Room and Pillar Long Wall Strip Mining Surface Mining

In pillar and stall workings, miners first created a passageway straight into the heart of the coal seam. Once the seam was accessed, miners created rooms by removing coal from a sizeable underground area, but were careful to leave large tracks of coal behind. The untouched coal would act as pillars that supported the roof of the mine and prevented cave-ins as the miners cut deeper into the seam.

Through this method, miners created a honeycomb of rooms and pillars that were occasionally bisected by long haulage tunnels. The extent of these tunnels depended on the furthest reaches of seam, and were often several kilometres long. Once miners removed coal from the farthest extent they could reach, they would then backtrack. Since pillar coal was easily accessible, miners would then rob the coal from the pillars. Workers took extensive care when removing this coal since pillar subtraction weakened the roof structure and room would eventually cave in.

To prevent cave-in accidents, tunnels also required timbers as pit props, which supported the rocks and prevented smaller debris from falling onto the miners.