The dispute over whether Rio Tinto should allow third-party access to its rail lines serving its Pilbara iron ore asset rumbles on, with the granting of an appeal against the Federal Court of Australia's verdict that Rio could exclude others from using it.The High Court of Australia has granted Fortescue Metals Group and the National Competition Council leave to pursue appeals in relation to the decision earlier this year of the Full Federal Court to deny third party access to Rio Tinto's Hamersley and Robe River rail lines. Rio Tinto had argued that the potential costs of access far exceed any theoretical benefits, and still maintains this belief.No date has been set for the hearing of these appeals but it is expected that they will be listed in the first half of 2012, a statement from Rio said.Rio Tinto will take all appropriate steps to defend these appeals. --jh