3.2.4 Wall Support

As the drifts extended further away from the shaft and became an increasingly permanent route for both ore and people, the walls and ceilings had to be secured. This need was recognized as far back as the 18^th century.

		Method of bracing mine drifts. Diderot, circa 1750.
	Source

In the early days, timbers were widely used as supports, as shown in the illustration, to retain the blocks of rock that could come loose during explosions or to reduce the subsidence caused by the weakening of geological structures due to the infiltration of water. The bracing had to be designed in such a way as to allow people and transport vehicles to circulate by rail.

		Timber bracing of drifts walls, Abitibi region 1930-1940.
	Source

Substantial quantities of timbers were sometimes required and the ready supply of wood around the mines in the Northwest made it the material of choice.