Which ventilation method is primarily used to dilute hazardous gases?

Exhaust ventilation is primarily used to dilute hazardous gases because it effectively removes contaminated air from a specific area or workspace and replaces it with fresh air from outside. This method helps to create a controlled airflow that directs harmful gases away from workers, thereby reducing the concentration of these gases in the vicinity. The principle behind this approach is to maintain air quality and ensure that any hazardous airborne contaminants are vented outside the work area, which is critical for the safety and health of personnel in mining environments.

In contrast, other methods such as recirculation systems can potentially reintroduce contaminants back into the workspace since they rely on circulating air within the mine rather than expelling it. Natural ventilation might not provide consistent control over air quality, as it can depend on external weather conditions and does not guarantee sufficient dilution of hazardous gases. Supply ventilation introduces fresh air but may not effectively remove harmful gases if there is no adequate exhaust system to draw them out. Therefore, exhaust ventilation is the most effective method for diluting hazardous gases in mining operations.