The Hancock Group of Companies are holders of numerous iron ore leases in the Pilbara. The leases cover an area of 500 square kilometres (190 sq mi) predominantly in the Central Pilbara region and contain mineable reserves of Brockman and Marra Mamba ore of over 850 million tonnes. Leases in the Eastern Pilbara region contain mineable reserves of Marra Mamba ore of over 2 billion tonnes, and over 500 million tonnes of ferruginous manganese in their Nicholas Downs Project which is a joint venture with mining services company Mineral Resources Limited. In 2011, the company was estimated to be earning about A$870 million in revenue per year. This is based on a 50% share of profits generated at the Hope Downs mine which is operated by Rio Tinto. Hope Downs production levels of 30 million tonnes per year and current prices (around US$140 per tonne) generate over A$2 billion in revenue, and about A$700 million in net cash. In addition, the company receives a 1.25% royalty from iron ore sales by Hamersley Iron (a Rio Tinto subsidiary) which delivers about A$170 million a year.