PORTMAN Ltd has appointed Joseph Carrabba as chairman and chief executive officer following the resignation of John Brinzo. Mr Carrabba, a former Rio Tinto executive, was the president and chief operating officer of Cleveland Cliffs before the appointment. Mr. Carrabba previously served as president and chief operating officer of Diavik Diamond Mines Inc and general manager of the Weipa Bauxite Operation of Comalco Aluminum.