While mine ventilation systems may account for 40% to 50% of the energy consumption of a mine operation, auxiliary ventilation alone may be accountable for half of this consumption. In effect, auxiliary ventilation systems comprise a significant portion of a mine operation's base energy demand and is consequently responsible for a large percentage of the total mine operating costs.
While modern duct-fan systems require precise engineering design, meticulous attention to installation and regular maintenance practices, many installations are often designed based on outdated rules of thumb and with disregard to best installation practices.
Over twelve years of investigations of duct-fan systems, the author has found them to be, in general, fairly energy inefficient, with many systems operating at efficiencies below 65% and with air leakages ranging between 25% and 75%.
This paper presents how engineering design principles can be applied to design efficient and reliable auxiliary ventilation systems, especially focusing on assemblage losses. Case studies are presented to demonstrate the effect of design, installation and maintenance practices on system reliability and operating costs. In particular, the effect of assemblage losses (screen, inlet bell, elbows, couplings, duct outlet, etc.) is quantified in terms of operating efficiencies, energy consumption and costs.
