- Author
-
Chekan, G. J.
|
Listak, J. M.
- Title
- Design Practices for Multiple-Seam Longwall Mines.
- Coporate
- Bureau of Mines, Pittsburgh, PA
- Report
-
RI 9360
1993
39 p.
- Keywords
-
coal mines
- Identifiers
- mining; ground control
- Abstract
- The U.S. Bureau of Mines is investigating longwall panel and gate road layouts to increase coal recovery and reduce multiple-seam interactive problems. This report presents design practices for longwall mining multiple seams to provide mine planners and operators with practical guidelines for designing productive longwall mines. Key aspects of mine design that control longwall interactions are examined, including sequencing of seams, design of gate road pillars, and orientation of gate roads and longwall panels. Theories that describe stress transfer between multipel seams and the mechanics of interaction are addressed in relation to geology. Common longwall designs were further investigated using a boundary element model, MULSIM/NL. The model provided insight into relative stress transferand distribution that occurs between longwall operations in multiple seams. Findings from the model show that (1) a longwall panel should be mined from the gob to the solid coal of an overlying mine, because the stress concentrations are lower; the approach angle should be kept under 30 deg; and (2) when mining in descending order, superpositioning gate roads usually produces the worst stress condition. To prevent this, the overlying isolated gate roads should be positioned from the centerline toward the headgate side of the underlying panel.