Initial exploration in the Valeriano area commenced in the mid to late 1980’s. Early exploration programs focused on exploring for near surface gold and copper mineralization, which was similar to other projects located southward along the El Indio Belt. By 2013, the focus shifted to drilling, which led to the discovery of significant copper-gold porphyry mineralization at depth. Since ATEX became involved in the Project in 2019, six phases of exploration have been conducted.

Phase I – Initial Discovery and Oxide Gold Definition

The initial program established the near-surface oxide gold opportunity and confirmed the presence of copper-gold porphyry mineralization at depth. This work provided the foundation for follow-up drilling of the deeper porphyry system.

Phase II – First Porphyry Test

In 2022, ATEX drilled the first dedicated test of the porphyry system with holes ATXD17 and ATXD19, targeting the Central High-Grade Trend initially identified by historical drilling. Both holes intersected significant mineralization and confirmed the potential for a higher-grade core grading at least 0.8% CuEq.

Phase III – Expansion of the Mineralized Corridor

The 2022–2023 Phase III program introduced directional drilling to extend the porphyry system while reducing the need for new surface drill collars. The program expanded the mineralized corridor, extended the higher-grade core, and identified a third porphyry trend west of the Central Trend. Eight holes also produced the project’s longest intersections to that point.

Phase IV – Improved Geometry and Continuity

The 2023–2024 Phase IV program continued the use of directional drilling and materially improved the understanding of the Valeriano system’s geometry. Drilling demonstrated stronger continuity in the higher-grade core, extended the mineralized intrusive units to more than 1.2 kilometres of strike, and intersected the best grades reported on the project at that time. The system remained open in all directions, while hole ATXD26 discovered the high-grade B2B Zone above the porphyry units, representing potential optionality as a separate high-grade domain within the greater resource envelope and higher up in the system.

Phase V – Expansion of the B2B Zone

The 2024–2025 Phase V program completed approximately 16,600 metres of directional diamond drilling saving ATEX approximately 9,200m of drilling compared to using conventional drilling methods. Phase V confirmed and expanded the B2B high-grade zone, bringing its upper contact to approximately 400 metres below the valley floor. The higher-grade porphyry trend was also extended by more than 200 metres to one kilometre in length and remained open to the north-northwest and southeast.

Phase VI – Further Growth of B2B and the Porphyry Corridor

The 2025–2026 Phase VI program completed approximately 28,400 metres of directional diamond drilling using six rigs. The program extended the B2B Zone by 50% to more than 600 metres of strike and continued to confirm continuity of higher-grade mineralization. It also expanded the broader mineralized porphyry corridor to approximately 1.8 kilometres, with mineralization remaining open along strike and at depth. The combination of repeated high-grade copper-gold intersections, expansion of B2B along strike and at depth, broad mineralized intervals surrounding the breccia and regional drilling that continues to encounter porphyry-related mineralization outside the known system provides a strong foundation for the next phase of exploration.

Table 1 – Phase VI Drill Hole Summary

Notes:
(1) CuEq was calculated using the metal prices and recoveries set out in Notes (2) and (3), consistent with the assumptions used in the 2025 Mineral Resource Estimate (see the Valeriano Technical Report), using the following formula: Cu (%) + 1.04991243188302 x Au (g/t) + 0.00824244819238401 x Ag (g/t) + 0.000357909627766355 x Mo (g/t).
(2) CuEq reported assuming metal prices of US$2,750/oz Au, US$3.80/lb Cu, US$27/oz Ag, and US$22/lb Mo.
(3) CuEq reported assuming recoveries of Cu 94%, Au 95%, Ag 80% and Mo 64%.
(4) Drill holes were composited at a cut-off of 0.3% CuEq.
(5) True widths are unknown except where an interpreted true width is specifically stated.
(6) See press releases dated December 18, 2025, February 12, 2026, March 16, 2026, May 26, 2026, July 8, 2026, and August 26, 2026 for previously released Phase VI drill results.
(7) Drill holes ATXD30 and ATXD36 did not return any significant mineralized intervals based on the 0.3% CuEq cut-off used for the composites.