How should an auxiliary fan be positioned for optimal performance?

Positioning an auxiliary fan to prevent recirculation of air is crucial for optimal performance in underground mining environments. When air is recirculated, it can lead to a buildup of contaminants and reduce the effectiveness of ventilation. By strategically placing the fan to avoid recirculation, fresh air can circulate effectively and displace stale air, ensuring a safer and healthier working environment for miners.

For auxiliary fans to function properly, achieving a balance of airflow throughout the mine is essential. Proper placement helps in maintaining a consistent supply of fresh air, especially in areas where working conditions may compromise air quality. Thus, focusing on the prevention of air recirculation significantly contributes to enhancing the overall ventilation system in the mine.

The other options, while they may have certain merits individually, do not address the critical issue of air quality and contamination as effectively as preventing recirculation does. For instance, placing the fan close to the air source may not necessarily ensure efficient air distribution, while positioning it near the mining face could lead to variations in air quality depending on work activity in that area. Similarly, a central location may distribute air evenly but may not effectively prevent recirculation in all parts of the mine.