Equity Trustees Ltd will manage the distribution of these shares between the Autonomous Bougainville Government and Papua New Guinea.
Under the trust deed, the ABG has the opportunity to receive 68% of Rio Tinto's shareholding (which equates to 36.4% of BCL's shares) from the independent trustee for no consideration and PNG is entitled to the remaining 32% (which equates to 17.4% of BCL's shares).
The ABG and PNG will both hold an equal share in BCL of 36.4% if the transfers are completed.
This ensures both parties are equally involved in any consideration and decision-making around the future of the Panguna mine.
Rio Tinto copper coal chief executive Chris Salisbury said that his company's review looked at a broad range of options and by distributing our shares in this way we aim to provide landowners, those closest to the mine, and all the people of Bougainville a greater say in the future of Panguna.
"The ultimate distribution of our shares also provides a platform for the ABG and PNG government to work together on future options for the resource."
In accordance with the existing management agreement with BCL, Rio Tinto will today give the required six months' notice to terminate the arrangement.
Rio said that even though it would no longer hold any interest in BCL, it would continue to meet its obligations under the agreement during the period to ensure an orderly transition in the shareholdings of the company.
BCL 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.