Chemical elements
    Physical Properties
    Chemical Properties
      Oxygen in Air
      Carbon Dioxide
      Desiccation of Air
      Atmospheric Ozone
      Atmospheric Nitrogen
      Hydrogen in the air
      CO in Atmosphere
      Miscellaneous Substances
      Soil Atmosphere
      Mine Air
      Tunnel Air
      Bacteriology of Air
      Respired Air
      Air Mixture
      Physical Properties
      Liquid air
    Hydrogen peroxide

Mine Air

The Mine Air, or air in mines has been made the subject of considerable investigation. Freshly hewn coal evolves methane and other gases, and absorbs or occludes gases from the air, oxygen being taken up rather more rapidly than nitrogen. This is well exemplified by the following table which gives the relative proportions of oxygen, nitrogen,

Freshly hewn Coal.Coal exposed to Air.
Carbon dioxide1.61.18

carbon dioxide, and methane contained in samples of freshly hewn coal, and in other samples of the same coal after prolonged exposure to air.

It is not surprising, therefore, that the air of mines should exhibit a deficiency in oxygen and an increase in the percentage of carbon compounds. Analyses of air taken at different levels in a Scottish mine, are given by Whalley as follows:

Oxygen.Nitrogen.Carbon Dioxide.
Near the floor13.1382.284.56
Near the roof20.0879.20.69
Near the coal face18.9779.81.21

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