The buyer is a consortium of Japanese companies comprising Nippon Steel Corporation, Mitsui & Co, Nippon Steel Trading Corporation, Shinsho Corporation and JFE Mineral Co.

It is the same consortium that owns 12% of the adjoining Moranbah North project.

Grosvenor, which started production in 2016, uses Moranbah North's processing infrastructure.

"The alignment of ownership interests across the Moranbah-Grosvenor operation is an important step forward as we unlock the considerable additional value that we see," Anglo Bulk Commodities CEO Seamus French said.

"Our ability to expand the plant, debottleneck various processes, and have the flexibility to blend our naturally high quality products more effectively, all support the long term competitiveness of what is already a world-class asset.

"I am pleased to be building on the successful relationships with our joint venture partners in delivering Moranbah-Grosvenor's full potential for the benefit of all our stakeholders."

A $300-400 million expansion to add 4-6 million tonnes per annum of capacity at the complex is being targeted for approval by mid-2020.