Mining Publication: Coal Mine Bumps: Five Case Studies in the Eastern United States
This Bureau of Mines study was conducted to obtain a better understanding of the coal mine bump problem and its effect on underground coal mining in the eastern United States. To accomplish this, information was collected on the geologic conditions, mining techniques, and engineering parameters at five bump-prone mines. Two geologic conditions have been found to cause the occurrence of bumps in the eastern United States: (1) relatively thick overburden and (2) extremely rigid strata occurring immediately above and below the mine coalbed. Additionally, the probability of bump occurrence is increased by certain mining practices that concentrate stresses during retreat mining in areas where geologic conditions are conducive to bumps. Mining plans that permit the development of pillar line points or long roof spans that project over gob areas should be avoided because these features may contribute to the occurrence of bumps.