31914 Mitsubishi Hojyo coalmine accident (Japan, 687 casualties)
At the Mitsubishi Hojyo coalmine, a gas explosion resulted in the deaths of 687 people. This explosion was so impressively powerful that the mines elevator cage was blown up about 15 meters into the air. Some say that the explosion affected anyone within a 200-meter distance of the mine entrance as well. This also happens to be the deadliest mine accident ever for Japan.