MINE VENTILATION - WASTE HEAT-RECOVERY

The Williams Mine is Canada's largest gold producer, with annual produ ction of 450 000 ounces from 2 300 000 tonnes of ore. Highly mechanize d and automated underground mining practices are employed ii, order to achieve and maintain high levels of productivity and minimize costs. The mine ventilation system is modified to include a new vent raise an d variable pitch vane-axial fan. This addition allows several fan inst allations underground to be decommissioned. A substantial net savings in installed horse power is achieved Heating costs associated with und erground ventilation air are a significant portion of mine operating c osts. Air healing costs are substantially reduced by recovering heal f rom upcast exhaust air, mine water and compressor cooling circuits. Th is waste heat is used to supplement propane fired air healing systems for underground ventilation air. An additional benefit is the availabi lity of a heat sink for summer cooling of the compressors. System desi gn, energy savings data and payback calculations are presented.