Rock burst

Rock burst is a sudden, violent fracture of rock that can occur in high-stress environments, typically within underground mines. This phenomenon is characterized by the rapid release of energy stored in rock, leading to explosive spalling, ejection of rock fragments, and in severe cases, significant damage to mine workings and potential harm to miners. Rock bursts are a major safety concern in the mining industry, particularly in deep-level mining operations where the overlying rock exerts high pressure on the rock being mined.

Causes and Mechanisms

The primary cause of rock bursts is the high stress concentration in the rock surrounding mine openings. This stress can be due to the weight of the overlying rock, geological faults, or the removal of support due to mining activities. When the stress exceeds the strength of the rock, it can fail suddenly and violently. Factors contributing to rock burst risk include the depth of the mine, the type of rock, mining methods, and the geometry of mine workings.

Prevention and Mitigation

Efforts to prevent or mitigate rock bursts focus on managing the stress in the rock and improving the strength and flexibility of the rock mass. Techniques include:

• Destress Blasting: Controlled blasting to relieve stress in high-risk areas.
• Support Systems: Installation of rock bolts, steel sets, and shotcrete to reinforce rock around mine openings.
• Layout Design: Planning mine layouts to minimize stress concentrations and to distribute stress more evenly.
• Monitoring: Use of seismological monitoring equipment to detect microseismic events that may precede a rock burst.

Impact

Rock bursts can have severe consequences for mining operations, including damage to infrastructure, interruption of production, and injury or death to miners. The economic impact can also be significant, due to the cost of repairs, increased safety measures, and lost production.

Historical Incidents

Several notable rock burst incidents have occurred throughout mining history, underscoring the importance of effective management and mitigation strategies. These incidents often lead to advancements in understanding and preventing rock bursts.

See Also

• Mining
• Seismology
• Geotechnical engineering