Snapshot

Highlights

• High-Sulfidation Epithermal System: Geological mapping confirms advanced argillic alteration and widespread brecciation, indicating a robust high-sulfidation epithermal system at surface.
• High-Grade Surface Samples: Rock sampling returned assays up to 9.31 g/t gold and over 1,000 g/t silver, confirming significant precious metal mineralization.
• Large Alteration Footprint: Mineralization and alteration span a 2,500 m by 500 m corridor, remaining open in all directions.
• Untested Geophysical Anomaly: IP surveys outline a large (600 x 500 m) high-chargeability, low-resistivity anomaly beneath the southern part of the project.
• Tier-One Deposit Potential: Tres Cerros shares key geological characteristics with the Lagunas Norte gold deposit – similar host rocks and structural controls.
• Established Infrastructure: The project is located only 6 km from the past-producing Mallay Mine and camp, providing road access and support facilities.

Geology

Tres Cerros is underlain by Tertiary-age volcanic rocks (rhyolite-andesite flows of the Calipuy Formation) that abut older Cretaceous sandstone units (Chimu Formation). Intense hydrothermal alteration (advanced argillic with silica-clay overprint) extends along a ~2.5 km by 0.5 km trend. Surface mapping and sampling reveal brecciation and quartz-sulfide veining, typical of high-sulfidation epithermal systems.

Structural controls include a north-south fault corridor intersecting east-west fractures, forming breccia zones and stockwork veining. High-grade gold-silver mineralization aligns with these structures. The system is enriched in arsenic, antimony, lead, and mercury. Copper values of 0.3–0.6% and elevated tungsten suggest porphyry/skarn potential.

A strong IP anomaly beneath the southern zone (600 x 500 m) indicates a potential sulphide-rich feeder system at depth.

History

Tres Cerros was initially identified by Buenaventura geologists in 2016. Between 2016–2018, over 500 surface samples confirmed consistent gold and silver values over a 2.5 km trend. Despite strong results, the project saw no drilling.

In 2025, Excellon acquired Tres Cerros as part of the Mallay property package. This marks the first time Tres Cerros is being systematically explored with a dedicated program. The project aligns with Excellon’s strategy to advance high-quality precious metal assets in proven jurisdictions.

2024 Sampling Program

The objective of the 2024 sampling program was to verify the presence of mineralization hosted in fractures and breccias found in outcrop on the Tres Cerros Project and to establish the tenor of that mineralization.

A summary of the recent sampling is highlighted below and in Table 1.

• Gold (Au)
  • High-grade veins: up to 9.313 g/t Au and over 1,000 g/t Ag (assay limit)
  • Multiple lower-grade zones: averaging 0.3–0.7 g/t Au in brecciated outcrops.
• Silver (Ag)
  • Brecciated zones: up to 241.0 g/t Ag in breccia-hosted mineralization.
  • Outcrop continuity: consistent anomalous silver along major structures.
• Copper (Cu)
  • Local hotspots: 0.3%–0.6% Cu associated with chalcopyrite in veins.
  • Vector for deep porphyry: elevated Au, Cu and W values coincide with a prominent IP chargeability anomaly.

Table 1. Assay results from select surface samples collected in December 2024*

* Note: Grab samples are selective representations and the assay results may not necessarily represent true underlying mineralization.

Bx: Breccia, Qtzt: Quartzite

The following selected photos highlight samples that returned anomalous Au and Ag grades at Tres Cerros:

Sample 150639: 0.70m @ 3.10 g/t Au, 365.0 g/t Ag. Quartz-sulfide stockwork hosted in brecciated quartz arenite.

Sample 150640: 0.50m @ 3.71 g/t Au, 23.0 g/t Ag. Quartz-sulfide vein hosted in tension fracture through finely bedded quartz arenite. Sample trench filled and hand samples from vein placed across vein width.

Panel sample (1.0 x 1.0 m) on brecciated quartz arenite outcrop. Sample 150628: 0.729 g/t Au, 2 g/t Ag.

Location

Tres Cerros is located in the Andes of north-central Peru, about 180 km north of Lima. It sits 11 km west of the town of Oyón and 6 km west of the past-producing Mallay Mine. The project is accessible by road and benefits from nearby infrastructure including a camp, roads, and power.

Exploration can be supported from Mallay’s existing camp and core facilities. The proximity to infrastructure enables low-cost, year-round exploration and efficient logistics for future drilling.