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Results 211 - 214 of 214
1/1/1992 - Information CircularsA U.S. Bureau of Mines investigation of longwall panel layouts to maximize coal recovery and minimize interactive problems in multiple-seam operations.
1/1/1990 - Conference papersThis U.S. Bureau of Mines paper discusses the importance of an interface slip mechanism between the coalbed and the surrounding strata in controlling the extent and pattern of stresses and deformations in a coal pillar.
1/1/1987 - Information CircularsInformation was collected at 5 bump-prone mines. Among the findings, two geologic conditions have been found to cause bumps in the eastern U.S.: relatively thick overburden and extremely rigid strata immediately above and below the mine coalbed.
1/1/1976 - Reports of InvestigationsExamination of several coalbeds in Walker County, Alabama, Cambria, Greene, and Fayette Counties, Pennsylvania, and Caleigh and Wyoming Counties, West Virginia, indicates that cleat orientations are similar throughout a vertical sequence of strata. Stud...