The only problem in the detonation was that the fuse burned out at a splice so that it did not happen at the expected time. The fuze was fixed and the explosion, when it occurred, was- if anything- even more damaging than expected. In summary, technically the mine was successful, it was the follow-up assault that went wrong.
Incidentally, in the video, Mr. Green alludes to the innovative ventilation system. In fact, using fires and canvas barriers for mine ventilation was an established practice.
I apologize but I need to postpone our video discussion until next Monday. I just got called to a Mummers Parade meeting tomorrow night. ‘‘Tis the season!!!