Mosaic Begins a Drilling Campaign of at Least 2,000 Metres at Golden Island and Returns up to 72.8 g/t Au, 42.5 g/t Ag and 0.42% Cu at Surface

Mosaic reports high-grade gold assays and begins 2,000-metre drilling at Golden Island.

What the company is saying

Mosaic Minerals Corporation is highlighting the discovery of high-grade gold at its Golden Island project in Quebec, emphasizing assay results from 343 samples with standout grades of 72.79 g/t Au and 66.92 g/t Au. The company stresses the confirmation of coarse gold through metallic screen re-assays, with fractions reaching up to 2,842 g/t Au. Management, led by President and CEO Jonathan Hamel, frames these results as validating the project's potential and justifying immediate follow-up drilling. The announcement states that a diamond drilling campaign of at least 2,000 metres is now underway, targeting the down-dip extension of high-grade surface zones. Mosaic details its QA/QC protocols, including insertion of standards and blanks at a rate of one per 20 samples, and reports no contamination. The tone is confident and data-driven, with technical details prioritized over promotional language.

What the data suggests

The assay results show that out of 343 samples, 9 returned above 10 g/t Au, 17 above 5 g/t Au, and 45 samples (13%) exceeded 1 g/t Au, indicating a significant presence of high-grade gold at surface. The highest gold grades were 72.79 g/t Au (sample C0381259) and 66.92 g/t Au (sample C0380541), with metallic screen re-assays confirming coarse gold up to 2,842 g/t Au. Sample C0381259 also returned 42.5 g/t Ag and 0.42% Cu (4,220 ppm), showing polymetallic potential. Silver and copper results include 10.0 g/t Ag (C0381265), 8.9 g/t Ag (C0381252), and up to 1,740 ppm Cu (C0381318). The drilling campaign, now active, will test the depth continuity of these high-grade zones over at least 2,000 metres in about a dozen holes, targeting depths of 150 to 300 metres. QA/QC measures were robust, with no contamination detected. The data is comprehensive for an exploration-stage update, but no resource estimate or economic assessment is provided.

Analysis

The announcement is a factual and detailed exploration-stage update, reporting specific assay results from 343 samples and confirming the commencement of a diamond drilling campaign. The majority of claims are realised and supported by numerical data, including high-grade gold, silver, and copper assays, as well as QA/QC protocols. Only a small portion of the language is forward-looking, describing the intended targets and objectives of the drilling program, which is already underway. There is no exaggerated or promotional language; the tone is proportionate to the technical results disclosed. No large capital outlay is highlighted, and the operational next steps (drilling) are already in progress, making the execution distance immediate. As an exploration-stage company, the absence of financial metrics is not a deficiency. The data supports a weak_positive signal due to the credible technical progress, but not strong_positive as no resource estimate or economic study is presented.

Risk flags

• ●There is a strong nugget effect and high assay variability, as shown by metallic screen re-assays and duplicate gravimetric results (e.g., sample C0380541 ranging from 66.92 g/t to 619.17 g/t Au), which can complicate grade estimation and resource modeling.
• ●The project is still at an early exploration stage with no resource estimate or economic study, so there is no demonstrated continuity or scale of mineralization beyond surface sampling and initial drill targeting.
• ●Operational risks include the logistical challenges of drilling on an island, as evidenced by the need to transport rigs and heavy equipment by barge, which could impact costs and timelines.
• ●No financial data, budget, or cost disclosures are provided for the drilling campaign, leaving investors without visibility into capital requirements or funding sufficiency.

Bottom line

Mosaic Minerals has delivered credible, high-grade gold assay results from surface sampling at Golden Island and has promptly mobilized a 2,000-metre diamond drilling campaign to test these zones at depth. The technical data is robust, with clear QA/QC protocols and confirmation of coarse gold, but the project remains at an early stage with no resource estimate or economic analysis. The strong nugget effect and high variability in assays highlight geological complexity and potential challenges in defining a consistent resource. Investors should expect initial drill results in the near term, but any valuation uplift will depend on whether drilling confirms continuity and scale at depth. The most important takeaway is that while the surface results are promising, the project's value hinges on the outcome of the current drilling phase.

Announcement summary

(CSE:MOC) Mosaic Minerals Corporation announced assay results for 343 samples collected during its summer 2026 exploration campaign on the Golden Island gold project in Abitibi, Quebec. The company reported gold grades of 72.79 g/t Au (sample C0381259) and 66.92 g/t Au (sample C0380541). Sample C0381259 also returned 42.5 g/t Ag and 0.42% Cu. Metallic screen re-assays confirmed the presence of coarse gold, with fractions grading up to 2,842 g/t Au. Of the 343 samples, 9 assayed above 10 g/t Au, 17 above 5 g/t Au, and 45 samples (13% of the total) exceeded 1 g/t Au. The company has commenced a diamond drilling campaign of at least 2,000 metres on Golden Island, with the drill rig and crew now on site. The drilling program will comprise a minimum of 2,000 metres in about a dozen holes, targeting the down-dip geometric extension of high-grade vein systems identified in trenches, to depths ranging from 150 to 300 metres. Best gold results include: C0381259 (72.79 g/t Au, 116.26 g/t Au duplicate, 42.5 g/t Ag, 4,220 ppm Cu), C0380541 (66.92 g/t Au, 154.70 g/t Au, 619.17 g/t Au gravimetric duplicates, 2.8 g/t Ag, 12 ppm Cu), C0381370 (54.51 g/t Au, 55.30 g/t Au duplicate, 0.8 g/t Ag, 16 ppm Cu), C0381442 (38.81 g/t Au, 44.95 g/t Au duplicate, 1.8 g/t Ag, 17 ppm Cu), and C0381449 (33.36 g/t Au, 32.43 g/t Au duplicate, 3.5 g/t Ag, 15 ppm Cu). Best silver results (≥ 2 g/t Ag) include: C0381259 (42.5 g/t Ag, 72.79 g/t Au, 4,220 ppm Cu), C0381265 (10.0 g/t Ag, 1.68 g/t Au, 212 ppm Cu), and C0381252 (8.9 g/t Ag, 7.75 g/t Au, 147 ppm Cu). Best copper results (≥ 150 ppm Cu) include: C0381259 (0.42% Cu, 4,220 ppm, 72.79 g/t Au, 42.5 g/t Ag), C0381318 (0.17% Cu, 1,740 ppm, 0.04 g/t Au, 0.9 g/t Ag), and C0381324 (0.05% Cu, 532 ppm, 0.08 g/t Au, 1.8 g/t Ag). The 343 samples were collected from a mechanical stripping and historical trench cleaning campaign, with samples mainly consisting of continuous channels averaging 0.5 metre in length. The mineralization is hosted in a blue quartz-eye granodiorite, with a complex network of shear veins, sub-vertical tension veins, and stockwork zones, often with pyrite, hematization, and visible gold. Samples were analyzed at Laboratoire Expert Inc. in Rouyn-Noranda using fire assay with atomic absorption finish, gravimetric finish, and metallic screen methods. Mosaic applied a quality control protocol by inserting certified reference materials and blanks at a rate of approximately one control per 20 samples, with no contamination detected. The scientific and technical content was reviewed and approved by Suzie Tremblay, Géo/P.Geo, qualified person as defined by NI 43-101, OGQ #10664. Jonathan Hamel is President and CEO of Mosaic Minerals Corporation.

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