Q1)
Main fall occurs When the area of extraction is nearly equal or more than the .....of the depth?
1) twice
2) thrice
3) square
4) cube
Q2)
Upto what gradient the Bord and pillar mining can be adopted withour special arrangements?
1) 1 in 3
2) 1 in 4
3) 1 in 5
4) 1 in 6
Q3)
If the pillars are not strong they may be crushed due to sudden pressure is called?
1) premature collapse
2) normal collapse
3) local fall
4) overriding of pillars
Q4)
In which line of extraction one solid stook intervenes between two stooks under extraction at a time?
1) Diagonal
2) Step diagonal
3) parallel to strike
4) Arrow head
Q5)
In which line of extraction the pillar or stook is under excessive pressure and is liable to crush?
1) Diagonal
2) Step diagonal
3) parallel to strike
4) Arrow head
Q6)
If the depillaring is proceeding from dip to rise and seam inclination is not mild so that goaf can be submerged in water then the line of goaf is?
1) Diagonal
2) Step diagonal
3) parallel to strike
4) Arrow head
Q7)
In shallow seams to prevent breathing of air to the depillared area through cracks to the surface the cracks have to be blanketed with a minimum thickness of layer of sand or earth nearly?
1) 1m
2) 1.2m
3) 1.5m
4) 2m
Q8)
The sudden release of elastic strain energy stored in the pillars results violent burst of coal pillars is called?
1) Air blast
2) Bumps
3) Rock burst
4) Main fall
Q9)
Headings advancing in a direction at right angels to the main cleat are called?
1) bords
2) end places
3) walls
4) splits
Q10)
The method suitable for working seam under the workings of another seam which is water logged or on fire is?
1) Longwall retreat
2) Bord and pillar
3) Hydraulic mining
4) Longwall advancing
ANSWERS FOR ABOVE QUESTIONS
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