What should be done with a misfired borehole's contents after waiting a prescribed time?

• A. Refill with explosives
• B. Wash the hole
• C. Cover with soil and leave
• D. Ignore and walk away

Answer: (B)

The key idea here is safety after a misfire. If a borehole doesn’t detonate as planned, there can still be unspent explosive material and debris in the hole. Waiting the prescribed time helps ensure any delayed initiation is unlikely, but you must remove the hazardous contents before proceeding. Washing the hole uses water to flush out and carry away the explosive residues and debris, reducing the risk of re-ignition or a secondary detonation when work resumes. This approach is far safer than putting more explosives back in, covering the hole and leaving it, or simply walking away, all of which leave dangerous material in place and create a clear danger to people and subsequent operations.