This robust wooden beam is installed across a mined-out void to support the surrounding rock or to serve as a base for a working platform. Miners often cover stulls with lagging boards to catch falling debris or to hold back waste rock used as backfill. They rely on the natural compression of the closing rock walls to lock them firmly in place.
We need to hitch a new stull across the upper stope before we start blasting the next slice.
A properly placed stull should be set slightly above the perpendicular line between the walls so that any downward settling of the hanging wall wedges it tighter.
Related terms
Stope
To excavate ore from an underground block by driving a series of steps or horizontal cuts.
Footwall
The block of rock that lies on the underside of an inclined fault or mineral vein.
Hanging wall
The block of rock that lies above an inclined fault plane or ore body.
Timberman
A skilled underground worker responsible for cutting, fitting, and installing wooden structural supports.