What term refers to the arrangement where intake air crosses return air current in underground workings?

The term that specifically refers to the arrangement where intake air crosses the return air current in underground workings is "air crossing." This phenomenon occurs when two air currents flow in opposite directions; one is the fresh intake air entering the mine to provide ventilation, while the other is the return air, which has been used and is being expelled from the mine. Understanding air crossing is essential for mine ventilation design, as it affects the efficiency of air flow and the potential mixing of fresh and contaminated air. Proper management of air crossing is vital for maintaining air quality and ensuring the safety of miners.

In contrast, "air exchange" generally pertains to the broader concept of replacing stale air in a space with fresh air, which doesn't necessarily describe the specific interaction of air currents. "Air lock" refers to a sealing mechanism to prevent airflow, often used in areas requiring controlled environments, and "ventilation shaft" is a vertical structure used to provide fresh air to underground workings but does not describe the interaction of currents. Thus, "air crossing" is the most precise term for the described arrangement.