Coal Mining - Study Mode
[#116] For employing the French method of extraction of thick seams, seam gredient should not exceed.
Correct Answer
(B) 35°
[#117] Main fall occurs when the area of extraction is nearly equal or more than of the depth.
Correct Answer
(C) Square
[#118] Sliding bolts are provided in
Correct Answer
(C) Scaffold
[#119] Wooden planks made of
Correct Answer
(B) Sol
[#120] In shallow mines, to prevent breathing of air to the depillared area through cracks on surface, the cracks are blanketted with a layer of sand nearly . . . . . . . . meters thick.
Correct Answer
(D) 1.2 m