Not surprised. When the competing (and better performing, environmentally and for convenience, at least for natural gas) fuels are striving mightily for zero cost, coal at any price becomes less competitive. At which point the economically extractable reserves shrink. It's not so much that there's less coal in the ground; but there's less coal that it makes sense to go after. If that and the switch to n.g. happen to improve the air pollution and GHG picture somewhat, I won't complain.