A coal burst is a sudden, destructive, and violent collapse of the coal walls in underground mines. The collapse involves a loud noise, violent explosion, and ground vibration resulting in the deaths and injuries of miners. Fragments of coal are ejected from the walls at high speed.
Coal bursts are dangerous because they can occur without any warning.
Harlan County in Kentucky is known to be the most burst-prone area in the Eastern U.S according to the International Journal of Mining Science and Technology.
Coal bursts in Harlan County have been reported since 1934 although the incidents are quite infrequent. Since 1983, eight mines out of 250 mines in the area have reported coal bursts.
Most of the bursts have occurred due to a mining system called pillar recovery. Pillar recovery is a mining system that is used in underground coal mining in the U.S. Pillar recovery has more risks for miners than other underground mining methods.
In pillar recovery, large blocks of coals in the form of pillars are left in place to support the weight of the overburden. The coal in the pillars is subsequently recovered but there is always the risk of roof falls.
Mining practices are constantly being modified and refined to prevent coal bursts. This might involve determining novel mining extraction methods and figuring out specialized requirements for mine layouts.
In the meantime, coal bursts in Harlan County remain a risk as long as there is an untapped reserve of coal and underground mining continues.