Coal dust is exploded in a Pittsburgh mine shaft to judge the effect of the explosion.
Titles read: "Flaming Death! America, too, has its mining disasters - and here's an experimental explosion made during research work on the dreaded coal dust."
Pittsburgh, Pennsylvania, United States of America.
Various shots of coal dust being exploded in a mine shaft in an experiment to judge the effect of the explosion. Men run out of the shaft before the blast.