The process known as mountaintop-removal coal mining has come under fire from environmental groups who deplore its effects on communities in Appalachia. The method combines clear-cutting of mountain forests with the use of explosives to shake loose the rock that covers coal deposits. Its critics say the mining’s economic benefits are far outweighed by the destruction of ecosystems in West Virginia, Kentucky, Virginia and Tennessee — whose recent flooding, opponents say, was exacerbated by the process. And that’s not to mention how coal use can accelerate climate change, or the aesthetics of storing coal slurry in lagoons throughout the region. Tonight’s show benefits the Natural Resources Defense Council, a not-for-profit environmental organization. Performers slated to appear include jam-band icon Dave Matthews and country singer Emmylou Harris, along with Alison Krauss, Big Kenny and Buddy Miller. Also on the bill is Kathy Mattea, a West Virginian whose 2008 record Coal remains a devastating piece of political art.