580 GampunSampu[Rock Dusting]

The finest rock dust in the world was used in rock dusting.
Until the late Taisho era (1912-1926), Nittetsu Inatsuki Coal Pit also sprayed water (kirifuki) at abandoned long wall coalfaces as a countermeasure against coal dust explosions. But this measure required vast amounts of money for buying huge numbers of pipes and employing mechanics, and the work was very difficult.
In the beginning of the Showa era (1926-1989), they started rock dusting instead. At more than 200 meters underground, coalfaces were very dry and coal dust (tanjin) piled up thickly. Needless to say, far more coal dust was seen after using jack hammers (sakuganki). Meanwhile, coalfaces at upper seams in small pits had so much water that it made miners suffer from athlete’s foot and the skin disease bothered them very much. (The tunnels in small pits were cold but those in large pits were hot.)

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All underground coalfaces not saturated with water were called karashikis.

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Fummuki: sprinkler