Is underground coal gasification a sensible option?

Is underground coal gasification a sensible option?
from It is 6 Minutes to Midnight | Bulletin of the Atomic Scientists by Kurt Zenz House

There's a lot of coal in the ground. In 2006, the U.S. Energy Information Agency estimated that global coal reserves (i.e., the total quantity of coal that can be economically produced) stood at roughly 840 gigatonnes. That's enough to supply the world for more than 130 years.