Don Elder has resigned as chief executive of Solid Energy, effective immediately, the state-owned coal company said in a statement.
Solid Energy said Elder would remain available to work for the company to assist with a transition.
Elder said that as the company worked its way out of the major global market downturn in 2012, including significant restructuring, the board would consider many future changes.
He believed it was appropriate, and the right time, for the future direction of the company to be led by a new chief executive.
Chairman Mark Ford said that Solid Energy had grown substantially under Elder's leadership since 2000.
Garry Diack, Solid Energy's group manager organisational development and performance, will stand in as chief executive until an appointment is made.
Elder drew flak last year for drawing a big salary while Solid Energy went through a large scale restructuring, which involved the axing of a quarter of its staff.
Read the full statement from Solid Energy here.