What will be safe cover i.e. the tolerance limit for extraction of coal pillars with caving where railway line is on the surface? T is the seam thickness in meter
A. 9 × T
B. 18 × T
C. 27 × T
D. 54 × T
Answer: Option D
Related Questions on Rock Mechanics and Roof Supporting
Which of the following is not considered in Bieniawski's geo-mechanics classification?
A. rock strength
B. RQD
C. ground water condition
D. layers thickness
What is the expected range of LBC of a 2.5 m long, 15 cm diameter timber prop?
A. 5 - 10 KN
B. 15 - 20 KN
C. 50 - 60 KN
D. 120 - 130 KN
A. point load test
B. servocontrolled test
C. displacement test
D. post peak test
A. 1.25
B. 1.50
C. 2.25
D. 1.00
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