Nauru became self-governing in January 1966, and following a two-year constitutional convention, it became independent on 31 January 1968 under founding president Hammer DeRoburt. In 1967, the people of Nauru purchased the assets of the British Phosphate Commissioners, and in June 1970 control passed to the locally owned Nauru Phosphate Corporation (NPC). Income from the mines made Nauruans among the richest people in the world. In 1989, Nauru took legal action against Australia in the International Court of Justice over Australia's administration of the island, in particular, Australia's failure to remedy the environmental damage caused by phosphate mining. ''Certain Phosphate Lands: Nauru v. Australia'' led to an out-of-court settlement to rehabilitate the mined-out areas of Nauru.