Question

The angle of draw in a trough subsidence helps in

• A. Maximum subsidence
• B. Extent of surface subsidence
• C. Plane of failure
• D. Critical width of opening

Hint:

The angle of draw is mainly used to estimate \[ \boxed{\text{the lateral extent of the surface subsidence zone}.} \]

Answer 1

The Correct Option is B

Step 1: Recall the definition of angle of draw. The angle of draw is the angle formed between the vertical through the edge of an underground excavation and the boundary of the surface subsidence zone.

Step 2: State its significance. It is used to determine how far the effects of underground mining extend on the ground surface. Hence, it helps in determining the \[ \boxed{\text{Extent of surface subsidence}.} \] Therefore, \[ \boxed{(B)} \] is the correct answer.