Mosaic Conducts a Helicopter-Borne Magnetic Survey and Obtains Impact Work Permits on Golden Island

Montreal, Quebec–(Newsfile Corp. – March 5, 2026) – Mosaic Minerals Corporation (CSE: MOC) (“Mosaic” or the “Company”) announces that it 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 dataset from the airborne magnetic survey. This provides a new perspective combined with the large historical datasets 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 CEO. 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 (see map) 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 World War II in 1939. During this period, Tiblemont Consolidated built a camp with multiple permanent buildings, all of which are now gone. Nearly 3,350 linear meters of trenches were dug, as well as a three-compartment vertical shaft sunk to a depth of 155 meters. A 360-meter-long adit was also driven into the hillside at lake level, subsequently connected to the shaft at the 100-meter level. Underground development extends to 1,800 meters at the 360 ​​and 485-meter levels. A 5-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 g/t at a depth of just under 60 meters (GM41028). Multiple exploration programs have been carried out in previous years. Notably, in 1982, SOQUEM completed a short program of 8 drill holes (1,150 meters), 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 National Instrument 43-101. Table 1 – Drilling Results – SOQUEM 1982 (GM38876) Drill holeFrom (m)To (m)Length (m)Grade (g/t Au)Zone82-263,581,217,71,18MainIncluding75,681,25,62,99And111,18137,1025,91,42Including111,18123,5011,72,0982-656,170,514,41,25MainIncluding56,161,35,22,0167,670,52,92,9782-840,453,513,11,49MainIncluding46,851,95,12,39 It should also be noted that drill hole 82-5, located approximately 1 km northwest of the main zone, intersected a 4.7-meter interval grading 1.31 g/t 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 Corporation included in this press release has been reviewed and approved by Gilles Laverdière, P.Geo, Vice-President Exploration of Mosaic Minerals and qualified person under National Instrument 43-101 respecting information concerning mining projects (“Regulation 43-101”). About Mosaic Minerals Corporation Mosaic Minerals Corp. is a Canadian mining exploration company listed on the Canadian Securities Exchange (CSE: MOC). The Company is developing the Golden Island (Au), Amanda (Au) and Gaboury (Ni) projects located in Abitibi and James Bay (Quebec). This release contains certain “forward-looking information” under applicable Canadian securities laws concerning the Arrangement. Forward-looking information reflects the Company’s current internal expectations or beliefs and is based on information currently available to the Company. In some cases, forward-looking information can be identified by terminology such as “may”, “will”, “should”, “expect”, “intend”, “plan”, “anticipate”, “believe”, “estimate”, “projects”, “potential”, “scheduled”, “forecast”, “budget” or the negative of those terms or other comparable terminology. Assumptions upon which such forward-looking information is based includes, among others, that the conditions to closing of the Arrangement will be satisfied and that the Arrangement will be completed on the terms set out in the definitive agreement. Many of these assumptions are based on factors and events that are not within the control of the Company, and there is no assurance they will prove to be correct or accurate. Risk factors that could cause actual results to differ materially from those predicted herein include, without limitation: that the remaining conditions to the Arrangement will not be satisfied; that the business prospects and opportunities of the Company will not proceed as anticipated; changes in the global prices for gold or certain other commodities (such as diesel, aluminum and electricity); changes in U.S. dollar and other currency exchange rates, interest rates or gold lease rates; risks arising from holding derivative instruments; the level of liquidity and capital resources; access to capital markets, financing and interest rates; mining tax regimes; ability to successfully integrate acquired assets; legislative, political or economic developments in the jurisdictions in which the Company carries on business; operating or technical difficulties in connection with mining or development activities; laws and regulations governing the protection of the environment; employee relations; availability and increasing costs associated with mining inputs and labour; the speculative nature of exploration and development; contests over title to properties, particularly title to undeveloped properties; and the risks involved in the exploration, development and mining business. Risks and unknowns inherent in all projects include the inaccuracy of estimated reserves and resources, metallurgical recoveries, capital and operating costs of such projects, and the future prices for the relevant minerals. The Canadian Securities Exchange does not accept responsibility for the adequacy or accuracy of this release. NOT FOR DISTRIBUTION IN THE UNITED STATES OR ANY US NEWS WIRE SERVICES AND DOES NOT CONSTITUTE AN OFFER OF THE TITLES DESCRIBED HEREIN. The post Mosaic Conducts a Helicopter-Borne Magnetic Survey and Obtains Impact Work Permits on Golden Island appeared first on Mosaic Minerals Corp. (CSE: MOC).