Coal is a mineral used to power electricity and/or heat.
It is a black rock.
Scooby-Doo, Where Are You!
Fred Jones, Velma Dinkley and Daphne Blake slid down a coal chute and landed in a coal pile when they were trying to escape the Witch.
The basement of Col. Beauregard Sanders's mansion is full of it, as Scooby-Doo found out after falling down a ramp, which lead from a trap door in the wall of his bathroom.
The New Scooby-Doo Movies
The mine ride at the 3 Stooges Ghost Town has real coal in the mine carts.