On hearing the French attack, Micca and a comrade barred a door at the top of the steps leading down to the lower level of the mines. As the French grenadiers attempted to break down the door, Micca sent away his comrade, lit a very short fuse and placed it in two barrels of gunpowder behind the door. The gunpowder exploded as the French grenadiers broke down the door, killing and injuring most of them. Micca was severely injured in the explosion and died due to his injuries and poisonous carbon dioxide gas, which had been released by the exploding gunpowder.