This illustration, a section cut through a stope, shows how square-set timbers in a Butte mine supported the hanging wall of a stope after the ore had been mined. Miners built a floor atop the square sets so they could drill upward into the remaining ore above. The figure also shows how waste rock was backfilled into square sets to help support the hanging wall. Timbering a mine used prodigious amounts of wood, as one can imagine when realizing that stopes extended for hundreds of feet. | Source: Harrer, “Square-Setting in the Butte District,” Engineering & Mining Journal 124 (30 July 1927): 169. Download Original File
Source
Harrer, “Square-Setting in the Butte District,” Engineering & Mining Journal 124 (30 July 1927): 169.
