This ventilation shaft carries used, contaminated air out of the underground workings. Main extraction fans are typically mounted at the top of this shaft to pull air through the entire mine circuit, removing dust, exhaust fumes, and explosive gases.
Heard on the job
Gas levels are running a bit high at the upcast, so check the main fan speed.
Do not mix it up with
- Downcast: The downcast brings fresh air into the mine, while the upcast exhausts dirty air out.