The head of Western Australia's Economic Regulation Authority says the two parties involved in a dispute over rail access in the Pilbara must 'be grown up' enough to reach an agreement.
Junior miner, Brockman Resources has applied to use Fortescue Metals Group's railway to haul 20-million-tonnes of iron ore a year from its mine to port.
The railway falls under FMG's infrastructure arm, The Pilbara Infrastructure.
Under a state agreement it signed, FMG is obliged to negotiate access with third parties
But it is fighting Brockman's proposal saying it has no spare capacity on its railway.
The ERA's Lyndon Rowe says his job is to rule on a fair price for access and that the issue will go to court if no agreement is reached.
"Our decision on TPI's floor on ceiling prices will be released before Friday," he said.
"The Institute of Arbitrators have given us a panel of names from which we can choose to appoint an arbitrator.
"The arbitrator will arbitrate within those floor and ceiling costs boundaries.
"Apart from that the parties have to be grown up enough to come to their own conclusions."