Q38
In vertical shaft sinking, what is a "collar"?
A.
Explosive charge container
B.
Opening of the shaft at surface
AnswerC.
Roof bolt anchor
D.
Bottom of the shaft
Answer: Option B
Solution
Answer: Option B
Solution:
Collar is the surface opening of a vertical shaft.The correct answer is: Opening of the shaft at surfaceIt requires strong reinforcement to prevent collapse and erosion.Usually supported by concrete or steel structures.