Mr. Jonathan Hamel reports

MOSAIC CONDUCTS A HELICOPTER-BORNE MAGNETIC SURVEY AND OBTAINS IMPACT WORK PERMITS ON GOLDEN ISLAND

Mosaic Minerals Corp. has completed an airborne magnetic survey of the entire Golden Island property. The company also announces that it has obtained authorization for impact work from the Quebec Ministry of Natural Resources. Drilling permits are expected to follow in the coming weeks in time for the drilling campaign planned for spring 2026.

"We are pleased to have a new high-resolution data set from the airborne magnetic survey. This provides a new perspective, combined with the large historical data sets, and it will help us plan the next campaign. We look forward to beginning drilling as soon as possible after the snow melts," said Jonathan Hamel, Mosaic Minerals president and chief executive officer.

The Golden Island project is accessible year-round via Regional Road 113, which connects the towns of Val d'Or and Senneterre. The property is located on Tiblemont Island and is accessible by boat from the Tiblemont Lake boat launch just before the town of Senneterre. The site contains the remains of the former Tiblemont Island gold mine. This mine was discovered in the early 1930s but never reached commercial production.

Historical work and resources

Extensive work was undertaken following the discovery of the property, then known as mining concession 282, in 1932 by Dr. Theodore Koulomzine, a renowned geologist/geophysicist, until its abrupt abandonment at the outbreak of Second World War in 1939. During this period, Tiblemont Consolidated built a camp with multiple permanent buildings, all of which are now gone. Nearly 3,350 linear metres of trenches were dug, as well as a three-compartment vertical shaft sunk to a depth of 155 metres. A 360-metre-long adit was also driven into the hillside at lake level, subsequently connected to the shaft at the 100-metre level. Underground development extends to 1,800 metres at the 360- and 485-metre levels. A five-ton mill was also in operation. Documents from that time indicate several gold-bearing zones located near the surface that could be mined using open-pit methods. A resource estimate, not compliant with Regulation 43-101, indicates 391,000 tons at a grade of approximately 2.8 grams per tonne (g/t) at a depth of just under 60 metres (GM41028). Multiple exploration programs have been carried out in previous years. Notably, in 1982, SOQUEM completed a short program of eight drill holes (1,150 metres), three of which were drilled in the main zone (see table 1).

The resource estimates described in this document are considered historical resources and do not comply with the requirements of National Instrument 43-101, Standards of Disclosure for Mineral Projects. The company does not consider the historical estimate to be a current mineral resource and does not assert that any or all of the mineralization described will be subsequently converted into mineral resources or mineral reserves defined in accordance with NI 43-101.

It should also be noted that drill hole 82-5, located approximately one kilometre northwest of the main zone, intersected a 4.7-metre interval grading 1.31 g/t gold (Au). This drill hole is associated with the same magnetic anomaly as the one linked to the main shaft.

Qualified person

The scientific and technical information of Mosaic Minerals included in this news release has been reviewed and approved by Gilles Laverdiere, PGeo, vice-president of exploration of Mosaic Minerals and qualified person under NI 43-101 respecting information concerning mining projects.

About Mosaic Minerals Corp.

Mosaic Minerals is a Canadian mining exploration company listed on the Canadian Securities Exchange (symbol MOC). The company is developing the Golden Island (Au), Amanda (Au) and Gaboury (nickel (Ni)) projects located in Abitibi and James Bay (Quebec).

We seek Safe Harbor.