Fortescue Metals Group has lost its second operations director in a year, with David Woodall quitting the iron ore major yesterday.
Mr Woodall was appointed in January. His predecessor, Jamie Franklyn, was also in the role for only a year.
The departure comes at a critical time for Fortescue, which recently shipped first ore from its Kings mine and is racing to ramp up production to a rate of 155 million tonnes a year by March.
It is unclear what triggered Mr Woodall's departure. Fortescue has maintained it will hit its target export rate on time, and there has been no change to its cost or production guidance at its other operations.
Fortescue's annual report showed Mr Woodall was awarded 66 per cent of his possible short-term cash bonus for 2012-13, only a little below the 70 per cent to 74 per cent of cash bonus maximums awarded to other senior executives.
Fortescue said Mr Woodall had resigned to "pursue other opportunities", and the former operations director had been "instrumental in improving our technical and mine planning areas".
"A process is under way to fill his position," chief executive Nev Power said. "In the meantime, the depth of experience in Fortescue's management team assures a smooth transition throughout this period."
Shares in Fortescue closed unchanged yesterday at $5.36.