Why does BHP want Anglo American?

From The Economist

This clash of big dirt and high finance suggests that Anglo harbours something worth fighting over. Its big mines indeed tick all the right boxes: high quality and low cost, with the potential to expand. They are also extracting the right stuff at the right time. One of Anglo’s main products is copper, which is in high demand, particularly as tonnes of it will be needed for the electrification of transport and power in the green-energy transition; the red metal’s price has risen by 15% this year. Another is high-grade iron ore, which is in demand for its use in forging green steel.