Sorry, not one case where that has happened. Please don't confuse the Eco-lies with naturally occurring shallow methane entering the water table. This natural occurrence has been happening long before there was a United States. Do an internet search for towns named "Burning Springs".
I took a look. Oil has been leaking into the gulf since time immemorial as well. Regardless, I think the risk to a few water wells is worth it. Worst comes to worst, haul in drinking water. And use the well water to heat your house.
Mining has inherent ecological risks and the risks that fracking pose pale when compared to those of say gold mining. No such thing as a free lunch.