The maximum safe working load shall not be more than what fractions of the breaking load for 915 meters or less and over 915 meters?

The maximum safe working load shall not be more than what fractions of the breaking load for 915 meters or less and over 915 meters?

• A. 1/5 for 915 meters or less and 1/4 for over 915 meters
• B. 1/4 for 915 meters or less and 1/5 for over 915 meters
• C. 1/3 for all lengths
• D. 1/6 for all lengths

Answer: (A)

In hoisting systems, the maximum safe working load is always a fraction of the rope’s breaking load, to provide a margin against shock, wear, and dynamic effects. For mine hoist ropes, this fraction depends on the rope length. If the rope length is 915 meters or shorter, the safe working load must not exceed one-fifth of the breaking load. If the rope length exceeds 915 meters, the safe working load may be up to one-fourth of the breaking load. This two-tier rule accounts for how length-related factors influence how much load can be carried safely.

In hoisting systems, the maximum safe working load is always a fraction of the rope’s breaking load, to provide a margin against shock, wear, and dynamic effects. For mine hoist ropes, this fraction depends on the rope length. If the rope length is 915 meters or shorter, the safe working load must not exceed one-fifth of the breaking load. If the rope length exceeds 915 meters, the safe working load may be up to one-fourth of the breaking load. This two-tier rule accounts for how length-related factors influence how much load can be carried safely.