The purpose of an auxiliary fan is to provide local ventilation in areas that the main mine or industrial ventilation system cannot reach directly. In underground mining and in complex industrial plants, the primary fans move air through main intakes and returns, but this airflow does not automatically reach every blind heading, development drive, stope or enclosed room. Auxiliary fans, working together with ventilation ducts, extend the reach of the main system so that workers and equipment always receive enough fresh air.
In an underground mine, an auxiliary fan is typically installed at the entrance to a development heading or branch and connected to a line of flexible or steel ducting. In a forcing system, the auxiliary fan blows fresh air down the duct towards the face, pushing clean air into the work zone and sweeping fumes, dust and heat back into the return airway. In an exhaust system, the fan pulls contaminated air from the face through the duct and discharges it into a return, allowing fresh air from the intake to flow naturally toward the face.
Auxiliary fans play a key role in controlling gases, dust and temperature in small or advancing workplaces. After blasting, diesel equipment operation or welding, concentrations of gases and dust can rise quickly in a confined heading. A correctly sized auxiliary fan and duct system restores safe conditions more quickly, reducing re-entry delays and improving productivity while keeping the workplace within regulatory limits for gas, dust and heat.
In industrial settings such as large workshops, process plants or tunnels under construction, auxiliary fans are used in a similar way. They provide spot cooling and fume extraction around hot equipment, confined spaces, welding areas or temporary enclosures. By directing airflow exactly where it is needed, they complement the main HVAC or ventilation system without requiring major modifications to permanent ductwork.
Another purpose of auxiliary fans is to give operators flexibility as layouts change. Development headings and temporary work areas move frequently, especially in mining. Flexible ducts and portable auxiliary fans can be relocated as the face advances, maintaining effective ventilation with relatively low cost and short set-up times.
In summary, the purpose of an auxiliary fan is to extend the main ventilation system into blind or remote areas, delivering fresh air and removing contaminated air at the workplace. It is a critical tool for maintaining safe, comfortable and productive conditions in underground mining and industrial environments.
