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314 Advanced Mine Ventilation
Table 19.1 Gas Detection Methods
Gas Detection Methods
Methane Flame safety lamp
Catalytic oxidation
Thermal conductivity
Optical (infrared and interferometer)
Oxygen Liquid absorption
Stain tubes
Paramagnetic analyzers
Electrochemical sensors
Carbon dioxide Liquid absorption
Stain tubes
Optical interferometer
Carbon monoxide Electrochemical sensors
Catalytic oxidation
Optical and infrared
Metal oxide semiconductor
Stain tubes
Oxides of nitrogen Electrochemical sensors
Stain tubes
Hydrogen sulfide Electrochemical sensors
Metal oxide semiconductors
Stain tubes
Sulfur dioxide Electrochemical sensors
Stain tubes
Hydrogen Stain tubes
Radon Radiation detectors
Detection (more correctly spot readings) methods for different gases are listed in
Table 19.1 [1].
Many instruments have been developed over the past 100 years to measure the
instantaneous concentrations of all important gases listed in Table 19.1. The oldest
is the flame safety lampda symbol of safety in mines. It detected both the lack of ox-
ygen (above 13%) and small concentrations of methane (below 5%) and provided light
as well for miners to work safely. It is almost obsolete by now. Instruments specially
suited to measure the concentration of important gases are discussed below.
19.1.1 Methane Measurement
Two handheld instruments are most commonly used. The first one, which is cheaper,
uses the catalytic-oxidation technique. It works on the Wheatstone bridge principle:
