Question: Which Central Appalachian coal producer was responsible for a spill that dumped 306 million gallons of slurry into tributaries of the Tug Fork River? 
Sentence (from "Martin County coal slurry spill"): The Martin County coal slurry spill was an accident that occurred after midnight on October 11, 2000 when the bottom of a coal slurry impoundment owned by Massey Energy in Martin County, Kentucky broke into an abandoned underground mine below.
Relevant evidence: Yes