coalfield; coal field
Refers to a region where coal is mined. Common in geographical and industrial contexts.
There is a large coalfield in this region.
There is a large coalfield in Hokkaido.
Development of the coalfield is progressing.
A coalfield was discovered in this area in the 19th century.
The government drew up a plan to develop this coalfield.
油田 and 炭田 share the same '〜田' pattern for resource-rich areas, but 油田 is an oil field while 炭田 is specifically a coalfield.
submarine coal field
Compound of 炭 (coal) and 田 (field), referring to a coal-bearing area.