A vertical or steeply inclined underground passage through which blasted ore or waste rock is dropped by gravity to a lower haulage level. At the bottom, the material is typically drawn off through a chute into mine cars or trucks. The term is also widely used for the surface facility where ore is crushed and processed.
Heard on the job
Dump that muck down the number three mill and we'll draw it from the 400 level.
Also heard as
- ore pass
- rock pass
Do not mix it up with
- Concentrator: A concentrator is the surface processing plant, which is also commonly called a mill, whereas underground miners use mill to mean an ore pass.
Related terms
Glory hole
A large, open excavation used to funnel blasted ore into underground workings, or a seafloor pit protecting oil equipment.
Stope
To excavate ore from an underground block by driving a series of steps or horizontal cuts.
Winze
An internal mine shaft excavated downward from one underground level to a lower one.