definition
strict definition
coal mine
A site where coal is systematically extracted from the earth through tunnels, open excavation, or blasting.
A coal mine is a place where coal is removed from the earth for eventual use. It can be a system of tunnels, an open excavation, or blasted area where coal is systematically extracted.
The workings can be underground or exposed at the surface. Tunnels are therefore one possible form rather than a requirement for a coal mine.
Coal must be extracted at the site. Storage, transport, or use of coal brought from elsewhere does not by itself establish the mining use.