The European Commission has informed Australian iron ore miners BHP Billiton PLC (BHP) and Rio Tinto Ltd. (RTP) about the state of its investigation into the proposed joint venture between the two companies, a spokeswoman said Friday.

The commission's competition staff has "informed the parties during a state-of-play meeting today about the results of the preliminary investigation," said Amelia Torres, spokeswoman for Competition Commissioner Joaquin Almunia.

The commission hasn't yet sent the companies a formal letter to outline its concerns, she explained.

In January, the commission, the European Union's antitrust body, opened an investigation into the JV, citing concerns that the deal might have harmful effects on price competition in the worldwide market for iron ore transported by sea.

Clearance from the EU's competition regulator is seen as the biggest potential hurdle to the joint venture, which failed in its initial form in 2008.

Rio Tinto and BHP Billiton are, respectively, the second- and third-largest producers of iron ore in the world, after Brazil's Vale SA, the commission said.

-By Alessandro Torello, Dow Jones Newswires; +32 2 741 14 88; alessandro.torello@dowjones.com