Practical Considerations in Longwall Support Behaviour andGround Response

摘要

This paper examines the interplay between longwall supportrndesign/geometry features, operational controls and geological features onrnground response. Experience from several investigations is used torndemonstrate the influence of factors such as longwall support capacityrnand geometry, setting pressure, coal seam strength and stiffness,rntip-to-face distance and hydraulic supply and control system parametersrnon longwall ground response. These factors are then used to outline thernrequirements on key controls such as retreat rate and cutting height andrntheir influence on allowable roof convergence.rnThe ground response curve concept as a means to provide graphicalrnrepresentation of longwall support and strata interaction processes isrnpresented. The approach was developed to address the requirement for arnpractical longwall support evaluation and selection tool that can takernaccount of support load influences such as changes in roof geology orrncover depth. An example of the comparison between single pass longwallrnand top coal caving in a thick seam environment is given to demonstraternthe influence of the various factors discussed.