A coal mine bump (a bump, a mine bump, a mountain bump, or a rock burst) is a seismic jolt occurring within an underground mine due to the explosive collapse of one or more support pillars,. In room and pillar mining, tunnels are advanced in a rectangular pattern resembling city streets (tunnels), leaving behind blocks (pillars) of coal. To a miner, a partially completed tunnel resembles a room dug into the coal seam. As mining proceeds, the weight of rock overburden previously supported by coal mined from rooms is redistributed to pillars. If that weight exceeds the strength of a pillar, the pillar can fail by crushing or exploding. An explosive failure is called a “bump.”