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Gas and Dust Explosions 395
Table 23.8 Minimum Incombustibles in Coal Mine Dust
Minimum Incombustible Minimum Ratio
(S) Required in the Dust Incombustible to
S
Country Year Mixture, pct Coal
100LS
Belgium 1965 60e78 1.5e3.5
Canada 1959 65 1.9
Czechoslovakia 1957 80 4.0
Germany 1965 80 4.0
Poland 1959 70e80 2.3e4.0
South Africa 1959 50 1.0
United Kingdom 1961 50e75 1.0e3.0
USA (Federal) 2014 80 4.0
USSR 1953 60e75 1.5e3.0
Methane %
Methane %
Figure 23.9 Minimum explosive concentrations of a mixture of coal dust and methane gas.
