Coal prices are surging. China’s hunger for energy turned it into a net importer in 2009 of the thermal coal that fuels power stations, a trend that is set to continue. And steelmakers, fearful of the rising prices of raw materials, are hunting for captive sources of metallurgical (coking) coal as well as iron ore. Booming commodity prices are a burden as well as an immense boon for big miners. Rio, BHP Billiton, Vale and others are planning on vast increases in capital spending in the coming years, and have the bumper profits to finance it, yet there is only so much fruitful investment to be made in their current mines.