BHP and Rio Tinto are heading in different directions

For years BHP and Rio Tinto, the world’s two most valuable miners, moved in lockstep. During the 2000s the twin Anglo-Australian giants rose on the back of China’s demand for commodities, particularly iron ore. In 2007 they even explored a merger (regulators rebuffed the idea). Then, when the commodity supercycle crashed in 2015, both landed...