Science: Explosion Weather

Since 1936, the U.S. has had 41 major coal mine explosions. Coal mines are almost weatherproof, but Meteorologist Charles L. Hosier of Penn State nevertheless suspected that the explosions had some connection with the weather. Last week he had what looked like proof.

Hosier investigated all 41 explosions to find out what the weather had been outside the mines at the time. In all cases except one, there had been sharp drops in barometric pressure (due to an approaching cold front or a low-pressure area). Two-thirds of the mine explosions, he found, took place a day or so after the pressure minimum.

Hosier's explanation: lowered atmospheric pressure encourages the flow of gas out of the coal. If the increase is too much for the fans to handle, in poorly ventilated mines, the gas may accumulate until it forms an explosive mixture. He thinks that mine operators should take careful note of the weather and warn their miners to be especially careful when the pressure begins to fall.