Rio Tinto has started producing iron ore from the Mesa A/Warramboo mine located 50km west of Pannawonica in the Pilbara region of Western Australia.

The $901m open-cut iron ore mine will have an initial production of 20 million tons per annum, increasing to 25 million tons by 2011.

Total high-grade reserves across the Mesa A/Warramboo deposits are estimated at 249 million tons, with a total mine life of 11 years.

The mine will sustain production of the sought-after Robe Valley pisolite ore at 32 million tons per annum as production from the Mesa J deposit decreases.