Diversified mining group Rio Tinto has welcomed Australia's decision to re-examine allowing third parties on a rail network in the Pilbara region which the miner believes could seriously affect its operations.

Rio said in a statement on Friday morning: "The High Court of Australia has held that the Full Court of the Federal Court of Australia, in deciding not to declare the Hamersley and Robe rail lines, wrongly endorsed consideration by the Australian Competition Tribunal of material it was not entitled to take into account."

As such, the High Court has remitted the matter back to the Tribunal to "re-determine the matter".

"The Minister and the Tribunal both applied the wrong test in determining this threshold issue, and the Tribunal will be bound to adopt the test Rio Tinto argued for on any reconsideration."

Rio said that its integrated operations in the Pilbara would be "severely impacted" if third parties were allowed to run trains on the systems.

It is reported that other miners, such as Fortescue Metals Group, would be able to access the rail system if the decision goes ahead.

"As the Tribunal noted, the potential disruption and diseconomy costs would dwarf whatever benefits might exist in permitting third party access," Rio said.

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