FEATURE
Ventilation and Cooling in Underground Mines
Underground mine ventilation is particularly important in situations where heavy machinery is in operation , as plants such as drills and long haul dumps have a huge impact on humidity and temperature . On top of this , extraction can release gases which are harmful to staff working below ground . For example , radon , which is often present in uranium mines , is poisonous if inhaled .
The main objective of mine ventilation is the provision of sufficient quantities of air to all the working places and travel ways in an underground mine to dilute to an acceptable level those contaminants which cannot be controlled by any other means . Where depth and rock temperatures are such that air temperatures are excessive , mechanical refrigeration systems may be used to supplement the beneficial effects of ventilation .
The Mine Atmosphere The composition of the gaseous envelope encircling the earth varies by less than 0.01 % from place to place and the constitution of “ dry ” air is usually taken as 78.09 % nitrogen , 20.95 % oxygen , 0.93 % argon and 0.03 % carbon dioxide . Water vapour is also present in varying amounts depending on the air temperature and pressure and the availability of free water surfaces . As ventilation air flows through a mine , the concentration of water vapour may change significantly and this variation is the subject of the separate study of psychrometry . To define the state of a water vapour and dry air mixture at a particular point requires the three measurable independent properties of barometric pressure , dry bulb and wet bulb temperatures .
Ventilation Requirements
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