BHP Billiton chair Don Argus said the group's decision to drop its plans to pursue rival Rio Tinto is "disappointing after many months of hard work".

Canada's Platinum Group Metals is scouting for more mining rights in South Africa, the world's top platinum producer, and is seeking permits to start construction at its existing projects in the country. "We have been very actively looking in South Africa," R Michael Jones, president and chief executive of the company, said on Thursday.