Ventilation is the flowing of air through the workings of a mine to provide personnel with a supply of clean healthy air. It should be able to circulate in sufficient quantities to sweep away dust and gasses in the mine. It is the first defence against the accumulations of gas and explosions. To help ensure adequate air circulation ventilation fans were installed.
Depending on the direction of the natural breeze, a fan could be either an intake or exhaust.
This orange ventilation fan is 100 horsepower and runs at 330 rpm (rotations per minute). The Bellevue Mine had four large ventilation fans available for use, but for the most part only two were used to save power.