Mine ventilation: Waste heat recovery

CIM Bulletin, Vol. 89, No. 998, 1996

L. Henry Smith, Williams Mine, Williams Operating Corporation, Marathon, Ontario David C. Arthur, V.B. Cook Co. Limited, Thunder Bay, Ontario

The Williams Mine is Canada’s largest gold producer, with annual production of 450 000 ounces from 2 300 000 tonnes of ore. Highly mechanized and automated underground mining practices are employed in order to achieve and maintain high levels of productivity and minimize costs. The mine ventilation system is modified to include a new vent raise and variable pitch vane-axial fan. This addition allows several fan installations underground to be decommissioned. A substantial net savings in installed horse power is achieved. Heating costs associated with underground ventilation air are a significant portion of mine operating costs. Air heating costs are substantially reduced by recovering heat from upcast exhaust air, mine water and compressor cooling circuits. This waste heat is used to supplement propane fired air heating systems for underground ventilation air. An additional benefit is the availability of a heat sink for summer cooling of the compressors. System design, energy savings data and payback calculations are presented.
Keywords: Underground mining, Ventilation, Heating costs, Energy savings, Heat exchangers, Variable frequency drives, Heat recovery, Propane burners, Vane-axial fans.