Coal: Natural Fuel from the Wetlands
The Kushiro Coalfield formed about 38 million years ago from the rich peatlands around Kushiro. Peat is created in wetlands and bogs when wet conditions and cold temperatures prevent dead plant matter from decomposing fully. These layers of partially decayed vegetation slowly accumulate as peat, and then gradually fossilize into coal as they are compressed under the weight of additional layers over the course of millennia. The Kushiro Wetlands contain Japan’s largest peatland, and the peat found there may one day form into coal.
The Kushiro Coalfield has more than 10 coal seams (layers of coal that are thick enough to be mined), each up to 5 meters thick. These seams, located east of the city of Kushiro, spread out under the seabed. Coal has been a major source of income and employment in Kushiro, contributing to the region’s development, since large-scale mining started here in 1920. At one time, the Pacific Coal Mine in Kushiro was one of the largest in Japan. Today, the Kushiro Coal Mine is the only underground mine still operating in Japan. It produces around 300,000 tons of coal a year.