In addition to being an important partner in the venture, Vale is responsible for supplying the iron ore to be used by the steel mill complex, through a 15-year contract signed with ThyssenKrupp.

The South Korean mill earlier this year agreed to buy as much as 15 percent of the Roy Hill iron ore project in Australia and a 7.8 percent stake in a coal mine in Mozambique.

The crushed ore leaving the mill was allowed to flow over an inclined copper plate covered with a thin layer of mercury.