Papua New Guinea and Autonomous Bougainville Government agreed to acquire 53.8% stake in Bougainville Copper Ltd. (ASX:BOC) from Rio Tinto Group (LSE:RIO) for no consideration on June 30, 2016. Autonomous Bougainville Government will acquire 68% of Rio Tinto's shareholding, which equates to 36.4% of Bougainville Copper's shares and Papua New Guinea will acquire 32%, which equates to 17.2% stake in Bougainville Copper. Post-completion, Autonomous Bougainville Government and Papua New Guinea will both hold an equal share of 36.4% stake in in Bougainville Copper.

Rio Tinto has transferred the stake to a trustee and will no longer hold any interest in BCL, but Rio Tinto will continue to meet its obligations under the agreement during that transition period. Bougainville Copper's Chairman Peter Taylor will resign with immediate effect but he will continue to be available to provide services to the Board during this transition period. Equity Trustees Limited will manage the distribution of the shares between the Autonomous Bougainville Government for the benefit of all the Panguna landowners and the people of Bougainville, and the Independent State of Papua New Guinea.

As of July 4, 2016, Bougainville Copper announced that the Management Agreement entered into with Rio Tinto has been terminated and The Independent State of Papua New Guinea has taken up its 17.4% entitlement to Bougainville Copper Limited shares under the arrangements established by Rio Tinto.