In underground tunneling through soft or caving ground, miners drive these thick wooden or steel poles forward before excavating. The spills form a temporary roof or shield, protecting the crew while they muck out the loose material and install permanent sets. This technique is known as spiling or forepoling.
Drive a few more spills over that next cap before we try to pull any more dirt out of the face.
The term is often used interchangeably with spile, though some regions distinguish between the two based on thickness.
Also heard as
- spile
- forepole
Related terms
Timber drawer
A specialized miner tasked with safely removing wooden support props to allow the roof to collapse.
Timberman
A skilled underground worker responsible for cutting, fitting, and installing wooden structural supports.
Lath
A heavy plank driven ahead of a tunnel face to support loose ground during excavation.