Mining Publication: Technology News 499 - Using Propeller Fans to Improve Ventilation in Large-Entry Stone Mines

Research on propeller fans in underground drift stone mines has shown that significant ventilation improvements can be achieved. In large-entry mines that do not have any high resistance-sections (shafts> 100 ft long or shaft diameters <12 ft, propeller fans can greatly increase the total system airflow. Propeller fans can be used as either main mine fans or as freestanding auxiliary (jet) fans. NIOSH researchers have documented the performance of two recently installed propeller fans in a working limestone mine. Together the fans exhausted 750,000 cfm at a rated hp of 200. The use of the propeller fans more than doubled the air quantity while operating at 50 hp less than the original main mine fan system. In addition, the new fans, when used with effective air-coursing methods such as stoppings, reduced or eliminated recirculation near the face areas. This is because propeller fans are more efficient at lower pressures and can produce large air quantities at lower horsepower requirements than axial vane fans.