Robe River is a joint venture between Rio Tinto, Mitsui, Nippon Steel and Sumitomo Metal Industries that operates in Western Australia's Pilbara.
Robe first asked WA's Environmental Protection Authority for permission to expand its existing Mesa A/Warramboo iron ore project late in 2016.
The proposal went to the EPA, which decided to assess at the level of public environmental review with a two-week public review period and an EPA prepared environmental scoping document.
However, before the EPA could assess Robe applied to change its proposal, which has been granted.
The proposal involves developing mine pits and associated infrastructure and water treatment and processing facilities.
Existing mine pits and waste dumps will also be expanded.