Hudbay Minerals Inc.

13.1 Metallurgical Testing Programs

Historical metallurgical testing was conducted on the East Deposit between 1974 and 2013 by prior operators to support early technical assessments and feasibility reports. These earlier programs provided a preliminary understanding of the deposit, the engineering parameters and metallurgical design established for the current flowsheet and are primarily derived from four subsequent testing campaigns:

• 2014-2016 (East Pit Only): Hudbay engaged Consulting & Expert Process Solutions (XPS) and SGS Canada Inc. (SGS), followed by Base Metallurgical Laboratories (BML), to execute process optimization and bench-scale testing. This work focused on improving correlations between mineralogy, geology, and flotation performance of the East Pit directly supporting the 2017 Technical Report.

• 2021 - 2022 (Copper World Project): Following the discovery of additional deposits on the Western side of the Copper World Project in 2021, Hudbay engaged Kappes, Cassiday & Associates (KCA) Laboratorio Metalúrgico Chapi (Chapi) and SGS to perform mineralogical and metallurgical testing on Peach-Elgin, Broad Top Butte, and East Deposit mineralization. This work was to support the 2022 NI 43-101 Technical Report with the objective of characterising each deposit's mineralogy and metallurgical response to both leaching and flotation.

• 2022 - 2023 (Copper World Project): A comprehensive program was executed by AMinpro, TailPro, Blue Coast Research, SGS, and Glencore Technology to establish engineering design criteria and geometallurgical correlations across the broader Copper World Project. This work formed the metallurgical baseline for the 2023 NI 43-101 Technical Report.

• 2025-2026 (Copper World Project): Additional testing has been completed at BML, SGS, AMinpro, McLelland Labs, Glencore Technology and TailPro to further define, quantify and de-risk mineralogical and metallurgical relationships, ensuring robust validation across all defined mining phases.