Pannawonica is one of two mines in Robe River JV and is operated by majority owner Rio Tinto. It has annual production of 34 million tonnes. Due to the simplistic nature of mining pisolite ore, Pannawonica is one of Rio Tinto's lowest cost mines. The mine also has the lowest strip ratio of any Rio Tinto mine at 0.4:1, assisting in keeping costs low. It produces a low-Fe grade product that is also low in phosphorus.