The Lancashire Coalfield was one of the most prolific in England. The number of shafts sunk to gain coal number several thousand, for example, in 1958, Wigan undertook a survey of old shafts and located 500. In 1995 following several years of redevelopment across the Wigan Metropolitan Borough by the British Geological Survey (BGS), in association with the planning consultants Roger Tym & Partners, the list had grown to over 1000 with no real idea of the total. Similar surveys in Bolton and Manchester have also produced long lists of undocumented shafts.