Drilling And Blasting - Study Mode
[#436] The sources of leakage of air in a mine are
Correct Answer
Crushed coal pillars
[#437] The quantity survey can be made in gassy mines of I degree once in every . . . . . . . . days.
Correct Answer
(C) 14
[#438] We understand millisecond as
Correct Answer
(B) $${frac{1}{{{{10}^3}}}^{{ ext{th}}}}$$xa0part of second
[#439] The void formed after extraction of solid block of are called.
Correct Answer
(B) Stope
[#440] Moderately deep coal mines lie between.
Correct Answer
(B) 200 - 450 m