Rio to beef up board Rio Tinto will look to add as many as three new directors to its board over the next 12 months, according to company chairman Jan du Plessis. Speaking at Rio's annual meeting of Australian shareholders in Sydney this morning, Mr du Plessis accepted criticism that his board needed more mining experience, and said the issue should be addressed soon. "I really am hoping that we will invite another two, maybe three, new directors on to the board over the next year," he said. Mr du Plessis added that he expects at least "one of those to have mining experience." The level of mining experience on the Rio Tinto board has become a hot topic over the past fifteen months as the company racked up more than $US20 billion in impairments on investments made in aluminium and coal. Proxy advisors CGI Glass Lewis have also complained about the lack of mining experience on the board. But Mr du Plessis noted that he was pleased that new chief executive Sam Walsh, and new chief financial officer Chris Lynch both had significant experience in running mining operations. One shareholder agreed, describing the pair thus; "They haven't got cholesterol in their blood, they've got minerals." Mr du Plessis was asked by shareholders why numerous directors were allowed to continue on the board despite serving through the disastrous $US38 billion Alcan acquisition in 2007. Mr du Plessis said all directors involved in that investment were ""embarrassed"" at how it had turned out, with about 75 per cent of that value now lost through impairments.But Mr du Plessis said all those directors were better for the experience. ""Having been involved in that, we've learned from that,"" he said. Mr du Plessis added that by the end of 2014, only ""one or two"" of the directors present during the Alcan purchase were likely to still be serving on the board. One director singled out by shareholders was Lord Kerr of Kinlochard, a former head of the British diplomatic service. Lord Kerr has served on the Rio board for ten years and was also targeted by the Australian Shareholders Association as being ripe for removal. But Mr du Plessis revealed that Lord Kerr had sought to retire from the board, but had been asked to stay on. Mr du Plessis said Lord Kerr was particularly valuable to the company given his knowledge of geopolitical matters. ""He is a valuable, valuable director... he has agreed to serve another year at our request,"" he said. Speaking to reporters after the conclusion of the AGM, Mr du Plessis said he hoped one of the new directors appointed over the next 12 months would be an Australian citizen.