Mosaic Announces Updated Channel Sampling Results at Golden Island, Including an Average Grade of 280.26 g/t Au over 0.5 m, and Provides a Drilling Progress Update TMX Newsfile Thu, November 12, 2026 at 8:05 AM EST 9 min read MOC.CN 0.00% GC=F -2.53% 50 samples grade above 1 g/t Au and 15 above 10 g/t Au, in 35 channels
Montreal, Quebec--(Newsfile Corp. - November 12, 2026) - Mosaic Minerals Corporation (CSE: MOC) ("Mosaic" or the "Company") announces updated results from its channel sampling program on the Golden Island gold project, in Abitibi, Quebec. The program comprises 343 samples, mostly 0.5 m long, collected from 98 channels. The samples were analyzed by fire assay, with gravimetric and metallic sieve re-assays for the highest-grade samples. The Company also provides an update on its drilling campaign of at least 2,000 metres, the start of which was announced on October 29, and which is progressing at a good pace.
Average grade of 280.26 g/t Au over 0.5 m in sample C0380541 (channel 84), i.e., the average of 154.70 g/t and 619.17 g/t Au by gravimetric finish and 66.92 g/t Au by metallic sieve.
Average grade of 82.07 g/t Au over 0.5 m in sample C0381259 (channel 6): 72.79 g/t Au by gravimetric finish, 116.26 g/t Au in the duplicate and 57.16 g/t Au by metallic sieve. The sample also contains 42.5 g/t Ag and 0.42% Cu.
Average grade of 58.05 g/t Au over 0.5 m in sample C0381370 (channel 37): 54.51 and 55.30 g/t Au by gravimetric finish and 64.34 g/t Au by metallic sieve.
Channel 61: four consecutive samples over 2.0 m returned 26.21, 61.97, 63.32 and 1.17 g/t Au by metallic sieve.
50 samples above 1 g/t Au in 35 channels, including 15 above 10 g/t Au in at least one assay.
Metallic sieve assays reveal coarse gold: C0381444 increases from 6.20 to 34.83 g/t Au, C0381450 from 8.81 to 63.32 g/t and C0381466 from 1.37 to 26.13 g/t.
Drilling progress: the campaign of at least 2,000 metres continues on the island; more than 600 metres have been drilled in 2 holes to date.
"These channel results are very encouraging," said Jonathan Hamel, President and Chief Executive Officer of Mosaic. "We have gold above 1 g/t in 35 channels, and metallic sieve assays confirm the presence of coarse gold, with several samples exceeding 50 g/t Au. In the field, the pace is excellent: the drill is turning on the island and the team is advancing quickly. 2027 is shaping up to be a promising year, with a budget that will allow us to maintain a steady work program on the island."
The diamond drilling campaign of at least 2,000 metres announced on October 29 is progressing at a good pace on Golden Island. To date, more than 600 metres have been drilled in 2 holes.
Core is logged and sampled as drilling progresses. Results will be released once they have been received and validated.
Assay Results ≥ 1 g/t Au - Channel Samples
The table presents the 50 samples with at least one assay of 1 g/t Au or more. The remaining 293 samples returned less than 1 g/t Au.
Gravimetric / initial fire assay (g/t Au)
All samples are 0.5 m long, except C0381252 (1.0 m). Lengths are measured along the channel and do not necessarily represent true thickness. The initial grade is the gravimetric result; for C0381267, C0381366, C0381374, C0381377 and C0381446, which were not re-assayed with a gravimetric finish, it is the fire assay (AA finish) result. The average grade is the arithmetic mean of the assays available for each sample (initial, duplicate and metallic sieve). Grades of 10 g/t Au and above are shown in bold.
Gold mineralization is associated with quartz veins hosted in a granodiorite with blue quartz eyes, commonly sheared and hematized, with pyrite and locally chalcopyrite and malachite.
The channels were cut with a saw in stripped bedrock, perpendicular to the structures [to be confirmed], and sampled in 0.5 m sections. All analyses were performed by Laboratoire Expert Inc. in Rouyn-Noranda (Quebec), a laboratory independent of the Company [accreditation to be confirmed].
Fire assay with atomic absorption finish (FA-GEO). Initial analysis of all samples, in ppb (detection limit 5 ppb).
Fire assay with gravimetric finish (FA-GRAV). Re-assay of samples above [1,000 ppb] Au, in g/t.
Metallic sieve (FA-MET). Re-assay of high-grade samples. The entire sample (1 to 4.5 kg) is pulverized, then screened at 100 mesh. The coarse fraction (+100 mesh) is assayed in its entirety and the fine fraction (−100 mesh) in duplicate. The final grade is the weighted average of the two fractions, based on their weights. This method is the most representative in the presence of coarse gold.
Silver, copper and zinc (AAT-7). Aqua regia digestion with atomic absorption finish.
Reference materials and blanks. Mosaic inserted a control sample approximately every 20 samples: 8 certified reference materials and 9 blanks. The standards returned 4.01 to 4.25 g/t Au by gravimetric finish (average of 4.13 g/t). All blanks returned less than 5 ppb Au, indicating no contamination.
Laboratory duplicates. Fire assay (AA finish) duplicates agree within 10% for the 12 pairs above 50 ppb. Gravimetric duplicates are more variable, reflecting the presence of coarse gold.
Metallic sieve. The two assays of the fine fraction agree within 10% in the vast majority of cases. Mosaic recalculated the final grades from the weights and grades of each fraction.
The scientific and technical information contained in this press release has been reviewed and approved by Ms. Suzie Tremblay, a member in good standing of the Ordre des géologues du Québec (OGQ No. 10664), who is a "qualified person" as defined by National Instrument 43-101 - Standards of Disclosure for Mineral Projects. All geoscientific activities related to the Golden Island project are conducted under the supervision of Ms. Suzie Tremblay, Vice-President of Explo-Logik and consultant to Mosaic Minerals Corp.
About Mosaic Minerals Corporation
Mosaic is a Canadian mineral exploration company listed on the CSE (MOC). It is advancing the Golden Island (Au), Amanda (Au) and Gaboury (Ni) projects in Abitibi and James Bay, Quebec.
For more information: Jonathan Hamel, President and Chief Executive Officer - jhamel@mosaicminerals.ca
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.
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