As soon as the machine is well under way, the runner determines about where the next rear jack-hole will come, and has the cut made and ready for receiving the jack by the time the machine has finished its cut.1907, Rock Boring, Rock Drilling, Explosives and Blasting, Coal-Cutting Machinery, Timbering, Timber trees, Trackwork, page 48:
Trout glided into the shadows, feeding upon grey moths, while in the jackhole beneath the red clay hollows big pike stirred lazily.1911, The Nation - Volume 9, page 906:
3 more examples
It was therefore decided to drive one jackhole through to the surface, and after passing through the inferior coal, the alluvium was met with, and found to be so light and loose in character that it ran through at this point to the surface. The jackhole had therefore to be abandoned, and no further attempts were made to pierce the strata.1913, Institution of Mining Engineers (Great Britain), The Mining Engineer, page 379:
The particular work he was doing when the accident occurred was digging with pick and shovel a jackhole under one of the track rails to prepare a foundation for a track-lifting implement.1927, Reports of cases determined in the district courts - Volume 74, page 22:
Finally, Spindrick came to a jackhole with the cover off and protected by a circular barrier.2011, Garry Kilworth, Gaslight Geezers:
jackhole
noun
Etymology Blend of jackass + asshole; possibly originated as a euphemism.