Mosaic identifies visible gold and new zones at Golden Island

Montreal, Quebec--(Newsfile Corp. - August 25, 2026) - Mosaic Minerals Corporation (CSE: MOC) ("Mosaic" or the "Company") is pleased to announce the successful completion of a first phase of stripping, mapping, and channel sampling work on its Île d'Or gold property, located in Abitibi, Quebec.

Highlights:

Discovery of new gold zones in the southwestern extension of the main showing.

Recurrent presence of visible gold observed within multiple sampling channels.

Confirmation of a complex structural network composed of shear veins, extensional/tension veins, and stockwork networks hosted within a mineralized granodiorite matrix over several tens of meters in width.

Major geophysical corridor of over 1 km associating a high-amplitude magnetic anomaly and a VLF electromagnetic conductor, historically validated by a drill hole that intersected 1.13 g/t Au over 5.60 m.

More than 340 channel samples collected and shipped for analysis.

Uncovering of a Favorable Structural and Lithological Framework

The recent surface work aimed to facilitate access to the mineralized zones, characterize the geometry of the gold-bearing structures, and prepare the drill pads for the upcoming diamond drilling campaign scheduled for the fall.

The stripping carried out in the main sector helped to clarify the architecture of the known mineralized zones, while the work executed in the southwestern extension revealed new mineralized zones that had never been documented before. Several channel samples taken from these newly stripped areas highlighted the presence of visible gold in various veins (See photos links below).

Geologically and structurally, the mineralization develops along two major preferred orientations: North-West - South-East (NW-SE) and North-East - South-West (NE-SW). These structures consist of a complex network of ordinary veins (massive shear veins)