A: The requirement for through-ventilation
B: The corrosion some types of coal will cause to the ship
C: Spontaneous heating
D: Generation of methane ga
举一反三
- When conventional heating cannot be avoided, the energy carrier will define carbon emissions. What is the order of coal, oil, and natural gas? A: oil < gas
- The English “first-footer” should be carrying coal, money, or bread, symbolizing _____.
- The most easily oxidized coal is (). A: lignite coal B: bituminous coal C: lean coal D: anthracite coal
- Users of heating oil were unaffected by the coal ______. A: decline B: vacancy C: rarity D: shortage
- During top coal caving mining, the essential cause of top coal crushing is ( ). A: softening of water in roof strata B: the stress it beared is large than its own strength C: the gas in the top coal expands, leading to breakage D: cracks produced by raw coal during its formation
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What are the main disadvantages of fully mechanized caving technology? ( ) A: More coal loss B: Fire prone C: Big coal dust D: Gas is easy to accumulate
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Which of the following is not a common way for coal caving? ( ) A: Top caving coal in group sequence B: Top caving coal in single cycle sequence C: Top caving coal in multiple cycles in sequence D: Top caving coal in intervals of single cycle
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中国大学MOOC: In England, a dark haired person is asked to enter through the front door at midnight with salt, coal, and bread in his possession. And they believe coal suggests __________ in the new year.
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Rail transport uses different types of wagons for different goods, usually are used for move coal and aggregates.
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The dry ash free volatile content of a coal is 7%, which is most likely to belong to (). A: Bituminous coal B: Anthracite C: Lignite D: Lean coal