What is inrush?

• A. A planned water injection
• B. Unplanned or uncontrolled flood of liquid, gas or other material that has the potential to create a hazard
• C. A normal air flow surge
• D. A scheduled gas release

Answer: (B)

Inrush is an unplanned or uncontrolled flood of liquid, gas or other material entering a part of the mine, with the potential to create a hazard. This captures the essence of the term: it happens unexpectedly, isn’t controlled, and introduces substances that can endanger workers, equipment, or ventilation conditions. For example, a sudden water inflow from a breached aquifer or a rapid gas influx can disrupt airflow, increase drowning risk, or raise explosion hazards if flammable gases are involved.

The other options describe planned or normal situations, not unplanned floods: a planned water injection is deliberate and controlled; a normal air flow surge is a routine ventilation fluctuation; a scheduled gas release is a planned operation.