All fuses must extend to what length beyond the collar of a blasting hole?

• A. 3 feet
• B. 1 foot
• C. 6 inches
• D. 5 feet

Answer: (A)

A safety distance rule governs how far a fuse should extend beyond the collar. Three feet is the minimum length prescribed so you have enough fuse to burn down to the charge while you’re still at a safe distance from the blast. This extra length provides a reliable buffer in case lighting or handling is imperfect, helps ensure you can retreat to a safe position before the detonation, and reduces the chance of heat, sparks, or fuse friction affecting you or the initiating system. Shorter lengths don’t give that safety margin, and longer lengths aren’t required and can create unnecessary hazards or clutter.