Mitsubishi Materials to end some Onahama smelter operations by end-March 2027 (updated)

Mitsubishi Materials

25/03/2026 09:14

Adds details from paragraph 2

By Yuka Obayashi

TOKYO, March 25 (Reuters) - Mitsubishi Materials 5711.T said on Wednesday it will stop processing copper concentrate and operating related smelting facilities at its Onahama plant by the end of March 2027.

Intensifying competition from overseas smelters and a sharp deterioration in treatment and refining charges (TC/RCs) for copper concentrate had made the business outlook increasingly uncertain, Mitsubishi Materials said in a statement.

It expects to book an impairment loss of 21 billion yen ($132 million) in the fourth quarter of the financial year ending this month, mainly tied to the smelter's fixed assets.

TC/RCs, fees paid by miners to turn concentrate into refined metal, have come under pressure as global smelting capacity, led by China, expands faster than mined supply, squeezing margins.

While Onahama has sought to remain profitable by suspending some processes, cutting concentrate processing and reducing costs, Mitsubishi Materials decided as part of a structural overhaul to halt concentrate processing and related smelting equipment at the plant, which has operated since 1965.

The electrolytic plant will continue to refine the group’s copper anodes and scrap‑derived anodes. Other facilities, including the platinum group metals recycling plant and the foundry producing copper ingots, will also continue operating.

Japanese copper smelters are grappling with tumbling TC/RCs and shrinking smelting margins.

With the aim of boosting profitability, JX Advanced Metals 5016.T, its partners and Mitsubishi Materials said in November they plan to integrate Mitsubishi Material's copper concentrates procurement and copper product sales into Pan Pacific Copper.        ($1 = 159.0300 yen)

 (Reporting by Yuka Obayashi; Editing by Christian Schmollinger and Alexander Smith)

 ((Yuka.Obayashi@thomsonreuters.com; +813-4520-1265;))