Newly-merged commodities trader and mining giant Glencore Xstrata has appointed three new senior directors, including the former Chief Executive Officer (CEO) of US banking titan Morgan Stanley.The company said on Wednesday that John Mack, former frontman and Chairman of Morgan Stanley and ex co-CEO of Credit Suisse, would be appointed to the board as an Independent Non-Executive Director.Joining him is Peter Grauer, Chairman and former CEO of financial media firm Bloomberg.Meanwhile, Peter Coates, already a senior executive of Glencore Xstrata, is to be made an Executive Director. He was previously CEO of Xstrata's coal business before the merger."The board is extremely pleased to be able to move forward with the appointment of three additional directors," said Interim Chairman Tony Hayward, himself the former CEO of oil major BP."Each of them has an excellent business track record and extensive international experience, which we believe will prove invaluable in continuing the strength of debate and challenge which has typified the operation of the company's board since its initial public offering two years ago."