Prediction of ground stability through convergence velocity

Convergence velocity, as an indicator for stability of coal mine roadways has been used in this study. The concept has been extended to a spectrum of conditions in several coal mines resorting to bord and pillar system. Several junctions in each mine were instrumented to establish the value of critical convergence velocity just prior to the onset of ground instability. Depending on the convergence velocity, the status of ground stability has been categorised as “Safe”, “Unsafe” and “Liable to immediate collapse” zones.