ABSTRACT
The depletion of near surface reserves in most mines has led to mining at great depths and at great distances from main shafts. As a result the air streams from the main ventilation systems reaching these working places are often insufficient, ineffective or inadequate (Wilson & Eben 1982) and have to be supplemented by auxiliary ventilation systems to maintain the gas concentrations within safe limits and create congenial working environments there. Increasing concerns for human comfort and safety, have led to the promulgation of more stringent environmental laws which have raised environmental standards in most mines substantially (Hartman 1973). However, due to the increased depths of mining, size and complexity of most mines, there are high demands on the ventilation system to maintain more stringent standards on environmental quality required by the laws. In development headings in underground coal mines, emissions of methane gas from the strata, dust from the coal cutting operations at the face, heat from the strata and face machinery as well as from the conveyed material generally combine to create unhealthy environments in the headings (Rabia, 1988).
