The low-energy-value discards of the coal mining industry. Waste coal is called “culm” in the eastern Pennsylvania anthracite coal region and “gob” or “boney” in the bitiminous coal mining regions (western Pennsylvania, West Virginia and elsewhere). Waste coal piles accumulated mostly between 1900 and 1970. The piles look like hills or small mountains that are dark and barren. Hundreds of millions of tons of waste coal and rock litter the landscape in mining states. Waste coal piles leach iron, manganese and aluminum pollution into waterways and cause acid drainage that kills neighboring streams. These piles sometimes even catch fire, releasing toxic pollution into the air.