Alamos Gold Inc. reported new results from its underground exploration program at the Young-Davidson mine. Underground exploration drilling from both the mid and lower mine extended higher-grade gold mineralization within multiple zones in the hanging wall of the Young-Davidson deposit. In addition, expansion drilling within the Young-Davidson syenite continues to extend gold mineralization beyond Mineral Reserves and Mineral Resources.
South Syenite Zone: high-grade gold mineralization intersected within a syenite intrusion located in the hanging wall, 285 metres (?m?) south of the Northgate Shaft in an area that has seen limited historical drilling. Mid-Mine Hanging Wall Zones: high grade gold mineralization extended within new hanging wall zone discovered in 2024. The zone contains a new style of mineralization and is located in proximity to existing infrastructure, to the south of existing Mineral Reserves and Resources.
Young Davidson Syenite ? expansion drilling continues to extend gold mineralization beyond Mineral Reserves and Mineral Resources. Exploration spending at Young-Davidson totaled $13.1 million in 2025, including 34,080 m of exploration drilling across 81 holes.
Additionally, 448 m of underground exploration development was completed to establish an exploration drift and drill platforms to the south of the deposit to more effectively test higher grade mineralization defined in the hanging wall. Underground exploration drilling remains focused on two primary areas. The first is continuing to extend mineralization within the Young-Davidson syenite, which hosts the majority of Mineral Reserves and Mineral Resources.
The second is to test and expand on higher grade gold mineralization that has been intersected within two areas of focus in the hanging wall of the deposit. Of the 81 holes drilled in 2025, more than half were completed in the latter part of year and after the cut off date for year-end 2025 Mineral Reserve and Resource reporting. Drilling from the 9305-level and 9440-level in 2025 has been successful in intersecting high-grade gold mineralization within a syenite intrusion in the hanging wall to the southeast of the main Young Davidson Deposit.
This area is 285 m south of the Northgate Shaft and has seen limited historical drilling. Gold mineralization is associated with 3-20% pyrite and occurs both as wide, low- to moderate-grade mineralization, and within narrower, high-grade shear zones and quartz veins. Drilling will continue in 2026 with the objective of further expanding upon the high-grade mineralization where it remains open to the east and up/down dip.
Drilling from the 9620 and 9500 levels is focused on expanding on higher-grade gold mineralization in the hanging wall sediments, syenite, and mafic-ultramafic lithologies that was initially defined in 2024. These zones are located in proximity to existing infrastructure and south of existing Mineral Reserves and Resources. The 2025 drill program was successful in continuing to define and expand a new style of higher-grade mineralization that is hosted in hanging wall stratigraphy including a folded sequence of conglomerates, volcanics, and syenite intrusions.
Higher-grade gold mineralization is associated with 3-15% pyrite and occurs both as wide, low- to moderate-grade mineralization, and within narrower, high-grade structures. In 2025, a 448 m hanging wall exploration drift was established through the hanging wall mineralization, and further to the south to provide additional optimized drill platforms to effectively test the controls, geometry, and continuity of the higher-grade mineralization identified in 2024. Drilling commenced from this hanging wall exploration drift in the third quarter of 2025.
To date, 31 holes have been completed, of which 18 are being reported in this release, and assays are pending for 13 of the holes. Young Davidson Syenite ? expansion drilling from underground drill platforms across the deposit continues to target and successfully extend gold mineralization beyond existing Mineral Reserves and Mineral Resources within the main syenite unit.
Young-Davidson has maintained at least a 13-year Mineral Reserve life since 2011. With the deposit open and depth and to the west, there is excellent potential for the track record to continue.
