Mitsui Miike 1963
At 3.12 p.m. on 9 November 1963, a thunderous explosion took place. At the bottom of the first mining level, ten of the four-wheeled carts filled with coal were being hauled to the surface. One of the lower three carts derailed and, because of the tension thereby created, the chain of the third cart broke. At 1,180 metres from the entrance, eight cars began a free-fall run to the bottom of the mine. They ran free for about 360 metres, increasing their speed by 33 metres per second, the momentum breaking archway support frames in the mine. Then all of the carts were derailed and turned over. At this point the explosion took place.
The rapid air displacement caused by the high-speed carts created air currents which caused the settled coal dust to mix with the surrounding air. It is possible that the friction caused by the carts turning over produced the spark that ignited the coal dust; alternatively, the crashing carts could have damaged the high-voltage cables, and this could have been the ignition point for the explosion. The compression caused by the explosion moved toward the mine entrance, and, 100 metres from the first explosion, a powerful second explosion was created. It has been estimated that the wind created by this second explosion was probably travelling at a rate of 1,000 metres per second. The compression from the second explosion, as it headed toward the bottom of the mine, fortunately did not touch off another explosion, but the carbon monoxide that was created by the two explosions spread throughout the entire mine, creating a disastrous poisoning situation.
At that time the second shift of workers (2 to 10 p.m.) had just started entering the mine, and some of the first-shift workers (6 a.m. to 2 p.m.) were in the process of leaving. Twenty people were killed by the direct effects of the explosions, but 438 died from acute carbon monoxide poisoning, and 839 suffered the after-effects of poisoning. 1,197 of the 1,403 workers in the mine at the time were either killed by the explosions or suffered from carbon monoxide poisoning. There is to date no other coal-mine accident in the world that has produced such a large number of casualties.
This accident claimed the lives of 438 people.