Construction of the expansion at BHP Billiton Ltd.s' (BHP) Worsley alumina refinery in Western Australia state is on schedule with engineering now 85% complete and procurement well-advanced, a company executive said Thursday.

In a presentation posted on the U.K.-listed miner's Web site, Jon Dudas, president of BHP Billiton's aluminum division, said incremental production of alumina from the expansion is set to start from the second quarter of 2011, with the completion of full-project mechanics in the third quarter of that year.

The expansion will add more than 1.1 million metric tons a year of alumina capacity to the existing 3.5-million-tons-a-year refinery.

The multi-fuel cogeneration facility is also on time and on budget, Dudas said.

BHP Billiton has an 86% equity stake in Worsley, which gives it 3.01 million tons of alumina annually. The expansion project will boost BHP Billiton's equity capacity in the refinery by a further 946 tons.

-By Andrea Hotter, Dow Jones Newswires; +44 (0)20 7842 9413; andrea.hotter@dowjones.com