FILE PHOTO: A sign adorns the building where mining company BHP Billiton has their office in Perth, Western Australia
JOHANNESBURG - BHP Billiton approved the $2.9billion (R38.58bn) development of its South Flank iron ore project in Western Australia to replace existing mines. 

The world's biggest mining company expects production to start in 2021 at the project, which is intended to replace depleting mines rather than adding new supply, BHP said yesterday. 

The development of South Flank will help BHP increase the quality of its iron ore at a time when high-grade material is selling at a premium. China's unprecedented steps to reduce pollution have increased the cost of iron ore as mills seek more efficient grades, which means they need less of the material to make the same amount of steel. 

- BLOOMBERG