TOKYO/MELBOURNE, July 16 (Reuters) - Indonesian copper smelter Gresik has shut down due to a technical problem and it is not clear when the smelter will reopen, a spokesman at majority owner Mitsubishi Materials Corp said on Thursday.
Takuya Kitamura said that the shutdown at the smelter was due to a broken pipe system, but he was not able to give a timetable for how long the outage would last.
Mitsubishi Materials owns 60.5 percent of the operator of the facility, PT Smelting. The Indonesian unit of U.S.-based Freeport-McMoRan Inc holds a 25 percent stake.
Two sources with knowledge of the shutdown said the plant has already been shut for several weeks, and that they expected the closure to last for at least one more.
The Gresik smelter produced 230,000 tonnes of refined copper last year running at about 75 percent of its capacity.
"They were hoping to get it fixed, but they couldn't. Another week or so and it would nearly be a month," said a trader in Asia.
"It hasn't hurt them too much because of the slowdown in Indonesia, during Ramadan, when people tend to push back on deliveries. Still, it's gone on long enough now that ... it probably will affect deliveries."
Kitamura was not able to say whether the company was looking for alternatives for themselves or their customers for sourcing replacement supply.
Traders said that customers were unlikely to be hurt, since PT Smelting could easily buy metal from an amply supplied spot market to replace any contracted shipments.
Other stakeholders in PT Smelting are Mitsubishi Corp with 9.5 percent, and Nippon Mining and Metals, a unit of Nippon Mining Holdings, with 5 percent.
(Reporting by Osamu Tsukimori in TOKYO, Melanie Burton in MELBOURNE and Randy Fabi in JAKARTA; Editing by Tom Hogue)