The phenomena may be defined as sudden highly violent failure or the collapse of the rock under high stresses causing damage to site of occurrence and the earth tremors extending in some cases up to the surface.
Rock burst is associated with hard rock mining at great depth of very high intensity. Main cause of rock burst is excessively high inherent or induced stresses or when shock waves intercept through critically stressed strata. Rock burst mainly exhibited in shaft, development heading, mineral pillars and slopes.
Causes of Rock bursts:
- Depth of mining and related with primary pressure of the rock mass.
- Thickness of deposit being mined.
- Lithological character of rock mass.
- Tectonic and discontinuity planes.
- Geo-mechanical characteristics of rock mass.
- Stress induced by extraction of the mine.
- Occurrence over the deposit top rocks by of light strength and great thickness.
Factors affecting proneness to Rock bursts:
- Mining method.
- Concentration of mining operation.
- Spatial limits of mining.
- Undercutting of mine.
- Defective mine working.
- Defective preventive technique.
Controlling measures for Rock burst:
- Maintaining sequence and direction of mining.
- Proper design of mining systems.
- Adopting best monitoring and control measures.
- Support of working.
- Clean mining.
- Discontinuation of mining.
- Analyzing hazards levels.
- Informed and strategic blasting.
- Sustained stability in the underground excavations.
