A 6 feet (1.8m) wide service tunnel, called a barrier, led from the underground roadway to each end of a 200 feet (60m) long coalface. These arrows shows the direction travelled by tools, pit props and other materials needed at the face. Pit ponies, pulling wagons along rails, transported these items to the end of the barrier. At the face, materials were loaded onto the face conveyer and carried along the face to where they were needed.
