From the Australian Saturday 15/10 BHP Billiton, the world's biggest mining company, is considering a $US6 billion ($5.86bn) takeover of a US coal producer to support its view that supply of the sought-after commodity will be scarcer than iron ore in the next decade. http://www.theaustralian.com.au/business/mergers-acquisitions/bhp-set-to-bid-6bn-for-us-coal-giant-walter-energy/story-fn91vdzj-1226167127979Metro.