Used in
longwall mining, a chain pillar is a pillar of
coal left intact in the mine to protect the
gangway and parallel airways. Chain pillars can be square, rectangular or diamond shape, in single or double or double row configuration.
Check curtains are hung across the airways among the chain pillars to control the passage of
air current.
The types of pillars include:
- Barrier pillars - between the mining panels and underground reservoirs
- Entry pillars - that protect the mines entries
- Panel pillars - formed during the development of mining panels
- Split pillars - formed by splitting panel pillars prior to depillaring
- Remnant pillars - the diminising remnants of split pillars during the depillaring proces