A colliery is a coal MINE, which is composed of a MINE shaft and a PIT. The term colliery is derived from the Latin word for coal, 'collis'. A colliery typically consists of a series of underground tunnels and chambers that are used to extract coal from the earth. The MINE shaft is the vertical tunnel that is used to access the coal deposits, while the PIT is the horizontal tunnel that is used to transport the coal to the surface.