Rio Tinto bauxite and alumina chief Phillip Strachan steps down

The man in charge of Rio Tinto's $US1.9 billion ($2.7 billion) bauxite expansion has left the company, as the miner's cost cutting drive continues to trim its executive ranks.

Phillip Strachan had been Rio's chief executive of Bauxite and Alumina based out of Brisbane in recent years, but his role will now be absorbed by Pacific Aluminium chief executive Bruce Cox.

The change comes barely three months after Rio announced it would go ahead with a major expansion of its bauxite export business near Weipa in Queensland.

Mr Strachan has been involved with Rio's aluminium division since 1999, and it is believed he is not the only departure from Rio's Brisbane office.

Mr Cox is well known across the Australian mining sector, having spent more than three decades working for BHP Billiton and Rio Tinto in a range of roles across iron ore, copper, diamonds, steel and most recently aluminium.

A product of Wollongong, Mr Cox has been head of Pacific Aluminium - the group of Australasian aluminium smelters that Rio tried to sell in 2012 - since September 2013. Pacific Aluminium includes the Bell Bay smelter in Tasmania, the Boyne Smelter near Gladstone, the Tomago smelter in New South Wales and a fourth smelter in New Zealand.

The changes to the bauxite division come barely a year after the head of Rio's energy division, Harry Kenyon-Slaney, left the Brisbane office and the company entirely. That change saw Rio's ever diminishing coal business put into the same division as copper under the stewardship of Jean-Sebastien Jacques.

Despite the senior executives leaving the Brisbane office, Rio still has a fairly significant presence in the city, with much of the procurement work for the Oyu Tolgoi project in Mongolia being conducted from Brisbane. nBrisbane is also home to Rio's "processing excellence centre", where a team monitors and communicates directly to operations all over the world.