Economist: The coal industrys mood is smokestack-black. In China, which burns half the worlds coal, consumption in the first four months of 2015 was down by 8% year-on-year; imports by a stonking 38%. The market capitalisation of Americas four largest coal companies is $1.2 billion, down from $22 billion in 2010. America will shut 12.8GW of coal power-generating capacity in 2015, triple the 2014 figure. More will close next year. Natural gas and, increasingly, solar energy are cheaper and cleaner. The coal...