Companies such as Glencore have come under pressure from investors to cut debt amid a broadranging slump in commodity prices.
Nakazato said Sumitomo Metal was sticking with a long-term goal to boost its annual copper output from the mines in which it holds a stake to 300,000 tonnes in 2021, up from planned output of 175,000 tonnes this year.
Sumitomo Metal was also unlikely to reach full capacity at its Sierra Gorda copper mine in Chile until April or May, he said, confirming indications from another company official last week that the schedule would be delayed from December.
The delay was due to problems with the mine's molybdenum plant, he said.
The Sierra Gorda mine, owned jointly with Polish producer KGHM Polska Miedz, began commercial production at the end of June and the setback adds to a slew of production delays at Chilean copper mines this year.
While its basic finances are healthy, Japan's second-biggest copper producer still slashed its full-year profit forecast this month, blaming the plunge in the prices of copper and nickel and the delayed ramp-up at Sierra Gorda. (Reporting by Yuka Obayashi; Editing by Aaron Sheldrick and Richard Pullin)
