A coal mine is a three-dimensional maze which changes its topography daily, expanding in one direction, as the men burrow deeper and deeper in pursuit of the coal, stopping short in another as the coal seam, displaced by some catastrophe in geological time, ends against a wall of rock, perhaps to be rediscovered many yards below or above the fault, perhaps to be given up as lost for ever. Within this maze roads are made and abandoned as the tide of battle moves on; others, no longer needed for the passage of coal, are kept open for the passage of air; others again, still needed for working purposes, may become blocked by falls of rock and be temporarily or permanently replaced by diversions. The older the colliery the more intricate and, to the outsider, the more bewildering its geography becomes.

Parts of the Dennis Section of Gresford Colliery were less up-to-date than others. In the districts known as 20s and 61s coal was still got by hand. A small group of miners went to their allotted ‘stall’, bringing the coal down and wheeling it away, leaving a substantial pillar of coal untouched to support the roof and moving on to open out a new stall. The other districts had been mechanised and were worked on the longwall system.