Boliden Zinc Output Surge Reshapes Its 2025 Base Metals Profile

Boliden

Boliden zinc output surge became the clearest feature of the group’s 2025 performance. The company sharply increased mined zinc, while copper also moved higher and nickel stayed broadly stable. Asset restarts and acquisitions drove much of the change. As a result, Boliden zinc output surge has reshaped the company’s base metals profile.

The zinc growth was especially strong. Zinc-in-concentrate production rose 114pc year on year to 350,764t in 2025. The restart of Tara and the additions of Somincor and Zinkgruvan were the main drivers. Therefore, Boliden zinc output surge reflects both portfolio expansion and improved operating availability.

Refined output, however, showed a different pattern. Refined zinc metal production rose only 1pc to 457,345t. That more modest gain highlights the difference between mine growth and smelter expansion timing. Meanwhile, the Odda zinc expansion continued ramping up and supported stronger output in Norway.

Boliden Copper Production Improved, but Smelter Conditions Stayed Mixed

Boliden copper production also improved in 2025, although the gain was smaller than zinc. Copper-in-concentrate output increased 15pc to 104,400t. Somincor contributed added volumes, while Aitik improved later in the year. As a result, Boliden copper production ended the year on a firmer footing.

Aitik’s recovery is particularly important for the 2026 outlook. Copper grades improved toward the end of 2025 after earlier weakness. The company now expects better grades in the second half of 2026, along with higher throughput. Therefore, Aitik remains a key swing factor for Boliden copper production.

Refined copper performance stayed more stable than mined output. Copper cathode production rose 2pc to 162,329t, supported by strong performance at Harjavalta. Copper anode production remained broadly flat, although Ronnskar faced maintenance and operational disruption in the fourth quarter. Consequently, copper smelting conditions remain less straightforward than the mined copper recovery suggests.

Odda Zinc Expansion and Precious Metals Support the 2026 Outlook

The Odda zinc expansion remains one of Boliden’s most important operational themes. Output at Odda rose 10pc to 167,136t in 2025 as the smelter continued ramp-up. Hot commissioning is still ongoing, and new leach product volumes continue to increase. Therefore, Odda could remain a meaningful growth lever into 2026.

Nickel was the weaker area on the refining side. Nickel-in-concentrate output edged up 1pc to 11,627t, but refined nickel matte output at Harjavalta fell 16pc to 33,551t. Process disturbances and maintenance weighed on performance. As a result, Boliden nickel output looked stable upstream but weaker downstream.

The broader margin picture may depend increasingly on by-products. Boliden said stronger gold and silver prices were an important earnings driver in late 2025. That support is expected to remain relevant for smelter margins going forward. Meanwhile, planned 2026 maintenance shutdowns are expected to reduce operating profit, which makes precious metals support even more important.

The Metalnomist Commentary

Boliden’s 2025 result shows how much portfolio structure can change a miner’s growth profile in a single year. Zinc was the headline winner, but the deeper story is that smelter margins may depend as much on by-products and execution as on base metal volume. If Odda and Aitik continue improving, Boliden could enter 2026 with a stronger operating mix than the market first assumes.