MELBOURNE, Dec 2 (Reuters) - Alcoa Corp was forced to shut one of two potlines at its Portland aluminium smelter in Australia following a power outage on Thursday and does not know when it will be restarted, a spokesman said on Friday.
The plant was hit when a power interconnector between the states of Victoria and South Australia went down, knocking out power to both of the smelter's potlines for about five and a half hours.
"As a result of the outage and subsequent instability, and to ensure the safety of people inside the plant, one potline has been curtailed. Efforts are focussed on maintaining production in the smelter's second potline," Alcoa said in a statement.
"It is too early to speculate on the full impact of the power outage, or on how long it may take to restore normal operations."
The Portland smelter, co-owned by Alcoa, CITIC and an arm of Marubeni Corp, produces about 300,000 tonnes of aluminium a year.
Reporting by Sonali Paul; Editing by Richard Pullin