Saudi Arabian Mining Co (Maaden) has received four bids for a $1 billion contract to build an alumina refinery it has recently retendered, industry sources said on Wednesday.

Maaden retendered after increasing the planned size of the plant to 1.8 million tonnes per year from 1.6 million tpy, they said.

'There were scope changes, new technology, they decided to retender to get better bids,' an industry source said.

US Fluor Corp teamed up with Worley Parsons and Canada's SNC-Lavalin Group Inc joined forces with Hatch to submit their proposals, they said. France's Technip and US Bechtel bid individually.

The due date for bids was December 12, two bidders said.

Maaden aims to award the engineering, procurement, construction management (EPCM) contract by the end of March, two bidders said.

The refinery would be fully operational in the first quarter of 2014, they said.

Rio Tinto said last year it dropped plans to take a 49 per cent stake in the smelter because of the global financial crisis. This has delayed the start-up date by three years.

It initially teamed up with Maaden in 2007 to build the project, which includes a 740,000 tpy aluminium smelter. The refinery would feed the smelter at Ras Azzour and the whole project was expected to cost around $8 billion.

Worley Parsons conducted the front-end engineering and design work (Feed) at the refinery.

Before retendering, Maaden had awarded the EPCM contract to Fluor Corp in late 2008 and valued it at around $1 billion, London-based MEED magazine reported last week.-Reuters