Coal will not be able to replace the other fossil fuels. Whether extraction peaks in 2011 or in 2050, the probabilities of coal on its own being able to help the world avoid the Olduvai cliff are slim at best.
Certainly, this fossil fuel can still become more relevant as a fuel in some regions of the world.
This can occur in the US for instance, if reported reserves are anywhere near a geological reality. In such places, coal can provide time for a smoother transition to a fully renewable energy paradigm, but on a global scale, the panorama is entirely different.
For states or nations that are net importers today but do not possess realistic reserve perspectives, the use of coal is more a thing of the past than of the future.