TIMELINE: BHP Billiton bid for Rio Tinto

(Reuters) - BHP Billiton (BLT.L) (BHP.AX) launched a formal bid for rival Rio Tinto (RIO.L)(RIO.AX) on Wednesday, offering 3.4 of its shares for every Rio share.

Following is a chronology of the bid.

November 8, 2007 - BHP, the world's biggest mining group, proposes to buy Rio through a three-for-one share swap, sending Rio shares soaring as much as 30 percent. Rio rejects the proposal as vastly undervaluing the firm and its prospects.

November 12 - BHP gives details of its takeover plan, arguing the marriage would result in $3.7 billion in synergies in seven years and promises to hand back $30 billion to shareholders via a share buyback if the deal goes through. Rio says the bid remains "well out of the ballpark".

November 14 - Aluminum Corp of China Ltd. (Chalco) (2600.HK) (601600.SS) says it is worried about BHP's bid.

November 20 - China's steel industry, the world's largest, is deeply concerned about a proposed merger of BHP and Rio, a Chinese state newspaper reports. Eurofer, the lobby group for the European steel industry, said it will ask the European Commission to block the proposed merger.

November 26 - Rio says it does not need BHP's offer, unveiling plans to double iron ore output by 2018, raise its dividend and generate at least $15 billion in asset sales.

November 27 - Seven banks pledge to raise $70 billion of financing for BHP's planned bid.

December 4 - A Chinese newspaper says China's top steelmaker, Baosteel, may bid for Rio, but later the firm denies the report.

December 7 - Rio says the firm had been approached with offers from other suitors, but has not engaged with them and was sticking with its independent growth strategy.

December 11 - Rio asks Britain's Takeover Panel to set a deadline under its "put up or shut up" rule under which BHP has to formalize its bid or walk away.

December 21 - Britain's Takeover Panel imposes a deadline of February 6 for BHP to make a formal bid for Rio or abandon bid for six months.

January 25, 2008 - Rio CEO reiterates BHP bid is too low, saying it was "two ballparks away" from fair value.

February 1 - Aluminum Corp of China (Chinalco) and Alcoa (AA.N) say they bought a 9 percent stake in Rio worth $14 billion. They say they do not currently intend to make an offer for Rio, but reserve the right to do so in the future.

February 6 - BHP announces formal bid, sweetening offer to 3.4 shares for each Rio share and setting 50 percent acceptance level.

(Reporting by Eric Onstad)