Translation guide
A layer or deposit of coal in the ground. In Japanese, this is typically expressed with compound words using 炭 (tan, 'coal') and 層 (sō, 'layer') or 床 (shō, 'bed').
Referring to a stratum or seam of coal in the earth.
The standard geological term for a coal seam or coal bed.
この地域には厚い炭層がある。
There is a thick coal bed in this region.
Explicitly says 'coal layer', often used in mining and geology.
石炭層の採掘が始まった。
Mining of the coal bed has begun.
A less common term, literally 'coal bed', used in some technical contexts.
炭床の厚さは約2メートルだ。
The thickness of the coal bed is about 2 meters.