coalfield

noun

1. Any region containing deposits of coal that may be mined.

   “The east-west flow consists in the westerly direction of the agricultural and industrial products of East Anglia; imports through London and Parkeston (Harwich); special traffic in coke to the Northamptonshire ironfield; and mineral empties returning to the Derbyshire, Nottinghamshire, and South Yorkshire coalfields.”

   “The amount of coal despatched in the Western Region is about 24,000,000 tons a year, nearly all from South Wales, though the Region includes the Forest of Dean, N. Somerset, and part of the N. Wales coalfields.”