Longwall Face Stability: An Evaluation of Face Sloughage

摘要

The U.S. Bureau of Mines report examines the causes and consequences of longwallface sloughage. Theoretical relationships were developed to evaluate mechanisms that produce sloughage. From these relationships, contributory factors were identified for further analysis in field efforts. A survey identified 12 mine sites with sloughage problems, and these were investigated. From these studies, it was determined that the depth of cover and mining height are the two most significant factors causing sloughage on longwall faces. Coalbed friability and cleat orientation also were found to be significant factors in promoting sloughage. It was concluded that sloughage is primarily a problem in thicker seams or seams with friable coalbeds, and that the problem is more severe as the depth of cover increases.