Q271
For what depth of coal seam from surface, the distance between centers of adjacent pillars shall not be less than 45 m for a gallery width of maximum 4.8 m?
A.
60 - 90 m
B.
90 - 150 m
C.
150 - 240 m
D.
240 - 340 m
AnswerAnswer: Option D
Solution
Answer: Option D
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