【Daily Topic】【Engineering Version 20160507】
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Participation reward: 2 Wealth. Reward for the correct answer: 9 Wealth. Coal mine permits are classified into 5 grades based on their gas safety levels; the coal mine permit that is most suitable for mines with high gas concentrations and coal dust explosions is ( ). A. Approved for Grade 1 coal mines ** B. Approved for Grade 2 coal mines ** C. Approved for Grade 3 coal mines ** D. Approved for Grade 5 coal mines**
C. Permitted for Class 3 coal mines**
A. Permitted for Class 1 coal mines**
B. Permitted for Class 2 coal mines**
Coal mine permits are classified into 5 grades based on their gas safety characteristics; the permit type most suitable for mines with high gas levels and coal dust outbursts is (C). A. Approved for Grade 1 coal mines ** B. Approved for Grade 2 coal mines ** C. Approved for Grade 3 coal mines ** D. Approved for Grade 5 coal mines**
C. Permitted for Class 3 coal mines**