Coal Mining - Study Mode
[#171] Minimum factor of safety in design of pillar in bord and pillar mining.
Correct Answer
(D) 2
[#172] Speed of rotation in saw toothed drilling
Correct Answer
(D) 5 - 10 rpm
[#173] While working contiguous seams ventilation may be through
Correct Answer
(C) Staple pit
[#174] Ventilator used in sinking shaft commonly with a capacity of
Correct Answer
(C) 300 m 3 /min
[#175] The method of drilling not belongs to Rotory drilling
Correct Answer
(A) Churn drilling