COSE (Cap-Oeste Sur East)

San Luis is a district-scale high-grade gold-silver project owned and operated by Highlander Silver and located in the Ancash

Department in central Peru. A historical feasibility study on the

San Luis project was completed in the second quarter of 2010, outlining a 3.5 year underground mine plan focused on the highgrade silver-gold Ayelén vein, which remains open in multiple directions. In 2025, Highlander Silver released an updated Mineral

Resource estimate based on historical drilling, outlining 356 koz of gold and 8.4 Moz of silver in the Indicated category.

Highlander Silver expects to drill multiple targets to support future growth on the 23,098 hectare property, including Gemelas, Carhuan-Puquio and La Bonita. Drilling at La Bonita began in 2025, where Highlander Silver reported broad near-surface gold-silver mineralization and expects the target to support a conceptual open pit opportunity approximately 10 km south of

Ayelén. Recent drilling at San Luis returned 23.9 meters at 20.82 g/t gold and 31.53 g/t silver and 23.4 meters at 11.70 g/t gold and 26.10 g/t silver from shallow drilling, while step-out drilling at La

Bonita returned 24.8 meters at 7.43 g/t Au and 16.45 g/t Ag and 40.4 meters at 3.42 g/t Au and 16.93 g/t Ag.

Metalla holds a 1.0% NSR royalty on San Luis.