Q173
What is the purpose of a "collar" in shaft sinking?
A.
Explosive loading zone
B.
Opening for drilling
C.
Initial reinforced shaft opening
AnswerD.
Shaft ventilation device
Answer: Option C
Solution
Answer: Option C
Solution:
Collar is the reinforced surface opening of a shaft.The correct answer is: Initial reinforced shaft openingIt stabilizes the ground near the surface and provides a solid base.Critical for long-term shaft safety.