Minaurum Advances Underground at Promontorio Mine

Columbia, (Newsfile Corp. - September 22, 2026) - Minaurum Silver Inc., a Vancouver-based silver exploration company, has made significant progress in the rehabilitation and exploration of its historic Promontorio mine in Sonora, Mexico. The company has secured safe access to a substantial section of the main haulage level and a 55-metre-deep internal shaft, which now leads to lower levels of the mine. These advancements are crucial for modern exploration efforts, as preliminary channel sampling has revealed high-grade silver within the Promontorio Vein Zone of the Alamos Silver Project.

The channel sampling conducted across mineralized structures along the edges of historically mined stopes has returned several highlights. The first sample, Sample 101307, yielded 0.30 meters of 4,142 g/t silver equivalent (AgEq), which includes 3,860 g/t silver, 0.42 g/t gold (Au), 1.91% copper (Cu), 1.58% lead (Pb), and 2.21% zinc (Zn). The second sample, Sample 101277, produced 0.50 meters of 704 g/t AgEq, with 275 g/t silver, 1.23 g/t Au, 0.34% Cu, 0.39% Pb, and 13.35% Zn. The third sample, Sample 101276, returned 0.50 meters of 733 g/t AgEq, containing 282 g/t silver, 2.67 g/t Au, 0.36% Cu, 0.52% Pb, and 8.07% Zn. Lastly, Sample 101297 provided 0.50 meters of 480 g/t AgEq, with 386 g/t silver, 0.12 g/t Au, 0.69% Cu, 0.27% Pb, and 0.82% Zn.

Minaurum Silver Inc. has a 28.6 Moz AgEq inferred resource at the Promontorio mine, which represents a significant portion of the Alamos Project's 55.2 Moz AgEq initial resource estimate. With more than 600 meters of the haulage level and the 55-meter-deep Balvanera shaft now securely accessible, the company has initiated detailed underground mapping and sampling, which has already yielded encouraging results.

The Promontorio mine, which historically produced an estimated 70 million ounces of silver, has underground and surface mine workings extending over a distance of more than one kilometer. Historical sampling and mapping of mine dumps at Promontorio have revealed a 1-meter-wide boulder of massive sulfide vein assaying 3,320 g/t silver, 54.7 g/t gold, 25% copper, 6.5% lead, and 1.1% zinc, indicating the high grades exploited by early miners. The Promontorio vein zone accounts for 28.6 Moz AgEq of Minaurum's total inaugural inferred resource estimate of 55.2 Moz AgEq (34.8 Moz Ag, 35.6 Koz Au, 50.99 Mlbs Cu, 114.77 Mlbs Pb, and 237.80 Mlbs Zn) from the Europa, Promontorio, and Travesia vein zones.

The rehabilitation work undertaken by Minaurum Silver Inc. has secured access and installed lighting to the first 600 meters of the Promontorio mine's haulage level and installed pumps in the Tirito and Balvanera shafts. In the 55-meter-deep Balvanera shaft, crews installed a marine ladder to 45 meters, providing access to three lower levels at 12, 20, and 45 meters. The accessible parts of the Promontorio mine have been surveyed using a LIDAR scanning survey system, which has provided detailed images of the underground workings, serving as the base for geological mapping and sampling. The LIDAR surveys are integrated into the project's topographical model, which includes all drill-collar and down-hole surveys, further refining the geological model at Alamos.

Minaurum Silver Inc. is currently planning further underground rehabilitation work at workings at the Quintera mine in the central area and the Minas Nuevas, Cotera, and Pulpito Vein Zones in the northern part of the Alamos project area. The company, managed by a strong technical and finance team, continues to build on its founders' legacy of creating shareholder value by acquiring and developing a pipeline of Tier-One precious and base metal projects.