What is necessary to prevent short circuiting of ventilating current in a mine?

Hanging doors in pairs to form air locks is an effective method to prevent short circuiting of ventilating current in a mine. This technique allows for better management of airflow, helping to direct and control the movement of ventilating air through the mine. When doors are arranged in pairs, they create a barrier that reduces the likelihood of air bypassing, which can occur if single doors are used. Pairs of doors maintain the pressure differential needed for efficient ventilation, ensuring that fresh air reaches the work areas and harmful gases or dust are adequately expelled.

In contrast, using single doors may not provide sufficient resistance to prevent air from flowing too quickly from one side to the other, which can disrupt the airflow patterns necessary for maintaining good ventilation. Installing exhaust fans, while beneficial for air movement, does not directly relate to the prevention of short circuiting in terms of the physical barriers needed. Operating doors with hand cranks does not address the airflow management aspect and can lead to inconsistent door functioning, ultimately compromising the ventilation integrity.