A planned iron ore joint venture between Rio Tinto Ltd. (RTP) and BHP Billiton Ltd. (BHP.AU) in the Pilbara region of Western Australia state will result in the loss of hundreds of jobs, a trade union said Friday.

The Australian Manufacturing Workers Union's Western Australian State Secretary Steve McCartney said workers should be worried by the miner's plans to extract US$10 billion in cost savings from the deal.

"This can only mean that hundreds, maybe thousands, more local jobs will go when this merger happens," he said.

"They are talking about using the same rail lines and joining together adjacent mines, which will no doubt lead to a mass clear out of train drivers, miners and other specialized trades people at the various BHP and Rio Tinto iron ore facilities in the Pilbara."

-By Alex Wilson, Dow Jones Newswires; 61-3-9292-2094; alex.wilson@dowjones.com