Mosaic Observes Visible Gold and Identifies New Gold Zones During Its Surface Work on Its Golden Island Project

About this update from Mosaic Minerals Corp

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: 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), tension veins (extensional fractures), and dense stockwork zones, all developed within an altered and mineralized envelope measuring several tens of meters in width. This system fits perfectly into the metallogenic model of vein and shear-hosted gold deposits hosted in competent granodiorites (such as the historical Beaufor and Lac Herbin deposits or the gold zones of the Pascalis-Tiblemont Batholith). The rheological competence of the granodiorite promotes brittle behavior during regional deformations, thereby creating ideal structural traps for the circulation and deposition of mineralizing hydrothermal fluids. Link to Photo 1 Link to Photo 2 Link to Photo 3 Link to Photo 4 Potential of the NW-SE Corridor (Mag-VLF Signature over 1 km) The NW-SE system is particularly noteworthy as it coincides directly with a high-amplitude magnetic anomaly coupled with a VLF electromagnetic conductor axis. This continuous geophysical corridor extends over several kilometers in length. This combined signature (Mag-VLF) reflects the presence of shear zones and conductive faults associated with magnetic sulfides (pyrrhotite) and iron-bearing hydrothermal alterations along the corridor. To date, only one historical drill hole (SOQUEM, GM 38876) has tested this anomaly along its axis. Drill hole 927-82-5, located approximately 1 km to the NW, intersected a zone grading 1.13 g/t Au over 5.60 m within this geophysical anomaly. This geophysical corridor remains completely open and untested. Furthermore, historical drilling carried out by SOQUEM in the NE-SW corridor, where the main gold zone is located, demonstrates the fertility and continuity of significant gold grades within the host granodiorite: Table 1 - Representative historical intersections of SOQUEM (1982 - GM 38876) The presence of visible gold was noted in each of these drill holes completed by SOQUEM. Technical Work and Drilling Preparation As part of this campaign, a high-precision GPS geodetic positioning survey was carried out to accurately georeference all historical trenches, the original exploration shaft, the adit entrance, as well as the collars of the 1982 SOQUEM drill holes. Intensive and systematic geological prospecting was also conducted in the immediate vicinity of the main sector, leading to the collection of more than 340 sawn channel samples from the stripped outcrops. Laboratory analysis results will be released upon their receipt and compilation. Management Statement and Next Steps "This recent surface campaign has proven to be a resounding success, and I would like to warmly congratulate our technical team for the quality of the work accomplished," stated Mr. Jonathan Hamel, President and Chief Executive Officer of Mosaic. "The discovery of visible gold and the confirmation of multi-meter gold-bearing structures in a favorable environment greatly reinforce our confidence in the gold potential of the Île d'Or property. The integration of geophysical data (Mag-VLF) with our new field observations will allow us to target priority zones with greater precision ahead of our upcoming diamond drilling campaign scheduled for the fall of 2026." Qualified Person The scientific and technical information of Mosaic Minerals Corporation included in this press release has been reviewed and approved by Robert Gagnon, P.Geo, Director 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). Source: Jonathan Hamel President and CEO [email protected] 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. To view the source version of this press release, please visit https://www.newsfilecorp.com/release/311372

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