Question

Considering `I' as `intake' and `R' as `return', the ventilation symbol for the shaft-bottom air-lock in a coal mine is

• A.
• B.
• C.
• D.

Hint:

Shaft-bottom air-locks are essential in coal mines to control airflow and ensure that intake and return air do not mix, maintaining a safe ventilation system.

Answer 1

The Correct Option is A

In a coal mine, the shaft-bottom air-lock is designed to separate intake air (I) from return air (R) to maintain proper ventilation and prevent short-circuiting of air. The correct ventilation symbol for a shaft-bottom air-lock typically shows the intake air entering vertically (I) and the return air exiting vertically downward (R) after passing through the air-lock, represented by two adjacent circles (indicating the air-lock doors). Option 1 correctly depicts this configuration, with I entering from the top and R exiting downward, maintaining the separation of airflows. The other options either show incorrect airflow directions or do not represent a typical air-lock setup.
Thus, the correct answer is Option 1.