There is no need to ventilate the entire mine because production may only be concentrated in, say, 20% of the facility at any one time.
Although the concept of ventilation in underground mines may seem relatively simple, getting the right quantity and quality of air to where it's needed, when it’s needed, in an expanding mining environment is an elaborate operation that requires an array of ventilation components.
Typical ventilation systems consist of the main fan system, air regulators and doors that distribute air through the mine. There are also auxiliary systems that ventilate local production areas and workshops. Air requirements in an area depend on its location, the number of people there and which machines are being used.