Ivanhoe Mines (IVN -2.7%) says it will launch a rights offering open to all its existing shareholders that would raise ~$1.8B in proceeds as part of its plan to finance development of the Oyu Tolgoi copper-gold project in Mongolia. Rio Tinto (RIO -2.9%), which owns 51% of IVN, plans to buy the maximum shares permitted by the terms of the offering.