What happens to air currents if overcasts are not constructed properly?

When overcasts are not constructed properly in an underground mine, the correct outcome is that air currents can be obstructed and lose flow. Overcasts are designed to keep ventilation air on a designated path, ensuring that fresh air reaches the working areas and that contaminated air is removed effectively. If these structures have issues, such as gaps, poor support, or incorrect alignment, they can create areas of stagnation or turbulence in the airflow.

Obstructions can lead to reduced air velocity, creating dead zones where air does not circulate effectively. This loss of airflow can result in inadequate ventilation, which may affect the health and safety of workers by allowing harmful gases or dust to accumulate. Properly constructed overcasts are crucial for maintaining an efficient airflow, supporting a safe working environment underground.