9th International Symposium on Mine Planning and Equipment Selection, Athens, Greece, 6 - 09 November 2000, pp.105-109
The design of auxiliary ventilation systems for long drivages and tunnels requires the installation of multiple fans acid it has vital importance. If the fans are installed next to each other air leakage in duct is high. Therefore, the fans are installed in series and separated from each other by rigid ducts of fixed or variable length. For a constant length duct design problem may be approached in two ways.