Development at the Aquila site, which is part of Anglo's 6.5mn t/yr Capcoal mining complex in the Bowen Basin, will begin in September with longwall production of premium hard coking coal to follow in early 2022.
"Aquila offers us a high margin six-year life extension to our Grasstree mine, with an average annual saleable production of 3.5mn t of premium quality hard coking coal," said the company's chief executive of bulk commodities Seamus French.
The Grasstree mine produces the German Creek premium low-vol hard coking coal brand.
The Aquila expansion project still needs to be approved by Japanese conglomerate Mitsui, which owns 30pc of Grasstree. Anglo owns the remaining 70pc of the mine.