Nauru is a phosphate-rock island with rich deposits near the surface, which allowed easy strip mining operations. Its remaining phosphate resources are not economically viable for extraction. Since the phosphate reserves were exhausted in the 1990s, and the island's environment has been seriously harmed by mining, the trust established to manage the island's wealth has diminished in value. To earn income, Nauru briefly became a tax haven and illegal money laundering centre. From 2001 to 2008, and again from 2012, it accepted aid from the Australian Government in exchange for hosting the Nauru Regional Processing Centre, a controversial offshore Australian immigration detention facility. As a result of heavy dependence on Australia, some sources have identified Nauru as a client state of Australia. The sovereign state is a member of the United Nations, Commonwealth of Nations and the African, Caribbean, and Pacific Group of States.