Question

The value of Bending factor of rope used in winding as per CMR-2017 is

• A. 100
• B. 120
• C. 80
• D. 150

Hint:

This is another key number to memorize from the mining regulations.
The D/d ratio is a fundamental concept in wire rope engineering.
A larger ratio means less bending stress and a longer fatigue life for the rope.
100 is the standard minimum for many hoisting applications.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question asks for the minimum value of the "Bending Factor" for a winding rope as specified in the Coal Mines Regulations, 2017.

Step 2: Detailed Explanation:
The Bending Factor is the ratio of the diameter of the winding drum or sheave (D) to the diameter of the wire rope (d).
\[ \text{Bending Factor} = \frac{D}{d} \] This ratio is critical for the service life of a wire rope.
If the rope is bent around too small a drum, the bending stresses will be very high, leading to rapid fatigue and premature failure.
To prevent this, regulations specify a minimum value for this ratio.
According to Regulation 84(2) of the Coal Mines Regulations, 2017:
"The diameter of the winding drum or sheave shall not be less than

100 times the diameter of the winding rope, or of such size as may be approved in writing by the Chief Inspector."
Therefore, the minimum value for the bending factor (D/d ratio) is 100.

Step 3: Final Answer:
The value of the Bending factor of rope used in winding as per CMR-2017 is 100.
This corresponds to option (A).