Which one of the following statements is not correct with regard to heading and henching method of tunnelling?
A
Driving of tunnel is done in two portions of its section
B
Driving the top portion is done in advance of the bottom portion
C
The holes in head and bench are loaded together with explosive for blasting
D
Firing of head holes is done just before the bench holes are fired
Correct Answer: Firing of head holes is done just before the bench holes are fired