Page 23 - Advanced Mine Ventilation

6 Advanced Mine Ventilation

Figure 1.1 A typical underground coal mine layout.

1.3 Properties of Air

Because large quantities of air, sometimes 20 tons of air for each ton of coal mined, is
circulated through the mine airways, it is important to know its properties. The chem-
ical composition of air is as follows:

Component Gas Percent (Volume) Percent (Weight)
Nitrogen 78.09 75.55
Oxygen 20.95 23.13
Carbon dioxide 0.03 0.05
Other gases (argon, water vapor, etc) 0.93 1.27

Air is a physical mixture of these gases with a specific gravity of 1.00. It is a color-
less, odorless, and tasteless gas that supports life and combustion via its oxygen con-
tent. Some important properties of air are listed in Table 1.4.