NEW YORK, May 17 -- Century Aluminum Co (CENX.O: Quote) said this week that contract talks were continuing with union representatives of its Century Aluminum of Kentucky subsidiary.

Company management and United Steelworkers of America union have been negotiating over a new labor contract covering approximately 500 hourly workers at the Hawesville aluminum smelter, with capacity of about 244,000 tonnes per year.

The agreement, originally scheduled to expire on March 31, had been extended through May 7, but ended without further extension. The agreement had been extended three times previously.

As negotiations between the two parties continue, employees remain on the job and the plant is operating normally, a company statement said.

"We continue to work towards an agreement that serves the best interests of all of our constituents," said Hawesville plant manager Matt Powell.

Union representatives were not immediately available. But the two sides were said to be near reaching a deal.

Monterey, California-based Century Aluminum owns primary aluminum facilities in the United States and Iceland.