Ivanhoe to make $1.8 bln rights offering

May 23 (Reuters) - Ivanhoe Mines , an affiliate of giant mining company Rio Tinto , said on Wednesday it intends to launch a rights offering open to all its existing shareholders that would raise about $1.8 billion in proceeds.

The rights offering, in which all Ivanhoe shareholders could participate, is part of a comprehensive financing plan to continue the development of the Oyu Tolgoi copper-gold project in Mongolia, the company said.

Anglo-Australian miner Rio Tinto earlier this year acquired a controlling interest in Vancouver-based Ivanhoe, whose main asset is the massive Oyu Tolgoi project.

Rio, which owns a 51 percent stake in Ivanhoe, said it plans to buy the maximum number of shares it is permitted to acquire under the terms of the rights offering. (Reporting By Euan Rocha; Editing by Gerald E. McCormick)