Quantity and power
Airflow quantity is air velocity times the cross section of the airway, Q = V x A, in cubic meters per second. The power delivered to the air is that flow times the pressure the fan develops. Dividing by fan efficiency, taken here as 70 percent, gives the electrical power the motor draws.
In a real mine, pressure and flow are linked: airway resistance makes pressure rise roughly with the square of flow. This model lets you set them separately to keep the arithmetic visible.
Try it: set the velocity to 6 m/s, the area to 40 m² and the pressure to 4000 Pa. The fan power climbs past 1,300 kW, which is why ventilation is often one of the biggest power users in an underground mine.
Exhausting versus forcing
Most large mines use exhausting fans like this one, which keep the whole mine slightly below atmospheric pressure. If the fan stops, gas tends to stay in the workings, so fan monitoring and backup plans are a core safety duty.