Minaurum advances underground rehabilitation and exploration at Promontorio

Vancouver, British Columbia--(Newsfile Corp. - September 22, 2026) - Minaurum Silver Inc. (TSXV: MGG) (OTCQX: MMRGF) ("Minaurum" or the "Company") is pleased to report that ongoing underground rehabilitation efforts have resulted in safe access to a large section of the main haulage level and a 55-metre-deep internal shaft leading to lower levels of its historic Promontorio mine . These advancements support modern exploration efforts with preliminary channel sampling returning high-grade silver at the Promontorio Vein Zone within the high-grade Alamos Silver Project ("Alamos") in Sonora, Mexico.

Underground channel sampling conducted across mineralized structures along the edges of historically mined stopes returned the following highlights:

0.30 m of 4,142 g/t silver equivalent ("AgEq") (Table 1) ( 3,860 g/t Ag , 0.42 g/t Au, 1.91% Cu, 1.58% Pb, 2.21% Zn ) (Sample 101307)

0.50 m of 704 g/t AgEq ( 275 g/t Ag, 1.23 g/t Au , 0.34% Cu, 0.39% Pb, 13.35% Zn ) (Sample 101277)

0.50 m of 733 g/t AgEq ( 282 g/t Ag, 2.67 g/t Au , 0.36% Cu, 0.52% Pb, 8.07% Zn ) (Sample 101276)

0.50 m of 480 g/t AgEq ( 386 g/t Ag , 0.12 g/t Au, 0.69% Cu, 0.27% Pb, 0.82% Zn) (Sample 101297)

"Minaurum's 28.6 Moz AgEq inferred resource at Promontorio represents a significant portion of the Alamos Project's 55.2 Moz AgEq initial resource estimate. With more than 600 m of the haulage level and the 55 m-deep Balvanera shaft now securely accessible, we have begun detailed underground mapping and sampling that is already returning encouraging results," stated Darrell Rader, President and CEO. "We look forward to advancing rehabilitation, mapping and sampling across the historic Promontorio, Quintera and Minas Nuevas mines."

Promontorio Mine History - Promontorio Vein Zone Resource and Potential The Promontorio mine produced an estimated 70 million ounces of silver historically with underground an