This video shows a Grandfather changing the water filter on his well water in Prenter, WV. Coal Waste has been injected into abandoned underground mines near his house. See sludgesafety.org for more info on coal slurry.
Hydrofracking involves storing gas underground and disposing of fracking sludge in abandoned mines, both a potential threat to groundwater.
See Aurora Lights article on Coal Mining's effect on clean water in West Virginia.