Gladstone community members, local indigenous leaders and Queensland Premier Campbell Newman joined more than 600 Rio employees at the opening of the expansion today which will double production at the refinery to 3.4 million tonnes of alumina per annum.

Rio Tinto Alcan bauxite and alumina president and chief executive officer Pat Fiore said the opening highlighted how the Yarwun expansion strengthened the economic, cultural and social ties between Gladstone and Western Cape York Peninsula.

"Together, Rio Tinto Alcan's Queensland operations and our Weipa bauxite mining operations employ approximately 3000 people and are mainstays of these important regional communities," he said.

With the opening of the Yarwun refinery, 250 additional jobs for Gladstone locals have been created.

Fiore said Rio would reap the benefits of the refinery's expansion.

"The commissioning of the refinery expansion allows additional volumes of bauxite to be processed more efficiently, at a lower cost," he said.

"This means the expanded operations will improve operating costs for the entire Yarwun refinery and the bauxite and alumina portfolio."

The expansion, which has been in the works since 2007, experienced volatile conditions following the onset of the global financial crisis.

"The project team successfully responded to these challenges and consistently delivered reliable assets safely, on time and on budget," Fiore said.

During the construction period, $1.9 billion was spent on contract and procurement in Australia, including $360 million in Gladstone and $1.4 billion in Queensland.

The expanded refinery is currently running at about 90% capacity.

Fiore said the key focus for the remainder of the year was to bring the expanded facility safely into stable operations to increase the plant's capacity to full production next year.