Study reveals alarming rock displacements in Indian longwall mines
The researchers monitored the behavior of the roof in a shallow Indian longwall mine with hard sandstone cover using mine-induced microseismicity and borehole televiewer data. They found that the roof was divided into three zones: Caved Zone, Fractured Zone, and Continuous Deformation Zone. The height of the Destressed Zone was around eighteen times the mining height. Events in the Fractured Zone had the lowest b-value and highest occurrence frequency. Massive fractures and water seepage were observed in the Fractured Zone at a depth of 40-50m. Events in the Fractured Zone had the highest magnitude and energy. Abnormal changes were seen in microseismic event properties when encountering hard rock and faults. The study helped enhance safety in longwall mines by understanding dynamic roof displacement and failures.