Finding a misfire in your heading is part of your workplace inspection.
Once you wash down your heading and scale from good ground to bad ground look for misfires. If the misfire is under supported ground then take care of the misfire A.S.A.P.
If the misfire is out under unsupported ground then you have to
1. Support the open ground to the misfire
2. Then take care of it either by washing it out or use a non sparking spoon to try and clean out the hole.
If the misfire can not be washed out or properly cleaned out then you have to get however many caps, powder and fuses to set it off before advancing the heading.
"Remember no matter the job, large or small, do it right or DON'T DO IT AT ALL!!!"
- A.J. Balderrama, Hard Rock Miner