In September 2000 a ‘class action' was filed in California in the USA claiming unspecified damages against Rio Tinto Limited and Rio Tinto plc arising from mining operations at Panguna, Bougainville and the civil unrest leading to and following mine closure. BCL was not a party to this action but followed developments closely. Rio Tinto Limited is BCL's largest shareholder (the nest largest being the Papua New Guinea Government ). Rio Tinto plc is not a shareholder in BCL. Both defendants believe the claims to be wholly without merit and indicated their intention to defend them vigorously. The case had wider implications for PNG investment if conduct relating to business solely in Papua New Guinea can be litigated on a contingency fee base in the USA .

The claims relate largely to acts of the PNG Government. Rio Tinto is alleged to have ‘partnered' the Government in the project and, as a consequence, is alleged to be vicariously liable for the alleged wrong doings. Rio Tinto has denied liability.

The court of first instance dismissed the action and an appeal was heard in 2003. The appeal court has given the parties notice a decision will not be given until the US Supreme Court hears another case, with some common legal questions, later this year. The appeal decision may not be the end of the matter because further appeal processes are available. BCL is not a party to any litigation in the USA .

In 2001 BCL was a defendant to an action commenced in the National Court of Papua New guinea by two plaintiffs seeking declarations that they are the lawful representatives of mine site and tailings disposal area landowners and that the Mining Warden is the proper judicial officer to determine what, if any, compensation is due to landowners for the period since the mine close. BCL made a provision in its accounts to cover an award of landowner compensation.