Proceedings: Mechanics and Mitigation of Violent Failure in Coal and Hard-Rock Mines. Washington, DC: U.S. Bureau of Mines, 1995 May; :141-165
Longwall mining in the Western United States has long had to contend with the regular occurrence of pillar and panel coal bumps, primarily resulting from deep cover [generally 450+ m (1,500+ ft)], massive sandstone units in the main roof, strong immediate roof and floor strata bounding the coal seam, and the high stress concentrations created along panel peripheries, particularly in multiple-seam workings. To assist mine operators in recognizing bump-prone geologic conditions and, ultimately, in avoiding those entry configurations that further contribute to bump-inducing stress concentrations, this paper summarizes the experience of Western U.S. longwall operations over the past decade. More specifically, this paper highlights those mining conditions that most greatly contribute to bump occurrences, several mining practices that tend to aggravate bump-prone settings, and the problems associated with "critical pillars," the primary contributors to gate road bumps. While U.S. Bureau of Mines research continues to develop proven gate road design technologies, this report serves as a summary of bump control through mine design for Western longwall mines.