Coal Pits (Yama) in the Old Days: Collapse, Repair, and Open Cribbing
April 1965

Mukashi no Yama: Takabare, Shikuri, Karakozumi
[Coal Pits (Yama) in the Old Days: Collapse, Repair, and Open Cribbing]
38.0 x 54.0 cm Painting in Watercolors and Ink

Even hard points of old slope roofs sometimes collapsed heavily (takabare) from rock pressure. In this case, the collapsed ceiling would be raised by a few meters. If the roofs of important slopes collapsed, cribbing called kara-kozumi (open cribbing) was built on frames to support the new ceiling. Mine timber was piled in tiers and arranged in parallel crosses. Building kara-kozumi on frames required much timber and great skill. It was so dangerous to build that no women atoyamas (helpers) were used.
Repairers repaired roofs of secondary levels, which were only narrowly collapsed, by driving skin to skin lagging (jigokunari) instead of supporting them with complete kara-kozumi. In this case, they arranged mine timber in two tiers of parallel crosses on the frames, laying some pieces of thin lagging with ends about 80 millimeters in diameter on the cribbing so that they could more easily repair the points later. Additionally, they put coarse debris on top of the lagging to prevent it from moving.

Word in the Inset
tenjo: roof; ceiling


Translation Assisted by Mr. Nathan Johndro

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