Mining giant Rio Tinto said it is in talks with several of its iron ore customers about moving to quarterly pricing of iron ore contracts.The move comes after rivals BHP Billiton and Vale switched to shorter term pricing arrangements. Sam Walsh, chief executive Iron Ore and Australia, said "Rio Tinto's position reflects the recent structural shift in the iron ore market away from benchmark pricing." "It is in line with our recent comments that benchmark pricing only works if it reflects market fundamentals, otherwise the system would need to change." As discussions are still underway, no further guidance is possible at this stage, the group added.