together, the two deposits underpin a growing district-scale resource base across Altamira's 280 km² concession area in Mato Grosso, Brazil. The company disclosed that 58 km² of newly accessible western ground hosts the westward extension of the Maria Bonita system, where step-out drilling is now underway. Surface mapping has also identified a continuation of the porphyry system to the west, and trenching and initial drill testing of the Novo Sonho target are planned in the near term.