What does square set timbering do?

Answer 1

If you've watched an old western you know what a classical mine looks like with it's posts and beams spaced regularly throughout the length of the mine tunnel. The posts and beams carried the load from the ceiling of the mine tunnel to the floor of the mine replacing the rock and ore that had been removed and, hopefully, kept the ceiling from collapsing.

Most minerals are contained in a shallow band so a tunnel six or seven feet high will excavate most of the mineral. Some mineral deposits, notably the Comstock Lode of Nevada, are an exception as the ore deposits may be in bands more than thirty feet deep. What to do?

Philip Deidesheimer, a German mining engineer, was hired in 1860 by the Ophir mine on the Comstock Lode to come up with a solution. He envisioned a honeycomb and designed a lattice work of cubes six feet square stacked upwards as ore was removed. The stacked square cubes allowed ceiling bracing to be carried upward to any height and the six foot cubes allowed a man to work the walls to remove the ore.