trap

In coal and metal mines, a trap was a hinged or sliding door fitted into a passage or shaft to control the flow of air currents used for ventilation. The person who worked it, the trapboy or trapdoor keeper, would open and close it in sequence as miners and laden trucks passed through, preventing air from short-circuiting around the working seams. The trap ensured that forced or natural draft moved through the active workings where gas needed to be cleared and fresh air delivered.

Most traps were simple wooden frames hung on pivot hinges or mounted to slide in wooden grooves. A boy or young man would sit beside it for hours or an entire shift, pulling a rope or pushing against the frame to open it as traffic came, then releasing it to swing shut behind. Some mines used counterweights or springs to reduce the physical effort needed. The location of a trap was critical: it had to be placed where air currents would be most effectively directed into the coal face or away from areas where firedamp or other noxious gases accumulated.

The work was numbing and dangerous. Trapboys were often children aged 8 to 14, stationed in cold, damp, dark passages for 12 hours or more. Falling asleep at the trap could allow explosive gas to accumulate in working areas. A careless or inattentive trapboy could also be struck by runaway trucks or caught by the trap door itself if it swung unexpectedly on its hinges.

As mechanical ventilation systems became standard in the late 19th and early 20th centuries, the need for hand-operated traps diminished. Motorized fans and ductwork replaced the manual control of air by hinged doors. The role of trapboy had largely disappeared from developed mining operations by the 1950s, though the term persisted in some older mines and in historical mining records long after the practice itself ceased.