Multiple seam interactions are a major ground control hazard in many U.S. underground coal mines. The two most common types are: Undermining, where stress concentrations caused by previous full extraction in an overlying seam is the primary concern, and Overmining, ...

Various surface controls are used in mines to control the roof skin. One control that has proven to be very effective is roof screening. Roof screen effectively controls roof skin and provides a high roof surface coverage. Although many mines are reluctant ...

This report presents results of a U.S. Bureau of Mines study of longwall gob material. The objective of this work was to determine material stiffness properties of the gob for use in numerical models of rock mass response to longwall mining. Photographs of ...