Hudbay Minerals Inc.

25.2 Open Pit Mining

In the Base Case, the mining sequence considers the exploitation of the pits and their associated infrastructure over a footprint expected to require only state and local permits for 15 years (plus two years of pre-stripping). During this period, all waste, tailings, and low-grade stockpiles are also disposed of within the perimeter of Hudbay's private land properties.

In this Base Case, 390 million tonnes of concentrator feed and approximately 589 million tonnes of waste will be extracted, yielding a life of mine stripping ratio of 1.5 (including pre-stripping material).

An important constraint on the mine production schedule is the limited space for disposing of waste rocks, tailings, and low-grade stockpiles, resulting in a sub-optimum mining sequence from a strict economic standpoint. However, the current mine plan allows the mine to operate in a sustainable manner for 15 years. Securing Federal permits earlier would unlock significant benefits to the project by removing these important constraints on the mining schedule and likely allow more tons and/or better grades to be mined earlier than currently planned. This is illustrated in the Extension Case which has assumed that mining activities could progress onto Federal land in Year 10.