When can auxiliary fans and tubing be utilized?

Auxiliary fans and tubing play a crucial role in ventilating underground mines. They are typically used in conjunction with line brattice systems to enhance airflow and ensure proper ventilation throughout the mine. Utilizing auxiliary fans can help to direct air to areas where it is most needed, particularly in sections that may not be adequately ventilated by the main ventilation system alone.

By employing auxiliary fans alongside line brattice, mine operators can improve air quality, reduce the risk of hazardous gases, and maintain a safer working environment for miners. This helps in maintaining optimum airflow rates, ensuring that fresh air reaches working faces effectively. This option leverages the strengths of both systems, rather than treating them as mutually exclusive.

Other reasons for the incorrectness of the other options include the restrictive nature of the first choice, which limits the use of auxiliary fans to emergencies only, diminishing their usefulness in regular operational scenarios. The third choice focuses on a failure scenario, which doesn't encompass the broader, proactive use of auxiliary systems during normal conditions. The final option incorrectly implies a conflict between auxiliary fans and line brattice, whereas they are designed to work together optimally for underground ventilation.