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 slurry came out of the mine openings, sending an estimated 306,000,000 gal of slurry down two tributaries of the Tug Fork River.
Relevant evidence: Yes