One of the most hazardous vocations on record, early coal mining was nothing more than men with picks undercutting hundreds of feet of rock to extract a narrow seam of coal. The room-and-pillar system for removing coal was highly productive, but very dangerous. Some coal was left in place to support the rock layers, and thousands of wood timbers were used to brace the rock above the voids so that the coal could be loaded. Dislodging the coal involved a miner bringing his own keg of black powder into the mine, which when packed into drilled holes could detonate prematurely or not at all. Miners worked separate rooms sometimes miles from the main shaft, which meant little supervision. Add to this the pay-per-ton wages wherein a miner often overlooked his own safety so that as much coal as possible could be loaded.
What could possibly go wrong?