JNTU B.Tech IV MINE GROUND CONTROL Previous Question Paper (December - 2020 - R15)

The two prominent ground control practices currently adopted in Indian coal mines to enhance safety and productivity are the implementation of Roof Bolting with Cable Bolting and the use of Real-time Strata Monitoring Systems.

1. Roof Bolting and Cable Bolting: Modern Indian underground mines have shifted from traditional timber supports to systematic roof bolting. This practice involves installing high-tensile steel bolts into the roof strata to create a reinforced beam, effectively pinning weak immediate roof layers to a stronger, competent horizon. In deeper mines or areas with complex geological conditions, cable bolting is used as a secondary support system. These long, flexible tendons are anchored deep into the strata, providing high load-bearing capacity to prevent large-scale roof falls and control bed separation.

2. Real-time Strata Monitoring Systems: To move from reactive to proactive ground control, mines are increasingly deploying electronic monitoring instrumentation. This includes the use of multi-point borehole extensometers (MPBX), load cells, and convergence meters connected to data loggers. These sensors provide continuous, real-time data on roof movement, pillar stress, and strata deformation. By analyzing this data, mine engineers can identify trends indicative of impending instability, such as abnormal convergence rates, allowing for the timely implementation of remedial measures like additional bolting or the evacuation of personnel before a failure occurs.

These practices are supported by the DGMS (Directorate General of Mines Safety) guidelines, which emphasize the transition toward mechanized support systems to minimize human exposure to unsupported roof areas and to manage the geomechanical challenges associated with deeper coal seams.