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
A: More coal loss
B: Fire prone
C: Big coal dust
D: Gas is easy to accumulate
举一反三
- 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
- When the middle inclined cutting is adopted, the coal cutting mode of the fully mechanized working face is .
- 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
- Quantity of energy contained in the atmosphere is ______. A: smaller than that in coal alone B: smaller than that either in oil or in gas that we have on Earth C: greater than that in coal, oil and gas on Earth combined D: greater than that in coal, oil and gas on Earth, respectively
- What are the main selection of equipment in the fully mechanized working face? ( ) A: Selection of fully mechanized support B: Selection of Shearer C: Selection of face conveyor D: Selection of conveyor in gateway