（解説文要約）
明治の中ごろ、筑豊地方の小規模炭坑には低炭層、つまり、石炭の層が薄い採炭現場が多くありました。

低炭層のヤマは、主要坑道も天井が低く、

炭車に石炭を山のように積み込むと、天井につかえて進めなくなることもありました。

当時、山盛りに石炭を詰め込んだ状態が規定量だったので、摺り切りいっぱいでは賃金が2割カット。

天井が低いヤマに炭鉱労働者たちは泣かされていました。

 

 

 

 

Around 1900, there were many coal faces in thin seams at small sized coal mines in the Chikuhoregion.

In these mines, the ceilings of the main drives as well as the coal seams were low.
Therefore, when coal skips were loaded with too much coal, they got stuck.
Miners’ wages were determined according to the amount of coal in a skip. 
This amount was regulated: one heaping load of coal per skip.
If miners were unable to produce one heaping amount of coal, and only a flat, level amount of coal, their wageswere cut by 20 percent.
Miners working at these low ceilinged mines were out of luck when it came to fair wages.