The Industrial Revolution begin in Britain in the 18th Century was based on the availability of Coal to power steam engines. Later it spread to other continentals such as Europe, North America, and Japan. During the Victorian Era, International trade expanded exponentially when coal-fed steam engines were built for the railways and steamships.

Soon after the introduction of electric power into coal mines, it was discovered that lethal explosions could be initiated by electrical equipment such as lighting, signals, or motors.

HISTORY OF INVENTION Ex-Proof (Bell Signal)

Before telephone systems, a uniform system of elaborate bell signals was used for communication between the hoist men and workers in the mine.

One bell meant “hoist” – or “stop,”

Two bells meant “lower,” and

Three bells meant a man was to be hoisted, so go slow.

From there, the signals for water, emergencies and other communications became more complex.

The methane accumulation with the danger of suspended coal dust. At least two British mine explosions were attributed to an electric bell signal system. In this system, two bare wires were run along the length of a drift, The induction of the signal bell coils, combined with the breaking of contacts by exposed metal surfaces, resulted in sparks which could ignite methane, causing an explosion.