Page 346 - Advanced Mine Ventilation

Measurement and Monitoring of Mine Gases 323

one of the three techniques capable of measuring hydrogen, nitrogen, ethylene, and
ethane. Determination of nitrogen is particularly important for determining oxygen
deficiency in some spontaneous combustion indicating ratios (refer to Chapter 21).
Similar to the tube bundle, problems exist with bringing the samples to the GC. The
significance of time delays in getting results is dependent on what the results are being
used for. GC is not going to be suitable for detection of a belt fire because of the time
delay between collection of the sample and analysis, but the delay is acceptable for
confirmation of other results or for evidence and trending of spontaneous combustion
indicators.
Like the tube bundle system, the gas matrix of the sample does not affect GC anal-
ysis. So long as appropriate calibration gases are available, this technique is capable of
measuring gases at any concentration above their detection limit. This eliminates the
problems seen with the other techniques, particularly for carbon monoxide concentra-
tions greater than 1000 ppm.
The ultrafast GCs in use in Australian mines allow the analysis of most of the com-
ponents expected underground in approximately 2 minutes.
This increased speed of analysis is invaluable during emergency situations, partic-
ularly when assessing the safety of the underground atmosphere for reentry or during
reentry by mine rescue teams. In these cases, what makes this assessment more effec-
tive is that GC is on-site and can be operated by mine personnel. There is no delay in
determining the status underground, while waiting for external providers to arrive or
transporting samples away from site for laboratory analysis.

References

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[3] Holaday DA. Control of radon and daughters in uranium mines and calculations of biologic
effects. Washington, DC: Publication No. 494, U.S. Department of Health, Education and
Welfare; 1957.
[4] Thakur PC. In: Darling P, editor. Gas and dust control in SME mining engineers handbook;
2011. p. 1595e609.
[5] Rowland JH, Harteis SP, Yuan L. A survey of atmospheric monitoring systems in US
underground coal mines. Mining Engineering 2018;70(No. 2):37e40.
[6] Morton J. New wireless tech for underground mines could save lives, costs. Coal Age April
2018:20e3.
[7] Brady D. The role of gas monitoring in the prevention and treatment of mine fires, Coal
Operator’s Conference, the AusIMM. February 2008. p. 202e8.