Two multinational companies - Trafigura from Singapore and Ivanhoe Mines from Canada - have signed a major deal to export copper along a railway from the Democratic Republic of Congo.

The corridor to the Angolan port of Lobito has been part-funded by the United States to try to compete with China for access to minerals.

The colonial-era railway reopened in 2015 after closing during Angola's civil war but traffic has struggled to take off.

Global demand for copper is growing as it is vital for the manufacture of solar panels and electronics.