Banaba, formerly known as Ocean Island, is a solitary raised coral island west of the Gilbert Island Chain, lying 450 km southwest of Tarawa and 300 km east of Nauru, its nearest neighbour. Like other raised atolls (like Nauru), the interior of this atoll contained high-grade phosphate rock (petrified guano), and between 1900 and 1975, 90% of its surface was stripped away. After 1945, the British authorities at the time deported most of the population to Rabi Island in Fiji, a process that continued until 1983; the Banabans founded villages there with the same names as the four they had left behind. Some islanders have returned after mining finished in 1979. The total population is now about 330.