[3] The McArthur River has significance for the local Aboriginal communities, who use it for fishing and other traditional activities.

The estuary is in near-pristine condition,[8] and forms part of the Port McArthur Tidal Wetlands System Important Bird Area.

[10] Traditional owners were concerned the proposal, which included a 5.5 km (3.4 mi) river diversion, had serious, long term and irreversible impacts.

[12] In early 2009, the Federal Environment Minister Peter Garrett formally approved the mine's expansion.

[4][13] Garrett placed conditions on the project which aimed to reduce the impact on the freshwater sawfish and migratory birds.