Altamira Gold Announces Significant Increase in Mineral Resources at the Maria Bonita Porphyry Gold Deposit, Cajueiro District, Brazil

Altamira Gold Corp. (ALTA) released an updated, independently prepared NI 43-101 Mineral Resource Estimate (MRE) for the Maria Bonita porphyry gold deposit, effective September 16, 2026. The estimate was completed by VMG Consultoria e Soluções Ltda under the direction of Volodymyr Myadzel, PhD, MAIG.

At a 0.24 g/t Au cut-off, the updated resource includes: - Indicated: 25 Mt @ 0.50 g/t Au for 403,877 oz. - Inferred: 70 Mt @ 0.41 g/t Au for 908,477 oz. - Total contained gold: ~1.31 moz, versus ~0.72 moz in the May 5, 2025 maiden estimate — an +82% increase (+12% Indicated, +150% Inferred). Tonnage rose 90%.

The resource is constrained within an optimised open-pit shell with a waste-to-ore ratio of ~0.4:1. A higher-grade component at a 0.5 g/t cut-off includes Indicated 9.30 Mt @ 0.75 g/t (225,630 oz) and Inferred 11.11 Mt @ 0.80 g/t (286,859 oz), representing a +56% overall increase in contained gold (+28% Indicated, +88% Inferred). Near-surface saprolite comprises 1.49 Mt @ 0.65 g/t (30,899 oz) Indicated and 1.42 Mt @ 0.38 g/t (17,172 oz) Inferred.

Pit-optimisation parameters include US$3,300/oz gold, 90% recovery, 0.35 Mt/yr production rate, 8% discount, OPEX $5.0/t, G&A $2.5/t, processing $9.0/t, 90% mining recovery, and 10% dilution. Since the maiden estimate, 3,868 m of additional drilling in 11 holes has been completed. Mineralization remains open west, south and at depth, with step-out drilling ongoing on the newly accessible western extension.

The full NI 43-101 technical report will be posted on SEDAR+ within 45 days. The release includes the caveat: "Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability." True widths have not been determined.

Altamira Gold Corp. (ALTA) reported an 82% increase in contained gold at its Maria Bonita project, raising the resource estimate from approximately 0.72 million ounces to 1.31 million ounces. This expansion, combined with the Cajueiro Central deposit’s 185,000 ounces of Indicated and 515,000 ounces of Inferred resources, brings the total district contained gold to roughly 2.0 million ounces. The update follows a drill campaign that began with the deep MBA-032 hit of 395.5 meters at 0.4 grams per tonne in October 2025, continued through step-outs at MBA-036, 037, 038, and 039 west and north between May and July 2026, and culminated in the Maria Bonita West discovery disclosed on August 25, 2026, via holes MBA-042 and 043.

The growth in contained ounces is driven primarily by an increase in the lowest-confidence category. Indicated resources rose 12%, from 357,800 to 403,877 ounces, while Inferred resources increased 150%, from 362,400 to 908,477 ounces. Consequently, the resource mix shifted from approximately 50% Indicated and 50% Inferred to roughly 31% Indicated and 69% Inferred. Inferred ounces require further infill drilling and capital to demonstrate economic viability.

Grade trends diverged between categories. The Inferred grade declined from 0.44 grams per tonne to 0.41 grams per tonne, whereas the Indicated grade rose from 0.46 grams per tonne to 0.50 grams per tonne. The addition of bulk tonnage at the margin is consistent with a larger pit shell rather than a richer deposit.

A significant portion of the expansion resulted from a change in the gold price construct rather than new discovery. The maiden estimate utilized a gold price of US$2,780 per ounce, while the current Mineral Resource Estimate (MRE) uses US$3,300 per ounce, a 19% increase. This higher assumption enlarged the optimized pit shell, incorporating peripheral, lower-grade material. Although the cut-off grade rose from 0.20 to 0.24 grams per tonne, the price uplift contributed substantially to the headline figure.

The release does not include an economic study. As a resource estimate, it contains no Preliminary Economic Assessment (PEA), Pre-Feasibility Study (PFS), net present value (NPV), capital expenditure, or mine plan. The pit optimization assumes a production rate of 0.35 million tonnes per year, implying a modest-scale conceptual operation of approximately 5,000 to 6,000 ounces per year at these grades. The elevated-grade sector, ranging from 0.75 to 0.80 grams per tonne, remains low by global standards and would be marginal at mid-cycle gold prices.

Altamira Gold Corp. remains pre-revenue with a going-concern flag, no debt, and a shrinking cash balance. The company’s release contains no economic data.

Altamira Gold Corp. (TSXV: ALTA, FSE: T6UP, OTCQB: EQTRF) is a pre-revenue junior explorer focused on gold in Brazil's Juruena/Alta Floresta Gold Belt, a region with historical placer production exceeding 6 moz. The company controls over 90,000 hectares across four projects, with the Cajueiro Project serving as the flagship. Covering 24,372 hectares, the Cajueiro Project is located approximately 75 km NW of Alta Floresta, Mato Grosso.

The district hosts two NI 43-101 resources about 7 km apart: Cajueiro Central, which contains 185,000 oz Indicated and 515,000 oz Inferred resources, and Maria Bonita, which holds approximately 1.31 moz from this update. The area also includes untested porphyry targets including Novo Sonho, Tavares Norte, Guillermo, Serafim, and Sossego.

Infrastructure is strong, featuring road access, grid power via a transmission line crossing the project, local water, and a 1.8 GW hydropower plant approximately 20 km west. The region is open farmland.

Management includes President and CEO Michael Bennett, a geologist with 35+ years of experience; Chairman Alan Carter, formerly of BHP; and CFO Soraia Morais. Dr. Richard Sillitoe, a world-renowned porphyry expert, serves as technical advisor since December 2025. Qualified persons include Fernando Benegas (FAusIMM) and Volodymyr Myadzel (VMG).