Altamira Gold Expands Maria Bonita Resource by 150 Percent

Altamira Gold Corp. has updated the mineral resource estimate for the Maria Bonita porphyry deposit in Brazil, reporting a significant expansion of its gold holdings. The company announced that the updated estimate, effective September 16, 2026, reflects substantial growth in contained ounces driven by recent drilling activities that extended the known mineralized system.

The new figures indicate that the Indicated resource now stands at 25 million tonnes grading 0.50 grams per tonne of gold, containing 403,877 ounces. The Inferred resource has grown to 70 million tonnes at 0.41 grams per tonne, holding 908,477 ounces. These updates were prepared by VMG Consultoria e Soluções Ltda based on 3,868 meters of additional drilling completed between August 2022 and August 2026.

Resource growth driven by new drilling

Since the maiden estimate published in May 2025, Altamira conducted drilling below and to the west and north-west of the original resource area. This activity resulted in a 150 percent increase in contained ounces within the Inferred category and a 12 percent increase in the Indicated category. The company noted that mineralization remains open in several directions, with ongoing step-out drilling targeting the western extension identified through surface mapping.

The updated estimate is constrained within an optimized open-pit shell, yielding a waste-to-mineralized material ratio of approximately 0.4 to 1. This efficiency metric suggests favorable operating economics for potential future mining. The deposit continues to exhibit uniform gold mineralization over wide intervals, both inside and outside the porphyry intrusive boundaries, supporting the stability of the resource model.

Higher-grade sectors show substantial expansion

A high-grade sector of the resource has also expanded considerably under the new estimate. At a cut-off grade of 0.5 grams per tonne, this sector comprises 9.30 million tonnes grading 0.75 grams per tonne for 225,630 ounces in the Indicated category. The Inferred component of this high-grade zone reaches 11.11 million tonnes at 0.80 grams per tonne, containing 286,859 ounces. These figures highlight the increasing concentration of valuable material within the deposit.

Strategic position within Cajueiro district

Maria Bonita is located approximately 7 kilometers from the Cajueiro Central project, with both sites situated on open farmland near Alta Floresta in Mato Grosso. The district benefits from grid power access and a local water supply. Altamira’s total resource base across the district now includes the expanded Maria Bonita figures alongside Cajueiro Central’s 185,000 ounces Indicated and 515,000 ounces Inferred gold, as reported by investingnews.com.